Method and control unit for pumps arranged in series

Abstract

The invention relates to a method and an electronic control unit for a set of rotary pumps (1, 2, 3) arranged in series. This set comprises at least one upstream rotary pump located directly upstream of a downstream rotary pump. According to this method, the rotational speed of the upstream rotary pump and the degree of opening of a control valve of the upstream rotary pump are controlled as a function of a saturation margin of the downstream rotary pump and a flow coefficient of the upstream rotary pump. The saturation margin of the downstream rotary pump is the difference between the current pressure and the saturation pressure of the liquid at the inlet of the downstream rotary pump. The flow coefficient of the upstream rotary pump is the volumetric flow rate of the upstream rotary pump divided by the rotational speed of the upstream rotary pump. Fig. 1.

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