A Learning Engineer
New Member
I just finished a project at my first internship/co-op that involves making a pump system automated. Basically, the operator will type in the pressure setpoint, and a variety of devices will work together to increase the pump to pressure. The pump I am using is a Haskal 4b-14 pump. I have a 1/2-inch air line running into a 1/4 in air supply pipe. On the 1/4-inch air supply pipe there is a 3/2 solenoid valve, and an Ip current to pressure transducer. Both have 1/4 inch in and out ports, and the transducer controls the pressure that is going into the pump. On the outlet side of the pump there is crossroad, where many different pipe sizes are, first there is a pressure transmitter that is 1/4 inch, the outlet side of the pump is 1/2 inch so a reducer is needed at the crossroad for it. Then there is a 1/2-inch mechanical relief valve that is inline and goes to the part we are testing. At the bottom of the crossroad there is a pressure gauge, and it is lead to a hydraulic solenoid valve and its ports are 3/8 inch in size. The hydraulic solenoid valve is used as a safety valve if the pressure transmitter detects an overpressure. There is also a fluid supply to the bottom of the pump which is 1/2 inch.
I gave you all of these details because I have only one problem with my system. It has water hammer. When the system pumps up to setpoint and starts holding the pressure, the pressure in the IP transducer stays constant. While either holding the pressure and starting testing time, or when pumping up to pressure, whenever the pump cycles it creates a water hammer effect. The pump cycles and the pressure on the gauge jumps to 100psi over the setpoint for 1 second before returning to its original point.
For example, I was testing the system at 200psi, I started the test and the IP transducer slowly increased pressure until setpoint was met. Once it reached that setpoint, the IP transducer held the pressure constant, and the PLC started its test time. After about 10 to 15 seconds the pump cycles and water hammer occur, the pressure on the gauge spikes to about 280psi sometimes 300psi and then comes back down to around 200psi. My pressure transmitter also reads this and sometimes thinks there is an overpressure, I have a setpoint for overpressure, say 100psi over setpoint then open the hydraulic solenoid valve. This water hammer is not only causing my overpressure device not to work, but also gets dangerous and unsafe as the pressure increases. As I increase the setpoint to let's say 800 psi, the water hammer will be even stronger and the pressure wave will be around 400 psi, which is not good for the system and the part we are testing.
My question is how do I fix this water hammer and why is it happening?
I will go and buy a check valve for the inlet side of the pump just to make sure that no air is creating backpressure and then the pump wants to cycle so it forces a bit more air than it needs to.
Why does the manual version of this system not have water hammer? Manual version uses the same pump but instead of electronic controlled valves and transducers everything is manual, so the operator needs to increase pressure on the regulator and hold it constant. When the pump cycles no hammer head happens, the opposite happens, the gauge on the outlet side of the pump drops to 0 psi for a second then comes back to the original pressure.
Let me know what you think the problem is.
I gave you all of these details because I have only one problem with my system. It has water hammer. When the system pumps up to setpoint and starts holding the pressure, the pressure in the IP transducer stays constant. While either holding the pressure and starting testing time, or when pumping up to pressure, whenever the pump cycles it creates a water hammer effect. The pump cycles and the pressure on the gauge jumps to 100psi over the setpoint for 1 second before returning to its original point.
For example, I was testing the system at 200psi, I started the test and the IP transducer slowly increased pressure until setpoint was met. Once it reached that setpoint, the IP transducer held the pressure constant, and the PLC started its test time. After about 10 to 15 seconds the pump cycles and water hammer occur, the pressure on the gauge spikes to about 280psi sometimes 300psi and then comes back down to around 200psi. My pressure transmitter also reads this and sometimes thinks there is an overpressure, I have a setpoint for overpressure, say 100psi over setpoint then open the hydraulic solenoid valve. This water hammer is not only causing my overpressure device not to work, but also gets dangerous and unsafe as the pressure increases. As I increase the setpoint to let's say 800 psi, the water hammer will be even stronger and the pressure wave will be around 400 psi, which is not good for the system and the part we are testing.
My question is how do I fix this water hammer and why is it happening?
I will go and buy a check valve for the inlet side of the pump just to make sure that no air is creating backpressure and then the pump wants to cycle so it forces a bit more air than it needs to.
Why does the manual version of this system not have water hammer? Manual version uses the same pump but instead of electronic controlled valves and transducers everything is manual, so the operator needs to increase pressure on the regulator and hold it constant. When the pump cycles no hammer head happens, the opposite happens, the gauge on the outlet side of the pump drops to 0 psi for a second then comes back to the original pressure.
Let me know what you think the problem is.
Last edited: