ZDT series automatic recirculation valve

ZDT series automatic recirculation valve is a kind of pump protection device. It automatic protect centrifugal pump when pump body occur cavitation damage or unstable (especially conveying hot water at low load operation medium). Once pump flow is lower than the preseted flow, bypass can completely open to ensure the minimum required flow pump. Even running fully closed, namely running flow is zero, the minimum flow can also pass bypass for Automatic Recycle. Pressure reduced through the multistage bypass pressure reducing valve.
ZDT series has big bypass, and this valve is suitable for bypass with big flow, maximum pressure differential is 4MPa, specific choice is determined by factory.


  • Simple structure, operation reliable and stabile, with few movement parts.
  • Be easy for installation, can be installed vertically or horizontally on pump pressure outlet.
  • Bypass flow is large, maximum flow is 60% of main flow, KV value can be adjusted.
  • Maximum bypass operating pressure differential is 4MPa. Bypass non-return function is optional.
  • Applicable medium including: water, oil, methanol and other liquid medium.
  • -196℃ to + 300 ℃ . Diameter and pressure range

Valve body type: three-way casting valve

  • Nominal diameter: DN25, 32, 40, 50, 65, 80, 100, 200, 250, 300, 350, 400
  • Nominal pressure: PN 16, 25, 40, 64, Class 150, 300 L , etc.
  • Connection type: flange FF, RF, RTJ, BW, SW etc .