Causes and calibration of pressure gauge errors
The two errors of the pressure gauge refer to: one is that the pressure gauge being checked always increases or decreases by a fixed value; the other is that the error of the pressure gauge being checked increases or decreases proportionally.
The reason that the error of the tested pressure gauge always increases or decreases by a fixed value is the system error caused by the incorrectly installed pointer of the bellows pressure gauge. It is easy to adjust this error. Just start the needle again and adjust the pointer installation position. Can eliminate errors. Magnetic flap level gauge.
The error of the tested pressure gauge increases or decreases proportionally, which is mainly caused by a change in the transmission ratio. Just move the indicating adjustment screw to solve it. When the error of the tested pressure gauge gradually increases, move the indicating value adjustment screw to the right, enlarge the arm length of the short arm of the sector gear, and lower the transmission ratio. When the error of the tested pressure gauge gradually decreases, the indicating value adjustment screw should be moved to the left, the arm length of the short arm of the sector gear should be reduced, and the transmission ratio should be increased.
How to check the error of the pressure gauge? First of all, there are three kinds of pressure gauge errors: 1. Fixed error 2. Linear error 3. Non-linear error
1. Fixed error: In the entire range, the reading of the tested meter is different from the standard meter value by a certain fixed value. Re-start the needle of the shock-resistant pressure gauge and adjust the installation position.
2. Linear error: In the entire range, the difference between the reading of the tested meter and the standard indicated value increases or decreases proportionally. The reason for the error is that the transmission ratio of the instrument has changed. The error of the bellows pressure gauge increases proportionally. The screw between the sector gear and the connecting rod is moved (right) outward to reduce the transmission ratio, and vice versa. , Then move to (left) inward and repeat adjustments.
3. Non-linear error: the instrument error increases or decreases with the pressure, from a positive value to a negative value, the shock-resistant pressure gauge or from a negative value to a positive value. The reason is due to The turning angle of the pointer in the stroke is greater than or less than 270 degrees to adjust the movement.
