STUFFING BOX

Abstract

A holder for receiving a moving rod and formed with a gland to surround the rod and housing a stack of metal rings, at least some having and inside diameter smaller than that of the rod.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from U.S. application Ser. No. 61/447,023, filed Feb. 26, 2011 incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a stuffing box for sealing around a reciprocating or rotating rod.

2. Description of the Prior Art

A stuffing box (also known as a packing box, packing gland, gland, or gland seal) is a device used to prevent fluids from leaking around a rod-like member, such as a piston, rod, propeller shaft, or other usually cylindrical, moving part that passes through a hole in a pump, well-head, or other device. The stuffing box typically consists of a box, chamber, or other housing containing compressed packing materials. It seals against the rod member to retain fluid pressure below the stuffing box, and prevent leakage of fluid to the environment.

Stuffing boxes are widely used to seal with rotating and/or reciprocating rods in wells, e.g., oil wells, and in valve sterns or various types of valves, and to seal with rods or pistons of pumps and other equipment which generate or handle pressurized fluid.

Sealing materials used in stuffing boxes have historically been made from compressible soft or elastomeric materials such as greased flax, rope, cotton, ramie, graphite fiber, rubber, plastic and fluorocarbon. In many cases, axially stacked packing rings or packing glands seal between the body of the stuffing box and the rod member. The packing rings are axially compressed or loaded by adjusting a gland member moveable relative to the 20 stuffing box body, thereby exerting a compressive force on the packing rings to result in enhanced sealing. If the stuffing box leaks, the gland member is tightened to increase the loading on the packing rings, thereby resealing the packing rings with the rod member.

In the case of an oil well, for example, a fluid is artificially lifted from a down-hole pump by means of a pump jack. The upper portion of a sucker rod is typically attached to a smoothly machined rod called a polish, or polished, rod, which operates through a stuffing box. Components of the stuffing box attempt to seal against the rod member, with the object of preventing well fluids from leaking through the wellhead orifice while the rod is moving in a reciprocal or rotating fashion relative to the stuffing box.

In many applications, including the oil industry, solid particles such as sand, dirt, debris, and other forms of contaminations (hereafter “entrained solids”) are frequently present in well fluids, and are drawn in and transported, i.e., entrained, by the rod member and by the flow of fluid up into the stuffing box. Entrained solids are highly abrasive to the rod member and to components inside the stuffing box, especially if those components are made of soft, compressible, or elastomeric materials. A significant amount of fluid. escapes from oilfield stuffing boxes with worn-out packing rings, thereby creating environmental concerns. Worn components require excessive maintenance and frequent replacement, and therefore cause the pump to be inoperable for extended periods of time. Stuffing boxes for oilfield operations are associated with additional problematic conditions. Reciprocating rods can become misaligned over a period of time with respect to the axis of the stuffing box. Oilfield pumps may also “run dry” during pumped-off conditions, or may produce fluids with high water content, and during these times the components inside the stuffing box, which are normally lubricated by the down-hole fluid, are not lubricated. Thus, stuffing box components have a relatively low lifespan.

In one aspect of the stuffing box of the present invention a holder is received over a rod and includes one of more elongated glands for receiving a stack of metal rings constructed to be maintained in sealing engagement with the rod to cooperate in sealing against leakage along the surface of the rod and form a labyrinth path for fluid along the radially outside of the rings to resist leakage.

Thus, as the rod is in its upward stroke, it is first exposed to those wiper/seal components with the widest internal diameter annuli, which allows liquid to pass through but prevents passage of the largest entrained solids. As the rod is exposed to tighter and tighter wiper/seal components, the size of entrained solid that can pass through is smaller and smaller, until finally the internal diameter annuli of the wiper/seal components is so tight that not even the fluid itself can pass through the annulus. This results in a tight seal around the rod member, preventing even well fluid from passing through the annulus. Thus, the rod is exposed first to wiping, then to wiping combined with sealing, and then to a final sealing, so that the successive stages and tapering of the wiper/seal components of the stuffing box prevent leakage of well fluid from the stuffing box.

Rings: By the use of wiper/seal rings, a stuffing box as presently set forth can wipe and seal a rod member in stages using a series of rings. The rings employed have the ability, in varying degrees, both to seal against the rod to prevent leakage of fluid which would otherwise leak around the surface of the rod as it exits the stuffing box (“sealing”) and to remove entrained solids from the well fluid as it enters and progresses through the stuffing box (“wiping”). The degree to which any given ring is effective at wiping or at sealing depends on its internal diameter annulus.

Due to the mode of assembly, the internal diameter annulus of each ring depends in turn on its location in the stuffing box. Those rings closest to the well-head, where the rod is pulling fluid up into the stuffing box, act primarily as wiping rings. The wiping rings wipe off debris, preventing debris suspended in the fluid from moving up the shaft alongside the rod, and thereby prevent such solids from rubbing against, and causing abrasion to, the rod. Rings closer to the top of the stuffing box function chiefly as sealing rings, and prevent fluid from leaking out of the stuffing box. A ring which is located intermediate between the top and bottom of the stuffing box performs both wiping and sealing functions. The closer a particular ring is to the top of the stuffing box, the more its function shifts from that of predominantly wiping to predominantly sealing.

If there is a stack of rings, each with a very small gap, it is unlikely that anything can get through those rings. The area of the gap is very small, and there is not enough pressure to push the fluid through the gap.

Wiper/seal rings can be stainless steel, precision double wound retainer rings, such as, for example, stainless spiral retainer steel rings constructed of 0.0625 inch thick windings. Wiper/seal rings are made from stainless steel or brass sealing components which may be slightly softer than the rod member. Sealing and wiping is therefore possible without causing damage to the rod member, which is made from a harder material. The stuffing box can therefore operate for months to years without any adjustments.

In one aspect the improved stuffing box can incorporate one or more collets to wipe, to seal, and to hold the rod in vertical alignment within the stuffing box (“align”). As with the wiper/seal rings, the degree to which a collet is configured to either wipe or seal is a function of its location within the stuffing box. Improvements over prior stuffing boxes can be obtained by, in some embodiments, using collets which include compression grooves. The compression grooves are lengthwise slots through the side walls of the collet. Where the slots stop short of the ends, extending only partially the length of the collet, i.e., so that the compression groove does not go all the way through, leakage of well fluid past the seal is further minimized.

During assembly a compressive force can be exerted downward on the one or more collets from a component above, such as a top cap or adjusting nut. In some embodiments it is preferred that a fixed nexus be maintained between the top cap/adjusting nut and the one or more collets. Preferably, the component is secured by a fixed linkage to the top cap to avoid pressure problems on collets below. A fixed linkage can be obtained by use of a circumferential groove around the upward end of the collet, by which the collet is secured to the top cap. In some instances, the collet is secured to the top cap by a swivel linkage.

It is advantageous that when in operation the rod be kept in proper alignment within the central axial shaft of the stuffing box. The one or more collets contribute best to keeping the rod in proper alignment, thereby stabilizing the rod, when the length of a single collet for where multiple collets are present, the total combined vertical length of the collets) is at least one to two times the diameter of the rod, preferably 15 to 3 times the length of the diameter of the rod, or even four times the length of the rod.

Collets can perform the alignment of the rod member, and perform preliminary wiping and sealing.

Collets can be adjusted so that they have a larger internal diameter annulus than sealing rings or scraper cones higher or lower in the stuffing box. In this way, the collets remove debris and some oil, allowing water to pass through in order to cool the subsequent seals and other stuffing box components. The edges can be beveled, flat, knife-like, or rounded with a radius.

In some embodiments, it is feasible to retain the advantage of length of alignment conferred by multiple collets by using a single but more elongated collet.

Scraper cones and sealing rings can serve as additional sealing stages and can be designed with progressively smaller internal diameter annuli to become progressively tighter around the rod member, or, to have progressively shorter axial length in order to scrape with stronger pressure against the rod member.

Holders, also referred to as carriers or cassettes, are used to keep collets, wiper/seal rings, and scraping cones in place inside the stuffing box. The holders are manufactured as cassettes that can slip fit into the stuffing box when the stuffing box is being assembled. During assembly, the internal components can be dropped into place using a cassette-type mode of assembly. This allows for easy replacement of collets, wiper/seal rings, and scraping cones, and further facilitates easy repairs or replacement of the rod member.

In some embodiments, the holder can be a beveled holder. The beveled holder is around rings to introduce taper in seals within one set of wiper/seal rings. In other embodiments, the holder, e.g., a beveled holder, is used to compress a collet. The holders adjust the tightness of the collets and wiper/seal rings to specified internal diameter annuli around the rod member.

Use of a tapered ring holder to collapse the internal diameter of a set of wiper/seal rings results in a truncated pyramid type design, as shown in FIG. 4. Thus, in operation, as the rod member comes upwardly through the wiper/seal rings, there is some play. As the rod continues to move upward, the rod is wiping and sealing. By the time the rod is at the sealing chamber, the rod is clean of contamination, and there is no contamination to interfere with sealing.

It is notable that there is a decrease in wear and tear of the internal parts of the stuffing box by removing debris at the point of entry, both at the top and at the bottom points of entry of the stuffing box.

Use of a straight-walled ring holder results in a set of wiper/seal rings having internal diameter annuli which are all aligned with the outer surface of the rod member.

Tight sealing is optimized by the use of metal components, so that there are metal to metal contacts between moving parts. This creates good metal cling, so that the gap between the sealing components and the rod member is so small that there is no leakage. Using metal components, and avoiding fibrous parts inside the stuffing box, also minimizes wear and tear and lengthens the lifespan of the component parts.

In another aspect of the invention, either a round wire or a swivel nut can be used to connect the stuffing box to the well head adapter. This gives the stuffing box freedom to wobble or swivel slightly in accordance with any swivel in the well head.

In another aspect of the invention, the upwards outer surface of the top cap can form a catch basin. The catch basin is formed by the top cap having a dished top, which doubles as a tube basin for pump ups or work overs. By “dished top” is meant an angle in or conformation of the top cap that forms a dish, basin, collecting device, or holding pool for fluid. The catch basin collects well fluid, such as oil and water, and then acts as a lubrication basin (“lube basin”). The advantage of having a lube basin in the top cap is that there is no lost time, and no heat and friction, caused by the pump up, i.e., work over, process. In other words, were the pump to stop, oil in the casing or along the shaft of the stuffing box would ordinarily leak to the bottom of the well. The pump then has to pump up oil before the pump can start up again. This causes heat and friction to the pump and stuffing box, because during the pump up process the surfaces of the moving parts are dry. By having a catch basin in the top cap of the stuffing box, fluid is in the cap, and can flow back down into the stuffing box and pump shaft during the pump up process, so that the pump up procedure will not create heat or friction.

Additional mechanisms for achieving control over the temperature of the stuffing box system are achieved by the present staged and tapered approaches to wiping and sealing. For example, the bottom seals, such as bottom wiper/seal rings 901 and 902, and scraping cones 333, wipe but do not completely seal, which removes entrained solids from the well fluid, in turn preventing wear and tear on components inside the stuffing box. Temperature control is accomplished by allowing the relatively clean well fluid to travel a good way up the stuffing box, thereby lubricating the rod member, and keeping the temperature down inside the stuffing box.

Applications of the staged stuffing box include reciprocal and rotating pumps as used in oil, gas, and water wells, oil transfer pipeline pumps, and other applications with abrasive, oily fluids, or environmentally hazardous fluids. Other applications include use of the stuffing box to seal rotating or reciprocating rods against high pressures of 50 psi to 3000 psi or more.

The above embodiments can be used with reciprocating rods, or adapted for use with rotating rods by addition of bearings, for example near the entrance and the exit of the stuffing box, or the bushing can perform for this role. Ports to admit lubrication or allow gases to exist can be included through the top cap, well head adapter, or housing. A free floating polished rod lubricator, not shown, with felt wiper pads can be installed on the rod member just above the stuffing box to supply additional lubrication to the rod member and stuffing box components. When no oil is being produced, this lubrication prevents the polished rod from heating up and damaging the stuffing box components. A rod rotator can also be used to rotate and scrape paraffin or scale off of the rod member.

For certain applications such as at oil well heads and the like, rotating of reciprocating rods may run 24 hours a day, 7 days per week all year long subjecting the stuffing box to considerable wear and frequent leakage thus requiring expensive repair, maintenance and replacement. The problem is exacerbated by leakage of petroleum fluids and contaminated water through defective seals often leaving the environment contaminated by petroleum waste and the like creating problems for the operators and oftentimes charges that there have been violations of the environmental laws. Given there are some 750,000 oil well heads just in the US, as well as some 85,000 in Canada, another 90,000 in Mexico and 70,000 in South America, one can see why there has been significant need for a leak proof stuffing box.

In recognition of the need there have been many efforts to propose stuffing box designs to solve the leaking and wear problems. Many proposals have been made incorporating packing rings of various fibers, material and shapes, including V-shaped in cross section packing rings shown in U.S. Pat. No. 2,567,479 to Hebard, Chevron shaped rings shown in U.S. Publication No. 2006/0272804 to Tessier and stacked fiber rings shown in U.S. Publication No. 2009/0211750 to Toporowski.

Other efforts have proposed a stand pipe around the pumping or sucker rod such as shown in U.S. Publication No. 2005/0011642 to Hult or back pressure as disclosed in U.S. Publication No. 2009/0166046 to Evardson.

Various types of specially shaped elastomeric seals packing rings and fiber sealing rings have been tried, such as those shown in U.S. Pat. No. 3,967,678 to Blackwell.

To applicant's knowledge, none of these devices have been accepted in the field as providing for positive sealing against leakage over extended periods of time. There thus exists a need for a stuffing box with robust and reliable sealing characteristics and which will operate for extended periods of time without repair and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention are shown in the accompanying drawings which, together with the description thereof, will serve to exemplify the invention. The particular structures illustrated can be modified by those skilled in the art without departing from the broad scope of the invention.

FIG. 1 is an axial cross section of a stuffing box;

FIG. 2 is a top view (2A) and a side view (2B) of collet 23, 601, or 701, showing an even number of compression grooves 28 (FIG. 2A), and collet groove 45 (FIG. 2B);

FIG. 3 is an axial cross section of another stuffing box;

FIG. 4 is an illustration of use of a tapered ring holder 302 to compress the internal diameter annuli of intermediate and bottom wiper/seal rings;

FIG. 5 is an illustration of use of a straight tapered ring holder 302 to compress the internal diameter annuli of intermediate and bottom wiper/seal rings;

FIG. 6 is a schematic illustration of the use of C rings between the top cap and collet of a stuffing box;

FIG. 7 is an axial cross section of a stuffing box in which the broadest faces of the intermediate collets are facing each other;

FIG. 8 is an axial cross section of yet another stuffing box, including a port and a pressure gauge;

FIG. 9 is an axial cross section of a stuffing box using adjustable scraping cones 20 to wipe;

FIGS. 10A and 10B are top and side view of a scraping cone, respectively;

FIG. 11 is an axial cross section of a stuffing box using “C” rings and scraper cones to affect a seal;

FIG. 12 is an axial cross section of another stuffing box which uses multiple scraping cones for wiping;

FIG. 13 is a vertical sectional view of an embodiment of the stuffing box of the present invention for use with a rotary rod; and

FIG. 14 is a vertical sectional view of a another embodiment of the stuffing box of the present invention for use with a reciprocating rod.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Applicant has designed a stuffing box employing an arrangement of multiple annular components that wipe and seal in stages. Those annular parts having the largest internal diameter are proximal to the bottom, well head side of the stuffing box, where “internal diameter annulus”, as used herein, refers to the distance between the internal diameter of the annular component and the outer diameter of the rod member. The intermediate and upper wipers and seals have progressively narrower internal diameter annuli.

Optionally, the upper most seals can open up again to a wider internal diameter annulus. For example, the internal diameter annulus of the intermediate or upper sealing rings can be four fifths to nine tenths smaller than that of bottom wiper/seal rings. Wiper/seal rings appropriate for the invention are laminar rings, or, e.g., the WSm series rings from Smalley Steel Ring Company, e.g., WSm #162. These are double rings. The internal diameter annulus forms a dynamic seal designed to allow the facing sealing parts to seal and slide against rod member 14. The direction of the decrease in the internal diameter sealing annuli of individual wiping and sealing parts can narrow downwards, upwards, or narrow then get wider again, in relation to the bottom well head. side of the stuffing box.

Instead of using separate parts to effect a narrowing of internal sealing annuli, individual parts, such as a bushing, sealing ring, or collet can be provided with a conically beveled interior.

As a rod member reciprocates up and down through the seals, trapped debris that tends to abrade seals has a more favorable path to migrate in a direction towards the larger, looser internal diameter sealing annuli, rather than get stuck in and abrade the smaller tighter internal diameter sealing annuli.

The preliminary seals perform partial wiping and sealing, and. reduce pressure drop against well fluid, in order to better enable and protect subsequent, tighter or secondary sealing stages. The protection of seals through staged sealing protects both preliminary and secondary seals and allows use of more robust seals made from hard materials that take longer to wear and therefore last longer without significant leaking. Combinations of different types of seals together around a rod member, where rod member 14 is held in alignment by a bore, bushing, or collet are preferred. The collets and bushings can perform both wiping or sealing and alignment.

For the purpose of this application I intend the term “cling” to mean for the purpose of wiping rings that the rings are constructed of material having an inside diameter equal to or less than the diameter of the rod and having sufficiently resiliency to block flow debris in fluid and high viscosity fluids as that associated with petroleum products and for sealing rings to block flow of water.

The term resistance from labyrinth and circuitous flow shall mean sufficiently small annulus and sufficiently tortious path sufficient restrict to flow of petroleum fluid and water to such a small stream to allow only for cooling and lubrication.

Combinations of seals can be achieved by combining two or more bushings, collets, scraping cones, or sealing rings. Both the inner diameter against rod member 14 and the outer diameter against the housing of stuffing box components need to be sealed. The outer diameter sealing annulus is defined as the space between the outer seal, scraping cone or collet diameter and the inner diameter of the housing. The outer diameter sealing annulus can also be designed to slide, or to move up and down, to help seat the seal or other component. Seals and other components can be fixed or attached to the housing.

The outer diameter of seals, collets, bushings, scraper cones, or other parts can also be constructed to fit in the gland of the housing so as to have effectively no outer diameter sealing annulus. Sealing rings can have one or both of an inner or outer diameter sealing annulus that varies from 0.005 inches down to 0.0005 inches. Collets and bushings can be designed to have a relatively wider sealing inner or outer annulus, for example from, preferably 0.04 inches to 0.02 inches.

It is also preferable to combine parts with sealing edges that have different axial lengths, so as to present different sealing interfacial area contact stress. For example, parts such as bushings and collets have relatively wide axial length sealing edges, for example, over one eighth (⅛) inch, and a relatively loose fitting scaling annulus. These parts perform preliminary or primary wiping, sealing, and pressure drop of well fluids. Bushings and collets arc structurally strong and can provide simultaneous function to align rod member 14.

Scraper cones and sealing rings have relatively narrow sealing edges, for example, under one eighth (⅛) inch.

The collets, scraping cones, and sealing rings can have grooves, preferably partially cut through, to allow adjustably tightening against rod member 14 by compression caused by turning the top cap against the internal parts. These grooves are generally axial and can be angled.

Internal parts can include bushings, collets, collet and ring holders, ring holders, and spacer blocks.

Bushings, collets, collet and ring holders, ring holders, and spacer blocks can be designed to fit together at angles of less than 90 degrees so that the collets or scraping cones can slide away from the housing and towards the rod when compressed, thereby uniformly collapsing the compression grooves, tightening the internal diameter of these parts, and providing structural support.

Parts with surface faces that slide-ably seal or form sealing faces against rod member 14 include collets, scraping cones, and sealing rings. These can be made from a metallic, hard, or wear-resistant material, alone or combined or with a coating, surface treatment, or protective. layer. The robust hard materials used as seals and sealing faces preferably include materials which are less hard than the outer material of rod member 14 to prevent wear and scoring of rod member 14, as indicated by the Rockwell hardness score (“RWC”). By way of example, where the rod member has a RWC hardness of around 45-46, all the sealing parts have a RWC of around 39-40, so the sealing is softer then the rod and will seal without causing damage. Examples of materials that can be used as seals and sealing faces include, without limitation, bronze, brass, stainless steel, babbitt metal, polycrystalline diamond, hexagonal boron nitride, ceramics, engineered polymers, filled polymers, materials chosen for wear resistance in water or a particular fluid, such as ultrahigh molecular weight polyethylene and thermoplastic polyester, and materials with a good combination of wear resistance and tribological properties. The seals can be of uniform material, or, the back, non-sliding, housing face of the seals can be attached to compressible, plastic, or rubber materials. Seals and sealing facing faces can also be made using an intermetallic alloy such as, e.g., Cr₃Si/Cr₁₃Ni5Si2, which. consists of Cr₃Si primary dendrites and interdendritic Cr₃Si/Cr₁₃Ni5Si2, which has a good high-temperature sliding wear resistance. See, Zhang et al., Materials Letters, 57(18): 2710-2715, May 2003

A compressible seal, gasket, or O-ring can be placed behind ring holders 3, or behind ring and collet holders 10, in order to prevent leakage of well fluids behind these parts.

In another embodiment, wiper/seal rings can be split. The split wiper/seal rings can act like a spring, and spring inwards if the sealing annulus is increased due to wear, in order to re-tighten the sealing annulus against rod member 14.

FIG. 1 illustrates an axial cross-section of stuffing box 100. Stuffing box 100 includes housing 9, having housing top end 91 and housing bottom end 92. Housing 9 as shown in FIG. 1 has a straight, cylindrical axial internal bore. In alternative embodiments (see, e.g., FIG. 4), housing 9 can have built in annular or axial grooves or shoulders against which sealing components can be seated.

The rod member 14 has a constant diameter and is arranged to move in reciprocal fashion through the central axis of housing 9 in stuffing box 100, and in and out of the well through the well head below (not shown). Further attached to and within housing 9 are components such as bushing, collets, holders for securing the collets and holders for securing the wiper/seal rings. The bushing, collets, holders, and wiper/seal ring components have internal diameters that define an annular bore around rod member 14, so that rod member 14 can slide up and down while being scraped, wiped and sealed.

Housing 9 is attached to well head adapter 12 with round wire 24. Well head adapter 12 threads into the well head (not shown) via well head adapter threads 19. Round wire 24 allows stuffing box 100 to swivel in relation to well head adapter 12

The internal diameter of well head adapter 12 defines a bore into which fits alignment bushing 17 optionally, alignment bushing 17 can be flanged; see bushing flange 27, which is a flange portion of alignment bushing 17. Alignment bushing 17 receives, aligns, and preliminarily wipes rod member 14. In some embodiments, the internal diameter of alignment bushing 17 can be tapered towards the top (not shown) to better receive rod member 14, and align rod member 14 within the axis of housing 9 without causing side wear.

Top cap 1 is an adjusting nut. Top cap 1 is secured to housing 9 by top cap threads 11, and further secured against vibration by top locking nut 6, using top locking nut spanner wrench hole 41. Top locking nut 6 can likewise contain an optional bushing (not shown). Top cap 1 can be provided with optional spanner wrench holes 5.

Top wiper/seal rings 401 are secured in a groove of top cap 1. The internal diameter annuli of top wiper/seal rings 401 are aligned against the outer surface of rod member 14, forming a sufficiently tight seal against rod member 14 to seal off well.

Collet 23 is attached to top cap 1 at point 42. Point 42 is a location at which collet 23 is connected to, or attached to, top cap 1. The connection between collet 23 and top cap 1 at point 42 is, e.g., a joint, or can be a fixed attachment between the two parts, or can be a swivel connection. Where a swivel attachment is preferred between collet 23 and top cap 1, point 42 can include, e.g., a swivel nut, an embedded round wire, axial pins, or a mechanism known to those skilled in the art to allow the attached collet 23 to rotate or swivel in relation to the top cap 1.

Without limiting other advantages and features of the invention, one advantage of a connection, attachment, or joint at point 42 between top cap 1 and collet 23 is that, collet 23 can be easily removed from housing 9 by lifting off or otherwise removing top cap 1, which contributes to ease of maintenance and replacement of parts.

Screwing down top cap 1 against threads 11 tightens collet 23 against rod member 14. Top cap 1 exerts pressure downward on collet 23, causing collet 23 to tighten against rod member 14, to wipe fluids, if any, from rod member 14, and to align rod member 14, as explained more fully below.

Collet 23 is a cone shaped, annular part with an outer and an internal diameter, made from a relatively thick piece of metal, or other hard material, with a thickness greater than one eighth (⅛) inch thick.

Holder 101 is a metal part prepared from, e.g., alloyed steel or stainless steel, or brass, which during assembly is slip fit into housing 9. Alternatively, housing 9 and holder 101 can be machined so that holder 101 is an integral portion of housing 9. Holder 101 stabilizes the position of collet 23. The shape of holder 101 is angled to fit together with opposing angles in collet 23, so that downward axial compression from top cap 1 is translated and distributed into a compressive force in the axial direction against rod member 14. Holder 101 can function merely to compress and hold the collets; alternatively, holder 101 can also act as a carrier, e.g., a holder or cassette, for intermediate wiper/seal rings 801 (as shown in FIG. 1).

As shown in FIG. 1, holder 101 can include a ring housing to define a groove to hold intermediate wiper/seal rings 801, which are secured in the groove of holder 101 below collet 23. Intermediate wiper/seal rings 801 have a smaller internal diameter annulus than bottom wiper/seal rings 901 or bottom viper/seal rings 902.

The internal diameter annuli of the wiper/seal rings within the set of intermediate wiper/seal rings 801 taper going upward in the direction of housing top end 91, thereby gradually forming a tighter and tighter seal against rod member 41

In the embodiment as shown in FIG. 1, top wiper/seal rings 401 are built into a notch in top cap 1, and have a sufficiently small internal diameter annulus to form a leak proof seal. Intermediate wiper/seal rings 801 thereby provide a secondary stage of wiping and sealing against rod member 14.

The embodiment in FIG. 1 shows bottom wiper/seal rings 901 and 902 positioned in a notch in the lower portion of housing 9. Bottom wiper/seal rings 901 can be of the same internal diameter as bottom wiper/seal rings 902, or of a smaller internal diameter than bottom wiper/seal rings 902. In the context of an oil well, for example, bottom wiper/seal rings 901 scrape and wipe rod member 14 to remove debris and sand, and remove some to most of the oil, but allow some water to leak upwards into the stuffing box 100 and cool the parts and components in the upper portions of the stuffing box 100

Bottom wiper/seal rings 901 have a larger internal diameter than intermediate wiper/seal rings 801, which cling and seal more tightly to rod member 14. Top wiper/seal rings 401 can be smaller in diameter than the intermediate wiper/seal rings 801, and therefore tighter around rod member 14 than the other rings and collet 23, in order to provide a final seal. Thus, successive stages of wiper/seal rings (e.g., bottom to intermediate to top) perform successively tighter wiping and sealing stages.

FIG. 2 shows both a top view and a side view of collet 23/601/701. At least four, five, and preferably six, seven, or eight or more compression grooves 28 are cut into the walls of collet 23/601/701. Preferably, there is an even number of compression grooves 28. One option is for compression grooves 28 to be evenly spaced. apart around the walls of the collet 23/601/701. As shown by use of alternating solid and dotted lines to depict the compression grooves 28 in FIG. 2A, each compression groove 28 cuts only partially the length of the axial dimension of collet 23/601/701, which minimizes leakage of fluid through the collet.

As shown in FIG. 2B, in some embodiments, collet 23 can include collet groove 45, which can mate with top cap collet attachment shoulder 44 to form a swivel connection between collet 23 and top cap 1 (see FIG. 3).

Suitable collets for use in a stuffing box of the invention are, without limitation, TG-style collets (Teehnikuse.com).

An alternative option is for holders to be beveled, so that the faces of the holders match both the larger facing area of the preceding collet, and the smaller facing are of the succeeding collet.

An elongated collet 23 attaches to top cap 1 by a swivel connection, in which collet groove 45 is held in position by top cap collet attachment shoulder 44. Intermediate wiper/seal rings 801 are secured to holder 302 by snap ring 442. Bottom wiper/seal rings 901 are secured in ring holder 303 by snap ring 443. Snap rings appropriate for the invention are W8 or V8 series snap rings from Smalley Steel Ring Company.

In operation, as rod member 14 pulls oil to the surface on its upward stroke, it first moves past a series of six bottom wiper/seal rings 901, positioned in holder 302 and held in place with snap ring 443, Wiper/seal rings 901 allow for about a 0.005 to 0.007 clearance between the internal diameter of the wiper/seal ring 901 and the rod member 14. This amount of clearance is suitable for wiping off most debris, while allowing fluid through to the next set of wiper/seal rings, intermediate wiper/seal rings 801.

in the example shown in FIG. 3, intermediate wiper/seal rings 801 are a set of 49 rings, each 0.0625 inches thick, placed in a tapered ring holder 302. The intermediate wiper/seal rings 801 have internal diameters suitable for providing clearances, the bottom-most ring starting at an internal diameter of 0.005 inches over the diameter of rod member 14, and tapering to tighter diameters of 0.001 to 0.002 inches over the diameter of rod member 14. Any fluid allowed in past the intermediate wiper/seal rings 801 now acts as a cooler and lubricant for this set of wiper/sealing rings 801.

Above the intermediate wiper/seal rings 801 is a collet 23. Although collet 23 can add a degree of sealing, the primary function of collet 23 is to hold rod member 14 in straight alignment as it passes through the wiper/seal rings.

Collet 23 is adjusted with the use of collet holder 101, which is held in place with snap ring 441. Collet 23 is attached to an adjusting nut, top cap 1. Collet 23 has a groove, collet groove 45, which is free to swivel in top nut collet attachment shoulder, which is a pocket of top cap 1. This design allows for the adjustment of the collet 23 and will not allow the collet 23 to be either sucked down, which would increase tension, or to be lifted up, which would relieve tension. Instead, the collet tension is kept constant.

Above collet 23, but still held in top cap 1, is a set of C-rings 39, held in place with C-ring compression blocks 50 and seating force adjusting nut and bolt 49, as adjusted via Allen wrench socket 48.

As rod member 14 moves up through the stuffing box, it is cleansed of most debris by bottom wiper/seal rings 901. Rod member 14 continues upward through intermediate wiper/seal rings 801, the lower of which act predominantly as wipers, and the progressively upper-most rings of which act predominantly for sealing. Rod member 14 then continues further upward through an alignment collet 23, which keeps rod member 14 aligned. Due to the alignment provided by collet 23, rod member 14 keeps it's alignment through the main body of the stuffing box as it passes through the wiper/sealing, rings. As rod member 14 exits collet 23, it passes through C-rings 39, which act as an additional set of wipers.

FIG. 4 is an illustration of use of a tapered ring holder 302 to compress the internal diameter annuli of intermediate wiper/seal rings 801.

FIG. 5 is an illustration of use of a straight tapered ring holder 302 to compress the internal diameter annuli of top wiper/seal rings 401.

FIG. 6 is an axial cross section of the top portion of an embodiment which employs “C” rings to form a seal. The “C” rings have an inner diameter facing “C” shape which creates a spring 47. When compressed, the C-ring bulges outward and can therefore be adjustably compressed to form a leak tight seal against rod member 14. An advantage of the “C” ring is that the spring resulting from the “C” shape automatically adjusts the seal face outwards to tighten against rod member 14 in response to wear or in response to any shrinkage which may result from changes in temperature. The top cap 1 compresses C-rings 39 between optional washers 40 and stuffing box components located beneath, such as collet 601. Washer 40 can also separate “C” rings 39 or other components. The C-rings 39 can be attached to holders 501, 502 etc. (secured by 0-rings 201, 202, and 203), can be an integral material, or can employ a metal “C” around an elastomeric or polymer 0-ring. For added or more uniform compressibility, the “C” ring 39 can also employ multiple perforations along the middle or perimeter of the seal as described in U.S. Pat. No. 6,357,760 B1, herein incorporated by reference.

FIG. 7 is an axial cross-section of a stuffing box, where the embodiment shown in FIG. 7 includes top collet 701, bottom collet 704, intermediate collet 702, and inverted intermediate collet 703. The broad face of bottom collet 704 is directed to the bottom of the stuffing box. The broad face of the top collet, collet 701, is directed toward the top of the stuffing box. The direction of alternate intermediate collets is inverted, to form pairs of opposing pairs of collets, as shown by intermediate collet 702 and intermediate collet 703. Thus, the broad face of intermediate collet 702 faces the broad face of inverted intermediate collet 703. The broad faces of the opposing pair of collets 702 and 703 are directly touching each other and of equal area. Optionally, more than one pair of two opposing intermediate collets 702/703 can be used (not shown).

Further in FIG. 7, holders 102 secure the position of the collets 701, 702, 703, and 704, and further secure the position of intermediate rings 801, 802, 803, and 804. The holders are secured by O-rings 202.

FIG. 8 is an axial cross section of an additional embodiment where the housing 9 contains a port 38 through a pipe 36 that connects by a hole through the housing 34 to a reservoir 33. A pressure gage 35 can be used to actuate a valve 37 or other control means, to move a fluid by pressure into reservoir 33. The pressurized fluid prevents well fluids from leaking which would contaminate or abrade top wiper/seal rings 401 in order to safeguard these top wiper/seal rings 401, which effect a final seal of fluids from leaking outside the stuffing box.

Alternatively, port 38 can be used to relieve pressure in reservoir 33, optionally through valve 37, which is actuated by pressure gage 35, or by a temperature sensor in the packing box (not shown). The valve 37 can he a pressure valve or a check valve.

Port 38 can also he used as a fluid bypass for well fluid that leaks up through the seals, bushings, collets, or scraping cones. This bypass can connect to a low pressure side of the pump, such as the outlet of the “T” or other well fluid collection or holding means.

Alignment bushing 17 can be used to align rod member 14, shown in this case with optional top and bottom bushing flanges 27 to support the other packing box components. An advantage of this embodiment is that the bypass relieves pressure on the top wiper/seal rings 4 or sealing components, to extend the length of time with which these provide a leak proof seal. Another advantage of this embodiment is that fluids in reservoir 33 help maintain lubrication and cool seals, wipers, collets, bushings, and other stuffing box components, thereby extending component and seal life. In order to provide cooling fluid to the stuffing box reservoir, the port 38 can also be used as an inlet for water, oil, grease or other cooling fluid.

FIG. 9 is an axial cross section of a stuffing box in which adjustable scraping cones 331, 332 are placed above collet 23 in housing 9. Scraping cone holder 211 holds and stabilizes the scraping cones 331, 332, and provides a groove for positioning intermediate wiper/seal rings 801. Compression of top cap 1 against the internal parts such as the scraping cone holder 211 or additional ring holders 402 tightens the scraping cone holders 211 against rod member 14 and 0-ring 221, which also forms a seal against housing 9.

Further in FIG. 9, top wiper/seal rings 401 are secured in a groove of top cap 1; top wiper/seal rings 402 are secured in a groove of ring holder 301, which is attached to housing 9 by 201.

Collet 23 is elongated, such that collet 23 has a length longer than its width. Collet 23 seals, scrapes and wipes well fluids from rod member 14. Additional sealing and wiping is performed by scraping cones 331, 332.

Scraping cone holder 26 can be used to transmit compression from top cap 1. Top cap 1 is screwed down upon housing 9 in order to compress the scraping cones 331, 332 and collet 23 against rod member 14. Top wiper/seal rings 401 and O-rings 221 seal, so that well fluids are prevented from flowing along the inner diameter of the housing 9.

Bottom wiper/seal rings 901 and 902 scrape and wipe well fluids such as sand, oil, and water from rod member 14. The bottom wiper/seal rings 901 and 902 can be larger in diameter than the intermediate wiper/seal rings 801. Top wiper/seal rings 401 can be smaller in diameter and therefore tighter around rod member 14 than the other rings and collets, in order to provide a final seal.

In lieu of or in addition to rings, scraping cones 331, 332 can optionally be employed at the bottom of the stuffing box to do more of the preliminary wiping and sealing.

FIGS. 10A and 10B are top (10A) and side views (10B) of a scraping cone 311, showing scraping cone compression grooves 29. A scraping cone is a similar cone shaped part made from a relatively thin piece of metal, for example, one eighth (⅛) inch thick or less, preferably made from brass or bronze. The diameter of the scraping cone 311 are adjustable by virtue of compressing against grooves 29, which are slits in the outer diameter of the scraping cone 331.

The scraping cones can be adjusted to seal loosely or more tightly, for use to either wipe sand and debris, or seal against fluids like oil and water, or to allow some water to pass through. A scraping cone can be employed singly, or as two or more staggered cones. The edges can be beveled, flat, knife-like, or rounded with a radius.

An example of a scraping cone suitable for use in the invention can be purchased from Seal Guard Corporation, e.g., Seal Guard® part number 3436-1500.

FIG. 11 is similar to FIG. 3, where an elongated collet 23 attaches to top cap 1 by a swivel connection, in which collet groove 45 is held in position by top cap collet attachment shoulder 44. Intermediate wiper/seal rings 801 are secured to holder 302 by snap ring 442. Bottom wiper/seal rings 901 are secured in ring holder 303 by snap ring 443.

In FIG. 11, scraping cone holder 211 can be secured in a notch of top cap 1. Scraping cone 331 is secured to scraping cone holder 211 and top cap 1 by snap ring 201.

FIG. 12 is an axial cross section of an additional embodiment using adjustable scraping cones 331, 332, 333, 334, 335, and 336 to wipe instead of the adjustable collets in the other embodiments. Scraping cone holder 211 holds and stabilizes the scraping cones.

Compression of top cap 1 against the internal parts such as the scraping cone holders or intermediate ring holders 801, 802 tightens the scraping cone holders against rod member and gasket, O ring, elastomeric cushion, or stop 221, which also forms a seal against housing 9.

An elongated collet 23 attaches to top cap 1 by a swivel connection, in which collet groove 45 is held in position by top cap collet attachment shoulder 44. Top wiper/seal rings 20 401 are secured to top cap 1 by snap rings.

Scraping cone holder 211 is secured in a notch of top cap 1. Scraping cones 331 are secured to scraping cone holder 211 and top cap 1 by snap ring 201.

Intermediate wiper/seal rings 801 are secured to holder 302 by snap ring 442.

Bottom wiper/seal rings 901 are secured in ring holder 303 by snap ring 444. In operation, as rod member 14 pulls oil to the surface on its upward stroke, it first moves past a series of six bottom wiper/seal rings 901, positioned in holder 303 and held in place with snap ring 444. Wiper/seal rings 901 allow for about a 0.005 to 0.007 clearance between the internal diameter of the wiper/seal ring 901 and the rod member 14. This amount of clearance is suitable for wiping of most debris, while allowing fluid through to the next set of wiper/seal rings, intermediate wiper/seal rings 801.

Collet 23 is adjusted with the use of collet holder 101, which is held in place with snap ring 442. Collet 23 is attached to an adjusting nut, top cap 1. Collet 23 has a groove, collet groove 45, which is free to swivel in top nut collet attachment shoulder, which is a pocket of top cap 1. This design allows for the adjustment of the collet 23 and will not allow the collet 23 to be either sucked down, which would increase tension, or to be lifted up, which would relieve tension. Instead, the collet tension is kept constant.

Above collet 23, but still held in top cap 1, is a top set of wiper/seal rings 401. In the present example, top wiper/seal rings 401 is a set of six rings.

Above top wiper/seal rings 401 is scraping cone 331, which is a wiper held in place with snap ring 201.

As rod member 14 moves up through the stuffing box, it is cleansed of most debris by bottom wiper/seal rings 901. Rod member 14 continues upward through intermediate wiper/seal rings 801, the lower of which act predominantly as wipers, and the progressively upper-most rings of which act predominantly for sealing. Rod member 14 then continues further upward through an alignment collet 23, which keeps rod member 14 aligned. Due to the alignment provided by collet 23, rod member 14 keeps it's alignment through the main body of the stuffing box as it passes through the wiper/sealing rings. As rod member 14 exits collet 23, it passes through top wiper/seal rings 401, and scraping cone 331, which act as an additional set of wipers. Scraping cone 331 wipes off any contamination the rod is exposed to while it is in the open air.

EXAMPLE

A stuffing box was made and tested with the following parts and specifications. The top cap 1 made from 1018 steel material, or equivalent, 6″ outer diameter, the top of the nut with a 30 degree taper, ¾″ web (thickness of the nut). The top nut internal diameter was threaded to match housing 9. The locking nut 6 was 4% inches wide and 1 inch thick. There were a minimum of four equally spaced spanner holes 5 in top nut and locking nut 6 were 0.530 inches diameter. The bottom wiper/seal rings 901 formed an internal diameter annulus against rod member 14 of between 008 inches and 0.005 inches, and were case hardened to (Rockwell Hardness C Scale or RC) RWC 35, with a finish of within 40 microns smoothness. The sealing ring hardness was therefore less then rod member 14 hardness, so as not to score or wear rod member 14. The rod member itself was RWC 45. The collet holder 101, and the ring holder, were 1018 steel material, case hardened to RWC 30, finished to within 40 microns smoothness, with an internal diameter of 1.510 inches. The intermediate wiper/seal rings 801 formed an internal diameter annulus of between 0.005 inches and 0.003 inches. The collets and sealing rings had an outside diameter machined to slip fit into housing 9 to create an outer diameter sealing annulus of 003 inches. The collets were made from 41L40 steel material, RWC 40, with a plus or minus 20 micron finish on both the internal and outer diameter. There were a minimum of three compression grooves 28, which when tightened closed allowed an internal diameter annulus of 0.002 inches. The intermediate wiper/seal rings 801 were made from 316 stainless steel material with radius on both the internal diameter and outer diameter, a finish to within 20 microns smooth, RWC 35, and an internal sealing annulus maximum of 0.002 inches. The housing 9 was 1018 steel material or equivalent, with a finish on the internal diameter machined to micron 20 smooth. The outer diameter has no surface finish requirements. The collet and ring holder 10 was made from 4340 RWC 50 steel material, finished to 20 micron smoothness, with an outer diameter or scaling annulus slip fit to the housing 9. All the threads 11 were to American Petroleum Institute (API) standards. The bottom wiper/seal rings 901 were 316 stainless steel, with a radius on the internal and outer diameters, with an inner and outer diameter sealing annulus of between 0.005 inches and 0.003 inches. The well head adapter 12 was of 1018 steel material, RWC 30, finished to within 30 microns smooth, with a knurled wrenching area and spanner slots. The rod member 14 met API specifications. The threads 19 used to connect housing 9 to the well head used API threading standards. The bottom lock nut corresponded to specifications on parts 5 and 6, and can include optional spanner wrench holes 18. The alignment bushing 17 used brass, bronze, 1018 steel or equivalent, machined on the outer diameter to slip fit into the well head adaptor internal bore, and on the inner diameter to slip fit over rod member 14. The bottom wiper/seal rings 901 were 316 stainless steel, with a radius on both the internal and outer diameter, RWC 35, with an internal diameter annulus of between 0.010 inches to 0.005 inches.

This stuffing box was field tested and installed on a well head using an active oil field reciprocating rod pump with 1½″ rod member. The maintenance crew was instructed to monitor the well. During continuous use for seventy two hours no leakage was detected at well pressures of 60 pounds per square inch or less. In this case, no leaking of any type was visible. In comparison, the previous stuffing box with a compressible, prior art packing seal had to be adjusted at least four times per twenty four hours.

In a separate bench test using a 15″ long, 10½″ 0D seamless tube with an ID of 9 1/2′ was used to simulate a well casing. This was capped with a 1″×15″ diameter flange sealed to the casing with the use of an O-ring,. The flange had 3″ NPT-API threads threaded in our stuffing box with a 1½″ polished rod to the API spec. The bottom was also capped. Using a hand pump the simulated casing was filled with kerosene and pumped to a 60 pound per square inch rating. The stuffing box was allowed to stand under up to 60 pounds per square inch pressure for 3 days during which time no leaks were visible. This stuffing box employed six collets, six bottom wiper/seal rings 13 and eight top wiper/seal rings 401.

The embodiment shown in FIG. 13 is similar to that shown in FIGS. 3 & 11 with particular application to a down-hole rotary pump, and includes an annular stainless steel holder 1001 configured with a central bore 1003 to fit over a rod such as a polished rod 14 to be connected to a sucker rod of a rotary oil well head. In this exemplary embodiment, I chose a polished rod with a nominal diameter of 1.250 inches, having American Petroleum Institute tolerances ranging from 1.240 to 1.253 inches and selected rod wiping rings with inside diameters about 1.240 inches or, in some instances, somewhat smaller to cling to the rod and facilitate the wiping process. The holder 1001 is configured with a plurality of elongated glands 1007, 1009 and 1011 for receiving selected numbers of wiper and sealing rings 1017 and 1019, respectively, selected in accordance with the particular application, considering the speed of rotation for rod 14, pressures encountered and the integrity of the sealing desired. One or more of such glands may be formed with downwardly and inwardly tapered side walls to provide somewhat of a conical shape as shown for the gland 1011. The diameter of the respective tapered gland(s) may be formed with the diameter at the lower end somewhat smaller than that of the respective expanded rings so that, upon pressing of the rings downwardly in the gland, the respective lower rings will be compressed radially inwardly to provide even more positive sealing.

The lower gland 1007 is of a sufficient height, i.e. 0.396 inches, to accept 3-5 wiping ring sets 1017, preferably a set of 3. I selected these ring sets for the respective glands 1007, 1009, 1011 to provide for progressively tighter wiping and sealing upwardly along the rod to thereby progressively remove oil, debris and grit in the lower stages and then provide positive sealing in the upper stages to provide the desired sealing effect. Each of the sets of rings 1017 are made up of laminations, including a pair of upper and lower housing rings sandwiching respective rod rings there between to provide laminated sets. As noted, the rod rings are formed with central apertures for close fit or interference fit over rod 14 with clearance between the respective outside diameters and wall of the gland while the sandwiching housing, or holder rings are formed with inside diameters to provide ample clearance around the rod but with outside diameters only 0.003 to 0.010 inches smaller than the diameter of the gland 1007 to, throughout the stack of rings cooperate with the rod sealing rings to provide a labyrinth for flow in a restricted cross section, exhibiting a barrier to upward flow of debris carried in fluid and any heavy or high viscosity oil. The rings are preferably in the form of multi-turn spiral, spring retainer rings sized so the rod wiping rings form and interference fit on the rod and the two housing rings on either side provide a close fit relative to the wall of the gland.

The housing wiping rings in the sets on either side of the rod rings are formed with an inside aperture which provides clearance for free rotation of the rod relative to such housing rings and the outside diameters of such housing rings are preferably configured with diameters of about 0.005 to 0.007 inches less than the diameter of the respective glands 1007 to cooperate together in providing a labyrinth for a restricted flow path upwardly along the gland to provide some heat exchange for cooling but without carrying debris, grit and viscous fluids. As with the rod wiping rings discussed above the rings are preferably constructed of 304 stainless steel but in some embodiments may be of softer materials.

In practice, such rings are short multi-turn spiral rings available as spiral retainer rings from Smalley Steel Ring Co. mentioned above at www.smalley.com under, for instance series number YSKDL for the rod wiping rings and housing rings of the sets 1017 for the particular size of rod in consideration and WST for the Spirolox® retainer rings to serve as sealing rings 1019 discussed below. As will be apparent from this disclosure, a multi-turn spiral retainer ring will serve the wiping function and those with 2 or 3 turns are preferable.

The intermediate gland 1009 is formed in its lower extremity with a diameter similar to that for the gland 1007 for receipt of about 10-12 ring sets 1017 for further wiping of any viscous fluid which may have migrated past the rings in gland 1007. For particular applications, progressively tighter fit of the respective sets of rings will be selected in accordance with the application.

By experimentation, I have discovered that by stacking 3 or 4 sets of rings of this construction of the ring set 1017 the stack is fairly free to slide on the rod 14 but by adding several more ring sets 1017 to the stack, some resistance will be afforded to shifting of the stack along the rod thus giving the workman a sense of the magnitude of the sealing provided. For this particular application, I selected 10 wiping ring sets 1017 for the lower portion of the gland 1009.

The upper portion of gland 1009 is formed with a slightly larger diameter leaving an upwardly facing annular shoulder on which the lower ring of a stack of sealing rings 1019 sits.

To form an effective dynamic seal, I selected multi-turn metal spiral retainer rings having inside diameters on the order of 0.020 to 0.030 inches under the diameter of the rod, and preferably between 0.020 and 0.025 inches under that diameter to thus provide a robust interference fit for highly effective sealing. I selected a stack of 20 sealing rings 1019 having a combined height of about 0.990 inches. Other numbers and constructions will occur to those skilled in the art from this disclosure, it only being important that the rod wiping rings sandwiched between the housing rings provide sufficient wiping effect to screen out debris and vicious liquids and that the sealing rings provide for positive seal to block the passage of fluid.

Similarly, for the rings in the gland 1011 I selected 23 sealing rings 1019 with inside diameters as described above to thus provide the interference fit and the positive sealing effect.

The holder 1001 is further formed with an annular bearing cavity 1031 for receipt of alignment bearings 1033 and is formed with a O-ring gland 1035 opening inwardly toward the gland for the bearings for receipt of an O-ring 1037 to provide sealing against leakage.

The holder is configured at its upper extremity with an annular cap 1040 which presses downwardly on a bearing nested in a bearing gland 1040. The holder includes an O-ring gland 1041 circumscribing the bearing for receipt of an O-ring 1043 to seal against the O-ring assembly.

The holder is further formed intermediately in its exterior with an outwardly opening O-ring gland 1045 for receipt of an O-ring 1047 to seal against a housing 1049 against escape of any liquid which may have seeped out of the annulus outside the housing rings carrying the rod rings.

Finally, the holder is formed in its lower extremity with an outwardly opening O-ring gland 1053 for receipt of an O-ring 1055 to seal against the interior wall of a cavity 1059 formed in a bottom cap 1061.

It will be appreciated that the holder may be constructed in cassette form to fit into a housing of a conventional stuffing box at a well head. Conveniently the rings 1017 and 1019 may be flexed and inserted into the respective glands in stacks sufficient to achieve the desired wiping and sealing effect for the particular application and size of the rod 14. An insertion tool or rod 14 with a tapered or bullnose end may be inserted upwardly though the bore 1003 to expand the rings as it passes for clinging thereto and to position the rod 14 in place as shown. The cap 1040 may be screwed down to apply pressure the stack of rings 1019 in the tapered gland 1011 to drive the lowermost rings downwardly into the lower extremity of such gland, causing the smaller diameter walls of such gland to contract the rings further radially inwardly to apply further radially inwardly acting forces to enhance the sealing effect. In some embodiments the lower glands are tapered in a similar fashion.

In operation, once the stuffing box of FIG. 13 has been mounted on a rotary rod 14 the rings will be in position to wipe and seal against the rod. The rod selected may be hardened and have a 40 micron finish. It is recognized that the rod may be connected to a sucker rod which may rotate at some 300 rpm 24 hours a day 7 days per week thus requiring robust and effective sealing to avoid the unsightly spillage of oil and/or water contaminated with oil or the like. Thus, when rod 14 is rotated it will be appreciated that oil and water-carrying oil may tend to seep up along the outside surfaces of the rod to thus enter the gland 1007 causing the body of such flow and any debris carried therein to be blocked by the rod wiping rings of the sets 1017 so that only minimal flow of low viscosity moistures is allowed to seep further up along the surface of the rod as it rotates at high speed thus migrating up past the rod wiper rings to continue migrating on up the shaft. I have discovered that any dust and debris so collected by the wiper rings tends to enhance the sealing effect.

Then as the fluid tends to flow up along the surface of the rod in the annulus between such a rod and the aperture 1003 it will encounter the wiping seal sets 1017 in the bottom portion of the intermediate gland 1009 to be further stripped of any remaining debris or viscous fluid. As the fluid then, possibly influenced by pressure or the like, tends to flow further upwardly, the sealing rings 1019 in the upper portion of the gland 1009 will serve to more positively block against further migration up along the surface of the rod leaving little risk of further flow along the rod. At the same time the bearings 1039 tend to maintain the rod in alignment relative to the stuffing box to thus minimize vibration and relative movement between the rod and stuffing housing. This will leave little, if any, residual fluid escaping upwardly.

In the meantime, it will be appreciated that circuitous flow path up the radially outside of the ring sets 1017 in the gland 1007 and lower portion of the gland 1009 will be restricted but that which does pass will provide for some limited heat exchange while also providing for lubrication for the spinning the rings. Further flow, around the radial outside of the rings 1019 will be blocked by the close fit of such rings to the glands 1009 and 1011 while the O-rings 1037 and 1043 block any possible fluid that might have seeped past.

In the unlikely event any residual fluid should escape along the rod 14 past the gland 1009, as because of a failure of the seals or the like, to reach the level of the upper gland 1011 the barrier provided by the stacked sealing ring sets 1019 acting against the rod will serve to thus provide positive redundant sealing against any escape whatsoever of the fluid.

This construction has proven to be effective over extended periods of time and under field conditions far exceeding any competitive products known to applicant.

Referring to FIG. 14, the stuffing box shown therein is particularly adapted for use with an oil well head including a fine finished and polished rod 14 attached to a sucker rod which reciprocates to operate a reciprocating pump for drawing petroleum products to the surface. This stuffing box includes an annular cassette type holder 1051 in a housing 1053 defining a vertical, central bore 1055 for receipt of the rod 14. The housing is carried from a well head adapter 1061 formed in its lower extremity with a annular wiper ring gland 1063. The holder 1051 is itself formed with an intermediate sealing ring gland 1065 and an upper sealing ring gland 1067. The holder is formed intermediate the glands 1065 and 1067 with an annular groove for receipt of a bushing 1071 configured in its upper surface with an upwardly opening O-ring gland 1073 and in its radially outer surface with an O-ring gland 1075 for receipt of respective O-rings 1077 and 1079.

Formed above the gland 1067 is a groove for receipt of a bushing 1079 to maintain alignment with the rod 14 and including a radially outwardly opening O-ring gland 1081 for receipt of an O-ring 1083 to seal against the housing.

Mounted above the bushing is a collet collar 1087 formed in its interior with an actuating conical cavity 1089 for telescopical receipt of an elongated conical collet 1091 carried on its upper extremity from a collet holder 1095. The collet is split with multiple longitudinal expansion slots for flexing of the walls thereof to selectively close or open the bottom extremity of the collet.

The upper extremity of the housing 1053 is configured with male threads and a top nut fitting 1101 is configured to clasp over the upper edge of wall of the housing 1053 and to be screwed thereunto. By screwing the fitting 1101 up and down on the housing the collet holder 1095 will drive the collet upwardly or relative to the collar 1087 to selectively drive the collet, for instance, downwardly to close on the rod and provide a tighter sealing and guiding arrangement with such rod.

Mounted to a radially inwardly projecting flange 1105 of the fitting 1101 is a pair of annular jaws 1107 and 1109 carried from clamping bolts 1111 arrayed around the periphery for opening and closing the clamps. The clamps are formed on their radial interior with respective, confronting circular grooves 1112 for receipt of an internal stainless steel C-seal 1113 available from Garlock Helicoflex, 2770 The Boulevard, Colombia, S.C. 29290 to provide for a positive and final seal against the rod 14.

For this application I selected a stack of spring, metal rings to act as wiper rings 1121 in the lower gland 1063. As above, I discovered that flat, expandable spiral rings, typically utilized as retainer rings serve the necessary wiping and sealing function along the length of the rod 14. For wiping rings I selected 304 stainless steel Spirolox® spiral multi-turn retaining rings available from Smalley Steel Ring Co. (mentioned above) under a number of different series, including WST to provide a wiping effect. For this application I utilize between 6 and 10 wiper rings 1121 and in the preferred embodiment selected 8 with an internal diameter of 0.005 inches less than the diameter of the rod diameter of about 1.250 inches to provide an interference fit for clinging to the rod. The glands 1063, 1065 and 1067 are formed with respective diameters only slightly larger than the unexpended diameter of the respective rings 1121 and 1125, such as 0.005 inches larger for only minimal flow in the small annuli formed around the collective stack of slightly expanded rings in the respective glands.

As will be appreciated by those skilled in the art from this description, metal rings of various different construction and configuration will serve the wiping and sealing purpose, it only being important that they are spring metal or similar material and have a sufficient interference fit with the rod for such wiping rings to block flow of viscous fluid and debris carried by the fluid and withstand wear from relative reciprocation of the rod. I prefer a 2 turn spiral helix but other turns such a 3 turn spiral springs will provide the necessary sealing. Preferably the open ends of respective adjacent rings are out of registration with one another and the stack is sufficient to create such a tortious path that any flow along the respective helix of the springs and from one spring to the next is minimal. As noted the diameter of the gland 1063 is selected to leave a minimal annulus between the gland wall and outside diameters of the rings to form a restricted tortious path preventing significant fluid flow up the annulus.

For the gland 1065 I selected metal, Spirolox® retainer rings 1125 which are also available from the Smalley under the WST and related series designation and selected those rings with an inside diameter of between 0.005 and 0.020 inches diameter less than the diameter of the rod 14 of about 1.250 inches. As will be apparent to those skilled in the art from this disclosure, this undersizing or interference fit can be adjusted for various sizes of rods and reciprocation. Again, the gland is sized to tightly fit, or even form an interference fit between the wall of the gland and the outside diameters of the slightly expanded rings to cooperatively block flow. I prefer about 15 to 24 springs in this stack and, in the preferred embodiment selected 20.

For the upper gland 1067 I selected the sealing seals 1125 in a stack of about 20 to 25 to provide the desired degree of sealing such that upward flow beyond such seals is highly restricted if not totally sealed.

From the foregoing it will be appreciated that the construction of FIG. 14 has particular application for use in blocking flow from a reciprocating rod, particularly for well heads, and that the overall construction will provide for progressive wiping and sealing along the path up along the length of the rod, as the rod is drawn upwardly initially causing the interior of the rings 1125 to wipe the rod to limit upward flow of debris and highly viscous oil and then in the upper stages provide multiple barriers and sealing interfaces by the rings 1125 to block seepage of oil and liquid from the stuffing box.

The collet 1091 may be adjusted for selected degrees of compression and support and sealing effect to enhance the sealing and, additionally, the C-seal 1113 may be adjusted to provide the optimum degree of compression against the rod 14 and sealing effect to thereby provide for reciprocation there past but to positively block and seal against seepage and escape of any liquid which might be drawn up to that level.

Claims

1. Stuffing box apparatus for fitting over a rod of a predetermined diameter to restrict flow of fluid from a first to a second end of the rod and comprising:

a holder configured with first and second end walls formed with respective central bores for receipt of the rod and including first and second ring glands spaced toward the first and second ends;

a plurality of metal rings formed with inside diameters equal to or smaller than the predetermined diameter, housed in stacked relationship in the respective glands for receipt of, and sealing against the rod to restrict flow of the fluid there along.

2. The apparatus of claim 1 wherein:

selected ones of the rings are formed with inside diameters sized to wipe against the surface of the rod with sufficient force allow for limited passage of the fluid while cooperating to block debris carried in the fluid from traveling toward the second end.

3. The apparatus of claim 1 wherein:

at least some of the rings are constructed of multi-turn retainer rings.

4. The apparatus of claim 1 wherein:

the rings are constructed of spring metal and configured to be expanded and contacted and to be expanded to fit onto the rod and to cling to the rod with sufficient force to seal against flow of the fluid along the rod.

5. The apparatus of claim 1 wherein

the rings include multi-turn spiral rings forming wiper rings constructed to cling to the rod to block the fluid from carrying debris along the rod and housing interposed between the wiper rings and formed with inside diameters larger than the predetermined diameters to provide clearance around the rod and, further formed with sufficiently large outside diameters to be received in close fit relationship with the wall of the gland to restrict flow of the fluid along the wall of the gland.

6. The apparatus of claim 5 that includes:

pairs of the space the housing rings interposed between the wiper rings.

7. The apparatus of claim 6 that includes:

expandable metal spring sealing rings stacked on the wiping rings and formed with relaxed inside diameters smaller than the predetermined diameter to cling to the rod.

8. The apparatus of claim 7 wherein:

the wiping and housing rings cooperate with the wall of the gland to form a labyrinth defining a restricted flow path for the fluid.

9. The apparatus of claim 7 wherein:

the sealing rings are constructed of 2 turn spiral rings.

10. The apparatus of claim 1 that includes:

a C-shaped-in-cross section spring metal ring for sealing against the rod.

11. The apparatus of claim 10 that includes:

a pair of jaws interposed between the holders and the spring metal spring and a compression device for selectively adjusting the jaws to compress the metal spring to adjust the force of the spring against the rod.

12. The apparatus of claim 1 that includes:

a collet collar carried from the holder;

a collet carried adjustably from the holder for engaging the rod to be adjusted for adjusting the force by which the collet engages the rod.

13. The apparatus of claim 1 that includes:

an adjustor on the holder for adjusting the axial compression on the stack of rings.

14. The apparatus of claim 1 wherein:

the holder is formed with a plurality of glands; and

a plurality of the metal rings in the plurality of glands.

15. Stuffing box apparatus for blocking fluid flow along a vertical rod of a predetermined diameter and comprising:

a holder configured with a first and second glands;

a plurality of adjustable wiping rings stacked in a first gland and formed with inside and outside diameters, the inside diameters equal to or less than the predetermined diameter and housing rings interposed between the wiping rings and formed with outside diameters to cooperate with the wiping rings and wall of the first gland to form a restricted flow path for the fluid to flow there along to provide for heat exchange with the rings but limiting passage of debris in the fluid;

the second gland being configured with a lower bore of a first diameter and an upper bore of a second diameter larger than the first diameter to form an upwardly facing annular shoulder at the transition;

a plurality of the wiper rings stacked in the lower portion;

a plurality of housing rings in the lower portion, interposed between the upper rings;

a plurality of metal sealing rings stacked in the upper portion on the shoulder and formed with inside diameters smaller than the predetermined diameter to cling firmly to the rod and block passage of fluid there along;

and a plurality of the sealing rings stacked in the third gland for sealing against flow along the surface of the rod.

16. The apparatus of claim 15 wherein:

one of the glands is formed with a vertically extending wall having frustoconical shape defining a lower extremity smaller than the outside diameter of the respective rings;

and a compression device on the holder for compressing the rings downwardly in the selected gland to cause the rings in the lower extremity to be compressed radially inwardly.

17. Stuffing box apparatus for limiting fluid flow along a rod of a predetermined diameter and comprising:

a holder formed with first and second glands;

a plurality of wiper rings stacked in the first gland, the rings being in the form of multi-turn, compressible, metal rings formed with interior diameters to, in the relaxed position, be equal to or less than the predetermined diameter;

a plurality of sealing rings stacked in the second gland, the sealing rings being constructed of multi-turn, spiral, spring metal rings to be expandable and contractible and formed with relaxed interior diameters less than the predetermined diameters to cling to the rod and block flow of the fluid therepast.

18. The stuffing box apparatus of claim 17 that includes:

a collet actuator carried by the holder and formed with a frustoconical cavity;

a collet holder;

a collet carried from the collet holder and constructed to be adjustable for expansion and contraction of the collet.

19. The stuffing box apparatus of claim 18 that includes:

a C-shaped in cross section spring seal carried from the holder and opening toward the rod to sealingly engage the rod.

20. The stuffing box apparatus of claim 19 that includes:

a pair of adjustable jaws on the holder and carrying the C-shaped in cross section spring seal.

21. Stuffing box for blocking fluid flow along a vertical rod of a predetermined diameter and comprising:

a holder configured with at least one gland;

a plurality of adjustable metal sealing rings stacked in the gland and formed with inside diameters smaller than the predetermined diameter to cling firmly to the rod and block passage of fluid there along.