Low pressure dew and frost point indicator

摘要

A low pressure dew and frost point indicator of the type having a vortex tube which directs a cold air stream against the back of a viewing mirror for observation of the initial formation of frost. The mirror has means for simple and automatic centering with respect to the cold air stream of the vortex tube for maximum temperature transfer. The mirror engages no heat conducting elements and has means for improved cold temperature transfer. A venturi nozzle passes the warm air output of the vortex tube around the cold air output for adjustment to provide optimum cold air generation by reduction of the vortex tube outlet pressure. A temperature control valve controls the temperature in the sample chamber by mixing the warm and cold air outputs of the vortex tube.