The pressure gauge with electrical contact is composed of a measuring system, an indicating system, a magnetic-assisted electric contact device, a casing, an adjustment device, and a junction box (plug seat). General electrical contact pressure gauges are used to measure the positive and negative pressures of gas and liquid media that are not corrosive to copper and copper alloys. Electrical contact pressure gauges are widely used in petroleum, chemical, metallurgy, power stations, machinery and other industrial sectors or mechanical and electrical equipment to measure the pressure of various fluid media without explosion hazard. Generally, the contact pressure gauge is used in conjunction with the corresponding electrical devices (such as relays and inverters, etc.) to automatically control and send signals (alarms) through the meter for various gas and liquid media whose pressure is measured (controlled).
The electrical contact signal pin of the electrical contact pressure gauge device is equipped with an adjustable permanent magnet, which can increase the suction force of the contact and accelerate the contact action, so that the contact is reliable, the arc can be eliminated, and it can effectively avoid the frequent shutdown of the contacts of the instrument due to the vibration of the working environment or the pressure pulsation of the medium. Therefore, the electric contact pressure gauges have the advantages of reliable action, long service life, and large contact switch power. The instrument also has the advantages of combined measurement and control, simple installation, and small maintenance.
1. The electric contact pressure gauge is actually a circuit switch operated by the pressure gauge.
It is only an electric contact signal device added to the ordinary pressure gauge. Therefore, the verification of the pressure part is the same as that of the ordinary pressure gauge, except that the pressure part is qualified. Only after the pressure part has passed the verification, the verification of the electric contact signal device needs to be added.
2. Verification steps of electric contact pressure gauges
Install the pressure gauge on the calibrator, use the needle selector to set the two signal contact pointers outside the upper and lower limits respectively, and then perform the value verification. After the indicating value verification is qualified, set the upper and lower signal contact pointers at three or more different verification points respectively, slowly increase or decrease the pressure until the signal is sent. Then the deviation between the reading of the standard pressure gauge and the indicated value of the signal pointer shall not exceed the absolute value of the allowable basic error.
The electric contact pressure gauge is based on the spring tube in the measuring system under the pressure of the measured medium, forcing the end of the spring tube to produce corresponding elastic deformation and displacement. This kind of electrical contact pressure gauge is driven by the gear transmission mechanism with the help of the pull rod and amplified. The indication (together with the contact) will indicate the measured value on the dial one by one. At the same time, when it is in touch with the contact (upper or lower limit) on the setting pointer (moving off or on), the circuit in the control system can be disconnected or connected to achieve automatic control and transmission, in order to achieve the purpose of automatic control and sending an alarm.