The relevant content of the standard is introduced as follows:
The standard applies to the nominal pressure PN4.0MPa, the nominal diameter DN?4000mm, the working temperature is not more than 80 °C, the working medium is the flange connection of drinking water, raw water, industrial circulating water, seawater, sewage and other non-corrosive media. Close the check valve. The technical requirements in the standard are as follows:
1 The structural length dimension of the flange-connected slow-closing check valve shall be in accordance with the provisions of GB/T12221 or as agreed by the user. When the butterfly check valve is opened, the length of the disc extension shall not affect the use.
2 Flange connection size and sealing surface type should meet the requirements of GB/T17241.6, GB/T17241.7 or GB/T9112.
3 The small wall thickness of the valve body shall comply with the provisions of GB/T12236, GB/T12238 or GB/T13932 standards.
4 materials
4.1 The main parts and materials of the valve body, valve cover, valve flap (butter) and valve shaft of the slow-closing check valve shall be in accordance with GB/T12236, GB/T12238 or GB/T13932.
4.2 Slow-closing device damping The material of the piston cylinder should meet the requirements of system pressure. The surface of the piston and piston rod should be hard chrome plated. The piston and piston rod sealing ring should be made of oil-resistant materials such as stack rubber.
4.3 Anti-corrosion coatings and rubber seals used in the body cavity of the slow-closing check valve for water supply and other metal parts in contact with water shall be non-toxic and tasteless.
5 The closing process of the slow closing check valve should be divided into two stages: speed closing and slow closing. The slow closing time should be adjustable.
6 The slow closing degree of the check valve of the slow-closing check valve, that is, the extended length of the slow-closing piston should be adjustable throughout.
7 The check valve flap (butter) of the slow-closing check valve should be flexible and open, and there is no jamming.
8 The damping piston in the slow-closing device must be sensitive. When the valve flap (sliding plate) is opened, it can automatically and quickly reach the predetermined working position. When the valve flap (butterfly) is closed to the slow-closing position, it can start. Effective slowing down. The capacity of the damping piston cylinder in the slow-closing device should be matched with the regulating valve used, so as to avoid the force of the damping piston cylinder and the pipe being too high, and the purpose of adjusting and eliminating the hammer is achieved.
9 The external damping damping check valve and the liquid control butterfly check valve should be equipped with a mechanism for monitoring the liquid level of the damping medium.
10 Self-damping slow-closing return valve does not allow raw water, sewage, etc. with solid particles to directly enter the slow-closing device to avoid clogging or damage the seal.
11 The liquid control butterfly check valve and the butterfly slow closing check valve shall be provided with an indicating mechanism for correctly displaying the position of the butterfly opening.
12 hydraulic control butterfly check valve should be equipped with a weight or accumulator as an additional force source to automatically close the valve when power is off.
13 The slow-closing device shall have sufficient strength and rigidity for the connection, transmission and support.
14 Hydraulic devices: Standard hydraulic components and electrical components should be selected with reliable quality, good performance and long service life, and should be tested according to the relevant standards. After the hydraulic device is assembled, the performance test and adjustment of each parameter shall be carried out to meet the design requirements of the valve "slow closing".
15 The external paint layer and color of the slow-closing check valve should be uniform and uniform, and the appearance should be smooth and flat. There should be no defects such as scars, sag, blistering and obvious cracks.
The standard applies to the nominal pressure PN4.0MPa, the nominal diameter DN?4000mm, the working temperature is not more than 80 °C, the working medium is the flange connection of drinking water, raw water, industrial circulating water, seawater, sewage and other non-corrosive media. Close the check valve. The technical requirements in the standard are as follows:
1 The structural length dimension of the flange-connected slow-closing check valve shall be in accordance with the provisions of GB/T12221 or as agreed by the user. When the butterfly check valve is opened, the length of the disc extension shall not affect the use.
2 Flange connection size and sealing surface type should meet the requirements of GB/T17241.6, GB/T17241.7 or GB/T9112.
3 The small wall thickness of the valve body shall comply with the provisions of GB/T12236, GB/T12238 or GB/T13932 standards.
4 materials
4.1 The main parts and materials of the valve body, valve cover, valve flap (butter) and valve shaft of the slow-closing check valve shall be in accordance with GB/T12236, GB/T12238 or GB/T13932.
4.2 Slow-closing device damping The material of the piston cylinder should meet the requirements of system pressure. The surface of the piston and piston rod should be hard chrome plated. The piston and piston rod sealing ring should be made of oil-resistant materials such as stack rubber.
4.3 Anti-corrosion coatings and rubber seals used in the body cavity of the slow-closing check valve for water supply and other metal parts in contact with water shall be non-toxic and tasteless.
5 The closing process of the slow closing check valve should be divided into two stages: speed closing and slow closing. The slow closing time should be adjustable.
6 The slow closing degree of the check valve of the slow-closing check valve, that is, the extended length of the slow-closing piston should be adjustable throughout.
7 The check valve flap (butter) of the slow-closing check valve should be flexible and open, and there is no jamming.
8 The damping piston in the slow-closing device must be sensitive. When the valve flap (sliding plate) is opened, it can automatically and quickly reach the predetermined working position. When the valve flap (butterfly) is closed to the slow-closing position, it can start. Effective slowing down. The capacity of the damping piston cylinder in the slow-closing device should be matched with the regulating valve used, so as to avoid the force of the damping piston cylinder and the pipe being too high, and the purpose of adjusting and eliminating the hammer is achieved.
9 The external damping damping check valve and the liquid control butterfly check valve should be equipped with a mechanism for monitoring the liquid level of the damping medium.
10 Self-damping slow-closing return valve does not allow raw water, sewage, etc. with solid particles to directly enter the slow-closing device to avoid clogging or damage the seal.
11 The liquid control butterfly check valve and the butterfly slow closing check valve shall be provided with an indicating mechanism for correctly displaying the position of the butterfly opening.
12 hydraulic control butterfly check valve should be equipped with a weight or accumulator as an additional force source to automatically close the valve when power is off.
13 The slow-closing device shall have sufficient strength and rigidity for the connection, transmission and support.
14 Hydraulic devices: Standard hydraulic components and electrical components should be selected with reliable quality, good performance and long service life, and should be tested according to the relevant standards. After the hydraulic device is assembled, the performance test and adjustment of each parameter shall be carried out to meet the design requirements of the valve "slow closing".
15 The external paint layer and color of the slow-closing check valve should be uniform and uniform, and the appearance should be smooth and flat. There should be no defects such as scars, sag, blistering and obvious cracks.
POCT Analyzer,POCT Analyser,POCT Chemistry Analyzer,POCT Hematology Analyzer
ZSL MED , https://www.zslmed.com