The chemical-processing market welcomed the first seal-less, seal-free or leak-free pumps around 30 years ago, with their primary purpose being to help prevent the leakage of hazardous materials. At first, a lack of confidence in their functionality, along with high costs, kept these seal-less pumps from becoming standard equipment. But recent technological advances have allowed seal-less pumps to evolve into a reliable and leak-free alternative to traditional sealed pumps.
As seal-less pump technology improved, industrial-pump users began incorporating them in additional applications. Leak-free pumps became commonplace not just for hazardous materials, but also basic liquids, like water. Users recognized that inconvenient leaks, even if they are not dangerous, can lead to costly downtime and potentially expensive maintenance.
Typically, centrifugal pumps are a first-choice seal-less pump technology, but seal-less internal gear pumps have become a favored alternative to traditional centrifugal pumps. While keeping reliability high, seal-less gear pumps can help keep costs low.
Pump Puzzle
Historically, seal-less pumps relied on the pumped product to lubricate the pump’s bearings. Secondary seals were developed to help eliminate leakage, but this created a possibility that fluids required for this system could contaminate the product. Additionally, the secondary fluids would then have to be disposed of, creating extra labor and cost needs.
Seal-less gear pumps were originally designed with a cantilevered load where a large rotor gear is attached to the end of the pump shaft. But even with this design, as hydraulic force is applied, extra pressure is put on the shaft and bearings, which may result in shaft deflections, bearing wear and reduced flow rates and pressure.
Conventional seal-less pumps can also score the pump shaft, causing damage and making it more difficult to seal. Insufficient support of the pumping elements can also cause premature wear of the bushings and close-fitting metal parts. And apart from the high maintenance costs associated with traditional seal-less pumps, potential environmental risks needed to be addressed as well.
The Solution
Keeping all of these potential downsides to the traditional gear pump in mind, EnviroGear® developed a solution with the EnviroGear Seal-less Internal Gear Pump. This new pump builds on the traditional gear pump, but with two major design enhancements: a between-the-bearing support system and one-fluid-chamber design.
Replacing the cantilevered-load design in traditional pumps, the between-the-bearing support system in the EnviroGear pump supports the rotor and idler gears with an eccentric spindle, large diameter materials and large, long radial bushings. This multi-faceted support eliminates the one-sided support typically found in traditional seal-less pumps.
The one-fluid-chamber EnviroGear design places the pump’s magnets on the back of the rotor where they are close-coupled, or “piggybacked” on the rotor gear. This gives the pump a simplified flow path while still allowing for the handling of high viscosity liquids (as high as 50,000 CPS), thin liquids like caustics and even slurries that contain solids.
The EnviroGear Seal-less Internal Gear Pump offers an additional benefit: Versatility. The pump is interchangeable with approximately 95% of the other gear pumps currently on the market and in most systems fits into a traditional sealed pump’s footprint with ease.
Conclusion
The EnviroGear Seal-less Internal Gear Pump, offering simplicity, reliability, and cost-effectiveness, is comprised of only seven primary components: a magnet housing, containment canister, casing, rotor magnet assembly, idler gear, eccentric spindle and head. These seven primary parts are the key to a revolutionary seal-less gear pump that can reduce maintenance time, expenses and environmental costs, all while delivering on the quality that users have come to expect from EnviroGear.