Fisher 2625 Series Original for Control Valve 10.3 Bar Sil 3 Aluminum Stainless Steel Volume Booster

1. Description

    A Fisher 2625, 2625SST, or 2625NS volume booster is part of the 2625 Series volume boosters and is used in conjunction with a positioner on a throttling control valve to increase stroking speed. The 2625NS is a nuclear‐service version and uses elastomeric components that better withstand high temperature and radiation environments. The booster incorporates fixed deadband, soft seat construction, and an integral bypass restriction to eliminate positioner saturation problems that can occur with volume boosters that do not have these features. Adjustment of the integral bypass restriction is necessary for system stability. This adjustment does not affect the deadband of the volume booster, but does permit the control valve to respond to small input signal changes without sacrificing steady‐state accuracy. It also allows the booster to deliver high‐volume output for fast stroking when large, rapid input signal changes occur.

2. Specification