By replacing bearing surfaces with pivots, Spirax Sarco, Inc.'s recently introduced Pivotrol Pressure Powered Pump provides a 3 million cycles by three-year warranty for steam system condensate recovery in rapid cycling environments. An option extends this to a 5 million cycles by five-year warranty.
The unit's patented design uses a hydraulic paddle that acts as a shock absorber to reduce the shock and impact induced from the snap action of a spring linkage mechanism. The spring activates the mechanism, transferring the energy to the inlet and exhaust valves. Eliminating high surface contact areas reduces friction to a minimal level to extend the service life of the unit.
Operating on a pressure displacement principle, liquid condensate enters the pump body through an inlet check valve causing the float to rise. As the chamber fills, a snap action linkage opens the steam inlet valve and closes the exhaust valve, ensuring a rapid change from the filling to the pumping stroke.
When the pressure inside the pump exceeds the total back pressure, this releases condensate through the outlet check valve into the return system and the liquid level falls within the pump. As a result, the float activates the valve changeover linkage closing the steam inlet valve and opening the exhaust valve. With decreased pressure inside the pump body, condensate enters through the inlet check valve to reinitiate the cycle. During the alternating filling and pumping strokes, the float travels freely thanks to a float pivot that prevents constant spring vibration and premature spring fatigue.
The design addresses applications from vacuum systems to heat exchangers, including general condensate return.