There are two main types of pressure control valve function, direct acting and pilot or pressure assisted.
Pressure Sustaining (also known as BPV back pressure valve), Pressure Reducing Valve (PRV) and Safety Pressure Relief valves utilise the pressure difference between the inlet and outlet ports to move the main gate into position via an small external pilot control valve.
The external control valve can be removed, exchanged for different operation, pressure adjusted or simply removed for easy handling, transport and installation of the valve main cylindrical body. This unique Patented compact cylindrical valve body has a rugged internal piston with U ring seal offering exceptionally good sealing, durability high flow and long maintenance free life. Typically available from DN50 to DN1000 flange with NBR or Viton sealing manufactured from either Bronze, Ductile Iron with Epoxy coating, Cast Iron, 304 and 316 stainless steel construction for the control of water and non-aggressive or corrosive fluids, gases and for stainless steel can include steam and pure water media applications.
Direct acting pressure control valves operate directly and do not reply on working media pressure differences to operate. Typically available 316 stainless steel, Bronze, Cast Iron and Titanium from ½” through to 2” BSP G, NPT or PT thread or Flange DN50 to DN150, optional NBR or Viton sealing to suit most water, pure water and non-aggressive media applications, with special PTFE sealing for special media applications.
will reduce and maintain a stable outlet pressure regardless of inlet upstream pressure changes. Pressure can be adjusted between minimum and maximum pressure settings with the outlet or downstream pressure displayed by a pressure gauge. Example valve outlet pressure set to 5 bar, outlet pressure will remain at 5 Bar even if inlet pressure fluctuates between 5 Bar to 15 Bar.
will maintain a minimum back pressure regardless of downstream demand. Pressure can be adjusted between minimum and maximum pressure settings and sustained back pressure displayed by pressure gauge. Example valve back pressure set to 4 bar, if pressure drops close to 4 bar valve will slowly close to maintain the back pressure and will open again when back pressure recovers.
Safety pressure release or relief valve is designed to stay closed until the inlet upstream pressure reaches the set limit at which point it will quickly open and release over pressure. When pressure returns within safe limit safety valve will slowly close again. Inlet system pressure will be displayed by pressure gauge.
Pressure reducing, sustaining and relief valves are typically offered with minimum and maximum working pressures and a maximum design pressure. For example the control pressure required must be within (ideally in the middle) of the valve adjustable range (min max) AND the valve maximum design pressure must exceed the maximum possible system pressure of the application.
Most water control valves are fitted with NBR Nitrile Buna Rubber seals which are ideally suited for water applications, Viton is an option for slightly aggressive media however it is best practise to check with your supplier beforehand especially when working with corrosive and aggressive acid and alkali media requiring more specialised PTFE sealing.
Micro Pressure Reducing Valves
Low pressure reducing valves series: RELT + RELF
Pressure Gauge shows reduced downstream pressure
Pressure reducing valve PRV series RET
Pressure reducing valve PRV series: REF
Pressure Sustaining Valve Z-Tide Series: RFT
Pressure Sustaining Valve Z-Tide Series: BFS
Pressure Relief Valves Z-Tide Flanged series: RLF
Z-Tide AIT + AIF Inline Series Water Hammer Arrestors
Z-Tide AXT L Series Water Hammer Arrestors