Working principle of double bellows differential pressure gauge
Structurally, the double bellows differential pressure gauge is mainly composed of two bellows, a range spring, a torque tube, and a casing. It has a central base 18, and bellows B1 and B2 are installed on both sides of the base. There are rigid end caps at both ends, and are rigidly connected by connecting shaft 5 to form a whole. High pressure and low pressure measurement chambers are formed between the outer sides of the two bellows and the housing, respectively. In order to compensate the error caused by the temperature change, a temperature compensation bellows B3 is connected to the bellows B1 on the high pressure side. distilled water and 50% ethylene glycol), sealed for a long time. B1 and B2 communicate with each other through the ring gap between the damping ring and the central base and the damping bypass. In the low-pressure chamber, a range spring is installed between the center base and the free end of B2, and a baffle is installed in the middle of the connection, and the left side of the baffle is close to a miniature ball bearing installed at the lower end of the swing rod. The upper end of the swing rod is fixed on the torque tube, and the mandrel of the torque tube is connected with the instrument pointer system to drive the pointer to rotate.
When the pressure p1 and P2 of the side medium are respectively introduced into the high and low pressure chambers by the pressure guiding tube, under the action of the differential pressure p= p1-P2 >10, the bellows B1 in the high pressure chamber is compressed, and the volume decreases, and the inside The filled incompressible fluid will flow to the low-pressure chamber through the annular gap and the damping bypass, so that the bellows B2 will elongate and the volume will increase, thereby driving the connecting shaft to move from left to right. When the connecting shaft moves, it will drive the range spring to extend until the force formed by the differential pressure on the bottom surface of the bellows is balanced with the deformation force of the range spring and the bellows.
