Pumpsets Ltd designed and built these self priming pump sets for the handling of seawater containing shrimps.
Factory produced low speed self priming centrifugal pumps are not commonly available as most self priming centrifugal pump designs require a minimum rotational speed for satisfactory suction lift operation.
As this particular application requires a relatively high flow,low head pump with reduced impeller speed to avoid damage to the pumped product, the solution in this case is to combine a conventional low shear centrifugal pump operating at a low rotational speed with a separate priming tank.
Constructing the pump end and tank from 316 stainless steel, makes the set suitable for handling seawater at slightly raised temperatures to allow the farming of the crustaceans in a location with normal water temperatures that are generally colder than those found in their typical natural habitat.
This is a simple method to self prime without the need for additional controls and secondary priming devices. Liquid is drawn from below ground. The maximum draw down level is subject to NPSH characteristic of pump. (reference to be made to the individual pump curve). The suction pipe entry is to be submerged at all times to prevent air entrainment and to maintain pump prime. Care is required to ensure an adequate 'Active volume' which is a function of suction pipe volume. If designed and sized correctly with appropriate non return valves, this priming method will allow trouble free, reliable operation with the added benefit of a higher hydraulic pump efficiency, which in turn reduces operational energy costs.
Pump and drive being aligned during assembly.