The diaphragm pressure transducer
is a very thin pressure sensor, which is welded from very thin sheet metal into a gas tank. It is vacuum pumped inside and air intake manifold connected outside. The change of pressure outside the diaphragm makes it expand and contract. When the diaphragm box receives positive pressure, such as atmospheric pressure, the wall of the diaphragm contracts after compression. To measure the absolute pressure of the intake manifold, the pressure chamber of the diaphragm box can be connected with the intake manifold of the engine.
When the pressure of the intake manifold changes, the diaphragm box shrinks or expands, making the joystick extend or retract. The action of diaphragm box makes the movement of control rod and the change of absolute pressure of intake manifold linearly. The mechanical motion of the diaphragm box can be converted into electrical signal output by using three devices: variable resistor (potentiometer), variable inductor and differential transformer.
When the diaphragm moves, it drives the joystick to move. The diaphragm passes through the differential converter, which converts the diaphragm into resistance change to form electrical signal output. The working principle is similar to the smoke limiter on the mechanical high-pressure pump.
The pressure of the measured medium enters the inner chamber of the diaphragm box from the joint, and the free end of the diaphragm box is pressed to produce displacement. The core gear is driven to rotate by the connecting rod mechanism, and the measured pressure is indicated by a pointer on the dial. It is used to measure the micro pressure on the equipment of boiler ventilation and gas pipeline. The pressure gauge of diaphragm box can be installed on site and indicated on site.
The diaphragm pressure transducer can drive the electronic sensor according to the change of pressure.