I assume it's double acting, there is no way it can be anything else. Nowhere on the site does it say this but we can assume it is because of the single piston inside. In the catalog on page 9 under key features it says that the drive pressure can be 3-100 psi so I assume that minimum 3psi from the I/P will still turn the pump. In that case the dump valve needs to be between the pump and the air regulator, correct? (A-E in my diagram) This valve will only be used when depressurizing I think, from my assumptions the pump will stop once the I/p reaches it's set psig value. When we want to depressurize, we energize the 3/2 dump valve which will cut off the main air supply to the pump and also release all air pressure from the pump, while at the same time we open the second dump valve for the water side right? After a couple seconds the system will be depressurized. Is there a specific way I should do this? Should I open both the water side and the air side at the same time, or do they have to be in certain order to not damage anything?
It also says for this pump on the catalog page there can be modifications on it, one of the modifications says "Allows user to regulate drive air to as low as 3 psi (.2 bar)". So I am not sure if the pump can or cannot cycle at 3psi. It says it can do 3psig on the key features but then in the modifications it says it allows 3psi air drive. So, I am not sure if my specific pump has this modification, not sure why its a modification if one of the key features of the pump is 3-100 psi drive pressure. Not I am not sure what to do, I guess test the pump out manually if it can cycle off 3psig air drive.
Edit: After thinking about it more and more there is no need for an air dump valve I think, if the air supply valve is closed and the pump is stopped there is still pressure between the pump and air supply valve. When we want to depressurize the system, we simply open the water side dump valve and the remaining air in between the pump and shutoff valve will be used and then spit out by the pump.
As the water side loses pressure can the pump still cycle or take in air? If this is the case then the dump valve is not needed and the problem I thought I had is gone.
Also @drbitboy in your program the step for starting the pump in subroutine 40 rung #1 says it says to get the HMI setpoint and divide it by 16, then this value is sent to the I/P. This is not starting the pump, right? Also we want to slowly increase the I/P pressure from the start point, not straight to the sp and then increase, I am not sure if the pump can handle an almost instant change in pressure. Would we also want a constant number for this as the start pressure will be the same for each test. Is there a rung I am missing hidden in another subroutine that starts the pump?
It also says for this pump on the catalog page there can be modifications on it, one of the modifications says "Allows user to regulate drive air to as low as 3 psi (.2 bar)". So I am not sure if the pump can or cannot cycle at 3psi. It says it can do 3psig on the key features but then in the modifications it says it allows 3psi air drive. So, I am not sure if my specific pump has this modification, not sure why its a modification if one of the key features of the pump is 3-100 psi drive pressure. Not I am not sure what to do, I guess test the pump out manually if it can cycle off 3psig air drive.
Edit: After thinking about it more and more there is no need for an air dump valve I think, if the air supply valve is closed and the pump is stopped there is still pressure between the pump and air supply valve. When we want to depressurize the system, we simply open the water side dump valve and the remaining air in between the pump and shutoff valve will be used and then spit out by the pump.
As the water side loses pressure can the pump still cycle or take in air? If this is the case then the dump valve is not needed and the problem I thought I had is gone.
Also @drbitboy in your program the step for starting the pump in subroutine 40 rung #1 says it says to get the HMI setpoint and divide it by 16, then this value is sent to the I/P. This is not starting the pump, right? Also we want to slowly increase the I/P pressure from the start point, not straight to the sp and then increase, I am not sure if the pump can handle an almost instant change in pressure. Would we also want a constant number for this as the start pressure will be the same for each test. Is there a rung I am missing hidden in another subroutine that starts the pump?
Last edited: