Pilot-operated valves

|   Know how

SAMSON's large-sized self-operated regulators are also used in district heating and cooling applications to control the temperature, pressure, differential pressure and flow rate as well as to monitor the pressure and temperature for safety reasons. They provide a high dynamic response and small system deviations.

    The principle of operation of the self-operated regulators manufactured at SAMSON is based on a comparison of forces. Friction forces or forces created by the pressure drop at the valve plug impair the valves' control behavior. Consequently, the pressure-balancing mechanism plays a key role in the valves. Pressure balancing counterbalances forces acting on the valve plug, which are created by the medium flowing through the valve. As a result, the regulators work without being influenced by changes in the pressure drop across the valve, they can shut off tightly even at high differential pressures and they can be manufactured in large valve sizes as well.

      Energy Efficiency with Large-sized Valves

      Example: district heating


      Example: position transmitter with temperature closed-loop control upon failure

      Example: district cooling


      The requirements placed on the modern electric valves can also be met by self-operated regulators in sizes up to DN 400 fitted with a pilot valve to work as a control unit. Specially engineered control units are used in heating and cooling circuits, which combine pressure reducing valves, excess pressure valves and regulators for differential pressure and/or flow rate control together with electric pilot valves on which TROVIS 5824-8 Electric Actuators with Process Controller are mounted. As a result, the functions provided by self-operated regulators are stretched even further, for example:

      • Differential temperature control with return flow temperature limitation
      • Communication connection using RS-485 two-wire bus with Modbus RTU protocol
      • Fit for Industry 4.0 using SAM DISTRICT ENERGY Asset Management System

      Cloud topology with gateway for bus connection

      Cloud topology with PLC and bus connection