Pump Automation

[EEENGRX]

I have a self primer pump that requires to manually fill up the primer case with prime water to enable it pick up prime and start pumping and avoid damaging the mechanical seal.The pump is used for a sump that i need to automate based on the sump level.i plan to add a foot valve. do you think this will be sufficient to hold prime or it will just reduce the time it takes to prime the pump?what are the various options for shutdown protection or elert to the control room if the pump does not pick up prime for any reason whatsoever? will aan amp monitor at the bucket work? or a solenoid valve on a timer for the priming water which will be activated by the motor starting, per start and close after a set period of time.allauggestions are highly welcome as i want to go with the best possible option as well as less complicated

 

[waross]

Cowboy engineering.
Install an open top tank above the pump.
From the tank drop to the primer case.
Operation.
A timer will open the check valve and allow the water to fill the primer case.
When adequate time has elapsed to fill the case, close the valve and start the pump.
Tap off of a pressure line and feed back to the tank via a restricting orifice.
A small flow will refill the tank and then overflow back into the sump.
Philosophy:
Deliberately prime each start or worry about possible loss of prime?
I choose prime each time.
I like KISS.

what are the various options for shutdown protection or elert to the control room if the pump does not pick up prime for any reason whatsoever?

My first choice would be a flow switch in the discharge line. That depends on cost and the customer's budget.
But, then current monitor relays are not cheap. either.

 

[Compositepro]

A pressure switch is almost always preferable to a flow switch (far more robust). The pressure switch is often wired into the start circuit so that the motor will start when the start switch is pressed but it will not stay latched-on until there is pressure developed by the pump.

 

[waross]

A pressure switch is almost always preferable to a flow switch (far more robust).

At one point I did a lot of Fire Alarm design and installation.
Flow switches were always used to indicate flow.
There was a reason why pressure switches were not suitable, but the flow switches proved their dependability.
It does often take more tooling and expertise to install a flow switch on larger lines as opposed to a pressure switch.
Pressure switches were only used for alarm on loss of supply pressure.

 

[EEENGRX]

A pressure switch is almost always preferable to a flow switch (far more robust). The pressure switch is often wired into the start circuit so that the motor will start when the start switch is pressed but it will not stay latched-on until there is pressure developed by the pump.

Thanks but due to the concern of the pump prime, what would be the best way to effectively prime pump or hold prime before automating the pump. even if the pump is automated and there is no prime . This will lead to pump damage.what do you think?

 

[EEENGRX]

A pressure switch is almost always preferable to a flow switch (far more robust). The pressure switch is often wired into the start circuit so that the motor will start when the start switch is pressed but it will not stay latched-on until there is pressure developed by the pump.

yes good idea but what would be the best way to handle the pump prime. i am looking for a way to handle the prime remotely as well as automate the pump start stop based on sump level

 

[EEENGRX]

At one point I did a lot of Fire Alarm design and installation.
Flow switches were always used to indicate flow.
There was a reason why pressure switches were not suitable, but the flow switches proved their dependability.
It does often take more tooling and expertise to install a flow switch on larger lines as opposed to a pressure switch.
Pressure switches were only used for alarm on loss of supply pressure.

yes i really like those vertical mount float switches for level control but dealing with pump prime and shut down protection is another thing.lookimng for something not too complicated but very effective

 

[waross]

A FLOW SWITCH IS NOT THE SAME AS A FLOAT SWITCH.

 

[waross]

but what would be the best way to handle the pump prime

See post #2.

 

[3DDave]

You have two separate problems. One is that the motor may overheat if it is running but no water is passing through. Use a temperature switch on the motor case for that. The other is if the motor does not run when expected. Use a water level switch in the sump to detect that too much water is in the sump, separate from the water level switch that operates the pump.