METHOD FOR DETERMINING THE PRESSURE IN A FLUID THAT IS POTENTIALLY CONTAMINATED WITH PROTEINS, SINGLE USE MEASURING CELL AND TRANSPONDER

摘要

The invention relates to a method for determining the pressure in a fluid that is potentially contaminated with proteins. Said fluid is guided in a pressure-sealed compartment (4) formed in a housing (3) of a single use measuring cell (1). The wall of said compartment (4) has a flexible membrane (7) the edge area (8) of which defines a reference plane (30) and is firmly linked with the housing (3). When the pressure of the fluid in the compartment (4) changes, the membrane is subjected to a perpendicular excursion relative to the reference plane (30). A measurable variable is measured on the membrane (7) using a measuring device (24) and the pressure of the fluid in the compartment (4) is determined in an evaluation device using the measurable variable determined. The aim of the invention is to provide a single use measuring cell (1) which has a simple design and requires less components, which simplifies the measurement of the pressure, thereby saving costs, and which facilitates measuring pressures above and below atmospheric pressure without a transition. For this purpose, the measuring device (24) measures the distance of a measuring point (29) on the membrane (7) from a reference point which is stationary with respect to the housing (3). According to the invention, a single use measuring cell (1) is used the membrane of which consists of a sheet metal. The invention also relates to a transponder, whereby the excursion of the membrane can be measured as a trajectory signal by means of the measuring device (24).