Method for setting the delivery capacity (pumping capacity, pump horsepower) of a liquid recirculation pump (recirculating pump, return pump)

摘要

A method is specified for setting the delivery capacity of a liquid recirculation pump which can be driven by a variable-speed electric motor and is arranged in the piping system (conduit system) of a heat treatment installation. The speed of the electric motor is controlled by a controller which is fed as input variable an electric voltage which is proportional to the flow velocity of a medium moving in the piping system of the heat treatment installation. As output variable for controlling the speed of the electric motor, the controller delivers electric voltage values which are higher for each flow velocity of the medium in the piping system than the voltage values which correspond to the impressed and calculated piping network characteristic of the heat treatment installation. The outside (external, ambient) temperature prevailing at the building in which the heat treatment installation is located is fed together with the feed temperature of the medium in the piping system as further controlled variable to the controller. In order to minimise the energy requirement, the feed temperature is continuously set by the controller to values for which the liquid recirculation pump is operated at optimum efficiency.