Abstract: A threaded coupling comprising a first end, a second end, a first portion of the threaded coupling defining a first thread profile, a second portion of the threaded coupling defining a second thread profile different from the first thread profile, where at least two threads of the second thread profile proximate to the second end are reduced in height according to an extra machining angle.

Abstract: A connection includes a first expandable tubular member having a first screw threadform defined by a first plurality of crests, roots, and flanks, where each flank separates each crest from each root. The connection also includes a second expandable tubular member having a second screw threadform defined by a second plurality of crests, roots, and flanks, where each flank separates each crest from each root. The crests and roots are substantially axial to the tubular members and the flanks are substantially radial to the tubular members. The first expandable tubular member and the second expandable tubular member are configured to connect when the first threadform engages with the second threadform. Clearances are formed between the first plurality of flanks and the second plurality of flanks when the first and second expandable tubular members connect.

Abstract: Drill string components having at least two threads extending around a body. The leading end of each thread can have a configuration having increased strength and resistance to jamming and cross-threading. In particular, the leading end of each thread can comprise a planar surface normal to the body. The leading end of each thread can provide an abrupt transition to full thread depth that helps reduce or eliminate cross-threading and can be oriented at an angle relative to the axis of the drill string component. Each thread can further provide at least one of a variable thread width and a variable thread pitch configured to create an axial progressive fit. Each thread can also provide a cylindrical thread root and a thread crest that circumscribes a frusta-cone over at least a portion of the axial length of the threads configured to create a radial progressive fit.

Abstract: A connector for connecting pipes and for use with power tongs have a die length. The connector includes a body with threaded connection portions at each end of the body on an inside surface of the body. The connector includes a gripping surface defined on an outside surface of the body between the threaded connection portions. The gripping surface is at least as long as the die length. The connector includes a reinforced portion of the body proximate each of the threaded connection portions for increasing resistance to deformation of the body upon being connected with a pipe. The gripping surface and the reinforced portion together facilitate an increase in connection torque of pipes connected with the connector.

Abstract: In a threaded connection of a two-step thread construction including intermediate shoulder surfaces, a break is prevented near the intermediate critical cross sections upon application of a tensile load, and the intermediate shoulder surfaces are easier to create, thus improving productivity. The outer periphery portion of a pin located between an intermediate shoulder surface of the pin and a second male thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near the pin intermediate critical cross section PICCS. The inner periphery portion of a box located between an intermediate shoulder surface of the box and a first female thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near a box intermediate critical cross section BICCS.

Abstract: An oil well tool operable to be deployed downhole on a production string including a tubular member having a wall extending from a first end to a second end opposite the first end and the wall forming a plurality of apertures. The oil well tool also includes a mesh screen coupled to an inner surface of the wall of the tubular member and covering the plurality of apertures.

Abstract: A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

Abstract: A threaded connection for steel pipe is provided that can be made up quickly and appropriately. The threaded connection includes a steel pipe 20m, a steel pipe 20f, and a coupling 50 for connecting the steel pipes 20m and 20f. The pipe bodies 21m and 21f of the steel pipes 20m and 20f include annular marking grooves 23m and 23f, respectively, formed on the outer peripheries of the pipe bodies 21m and 21f.

Abstract: A directly connected drill pipe applicable to extreme conditions includes a tool joint pin and a tool joint box, where an external pipe section is located on an external side of a threaded section of the tool joint pin, and an annular groove is formed between the external pipe section and the threaded section of the tool joint pin. An insertion section of the tool joint box can be inserted into the annular groove in a matched manner. A main shoulder of the tool joint pin is located at an end of the external pipe section, a main auxiliary shoulder of the tool joint pin is located on a bottom surface of the annular groove, and an auxiliary shoulder of the tool joint pin is located at a small end of the tool joint pin. The tool joint box has three corresponding shoulders which form a 3-stage sealing with the tool joint pin.

Abstract: A connection tube (1) for connecting two tubes (8, 9) of different alloys, wherein the connection tube has a central through-hole extending along a longitudinal axis and comprises a first end portion (2) of a first alloy, a second end portion (3) of a second alloy, and a middle portion (4) which is at least partly double-layered with said second alloy forming an annular inner layer and said first alloy forming an annular outer layer, wherein a metallic bond has been formed between said layers. The inner and outer layers are mechanically interlocked by means of at least one helically extending thread formed in an interface between said layers. The connection tube is manufactured from a base component and an outer component threaded onto the base component to form a work piece, which is hot worked to form a metallic bond.

Abstract: A threaded coupling comprising a first end, a second end, a first portion of the threaded coupling defining a first thread profile, a second portion of the threaded coupling defining a second thread profile different from the first thread profile, where at least two threads of the second thread profile proximate to the second end are reduced in height according to an extra machining angle.

Abstract: A threaded connection includes a first tube having a pin, the pin having pin threads, a circumferential concave outer pin surface, and a pin torque shoulder at a free end, the concave outer pin surface including a pin seal surface and a continuous extension from the pin seal surface to the pin torque shoulder. A second tube has a box, the box has box threads for interacting with the pin threads, a circumferential inner box surface and a box torque shoulder. The inner box surface has a radially inwardly extending box seal surface, the pin seal surface contacts the box seal surface to define a seal. The seal is spaced from the free end when the pin and box torque shoulders contact, the continuous extension continuing from the seal to the pin torque shoulder. A method for making-up a threaded connection is also provided.

Abstract: A threaded connection includes a pin and a box. The pin includes, in the order from a free end side of the pin toward a tubular body side thereof, an inner sealing surface, an inner male threaded portion, a shoulder portion, an outer male threaded portion, and an outer sealing surface. The box includes, in the order from a tubular body side of the box toward a free end side thereof, an inner sealing surface, an inner female threaded portion, a shoulder portion, an outer female threaded portion, and an outer sealing surface. Between the inner sealing surface and the inner female threaded portion of the box, an inner groove along a circumferential direction is provided, and some threads of the inner male threaded portion of the pin are contained in the inner groove.

Abstract: A coupling for connecting downhole tubulars includes a tubular body, and at least one thread of a male screw thread formed on an outer surface of the body, and a female screw thread formed in an inner surface of the body. The at least one thread has a thread-form including a crest, a root, and a pair of flanks. The crest and the root are each cambered about a respective first and second camber radius. Each camber radius is greater than an outer diameter of the coupling.

Abstract: An implant device (100d) for engagement with a bone of a subject, said the implant device (100d) comprising a distal end (102d), a proximal end (104d), a central shaft (106d), a longitudinal central axis (108d) and a helical thread portion (110d) having a leading edge (114d) and a trailing edge (116d). A portion of the leading edge (114d) extends in a direction towards the distal end (102d) of the implant further than the most distal portion of the root (112d) of the thread portion (110d); and wherein the trailing edge (116d) extends in a direction of from the most proximal portion of the root (112d) in a radial outward direction and towards the distal end (102d); and a crest portion (118d) disposed between the leading edge (114d) and the trailing edge (116d) and wherein said the crest portion (118d) forms a radially outward portion of the thread portion (110d). Hence, the implant device (100d) improved the axial pull-out strength and reduced stress concentration.

Abstract: A system for connecting a drill bit and pipe puller to a drill string. The system includes a downhole tool having an internal cavity and a through-hole in its wall. A coupler may be slidingly received in the cavity and connected using one or more fasteners which interconnect a groove in the coupler to the wall of the downhole tool. Fasteners used may be screws or bolts interconnecting the wall of the tool with radial holes in the coupler. Alternatively, bolts may interconnect the wall with a circumferential groove on the coupler. A drill bit may be threaded into the coupler. The coupler allows drill bits and other tools to be connected and disconnected from a downhole tool without unthreading the drill bit.

Abstract: A sensor-on-clamp device for use in a drilling system, the clamp being a tool joint clamp and houses one or more sensors mounted to the tool joint clamp, a power source and sensor data transmitting means. One or more sensors for use in a drilling system, said sensors being powerable by a single commercially available, replaceable battery.

Abstract: Described are systems and methods for evaluating the leak safety of threaded connections in well tubulars. A method, for example, includes assessing leak risk according to a Leak Criterion with Thread Shear. The Leak Criterion with Thread Shear is a function of the conditions relative to a pin-box interface radius and includes two constants: a Thread Modulus (alpha) and a Makeup Leak Resistance (beta). The leak risk is evaluated at the pin-box interface and is a function of differential pressure, effective stress, and shear stress. Lab tests conducted under known conditions are described for calculating the constants, alpha and beta, which are independent of extrinsic states or conditions.

Abstract: A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

Abstract: A threaded pipe connection includes a first tubular member having a pin end defining external threads, a second tubular member having a box end defining internal threads threadably engageable with the external threads of the pin end, and a thread profile that defines at least a portion of one of the internal or external threads and includes a crest, a root, and a transition surface extending between the crest and the root. The transition surface includes a first arcuate surface extending from a top of the crest at a first radius, a second arcuate surface extending from the first arcuate surface at a second radius, and a third arcuate surface extending from the second arcuate surface at a third radius. The first radius and the third radius are each smaller than the second radius.

Abstract: Disclosed herein are aspects of a barrier coating layer of an expandable member wellbore tool for use in a wellbore. The barrier coating layer, in one aspect, covers at least a portion of the outer surface of the expandable member and has a composition formulated to react with a wellbore fluid and erode within a predetermined amount of time to allow a wellbore fluid to contact and hydrolyze the expandable member.

Abstract: A tube connection for connection to a tube includes: a body having a through hole with a central axis, a first end, a second end, and an internal thread arranged close to the first end and coaxial with the central axis. The internal thread has a constant pitch diameter. A maximum diameter of the internal thread increases in an axial direction from the first end towards the second end. A minimum diameter of the internal thread decreases in the axial direction from the first end towards the second end.

Abstract: A threaded joint includes: a pin having an annular outer peripheral surface portion formed on a tip end side of a steel pipe, and an externally-threaded portion formed from the annular outer peripheral surface portion toward a center of a steel pipe in an axial direction of the steel pipe; and a box having a cavity in which the pin is housed, wherein an internally-threaded portion which threadedly engages with the externally-threaded portion and an annular inner peripheral surface portion which is brought into contact with and abuts against the annular outer peripheral surface portion are formed in the cavity, wherein the pin and the box are joined to each other due to threaded engagement between the externally-threaded portion and the internally-threaded portion.

Abstract: A drilling tool for use in a wellbore comprises a first collar having a first bore extending from a first send to a second end and an internal thread disposed on the bore at the second end. The drilling tool also comprises a second collar having a second bore extending from a third end to a fourth end and an external thread disposed on the third end. The third end is coupled to the second end of the first collar. A first set of components is housed within the first bore and a second set of components is housed on a sidewall of the second collar formed between the second bore and an outer surface of the second collar.

Abstract: There is disclosed a threaded joint for coupling together rods, tubes, pipes etc. The joint consists of helical box and pin thread segments each defined by a pressure flank and a clearance flank spaced apart from each other with alternating roots and crests. The pressure flank is defined by an S-curve extending between the root and the crest, which is defined by a first curvature c1 adjacent to the root and a second curvature c2 adjacent to the crest. c1 and c2 curve in opposing directions with an inflection point “i” between curvatures c1 and c2.

Abstract: An elongate component, such as a drill rod or adaptor, forms part of a drill string having a shoulder contact male spigot coupling. The male spigot includes a non-threaded shank and a threaded section in which an axial length of the non-threaded shank is provided at a predetermined minimum relative to an outside diameter of the spigot at the threaded section.

Abstract: A threaded connection for steel pipe is provided that prevents galling on the sealing surfaces during make-up while providing high sealing performance after completion of make-up. The pin (10) includes a nose (112) including a pin taper guide surface (112a) and a pin sealing surface (113) including a taper surface (113a). The box (20) includes a nose-receiving portion (22) including a box taper guide surface (22a), a box sealing surface (23) including a taper surface (23a), and a buffer surface (24). The taper angle of the taper surfaces (113a, 23a) includes a second taper angle larger than the taper angle of the taper guide surfaces (112a, 22a). The threaded connection (1) is constructed so as to satisfy Dp2>Db2>Dp1 and Lb2>Lp2. The buffer surface (24), located between the box taper guide surface (22a) and taper surface (23a), has a length of 0.75 mm or larger, and is located outward of an imaginary plane (V) determined along radial directions.

Abstract: A composite torque pipe to metal fitting joint including concentric inner and outer shells formed with respective smooth conical surfaces projecting distally and respectively tapered radially inwardly and radially outwardly to form an annulus expanding in thickness for receipt of a tapered connector ring complementally shaped at one end of a composite pipe and bonded along the interface. The present invention includes selecting the sleeves with the corresponding shells and, forming the torque pipe with the tapered ring and bonding the tapered ring in the annulus.

Abstract: A threaded product is provided having an external thread form on a tubular pin member comprises load and stab flanks on either side of a crest, along with smooth transitions between the crest and flanks. An elliptical root between the flanks aids in reducing stress and forms a dope volume between a non-conforming crest of an internal thread form of a tubular box member. Flanks of the internal thread of the box member contact flanks of the external thread of the pin member to form areas of mating contact on either side of the thread.

Abstract: A connector for connecting pipes and for use with power tongs have a die length. The connector includes a body with threaded connection portions at each end of the body on an inside surface of the body. The connector includes a gripping surface defined on an outside surface of the body between the threaded connection portions. The gripping surface is at least as long as the die length. The connector includes a reinforced portion of the body proximate each of the threaded connection portions for increasing resistance to deformation of the body upon being connected with a pipe. The gripping surface and the reinforced portion together facilitate an increase in connection torque of pipes connected with the connector.

Abstract: Method for manufacturing a composite tube having at least one double-layered portion with an annular outer layer of a first alloy and an annular inner layer of a second alloy provides a base component of the second alloy, having a central through-hole and an externally threaded section, provides an outer component of the first alloy, having an internally threaded section configured to engage with the externally threaded section, forms a tubular work piece by mounting the outer component around the base component such that the internally threaded section is in engagement with the externally threaded section, and hot works the work piece so that a metallic bond is formed between the threaded sections while the mechanical interlock is maintained, and so that the work piece is elongated and its outer diameter is reduced, thus forming a composite tube.

Abstract: An expandable connection is configured such that a metal-to-metal seal is created upon expansion, even under different expansion ratios. The creation of the metal-to-metal seal can rely on a spring-back effect after expansion. A high pressure rating of the metal-to-metal seal that is created can be achieved with an oversized box face thickness. The expandable connection can also be configured to achieve a high tensile efficiency.

Abstract: A threaded coupling suitable for drilling oil and gas wells is provided. The threaded coupling having a first end and a second end. A first portion of the threaded coupling proximal to the first end can have a first thread profile, and a second portion of the threaded coupling proximal to the second end can have a second thread profile that is different from the first thread profile. In particular, at least two threads of the second thread profile proximate to the second end are reduced in height according to an extra machining angle. The first thread profile and the second thread profile can further be tapered according to a taper angle.

Abstract: An assembly of a drug delivery system, comprising: a first component; a second component which is configured to move linearly with respect to the first component; and, a resistance element configured to resist linear movement during transport of the first component with respect to the second component in a closed transport configuration but which is adapted to be overcome during nominal operation of the drug delivery system.

Abstract: An inflating stick and a processing machine are provided. The inflating stick includes a body, a link rod, a cutter, and one or more inflating tubes. A front end of the body includes a guiding segment with a cone structure. A rear end of the body includes a packing segment. The body includes a gas inlet formed on the packing segment, an internal chamber allowing gas to flow into through the gas inlet, and gas outlets formed on an outer wall of the body allowing gas to flow out. The packing segment includes a first locking structure and a second locking structure. The first locking structure and the second locking structure communicate with the gas inlet. The second locking structure is detachably fastened to the first locking structure. The link rod and the cutter are disposed in rear of the body. The inflating tube is connected to the gas inlet.

Abstract: Provided is a threaded joint for an oil well tubing which possesses sufficient sealability when the external pressure is applied to the threaded joint by suppressing the plastic deformation of a nose portion and sufficient galling resistance. The sufficient galling resistance is provided by preventing the occurrence of galling at the time of making up the threaded joint during verification test performed in accordance with ISO13679:2002 even when the threaded joint for an oil well tubing has a small thickness. Parameters including sizes of the threaded joint at positions of a seal point and shoulder portions satisfy formula 1 ((Ds12?Ds02)/(D12?D02)?0.30), formula 2 (tan ?>(?D+?)/{2(Lt?Ls)}), and Ls/Ln is set to 0.2 to 0.6.

Abstract: A threaded connection for steel pipe with improved sealing performance is provided. A threaded connection (1) for steel pipe includes a pin (10) and a box (20). The outer diameter of the box (20) is smaller than 108% of the outer diameter of a steel-pipe body (30). The pin (10) includes a pin lip (12) including a first seal surface (11), a male thread (13) constituted by a single-stage tapered thread, and a second seal surface (14). The box (20) includes a first seal surface (21), a female thread (23) constituted by a single-stage tapered thread, and a box lip (22) including a second seal surface (24). When assembled, the first seal surfaces (11, 21) are in contact with each other and the second seal surfaces (14, 24) are in contact with each other. A portion of the male thread (13) located near the end thereof close to the pin lip (12) includes a plurality of thread root surfaces extending parallel to the pipe axis (CL) and having the same diameter.

Abstract: A flush joint high torque thread that achieves superior tensile efficiency and compression efficiency. In one example, the thread of a pin member and a box member includes a thread a chamfer with angled shoulders on each side of the thread to minimize radial plastically deformation of the shoulders. The stab flanks each contain a lead-in taper extending no further than a thread pitch line from the thread crest. The load flanks are each perpendicular. The stab flanks engage each other during assembly, but not upon assembly. The load flanks do not engage each other during assembly, and do engage each other upon assembly.

Abstract: An electromagnetic shield component that includes a first tube that has conductivity; a flexible shield; and a second tube externally fitted to the first tube with the flexible shield disposed between the first tube and the second tube, wherein: a protrusion is provided on an inner circumferential surface of the second tube over an entire length of the inner circumferential surface in a circumferential direction, the protrusion protruding toward the flexible shield and holding the flexible shield in a pressed state between the first tube and the second tube, and an outer circumferential surface of the protrusion is smoother than an outer circumferential surface of a portion of the second tube where the protrusion is not formed.

Abstract: A marine riser having a pressure level rating of twenty ksi or more includes riser tubulars and auxiliary lines that are made of steel having an API grade C110 and C125 and is NACE certified. The riser tubulars and auxiliary lines are not welded, but are assembled via threaded, clamped, stabbed or other mechanical and/or hydraulic connections. Some of the connections may be pre-assembled to reduce assembly time on the drill ship.

Abstract: A method of conducting a surgical procedure including implanting an anchor into a bone, wherein the anchor comprises a receiving portion and a screw, the screw including a screw head contained within the receiving portion and pivotally engageable with a surface of the receiving portion, and wherein the receiving portion and the screw comprising a different material. The method further includes selecting a rod from a group of rod types and coupling the rod with the receiving portion to stabilize a position of a portion of the spine.

Abstract: The invention relates to an apparatus and a method for joining extended lengths of conduit. The apparatus and method provide a means for decreasing the time required to assemble extended lengths of conduit. The apparatus for use with the corresponding method comprises an apparatus head, an extender joining body and a conduit interface.

Abstract: A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

Abstract: A thread structure in accordance to one or more embodiments includes a thread extending helically along a portion of a bit body in spaced thread turns, the thread having a crest extending between a first flank and a second flank and a root extending between the thread turns, the root having a curvature defined by a portion of an ellipse tangentially adjoining the first and second flank at respective flank transition points, the ellipse having a major axis extending parallel to the axis and a minor axis extending perpendicular to the major axis and through a root bottom.

Abstract: A pin-box well tubular connector assembly having pin and box connector members (6, 5) with intermeshing external and internal screw thread profiles is optimized for expansion downhole in a wellbore by: A) configuring the box connector member (5) such that it has at least one thread (10) that does not engage a thread on the pin member (6); and optionally: B) configuring the pin and box connectors (6, 5) such that in axial direction a gap of at least 0.2 mm is present between the external and internal screw thread profiles; and/or C) inserting a swellable dope in the gap between the pin and box connector members (6, 5).

Abstract: A threaded connection includes first and second tubular components, each including a respective male and female end. The male and female ends each include at least one threaded zone and finish in a terminal surface. The male threaded zone includes a first portion in which a width of teeth, CWTp, increases from a value CWTpmin corresponding to a width of a tooth closest to the terminal surface of the male end to a value CWTpmax corresponding to a width of a tooth furthest from the terminal surface. A width of teeth CWTb of the female threaded zone decreases from a value CWTbmax corresponding to a width of a tooth furthest from the terminal surface of the female end to a value CWTbmin corresponding to a width of a tooth closest to the terminal surface. The threaded zones cooperate in accordance with a self-locking make-up, with CWTpmin/CWTbmax?0.2 and CWTbmin/CWTpmax?CWTpmin/CWTbmax.

Abstract: In a pipe joint where two pipe sections (14, 16) have threadably engaged end portions (17, 18), joint ends (32, 34) are substantially sealed to each other by a sealing surface (40, 50) on one pipe section that substantially abuts a sealing surface (42, 52) on the other pipe section. In one joint, a ring-shaped cutout (121, FIG. 7) is formed in a first pipe section and a ring-shaped spacer (120) is located in the cutout. The spacer is chosen from several that have slightly different lengths so the spacer end contacts the corresponding sealing surface (130). In a pipe string used to carry corrosive fluid, the inner surface (44) of adjacent pipe sections is covered with a corrosion resistant coating (70, 72). Where the sealing surface is connected to a rounded corner (82, 84), the coating extends to and along the sealing surfaces (40, 42). Where there are sharp corners (80) at the intersection of the inside surface (40) with the sealing surface (40B, 42B), the coating does not extend along the sealing surfaces.

Abstract: Ends of separate tubular members used in oil and gas drilling are connected pin-to-pin by a threaded coupling and made leak tight by an internal pressure seal, wherein the male or field end pin of a first tubular member has an integral geometry designed to mate with the female or mill end pin of a second tubular member. The coupling and tubular members possess a modified buttress thread form having a negative load flank angle and a positive stab flank angle. When assembled, the coupling connects the field end pin of the first tubular member with the mill end pin of the second tubular member, wherein integral geometries of the mated pin ends generate the interference necessary to produce a single, metal-to-metal, leak-tight, internal contact pressure seal.

Abstract: A wheel nut indicator 10 includes an attachment section 12 for fitting to a wheel nut/lug nut of a wheel and a pointer section 14 extending radially away from the attachment section 12, the wheel nut indicator 10 being provided with a changeable secondary indication means which is moveable between a first position (FIG. 1) for indicating a first status, and a second position (FIG. 3) for indicating a second status.

Abstract: A tubular coupling system and method; the system and method in at least certain aspects, using a coupling member with an interior protective ring that has at least one inner energizing member which, upon compression, forces the body of the coupling member against an interior wall of the coupling thereby inhibiting corrosive material from contacting the coupling's interior wall or, in the event some corrosive material does enter this area, holding the interior protective ring against the coupling's interior wall so that the corrosive material remains in and does not exit this area, thus inhibiting or preventing a continuous flow of corrosive material.