This type sustaining valve is hydraulically operated, diaphragm actuated control valve that sustains min preset upstream (back) pressure and opens fully when line pressure is in excess of setting.
TYPICAL APPLICATIONS Line Fill-Up Control Solutions;Line Emptying Prevention;Systems Subject to Varying Supply Pressure;Infield Filters Backwash Pressure Sustaining ;Energy Saving Irrigation Systems;
FEATURES 1.Line Pressure Driven,Hydrauliclly Controlled *Prioritizes pressure zones *Controls system fill-up *Opens fully upon line pressure rise 2.Engineered Plastic Valve with Industrial Garde Design *Highly durable,chemical and cavitation resistant *No internal bolts and nuts 3.High Flow “Y” Valve Body with “Look Through” Design *Ultra-high flow capacity,Low pressure loss 4.Unitized Flexible Super Travel(FST) Diaphragm and Guided Plug *Accurate and stable regulation with smooth closing *Requires low opening and actuation pressure *Prevents diaphragm erosion and distortion 5.Simple In-Line Inspection and Service
HOW IT WORK
The pressure sustaining pilot valve  causes the main valve to be slowly closed when the upstream pressure [P1] is lower than the min preset pressure,and fully opens when [P1] is in excess of setting.Local manual shut-off of the valve can be performed with the manual selection device.