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  • Mirab Co.

Emergency Butterfly Valve with Weight Loaded Hydraulic Actuator

Size (mm) : 300-2500
Pressure rating : 6-40 (bar)
Body Material: All Types of Ductile Cast Iron, Cast Steel, Stainless Steel, Copper Alloys
Disc Material: All Types of Ductile Cast Iron, Cast Steel, Stainless Steel, Copper Alloys

Weight loaded Hydraulic Actuators are used where ever valves installed at critical points of pipe networks have to closed or open in a secure and reliable manner even if failure of external operating energy. they have to meet the most stringent requirements in terms of functional safety. Weight loaded actuator can be used in emergency valves for closing or opening the valve in emergency conditions independent of electrical power.

Application:
Applications of Mirab weight loaded – Hydraulic actuated valves can be classified as follows:
Please note that mentioned application are most important usage of valve and this valve can be used for other applications according to designer opinion.

۱- Combined pump discharge control & non return valve:
Combined function in one valve Starting pumps in a controlled manner and non-return function the actuator helps to start the pump smoothly. Closing slams of the disk is prevented by means of 2 phase closing characteristics. Also the valve can be used as an emergency shut off valve for preventing returning water
to pump station when pipe burst has occurred.
۲- Over flow control valve:
In this case of application, this valve can be installed at inlet of reservoir and can close inlet water pipe for controlling water level , also it can prevent water returning in case of inlet pipe burst occurred.
۳- Turbine inlet safety valve:
Safety valve directly installed at the turbine inlet. It is used as a safety valve for quick closing in case of sudden load rejection, avoiding inadmissibly high speed (runaway speed) of the turbine and water hammer phenomena which might be created there. In a lot of plants, Weight loaded hydraulic actuators are also used in the bypass acting quick- opening devise in order to open synchronously to the closing of the inlet valve in a neutral manner as for as flow rate in concerned
۴- Burst control valve:
In water piping systems, pipe burst can happen due to natural disasters or other reasons like fire, explosion etc. emergency hydraulic valve can be used in system for closing water flow and to protect buildings, traffic routes, pumping stations etc.
۵- Emergency drain valve (Quick opening valve):
Some time water drainage is necessary for protection of systems for instance in a power plant for any reason cooling tower should be drained (to avoid of freezing in winter time) in this situation emergency valve will open and would let to drain all the water.
For applications item 1, 2, 3 & 4 the valve is normally open (when the Weight is up valve is in open situation).
In application item 5 (emergency opening) the valve is normally closed (when the Weight is up, valve is closed)