Automatic Bi-Directional Station Bypass Actuator Control

The “Automatic Bi-Directional Station Bypass Control” module is designed to keep gas flowing in the event there are major compressor problems in a bi-directional flowing pipeline. In instances where a single station bypass valve is used, the typical automatic station bypass control system must be manually reconfigured to change the pressure sensing lines from suction to discharge and vice-versa. This manual reconfiguration presents an opportunity for operational error.

The “Automatic Bi-Directional Station Bypass Control” is self–configuring to provide protection regardless of flow direction. Based on the “Automatic Station Bypass Control” module, the bi-directional system provides ultimate reliability of control action. To achieve this objective, the proven hi-pressure “poppet” valve is combined with a reliable, differential pilot valve to form a stand-alone control module. Opposing sets of pressure-activated check valves route the appropriate suction and discharge signal, depending on flow direction to the sensing inputs of the differential pilot valve. When the differential drops below the adjustable setpoint, pilot gas is passed to the pilot of the “poppet” valve and control action is initiated.

Utilizing the pipeline gas itself, for both the pilot gas and power media, makes the “Automatic Bi-Directional Station Bypass Control” system independent of regulator and other power media failure. The simplicity of design, utilizing minimal components, ensures the bypass valve opens only when required. The “Rate of Drop” (R.O.D.) calibration kit provides for an accurate calibration of the trip point, as well as, the simulation of various operational failure scenarios for testing control action.

The Advantage

• Hi-pressure construction – no regulator, relief valve, or mechanical switching valve.
• Differential pilot valve utilizes a stainless steel diaphragm for accuracy and repeatability.
• Marine-grade, hard-anodized aluminum body for both poppet and differential pilot valves.
• Easily adjustable differential trip setpoint (1.5 psi to 14.5 psi).
• No mechanical linkages, which are subject to environmental failure.
• Limit valve ensures complete opening of bypass valve.