I’m working on a testing setup that requires the generation of pulsatile flow at frequencies around 50 Hz. Initially, I considered using solenoid valves for this purpose, but due to mechanical limitations(of plunger unable to move 50 times up and down in a second) as told by various suppliers , they seem unsuitable for achieving the required frequency.

I'm looking for alternative solutions that could help me achieve consistent and precise pulsatile flow at this frequency. The system involves liquid as the working medium, and I’m aiming for high reliability and durability in operation.

If anyone has experience with high-frequency flow control or can suggest viable alternatives. I would appreciate your insights.

 

Manifold with a compliant wall (diaphragm) actuated by a moving coil actuator (like a speaker)
feed in a steady flow, get a pulsating flow out.

Like a giant version of an ink jet printer

 

Depending on performance parameters, concerning time-to-valid-pulse-rate, a peristaltic pump might be a solution. Even if you do have a tight requirement for speed of availability, you could probably leave the pump spun up and use a solenoid valve to get the flow.

If you don't need control of duty cycle, a peristaltic pump could be designed easily with a 3D printed cam on a stepper or brushless motor, and latex tubing. You could vary the pulse rate easily enough, with a frequency dependent duty cycle but if you design the cam for your target rate, it would have whatever pulse width you choose.

 

My experience with flows has been reducing the flow pulsations not causing them. This is an interesting question indeed. What will cause a pulsating flow is a vane pump with a minimum number of vanes, or even a vane pump with alternate vanes removed, and the intake flow restricted. A dirty filter caused that problem in a test stand once is how I am aware of it. So for the TS application a servomotor driven vane pump with a flow rating near what the TS requires, and with the speed set to give a 50hZ vane ripple frequency could be the solution, depending on how much flow ripple is required for the application.

 

Consider that for 50 HZ pulses, which are not defined as to magnitude or flow, BTW, if the peristaltic pump delivers two pulses per revolution that will mean 25 revolutions PER SECOND, and 1500RPM. That is reasonable for a gear pump or a vane pump, and possible for a piston pump, but not imaginable for a reasonable peristaltic pump, which mostly run much slower.
Really, though, a one cylinder, small displacement, piston pump will be able to deliver a "sort of square" pressure pulse square wave fairly well, if the flow requirements are not excessive.

 

I recollect something similar that used a cam-driven stainless diaphragm. It depends on the volume to be moved, but a cam can spin fast and move a lot of power.

 

I recollect something similar that used a cam-driven stainless diaphragm. It depends on the volume to be moved, but a cam can spin fast and move a lot of power.

For any stainless steel diaphragm pump, be sure to understand both the lifetime of the diaphragm and the consequences of it's failure leakage flow.

 

Depending on what you need this to do, I recall a couple guys at a field site had a test stand that used car fuel injectors to get very precise specific water pulse timing/flow for a mid-pressure system. They weren't trying to get huge flows rather very precise flows and pulse rates. I recall it worked really well once they got their power supply balanced out for the timing. I recall they only spent about $250 for it, most of which was power supply and controller.

 

What we do not have at all is an explanation of the pulse amplitude or shape. ALL liquids have a lot more inertia than electrons, and so the pulses will not be "square waves" like we have with electricity. In addition we really need to know the pressure and the flow. At best there will be a rise time and a fall time.
If the fluid is compatible, the closest standard scheme will be a direct action hydraulic servo valve.