Some common malfunctions and solutions for electric contact pressure gauges

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### Malfunctions Related to the Pointer - **The pointer does not point to the zero position**:

- **The Bourdon tube loses its elasticity**: If the Bourdon tube becomes straightened, it will cause the pointer to fail to indicate the zero position normally. At this time, the Bourdon tube or the entire pressure gauge needs to be replaced.

- **The hairspring loses its elasticity or falls off**: Problems with the hairspring may also cause the pointer to deviate from the zero position. The hairspring should be replaced and ensure that it is installed correctly.

- **The three-way cock, the connecting pipe of the pressure gauge or the water seal bend is blocked**: Blockage of the channels will affect the pressure transmission and cause abnormal indication of the pointer. It is necessary to clean the blockages to ensure the channels are unobstructed.

- **The pointer is bent or stuck**: If the pointer itself is bent or stuck with other components, it will be unable to rotate to the zero position normally. It is necessary to straighten or replace the pointer and check the clearance between it and the surrounding components.

- **The pointer shakes**:

- **The hairspring is damaged**: Damage to the hairspring will cause the pointer to lose its balance and shake. The hairspring should be replaced in a timely manner.

- **The connecting bolt of the connecting rod and the sector gear is immovable**: If the bolt is immovable, it will lead to poor transmission and cause the pointer to shake. It is necessary to disassemble, inspect and clean it to ensure that the bolt can move freely. Replace the bolt if necessary.

- **Both ends of the central shaft are bent**: Bending of the central shaft will cause the rotation to be eccentric and trigger the pointer to shake. It is necessary to straighten or replace the central shaft.

- **The channels of the three-way cock or the water seal bend of the pressure gauge are partially blocked or covered by linings**: Clean the blockages or coverings to ensure smooth channels.

- **The pointer does not move**:

- **The three-way cock is not opened or its position is incorrect**: Check and ensure that the three-way cock is opened and in the correct position.

- **The channels of the three-way cock, the pressure gauge or the water seal bend are blocked**: Clean the blockages in each channel.

- **The joint between the pointer and the central shaft is loose or the pointer is stuck**: Tighten the joint between the pointer and the central shaft. If the pointer is damaged, it needs to be replaced. Clean the foreign objects that are stuck to the pointer or adjust the clearance between the pointer and the surrounding components.

- **The welding joint between the Bourdon tube and the gauge base leaks**: Repair the leakage by welding or replace the Bourdon tube.

- **The shaft of the sector gear is loose or disengaged and cannot transmit power to the pinion**:

Check and tighten the shaft of the sector gear to ensure normal transmission.

Malfunctions Related to Signals

- **The electric contact device does not send signals**:

- **The contacts are too dirty and have poor contact**: Polish the contacts with sandpaper to remove dirt and ensure good contact.

- **The insulating layer of the signal device gets damp**: Use a hot air blower to dry the insulating layer and remove the moisture.

- **The circuit is open**: Locate the open circuit position and repair it. For example, if the connection is loose, tighten it. If the wire is damaged, replace it.

- **The electric contact pressure gauge sends signals too early or too late**:

- **The position of the contacts is incorrect**: Correct the position of the contacts to make them perpendicular to the early warning end and ensure that the signals are triggered at the accurate pressure value.

- **The metal rod of the contacts is loose**: Reinforce the metal rod of the contacts. If the looseness is relatively slight, the hairspring can be appropriately enlarged to increase the reaction torque of the hairspring.

Malfunctions Related to Appearance and Display

- **The surface of the pressure gauge is blurry or has water droplets**:

- **The Bourdon tube of the pressure gauge leaks**: Locate the leakage point and repair it. For example, if the welding is poor, re-weld it. If the damage is serious, replace the Bourdon tube.

- **The sealing surface between the gauge case and the glass plate is not good**: Check and replace the rubber gasket to ensure good sealing between the gauge case and the glass plate.

- **The glass of the pressure gauge is broken**:

- **Packaging or transportation problems**: For example, if there is too much space in the packaging box for the instrument or the packaging box is dropped, etc. It is necessary to improve the packaging and transportation methods and strengthen the protective measures.

- **The end face of the gauge case is not flat**: When installing the cover, ensure that the end face of the gauge case is flat to avoid excessive force that may cause stress cracks in the glass.