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Low pressure stem gas seal

A technology for sealing components and valve stems, which is used in shaft seals, valve details, valve devices, etc., and can solve problems such as inability to achieve sealing capabilities.

Inactive Publication Date: 2006-11-08
BAKER HUGHES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One reason for this is that exposure to flowing fluid as well as temperature cycles over time can move the o-ring to a position where it cannot achieve its sealing ability

Method used

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  • Low pressure stem gas seal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0012] Referring to the drawings, a valve stem 10 extends through a valve cap 12 . The stem 10 has a lower end 14 to which a gate (not shown) is attached. The bonnet 12 is secured to the valve body (not shown) by bolts (not shown) that extend through threaded holes 16 . Groove 18 holds a seal (not shown) to allow sealing of bonnet 12 to the valve body. A main stem seal 20 is retained between the stem 10 and the bonnet 12 in a known manner.

[0013] As shown in the enlarged view, the bonnet 12 has a tapered surface 22 which contacts a mating surface 24 which may be parallel or non-parallel. Although the orientation of the surfaces 22 and 24 is shown as being inclined relative to the axis 27 of the valve stem 10, those skilled in the art will understand that a vertical orientation is also contemplated by the present invention. A generally U-shaped groove 26 is shown within surface 22 . Although only one groove 26 is shown, those skilled in the art will appreciate that more t...

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PUM

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Abstract

A backup stem seal for a gate valve retains pressure in the body when the valve is in the closed position. The backup seal is secondary to the main stem seal assembly (20) in the bonnet (12). It features metal-to-metal contact between surfaces (22, 24) that are radially oriented or sloping and further can contain a retaining groove (26) for a seal ring (32) in one or both the opposed metal-to-metal surfaces (22, 24). The groove (26) can be formed to better retain the ring (32) from damage from flowing fluids when the valve is open. A passage through the bonnet (34) may be used to test for leakage past such seal. The backup seal allows maintenance of the main stem seal (20) without removing the valve from service.

Description

technical field [0001] The present invention relates to a valve stem seal and, more particularly, to a back up stem seal for a gate valve designed to maintain fluid pressure within the valve body. Background technique [0002] Gate valves are commonly used in the oil and gas industry. The American Petroleum Institute (API) has established a standard for gate valves, called Standard 6A. [0003] Typically, gate valves feature a gate operable within a body that rises against a valve seat, closing the valve. A valve stem is attached to the gate to move the gate up and down. The valve stem may be operated manually, such as with a hand wheel, or the valve may be operated automatically by an actuator controlled by a control system that detects changes in the system in which the gate valve is installed. Gate valves are frequently used for opening or closing operations and are not the preferred design for throttling applications like restrictors, where other valve types are contr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F16K41/14F16K31/44F16K43/00
CPCF16K41/14F16K43/008F16K3/02
Inventor 格兰特·R·汤普森艾伦·T·杰克逊
Owner BAKER HUGHES INC