GASKET RING AND FLANGE CONNECTION USING SUCH GASKET RING

Abstract

In a gasket ring for sealing flange connections and flange connections including the gasket ring, preferably connections of flanges made of plastic, in the radial direction the gasket ring is subdivided into a primary gasket ring and a secondary gasket ring, both rings being concentrically arranged and connected to each other, the secondary gasket ring being arranged on the radial outside of the primary gasket ring, the modulus of elasticity of material of the secondary gasket ring being at least 10 times higher than the modulus of elasticity of the material of the primary gasket ring, the secondary gasket ring in the major part of its radial extension having an axial main height smaller than the maximum axial height of the primary gasket ring.

Claims

1. Gasket ring for sealing flange connections, comprising a primary gasket ring and a secondary gasket ring, the primary and secondary gasket rings being concentrically arranged and connected to each other, the secondary gasket ring being arranged on the radial outside of the primary gasket ring, a modulus of elasticity of a material of the secondary gasket ring being at least 10 times higher than a modulus of elasticity of a material of the primary gasket ring, the secondary gasket ring in a major part of its radial extent having an axial main height smaller than a maximum axial height of the primary gasket ring.

2. The gasket ring according to claim 1, wherein the secondary gasket ring comprises a respective at least one axial protrusion on each axial side thereof, an axial height of the secondary gasket ring between axial ends of each of the at least one axial protrusion on each axial side being bigger than the axial main height and smaller than or equal to the maximum axial height of the primary gasket ring.

3. The gasket ring according to claim 2, wherein each of the at least one axial protrusion has a uniform axial height or is symmetrically tapered in an axial direction to form a pointed tip or has an end which is curved in an axial cross-section.

4. The gasket ring according to claim 1, wherein the secondary gasket ring comprises a respective at least one axial recess on each axial side thereof, an axial height of the secondary gasket ring between axial ends of each of the at least one axial recess on each axial side being smaller than the main height.

5. The gasket ring according to claim 4, wherein each of the at least one axial recess is tapered towards its bottom.

6. The gasket ring according to claim 1, wherein the secondary gasket ring in a major part of its radial extent has a uniform axial main height.

7. The gasket ring according to claim 1, wherein the primary gasket ring has a uniform axial height.

8. The gasket ring according to claim 1, wherein the primary gasket ring and the secondary gasket ring are connected by fusing or gluing or injection moulding and/or a form-closed link.

9. The gasket ring according to claim 1, wherein the primary gasket ring is made of a rubber material.

10. The gasket ring according to claim 1, wherein the secondary gasket ring is made of polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) or fiber-reinforced plastic (FRP).

11. The flange connection comprising two flanges and the gasket ring according to claim 1 interposed between and in contact with the two flanges.

12. The flange connection of claim 11, wherein the secondary gasket ring are made of a same plastic.

13. The gasket ring according to claim 2, wherein the at least one axial protrusion on a first axial side of the secondary gasket ring has a same position as the at least one axial protrusion on a second axial side of the secondary gasket ring.

14. The gasket ring according to claim 3, wherein the curved end of the at least one axial protrusion is semicircular in the axial cross-section.

15. The gasket ring according to claim 13, wherein the secondary gasket ring comprises a respective at least one axial protrusion on each axial side thereof, an axial height of the secondary gasket ring between axial ends of the at least one axial protrusion on each axial side being bigger than the axial main height and smaller than or equal to the maximum axial height of the primary gasket ring.

16. The gasket ring according to claim 15, wherein the curved end of the at least one axial protrusion is semicircular in the axial cross-section.

17. The gasket ring according to claim 8, wherein the form-closed link comprises a recess in the secondary gasket ring filled by material forming the primary gasket ring

18. The gasket ring according to claim 4, wherein the at least one axial recess on a first axial side of the secondary gasket ring has a same position as the at least one axial recess on a second axial side of the secondary gasket ring.

19. The gasket ring according to claim 5, wherein the bottom of each of the at least one axial recess is semicircular in an axial cross-section of the axial recess.

20. The gasket ring according to claim 9, wherein the rubber material is acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM), fluoro-natural rubber (FKM or FPM), or perfluoro-natural rubber (FFKM or FFPM).

21. The flange connection according to claim 11, wherein the two flanges are made of plastic.

Description

PREFERRED EMBODIMENTS ARE SHOWN IN THE DRAWINGS

[0021] FIG. 1 shows with respect to a middle axis 1 of the gasket ring on the left side the non-compressed gasket ring and on the right side the compressed gasket ring of the invention.

[0022] It can clearly be seen that the gasket ring is subdivided into two connected rings, the primary gasket ring 2 and the secondary gasket ring 3. The primary gasket ring 2 has a uniform axial height along its entire radial extent. The axial extent is along the axis 1, whereas the radial extent is perpendicular to axis 1.

[0023] The secondary gasket ring 3 also has a uniform height along the major part 3a of its entire radial extent, preferably along more than 50%, more preferred more than 60% of its entire radial extent. Since this height is given in the major part, the height is also named main height. This height is not necessarily uniform in all possible embodiments, but in the shown one.

[0024] The main height is less than the maximum height of the primary gasket ring, which is uniform in the shown case.

[0025] This means that by tightening the flanges the primary gasket ring 2 will provide the primary seal. Furthermore, the compression of the primary gasket ring 2 will be restricted upon contact of the flanges with the secondary gasket ring 3 in its major part 3a.

[0026] It can also be seen that the secondary gasket ring 3 has respective protrusions 3b on either axial side of the gasket ring, the protrusions 3b being on the same radial position and having a height bigger than the main height. The protrusions are positioned outside, preferably adjacent the major part having the named main height. Furthermore, on the radial outside of the protrusion respective recesses 3c are formed on either axial side on the same radial positions having an axial height being smaller than the main height.

[0027] On the right side of FIG. 1 the compressed state is shown, proving that the compression of the primary gasket ring is restricted essentially to the axial height of the secondary gasket ring in its major part 3a. Furthermore, the protrusions are completely pressed flat.

[0028] This leads to a pressure diagram shown below the gasket ring construction. It can be seen that the pressure is higher at the position of the secondary gasket ring and is highest at the position of the protrusion. Accordingly, the secondary gasket ring is positioned in the main load connection of the flanges and the primary gasket in the force shunt connection of the flanges.

[0029] In this embodiment the primary gasket ring may be made of rubber having a modulus of elasticity of 5 MPa, whereas the secondary gasket ring may be made of Polyethylene, having a modulus of elasticity of 70 MPa, being more than 10 times higher.

[0030] The connection between the two gasket rings may be established by gluing.

[0031] FIG. 2 shows another embodiment in which the secondary gasket rings does have a tip shaped protrusion that tapers linearly in axial direction to a point. There is no recess in the secondary gasket ring. In addition, here the pressure diagram proves the primary gasket ring to be positioned in the force shunt connection of the flanges. This maintains a long term stability of the primary gasket ring.

[0032] FIG. 3 shows another different embodiment of the shape of the protrusion, that is provided with a constant height along it entire radial extension.

[0033] FIGS. 4 and 5 show a form closed link 4 between the primary and secondary gasket ring. For example, material of the primary gasket ring 2 may be injected into a recess in the radial side face of the secondary gasket ring 3 in an injection moulding process in which the already existing secondary gasket ring 3 is positioned in the mould prior to the injection of the material that forms the primary gasket ring 2.