In the world of all things pumping, many frustrated pump rental companies and service and equipment providers have to walk away from certain jobs because they just don’t have the technology to do it right. One of the most common sources of these lost opportunities results from not having an answer when customers need to pump hot liquids.
In cases where fluid temperatures approach 200oF or 95oC, there are few options, especially when the TDH requirements call for using a submersible pump. The fact is that most electric submersible pumps, because of built in protections, will only perform in these conditions for short periods of time before they experience thermal overload and thus shut down for a cooling period. With the pumping action stopped, downstream processes cease, or the upstream influx of hot fluid overcomes the sump or storage vessel, resulting in work stoppages or overflow conditions.
Any savvy business person knows that effectively solving a problem like the on described can open up new customer bases and revenue streams. So, who has the cool answer to this hot question?
To solve this riddle, it is first important to understand the other critical components of a pumping system that must be considered. Beyond thermal overload in motors, the pump’s materials of construction, including the elastomers in mechanical seals, O-rings and gaskets and other non-metal parts must be equal to the task. In the world of sealing materials, the most common “rubber” compound used is nitrile/Buna, and depending on the manufacturer, these pieces are rated to hold their sealing properties up to 210oF (99oC). EPDM and FKM gaskets and seals can offer an extra measure of protection since they are rated for temps up to 250oF/121oC and beyond. Because most pumps made have one of these three seal types built in, this part of the systems offers minimal cause for concern. Then, any wetted part of the pump that contains plastic, including the insulation on wiring must be studied. Because different types of plastic begin to distort at different temperatures, failures could result if the resin compounds inside the pump cannot take the heat.
Armed with the knowledge of what to look for in a workable hot liquid pump, you should consider the hydraulic submersible equipment manufactured in Pennsylvania by Hydra-Tech Pumps.
Hydra-Tech’s submersible pumps, built on non-electric, hydraulic drive technology are not subject to electric motor based thermal overload, and because they have the correct elastomers in the seals and O-rings and because there are no plastic parts, these pumps are built to beat the heat, with one note of caution.
Anyone used to working with hydraulics knows that heat in hydraulic oil is the mortal enemy of any hydraulic system. And, since our pumps are designed to be submersed in the hot liquid, the oil flowing through the pump motor is seeing and absorbing some of the heat from the hot fluid. To minimize the effects of this exposure, we have engineered in to most of our hydraulic power units Air over Oil hydraulic oil coolers which use ambient air flow to remove a lot of the heat. In cases where the pumping job is continuous, or when ambient temperatures are elevated, there is still a chance that the standard on board cooling may be overcome. In these cases, additional cooling methods, from simple to sophisticated, can be employed to make sure oil temperatures remain below 160oF/71oC.
In a temporary situation, it can be a simple as removing heat by putting an extra length of hydraulic hose in to a fresh water bath. If the customer is uncomfortable with that kind of fix, you can reach out to our engineering staff, and we can look at adding additional cooling at the hydraulic power unit. The options here include swapping in a larger oil cooler or building in a dedicated fan assisted oil cooler. In cases where the installation is permanent or semi-permanent, and where a fresh cooling water source is available, a highly efficient tube and bundle type oil cooler can be employed.
So, before you dismiss hot liquid pumping jobs and the new revenue streams they may offer, give Hydra-Tech Pumps a call and we will be happy to help you evaluate the job and come up with a pumping solution.