Pneumatic pressure transmitter responsive to temperature and humidity

A force-balance pneumatic pressure transmitter responsive to temperature and humidity comprising:

• a nozzle;
• an inlet for conducting a restricted supply of fluid under pressure to said nozzle;
• a flapper operatively associated with said nozzle to vary fluid flow through the nozzle;
• a first pivot displaced from said nozzle;
• a first elongated resilient simple beam supported at one end upon said first pivot and connected at the other end to said flapper;
• a first abutment associated with said first beam and located between said nozzle and said first pivot biasing said flapper toward said nozzle through said first beam;
• a second pivot displaced from said nozzle;
• a second elongated resilient simple beam supported at one end upon said second pivot and connected at its other end to said flapper;
• a second abutment associated with said second beam and located between said nozzle and said second pivot biasing said flapper toward said nozzle through said second beam;
• first means for applying a bending moment to one of said beams in response to sensed temperature;
• second means for applying a bending moment to the other of said beams in response to sensed humidity, said first and second means acting together to apply a variable control force through said first and second beams to said flapper to modulate said fluid pressure in response to the sensed temperature and humidity, said fluid pressure acting over the area of the nozzle to provide to the flapper a negative feedback force proportional to said fluid pressure.