MXPA02008374A

MXPA02008374A - Fire safe closure ring seal system for plug valves.

Info

Publication number: MXPA02008374A
Application number: MXPA02008374A
Authority: MX
Inventors: Gordon M Smith
Original assignee: Gen Valve Inc
Priority date: 2000-02-28
Filing date: 2001-02-23
Publication date: 2002-12-13
Also published as: WO2001065156A3; BR0108934A; WO2001065156A2; CA2401154A1; JP2003525411A

Abstract

A seal system comprises a non flat cross section, fire resistant compressible ring and an annular pocket formed between two engagting surfaces of a pressure vessel such as a plug valve. The pocket is formed by providing a chamfer in one such surface which is then enclosed by the other such surface. The ring is compressed within the pocket to substantially fill the pocket upon mating of the two surfaces.

Description

SEALING SYSTEM WITH FIRE PROOF CLOSING RING FOR SHUTTER VALVES FIELD OF THE INVENTION The present invention relates generally to shut-off valves and more particularly to a sealing ring closure system which replaces conventional packaging and allows smaller locks, smaller caps and increased effectiveness and dependence.

ANTECEDENTS OF THE TECHNIQUE The current state of the art with regard to fire safety for sealing valves consists of graphite and ring packings. The prior art consists of asbestos and graphite materials that are sufficiently elastic in response to compressive loads to effect a seal that is strong enough to withstand pressure and mechanical loads. These materials are also sufficient to withstand fire temperatures greater than 760 ° C. They are also resistant to most chemicals. Conventional seals for sealing valves tend to be flat and wide. For example, in a typical embodiment of sealing valves of the prior art, a circular package has a thickness of 0.0762 cm. and a width of 0.952 to 1.905 cm. The package is deployed outwardly from the ID bore of the valve body to the inner side of the body locking bolts, thus requiring the body to have a circular, smooth and flat area for installation. The body closure bolts are required to maintain the integrity of the pressure vessel despite the hydrostatic loads, the valve operator impulse and the packing seal load that is not insubstantial. It will be very advantageous if the flat graphite gasket of the prior art could be replaced by a seal that would be more effective and would require lower degrees of closure load.

BRIEF DESCRIPTION OF THE INVENTION The fire seal of the present invention replaces the prior art gasket with a fireproof compact ring seal. The seal of the present invention differs from the packaging of the prior art in two main ways. First, the seal has a different form. Unlike the packaging of the prior art, the inventive seal is not flat. It is preferably round, square, triangular, trapezoidal or with another non-planar cross-section for sealing with a lower closing load. Secondly, the seal is located in a more bevelled outer region of the body flange which is trapped against the adjacent closure flange. As it is thicker, the seal is more elastic. The Elasticity combined with the beveled configuration, produces a significant sealing effectiveness without the same degree of closing load. The lower closing load allows the use of smaller components. The body tab can be smaller and the closing tab can be thinner. The result is a lighter valve structure with a lower cost. In addition, the bolts can be smaller which also reduces the weight and costs OBJECTIVES OF THE INVENTION Therefore, it is a primary object of the present invention to provide a fire-proof ring sealing system for shut-off valves, and which results in lighter and more economical structures. Another object of the invention is to provide an improved seal valve having a fireproof non-flat ring seal and a gap installation for beveled seal to reduce the closing load. A further object of the invention is to reduce the flange of the body, the closing flange and the size of the bolts and the weight in the shutter-type valve, providing a more effective seal against fire and locating the seal in a more effective place. in the valve.

Another object of the invention is to provide an improved sealing system with fireproof ring for vessels that are designed to contain fluids under pressure.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned objects and advantages of the present invention, as well as the objects and additional advantages thereof, will be more fully understood below as a result of the detailed description of a preferred embodiment taken together with the following drawings in which: Figure 1 is a cross-sectional view of a shut-off valve implemented with a fire-proof ring sealing system according to a preferred embodiment of the invention; Figure 2 is an enlarged view of the portion of the obturator valve that in Figure 1 has the indication "see Figure 2" with a bolt omitted for a visual advantage; Figure 3 is a three-dimensional view of a ring seal that is used in the preferred embodiment of Figure 1; Figure 4 is an elevated view of the ring seal of Figure 3; Figure 5 is a side view of the ring seal; Figure 6 is an enlarged view of the portion of the ring seal which in Figure 5 has the indication "see Figure 6".

DETAILED DESCRIPTION OF A PREFERRED MODALITY Now, referring to the accompanying figures and Figures 1 and 2 in particular, it will be seen that the shut-off valve 10 comprises a body 12 housing a rotating plug 14 having a flow passage 16. The valve is shown in the configuration open with the flow passage 16 aligned with connection tubes (not shown) secured to the valve 10 with connecting flanges 18. The plug 14 has a pair of chocks 15 fixed on opposite sides of the plug to stop the flow when the plug is turned at 90 degrees to place the flow passage 16 in a direction perpendicular to that shown in Fig. 1. The plug is integral to a upper stump 20 and a lower stump 26. The upper stump 20 is controlled by an operator 22 and a handle 24 for placing plug 14 in the open or closed position. This form of sealing valve is called a double blockage and purge valve because it allows the fluid in the valve body to be purged when the chocks are seated against the inlet and outlet ports. However, it should be understood that the fire-proof ring sealing system described herein is not limited to such valves, and that it can be advantageously used in any valve, pump or other structure in which a seal is preferred. Fireproof of a closed and pressurized fluid. A bottom cover 28 is secured to the lower end of the body 12 by means of bolts 29. The The upper end of the body 12 is housed by a cap 30 which is secured by a locking ring 32 and bolts 34. The cap 30 has a flange 36 which is in contact with the upper surface 38 of the body 12. As can be seen better in Figure 2, the upper surface 38 has a bevel 40 to form an annular recess 42 which receives the fireproof ring seal 44 of the present invention. Below the bezel 40 is an O46 ring that is mounted on the main portion of the cap 30. As best seen in Figures 3 to 6, the fire ring seal 44 is circular and has a trapezoidal cross section with a axial end of the circular seal being thicker than the other axial end. The thicker axial end is placed on the upper edge of the bevel 40 and, as can be seen in Figure 2, is in direct compression contact with the flange 36 of the cap 30. The fire-ring seal 44 is preferably a GRAFOIL® ring that is available with the Union Carbide Company of New York City. Due to the unique bevel configuration for placing the ring seal 44, the seal is more elastic and is subject to both lateral and longitudinal compression to effect the fireproof seal. The shape and dimensions of the ring seal 44 in relation to the shape and dimensions of the recess 42 allow effective sealing with a lower closing load of the bolts 34. More particularly, the axial length of the ring seal 44 (A + B in FIG 6) is preferably greater than the depth of the bevel 40 along the axial direction of the plug 14 by the length B (of FIG 6) and the thickness C of the ring seal 44 is preferably equal to the width of the bevel 40 along the radial direction of the plug 14. These relative dimensions of the ring seal 44 and the recess 42, ensure that the ring seal fills the beveled gap before the connection of the cap 30 to the body 12. In addition, it ensures an excellent seal by tightening the bolts 34 with a much lower load level than that required with the flat packing seal of the prior art. This allows the use of smaller bolts. In addition, the lower closing load requirements also allow a reduction in the size of the body surface 38, a reduction in the size of the flange of the cap 36 and thus, a lighter and more economical sealing valve but which continues to comply with all regulatory specifications against fire. Having thus described a preferred embodiment of the invention, having understood that many alternative shapes, sizes and locations are contemplated for the ring seal and the beveled chamber, what is claimed is:

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A sealing valve (10) having a body (12) containing a rotating cap (14), the cap has a passage (16) for selective alignment with inlet and outlet connection tubes, the body is covered by a cap (30) and a bottom cover (28) to form a chamber inside said body, said cap has a flange (36) which engages an upper surface (38) of said body and which has a seal against fire ( 44) between them, wherein said seal comprises a compressible and non-planar heat resistant ring, said ring is located in a beveled region (40) of said upper surface of the body, said beveled region forms an annular recess (42) that is configured to receive said ring.

2. The sealing valve according to claim 1, further characterized in that the ring has a trapezoidal cross section.

3. The sealing valve according to claim 1 or 2, further characterized in that said ring has a non-compressed length that exceeds the depth of said gap.

4. The sealing valve according to claim 1, 2 or 3, further characterized in that said ring has a size and a cross section for compressibly filling said annular gap with the union of the cap to the body.

5. The sealing valve according to any of the preceding claims, further characterized in that said ring has a size and a shape for applying sealing forces in two orthogonal directions with the union of said cap to said body.

6. - A fire sealing apparatus for use in a closed container containing a fluid under pressure, the container has at least two contact surfaces that overlap at least partially in a joint to define an annular recess (42) formed by a bevel (40) on one of the joining surfaces, said fire sealing apparatus comprises a heat-resistant compressible ring (44) wherein said ring has a non-planar cross-section and is positioned within said annular gap ( 42), the arrangement is such that the other of said joining surfaces compresses said ring into the gap.

7. The fire sealing apparatus according to claim 6, further characterized in that said ring has a trapezoidal cross section.

8. The fire sealing apparatus according to claim 6 or 7, further characterized in that said ring has a non-compressed length that exceeds the depth of said gap.

9. The fire sealing apparatus according to any of claims 6, 7 or 8, further characterized in that said ring has a size and a cross section to compressively fill said annular gap at the junction of said cap with said body.

10. The fire sealing apparatus according to any of claims 6 to 9, further characterized in that said ring has a size and a shape for applying sealing forces in two orthogonal directions with the union of said cap to said body.