Sealing System for Joints
A gasket and seat system for sealing a joint is disclosed. The gasket comprises, for example, an inner portion with a wall facing an interior of the coupling and an outer portion, which extends axially forming radial end walls. The inner portion of the gasket is formed with an angled wall, making the inner portion expand inwards, which angled wall interacts with a matching angled wall of the seat, such that the joint has provisions for increasing the sealing ability in cases with increased pressure in the coupling. The gasket may further have the wall facing the interior being adapted to be flush with an interior surface when mounted in the seat and may also have provisions for heat expansion and elevated pressures, in order to remain flush with the coupling at elevated temperatures and in order to ensure sealing at elevated pressures.
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This application is a continuation of U.S. patent application Ser. No. 11/666,743, filed Jun. 6, 2008, which is a 371 application of PCT/SE05/01388 filed Sep. 21, 2005.
FIELDThe present invention generally relates to a sealing system for substantially immovable joints of two elements, and more specifically to a gasket and seat system for sealing between substantially immovable joints such as flanges, tube or pipe couplings, housings, shafts, etc. Preferably, the system provides a hygienic sealing with a smooth surface to a product provided within the joint elements and which also handles volumetric changes in the rubber caused by temperature changes, and preferably the system provides a sealing that in addition tolerates increased pressure conditions on the sealing system without degrading its sealing performance.
BACKGROUNDA gasket and seat system of the kind described above is for example shown in DE-A-42 01 535. The sealing according to this system will provide a gasket being flush with the interior surfaces of the pipes and it has some provisions for heat expansion.
Gasket and seat systems that provide gaskets flush-mounted with the interior surfaces of pipes are for example desired in the pharmaceutical and food industry. For instance, the ISO 2852 standard of 1993 defines stainless steel pipe couplings for the food industry, wherein a gasket is disclosed as a ring-shaped pipe coupling part intended to make a hygienic liquid-tight joint between the flanges of two clamp liners. This kind of sealing system is intended to prevent residue and bacteria from accumulating in pipe joints, especially e.g. in crevices of the sealing system. The pipes of these facilities are regularly cleaned by CIP (Cleaning In Place) and SIP (Sterilization In Place) with hot steam (140 C) in order to kill bacteria that may be present in the pipes. This means that the gaskets must be able to handle heat expansion while remaining flush, or almost flush, with the interior surfaces of the pipes even during steam washing. If the gaskets project from the pipe interior, they can further induce turbulence in the pipes and this may be unwanted in some cases. The gasket disclosed in ISO 2852 does not have provisions against such expansion into the pipe interior caused by a difference in the expansion coefficients of the pipe material and the gasket material. Furthermore, the same problem applies to other types of joints than pipe couplings, having similar sealing purposes, for instance a heat exchanging system for heating a product inside a pipe. In this case different operating temperatures cause a different amount of expansion during operation. The sealing has to cope with these varying operating conditions without causing undesired crevices, as explained above.
With a gasket and seat system of the known kind, there is no provision for improving the sealing ability during periods with increased pressure in the pipes. The gasket inner portion is also rather large, which increases the risk of this portion expanding, due to increased heat, into the interior of the pipes. Since the gasket furthermore is symmetrical, machining is necessary in both parts of the coupling in order to form an appropriate seat. The same problems occur with known gasket and seat systems for similar couplings, e.g. in pump housings of food pumps.
Hence, there is a need for a more advantageous sealing system.
SUMMARYIt is an object to solve at least the above problems, singly or in any combination, by arranging a gasket and seat system which provides a gasket for a joint, such as a coupling or union of similar elements, such as flanges, tube or pipe couplings, housings, shafts having attached elements thereto, etc, and which has provisions for increasing the sealing ability in cases with increased pressure in the joint, such as a pipe or a coupling.
This object is obtained by the features of the various aspects shown as defined in the attached claims. Particular embodiments are given in the dependent claims. In an embodiment, the gasket may have a wall facing the interior being adapted to be flush with an interior surface when mounted in a seat and may also have provisions for heat expansion, in order to remain flush with the joint elements, as e.g. a pipe or a coupling, at elevated temperatures. Moreover, a pressure applied on to the gasket improves the sealing capability of the gasket and seat system by tightening the gasket using the hydraulic force pressing onto the gasket for improved sealing of the gasket against the counter faces. The gasket may furthermore be self-retaining inside the seat, which simplifies the procedure of coupling the joint elements, e.g. pipes or union elements. In another embodiment, the seat is only formed in one part of the joint, e.g. in one pipe or flange, thus reducing the amount of machining necessary. Yet another embodiment may have a silver ion coating on the gasket for obtaining antiseptic properties.
More particularly, according to one aspect, a gasket and seat system suitable for sealing a joint is provided. The gasket may be made of a polymeric material comprising an inner portion, with a wall facing an interior of the joint, and an outer portion, which extends axially forming radial end walls, wherein the inner portion of the gasket is formed with an angled wall, making the inner portion expand inwards, which angled wall is configured to interact with a matching angled wall of the seat.
The wall facing the interior of the joint may be adapted to be flush with an interior surface of the joint when mounted in the seat, thus providing a hygienic interior surface not susceptible for contamination.
The wall facing the interior of the joint may be angled slightly inwards from a common point of engagement for the interior surface and the wall. Furthermore, the gasket may be formed with a groove in the outer portion thereof, and may be formed with angled walls of the outer portion which are compressed upon entry in the seat.
A gasket surface facing a flange plane may be adapted to be flush with the flange plane after assembly.
The gasket may comprise silver ions, in order to obtain antiseptic properties.
The joint may be a pipe coupling that may comprise two flanges, wherein the gasket may be located in one of said flanges only, preferably pre-mounted in said one flange during assembly of said system.
The joint may be comprised in a pump housing of a pump for food processing or pharmaceutical product processing. According to a further aspect of the invention, a gasket of polymeric material is provided, which gasket is adapted to seal a joint comprising an inner portion, with a wall in use facing an interior of said coupling, and an outer portion, which extends axially forming radial end walls, wherein the inner portion of the gasket is formed with an angled wall, making the inner portion expand inwards, which angled wall is configured to interact with a matching angled wall of the seat.
The polymeric material of the gasket may be elastic and resilient and may comprise rubber materials such as EPDM, Viton®, VMQ, FPM, FKM and HNBR, thermoplastic materials, or compositions comprising such materials singly or in combination.
According to yet a further aspect of the invention, a gasket and seat system as mentioned above, according to the above-mentioned aspect of the invention, is used for hygienically sealing a joint comprising a coupling in a union of coupling elements adapted for food or pharmaceutical processing. According to another aspect of the invention, a method of assembling a gasket and seat system for sealing a joint according to the above-mentioned aspect of the invention is provided. The method comprises pre-mounting the gasket in one element of the joint, wherein said element comprises said seat, such that assembly of said system is facilitated.
The invention will be described in further detail below with reference to the accompanying drawings, in which:
A gasket 1, in the present embodiment in the form of a form ring or sealing ring, and seat 2 of an embodiment of the present invention can be seen in
An enlarged view of the gasket 1 is shown in section in
In
When the gasket 1 of
When the gasket 1 and seat 2 of the above description are subjected to heat, they will expand. However, the thermal expansion of rubber is about seven times as high as that of metal. Therefore, the groove 14 of the gasket's 1 outer portion 11 allows for compensation of this expansion difference and this minimizes the expansion of the gasket 1 to the interior of the pipe. The main purpose of groove 14, when the gasket 1 is assembled in the flange 3 is to compensate for this expansion during thermal changes. Furthermore, the expansion of the gasket inner portion 10 is reduced due to its small size.
An increased pressure in the pipe will lead to an increased sealing pressure of the gasket 1, both axially and radially, since the inwardly expanding inner portion 10 is self-engaging. The pressure against the innermost surface 17 will force the inner portion 10 inwards increasing the pressure between the angled walls 18 and 25, thus improving the sealing ability. Hence, such a pressure applied onto the gasket improves the sealing capability of the gasket 1 and seat 2 system by tightening the gasket 2 using the hydraulic force caused by the pressure and pressing the gasket tighter into its counter sealing surface for improved sealing of the gasket against the counter faces. The inwardly expanding inner portion further reduces the tendency of outward radial displacement towards the outer portion, caused by an increased pressure in the pipe. The above gasket 1 now seals the flange coupling without presenting any cracks, crevices or protrusions to the interior of the pipe.
The gasket of the present invention may, as mentioned above, be mounted in a hollow joint, such as a pipe flange coupling, only requiring machining in one side of the flange surfaces. The gasket is further self-retaining, which simplifies assembly. This is both cost- and time-effective. Moreover, the gasket provides a way of sealing two pipes, or similar couplings such as two joined elements of pump housings, without presenting any edges or cracks to the interior of the pipe or the coupling, even if the temperature is increased to about 140 C.
The gasket of the present invention may be manufactured from different kinds of polymeric material having elastic and resilient characteristics, e.g. rubber materials such as EPDM, Viton®, VMQ, FPM, FKM and HNBR, thermoplastic materials, or compositions comprising such materials singly or in combination. Care should be taken so the chosen material does not affect the contents in the pipe. If desired, the gasket may be provided with further advantageous properties, for instance it may be covered with a suitable coating, e.g. a silver ion coating if the gasket is to be antiseptic. Further, such materials as e.g. silver ions may be homogenously distributed in the gasket material in order to provide the desired properties. This is advantageously achieved by mixing such additives into the gasket material or by coating the gasket prior to forming and curing the same or by coating the gasket prior to curing the polymeric material. The right hand surface 19 of the gasket 1 is illustrated as being planar, but this is not necessary. If a certain compression of the rubber is wanted, this may be achieved by incorporating a specific profile in this surface 19, which though will be planar after assembly, so that machining of only one part of the coupling for fitting the gasket is necessary.
The overall shape of the gasket is determined by the shape of the joint, e.g. a pipe coupling, and the gasket will be formed to follow the interior surface of the pipe. In
The gasket and seat system of the present invention is shown in a pipe coupling with parallel interior walls, but may just as well be mounted in conical couplings or joints. It may be used in flange couplings, housings of pumps (see example below), pipe fittings, tube fittings, pipe couplings, and/or union couplings. It may also be used for dairy fittings, joined houses, e.g. of a pump, mechanical sealings, or similar as is evident to a person skilled in the art. The gasket and seat system of the present invention may also be used in heat exchangers, especially in the food and pharmaceutical industry. Non-limiting examples of pump housings are for instance a housing of an eccentric screw pump, which may use a gasket as shown to the right in
The gasket and seat system may also be arranged in a housing 60, for sealing off e.g. a shaft 61 having mounted thereon a shaft mounted element, see
Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.
Claims
1. A gasket and seat system suitable for sealing a joint, wherein the gasket is made of a polymeric material, said gasket comprising:
- an inner portion having a wall forming an inner diameter of the gasket, the wall in contact with an interior and high pressure side of the joint, and
- an outer portion, arranged radially outside said inner portion, and said outer portion extends axially forming radial end walls,
- wherein the gasket is formed with a groove in the outer portion between said radial end walls, wherein said radial end walls are compressible towards the groove for fitting into said seat.
2. The gasket and seat system according to claim 1, wherein the wall facing the interior of the joint is adapted to be flush with an interior surface of the joint when mounted in the seat.
3. The gasket and seat system according to claim 1, wherein the wall is angled slightly inwards from a common point of engagement for an interior surface.
4. The gasket and seat system according to claim 1, wherein the inner portion of the gasket is formed with an angled wall connected at the wall and at one of the radial end walls so that the wall and angled wall are contiguous surfaces forming an angle, whereby the inner portion increases in breadth from the outer portion to the wall in contact with the interior and high pressure side along the angled wall, wherein the angled wall parallels a matching angled wall of the seat.
5. The gasket and seat system according to claim 1, wherein the gasket is formed with angled walls of the outer portion which are compressed upon entry in the seat.
6. The gasket and seat system according to claim 1, wherein a gasket surface facing a flange plane is adapted to be flush with the flange plane after assembly.
7. The gasket and seat system according to claim 1, wherein the gasket comprises silver ions, in order to obtain antiseptic properties.
8. The gasket and seat system according to claim 1, wherein said joint is a pipe coupling.
9. The gasket and seat system according to claim 8, wherein said pipe coupling comprises two flanges, wherein the gasket is located in one of said flanges only, preferably pre-mounted in said one flange during assembly of said system.
10. The gasket and seat system according to claim 1, wherein said joint is installed in a pump housing of a pump for food processing or pharmaceutical product processing.
11. A gasket of polymeric material adapted to seal a joint, said gasket comprising:
- an inner portion with a wall forming an inner diameter of the gasket, wherein the wall is in contact with an interior and a high pressure side of said joint when in use, and
- an outer portion, which extends axially forming radial end walls, wherein the inner portion of the gasket is formed with an angled wall connected at the wall and at one of the radial end walls such that the wall and the angled wall are contiguous surfaces forming an angle, whereby the inner portion increases in breadth from the outer portion to the wall in contact with the high pressure side.
12. A gasket of polymeric material adapted to seal a joint, said gasket comprising
- an inner portion, with a wall forming an inner diameter of the gasket, wherein the wall is in contact with an interior and a high pressure side of said joint when in use, and
- an outer portion, which extends axially forming radial end walls, and wherein the outer portion comprises a groove between the radial end walls, wherein said radial end walls are compressible towards the groove for fitting into a seat.
Type: Application
Filed: Oct 2, 2012
Publication Date: May 1, 2014
Applicant: HUHNSEAL AB (LANDSKRONA)
Inventor: HUHNSEAL AB
Application Number: 13/633,163
International Classification: F16L 23/16 (20060101); F16J 15/04 (20060101);