Valves Maintenance Manual
The maintenance and management of the valve include the whole process of picking up and handling, storage and installation, which is an important guarantee measure for the normal operation of the valve.
1. Valve maintenance in transit
The valve handwheel is damaged, the valve stem is bent, the bracket is broken, and the flange sealing surface is damaged by bumping, especially the damage of gray cast iron valve, a considerable part of which occurs during the transportation of the valve. The causes of the above damages are mainly caused by the transport personnel's ignorance of the basic knowledge of valves and brutal loading and unloading operations.
Before transporting the valve, ropes, lifting equipment and transportation tools should be prepared. Check the packaging of the valve. If the packaging is damaged, it should be fixed properly, without being afraid of trouble or luck. Packaging should meet the standard requirements, and it is not allowed to rotate the handwheel of packaged and sealed valves casually; The valve should be in a fully closed state. For valves that have been opened by mistake, the sealing surface should be wiped clean before closing tightly, and the inlet and outlet passages should be closed. The transmission device shall be packaged and transported separately from the valve.
When lifting the valve during shipment, the rope should be tied to the flange or bracket, and should not be tied to the handwheel or valve stem. The valve should be lifted and put down gently, without hitting other objects, and placed stably. The placing posture should be upright or inclined, and the valve stem should be upward. For valves that are not placed safely, they should be tied with ropes or fixed firmly with cushion blocks, so as not to collide with each other during transportation.
When loading and unloading the valve manually, it is not allowed to throw the valve down from the vehicle or from the ground to the vehicle. In the process of handling, it should be orderly and arranged in sequence, and stacking is strictly prohibited.
During the transportation of the valve, take good care of the paint, nameplate and flange sealing surface. It is not allowed to drag the valve on the ground, and it is not allowed to move the valve inlet and outlet sealing surfaces to the ground.
Do not unpack the valves that are not installed at the construction site, but place them in a safe place, and do a good job of preventing rain and dust.
2. The valve maintenance in custody
After the valve is transported into the warehouse, the keeper shall go through the warehousing formalities in time, which is beneficial to the inspection and storage of the valve. The keeper should carefully check the model and specification of the valve, check the appearance quality of the valve, and assist the inspectors to carry out the strength test and sealing test of the valve before warehousing. Valves that meet the acceptance criteria can go through warehousing formalities; Unqualified products shall also be properly kept and treated by relevant departments.
For the valves in storage, carefully wipe and clean the accumulated water, dust and dirt of the valves during transportation; The machined surface, valve stem and sealing surface which are easy to rust should be coated with a layer of the antirust agent or pasted with a layer of antirust paper for protection. The inlet and outlet passages of valves should be closed with plastic covers or wax paper to avoid dirt from entering.
The valves in stock should be consistent with the accounts, classified, placed neatly, clearly labeled and easily recognized. Small valves shall be discharged on the shelves according to the model specification and size sequence; Large valves can be discharged on the warehouse floor and placed in blocks according to the model and specifications. Valves should be placed upright or obliquely, and the sealing surfaces of flanges should not touch the ground, let alone be stacked together. For extra-large valves and valves that cannot be put into storage temporarily, they should also be placed upright in outdoor dry and ventilated places according to their categories and sizes; The valve sealing surface should be protected by oil, and the passage should be sealed. If there is no filler in the stuffing box, in order to prevent rainwater from entering the valve, the stuffing box should be sealed with grease such as butter, and covered with items such as felt or poncho. It is best to build a temporary warehouse shed for protection.
In order to keep the valves in good condition, besides a dry, ventilated, clean and dust-free warehouse, a set of advanced and scientific management systems should be provided. All valves in custody shall be maintained and inspected regularly. Generally, from the date of delivery, a pressure test shall be conducted again 18 months later.
For long-term unused valves, if asbestos packing is used, the asbestos packing should be taken out of the packing box to avoid electrochemical corrosion and damage to the valve stem. For valves without packing, the manufacturer is generally equipped with spare packing, and the keeper should keep it properly.
The valve parts damaged or lost during handling, such as handwheel, handle and scale shall be fully equipped in time, and shall not be missing.
Rust inhibitors and lubricants that exceed the specified service life shall be replaced or added regularly as required.
3. The valve maintenance in operation
The purpose of valve maintenance in operation is to ensure that the valve is in a state of clean, well-lubricated, complete valves and normal operation all year-round.
3.1. Cleaning of valves
The valve surface, trapezoidal thread on the valve stem and valve stem nut, sliding parts between the valve stem nut and bracket, gears, worm gears and other parts are prone to be stained with many dirt such as dust, oil stains and residual stains of the medium, which will cause wear and corrosion to the valve. Therefore, it is obviously very important to keep the exterior and moving parts of the valve clean and protect the integrity of the valve paint. Dust on the valve is suitable for brush brushing and compressed air purging; Dirt between trapezoidal thread and teeth is suitable for scrubbing with a dishcloth. An oil stain and residual medium stain on the valve are suitable for steam purging, even brushing with a copper wire brush, until the machined surface and mating surface show metallic luster, and the painted surface shows paint color. The trap should be checked at least once per shift, and the plug at the bottom of the flush valve and trap should be opened regularly for flushing, or the trap should be disassembled and flushed regularly, so as to avoid dirt blocking the valve.
3.2 Lubrication of the valve
The sliding parts of valve trapezoidal thread, valve stem nut and bracket, bearing parts, meshing parts of gears, worm gears and other cooperating moving parts all need good lubrication conditions to reduce mutual friction and avoid mutual wear. Some parts are specially equipped with oil cups or nozzles. If they are damaged or lost during the operation, they should be repaired and equipped, and the oil passages should be dredged.
Lubrication parts shall be oiled regularly according to specific conditions. Frequently opened and high-temperature valves are suitable for refueling once every week to once every month; The refueling cycle of valves that are not frequently opened and have low temperature can be longer. Lubricants include engine oil, butter, molybdenum disulfide and graphite. High-temperature valves are not suitable for engine oil and butter, which will be lost due to melting at high temperatures, so they are suitable for injecting molybdenum disulfide and wiping graphite powder. For exposed parts needing lubrication, such as trapezoidal threads and gears, if grease such as butter is used, it is easy to get dust, while molybdenum disulfide and graphite powder are used for lubrication, it is not easy to get dust, and the lubrication effect is better than butter. Graphite powder is not easy to apply directly, so it can be blended into a paste with a little engine oil or water.
The sealed plug valve should be filled with oil according to the specified time, otherwise, it is easy to wear and leak.
3.3 Maintenance of valves
The valves in operation and various valve parts shall be complete and in good condition. And the bolts on the flange and bracket are indispensable, and the threads should be intact without looseness. The fastening nuts on the handwheel should be tightened in time in case of looseness, so as to avoid wearing the joint or losing the handwheel and nameplate. If the handwheel is lost, it is not allowed to replace it with a spanner, and it should be completed in time. The packing gland is not allowed to skew or have no pre-tightening clearance. For valves that are easily contaminated by rain, snow, dust, sand and other dirt, the valve stem should be installed with a protective cover. The scale on the valve shall be kept complete, accurate and clear. The valve seal, cap and pneumatic accessories shall be complete and intact. The insulation jacket shall be free of depressions and cracks. It is not allowed to knock, stand or support heavy objects on the running valve; Especially non-metallic valves and cast iron valves.
4. Maintenance of Idle Valves
Maintenance of idle valves shall be carried out together with equipment and pipelines, and the following work shall be done:
(1) Clean the valve
The inner cavity of the valve should be purged and cleaned, free of residues and aqueous solution, and the outer part of the valve should be wiped clean, free of dirt, oil.
(2) Complete valve parts
After the valve is missing, it cannot be removed from the east and replaced by the west, and the valve parts should be fully equipped to create favorable conditions for the next use and ensure that the valve is finished.
(3)Anticorrosion treatment
Take out the packing in the stuffing box to prevent electrochemical corrosion of the valve stem, and apply antirust agent and grease to the valve sealing surface, valve stem, valve stem nut, machined surface and other parts according to specific conditions; Paint parts should be painted with antirust paint.
(4) Protection and protection.
To prevent the impact of other objects, manual handling and disassembly. If necessary, fix the movable parts of the valve and package and protect the valve.
4. Regular maintenance
Valves that have been idle for a long time should be inspected and maintained regularly to prevent corrosion and damage to the valves. For valves that have been idle for too long, they can only be used after they have passed the pressure test together with equipment, devices and pipelines.
5. maintenance of electric devices
The daily maintenance of the electric device is generally not less than once a month. Maintenance contents include: clean appearance and no dust accumulation; The device is not contaminated by steam, water and oil. The electric device shall be well sealed, and all sealing surfaces and points shall be complete, firm, tight and free of leakage. The electric device shall be well lubricated and oiled on time and in accordance with regulations, and the valve stem nut shall be greased. Electrical parts should be in good condition, avoid moisture and dust erosion; In case of damp, the insulation resistance between all current-carrying parts and the shell shall be measured with a 500V megohmmeter, and the value shall not be lower than 0.38mohm, otherwise, the relevant parts shall be dried. Automatic switch and thermal relay shall not be tripped, and the indicator light shall be displayed correctly, without any phase, short circuit or open circuit faults. The working state of the electric device is normal, with flexible opening and closing.
6. Maintenance of Pneumatic Devices
The daily maintenance of pneumatic devices is generally not less than once a month. The main contents of maintenance are a clean appearance and no dust accumulation; The device shall not be contaminated by water vapor, water and oil pollution. The sealing of the pneumatic device shall be good, and all sealing surfaces and points shall be complete and firm and shall be tight and undamaged. The manual operating mechanism should be well lubricated and open and close flexibly. No damage is allowed to the inlet and outlet gas joints of the cylinder; Each part of the cylinder and air piping system shall be carefully inspected, and there shall be no leakage affecting the service performance. No-sag is allowed in the pipe, the annunciator should be in good condition, the indicator light of the annunciator should be in good condition, and the connecting threads of both pneumatic annunciator and electric annunciator should be in good condition without leakage. The valves on pneumatic devices shall be intact, free from leakage, flexible to open and smooth in airflow. The whole pneumatic device should be in normal working condition with a flexible opening and closing.
1. Valve maintenance in transit
The valve handwheel is damaged, the valve stem is bent, the bracket is broken, and the flange sealing surface is damaged by bumping, especially the damage of gray cast iron valve, a considerable part of which occurs during the transportation of the valve. The causes of the above damages are mainly caused by the transport personnel's ignorance of the basic knowledge of valves and brutal loading and unloading operations.
Before transporting the valve, ropes, lifting equipment and transportation tools should be prepared. Check the packaging of the valve. If the packaging is damaged, it should be fixed properly, without being afraid of trouble or luck. Packaging should meet the standard requirements, and it is not allowed to rotate the handwheel of packaged and sealed valves casually; The valve should be in a fully closed state. For valves that have been opened by mistake, the sealing surface should be wiped clean before closing tightly, and the inlet and outlet passages should be closed. The transmission device shall be packaged and transported separately from the valve.
When lifting the valve during shipment, the rope should be tied to the flange or bracket, and should not be tied to the handwheel or valve stem. The valve should be lifted and put down gently, without hitting other objects, and placed stably. The placing posture should be upright or inclined, and the valve stem should be upward. For valves that are not placed safely, they should be tied with ropes or fixed firmly with cushion blocks, so as not to collide with each other during transportation.
When loading and unloading the valve manually, it is not allowed to throw the valve down from the vehicle or from the ground to the vehicle. In the process of handling, it should be orderly and arranged in sequence, and stacking is strictly prohibited.
During the transportation of the valve, take good care of the paint, nameplate and flange sealing surface. It is not allowed to drag the valve on the ground, and it is not allowed to move the valve inlet and outlet sealing surfaces to the ground.
Do not unpack the valves that are not installed at the construction site, but place them in a safe place, and do a good job of preventing rain and dust.
2. The valve maintenance in custody
After the valve is transported into the warehouse, the keeper shall go through the warehousing formalities in time, which is beneficial to the inspection and storage of the valve. The keeper should carefully check the model and specification of the valve, check the appearance quality of the valve, and assist the inspectors to carry out the strength test and sealing test of the valve before warehousing. Valves that meet the acceptance criteria can go through warehousing formalities; Unqualified products shall also be properly kept and treated by relevant departments.
For the valves in storage, carefully wipe and clean the accumulated water, dust and dirt of the valves during transportation; The machined surface, valve stem and sealing surface which are easy to rust should be coated with a layer of the antirust agent or pasted with a layer of antirust paper for protection. The inlet and outlet passages of valves should be closed with plastic covers or wax paper to avoid dirt from entering.
The valves in stock should be consistent with the accounts, classified, placed neatly, clearly labeled and easily recognized. Small valves shall be discharged on the shelves according to the model specification and size sequence; Large valves can be discharged on the warehouse floor and placed in blocks according to the model and specifications. Valves should be placed upright or obliquely, and the sealing surfaces of flanges should not touch the ground, let alone be stacked together. For extra-large valves and valves that cannot be put into storage temporarily, they should also be placed upright in outdoor dry and ventilated places according to their categories and sizes; The valve sealing surface should be protected by oil, and the passage should be sealed. If there is no filler in the stuffing box, in order to prevent rainwater from entering the valve, the stuffing box should be sealed with grease such as butter, and covered with items such as felt or poncho. It is best to build a temporary warehouse shed for protection.
In order to keep the valves in good condition, besides a dry, ventilated, clean and dust-free warehouse, a set of advanced and scientific management systems should be provided. All valves in custody shall be maintained and inspected regularly. Generally, from the date of delivery, a pressure test shall be conducted again 18 months later.
For long-term unused valves, if asbestos packing is used, the asbestos packing should be taken out of the packing box to avoid electrochemical corrosion and damage to the valve stem. For valves without packing, the manufacturer is generally equipped with spare packing, and the keeper should keep it properly.
The valve parts damaged or lost during handling, such as handwheel, handle and scale shall be fully equipped in time, and shall not be missing.
Rust inhibitors and lubricants that exceed the specified service life shall be replaced or added regularly as required.
3. The valve maintenance in operation
The purpose of valve maintenance in operation is to ensure that the valve is in a state of clean, well-lubricated, complete valves and normal operation all year-round.
3.1. Cleaning of valves
The valve surface, trapezoidal thread on the valve stem and valve stem nut, sliding parts between the valve stem nut and bracket, gears, worm gears and other parts are prone to be stained with many dirt such as dust, oil stains and residual stains of the medium, which will cause wear and corrosion to the valve. Therefore, it is obviously very important to keep the exterior and moving parts of the valve clean and protect the integrity of the valve paint. Dust on the valve is suitable for brush brushing and compressed air purging; Dirt between trapezoidal thread and teeth is suitable for scrubbing with a dishcloth. An oil stain and residual medium stain on the valve are suitable for steam purging, even brushing with a copper wire brush, until the machined surface and mating surface show metallic luster, and the painted surface shows paint color. The trap should be checked at least once per shift, and the plug at the bottom of the flush valve and trap should be opened regularly for flushing, or the trap should be disassembled and flushed regularly, so as to avoid dirt blocking the valve.
3.2 Lubrication of the valve
The sliding parts of valve trapezoidal thread, valve stem nut and bracket, bearing parts, meshing parts of gears, worm gears and other cooperating moving parts all need good lubrication conditions to reduce mutual friction and avoid mutual wear. Some parts are specially equipped with oil cups or nozzles. If they are damaged or lost during the operation, they should be repaired and equipped, and the oil passages should be dredged.
Lubrication parts shall be oiled regularly according to specific conditions. Frequently opened and high-temperature valves are suitable for refueling once every week to once every month; The refueling cycle of valves that are not frequently opened and have low temperature can be longer. Lubricants include engine oil, butter, molybdenum disulfide and graphite. High-temperature valves are not suitable for engine oil and butter, which will be lost due to melting at high temperatures, so they are suitable for injecting molybdenum disulfide and wiping graphite powder. For exposed parts needing lubrication, such as trapezoidal threads and gears, if grease such as butter is used, it is easy to get dust, while molybdenum disulfide and graphite powder are used for lubrication, it is not easy to get dust, and the lubrication effect is better than butter. Graphite powder is not easy to apply directly, so it can be blended into a paste with a little engine oil or water.
The sealed plug valve should be filled with oil according to the specified time, otherwise, it is easy to wear and leak.
3.3 Maintenance of valves
The valves in operation and various valve parts shall be complete and in good condition. And the bolts on the flange and bracket are indispensable, and the threads should be intact without looseness. The fastening nuts on the handwheel should be tightened in time in case of looseness, so as to avoid wearing the joint or losing the handwheel and nameplate. If the handwheel is lost, it is not allowed to replace it with a spanner, and it should be completed in time. The packing gland is not allowed to skew or have no pre-tightening clearance. For valves that are easily contaminated by rain, snow, dust, sand and other dirt, the valve stem should be installed with a protective cover. The scale on the valve shall be kept complete, accurate and clear. The valve seal, cap and pneumatic accessories shall be complete and intact. The insulation jacket shall be free of depressions and cracks. It is not allowed to knock, stand or support heavy objects on the running valve; Especially non-metallic valves and cast iron valves.
4. Maintenance of Idle Valves
Maintenance of idle valves shall be carried out together with equipment and pipelines, and the following work shall be done:
(1) Clean the valve
The inner cavity of the valve should be purged and cleaned, free of residues and aqueous solution, and the outer part of the valve should be wiped clean, free of dirt, oil.
(2) Complete valve parts
After the valve is missing, it cannot be removed from the east and replaced by the west, and the valve parts should be fully equipped to create favorable conditions for the next use and ensure that the valve is finished.
(3)Anticorrosion treatment
Take out the packing in the stuffing box to prevent electrochemical corrosion of the valve stem, and apply antirust agent and grease to the valve sealing surface, valve stem, valve stem nut, machined surface and other parts according to specific conditions; Paint parts should be painted with antirust paint.
(4) Protection and protection.
To prevent the impact of other objects, manual handling and disassembly. If necessary, fix the movable parts of the valve and package and protect the valve.
4. Regular maintenance
Valves that have been idle for a long time should be inspected and maintained regularly to prevent corrosion and damage to the valves. For valves that have been idle for too long, they can only be used after they have passed the pressure test together with equipment, devices and pipelines.
5. maintenance of electric devices
The daily maintenance of the electric device is generally not less than once a month. Maintenance contents include: clean appearance and no dust accumulation; The device is not contaminated by steam, water and oil. The electric device shall be well sealed, and all sealing surfaces and points shall be complete, firm, tight and free of leakage. The electric device shall be well lubricated and oiled on time and in accordance with regulations, and the valve stem nut shall be greased. Electrical parts should be in good condition, avoid moisture and dust erosion; In case of damp, the insulation resistance between all current-carrying parts and the shell shall be measured with a 500V megohmmeter, and the value shall not be lower than 0.38mohm, otherwise, the relevant parts shall be dried. Automatic switch and thermal relay shall not be tripped, and the indicator light shall be displayed correctly, without any phase, short circuit or open circuit faults. The working state of the electric device is normal, with flexible opening and closing.
6. Maintenance of Pneumatic Devices
The daily maintenance of pneumatic devices is generally not less than once a month. The main contents of maintenance are a clean appearance and no dust accumulation; The device shall not be contaminated by water vapor, water and oil pollution. The sealing of the pneumatic device shall be good, and all sealing surfaces and points shall be complete and firm and shall be tight and undamaged. The manual operating mechanism should be well lubricated and open and close flexibly. No damage is allowed to the inlet and outlet gas joints of the cylinder; Each part of the cylinder and air piping system shall be carefully inspected, and there shall be no leakage affecting the service performance. No-sag is allowed in the pipe, the annunciator should be in good condition, the indicator light of the annunciator should be in good condition, and the connecting threads of both pneumatic annunciator and electric annunciator should be in good condition without leakage. The valves on pneumatic devices shall be intact, free from leakage, flexible to open and smooth in airflow. The whole pneumatic device should be in normal working condition with a flexible opening and closing.
