Hot water circulating pump without external cooling
Beginning of May, KSB Aktiengesellschaft, Frankenthal, is launching a new generation of hot water circulating pumps for large, industrial-scale heating systems, forced-circulation boilers and district heating systems.
The HPK-L type series, consisting of 21 different pump sizes, is suitable for operation at a working temperature of up to 230 °C without additional cooling and is designed for PN40. Its impressive temperature resistance is due to the generously dimensioned heat barrier which separates the hot operating area of the unit from the air-cooled seal chamber of the mechanical seal.
The large cooling fins surrounding the seal chamber are cooled by a continuous flow of air supplied by the fan impeller mounted on the tip of the pump shaft. Large product-lubricated ceramic bearings mounted in the impeller area, as well as duplex angular contact bearings sealed on both sides and fitted on the „cold“ shaft end, make for a service life of at least 25,000 hours.
The impellers are equipped with back vanes in order to reduce the axial thrust and relieve the shaft seal. The pump casing is a double volute, which greatly reduces the radial forces generated by the fluid flowing through. The hydraulics geometry is that of a standardized chemical pump: it has the same excellent efficiencies and low NPSH values. Thanks to a patented dirt-repellent groove in the discharge cover, dirt particles entrained by the fluid are kept away from the plain bearings. The new HPK-L series is fully compatible with the standard HPK, so that the air-cooled bearing bracket can be retrofitted whenever the need arises.
Source: KSB SE & Co. KGaA