Method and device for measuring the gas concentration of a liquid plastic component

摘要

For measuring the gas concentration of a liquid plastic component for the production of polyurethane foam materials, a sample is extracted from the main quantity of the plastic component and led into a piston-cylinder unit (4). The sample pressure is subsequently measured and the volume of the probe is changed from a first volume to a larger second volume. For this purpose, the piston (8) of the piston-cylinder unit is moved hydraulically from a first position into a second position. During and/or after the expansion of the sample, it is exposed to a shear field of 0.5 to 1000 sec<-1> with the aid of a stirring element (12) projecting into the cylinder (5). By means of the shearing of the sample, the desorption of the gas dissolved in the component is started or accelerated, so that the subsequent pressure measurement also takes into account the proportion of gas dissolved in the component. From the difference value of the pressure measurement, the actual gas concentration of the component may be determined. <IMAGE>