JPH0348085A - Fireproof gate valve - Google Patents

Abstract

PURPOSE: To obtain a gate valve which can endure operation pressure while being subjected to fire or after that by combining a fusible element surrounding a support sleeve attached to a valve spindle and a circular back surface valve seat element. CONSTITUTION: A fusible ring assembly 46 supports a valve spindle 30 between bearing assemblies 42 and 44 under normal operation temperature. The assembly 46 is composed of an axially divided sleeve 48, a holding ring 50 and a fusible ring 52. When a valve 10 is subjected to fire and the fusible ring 52 is melted, a sealing surface of a valve spindle flange 56 is pressed a valve spindle 30 upward until it is abutted against a bonnet valve seat surface 62, for preventing fluid leakage from a bonnet port 58. In such a case, the holding ring 50 loosely surrounds the sleeve 48 and the fusible ring 52. The molten material of the fusible ring 52 is flowed out from a transverse hole 54. It is thus possible to obtain a fluid control valve for super high temperature, particularly a gate valve which can sufficiently endure operation pressure while being subjected to fire or after that.

Description

BACKGROUND OF THE INVENTION The present invention relates to fluid control valves for very high temperatures, particularly gate valves that withstand operating pressures well during or after exposure to fire.

As indicated in patent specifications and other literature, the industry, particularly the oil and gas industry, has developed a system for stem-actuated valves that withstand the destructive effects of fire and other high temperatures without losing safe, fluid-tight control of high-pressure systems. Many efforts have been made in recent years to provide services to industries involved in production. The result of this effort is to include metal-to-metal seals, valves, rod back-seating elements, and fusible elements to prevent back-seating during normal operating temperatures and to provide back-seating when temperatures increase. A variety of valves began to be manufactured. However effective these designs are, each has one or more drawbacks that may leave users unsatisfied.

SUMMARY OF THE INVENTION Contemplated to overcome the shortcomings of known fire-resistant stem-operated valves, the present invention provides improvements in the location of fusible elements and their functional relationship to the stem, stem bearing, and bonnet, It provides an improved design of the back valve seat as well as an improved metal-to-metal sealing scheme between the valve closing element and the valve body.

As incorporated in a non-rising stem type gate valve, an annular back surface having an improved fusible element surrounding a support sleeve attached to the valve stem and an annular sealing surface, preferably of circular cross-section, on the valve stem. The present invention includes valve seat elements alone or in any combination.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG.
), a valve chamber (16) intersecting the fluid passageway (14), and a plurality of circumferentially spaced studs (20) and nuts (22)
2) Valve bonnet (18) removably attached to
, a bonnet cap (24) attached to the bonnet (+81) by a threaded portion (26), and a passageway (14).
a valve stem (28) disposed within the valve chamber (16) to control flow through the valve stem (28) and a valve stem (28) extending from the partition plate (28) through the bonnet (18) and cap (24);
30) and a handle (
32) and other suitable equipment. Valve stem (30
) is rotated, openings are provided in the partition plate (28) such that the valve partition plate (28) moves between a closed position (as shown) and an open position within the valve chamber (16) of the valve body (12). A valve stem (30) is screwed into a lifting pin (34) (FIGS. 1, 5, 6) which is inserted into a lateral bore (36). Although the valve chamber (16) is shown as a circular cavity in the preferred embodiment, the cavity may also be rectangular, square, etc. in cross-section. The valve chamber (16) is used to properly align the valve partition plate (28). The valve partition plate (28) is made into a circular, rectangular, square, etc. shape to fit the valve chamber (16).

An annular packing (18) near the top of the bonnet (18) provides a fluid seal between the bonnet (18) and the valve stem (30).
38), and a gland-type gasket holding bolt (40) screwed into the bonnet functions as a gasket retainer. 1 so that the valve stem (30) can easily rotate to open and close the valve above the packing bolt (40).
A pair of thrust bearing assemblies (42, 44) surround the valve stem (30). A fusible ring assembly (46) axially supports the valve stem (30) in the position shown during normal operating temperatures.
1 and 2) between the bearing assemblies (42, 44). The assembly (46) includes an axially split sleeve (48) having an annular radial flange (48I) extending outwardly from the lower end and a retaining ring having an annular radial flange (5h) extending inwardly from the upper end. (50) and a fusible ring (52) sandwiched between the flanges (481, 50al). The retaining ring (50) is formed by two identical semi-circular segments (only one shown) inserted between opposing annular shoulders (30c, 30b) around the retaining ring (50). Sleeve (48
) and fusible ring (52), and after being melted by fire or other sufficiently high temperature, ring (52)
one or more lateral holes (54
).

As best seen in Figure 3, an annular back valve seat flange (56) extends radially outwardly from the valve stem (30) below the bonnet (18) and above the valve stem threads (3h). It has an upwardly facing annular metal sealing surface (56g) with a round cross section.

The lower part of the bonnet hole opening (58) has an annular radial surface (62) acting as a valve seat for the sealing surface (56a) at point (60).
A counterbore is provided to give O-rings (64, 66) are attached to the rear valve seat flange (18) to act as a sealing element between the flange and the bonnet (18) at high temperatures.
56).

If the fusible ring (52) melts due to the valve (lO) being exposed to fire or other sufficiently high temperatures, the valve stem flange (56)
) The fluid pressure within the valve body pushes the valve stem (30) upward until the sealing surface (561) of the bonnet valve seat surface (62) contacts the bonnet valve seat surface (62), functionalizing the metal-to-metal valve seat against the back surface of the bonnet valve stem and closing the bonnet. Preventing fluid from leaking through the aperture (58).

When this occurs, the split sleeve (48) is moved upwardly with the valve stem (30).

In order to achieve reliable rear seating of the valve stem even under relatively low valve internal pressure, the nut and bearing assembly (42) are located in the counterbore hole (40a) in the upper part of the packing retainer (411). ) compressed between the helical springs (68
) (better seen in Figure 2) is provided to move the bearing assembly and therefore the split sleeve (48) and valve stem (30) upwardly when the fusible ring (52) melts.

As shown in FIGS. 1 and 4, a valve seat includes a uniquely shaped sleeve-like metal valve seat element (70) residing within a counterbore (72) of a fluid passageway (14) in the body. The downstream side (28a) of the valve partition plate (28) is fluid-tightly sealed to the valve body (12).

The valve seat element (70) includes an annular sealing lip (74) with a sealing surface (74a) of circular cross-section. Before installation, the outer diameter of the sealing surface (74a) is slightly larger than the inner diameter of the counterbore (72), so that the sealing surface is pressed against the counterbore when the element (70) is installed in the functional position. is adapted to provide a metal-to-metal seal between element (70) and valve body (12). 0 falling into the outer groove (78) of element (70)
The ring (76) is connected to the fluid passageway (1) at normal operating temperatures.
4) through between the element (70) and the counterbore and the lip (
74) Prevent pressure from leaking towards.

A fluid passage (1) is provided on the upstream side (28b) of the partition plate (28).
Another sleeve-like valve seat element (80) (FIG. 1) located in the counterbore (82) of 4) is biased toward the partition plate by one or more disc springs (84). , this axial load also causes an initial seal between the downstream side (28a) of the partition plate (28) and the upstream end (70a) of the element (70).

FIG. 7 Another form of downstream valve seat element is shown in FIG. 7 as (90). The sleeve-like element (90) has an annular sealing surface (92) of circular cross-section on its downstream radial end face (94). This sealing surface (92) is connected to the counterbore hole (72) in the valve body.
) abutting and cooperating with opposing radial surfaces (96) of the valve body (12) to provide a fluid-tight metal-to-metal seal between the valve body (12) and the element (90). Additional sealing capability at normal temperatures and low pressures can be provided by placing an O-ring (98) in the circumferential groove (+00) on the outer surface of the element (90).

FIG. 8 Another design for the back valve seat of the valve stem is shown in FIG. This design includes a frusto-conical thickened section (110) above the threaded portion (30a) of the valve stem and a sloping inlet (+12) in the complementary shape of the bonnet borehole (58). The inclined inlet (+12) is connected to the frustoconical valve stem portion (lI
I]l, and the fusible ring (52
) melts, the valve stem (30) rises until the valve stem portion (Ill) abuts the angled inlet, providing a fluid-tight metal-to-metal seal between the valve stem and the bonnet.

FIG. 9 is an alternative embodiment of the fusible ring assembly (46). In this embodiment, the retaining ring (50) in FIGS. 1 and 2 is absent, and the fusible ring (52) is in direct contact with the upper bearing assembly (44).

FIG. 10 Another variant embodiment of the fusible ring assembly is shown in FIG. 10, in which the lower bearing assembly (+4
21 has a significantly larger outer diameter than the corresponding part (42) (FIGS. 1 and 2) and abuts the lower end of the retaining ring (50). Therefore, in FIG. 10, the fusible ring (
52) does not provide a supporting function to any of the bearing assemblies (142, 44), and this fusible ring (52)
When the valve stem (30) and split sleeve (48
) rises until the valve stem rear valve seat contacts the bonnet, while the lower lower bearing assembly (1421) remains in the position shown.

Although the best mode for carrying out the invention has been disclosed and described herein, it will be obvious that modifications and changes may be made thereto without departing from the essential subject matter of the invention.

[Brief explanation of drawings]

FIG. 1 is a center vertical cross-sectional view, with several parts fully shown, of a fire-resistant gate valve embodying features of the invention; FIG. 2 is an enlarged view of the valve stem bearing area at the top of FIG. 1; , Figure 3 is an enlarged view of the valve seat area on the back of the valve stem in the center of Figure 1, Figure 4
The figure is an enlarged view of the gate valve seat area at the bottom of Figure 1.
The figure is along line 5-5 in Figure 1, and Figure 6 is along line 6-5 in Figure 1.
Figure 7 is a reduced view similar to Figure 4, showing another type of gate valve seat having an annular metal sealing surface with a circular cross-section; Figure 8 is a view taken along line 6; FIG. 9 is a reduced view similar to FIG. 3 showing another embodiment of the fusible ring assembly according to the invention; FIG. 10 is a reduced view similar to FIG. FIG. 2 is a center vertical cross-sectional view showing yet another embodiment of a fusible ring assembly according to the present invention. patent application agent

Claims (17)

[Claims] (1) a body having a fluid passageway therethrough and a chamber intersecting the fluid passageway; a valve-closing element disposed within the chamber for controlling fluid through the fluid passage; and a valve-closing element attached to the body and having a chamber intersecting the fluid passageway; a valve stem extending through the bore and connected to the closure element; a rear surface of the valve stem when the stem is moved axially relative to the bonnet; and a fusible device for unseating the back side of the valve stem, the fusible device being surrounded by a ring of fusible material to seat the ring in the bonnet. a support sleeve for supporting the valve stem, the support sleeve being attached to the valve stem surrounding the valve stem for axial movement therewith;
A valve characterized in that said ring cooperates with said bonnet to prevent axial movement of said unit until dissolution of said ring occurs. 2. The valve of claim 1, wherein the support sleeve includes an outwardly extending radial flange supporting the ring upwardly. 3. The valve of claim 2, including a retaining ring surrounding the valve stem, the fusible ring being interposed between the retaining ring and the support sleeve. (4) the retaining ring includes an annular radial flange;
4. The valve of claim 3, wherein said fusible ring is between said retaining ring flange and said support sleeve flange. 5. The valve of claim 3, wherein said support sleeve and said retaining ring substantially surround said fusible ring. (6) A first bearing device surrounding the valve stem above the fusible ring, the bearing device cooperating with the ring and the bonnet to prevent axial movement of the valve stem. The valve according to claim 2, wherein: (7) A retaining ring surrounding the valve stem, the retaining ring having an annular radial flange between the first bearing arrangement and the fusible ring. The valve according to paragraph 6. (8) The valve according to claim 7, further comprising a second bearing device surrounding the valve stem below the fusible ring. 9. The valve of claim 8, wherein said retaining ring extends axially between said first and second bearing devices to provide axial support. (10) A spring device surrounding the valve stem and biasing the support sleeve, the fusible ring, and the valve stem in a direction axially away from the chamber.
Valve as described in Section. (11) a body having a fluid passageway extending therethrough and intersecting the fluid passageway; a valve-closing element disposed within the chamber for controlling fluid passing through the fluid passage; and a valve-closing element attached to the body and disposed within the chamber; a bonnet having a communicating aperture; a valve stem extending through the aperture and connected to the valve closure element; an annular sealing surface of circular cross-section on the valve stem and an annular sealing surface for establishing a fluid-tight seal between the valve stem and the bonnet; a radial valve seat surface on the bonnet against which a sealing surface rests; 12. The valve of claim 11, wherein said annular sealing surface and said radial valve seat surface are metal to establish a metal-to-metal seal between said valve stem and said bonnet. . (13) Additional valve stem and seal for sealing at normal temperatures.
13. The valve of claim 12 including a bonnet seal arrangement. 14. The valve of claim 11 including a fusible device to keep the valve stem unseated. (15) The fusible device includes a ring of fusible material and a support sleeve that is surrounded by and supports the ring, and the support sleeve is configured to move axially with the valve stem. Claim 14: attached to a valve stem surrounding a stem, said ring cooperating with said bonnet to prevent axial movement of said unit until dissolution of said ring occurs. Valve as described. (16) Claim 15, characterized in that the ring is of a split type and includes two substantially identical semicircular elements.
Valves described in Section. (17) The valve according to claim 15, including a spring device surrounding the valve stem and biasing the valve stem to a rear seated position.