Multi-valve stem seal assembly for a gate valve

Abstract

A gate valve for use in oil field applications and including a stem seal assembly. The stem seal assembly includes primary, secondary, and tertiary seals for sealing the space between the stem and the bonnet. The provision of multiple seals in the stem seal assembly provides redundancy that allows for maintenance of the seal between the components even if one or two of the individual seals fail.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 61 / 747,749, which was filed Dec. 31, 2012, the full disclosure of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This technology relates to oil and gas wells, and in particular to seals in gate valves used in oil and gas field applications.[0004]2. Brief Description of Related Art[0005]Typical gate valves used in connection with oil and gas operations have a valve body with a flow passageway that extends therethrough. The flow passageway intersects a central cavity, where a gate is located. The gate has an opening, and moves between open and closed positions. When in the open position, the opening is aligned with the fluid path so that fluid can flow therethrough. Conversely, when the gate is in the closed position, the gate blocks the flow passageway. The gate is attached to a stem, which...

AI Technical Summary

Benefits of technology

This patent describes a sealing device used in high-temperature and high-pressure environments. The device has two parts: a primary seal and a secondary seal. The secondary seal is located between the stem and the extended portion of the primary seal and is designed to seal against these surfaces. It also has an anti-extrusion ring to maintain its shape and prevent it from being affected by heat or pressure. Additionally, there is a metal standoff ring to restrain the secondary seal from moving too far. This design ensures the sealing device is effective and reliable in extreme conditions.

Problems solved by technology

However, since elastomeric seals do not have the necessary longevity, especially in corrosive environments, or the ability to withstand high temperatures and pressures, metal seals have become popular.

Metal seals, however, have their own problems, including premature wear, damage to the scaling surfaces, and insufficient sealing capacity under certain conditions.

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