Liquid density transducer - measures axial displacement of diaphragm in two-part shell with reference liquid and two membranes

摘要

A densimeter for liquids such as wort during the fermentation process in beer breweries is a water-filled shell which is divided by a horizontal diaphragm into two parts, each with a connection closed by a membrane. when immersed in wort, a force must be exerted by the diaphragm to keep it in equilibrium against the static pressure difference of the membranes. This is done by an electromagnet. The axial displacement of the diaphragm is sensed and converted into a control signal for the current in the electromagnet coil to keep the air gap of the electromagnet constant. This current is a measure for the difference in density between outer and inner liquid. This measures the density of greatly polluted pasty or fermenting liquids in a simple way, yet produces continuous results with a high resolution. The instruments are robust enough for brewery use and require only an electrical cable for the installation. The densimeter can easily be cleaned and disinfected automatically. After slight alterations, it can also be used to measure pressures, pressure differences or fluid levels.