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DL/T 2025.2-2019: Guide for the maintenance of power plant valve -- Part 2: Butterfly valve
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Guide for the maintenance of power plant valve -- Part 2: Butterfly valve
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DL/T 2025.2-2019
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Basic data | Standard ID | DL/T 2025.2-2019 (DL/T2025.2-2019) | | Description (Translated English) | Guide for the maintenance of power plant valve -- Part 2: Butterfly valve | | Sector / Industry | Electricity & Power Industry Standard (Recommended) | | Classification of Chinese Standard | F23 | | Classification of International Standard | 23.060 | | Word Count Estimation | 12,123 | | Date of Issue | 2019-06-04 | | Date of Implementation | 2019-10-01 | | Quoted Standard | GB/T 196; GB/T 197; GB/T 21465; DL/T 438; DL/T 746; DL/T 869; DL/T 2025.1; JB/T 5779.1; JB/T 5779.2; JB/T 5779.3; NB/T 47044 | | Regulation (derived from) | Natural Resources Department Announcement No. 7 of 2019 | | Issuing agency(ies) | National Energy Administration | | Summary | This standard specifies the procedures, process requirements and quality standards for the maintenance of butterfly valves in power stations. This standard applies to butterfly valve maintenance of water, steam, oil, air and other piping systems in thermal power plants. Other butterfly valve maintenance can be implemented by reference. | DL/T 2025.2-2019: Guide for the maintenance of power plant valve -- Part 2: Butterfly valve---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Guide for the Maintenance of Power Plant Valve-Part 2.Butterfly Valve
ICS 23.060
F 23
Record number. 63143-2018
People's Republic of China Electric Power Industry Standard
Guidelines for overhaul of power station valves
Part 2.Butterfly Valve
2019-06-04 released
2019-10-01 implementation
Issued by National Energy Administration
Table of contents
Foreword...I
1 Scope...1
2 Normative references...1
3 Terms and definitions...1
4 Structure type...1
5 Valve maintenance...3
5.1 Valve maintenance process...3
5.2 Preparation for maintenance...4
5.3 Disassembly of butterfly valve...4
5.4 Inspection of butterfly valve parts...5
5.5 Maintenance of butterfly valve parts...6
6 Repair process...10
7 Valve replacement...10
8 Assembly and debugging...10
8.1 Assembly...10
8.2 Commissioning...10
9 Quality Control and Acceptance...11
Foreword
"Guidelines for Overhaul of Power Station Valves" is divided into eight parts.
--Part 1.General Provisions
--Part 2.Butterfly Valve
--Part 3.Check Valve
--Part 4.Ball Valve
--Part 5.Gate Valve, Globe Valve
--Part 6.Safety valve
--Part 7.Regulating Valve
--Part 8.Special valves for power stations
--Part 9.Driving Device
This part is Part 2 of "Guidelines for Overhaul of Power Station Valves".
This part is drafted in accordance with the rules given in GB/T 1.1-2009 "Guidelines for Standardization Work Part 1.Standard Structure and Compilation".
This part was proposed by the China Electricity Council.
This part is under the jurisdiction of the Power Plant Valve Standardization Technical Committee.
Drafting organizations of this section. Xi'an Thermal Power Research Institute Co., Ltd., Hunan Agricultural University, State Power Investment Corporation Henan Electric Power Maintenance Engineering Co., Ltd.
Company, Harbin Power Station Valve Co., Ltd. of Harbin Electric Group, China Valve Technology (Changsha) Valve Co., Ltd., Zhejiang Baolong Valve Manufacturing Co., Ltd.
Division, Universal Valve Group Co., Ltd.
The main drafters of this section. Li Yongkang, Tong Chengbiao, Wang Yusheng, Wan Shengjun, Zhai Xingxue, Li Zhiqiang, Tian Shizhong.
This section is the first release.
The opinions or suggestions during the implementation of this part are fed back to the Standardization Management Center of the China Electricity Council (No. 2 Baiguang Road, Beijing)
One, 100761).
Power Station Valve Maintenance Guide Part 2 Butterfly Valve
1 Scope
This standard specifies the procedures, process requirements and quality standards for the maintenance of butterfly valves in power stations.
This standard applies to butterfly valve maintenance of water, steam, oil, air and other piping systems in thermal power plants. For other butterfly valve maintenance, please refer to
Row.
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this
file. For undated references, the latest version (including all amendments) applies to this document.
GB/T 21465 Valve Terminology
DL/T 438 Metal Technology Supervision Regulations for Thermal Power Plants
DL/T 746 Selection Guide for Butterfly Valves in Power Stations
DL/T 869 Welding technical specification for thermal power plant
JB/T 5779.1 General requirements for surface defects of fasteners, bolts, screws and studs
JB/T 5779.2 Fastener surface defect nut
JB/T 5779.3 Special requirements for bolts, screws and studs on surface defects of fasteners
NB/T 47044 Power Station Valve
3 Terms and definitions
The terms and definitions in GB/T 21465, DL/T 746, and Part 1.General Rules apply to this standard.
4 Structure type
5 Valve maintenance
5.1 Valve maintenance process
Valve maintenance should be carried out in accordance with the maintenance process, and the maintenance process should meet the requirements of Figure 6.
Figure 6 Valve maintenance process
5.2 Preparation for maintenance
5.2.1 The preparations for butterfly valve maintenance shall comply with the requirements of Part 1 of the general rules of the power station valve maintenance guidelines.
5.2.2 Before maintenance, the valve power supply should be released, hydraulic or pneumatic actuators should be depressurized, and they should be in a safe position.
5.2.3 For the drive device with spring or hydraulic energy storage components, ensure that the energy has been released and that no automatic opening and closing actions will occur after the power is cut off.
5.2.4 Maintenance personnel should understand the operating conditions and installation positions of the butterfly valve, carefully read the "Product Manual" and related technical drawings and documents, and formulate
Butterfly valve assembly and disassembly process.
5.3 Disassembly of butterfly valve
5.3.1 Before the butterfly valve is disassembled, a technical diagnosis should be carried out to check the internal leakage, external leakage, looseness of the butterfly pin, sealing surface fit, and surface damage.
Clarify the current main problems of the valve. If the valve parts are seriously damaged and the valve has no repair value, the repair work will not be carried out.
Discontinue the valve maintenance program.
5.3.2 The valve should be disassembled at the slightly open position, and all parts should be marked after disassembly.
5.3.3 For butterfly valves with heavy hammers, the heavy hammers should be removed first.
5.3.4 Disconnect the hydraulic system and electrical control system, remove the valve electrical external wiring (if any), and the hydraulic system connection pipeline (if any).
5.3.5 Remove the transmission device (including electric device).
5.3.6 Remove the valve shaft, separate the valve body, butterfly plate, bearing, bushing, end cover, packing; for other parts, such as sealing pressure plate, sealing
Disassemble the sealing ring.
5.3.7 Place the removed valve parts in an orderly manner and mark them as necessary. The removed valve parts should be covered during non-working periods.
Parts should be stored away from moisture, and precision parts should be packaged for storage.
5.3.8 For the case of pressing ring segments, the installation position of each pressing ring shall be recorded in detail and marked.
5.3.9 For all hydraulic ports and pneumatic ports, the pipe ports shall be effectively blocked to prevent foreign matter from entering.
5.4 Inspection of butterfly valve parts
5.4.1 Surface defect inspection
5.4.1.1 Before the inspection, remove the rust and grease on the surface of the parts, and apply anti-rust oil to the processed surface.
5.4.1.1 Visually inspect the inner and outer surfaces of the valve, sealing surface, valve shaft matching surface, flange surface, bearing and other surfaces, and combine with appropriate tools
Tool for surface appearance defect inspection, inspection items and criteria meet the error! The reference source was not found. Provisions.
5.4.1.2 The surface of the parts should be smooth, smooth and free of obvious defects. For surface defects like cracks, further inspections should be made, and important parts should be
Line non-destructive testing.
5.4.1.3 Surface defects can be repaired by welding and grinding. Weld the important relative moving surfaces (including sealing surfaces) as a whole
When making up, the machine should be reprocessed.
5.4.2 Roughness check
5.4.2.1 The surface of the valve shaft, the surface of the shaft hole, the sealing surface and the mating surface shall be inspected for roughness. The inspection standards shall meet the requirements of Table 2.
5.4.2.2 Use the comparison method to check the surface roughness, and measure the suspicious parts.
5.4.3 Weld inspection
5.4.3.1 The welds of the pressure-bearing parts of the valve and all surfacing surfaces shall be visually inspected, including the welds between the valve seat and the valve body, etc.
Damage inspection.
5.4.3.2 The weld joint shall be free of defects such as cracks, pores, sand holes, slag inclusions, etc. Crack-type defects shall be subject to non-destructive testing after the defects are removed.
5.4.3.3 The inspection of the connection weld between the valve body and the pipeline shall be carried out in accordance with the requirements of DL/T 438.
5.4.3.4 Weld defects should be repaired in accordance with the requirements of DL/T 869 and NB/T 47044.
5.4.4 Inspection of main cooperating parts
5.4.4.1 The matching parts of the valve seat and sealing ring, valve shaft and butterfly plate, valve shaft and bearing, butterfly plate pin and pin hole, key and keyway should be inspected.
5.4.4.2 The matching dimensions and assembly clearance shall meet the requirements of the design drawings. The inspection standard of the main matching parts should meet the error! The reference source was not found.
Provisions.
5.4.4.3 When the tolerance or fit clearance requirements are exceeded or there are defects such as looseness or jamming, the parts shall be ground or replaced to make them conform to the table
3 regulations.
5.5 Maintenance of butterfly valve parts
5.5.1 Valve body maintenance
5.5.1.1 Visually inspect the parts of the valve body eroded by the medium. When the wear is serious, use a thickness gauge to measure the wall thickness of the valve body. The thickness reduction rate cannot be low.
10% of the design thickness.
5.5.1.2 Grind the pits, rust and other defects on the non-machined surface of the valve body, and the grinding depth should not exceed the error! The reference source was not found.
Provisions.
5.5.1.3 When the partial wall thickness of the valve body is lower than the standard minimum wall thickness, local welding repair and grinding, return to the factory for treatment or replacement shall be carried out. In the repair process
Existing casting defects such as slag inclusion, porosity and shrinkage can be partially repaired under the premise of meeting the strength, but should be recorded in the maintenance record sheet.
5.5.1.4 The rubber-lined (fluorine) butterfly valve shall undergo surface inspection of its lining. The lining defect of the rubber-lined (fluorine) butterfly valve should be repaired.
The method and testing requirements are in accordance with the process requirements of the manufacturer.
5.5.2 Butterfly board maintenance
5.5.2.1 Visually inspect the inner and outer surfaces of the butterfly plate to check the degree of wear, erosion and damage.
5.5.2.2 Visually inspect the mating surfaces of the butterfly plate and other parts, and inspect the dimensions of the shaft hole and pin hole.
5.5.2.3 The connecting pin hole of the butterfly plate and the valve shaft shall be hinged with a pin.
5.5.2.4 Check the installation mating surface of the butterfly plate sealing ring, and repair the defects.
5.5.2.5 Repair or repair the damaged area of the butterfly plate, and return to the factory for treatment or replacement if the damage is serious and cannot be repaired.
5.5.2.6 Check the lining of the rubber-lined (fluorine) butterfly valve. Repair the defective part of the lining, the repair method and inspection requirements are in accordance with the manufacturer’s
Process requirements.
5.5.3 Bearing inspection
5.5.3.1 Carry out visual and dimensional inspection of the inner and outer surfaces of the bearing, and replace the out of tolerance.
5.5.3.2 Check the wear of the thrust bearing of the valve shaft. The clearance exceeds the design allowable value and should be replaced.
5.5.3.3 If the valve shaft bearings are installed in pairs and need to be replaced, they should be replaced in pairs.
5.5.4 Secondary maintenance of main seal
5.5.4.1 Carry out surface defect inspection and surface roughness inspection on the valve seat and main sealing ring, and repair them if they are unqualified.
5.5.4.2 When the sandwich metal sealing ring is defective, it shall be replaced as a whole.
5.5.4.3 The surface defects of the seal pair shall be ground and polished, and the polished thickness of the hard seal shall not be greater than 0.1mm.
5.5.4.4 If the following conditions exist, argon arc welding local repairs should be performed before grinding and polishing.
a) Local defects are small but widely distributed, such as pits, indentations, grooves, scratches, erosion, small surface cracks, etc.;
b) The overall size is reduced too much after local defects are ground.
5.5.4.5 The parts should be replaced or returned to the factory in the following situations.
a) The size of the parts after grinding cannot meet the assembly requirements;
b) The required welding repair area is too large, and heat treatment cannot be performed on site;
c) There are large crack defects, especially penetrating cracks.
5.5.4.6 If the sealing position of the lining sealed butterfly valve is severely worn, the lining layer should be replaced as a whole; the wear of the non-sealed contact position should be
The manufacturing process requires repair.
5.5.4.7 When the butterfly valve has a rubber sealing structure, the surface inspection should be carried out first, and the rubber sealing ring should be replaced if there are surface defects and cannot be sealed.
And conduct material inspection.
5.5.5 Valve shaft maintenance
5.5.5.1 Carry out surface defect inspection, roughness inspection and coordination inspection on the valve shaft, and non-destructive testing should be used for suspicious defects.
5.5.5.2 For the valve shaft whose curvature is more than 3‰, the valve shaft or the entire valve should be replaced.
5.5.5.3 When repairing valve shafts that have undergone nitriding, phosphorous nickel electroless plating and surface hardening, the following items should be checked on the surface hardened layer.
a) Defects such as wear and scratches on the hardened layer of the valve shaft;
b) Check the surface hardness;
c) The surface hardening layer roughness Ra≤1.6μm, the surface roughness of the valve shaft in contact with the filler Ra≤1.6μm;
d) Check the size of the fit between the valve shaft and the packing.
5.5.5.4 If the disc pin has loose traces, the valve shaft should be installed into the disc, and the disc pin hole should be reamed and distributed.
5.5.5.5 Repair of valve shaft defects shall be handled according to the following principles.
a) When the valve shaft wear and corrosion depth are less than 0.20 mm and meet the design and use requirements of the valve shaft, re-surface hardening treatment;
b) The contact parts of the valve shaft packing are uniformly pitted or worn with a depth of more than 0.20 mm, which should be replaced or reworked by overlay welding;
c) The valve shaft should be an integral structure, and the valve shaft should be replaced if it is cracked or broken. It should not be used in combination with welding.
5.5.6 Maintenance of valve seals
5.5.6.1 Valve seals include packing and other valve shaft sealing parts, as well as sealing parts on the valve seat, sealing ring and end cover.
5.5.6.2 For butterfly valves with a service life of more than three years, all rubber seals should be replaced; if the service life is less than three years, but the resilience is poor,
The seal should also be replaced.
5.5.7 Fastener maintenance
5.5.7.1 Valve fasteners include flange bolts, packing gland bolts, pressure ring bolts, transmission bolts, nuts, etc.
5.5.7.2 The surface inspection of fasteners should be free of deformation, cracks, corrosion, wrinkles/folds, dents, scratches, nicks, gouges, cuts,
For defects such as damage, the judgment standard shall be in accordance with the provisions of JB/T 5779.1, JB/T 5779.2, JB/T 5779.3.
5.5.7.3 Fasteners are not allowed to be repaired by welding. When the thread has burrs and local bumps on the surface, the thread can be reshaped and repaired, and the quality requirements should be met
5.5.7.4 For fasteners with surface treatment requirements, the surface must be retreated after damage is repaired.
5.5.7.5 It shall be replaced when it cannot be repaired on site, and shall meet the design requirements of the manufacturer.
5.5.8 Overhaul of transmission
5.5.8.2 For manual butterfly valves or electric butterfly valves, check the gap between the handwheel and the handwheel drive shaft, the gears, worm gears, and worms in the transmission device.
Surface wear, the wear of the internal bearings of the transmission, repair or replace if necessary.
5.5.8.3 Check or replace the lubricating grease in the transmission box to ensure that the transmission box is sufficiently lubricated. For the electric device failure found during the overhaul, press
Follow the instructions for use and maintenance of the electric device, or coordinate with the manufacturer of the electric device.
5.5.8.4 For hydraulic valves with a service life of more than five years, disassemble the hydraulic cylinder and replace all seals.
5.5.8.5 For hydraulic valves, check the gaps between the matching parts of the hydraulic transmission device. If there is obvious looseness, respond
The corresponding parts are repaired or replaced; at the same time, the moving mating surface is filled with oil or grease to ensure sufficient lubrication between the moving parts.
5.5.8.6 The assembly of the transmission device should be positioned accurately to meet the requirements of the butterfly valve for full opening and closing.
5.5.9 Hydraulic system maintenance
5.5.9.1 Clean or replace the suction filter, oil return filter element or filter screen.
5.5.9.2 Clean the inside of the fuel tank to ensure that no dirt remains.
5.5.9.4 If the service life is more than five years, all rubber seals of the hydraulic system shall be replaced.
5.5.9.5 All control valves and valve blocks of the hydraulic system shall be cleaned.
5.5.9.6 Replace the control valve or the control valve that refuses to operate due to the wear factor.
5.5.9.7 The oil pipeline of the hydraulic system should be cleaned and blown clean with compressed air.
5.5.9.8 Check the pressure gauge, pressure switch, overflow valve and other regulating components, reset or replace if they cannot work normally.
5.5.9.9 Check the pressure tank (accumulator), and report any suspected defects to a professional for re-examination or replacement.
5.5.10 Pneumatic device maintenance
Pneumatic devices should be overhauled by professionals or manufacturers. The matching pneumatic triple or double parts should be overhauled together.
5.5.11 Overhaul of electric device
Electric devices should be overhauled by professionals or manufacturers.
6 Repair process
The maintenance process complies with the requirements of Part 1.General Provisions of Guidelines for Overhaul of Power Station Valves.
7 Valve replacement
The valve replacement complies with the requirements of Part 1.General Regulations of Power Station Valve Maintenance Guidelines.
8 Assembly and debugging
8.1 Assembly
8.1.1 The following conditions shall be met before the valve is assembled.
a) The sub-item cleaning and maintenance work of valve body, butterfly plate, valve shaft, bearing and other parts is completed;
b) The connecting flange of the valve and the pipeline has been overhauled; the welding joint of the butt-welded valve is qualified;
c) The medium flow channel and pipeline inside the valve body shall be clean and free of foreign matter;
d) The valve seals are in place;
e) The hydraulic system, electrical system, pneumatic device, electric device, etc. have been maintained according to the instructions.
8.1.2 Assemble the butterfly valve according to the assembly process, and measure to ensure that the butterfly plate is centered relative to the valve body.
8.1.3 After assembly, check the anastomosis of the seal pair, which can be carried out by pressing red lead (or blue oil, etc.). The sealing surface should be smooth, with even contact
Continued without disconnection. The metal sealing butterfly valve is checked with a feeler gauge, and there should be no gap in the anastomosis part.
8.2 Debug
8.2.1 The following inspection items are required before valve commissioning.
a) The electric drive device should be connected to the valve normally, and the over-torque protection should be intact;
b) The electric control box, hydraulic station, drive device and valve are connected correctly, and check whether the setting value meets the design requirements of the manufacturer;
c) The operating force of the manual valve should meet the following requirements. if the diameter or length of the handwheel and handle is not greater than 320mm, only one person is allowed to operate it.
If the diameter or length of the handwheel or handle is greater than 320mm, two people are allowed to operate together, or one person is allowed to use appropriate
The lever (generally no more than 0.5m long) operates the valve.
8.2.2 After assembly, adjust the valve electric device and hydraulic drive device, including the following.
a) Debug the switching direction (forward and reverse) of the drive device and valve;
b) For hydraulic drive devices, check the sealing condition of the hydraulic connection pipeline of the hydraulic control valve;
c) Check stroke and opening indication;
d) Check the opening and closing time;
e) Carry out interlocking debugging of valve and DCS system.
8.2.3 After the commissioning and the test are qualified, the insulation and decoration of the valve shall be restored, the valve identification shall be complete, the inspection and repair site shall be completed, and the valve shall have the operating conditions
Pieces.
9 Quality control and acceptance
9.1.1 The quality control and acceptance of valves shall comply with the provisions of Part 1.General Provisions of this standard.
9.1.2 After maintenance, the butterfly valve shall be subjected to sealing test and action test according to the corresponding product standard. Welding repair or valve body on the pressure part of the valve body
If it is replaced as a whole, a strength test shall also be carried out, and special circumstances shall be determined through consultation between the maintenance unit and the user.
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