What is the difference?
Back pressure valves ( Also termed loading valves/pressure sustaining valves ) help stabilize the downstream pressure from a pump or varying head height. Back pressure ensures that certain types of pumps, many reciprocating metering/dosing pumps output consistent flows. They do this by applying a minimum constant pressure that a pump has to push against to maintain reliable check valve seating (closing). Consistent closure of its suction and discharge check valves on reciprocating pumps (like a diaphragm or plunger pump) allow for higher accuracy and stable operation.
Anti-siphon valve is different from a check valve. Although they are a normally closed valve, they have a very important function and feature that operates differently than most types of valves. They ensure the liquid continues to drain or empty. This can happen when siphoning occurs (Venturi effect). This is where the fluid is pulled (sucked) out of the pipe. These types of valves seal better with more suction applied. The valve stops liquid from flowing when upstream pressure is no longer applied. Griffco’s back pressure valves operate as an integral anti-siphon valve.
Pressure relief valves protect expensive capital equipment such as the pump, system, or tank from an upset condition (pressure spikes, over pressurization, a closed valve, etc.). They are a normally closed valve that operates (opens) when the pressure exceeds the preset value. They allow the excess pressure to be bypassed and safely discharged into a reservoir or back into the inlet piping. They maximize the uptime and ensure proper function for all ancillary devices connected. Griffco has the widest range (size and flow) and the most options, as well as custom engineered valves available.