Is a flow inducer on 4" pump really needed with large holding tank?

[hamlet_jones]

Hiya,
Application is large holding basin, with 4" deep well pump. I've heard of shrouds or inducers for
a vertical install, to help suck water from off the end of the motor, to get every last drop out of
the tank, but do you really need it for cooling if the volume of water is 500 gallons, and 4o deg
fahrenheit?

 

[Valveman]

The motor company will tell you a shroud is not needed, but they sell motors. It is not the amount of water in the tank, but the flow of water past the motor that counts. Even 40 degree water will get to 212 real quick if it is just sitting against the motor. Depending on how the flow is coming into the storage tank, and how it swirls around in the tank, there maybe no flow close to the motor. You can be pumping 40 degree cold water out the discharge while water is boiling just a couple feet below on the motor.

I learned in my injection molding stuff that turbulent water draws more heat away from metal than laminar flow. So just the water rushing past the motor makes it more turbulent and draw more heat away. A shroud is just a easy/cheap way to not have to worry if the motor has proper cooling flow. But you need to lay it on its side of you want to get the last few inches of water from the storage tank. The shroud is not perfectly sealed at the top and you will still lose prime when the water level gets to the suction height. But laying them on the side is fine, and the shroud then actually holds the motor off of the cradle.

 

[Sponsor]

 

[hamlet_jones]

Thanks! I get it. I laying on it's side, I need a 2nd check valve, spring loaded ball, swing, and what position?

 

[Reach4]

swing

Swing? What is that?

 

[hamlet_jones]

Swing, as in swing-check valve.

 

[VAWellDriller]

Swing checks belong in the garbage can...put a spring loaded poppet style check, vertical preferred.