Flow Control Valve

[ayoung802]

I am using a sequence valve with two cylinders, 1 small cylinder and 1 large cylinder. In order to extend the large cylinder in a reasonable time I have to have a large flow rate. The problem is the flow rate will be too high for the smaller cylinder. So my question is how can I slow down the second cylinder? My initial thought is to use a couple of flow control valves, but I am concerned they will affect the sequence valve in some way.

This is a side question to the main one. How does a flow control valve reduce flow? Intuitively I would say pressure builds up on the inlet because less fluid is allowed through. However looking at Bernoulli’s P1+(1/2)*p*V1^2=P2+(1/2)*p*V2^2 would say otherwise. It says that the inlet with a higher flow rate would result in a lower pressure in order for the output to have a lower flow rate, but a higher pressure.

A little help would be appreciated.

 

[hydtools]

A two-port or blocking flow control forces excess flow over a relief valve. Input pressure rises to relief pressure to pass excess over relief or raises the variable pump control pressure to reduce pump stroke to desired flow.

A three-port or bypass flow control meters flow to the load and passes excess flow to the bypass port to tank. Metered flow is controlled by maintaining a differential pressure across the metering orifice. Input pressure is the sum of load demand pressure and the control differential pressure.

Excess flow has to go somewhere or not be generated.

Ted

 

[roydm]

And if it's an air cylinder you throttle the exhaust not the air supply.
Roy

 

[JLSeagull]

Devices often called speed controls have a check valve in parallel with a needle valve. These adjust the flow in one direction without impeding the other direction. You could use such speed controls for each direction of travel on both cylinders and adjust to match the speed or select the faster action.

 

[Unotec]

Answer to your Bernoulli question, the volume does not change unless you reduce the pipe's diameter, where the pressure would be reduced.

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