[Abstract] Any valve with poor working performance in the pipe transportation system will lead to the decrease of the efficiency of the whole pipe transportation system. In an emergency, if the valve is locked and can not be closed, the fluid in the pipe will be continually released and lead to a sustained fire. If the valve is closed but the seal fails, it can also lead to a catastrophic accident that can lead to an explosion. It must be ensured that all valves will work as intended at all times.
[Key words] valve maintenance CLC number: TM734 Document code: A Article ID: 1009-914X (2017) 01-0087-01
Preface Valve Maintenance Prerequisites Various types of failures in piping valves can cause significant unsafe conditions in operation, so this must be eliminated with on-line valve maintenance. Maintenance should have the following conditions: First of all, before maintaining the valve to grasp the information about the pipeline and its characteristics, and find out the specific symptoms of the valve. Second, get the necessary permission.
First, the daily online valve maintenance Online valves can be repaired and the leak can be sealed, pipeline valve leaks can be economical, fast and easily eliminated. By taking safety precautions and following these proven steps, a sudden jet accident can be sourced from containment. One valve at a time, effective valve maintenance products will be a long time to ensure that the seal, which will extend the life of the valve maintenance months or even years.
(1) Moving Valve ①Moving Valve As part of routine maintenance, the benefits are: Moving valves will spread the sealant around the area of ​​the sealing surface. Inhibit valve rusting and possible stuck.
â‘¡ Activities Valve Conditions: Prior to the activation of any valve, obtain written approval from the supervisory staff and the pipeline maintenance and construction department. This is often referred to as a high-risk job permit because the valve is under pressure. Before moving the valve, stop injecting grease or valve cleaning fluid and depressurizing the grease gun. Make sure all blowdown / blowout nozzles are tightly closed. Also lubricate gear set bearings. Use a low pressure grease gun and inject a small amount of Sealweld through the nipple at different locations on the gear set Eterna-Lube 1000.
(2) Elimination of long-standing contaminants in the valve If the presence of oxygen and oxygen in the gas, the blow-off / blow-off nozzle or extension may freeze during high-pressure discharge. This can cause confusion because it looks as if the valve cavity has been completely relieved.
(3) Note Valve Lubricant or Sealant Do not turn valve when filling cleaning fluid or grease. Stop the pump and dispense the grease pressure before turning the valve.
(4) test the sealing performance of the valve seat:
Leak rate depends on the actual operating factors, in many cases less than 30CFM leakage rate is acceptable. A gas measuring device can be used to detect the leak rate. Record the leak rate before handling the leak.
(5) solution to the valve leakage â‘ recalibrate the valve switch â‘¡ injection of cleaning fluid, grease, may require the use of more and more dense sealing grease. WARNING: Actuate the valve at least 3 times after fresh grease or grease has been injected. Can not exceed injection pressure of 6000 PSI (414 Bar).
Second, regular comprehensive valve maintenance (1) a comprehensive valve maintenance work should be conducted once a year, even if the valve does not exist any leak or failure. Comprehensive valve maintenance is to prevent the occurrence of leakage or leakage of preventive measures to expand.
content include:
Clean valve seat seal system, seat seal system, re-grease (lubrication), valve cavity blowdown, adjust valve limit as required (if necessary), switch valve multiple times, increase stem seal pressure (if necessary) Rod, gearbox and all lubrication equipment to be tested Leakage of seat seal, leak detection of flange, injection port and stem (2) Sealing system Regular replenishment of sealant The amount of injection depends on factors before and after injection The time of grease interval, the type of grease / sealant used, the type of valve, the number of valve switch operations, the medium flowing through the valve, whether it is close to the metering or pressure regulating device (3) Preventive maintenance of new valves to maintain the correct design of the valve during the project design phase is very important in the valve technology must have the materials, accessories, test standards and other clear requirements. At the same time clear seal grease fittings, internal Check Valve , valve vent / drain connector size and type, the valve factory, transportation, on-site installation of the valve should be fully protected. At the same time before the valve is put into operation, the valve should be maintained.
Validity of the valve before the start of production Visual inspection All transport packaging complies with the requirements of the technical specifications; the interface is covered with anti-fouling and moisture wood cover; corrosion protection layer on the welding end and the flange end; No obvious damage, the valve body surface meets the technical specification requirements.
Before the valve is put into operation, it is used to maintain the hoisting ring which is marked by the hoisting supervision; when the hoisting chain is hoisted, the outer coating is taken protective measures; when the valve is provided with the bracket and the transmission mechanism, the hoisting rope is fixed on the hoisting ring of the valve instead of the transmission mechanism; Sling and hoisting chain can not hit the tube reached the height or the tube as a support.
Pre-valve maintenance Preservation of the valve installation welding operation of the valve installation work before welding to confirm the valve is in the "open" position; according to the needs of different brands and specifications of the valve, grease lubrication to protect the body and seal the pipeline; wipe Spread the inside of the Ball Valve to protect the grease, smear the grease between the seal ring and the ball body; Reinforce the valve port; Correct all threads; Confirm that all stems and grease fittings have no paint;
Valve welding protection operations; confirm the valve preheating and welding in the full "on" position;
The valve must be supported on its own base and is free to slide in the axial direction; when welding, the ball valve seal temperature does not exceed 140 ° C, the external injection port temperature does not exceed 80 ° C; lubricants added timely after the welding; Confirm that the various joints are not loose; confirm that the discharge port and discharge port are locked; turn the valve 1/2 "on" or "off" to confirm the operation is smooth; and after the welding is completed, pressure test to confirm the valve status is intact.
Third, the valve pressure test monitoring and protection of the sealing system 1, the pressure test scope of work ⑴ hydraulic test Before cleaning the pipeline pressure test to determine the valve in the "on" state; after the pipe is filled with water , Make sure the ball valve half-open at 10 ° -45 °; in the pipeline pressure, check whether all joints leak; pressure measurement after the implementation of sewage operations, clear the body pressure and impurities; valve back to all "on" state;
Add grease; supervise on-site personnel to operate the valve correctly; supervise the pressure test time to meet the technical requirements ⑵ pressure test phase before the pressure check the correct position of the valve; the valve fully open and foam test; the valve closed and foam test; valve back to normal Operating position; add lubricants; do stem leaking test. Pipeline pressure, the monitoring valve work, if leaks immediately repair;
a grease all the ball valves, b close all ball valves, c check the tightness of the valve, d fully open all ball valves, e re-drain, close the drain f, refill grease, and do a good job Trial run preparation (3) maintenance of the valve put into operation ①put into operation one quarter of a quarterly maintenance, ② second half a year after commissioning maintenance once, ③ put into operation two years after the annual maintenance, ④ annual pre-winter valve maintenance is In the production of an important part of operation, ⑤ valve operating conditions, frequency and other factors.
Fourth, valve maintenance tools Hand tools Use of materials and tools Checklist helps to understand the use of tools and storage conditions. Good access to tools records, but at any time to find the missing tools. Before going to work site, we must consider clearly what tools should be used to complete the site work. Taking into account the circumstances of an incident on site, determine the appropriate plan for dealing with the accident, including the selection of appropriate work tools. This is especially important for remote areas. Choosing the right work tool with the right tools should follow the manufacturer's specified or practical guidance. Wrenches slip easily, causing workers to get hurt or turning loose nuts. Use thread loose grease, then use small and stable torque to operate the wrench, with a small hammer to tighten the nut. If the fitting or part is difficult to unscrew, you must first secure it with a replacement wrench, preferably by loosening the moving part back and forth. Note: This problem may be the result of many years of accumulation, so may need to be processed several times in order to be finally resolved, be patient.
[Key words] valve maintenance CLC number: TM734 Document code: A Article ID: 1009-914X (2017) 01-0087-01
Preface Valve Maintenance Prerequisites Various types of failures in piping valves can cause significant unsafe conditions in operation, so this must be eliminated with on-line valve maintenance. Maintenance should have the following conditions: First of all, before maintaining the valve to grasp the information about the pipeline and its characteristics, and find out the specific symptoms of the valve. Second, get the necessary permission.
First, the daily online valve maintenance Online valves can be repaired and the leak can be sealed, pipeline valve leaks can be economical, fast and easily eliminated. By taking safety precautions and following these proven steps, a sudden jet accident can be sourced from containment. One valve at a time, effective valve maintenance products will be a long time to ensure that the seal, which will extend the life of the valve maintenance months or even years.
(1) Moving Valve ①Moving Valve As part of routine maintenance, the benefits are: Moving valves will spread the sealant around the area of ​​the sealing surface. Inhibit valve rusting and possible stuck.
â‘¡ Activities Valve Conditions: Prior to the activation of any valve, obtain written approval from the supervisory staff and the pipeline maintenance and construction department. This is often referred to as a high-risk job permit because the valve is under pressure. Before moving the valve, stop injecting grease or valve cleaning fluid and depressurizing the grease gun. Make sure all blowdown / blowout nozzles are tightly closed. Also lubricate gear set bearings. Use a low pressure grease gun and inject a small amount of Sealweld through the nipple at different locations on the gear set Eterna-Lube 1000.
(2) Elimination of long-standing contaminants in the valve If the presence of oxygen and oxygen in the gas, the blow-off / blow-off nozzle or extension may freeze during high-pressure discharge. This can cause confusion because it looks as if the valve cavity has been completely relieved.
(3) Note Valve Lubricant or Sealant Do not turn valve when filling cleaning fluid or grease. Stop the pump and dispense the grease pressure before turning the valve.
(4) test the sealing performance of the valve seat:
Leak rate depends on the actual operating factors, in many cases less than 30CFM leakage rate is acceptable. A gas measuring device can be used to detect the leak rate. Record the leak rate before handling the leak.
(5) solution to the valve leakage â‘ recalibrate the valve switch â‘¡ injection of cleaning fluid, grease, may require the use of more and more dense sealing grease. WARNING: Actuate the valve at least 3 times after fresh grease or grease has been injected. Can not exceed injection pressure of 6000 PSI (414 Bar).
Second, regular comprehensive valve maintenance (1) a comprehensive valve maintenance work should be conducted once a year, even if the valve does not exist any leak or failure. Comprehensive valve maintenance is to prevent the occurrence of leakage or leakage of preventive measures to expand.
content include:
Clean valve seat seal system, seat seal system, re-grease (lubrication), valve cavity blowdown, adjust valve limit as required (if necessary), switch valve multiple times, increase stem seal pressure (if necessary) Rod, gearbox and all lubrication equipment to be tested Leakage of seat seal, leak detection of flange, injection port and stem (2) Sealing system Regular replenishment of sealant The amount of injection depends on factors before and after injection The time of grease interval, the type of grease / sealant used, the type of valve, the number of valve switch operations, the medium flowing through the valve, whether it is close to the metering or pressure regulating device (3) Preventive maintenance of new valves to maintain the correct design of the valve during the project design phase is very important in the valve technology must have the materials, accessories, test standards and other clear requirements. At the same time clear seal grease fittings, internal Check Valve , valve vent / drain connector size and type, the valve factory, transportation, on-site installation of the valve should be fully protected. At the same time before the valve is put into operation, the valve should be maintained.
Validity of the valve before the start of production Visual inspection All transport packaging complies with the requirements of the technical specifications; the interface is covered with anti-fouling and moisture wood cover; corrosion protection layer on the welding end and the flange end; No obvious damage, the valve body surface meets the technical specification requirements.
Before the valve is put into operation, it is used to maintain the hoisting ring which is marked by the hoisting supervision; when the hoisting chain is hoisted, the outer coating is taken protective measures; when the valve is provided with the bracket and the transmission mechanism, the hoisting rope is fixed on the hoisting ring of the valve instead of the transmission mechanism; Sling and hoisting chain can not hit the tube reached the height or the tube as a support.
Pre-valve maintenance Preservation of the valve installation welding operation of the valve installation work before welding to confirm the valve is in the "open" position; according to the needs of different brands and specifications of the valve, grease lubrication to protect the body and seal the pipeline; wipe Spread the inside of the Ball Valve to protect the grease, smear the grease between the seal ring and the ball body; Reinforce the valve port; Correct all threads; Confirm that all stems and grease fittings have no paint;
Valve welding protection operations; confirm the valve preheating and welding in the full "on" position;
The valve must be supported on its own base and is free to slide in the axial direction; when welding, the ball valve seal temperature does not exceed 140 ° C, the external injection port temperature does not exceed 80 ° C; lubricants added timely after the welding; Confirm that the various joints are not loose; confirm that the discharge port and discharge port are locked; turn the valve 1/2 "on" or "off" to confirm the operation is smooth; and after the welding is completed, pressure test to confirm the valve status is intact.
Third, the valve pressure test monitoring and protection of the sealing system 1, the pressure test scope of work ⑴ hydraulic test Before cleaning the pipeline pressure test to determine the valve in the "on" state; after the pipe is filled with water , Make sure the ball valve half-open at 10 ° -45 °; in the pipeline pressure, check whether all joints leak; pressure measurement after the implementation of sewage operations, clear the body pressure and impurities; valve back to all "on" state;
Add grease; supervise on-site personnel to operate the valve correctly; supervise the pressure test time to meet the technical requirements ⑵ pressure test phase before the pressure check the correct position of the valve; the valve fully open and foam test; the valve closed and foam test; valve back to normal Operating position; add lubricants; do stem leaking test. Pipeline pressure, the monitoring valve work, if leaks immediately repair;
a grease all the ball valves, b close all ball valves, c check the tightness of the valve, d fully open all ball valves, e re-drain, close the drain f, refill grease, and do a good job Trial run preparation (3) maintenance of the valve put into operation ①put into operation one quarter of a quarterly maintenance, ② second half a year after commissioning maintenance once, ③ put into operation two years after the annual maintenance, ④ annual pre-winter valve maintenance is In the production of an important part of operation, ⑤ valve operating conditions, frequency and other factors.
Fourth, valve maintenance tools Hand tools Use of materials and tools Checklist helps to understand the use of tools and storage conditions. Good access to tools records, but at any time to find the missing tools. Before going to work site, we must consider clearly what tools should be used to complete the site work. Taking into account the circumstances of an incident on site, determine the appropriate plan for dealing with the accident, including the selection of appropriate work tools. This is especially important for remote areas. Choosing the right work tool with the right tools should follow the manufacturer's specified or practical guidance. Wrenches slip easily, causing workers to get hurt or turning loose nuts. Use thread loose grease, then use small and stable torque to operate the wrench, with a small hammer to tighten the nut. If the fitting or part is difficult to unscrew, you must first secure it with a replacement wrench, preferably by loosening the moving part back and forth. Note: This problem may be the result of many years of accumulation, so may need to be processed several times in order to be finally resolved, be patient.
Wuzhong Instrument Co., Ltd. , https://www.wzivalve.com