General provisions
1. This job description defines the functional duties, rights and responsibilities of a repairman.
2. A person with a secondary education and appropriate training in the specialty is appointed to the position of a repairman.
3. The mechanic-repairman must know the structure of the repaired equipment, units and machines; machine regulation rules; ways to eliminate defects in the process of repair, assembly and testing of equipment, units and machines; device, purpose and rules for the use of used control and measuring instruments; design of universal and special devices; methods of marking and processing simple various parts; system of admissions and landings; quality and roughness parameters; properties of acid-resistant and other alloys; the main provisions of preventive maintenance of equipment; design features of the repaired equipment, units and machines; technical conditions for repair, assembly, testing and regulation and for the correct installation of equipment, units and machines; technological process of repair, assembly and installation of equipment; rules for testing equipment for static and dynamic balancing of machines; geometric constructions with complex markup; methods for determining premature wear of parts; ways to restore and harden worn parts and apply a protective coating.
4. A repairman is appointed to the position and dismissed by order of the head of the institution in accordance with the current legislation of the Russian Federation.
5. The mechanic-repairman reports directly to the deputy head of the ACS, or the deputy head of engineering, or the deputy head of construction, or the head of the economic department, or the head of the technical department, or the head of the construction department.
Job Responsibilities
Implementation of repair work. Disassembly, repair, assembly and testing of components and mechanisms. Repair, installation, dismantling, testing, regulation, adjustment of equipment, units and machines and delivery after repair. Locksmith processing of parts and assemblies. Manufacture of complex devices for repair and installation. Preparation of defective repair reports. Performing rigging work using lifting and transport mechanisms and special devices. Identification and elimination of defects during the operation of the equipment and when checking during the repair process. Accuracy and load testing of repaired equipment.
Rights
The repairman has the right to:
1. make proposals to the management of the institution on the organization and conditions of their work;
2. use information materials and legal documents necessary for the performance of their duties;
Educational practice PM №1
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4. improve your skills.
A repairman enjoys all labor rights in accordance with the Labor Code of the Russian Federation.
Responsibility
The Maintenance Technician is responsible for:
1. timely and high-quality implementation of the duties assigned to him;
2. organization of their work, timely and qualified execution of orders, instructions and instructions of the management, regulatory legal acts on their activities;
3. compliance with internal regulations, fire safety and safety;
4. maintaining the documentation provided for by the current regulatory legal acts;
5. prompt action, including timely informing the management, to eliminate violations of safety, fire and other rules that pose a threat to the activities of the institution, its employees and other persons.
For violation of labor discipline, legislative and regulatory legal acts, a repairman may be brought in accordance with applicable law, depending on the severity of the misconduct, to disciplinary, material, administrative and criminal liability.
Valve maintenance
The frequency and scope of maintenance and repair of shut-off valves are determined by the manufacturer's instructions and the schedule approved by the chief engineer of the operating organization.
On the spot (in order to speed up the process), the repair of shut-off valves is partially limited to grinding small valves or taps, which consists in the fact that the spool or plug is rubbed with a fine
emery with machine oil to the nest. In this case, the stem seals and plugs are also stuffed. Grooving of spools, cheeks, rods, ground-boxes is done in workshops on lathes or lapping machines. The detected defects are eliminated in the same ways as during the repair of shutoff valves.
To speed up the operations of turning on and off pipelines and to facilitate the repair of shut-off valves, wells with walls made of rubble stone or reinforced concrete prefabricated elements are constructed on all tie-ins and on all burst gates. They are equipped with durable covers and well-marked signs.
In the working condition of the stop valves, the passage of the medium through the stuffing box and gasket seals is not allowed.
The technical condition of the valve during operation must be determined by diagnostic control. Acoustic emission (AE), ultrasonic (US) and other non-destructive testing methods are used to determine the technical condition of the valve body and welds.
The diagnostic control of the gate valve is combined in time with a major overhaul and is also carried out when excessive stresses are detected on the nozzles or when failures occur in the operation of the gate valve according to the criteria for limit states. When diagnosing, devices and AE sensors and ultrasonic testing devices or flaw detectors are used.
Diagnostic control and a conclusion based on its results are carried out by specialized organizations that have the permission of the Gosgortekhnadzor of Russia, or specialists from RNU, TsBPO in the presence of a developed and approved method of diagnostic control.
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Checking the tightness of the valve gate during operation can be carried out by acoustic emission leak detectors.
At existing main oil pipelines, valves are also tested for strength and density of materials and welds, tightness in relation to the external environment, seal tightness and performance. The testing of fittings is combined in time with the testing of oil pipelines or is carried out after the overhaul of oil pipelines.
The test mode and test pressures are established depending on the period and parameters of operation of oil pipelines in accordance with the regulatory documents governing testing on existing oil pipelines.
Locking and control devices. Shut-off valves- type of pipeline fittings designed to block the flow of the medium. It has the widest application and usually makes up about 80% of the total number of products used. Shut-off valves include both test-bleed and control-bleed valves used to check the level of a liquid medium in tanks, take samples, bleed air from upper cavities, drain, etc. Fig. 5, a, c) and valves (Fig. 5, b). The control valve differs from the shut-off valve only in the design of the valve (spool). The valve has a tail device that allows you to smoothly change the flow area of the valve. In addition, fine threads are cut into the control valve spindle.
Rice. 5. Shutoff valves:
A - through passage valve (shut-off): 1
- cap-handwheel; 2 -
spindle head; 3 - spindle; 4
- stuffing box; 5
- lid; 6
- spool; 7 - body; b - brine valve: 1
- frame; 2 - cheeks; 3 - wedge; 4 -
stock; 5 - stuffing box; 6
- flywheel; V - two-way shut-off freon valve: 1
- frame; 2 - spindle; 3 - stuffing; 4 -
screw; 5 - gasket, 6
- cap; 7 - branch pipe; 8 -
tee; 9 -
cap nut.
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Shut-off and control valves are installed so that the direction of movement of the refrigerant coincides with the direction of valve lift (under the valve). A shut-off valve is usually installed before each control valve, since the control valve cannot be used as a shut-off valve.
On fig. 5, V a two-way freon angle valve with a small flow section is shown. A two-way valve allows you to turn off one of the passages in working condition or connect both passages at the same time. Freon compressors often use a valve of this design.
Similar information.
1. General Provisions
1.1 Maintenance of shut-off valves is carried out at least once a year. 1.2 Maintenance of shut-off valves is carried out by teams of workers in the amount of at least three people when working on an underground gas pipeline and at least two people on an aboveground gas pipeline under the guidance of a specialist.2 Work order
2.1 During the maintenance of shut-off valves installed on aboveground and underground gas pipelines, the following types of work are performed: - cleaning from dirt and rust; - external inspection to detect distortions, shells, cracks, corrosion and other defects; - checking the tightness of welded, threaded, flanged joints and stuffing box seals with special devices (gas indicators or gas analyzers); - elimination of leaks in flange connections by tightening bolts or changing gaskets; - cleaning the flanges before installing new gaskets; - elimination of gas leakage in stuffing boxes by tightening the stuffing box or changing stuffing box packing; - acceleration of the worm at the valves and, if necessary, its lubrication (preventing the complete shutdown of the gas pipeline); - checking the operability of the drive device of the gate valves; - coloring of shut-off valves. 2.2 During the maintenance of the fittings installed in the well, the following types of work are additionally performed: - checking the condition of the covers of gas wells and wells for gas contamination; - pumping water from wells (if necessary); - checking the presence and serviceability of shunting electrical jumpers, the state of sealing of gas pipeline cases, structures of wells, brackets, stairs. 2.3 Before carrying out maintenance work on shut-off valves on underground gas pipelines, the ECP must be turned off. 2.4 Maintenance work on stop valves installed above ground is carried out in the following order: - maintenance work on stop valves is carried out according to 20.2.1; - the tightness of the joints is checked with a foaming solution or an instrumental method. 2.5 Maintenance work on the fittings in the well is carried out in the following order: - the well cover is cleaned from dirt, snow, ice; - the condition of the cover in the wells is checked; - the well is checked for gas content with special devices through a hole in the cover of the gas well; - the lid of the well rises with a hook; - the well is ventilated for 15 minutes and re-checked for gas contamination; - if necessary, pumping water from the well; - in the absence of gas pollution, one of the workers in the rescue belt descends into the well, the workers of the brigade located on the surface of the earth must hold the ends of the ropes from the rescue belt of the worker in the well and continuously monitor him; - a cable (shunt) jumper between the detachable parts of the gas pipeline is installed on the gas pipeline to the places cleaned from paint; - a worker in the well performs maintenance work on stop valves of 20. 2.1; - at the end of maintenance, checks the tightness of connections and fittings; - after lifting the working well, it is checked for gas content; - the lid of the well is closed. 2.6 During the maintenance of a ball valve installed in the ground without a well, under the carpet, the following types of work are performed: - the cover of the carpet is cleaned; - the carpet is checked for gas pollution by the instrumental method through a hole in the cover of the carpet; - carpet cover opens; - the carpet is cleaned of debris and water (if necessary); - the absence of gas leakage under the cover of the ball valve stem is checked by loosening the bolt; - the cover of the valve stem is removed and the operation of the valve in the “open-closed” positions is checked, while not allowing the valve to close completely; - checking the serviceability of the drive unit; - the tightness of the joints is checked with a foaming solution or an instrumental method; - the carpet is checked for gas contamination and closed. 2.7 During maintenance of the valve, the following types of work are performed: - clean the valve body and bolted connections of the cover and flanges from dirt and rust; - tighten the gland seal; - check the tightness of the bolts of the flange connections; - diverge and lubricate the drive; - check the tightness of the connections with a foaming solution or an instrumental method. 2.8 During the maintenance of the cone crane, the following types of work are performed: - clean the crane from dirt and rust, wipe it with a rag; - adjust the smoothness of the course by tightening the tension nut; - check the tightness of the connections with a foaming solution. 2.9 During the maintenance of the ball valve, the following types of work are performed: - clean the valve from dirt and rust, wipe it with a rag; - disperse the crane; - center the smoothness of movement by tightening the tension nut; - check the tightness of the connections with a foaming solution or an instrumental method. 2.10 If a gas leak is detected during the maintenance of shut-off valves, it is necessary to eliminate the gas leak in the stuffing boxes by tightening the stuffing box or changing the stuffing box packing. When tightening the stuffing box, the pressure box must be tensioned evenly with cap bolts. One-sided tightening of the bolts can cause the axle box flange to break. It is also necessary to ensure that the gland is not overtightened, as this can lead to bending of the spindle and failure of the valve. 2.11 In the event of a gas leak during maintenance of the stop valves installed in the well, those leaks are eliminated that can be eliminated by replacing the stuffing box in the valve or by packing the chamber of the cone valve with grease. For other leaks, work in the well should be stopped.3 Quality control of works
The tightness of joints and fittings installed on the gas pipeline and in the well is checked with a foaming solution or an instrumental method.4 Presentation of work results
Data on the work done on the maintenance of shutoff valves are entered in the passport for the gas pipeline and stored for one year.5 Special requirements
5.1 For the performance of work on the maintenance of shut-off valves, a work permit is issued for the performance of gas hazardous work in the form PB 12-529-03, which provides for the development and subsequent implementation of a set of measures for the preparation and safe conduct of work. 5.2 Workers are allowed to work who have passed certification in industrial safety in the amount corresponding to their official duties and the profile of the work performed, and who have received a permit to perform gas hazardous work. 5.3 Before performing work on the maintenance of shut-off valves, the work manager is obliged to instruct the workers on the technological sequence of operations and the necessary safety measures and record the passage of the briefing with the signatures of the workers - members of the team in the work permit for the performance of gas hazardous work. 5.4 The presence and serviceability of personal protective equipment are determined when issuing a work permit for the performance of work. 5.5 Responsible for the availability of personal protective equipment for workers, their serviceability and application skills is the head of the work. 5.6 After receiving the task, the team members are required to prepare: - the necessary personal protective equipment (hose mask, gloves, overalls, first aid kit, rescue belts and ropes) and check their serviceability; - tools, equipment and technical equipment necessary for the performance of work, check their serviceability and compliance with safety requirements. 5.7 In case of detection of gas in the well, the worker, with the permission of the work manager, must descend into the well in a gas mask. 5.8 If the gas concentration is dangerous (more than 20% of the lower flammability limit), it is forbidden to descend into the well. 5.9 When working in a gassed environment, non-ferrous metal tools should be used. In the absence of such a tool, the cutting and impact parts of the tool should be lubricated with grease, grease or other greases to prevent the formation of a spark. 5.10 If a gas leak is detected in the fittings, cracks, distortions and other damages, work in the well must be stopped and the head of the service must be notified. 5.11 Before starting work on the roadway, the following safety measures must be taken: - workers and specialists performing work must wear signal color vests; - install fences on the side of traffic at a distance of 5 m from an open well, and put up warning signs at a distance of 10–15 m; - conduct continuous monitoring of passing vehicles; - if it is necessary to restrict traffic, coordinate the arrangement of road warning signs with the traffic police. 5.12 One should descend into the well only along the brackets or stairs. When descending the brackets, you need to make sure that they are securely fastened. The metal ladder must be of sufficient length with a device for fixing it at the edge of the well. 5.13 Check the tightness of all welded, threaded, flanged joints and stuffing box seals with a foaming solution or instrumental method. 5.14 A worker descending into the well must be in overalls and shoes without steel forgings and nails. 5.15 When cleaning fittings from rust and dirt, it is necessary to use goggles and gloves. 5.16 The fittings in the well should be painted with a hand brush (pneumatic paint spraying is not allowed) and in a gauze mask. A limited amount of paint should be supplied to the well. During the painting period, it is necessary to constantly ventilate the well. Do not use dyes containing volatile solvents. Paint should be stored in hermetically sealed containers. 5.17 All team members must be able to provide first aid for burns, bruises, suffocation, gas poisoning and electric shock. 5.18 In case of detection of any serious damage that may lead to an emergency and require immediate elimination, the ADF team should be called. Prior to the arrival of the ADS brigade, take security measures (ventilate the well, prevent unauthorized persons from approaching it and the appearance of open fire, etc.).All newly installed fittings at the main pipeline facilities must have:
- certificates of conformity certifying its compliance with the requirements of State standards and regulatory documents of Russia;
- permission from Rostekhnadzor for the right to produce and use these products.
During operation, valve maintenance is carried out.
Gate valves.
The technological mode of operation of the gate valves, indicating the type of control (local or remote), the pressure drop on them and the maximum operating pressure is established on the basis of the design documentation.
The operation of gate valves with a half-closed gate is prohibited. An exception is emergency situations at the pumping station, when the valves can be used for a short time to throttle the pressure.
Once a shift, the on-duty personnel conduct technical inspections of valves, during which they check:
- tightness of flange connections and stuffing box seals;
- smooth movement of moving parts;
- electrical drive performance.
As part of maintenance, the following works are performed once a month:
- minor repairs of fittings that do not require a special shutdown of main pumps (cleaning of external surfaces, elimination of oil leaks, maintenance of sites, etc.);
- visual check of the condition of all parts of the valves;
- checking the presence of lubrication in the electric drive gearbox and replenishing it;
- checking the tightness of the stuffing box seal and flange connections;
- checking the operability of the electric drive (terminal fastening, overload protection, operation of limit switches and torque limiting clutch);
- valve tightness control.
To ensure the tightness of flange connections, they are tightened twice a year (in spring and autumn). The same procedure is performed if a leak is detected in a flange connection.
Wrapping of valve flange connections must be carried out at a pressure reduced to a safe level. It must be borne in mind that before tightening the flange connection of the body and the cover of the wedge gate valve, it is necessary to slightly open the wedge in order to avoid damage to the threaded bushing.
The determination of the torque of the electric drive of the valve is carried out by measuring the magnitude of the current strength of its electric motor. Its value should not exceed the nominal value by more than 10%.
When carrying out seasonal maintenance, once every 6 months, the tightness of the valve gate is checked. It is combined with scheduled shutdowns of the main pipeline and PS.
To control the tightness of the shutter, a pressure drop is created equal to 0.1-0.2 MPa at an overpressure of at least 0.4 MPa. The criteria for assessing tightness are the change in pressure in the cut-off sections of the pipeline and the presence of noise from leaks of the pumped liquid through the gate.
The change in pressure in the cut-off section of the pipeline is controlled by the readings of pressure gauges (not lower than the first class of accuracy with a division value of not more than 0.05 MPa) for at least 30 minutes. The shutter is considered non-hermetic if the change in pressure in half an hour is 0.1 MPa or more.
Registration of the noise of leaks of the pumped liquid through the gate is carried out by acoustic devices (leak detectors, sound level meters). The fixation of such noise in the valves of the unit for connecting the pumping station to the main pipeline, the discharge and suction lines of the main pumps (aggregate valves), the chamber for starting and receiving the SOD, the receiving and distributing branch pipes of the tanks indicates a leakage of the shutter. In other cases, leaks should not exceed the allowable value determined by the tightness class of the valves.
The criteria for their inoperability are:
- leaks that cannot be eliminated by additional tightening through stuffing box seals and flange connections;
- leaks of the pumped medium in the gate, exceeding the permissible value;
- jamming of the moving parts of valves when opening and closing valves;
- increase in response time in excess of the allowable;
- failure of the drive.
Valves that do not work are repaired.
Information on how to eliminate their possible malfunctions is given in the table below.
Possible valve malfunctions and ways to eliminate them
|
Malfunction |
Possible reasons |
Solutions |
|
Passage of the medium when the valve is closed |
Violate tightness due to wear or contamination of the surfaces of the body sealing rings and the wedge or disc. Insufficient force on the flywheel (less than calculated). Insufficient torque developed by the electric drive. Formation of a deposit of solid particles or resin in the lower part of the body |
Dismantle valve, clean, grind or replace O-rings. Increase the force on the flywheel to the calculated. Check torque clutch setting. Check the voltage at the input. Check the technical condition of the electric motor. |
|
Passage of the medium through the connection of the body with the lid |
Loss of tightness due to insufficient tightening of the bolts. Gasket damaged. The sealing surfaces of the housing or cover are damaged. |
Tighten the screws evenly. Replace gasket. Remove the cover, repair the damage and rub the sealing surfaces |
|
The passage of the medium through the stuffing box |
The gland packing is not sufficiently sealed. Wear of stuffing box packing. Damaged spindle surface |
Tighten the gland nuts evenly. Refill the stuffing box or replace the stuffing box. Repair spindle surface damage |
|
Shutter movement with delays or increased torque |
Damaged wedge or disc guides. Precipitation of solid particles or resin on the guides |
Disassemble valve and repair damage. Dismantle valve and remove sediment |
|
Increased flywheel torque required for closing |
Lack of lubrication in movable mates |
Lubricate moving joints |
|
Electric drive does not work |
No drive power |
Check and fix the power supply line of the electric drive |
Pressure regulators. During the maintenance of pressure regulators, which is carried out by maintenance personnel once a month, the following work is performed:
- external inspection to check the tightness of the body and connections;
- checking the tightness of stuffing box seals and, if necessary, tightening them;
- control of the integrity and serviceability of the shaft, drive levers, as well as the gearbox;
- checking the presence of lubrication in the electric drive and gearbox (if necessary - replenishment);
- checking and tightening the contact connections of the electric drive.
For the block of pressure regulators as a whole, the following are produced:
- control of the accuracy and synchronism of the operation of the shutters;
- checking the functioning of the block heating system.
Safety valves.
The integrity of the body of safety valves can be compromised due to corrosion, fatigue phenomena, increase in allowable pressure.
Due to damage to the sealing surfaces or foreign objects on them, misalignment of the valve parts and other reasons, it is possible for the pumped liquid to pass through the valve plug at a pressure lower than the calculated one.
Due to the excessively high flow rate of the discharged liquid, as well as deposits on the surface of the supply pipeline or branch pipe, pulsation may occur - a quick and frequent closing and opening of the safety valve.
Finally, the safety valve may simply not operate at a given set pressure due to an incorrectly adjusted or too stiff spring, as well as increased friction in the spool guides.
Therefore, the scope of maintenance of safety valves includes:
- external inspection to determine the integrity of the hull;
- checking the valve operation at a given pressure;
- tightness and pulsation control.
Maintenance of safety valves is carried out by service personnel 2 times per shift.
Check valves.
Similar to gate valves, maintenance of check valves is carried out by service personnel once a shift and includes:
- checking the tightness of the seals (with the elimination of detected leaks);
- control of damping devices performance and their restoration;
- cleaning the outer surface.
Checking the tightness of non-return valves is carried out once a year, similarly to gate valves. It must correspond to the values given in the table below.
Tightness standards for non-return valves
Electric drives.
Reliable operation of the electric drive is ensured by:
- maintaining its components and parts in working condition;
- careful fastening of the drive to the valve, the electric motor to the gearbox, the limit switch to the drive;
- timely operation of limit switches and torque limiting clutch;
- high-quality lubrication of its rubbing parts.
Therefore, during the maintenance of the electric drive, a visual check of the condition of the electric drive and supply cables, the condition and fastening of the motor terminals, checking the protection of the electric motor against overloads, checking the operation of the limit switches and their revision, checking the operation of the torque limiting clutch, and also check the presence of grease in the bearings and gearbox and replenish it.
The main malfunctions of electric drives and ways to eliminate them are given in the table below.
Possible malfunctions of electric drives and ways to eliminate them
|
Malfunction manifestation |
Possible reasons |
Solutions |
|
Manual control |
||
|
When the actuator is switched to manual control, the handwheel rotates idly |
The clutch cams do not interlock; clutch cams are broken; the head of the rod or thrust burst; the key is broken on the splined shaft of the worm or on the flywheel |
Remove the manual control assembly, check the clutch and gear engagement |
|
When switching the drive from electric and vice versa, the rod does not move or goes tight |
The pins touch the walls of the grooves of the worm; jamming of the rod or thrust in the guides; spring is broken. Jamming of cam clutches on the worm shaft |
Remove and inspect the manual control and lock assembly, check the condition of the pins and spring. Check the condition of the worm clutches and keys on it |
|
The force on the flywheel increases so much that it is impossible to open or close the valve |
Seizure of moving parts of valve or actuator |
By turning the handwheel in the opposite direction, repeat closing or opening. If the jam persists, find the cause and correct the problem. |
|
Pointer needle does not rotate during stroke |
Malfunction of transmission from the drive drive shaft to the cam roller of the limit switch. Loose screw locking disc with arrow |
Check transmission. Open the pointer, remove the glass and tighten the locking screw |
|
Electrical control |
||
|
The motor does not rotate when the start buttons are pressed. |
Power circuit defective. The starter does not work. No voltage on the control panel |
Check power circuit. Check starter for proper operation. Check starting equipment |
|
When the start buttons are pressed, the engine rotates idly, and the electric drive stops |
The actuator has not been switched to electrical control. The key on the worm or on the motor shaft has been cut off. The set screw has loosened and the coupling on the motor shaft has advanced towards the bearing |
Switch the drive to electric control. Disassemble the drive, find out the fault and fix it. Remove the motor, put the coupling in place and lock with a screw |
|
In the end positions of the shut-off valve, the signal lamps do not light up. |
Lamps burned out. There is no voltage. The electric drive is stopped in the intermediate position of the locking element |
Replace lamps. Check control circuit. Check the position of the shut-off device according to the local index and start the drive by pressing the appropriate button |
|
"Closed" and "Open" lights are on at the same time |
Short circuit between the wires going to the limit switch |
Disconnect the signal wires from the limit switch and eliminate the short circuit |
|
During the movement of the electric drive in the direction of closing, the LM lamp lit up and the electric motor turned off |
Seizure of moving parts of valve or actuator |
Find out the cause of the jam and fix it |
|
When starting the electric actuator with two-sided torque limitation from the fully closed position to the opening side, the valve passage does not open and the LM lamp lights up |
Insufficient torque in opening direction, torque limiting clutch engages |
Press the clutch spring in the opening direction |
|
When the "Closed" position is reached, the electric motor does not automatically turn off |
Loose closing cam. Malfunction of the disengaging mechanism of the torque limiting clutch |
Check the setting of the cams and the serviceability of the microswitches and, if necessary, replace the faulty one. Adjust the clutch, check the function and, if necessary, replace the microswitch |
|
When the "Open" position is reached, the electric motor does not automatically turn off |
Weak opening cam. Faulty microswitch |
Check the setting and make adjustments in the "Open" position. Check and, if necessary, replace the microswitch |
|
Inadmissible leakages of the medium between the sealing surfaces of the valve |
Insufficient torque. Solid particles have entered between the sealing surfaces of the fitting. Valve sealing surfaces worn or damaged |
Compress the clutch spring. Clean the passage and sealing surfaces of the valve. Repair sealing surfaces |
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Types of valves and their use
Pipe fittings are used by enterprises of the energy industry, housing and communal organizations, in the metallurgical, chemical, food and other types of industry.
Table of varieties and classifications of valves for the pipeline.
Shut-off, phase-separating, protective, distribution, high-pressure, shut-off and control and control valves act on the flow area, determine changes in the flow of substances, and actually control them. The task of shutoff valves is to start and stop the flow of the working medium. Timely diagnostics and high-quality repair of gate valves ensure the efficient operation of the entire system, reliable fixation of the extreme positions of the assembly (“closed”, “open”).
Gate valve and its varieties
The movement of the flow of gas, vapor or liquid is regulated by the most common type of valves - the valve. It is conditionally possible to classify devices according to several characteristics.
By type, valves are distinguished:
The sealing surfaces of the gate of a parallel gate valve are parallel to each other.
- full bore;
- constricted (the diameter of the pipeline exceeds the diameter of the seal ring opening).
According to the shape of the valve, valve valves are distinguished:
- wedge;
- parallel.
Feature - stopping the movement of the flow of substances by the translational rotation of the shutter perpendicular to the main flow of the transported substance. The sealing surfaces of the wedge gate are located at a certain angle in relation to each other. All types of wedges are made of high alloy steel. Application - transportation of ammonia (liquid and gaseous), steam and water, non-aggressive oil products.
The sealing surfaces of the gate of a parallel gate valve are parallel to each other. There are single-disk (gate) and double-disk valve valves.
According to the type of spindle movement there are gate valves:
- with a rotating spindle (translational-rotational and translational movements);
- with rising stem and spindle (rotary movements only).
Rotating stem valves are used in pipelines where it is necessary to provide friction lubrication of the stem nut and spindle and there is no threat of corrosion of the assembly. Gate valves with a rising stem are higher than rotating ones, due to their technical characteristics they are used in all other systems.
The cast iron valve is used to start and completely stop the movement of the flow of substances. The maximum operating temperature is 225°C.
According to the type of material, valves are distinguished:
- steel;
- cast iron.
A steel valve blocks movement in the pipeline. Permitted working substances are steam, water, non-aggressive oil products in gaseous and liquid form. They are used to work with different levels of pressure and passages in a temperate climate along the entire length of the pipeline.
The cast iron valve is used to start and completely stop the movement of the flow of substances. The maximum operating temperature is 225°C. Allowed substances are steam, oil products, oil, water. Installation on a horizontal and vertical pipeline is allowed, taking into account the installation features.
Both types of gate valves belong to the category of repairable fittings with a forced duration of operation.
Separately, it is isolated, which consists of an elastic pipe placed in a protective housing flanged on the flanges. There is no contact with the working environment. The principle of operation is one-sided or two-sided overlapping of an elastic hose (pinching). Application - transportation of abrasive pulps, oil products, sludge, aggressive substances. The medium temperature should not exceed 110°C, and the pressure in the pipeline should not exceed 6 kgf/cm2.
Use, repair and diagnostics of gate valves
Installation and maintenance of devices must be carried out by highly qualified specialists.
The use of valve valves in technological and transport pipelines at key and auxiliary enterprises of various types of industry, in energy systems, in gas, oil and water pipelines is due to the following technical characteristics:
- long service life under adverse conditions;
- low hydraulic resistance;
The installation and maintenance of the devices must be carried out by specialists of a high category with a sufficient level of knowledge, permission to carry out a specific operation, possessing the skills to use a particular type of valve.
The main cause of valve malfunction is damage to the surface of the sealing rings due to the ingress of foreign small particles (sand, scale, etc.), while the tightness of the structure is violated, and the transported substance leaks. In addition to significant material losses, when hazardous or aggressive substances are transported through a pipeline with faulty components, environmental damage is possible, and in the most difficult situations, there is a threat to the lives of workers involved in the process.
Upon completion of the work, specialists test the units for the tightness of the seals, test the performance of the device.
Timely diagnostics and repair of the technical condition of the unit affects the quality and efficiency of the system.
To troubleshoot, depending on the location of the damaged unit, observing safety rules, the valves are disassembled, and upon completion of the work they are assembled with a standard tool in specially equipped workshops or directly in the pipeline system. The employee responsible for carrying out the work is obliged to ensure adequate protection of the threaded and sealing elements from damage, to prevent foreign particles from entering the assembly cavities. Upon completion of the work, specialists test the units for the tightness of seals, the shutter, the gasket connection, and test the device's performance.
Repair and dismantling of valve valves is prohibited if:
- there is pressure in the valve cavity or system;
- the medium remains in the device.
It is unacceptable to use knots to regulate the flow.
Stop valve repair technology (gate valves)
- Disassembly, cleaning, defect detection.
- Hull restoration. Anti-corrosion treatment is carried out, grooves are machined under the sealing elements, surfacing is performed.
- Elimination of defects in the cover and body by metal sampling.
- Restoration of tightness of the node. Sealing elements are fixed in various combinations, according to the type of valve. Spent saddles and gate are eliminated, new ones are installed.
- The spindle is restored by surfacing, the thread is calibrated.
- Complete restoration of the gland assembly by replacing the sealing elements (bearings, seals, cuffs, pressure and support rings).
- New belleville springs, shields and pressure valve are installed.
- A new steering wheel is being restored or machined.
- Tests are carried out (hydraulic or pneumatic) and diagnostics for tightness, unit strength.
- The product is preserved and painted.
Each of the repaired products goes through several stages of control: visual, technical and instrumental, in accordance with the legislative acts of the Russian Federation and the requirements of manufacturing enterprises.
The cost of repair work to restore valve valves in most cases ranges from 30 to 50% of the original cost of the product. At the same time, technical and operational characteristics are preserved, the service life is extended, and the efficiency of the pipeline system is increased.
The invention is intended for the repair of shut-off pipeline valves. A method for repairing gate valves, mainly wedge gate valves, by installing finished seats in body bores with a gap on a self-hardening adhesive composition, followed by assembly and curing of the assembled adhesive composition. Before assembly, threads are cut in the bores of the body and on the saddles. Each saddle is made with an annular radial protrusion. After that, the saddles are screwed onto the adhesive self-hardening composition into the threaded bores of the body. In this case, an elastically deformable element is installed between the annular radial protrusions of the seats or the ends of the seats and the body. This allows the screw-in seat to self-align along the wedge, and one elastically deformable element ensures that all gaps are removed, which increases the tightness of the seat-to-body connection. This implementation reduces the complexity and increases the reliability of valve repairs. 3 ill.
The invention relates to the engineering industry, in particular to the repair of pipeline valves. A known method of restoring the sealing fields of the shutter, which consists in welding a hard stainless alloy directly on the body and the valve wedge, followed by machining and lapping (see A.F. Pongilsky. Locksmith for the repair of pipelines and steam-water fittings. M .: Higher school, 1973). This method is quite laborious, requires special, precise and sophisticated equipment. There is also known a method of repairing wedge gate valves (see A.S. 310078), which consists in installing in a gap in the bored grooves of the body and wedge finished, for example, metal rings on a self-hardening composition, followed by assembly of the wedge and body, holding the assembly until the composition is cured . The disadvantages of this method include the possibility of incomplete fit of the sealing rings of the body and the wedge to each other (and hence the lack of tightness) and the impossibility of self-installation in the absence of a side gap between the ring and the groove. And if these gaps are sufficient for self-adjustment of the rings, it is possible to extrude the self-curing composition before its polymerization begins, which means that there is no elastic compression of the rings to each other, which also leads to loss of tightness or the appearance of incomplete contact of the rings with the adhesive composition, which reduces the reliability of the connection. Moreover, this method is not applicable to valves with screw-in seats (see D.F. Gurevich. Calculation and design of pipeline fittings. L .: Mashinostroenie, 1969, Fig. 129-131). The objective of the invention is to reduce the complexity and increase the reliability of the repair. The technical result is achieved by the fact that the sealing fields of the wedge and screw-in saddles are mechanically processed "as cleanly", i. with the removal of the minimum allowance until the wear traces disappear, the sealing fields of both the body seats and the wedge are lapped, threads are cut on the seats in the body bores, after which they are screwed onto the adhesive self-hardening composition into the threaded bores of the body, while between the annular radial protrusions of the seats or the ends of the saddles and the body install an elastically deformable element. The essence of the invention is illustrated by drawings: Fig. 1 shows a wedge gate valve with screw-in saddles in the section, in Fig. 2 - view A in Fig. 1, variant, in Fig. 3 - view A in Fig. 1 option. Seats 3 are installed on the thread 2 in the body 1 with a gap 4 in which a self-hardening composition 5 is placed, limited by an elastically deformable element 6 or 7 installed between the body 1 and the annular radial protrusion 8 or the end face 9 of the screw-in seat 3, the sealing field 10 of which interacts with the sealing field 11 wedge 12. After disassembly, the seats 3 are cleaned of dirt, the sealing fields 11 of the wedge 12 are treated “as clean” and lapped, the threads of the seat and body bores are cut or the existing threads are loosened with a gap sufficient for self-adjustment, then the sealing fields 11 of the wedge 12 are also treated “as cleanly” and lapped their. After that, the thread of the seat 3 is covered with a self-hardening composition 5, elastically deformable elements 6 or 7 are installed and the seat 3 is screwed into the body 1, then the wedge 12 is inserted into the body 1, taking into account the overlap of the sealing fields of the wedge and the seat, ensuring the tightness of the product, and leave it assembled until self-denial. The valve is ready for operation. Depending on the degree of wear of the sealing fields of the seats 10 and the wedge 11, one or two seats are installed on the elastic element 6. Thus, the minimum machining "as pure", lapping four fields, threading - this is the amount of machining of the proposed method, which is much less than known analogues. The gaps in the interface allow the screw-in seat to self-align along the wedge, and one elastically deformable element allows you to select all the gaps in the seals.
Claim
A method for repairing gate valves, mainly wedge valves, by installing finished seats with a clearance in body bores on a self-hardening adhesive composition, followed by assembly and curing of the assembled adhesive composition, characterized in that before assembly, threads are cut in the body bores and on the seats, each seat being made with an annular radial protrusion, after that the seats are screwed onto the adhesive self-hardening composition into the threaded bores of the body, while an elastically deformable element is installed between the annular radial protrusions of the seats or the ends of the seats and the body.
Similar patents:
This invention relates to a shut-off valve comprising a body (1), two O-rings (20) located in this body (1), and two gate discs (12) located between these O-rings (20), which, with the help of an actuator (7 ) can be brought into contact with both O-rings (20). According to the invention, it is proposed to provide each slide disc (12) on its side facing the other slide disc (12) with a recess (28) in which the corresponding pressure block (22a, 22b) is located, each pressure block (22a, 22b) on its facing to the other pressure nut side has a recess (34, 37), while both recesses (34, 37) together form a space (40), in which a package (23) of Belleville springs is placed, containing several Belleville springs (41) with the first elastic force and the first stroke of each spring and several Belleville springs (42) with the second elastic force and the second stroke of each spring, wherein the first elastic force of the spring is greater than the second elastic force of the spring, and the first stroke of the spring is less than the second stroke of the spring. 6 w.p. f-ly, 4 ill.
The invention relates to the field of mechanical engineering, in particular to a parallel pipeline valve with a rising spindle, and can be used as pipeline equipment for various purposes. The gate valve consists of a body 1 with cheeks 2, a retractable spindle 3, a wedge spacer element 4 attached to it, gate disks 5, a cover 6 with a stuffing box assembly 7. Upper stops 8 are made on the body 1, and figured (in our case, T-shaped) grooves. On the side surfaces of the wedge spacer element 4, there are reciprocal protrusions to the T-shaped groove. In the lower inner surface of the housing 1, lower stops 9 are placed to limit the vertical downward movement of the gate disks 5. To create an additional force for lifting the wedge spacer element 4 and prevent premature lifting of the gate disks 5, springs 10 with pushers 11 are placed in the wedge spacer element 4, and on the rear Stops 12 for pushers 11 are attached to the surfaces of the shutter disks 5. The invention is aimed at improving the reliability of operation due to reduced wear of the seals while simplifying the design and improving its manufacturability. 1 z.p. f-ly, 3 ill.
The invention relates to the engineering industry, in particular to the repair of valves