5. Operation and use
1) Before operation, confirm that pipelines and valves have been flushed.
2) The operation of the valve drives the valve rod to rotate according to the input signal of the actuator: when the valve rotates 1/4 circle (90 °) in the positive direction, the valve is closed. When the valve rotates 1/4 turn (90 °) in the opposite direction, the valve opens
3) When the direction indicating arrow of the actuator is parallel to the pipeline, the valve is open; When the arrow is perpendicular to the pipeline, the valve is closed
6. Maintenance has a long service life and maintenance free period, which will depend on the following factors: normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data.

Preparation before overhaul of tetrafluoro compensator Understand its performance characteristics
Preparation before maintenance of engineering pipeline compensator
1) Prepare all drawings and technical materials, and prepare the construction plan if necessary.
2) Check the quality certificate of the pipeline data and stop the appearance inspection. See Appendix A for selection of common steel pipes.
3) Block the equipment or system for asynchronous maintenance, and add blind plates. The internal purging and replacement of the pipeline are clean, and the construction site conforms to the relevant safety rules.
Dismantling of used pipeline compensator
1) When the operating temperature of the pipeline is higher than 250 ℃ and the temperature drops to 150 ℃, the bolts to be removed shall be poured with mechanical oil or rust inhibitor.
2) The disassembled high-pressure bolts, nuts and reusable gaskets shall be cleaned and inspected one by one.
3) The sealing surface of each part shall be maintained during disassembly, and the open flange of the tetrafluoroethylene compensator shall be sealed for maintenance.
4) The removed pipeline shall be well supported to prevent falling and deformation.
5) For austenitic stainless steel pipes that are likely to suffer from corrosion cracking caused by polysulfuric acid, neutralization cleaning or nitrogen maintenance should be stopped before contacting the atmosphere after disassembly. The recommended neutralization cleaning plan refers to NACE RP0170-97 Protection of Austenitic Stainless Steel and Other Austenitic Alloy Refinery Equipment from Stress Corrosion Cracking Caused by Polysulfuric Acid During Shutdown.