Cyclic pressure test @350psi

[bintomoonjely]

I am new to this group and am currently building pressure testing equipment designed to perform cyclic pressure tests. The maximum pressure I want to achieve is 350 psi in a steel chamber. The system should hold the pressure for 2 seconds and then release it. This cycle should repeat continuously.

I have access to a city water supply with a pressure of 65 psi. My plan is to store the city water in a pressure tank and use a bladder pump to increase the pressure to the desired level. From the pressure tank, a return valve combined with the bladder pump will deliver the required pressure. My question is: can a bladder pump achieve this?

Once the pressure reaches 350 psi, I plan to hold it for 2 seconds using a PLC and a solenoid valve, and then release the pressure. Could anyone help me design cyclic pressure testing equipment? Your guidance would be greatly appreciated.

 

[waross]

Start with a pump unit that is rated to deliver 350 PSIG.
Add a pressure switch and a timer.
Add a solenoid fill valve and a solenoid dump valve.
Start the pump.
When the pressure reaches 350 PSIG, the pressure switch closes the fill valve and starts the timer.
After two seconds the timer opens the dump valve.
Cheaper than a PLC.

 

[bintomoonjely]

I got it, Thank you!

 

[3DDave]

I thought this sort of task is what grad students were for.

 

[btrueblood]

Some thoughts, having done this type of testing innumberable times:

If you don't add some type of damper in the input line, or air space in the device under test, you will likely overshoot the peak pressure using a positive displacement pump.

You need a check valve after the pump (the check valves in most pd pumps get leaky quickly).

Air trapped in the unit under test means you can have an explosive failure vs. a more benign water release for a fully water-filled chamber. That "explosion" may be manageable with suitable barriers and a means to collect the sprayed water.

You should ask the owner of the building it they are okay with you spraying water around if the device ruptures.

The storage tank for the water should be vented to atmosphere if you really want the depth of the cycle to be 350-zero-350 psi. If your supply water is at 65 psig, then the depth of the pressure cycle is only 285 psig (350-65-350). That assume a large pressurized ullage (airspace) in the supply tank. If there is no ullage in the supply, then you might actually suck the supply tank down to a vacuum, cavitating the pump, and not be able to reach 350 psi.

You need a way to count the number of cycles the device under test experiences, so you can have something measureable to report.

You also need a way to automatically stop the test if the device ruptures, if the test runs unattended.

You might also want to think about what happens if there is a power outage if the test is left unattended.