CA1080275A - Pipe coupling - Google Patents
Pipe couplingInfo
- Publication number
- CA1080275A CA1080275A CA283,937A CA283937A CA1080275A CA 1080275 A CA1080275 A CA 1080275A CA 283937 A CA283937 A CA 283937A CA 1080275 A CA1080275 A CA 1080275A
- Authority
- CA
- Canada
- Prior art keywords
- pipe
- face
- sleeve
- ring
- faces
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L25/00—Constructive types of pipe joints not provided for in groups F16L13/00 - F16L23/00 ; Details of pipe joints not otherwise provided for, e.g. electrically conducting or insulating means
- F16L25/06—Constructive types of pipe joints not provided for in groups F16L13/00 - F16L23/00 ; Details of pipe joints not otherwise provided for, e.g. electrically conducting or insulating means comprising radial locking means
- F16L25/08—Constructive types of pipe joints not provided for in groups F16L13/00 - F16L23/00 ; Details of pipe joints not otherwise provided for, e.g. electrically conducting or insulating means comprising radial locking means in the form of screws, nails or the like
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Joints With Pressure Members (AREA)
Abstract
"PIPE COUPLING"
Abstract of the Disclosure A pipe coupling made up of an overall cylindrical metal sleeve having an internal central groove seating a movable centering ring. Pipe ends enter the respective ends of the sleeve and abut the ring. Set screws and spaced-apart tapped holes near the end of the sleeve engage the surfaces of the pipe ends to hold them in the sleeve. The centering ring has special characteristics including tapered sealing faces for engagement with respective pipe ends. The set screws preferably have cup ends to bite into the surfaces of the pipe ends.
Abstract of the Disclosure A pipe coupling made up of an overall cylindrical metal sleeve having an internal central groove seating a movable centering ring. Pipe ends enter the respective ends of the sleeve and abut the ring. Set screws and spaced-apart tapped holes near the end of the sleeve engage the surfaces of the pipe ends to hold them in the sleeve. The centering ring has special characteristics including tapered sealing faces for engagement with respective pipe ends. The set screws preferably have cup ends to bite into the surfaces of the pipe ends.
Description
1080i~5 BACKGROUND OF THE INVENTION
-l. Field of the Invention This invention relates to pipe couplings, and more particularly, to a restraining sleeve-type coupling.
-l. Field of the Invention This invention relates to pipe couplings, and more particularly, to a restraining sleeve-type coupling.
2. Description of the Prior Art Conventional plain ended pipe, whether made from metallic or non-metallic materials are usually joined by mechanical or sleeve-type couplings, or by welding.
Mechanical couplings are normally of the restrain-ing type which means that they seal the joint against leakage and have restraining means as well to hold the pipe together preventing the pipe from separating under the force of inter-nal pressure. This restraining means generally require the pipe to be threaded or grooved at the ends, or to have shoulders fitted to the ends of the pipe to which the couplings are applied. One disadvantage of such mechanical pipe couplings is the extensive end preparation required on the pipe to allow for the use of these couplings on pipe.
Sleeve-type couplings on the other hand usually do not require any end preparation of the pipe to be functional, but they have the disadvantage of not providing any joint restraint for the pipe. External restraint with the sleeve-type coupling must be provided for the pipe, if required.
Sleeve-type couplings may or may not have an integral center-ing ring located midway within the pipe coupling for centering the coupling sleeve correctly over the pipe joint.
Welded joints are common and extensively used for many pipeline applications, but welding has the disadvantage of joint rigidity and of permanence. Removal of an individual pipe from a welded pipeline requires the pipe to be severed physically from the pipeline.
10~1)2'~5 For pipelines conveying solids in a liquid or gaseous medium, there is a problem of providing a coupling between pipe ends which is restraining and, at the same time, prevents turbulence and excessive wear. One attempt to overcome this problem is by use of gasketed flanged joints on the pipe.
Flanged joints are very rigid, however, and this is a disad-vantage for pipelines that require some joint flexibility to relieve stresses in the pipe due to slight movement of the pipeline during its lifetime. Mechanical and sleeve-type couplings, and bell and spigot-type joints, used on pipe for conveying solids, are normally also at a disadvantage because the gap at the joints in the pipeline, which is common for these types of joints, may cause turbulence in the pipeline with the result of obtaining possible excessive wear of the pipe at these joints.
SUMMARY OF THE INVENTION
An aim of the present invention is to overcome the disadvantages discussed and to provide positive advantages in a pipe coupling.
The invention contemplates an overall cylindrical metal sleeve provided inside with a central seating groove for a removable centering ring and at each side a groove for a pressure sealing gasket. The sleeve is provided near its ends with a plurality of spaced-apart tapped holes for set screws.
A preferred centering ring has a solid body of symmetrical cross-section and includes a peripheral seating face, an inside face, and extending between the peripheral face and the inside face a pair of side seating faces extending perpendi-cularly from the peripheral face to a pair of sealing faces continuing inwardly in a bevel angled from the side seating faces toward the inner face. This bevel is effective in caus-ing the abutting pipe end to exert an outward radial force on the centering ring so as to urge the ring more firmly into the internal groove of the pipe coupling. The ring may either be a split ring of metal or a continuous ring made from a plastic or an elastomer preferably have a Shore A Durometer hardness within the range from about 70 to about 80. Preferably the inward angle of the side seating faces to the peripheral face is within the range from about 10 to about 15.
Preferably the set screws are of the type having a cup end which bites into the metal surface of the pipe end.
They are desirably of a non-corrosive alloy, electrochemically compatible with the coupling, so as to avoid setting up a - corrosion circuit.
BRIEF DESCRIPTION OF THE DRAWI~GS
Having thus generally described the invention, it will be referred to in more detail by reference to the accom-panying drawings illustrating a preferred embodiment, and, in which:-Figure 1 is a vertical cross-section, partly in elevation, through a preferred coupling, according to the invention;
Figure 2 is an end elevation of the coupling shown in Figure 1 with the pipe end in cross-section;
Figure 3 is a perspective view of a preferred centering ring forming a part of the ; coupling shown in the previous figures:
Figure 4 is an enlarged fragmentary cross-section, partly in elevation, of the ring shown in Figure 3.
.
.
108l)~S
DESCRIPTION OF T~E PREFERRED EMBODIMENTS
Referring more particularly to the drawings, the preferred pipe coupling sleeve is generally indicated by A, connecting two plain pipe ends s and C.
The sleeve A is a one-piece cylindrical metal body having an inside surface 15, an outside surface 17 and respec-tive end surfaces 19 and 21.
Midway of its length, the body of the sleeve A is provided with an annular rectangular groove having a base surface 18 and respective side surfaces 20 meeting the base surface in slightly rounded corners. A preferred radius for the corners is about 1/32". To each side of the groove D the body is provided with annular grooves 25 and 27 of the cross-section shown, accommodating elastomeric gaskets 29 and 31 respectively of the shape shown, which bear against the groove surfaces and the outside surfaces of the pipe ends B and C and provide a seal between them.
The groove D receives a centering ring E of special construction and shape, against which the pipe ends B and C
bear.
Towards each respective end, the body of the sleeve A is provided with a plurality of equally spaced-apart tapped openings 43 respectively to accommodate set screws F engaging the respective pipe ends B and C.
The ring ~ may be a split ring having a solid body of metal, preferably ductile iron or steel. Or, it may be a continuous non-metallic ring having a solid body of a plastic material as shown, for example, polyurethane, or an elastomer, ; for example, natural or synthetic rubber. The ring E is symmetrical and has a substantially flat peripheral bearing face 50 joined by side bearing faces 52 and 54 perpendicular "
lOl~V;~7~
to the face 50 with rounded corners therebetween. The ring E
has a substantially flat inner face 56 and bevelled side faces 58 and 60 extending between the faces 52, 54 and the face 56 for contact with the pipe ends. Desirably, the bevel of the faces 58 and 60 will be at an angle within the range from about 10 to about 15 from the faces 52 and 54.
Where the ring is of metal it will be of steel or ductile iron and slightly undersize in respect of the groove and split in the radial direction or otherwise to facilitate the distortion needed to get it into the groove. In the event of the ring being of synthetic rubber or plastic material it is continuous. The non-metallic material is selected to be soft enough to allow distortion of the ring for insertion but hard enough to resist its coming out of the groove and to resist undue deformation by the pipe ends. A preferred material would have a Durometer hardness within the range from about 70 to about 80. Examples of suitable materials are polyurethane, styrene butadiene rubber and nitrile rubber, with polyurethane preferred.
In typical ring sizes for 4 to 12 inch diameter couplings, the width from face 52 to face 54 will run to 15/32nds of an inch and faces 52 and 54 will be 3/8th of an inch wide and the total thickness of the ring from the peri-pheral face 50 to the inside face 56 will be from about 3/4 of an inch. For 14 to 2A inch diameter couplings, typical dimensions will be from face 52 to face 54, 23/32nds of an inch, faces 52 and 54 will have a width of 19/32nds, and the thickness from face 50 to face 56 will be about 1 inch.
Preferably special set screws F having a cup point are used for securing the sleeve A to the pipe ends B and C.
The size of the screws may range from about 5/8th of an inch to about 3/4 of an inch. Such a screw has an included angle in the cup point of about 118 + 5, as for example, shown in ANSI Standard B18.6.2 - 1972, published by the American Soceity of Mechanical Engineers, New York, the disclosure of which is hereby incorporated by reference. The set screws are desirably of a non-corrosive alloy, desirably electrochemi-cally compatible to the coupling material so as to avoid setting up a corrosion circuit. Thus, the material of the set screws is heat treated alloy steel, or a hardened carbon steel with the alloy steel preferred for corrosion protection.
Desirably, the alloy steel should meet the AISI (American Iron & Steel Institute) composition requirements for AISI 4137 or AISI 8740 low alloy steel. In completing the joint, the set screws are preferably tightened to a torque within the range from about 60 to about 80 ft/lbs., uniformly applied about the joint.
Generally speaking, couplings of the invention are applicable to pipes having nominal diameters from about 4 inches to about 24 inches. The applicant's coupling is uni-versal in nature, that is to say, it has the capacity to hold pressure and provide strength and restraint, and adequately fill the gap between pipe ends. It has the added advantage that by removing the center ring, the sleeve may be used as an ordinary pipe sleeve. It can also be used as an ordinary coupling (non-restraining) where the pipes are to be re-strained by other means. The coupling also provides the joint flexibility needed for assembling pipe in a pipeline with a long radius curve.
,~, . .
.~
Mechanical couplings are normally of the restrain-ing type which means that they seal the joint against leakage and have restraining means as well to hold the pipe together preventing the pipe from separating under the force of inter-nal pressure. This restraining means generally require the pipe to be threaded or grooved at the ends, or to have shoulders fitted to the ends of the pipe to which the couplings are applied. One disadvantage of such mechanical pipe couplings is the extensive end preparation required on the pipe to allow for the use of these couplings on pipe.
Sleeve-type couplings on the other hand usually do not require any end preparation of the pipe to be functional, but they have the disadvantage of not providing any joint restraint for the pipe. External restraint with the sleeve-type coupling must be provided for the pipe, if required.
Sleeve-type couplings may or may not have an integral center-ing ring located midway within the pipe coupling for centering the coupling sleeve correctly over the pipe joint.
Welded joints are common and extensively used for many pipeline applications, but welding has the disadvantage of joint rigidity and of permanence. Removal of an individual pipe from a welded pipeline requires the pipe to be severed physically from the pipeline.
10~1)2'~5 For pipelines conveying solids in a liquid or gaseous medium, there is a problem of providing a coupling between pipe ends which is restraining and, at the same time, prevents turbulence and excessive wear. One attempt to overcome this problem is by use of gasketed flanged joints on the pipe.
Flanged joints are very rigid, however, and this is a disad-vantage for pipelines that require some joint flexibility to relieve stresses in the pipe due to slight movement of the pipeline during its lifetime. Mechanical and sleeve-type couplings, and bell and spigot-type joints, used on pipe for conveying solids, are normally also at a disadvantage because the gap at the joints in the pipeline, which is common for these types of joints, may cause turbulence in the pipeline with the result of obtaining possible excessive wear of the pipe at these joints.
SUMMARY OF THE INVENTION
An aim of the present invention is to overcome the disadvantages discussed and to provide positive advantages in a pipe coupling.
The invention contemplates an overall cylindrical metal sleeve provided inside with a central seating groove for a removable centering ring and at each side a groove for a pressure sealing gasket. The sleeve is provided near its ends with a plurality of spaced-apart tapped holes for set screws.
A preferred centering ring has a solid body of symmetrical cross-section and includes a peripheral seating face, an inside face, and extending between the peripheral face and the inside face a pair of side seating faces extending perpendi-cularly from the peripheral face to a pair of sealing faces continuing inwardly in a bevel angled from the side seating faces toward the inner face. This bevel is effective in caus-ing the abutting pipe end to exert an outward radial force on the centering ring so as to urge the ring more firmly into the internal groove of the pipe coupling. The ring may either be a split ring of metal or a continuous ring made from a plastic or an elastomer preferably have a Shore A Durometer hardness within the range from about 70 to about 80. Preferably the inward angle of the side seating faces to the peripheral face is within the range from about 10 to about 15.
Preferably the set screws are of the type having a cup end which bites into the metal surface of the pipe end.
They are desirably of a non-corrosive alloy, electrochemically compatible with the coupling, so as to avoid setting up a - corrosion circuit.
BRIEF DESCRIPTION OF THE DRAWI~GS
Having thus generally described the invention, it will be referred to in more detail by reference to the accom-panying drawings illustrating a preferred embodiment, and, in which:-Figure 1 is a vertical cross-section, partly in elevation, through a preferred coupling, according to the invention;
Figure 2 is an end elevation of the coupling shown in Figure 1 with the pipe end in cross-section;
Figure 3 is a perspective view of a preferred centering ring forming a part of the ; coupling shown in the previous figures:
Figure 4 is an enlarged fragmentary cross-section, partly in elevation, of the ring shown in Figure 3.
.
.
108l)~S
DESCRIPTION OF T~E PREFERRED EMBODIMENTS
Referring more particularly to the drawings, the preferred pipe coupling sleeve is generally indicated by A, connecting two plain pipe ends s and C.
The sleeve A is a one-piece cylindrical metal body having an inside surface 15, an outside surface 17 and respec-tive end surfaces 19 and 21.
Midway of its length, the body of the sleeve A is provided with an annular rectangular groove having a base surface 18 and respective side surfaces 20 meeting the base surface in slightly rounded corners. A preferred radius for the corners is about 1/32". To each side of the groove D the body is provided with annular grooves 25 and 27 of the cross-section shown, accommodating elastomeric gaskets 29 and 31 respectively of the shape shown, which bear against the groove surfaces and the outside surfaces of the pipe ends B and C and provide a seal between them.
The groove D receives a centering ring E of special construction and shape, against which the pipe ends B and C
bear.
Towards each respective end, the body of the sleeve A is provided with a plurality of equally spaced-apart tapped openings 43 respectively to accommodate set screws F engaging the respective pipe ends B and C.
The ring ~ may be a split ring having a solid body of metal, preferably ductile iron or steel. Or, it may be a continuous non-metallic ring having a solid body of a plastic material as shown, for example, polyurethane, or an elastomer, ; for example, natural or synthetic rubber. The ring E is symmetrical and has a substantially flat peripheral bearing face 50 joined by side bearing faces 52 and 54 perpendicular "
lOl~V;~7~
to the face 50 with rounded corners therebetween. The ring E
has a substantially flat inner face 56 and bevelled side faces 58 and 60 extending between the faces 52, 54 and the face 56 for contact with the pipe ends. Desirably, the bevel of the faces 58 and 60 will be at an angle within the range from about 10 to about 15 from the faces 52 and 54.
Where the ring is of metal it will be of steel or ductile iron and slightly undersize in respect of the groove and split in the radial direction or otherwise to facilitate the distortion needed to get it into the groove. In the event of the ring being of synthetic rubber or plastic material it is continuous. The non-metallic material is selected to be soft enough to allow distortion of the ring for insertion but hard enough to resist its coming out of the groove and to resist undue deformation by the pipe ends. A preferred material would have a Durometer hardness within the range from about 70 to about 80. Examples of suitable materials are polyurethane, styrene butadiene rubber and nitrile rubber, with polyurethane preferred.
In typical ring sizes for 4 to 12 inch diameter couplings, the width from face 52 to face 54 will run to 15/32nds of an inch and faces 52 and 54 will be 3/8th of an inch wide and the total thickness of the ring from the peri-pheral face 50 to the inside face 56 will be from about 3/4 of an inch. For 14 to 2A inch diameter couplings, typical dimensions will be from face 52 to face 54, 23/32nds of an inch, faces 52 and 54 will have a width of 19/32nds, and the thickness from face 50 to face 56 will be about 1 inch.
Preferably special set screws F having a cup point are used for securing the sleeve A to the pipe ends B and C.
The size of the screws may range from about 5/8th of an inch to about 3/4 of an inch. Such a screw has an included angle in the cup point of about 118 + 5, as for example, shown in ANSI Standard B18.6.2 - 1972, published by the American Soceity of Mechanical Engineers, New York, the disclosure of which is hereby incorporated by reference. The set screws are desirably of a non-corrosive alloy, desirably electrochemi-cally compatible to the coupling material so as to avoid setting up a corrosion circuit. Thus, the material of the set screws is heat treated alloy steel, or a hardened carbon steel with the alloy steel preferred for corrosion protection.
Desirably, the alloy steel should meet the AISI (American Iron & Steel Institute) composition requirements for AISI 4137 or AISI 8740 low alloy steel. In completing the joint, the set screws are preferably tightened to a torque within the range from about 60 to about 80 ft/lbs., uniformly applied about the joint.
Generally speaking, couplings of the invention are applicable to pipes having nominal diameters from about 4 inches to about 24 inches. The applicant's coupling is uni-versal in nature, that is to say, it has the capacity to hold pressure and provide strength and restraint, and adequately fill the gap between pipe ends. It has the added advantage that by removing the center ring, the sleeve may be used as an ordinary pipe sleeve. It can also be used as an ordinary coupling (non-restraining) where the pipes are to be re-strained by other means. The coupling also provides the joint flexibility needed for assembling pipe in a pipeline with a long radius curve.
,~, . .
.~
Claims (11)
1. A restraining pipe joint, comprising, an overall cylindrical metal sleeve having opposite open ends, an outer face and an inner face presenting a double socket of uniform inside diameter and provided with an internal rectangular seating groove located centrally and extending from the inner face and presenting peripheral and side bearing faces and a pair of packing grooves extending from the inner face spaced from each side of the central groove, a separate collapsible centering ring of substantially compression-resistant material removably sprung into seated position in said central groove and protruding therefrom beyond the inner face, said centering ring having a one-piece symmetrical body of polygonal cross-section provided with a part tightly fitting the groove and including a peripheral bearing face and parallel side bearing faces engaging the faces of the groove, and an inside wedge part having opposite side smooth contact faces extending at an inward angle from the side seating faces to an inner cylindrical face of uniform inside diameter concentric to the peripheral face, a cylindrical pipe end entering each open end of the sleeve presenting a cylindrical outside surface of overall uniform diameter slightly less than that of the inside diameter of said socket and having a smooth annular inwardly tapered rim abutting a contact face of the centering ring about the entire circumference of the ring thereby to exert a radial force on the ring and maintaining the pipe ends in coaxial alignment, each pipe end having a uniform inside diameter substantially the same as that of the centering ring whereby the inner surface presented by the pipe ends and ring are substantially continuous, a pressure sealing gasket in each of the packing grooves bearing against a respective pipe end, and restraining means in which each end of the sleeve is provided with a plurality of spaced-apart tapped holes there-through near its end, and set screws in said holes tightened against the surface of the respective pipe ends locking them into the sleeve and retaining them in coaxial alignment in abutting relationship to the centering ring.
2. A pipe joint, as defined in claim 1, in which the set screws have cup points biting into the metal of the pipe ends.
3. A pipe joint, as defined in claim 1, in which the inward angle is within the range from about 10° to about 15°.
4. A pipe joint, as defined in claim 1, in which the centering ring is a continuous ring made from a plastic or elastomer having a Durometer hardness within the range from about 70 to about 80.
5. A pipe joint, as defined in claim 1, in which the ring is a split ring made from metal.
6. A coupling element for pipe joints, comprising, an overall cylindrical metal sleeve having an outer face of constant outside diameter and a smooth inner face pre-senting a double socket of uniform inside diameter and being pro-vided with an internal seating groove rectangular in cross-section located centrally and extending from the inner face and an internal groove spaced from each side of the central groove extending from the inner face for receiving a pressure sealing gasket, a separate solid collapsible centering ring of substant-ially compression-resistant material removably sprung into seated position in said central groove and protruding therefrom beyond the inner face, said centering ring having a one-piece symmet-rical solid body of polygonal cross-section provided with a part tightly fitting the groove and including a peripheral bearing face and parallel side bearing faces engaging the faces of the groove, and an inside wedge part having opposite smooth contact faces extending at an inward angle from the side seating faces to an inner smooth cylindrical face of uniform inside diameter, for contact with the pipe ends of the same inside diameter, the sleeve being provided with opposite open ends, each for receiving a pipe end of slightly less outside diameter than the outside diameter of the sleeve and having an inner surface of substantially the same inside diameter as that of the centering ring, said sleeve having a plurality of spaced-apart tapped holes near its ends for receiving set screws to engage pipe ends inserted in the sleeve.
7. A coupling element, as defined in claim 6, in which the tapped holes contain set screws.
8. A coupling element, as defined in claim 7, in which the set screws have cup points biting into the metal of the pipe ends.
9. A centering ring for coupling pipe ends, comprising, a symmetrical collapsible one-piece body of substant-ially non-compressible material and of polygonal cross-section provided with a part for fitting the annular rectangular groove of a retaining sleeve and including a peripheral bearing face and parallel side bearing faces perpendicular thereto for engaging faces of the groove, and an inside wedge part having opposed side smooth contact faces for abutting the rims of pipe ends extending at an inward angle from the side seating faces to an inner cylind-rical face of uniform inside diameter concentric to the peri-pheral face for registering with the inside surfaces of pipe ends of the same inside diameter.
10. A centering ring, as defined in claim 9, wherein the body is continuous and made from a plastic or elastomer having a Durometer hardness within the range from about 70 to about 80.
11. A ring, as defined in claim 9, in which the body is made from metal and split.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA283,937A CA1080275A (en) | 1977-08-02 | 1977-08-02 | Pipe coupling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA283,937A CA1080275A (en) | 1977-08-02 | 1977-08-02 | Pipe coupling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1080275A true CA1080275A (en) | 1980-06-24 |
Family
ID=4109262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,937A Expired CA1080275A (en) | 1977-08-02 | 1977-08-02 | Pipe coupling |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1080275A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000009932A1 (en) * | 1998-08-14 | 2000-02-24 | Do Yean Lee | Pipe coupler |
| CN112049992A (en) * | 2020-09-08 | 2020-12-08 | 江苏青阳管业有限公司 | Stainless steel lined composite pipe sealing head |
| CN112664742A (en) * | 2020-12-21 | 2021-04-16 | 王虹 | Straight pipe pressure balance type compensator |
-
1977
- 1977-08-02 CA CA283,937A patent/CA1080275A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000009932A1 (en) * | 1998-08-14 | 2000-02-24 | Do Yean Lee | Pipe coupler |
| CN112049992A (en) * | 2020-09-08 | 2020-12-08 | 江苏青阳管业有限公司 | Stainless steel lined composite pipe sealing head |
| CN112664742A (en) * | 2020-12-21 | 2021-04-16 | 王虹 | Straight pipe pressure balance type compensator |
| CN112664742B (en) * | 2020-12-21 | 2022-11-18 | 河北瑞星燃气设备股份有限公司 | Straight pipe pressure balance type compensator |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |