Dosing pump provides 99% accuracy for milk processor

London -  German engineering company seepex has installed a specially adapted progressive cavity pump for the production of the powdered milk protein caseinat an unnamed major Irish milk processor. The pump, which is designed to precisely dose dilute hydrochloric acid into the liquid milk stream, is sited close to the milk storage tanks and pumps the acid to a nozzle in the milk pipework where it is injected into the milk stream.

According to supplier, the pulsation-free pump removes the need for expensive dampeners, which are usually required with traditional diaphragm, piston or peristaltic metering pumps. Due to the corrosive nature of the acid involved, the internal metal parts of the pump are manufactured from chemical resistant Hastalloy, while the pump casing is made of Halar-coated cast iron.

Pump speed is varied by a frequency inverter and a probe in the milk stream that measures the pH. Changes in the pH of the milk stream result in a corresponding change in pump speed to provide a control loop that maintains a completely constant pH within the milk stream, added a seepex statement.