Sleeves help direct water flow to properly cool motors.
Submersible pump motors require water flow over them to dissipate heat. In open water, such as a lake or water tank, or in large diameter wells, heat dissipation becomes a problem since water is likely to flow directly into the intake of the pump, instead of flowing over the motor. In these situations, a pump sleeve or shroud is required. Pump sleeves are also required if the well is top feeding (water flows in from above), or if the pump is placed below screens or perforations, and sand is able to fall into the pump inlet. As a side note: pump sleeves, flow sleeve, flow inducer sleeve, and pump shroud all mean the same thing!
A pump sleeve is simply a PVC pipe that prevents water flow into the pump from the lateral directions, and directs waterflow to enter from the motor's end, allowing for water to pass over the motor first before entering the intake.
Pump sleeve kits are available to help simplify assembling a complete pump sleeve. These kits do require a PVC pipe, which are available at your local hardware store. Just be sure to have the pipe cut about a foot longer than your assembled pump.
Below is a chart for minimum flow rate required by the motor per well casing diameters. If your pump operates at a lower flow-rate than stated, you will require a pump sleeve.
| 4 inch motor | 6 inch motor | |
|---|---|---|
| Well casing diameter | Min. GPM | Min. GPM |
| 4 | 1.2 | |
| 5 | 7 | |
| 6 | 13 | 9 |
| 7 | 20 | 25 |
| 8 | 30 | 40 |
| 10 | 50 | 85 |
| 12 | 80 | 140 |
| 14 | 110 | 200 |
| 16 | 150 | 280 |