Vacuum limiter ZM-B/L25, SST

Description

Low pressure relief valves control primary pressure (p1, ahead the valve). Low pressure relief valves ZM-B/L25 are controlling protective gas or inert gas to isolate processes from contamination by atmospheric oxygen. The units are practically maintenance.

Technology

ZM-B/L25 is a spring loaded differential pressure relief valve with reference to actual atmospheric pressure via a sensor hole to ambient. Under non operating conditions, the atmospheric pressure and the adjustable range spring close the valve via and a stem. Under operating conditions, gas enters from primary (p1) to the double valve seat and reaches counter side of diaphragm via an internal pulse line as well. So, differential pressure is exactly in balance with atmospheric pressure and the force of adjustable range spring. The valves will be opened as soon as primary (p1) raises set point of adjustable range screw. Valves will be closed with primary (p1) below set point for constant back pressure service. Double valves seats tightness is at least according to VDI/VDE 2174. Option external pulse line is compensating dynamic pressure drop in longer pipes. Best performance with pulse line pick-up directly at process. Optional D-connection is used for pilot line connection in case of dome loaded service (high pressure blanketing). ZM-B/L25 is vacuum-proof, manufactured in decreasing design and uses no external energy.

Application

This vacuum limiter ZM-B/L25 is used to protect vessels and storage tanks against
implosion. With too low pressure, atmospheric air or ventilation gas can be drawn via the regulator.