MXPA00012530A - Pipe gasket with embedded ring - Google Patents

Abstract

A pipe sealing gasket (45) is shown which is designed to be received within a groove (43) provided within a socket end of a thermoplastic pipe (47). The gasket has a ring shaped body of an elastomeric material and includes a metal reinforcing ring (55). The elastomeric body includes a first portion of relatively low durometer rubber (46) and a second portion of a relatively high durometer rubber (48). The regions of relative hardness and the placement of the reinforcing ring assist in retention of the gasket during the pipe belling process and in field installation.

Description

PIPE JOINT WITH ASSEMBLED RING Description Technical Field The present invention relates generally to sealing joints used for pipe joints in which the male pipe section is installed within an egg section of the female coupling pipe.

Background of Art Pipes formed of thermoplastic materials including polypropylene polyethylene and PVC are used in a variety of industries. When forming a joint between sections of a pipe, the male end of the pipe is inserted into the female or end of the pipe socket. An annular, elastomeric or gasket ring is typically located within a groove formed in the socket end of the thermoplastic pipe. As the male end is inserted into the gap, the joint provides the greatest sealing capacity for the joint. It is critical during installation of the process that the joint can not be twisted or shaken as a dislocated or misplaced joint will adversely affect the final sealing ability of the joint. Regardless of the type of sealing action of the sealing element, such as the compression sealing action, lip sealing action or combination thereof, it is necessary that the sealing gasket consist of a relatively soft elastomeric material. However, a sealing ring formed entirely of a material that is sufficiently soft and elastomeric to provide the sealing function has the disadvantage that it is difficult to remain in the desired position in a slot connected with the connections of the sections of the pipe. There is also a risk that said sealing ring will be displaced from its sealing position at the pipe junction if the difference between the external and internal pressures on both sides of the sealing ring is sufficiently large. In the early 1970s, a rogue technology was developed by Rieber & They are from Bergen, Nor ay, referred to in the industry as "Rieber Joint". The Rieber system employed a combined mold element and a sealing ring to seal a joint between the end of the socket and the male end of the two pipes formed of thermoplastic materials. In the Rieber process, the elastomeric gasket was installed within an internal groove formed simultaneously at the socket end of the female pipe during the pipe forming process. The supply of a pre-compressed and ellomeric gasket secured during the pipe factory formation process provided an improved fitting end for joining the pipe with a seal that would not twist or loosen or allow impurities to enter the zones. of sealing of the joint, in this way the safety of the joint is increased and the risk of losses or possible faults due to wear is reduced. The Rieber process is described in the following patents of the United States of North America granted among others: 4,120,521; 4,061,459; 4,030,872; 3,965,715; 3,929,958; 3,887,992; 3,884,612 and 3,776,682. It should be evident that the sealing ring of the type under consideration can be manufactured entirely from an elastically malleable material, such as rubber. Such a design would be simple and could be produced relatively easily with simple production equipment. However, as has been discussed, such sealing rings made entirely of elastically malleable material generally lack the support effect to avoid being released during field installation procedures and may not be suitable for use as a combined mold element, as described above. The slot provided at the end of the socket or tubing can take several forms. The problem of containing the sealing rings during the joints of the pipes is even more important in the case where the female groove has a lower surface which is at least partially rounded. In these cases, the forces directed to the shaft can create a substantial twisting inside the sealing ring. In order to study the aforementioned problems, different approaches have been suggested to compensate for the lack of support effect in the sealing rings made of elastically malleable material. The patent of the United States of America no. 3,776,682 mentioned above utilizes a separate support member to support the mold member in producing the fitting end of the pipe. However, the construction is more or less lacking in support as a sealing ring. The Patent of the United States of North America does not. 3,500,047 shows a design using two mold element support rings connected to a sealing ring. However, a design that has the characteristics of having three separate parts complicates the manufacturing operation. In other designs, the sealing ring, in addition to the elastically malleable material, includes either an external or internal containment ring or a band intended to hold the joint during the manufacturing operation and / or during the field and transport installation procedures. .In those designs that use external reinforcing bands or rings, it is possible that water, sewage or other contaminations may corrode metal surfaces, thereby compromising the integrity of the pipe joint. It is an object of the present invention to provide a sealing gasket of an elastically malleable material whose use as a combined mold element and sealing ring is suitable. Another object of the present invention is to provide a seal with a reinforcement region that helps ensure that the joint is not displaced during field installation, storage or transportation and that it serves as a reinforcing contact point during the operations of training. Another object of the present invention is to provide a seal that incorporates both the reinforcing member and the reinforced region of the joint material itself to thereby utilize both types of reinforcement actions in a combined mold and sealing element. Another object of the present invention is to provide a sealing gasket having an externally exposed region of a material that is different from the rest of the body of the gasket, the colored reinforced region to identify the type, end use or other characteristics of the gasket. board.

Another object of the present invention is to provide such a joint design with an embedded metal ring which prevents the metal from coming into contact with the water and which at the same time provides a reinforced contact point for the reinforcement of the joint during the operations of molded combined.

Disclosure of the Invention In joining the pipe of the invention, a first pipe of thermoplastic material has a fitting end that includes an internal annular groove and inner cylindrical surfaces on both sides of the groove of a substantially equal diameter. A second pipe has an insertion end which is installed inside the fitting end of the first pipe. "A seal is disposed within the groove completely within the cylindrical surfaces concentrically between and sealing the insertion end of the pipe and the fitting end of the pipe.The seal is an elastomeric body having a first portion of an relatively low durometry gum to provide the necessary sealing action and having a second portion of a relatively high durometry gum The joint also has a rigid ring reinforcing continuous girth and in the form of a circle located within the second portion of a relatively high durometry gum The joint possesses a first portion which, when viewed in cross-section, includes a narrow entry surface on an inner surface thereof which tapers downward to form a lower compression region to form the compression seal with the insert end of the male end when joining the pipe In a preferred form, the second portion of the gasket has an exterior defined by a straight portion, when viewed in cross-section, which is inclined in relation to the longitudinal axis of the pipe and which directly contacts the internal groove of the pipe. The pipe. The rest of the outside of the joint consists of a first portion of lower durometry rubber that occupies the rest of the annular pipe groove. In the method of installing the pipe joint within the groove in the female section of the thermoplastic pipe, a sealing gasket is first installed in a forming mandrel and placed against a forming stop ring. A section of a thermoplastic pipe is heated and an orifice region thereof is forced onto the gasket previously installed in the forming mandrel to thereby deform an inner surface of the heated pipe. The section of the pipe is separated from the stop ring in formation in such a way that the heated pipe contracts the joint with the deformed inner surface comprising a joint groove in the opening of the pipe. The pipe is then removed with the previously installed joint of the mandrel in formation. The gasket is an elastomeric body having a first portion formed of a relatively lower rubber to provide the necessary sealing action and having a second portion of a relatively high durometer gum. The gasket also comprises a circumferential and continuous reinforcing ring located entirely within the second portion of a relatively high durometer gum. Additional objects, characteristics and advantages will be obvious in the written description that follows.

Brief description of the Drawings Figure 1 is a partial perspective view, partially fractured showing the union of the pipe of the invention in which the end of the male pipe is inserted inside the end of the female pipe, the end of the female pipe has a groove to receive the sealing gasket of the invention; Figure 2 is a cross-sectional view of the juTta of the invention showing the fitted ring and different regioies of elastomeric material thereof; Figure 3 is a cross-sectional side view of the female end of the pipe showing the gasket of the invention at the male end in the compressed manufactured state indicated by the cut lines; and Figures 4-7 are simplified schematic illustrations of the prior art of the Rieber process for the installation of a seal within a groove formed within the female end of a thermoplastic pipe.

The Best Way to Carry Out the Invention In order to fully appreciate the advantages provided by the pipe joint of the invention, the prior art of the manufacturing process of the invention must be taken into account first.

Rieber Turning first to Figures 4-7, the Rieber process is illustrated by showing the installation of the compression seal of the prior art within the slot provided within the female end of the pipe section. Figure 4 shows an elastomeric sealing gasket 11 having an exposed reinforcing band 13, the gasket being shown installed on the generally cylindrical external part of the working surface 15 of the mandrel 17 used in the forming process. The elastomeric seal 11 can be formed of, for example, rubber and is a ring in the form of a circumferential member having a lower compression region 19 and an exposed front portion 21 which, as shown in Figure 4 splices a support or ring stop 23. The stop ring in formation 23 has a first generally cylindrical extension 25 which is joined to the second cylindrical measure 27 by means of a stepped region 29, where the first extension 27 is of a greater external diameter than the first extension cylindrical 25, as shown in Figure 4. In the prior art technique, the reinforced steel elastomer ring 11 is located on the working surface of the mandrel 17 and is pushed into a position against the mounting or stop ring in formation 23. In this position, the joint is firmly anchored to the mandrel surface. In the second step of the process, the female end 33 of the thermoplastic pipe 31 is heated and pushed onto the steel mandrel 17, the gasket 11 and the stop ring holder 23. The female end expands due to the thermoplastic nature of The pipe. A number of thermoplastic materials such as polyethylene, propylene and polyvinyl chloride (PVC) are known in the prior art which possesses the required expansion characteristics, depending on the final application of the pipe joint.

The female end 33 flows over the first cylindrical extension 25 of the support stop ring 23 and splices the stepped region 29 into the second process step. In the next step of the process (Figure 6) the mandrel and the pipe move from the support stop ring 23 and the female pipe end 33 retracts around the mandrel and the gasket 11 due to the elastic forces of the thermoplastic material. Typically, vacuum is also applied through the ports 35,37 which connect the mandrel work surface to the vacuum source (not shown). In the last step of the process (Figure 7) the female pipe end 33 is cooled by means of a water spray bar 38 and spray nozzles 41. While the cooling takes place, the female end of the pipe 33 contracts around of the gasket 11, then compressing the gasket body of the gasket between the steel reinforcement strip 13 and the female groove to thereby establish a firm seal. Because the seal is sealed against the female under controlled conditions in the factory, the possibility of sand or similar contaminants penetrating the crucial seal area of the joint is greatly reduced. The reinforcing metal band 13, in addition to providing the stiffness required during the described manufacturing process, also functions as containment to ensure that the gasket does not move from the groove (43 in Figure 7) during transport or installation. . The process described above for Rieber has taken place in commercial use since the beginning of the 1970s and is described in the aforementioned granted patents of the United States of North America, among other sources. Therefore, it will be known to those skilled in the art of sealing thermoplastic tubing. Figure 1 shows a sealing gasket of the invention, generally designated as 45 that is installed within the slot 43 within the female end 47 of the illustrated thermoplastic tubing.As shown in Figure 1, the inner annular groove 43 of the female end 47 is located within the cylindrical internal surfaces. 49, 51 of diameter ,, - substantially equivalent. The female end 47 is intended to be fabricated to form a pipe joint with the male pipe section 53 that is inserted into the female end 47. The seal 45, as shown in Figure 1, is located within the slot 43 by complete between cylindrical surfaces concentrically between and sealing the insertion end of the pipe 53 and the wound end of the pipe 47 (see Figure 3) when the joint is made. Figure 2 shows the gasket of the invention in an enlarged cross section for the illustration to be more 2 illustrative. The gasket 45 comprises a first portion 46 of a relatively more durometer gum. low and a second portion 48 of a relatively higher durometer gum. A rigid ring in continuous circumferential shape 55 is located within the body of the joint and fits within the region of the relatively higher durometer gage 48. The ring 55 is preferably formed of a rigid metal such as steel. The seal 45 includes a leading line region 57 and a lower compression region 59. The leading line region 57 is joined to the lower compression region 59 by means of the curvilinear conduction region 61 which forms an input surface Conical for the male end of the pipe that makes the pipe joint. The lower compression region 59 is also attached to the secondary sealing surface 63 by means of a rear curvilinear surface reaming 65 and a circumferential groove region 67. The groove region 67 includes an outer wall 69 that forms an obtuse angle with respect to the rest of the groove region. The secondary sealing surface 63 is a circumferential plane region terminating at an internal angle 71 of the joint 45. The internal angle 71 is connected to the outer angular region 73 of the joint 45 by means of the uniform extraction of the surface 75. of exterior joints. The outer angular region 73 is connected to the frontal region 57 of the joint by a concave curvilinear region 77.

As shown in Figures 2 and 3., the second highest dorometer portion of the joint 48 has an exterior defined by the straight portion 50 which, when viewed in cross section, is inclined in relation to the longitudinal axis (52 of the Figure). 1) of the pipe and directly contacting the groove of the inner pipe 43. The rest of the outside of the gasket comprises a first lower dorometer portion 46 that occupies the remainder of the annular pipe groove. The first relatively higher durometer portion of the joint 48 and the rigid reinforcement ring 55 are resistant to deformation so that the entire joint body is securely held in the groove of the end of the female pipe during the installation of the male end. Therefore, as shown in Figure 2, the secondary sealing surface 63 comprises a first extension 54 of the first relatively lower durometer gum and a second extension 56 of the relatively higher durometer gum. The internal angle 71 of the joint comprises the highest durometer gum in its entirety. The second portion of the joint 48, formed of a relatively higher durometry rubber, is generally rectangular in its cross section but ends in a wedge-shaped point that forms the internal angle of the joint.

The first portion of the body of the. gasket 46 is preferably formed of a synthetic or natural rubber a relatively lower durometry that is effective to provide a proper seal against the outer pipe groove 43. The second body portion of the gasket 48 may be formed of a less elastic material, harder, that has a higher durometry than the material of the first portion. Aurote various materials are known to have the requirement of being of higher durometry, such as plastic materials, 0 as plastic propylene or polyvinyl chloride plastic, the material, the preferred material for the second portion 48 is a synthetic or natural rubber of higher durometry to thereby provide a joint having a generally homogeneous composition. In a preferred embodiment of the invention, the second portion 48 is formed of a gum having a "Shore A" a durometry of the order of 75 to 95 while the first portion 46 is formed of a gum having a hardness "Srore A" "of the order of 40 to 65. Q The portions of the board 46,48 are entirely formations.

That is, they are bound or linked in some way along the angular lines which, in this case, form first leg 58 and a second leg 60 generally perpendicular thereto. The portions could be formed of, for example, extrusion, with the angular lines joining together by "gluing" or vulcanization to form a single joint body. Those skilled in the art of rubber making will also recognize that available techniques can be used to form a unitary body possessing regions of a different durometry. The second portion 48 of the seal body is preferably colored with suitable pigment to provide, for example, distinctive features for the end user. For example, a red band could indicate a gasket to be used in a water pipe, a blue band could indicate a gasket for use in sewage pipe, a yellow band could indicate a pipe suitable for use in high temperature application etc. . When referring to Figure 1, fabrication of the pipe joint requires the insertion of a section of male pipe 53 into the opening of the female end 47. A male end 53 passes over the joint region, the compression region 59 of the seal 45 comprises approximately the horizontal axis 93 (Figure 3). During the installation operation in which the male end 53 is inserted into the female end 47, the reinforcing ring 55 and the relatively higher durometer rubber region 48 help to hold the seal 45 in position within the groove 43, ensuring in this way that the board is not displaced or dislocated during the installation process.

Again referring to the prior art forming process in Figures 4-7 the joint of the invention 45 is first installed on the mandrel 17 in the a Leta identical to that of the prior art joint 11. As the pipeline heated 31 flows over the joint and is ultimately formed on the joint, the engaged ring 55 and the reinforcing region 48 together provide a reinforced contact point during the forming steps of the pipe groove illustrated in Figures 6 and 7. While the joint continues to provide a reinforced contact point to facilitate the forming operation, the metal reinforcement element is separated from the surrounding medium. Because the joints of the pipes of the invention are normally used in sewage or water transport systems, isolating the metal reinforcement element avoids any possible corrosion of the element that could adversely affect the integrity of the joint. An invention has been provided with several advantages. The board of the invention is simple in design and its manufacture is economical. The design is characterized by an elastomeric reinforced metal body that allows it to serve as a combined mold element and a sealing structure. In other words, the reinforced joint can be located in a forming mandrel with the heated thermoplastic tubing pressed on and around the joint to create a joint groove during the manufacturing operation without. that the board is dislocated. Additionally, the reinforcement element helps to maintain the joint in position once the forming operation is completed to ensure that the joint does not move or dislocate during storage, transportation or field installation. Because the reinforcing element is fitted within the elastomeric body of the gasket, it is completely insulated from the external environment including the water, drain and other fluids flowing through the junction of the pipe. As such, the metal reinforcement element is not subject to corrosion or deterioration by contact with liquids. The combination of a metal reinforcing ring and a reinforced elastomeric ring combine to improve the properties in their entirety of the combined sealing ring and a mold element. Although the invention has been shown only in one of its forms, it is not therefore limited but it is susceptible of several changes and modifications without departing from the spirit of the same.

Claims (19)

1. A pipe joint, comprising: a first pipe of thermoplastic material having a female end including an internal annular groove located along the central longitudinal axis and internal cylindrical surfaces on both sides of the substantially equivalent diameter groove; a second pipe having an insertion end that couples with the male end of the first pipe; a sealing gasket disposed within the groove completely between the cylindrical surfaces concentrically between and sealing the pipe insertion end and the end of the male pipe, the gasket being an elastomeric body having a first portion formed of a relatively low durometer gum to provide a seal against the groove in the male pipe end and having a second portion of a relatively high durometer gum; and a rigid circumferential continuous reinforcing ring fully located within the second portion of the relatively high durometer gum.

2. The pipe joint of claim 1, wherein the first portion of the joint, when viewed in cross-section, includes a narrow entry surface on an interior surface thereof that narrows downward to form a lower compression region. to form a compression seal with the male insertion end when coupling the pipe joint.

The pipe joint of claim 2 wherein the second portion a higher durometry of the joint has an exterior defined by a straight portion, when viewed in cross section, which is inclined in relation to the longitudinal axis of the pipe and which directly contacts the internal pipe groove, the remainder of the outside of the gasket comprises a first portion of lower hardness rubber that occupies the remainder of the annular pipe groove.

The pipe joint of claim 3, wherein the relatively higher durometry rubber portion of the gasket and the rigid reinforcing ring are resistant to deformation so that the body of the gasket as a whole is safely held in the gasket. Slot on the end of the female pipe during the installation of the male end.

The pipe joint of claim 4, wherein the reinforcing ring is formed of metal.

The union of the pipe 5, where the gasket, when viewed from a cross section, has a frontal driving region joined to the lower compression region by means of the region of curved driving surface, the lower compression region attached to the secondary sealing surface by means of the posterior curved surface region terminating at an internal angle of the joint body, "the internal angle connected to the region of an external angle by means of uniform extraction of the surface of the joint. outer joint, the outer concave surface region of the joint joined to the frontal region by a curved concave region.

The pipe joint of claim 6, wherein the secondary sealing surface comprises a first extension of the first relatively lower durometer gum and a second relatively higher durometer gum extension.

The pipe joint of claim 7, wherein the internal angle of the gasket comprises a higher durometer gum in its entirety.

The pipe joint of claim 8, wherein the second portion of the gasket, formed of the relatively higher durometry rubber, is generally rectangular in cross section but terminates at a wedge-shaped point that forms the interior angle of the gasket.

A method of installing a pipe joint into a groove in a female section of a thermoplastic pipe, the method comprising the steps of: installing a seal on a forming mandrel, the gasket located against the stop ring; heating the thermoplastic pipe section and forcing the opening of the pipe section over the previously installed joint to thereby deform an inner surface of heated pipe; separating the pipe section from the stop ring so that the pipe is contracted towards the joint with the deformed inner surface comprising a joint groove in the pipe opening; remove the pipe with the previously installed joint from the mandrel in formation; and wherein the gasket is an elastomeric body having a first portion formed of a relatively low durometry rubber to provide sealing against the stop ring at the female pipe end and having a second portion of a relatively hard durometer gum high, the joint also has a rigid circumferential and continuous reinforcement ring located entirely within the second portion of the relatively high durometer gum.

The method of claim 10, wherein the first portion of the joint, when viewed in cross section, includes a narrow entry surface on an inner surface thereof that narrows downward to form a lower compression region to form a compression seal with the insertion end of the male when coupling the pipe joint.

The method of claim 11, wherein the second portion a higher durometry of the joint has an exterior defined by a straight portion, when viewed in cross section, which is inclined relative to the longitudinal axis of the pipe and directly contacting the inner pipe groove of the outside of the gasket comprising the first portion of lower hardness rubber that occupies the rest of the annular pipe groove.

13. The method of claim 12, wherein the highest durometry rubber portion of the joint and the rigid reinforcing ring are resistant to deformation so that the joint body as a whole is securely held in the groove of the joint. end of female pipe during installation of the male end.

14. The method of claim 13, wherein the reinforcing ring is formed of metal.

15. The method of claim 14 wherein the gasket, when viewed in cross-section, has a front driving region attached to a lower compression region or medium of a curved driving surface region, the lower compression region is joined to the secondary sealing surface by the posterior curved surface region terminating at an inner angle of the joint body, the inner angle is connected to an external angular region by a uniform extraction of outer joint surface, the concave surface region The exterior of the joint is joined to the frontal region by a concave curved region.

16. The method of claim 15, wherein the secondary sealing surface comprises a first extension of a relatively lower first durometer gum and a second relatively higher durometer gum extension.

17. The method of claim 16, wherein the internal angle of the joint completely comprises the highest durometer gum /

18. The method of claim 17, wherein the second portion of the gasket, formed of relatively higher durometry rubber, is generally rectangular in cross section but terminates at a cuneiform point that forms the internal angle of the gasket.

19. The method of claim 18, wherein the exterior of the second portion of the joint, together with the reinforcing ring, provides a reinforced contact point during the steps of forming the pipe groove.