Preventive maintenance of control valve

There are two kinds of regulating valve repair: One is preventive maintenance, The main means in order to ensure the reliable operation of the regulating valve, And in the event of a failure to take the preventive and repair measures, including in the field of control valve when the installation and use of a series of preventive measures taken; The other is fault maintenance, That is, when the control valve can not meet the requirements of the operation under fault conditions a series of maintenance work, Normally at the completion of the workshop, special circumstances may also direct maintenance on the pipeline.

Preventive Maintenance

Preventive maintenance is the regulator of the planned maintenance before the failure occurs, can be understood as the day-to-day maintenance, usually including the following work.

1. The elimination of stress

Due to the combination of pipeline or improper installation can produce all kinds of stress, For example, the thermal stress of high temperature medium, the stress caused by uneven fastening force installation, artificial some of the stress caused by the collision to the regulating valve and pipe and so on.These stress on the role of regulating valve and the pipeline, It is easy to have an impact on the performance of the control valve, which will affect the regulation of the system itself, resulting in the deformation of the valve rod and the guide can't seat at the Centre; For the split-body valve, may be caused by the disconnection of the flange of the valve body; Stress may cause the valve seat leakage and so on.Therefore, at any time make sure to avoid or eliminate the stress, stress oriented away from the local regulator.

2. The inspection of the safety operation

On the regulating valve used in explosion hazardous areas and the related annex should be examined for its safe operation, For example, seal cap is airtight, the operation of the security gate, power supply and so on, to ensure the safe operation of the control valve and the relevant annexes to.

3 Check-up condition

Install the regulator with the best position to make the top of the direction of travel of the valve stem and valve body of the executive body in a vertical plane.If the valve must be installed in a horizontal movement of the valve stem position, Or the moving direction of the valve rod and the horizontal plane when a certain angle, they'd take the support of the implementing agencies, and to make the various parts of the control valve in the state of nature.If you do not add support or support additional misconduct may be caused by different heart valve stem and valve seat, easy to cause the differential or packing such as leakage fault.Even if the valve is available in fixed and support measures to check must also be conducted on a regular basis, usually 2 ~ 3 months.

4 The removal or prevent the entry of foreign matter

Always check the presence or absence of rust control valve connecting pipe, welding slag, sewage, etc., Should be cleared after the discovery.If the control valve and the pipeline is easy to accumulate foreign, will be taken into account in the side of the shutoff valve upstream of the installation of a simple filtration devices.In the process of occasions in the medium which can seep into the hard stuff, be sure to install a permanent filter.Because the control valve is closed, A very small piece of rust or welding slag is enough to damage the sealing surface of the valve seat grinding Well, Moreover, the dirt will be caused by valve core and valve seat wear, affect its normal operation.

5 Periodic maintenance and refuelling

After packing and oiler in the short-term use needs to be recalibrated.The dust number of occasions to the valve stem stuffing around the plastic or rubber sleeve to protect and guide the location, The presence of corrosive gas or liquid droplets occasion to adopt special protective measures for general use antiseptic bags of control valve, but should take care not to affect its operation.In the fire resistance requirements of the occasion, special fire-resistant coating can be used, set fire-proof bag and other methods, the material fire-proof bag containing multi-layer ceramic fiber or fiberglass.

6 Transportation and storage

Control Valve in Assembly and paint and the implementing agencies are required to be installed, Hand-wheels, annex, the positioner, etc. In order to prevent foreign matter entering the valve, All the air interface to plug the connection control valve, Connecting flange mounted on the cover, to pay attention to the various connection parts, such as intake manifold valve positioner, the state of the interface of the implementing agencies.Easy to damage any outstanding attachments, such as oil and a potentiometer pressure gauge should be removed from the joints, and regulating the transport of packed separately and together.Control valve application-specific fixation, loosening can be prevented to ensure that the overall vertical or horizontal position.If the long-range transport, it is best to use strong wooden cases.

Custody when the control valve, don't put the valve is supported on the sensitive parts, such as valve positioner, the stem and so on.The conditions of carriage, and preservation of the environment should meet the requirements of the specifications.The custody of the region's best not to conduct other operations, these cannot be avoided, must be careful not to touch the valve.Places would also like to avoid the wind, The dust, the impact of the harsh conditions such as rain, if there is no appropriate place, the valve must be put before storage in a moisture-proof bag or similar container.

7 Periodic inspection of gas source and power source

The gas source is one of the key energy to drive the control valve.Although it is not the consumption of the pneumatic control valve compartment air, But if the gas source system contains water, oil and other impurities, it will make the valve positioner, relay accessories such as congestion and failure.Therefore, the importance of regular check on the source of the gas and power, to ensure that the gas source of clean, dry and reliable power supply.