The quick assumption when it comes to high temperature pumps is that they’re only meant for high temperature liquids (up to 200°F, in BJM’s case). That’s not always the case. There’s a reason that BJM refers to its Fahrenheit pump as a high temperature AND high endurance submersible pump. The “high endurance” part comes into play when the motor produces its own heat that the pump needs to dissipate that has nothing to do with the temperature of the fluid.
Diagnosing the Issue
Figuring out that you need a high temperature submersible pump for endurance issues isn’t always easy. There are indications that may point you (or your pump supplier) in that direction.
- Water Temperature Isn’t Hot Enough to Cause Issues: You are experiencing premature failures similar to when pumping hot liquid and the pump can’t dissipate the heat. You’ll know it’s an endurance issue if the water temperature isn’t hot enough to cause the issues. In this case, examine the pump itself to see if it is producing the heat.
- Frequent, Quick Duty Cycles: With frequent, quick duty cycles, the motor will start for a minute or two and then shut off. When this happens repeatedly, the motor never reaches a steady state to dissipate the heat within the pump.
- Long, Continuous Duty Cycles: in contrast to the last point, continuous duty cycles are also problematic as the long cycles don’t give the motor a chance to cool, and it continues producing more heat.
Common High Endurance Submersible Pump Applications
These pumps can be used in most industries, but there are applications in which the need for a high endurance submersible pump is more common. Small sumps can cause pumps to have quick duty cycles. If there isn’t enough fluid in the sump to run long enough to reach a steady state, you end up with concentrated heat in certain places of the pump.
Another application is one in which using “dirty” power causes the pump’s motor to heat up. The speed of an AC pump is based on the frequency of the electricity coming into it. Some use a variable frequency drive (VFD) to slow the pump down. The VFD takes AC current and breaks it up. It rectifies the current to DC and rebuilds the sine wave for AC current. This “dirty” power is not as clean as normal 60Hz power, and that makes the motor heat up. VFDs tend to come into play if there are restrictions downstream where you can’t turn the pump on at full speed. It could be pumping from one sump to another, and pumping at full speed overcharges the next sump.
High Endurance Submersible Pump Construction
The construction of the high temperature/high endurance submersible pump is what allows it to endure the motor-produced heat. With standard pumps, the mechanical seal is in an enclosed oil chamber. The oil lubricates and cools the mechanical seal. The high temperature/high endurance pumps have the entire motor chamber filled with a dielectric oil. This helps dissipate the heat formed in the motor windings and conduct it to the motor casing. The heat goes out to the motor casing instead of down the rotor shaft. This prevents the heat from reaching the mechanical seals which have elastomers to hold them in place. When the elastomers get too hot, they melt and fail.
Complex Pumping Solutions
Identifying the need for high endurance submersible pumps requires a deeper level of diagnosis and expertise. Since 1983, BJM Pumps and our highly-trained distributors have helped our customers with complex pumping solutions like this. We work with you to create the right pump solution based on your specific needs, especially in harsh environments. Contact us or call 860-399-5937 for help with solving your submersible pump issues to increase your production and minimize your downtime.