A brief analysis of the general technology of slow

2022-09-22
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A brief analysis of the general technology of slow closing check valves for drainage

now the relevant contents of the standard are introduced as follows:

the standard is applicable to nominal impact test; Collision experiment; Pressure PN4.0MPa, nominal diameter DN? 4000mm, the working temperature is not greater than 80 ℃, and the working medium is the flange connected slow closing check valve of drinking water, raw water, industrial circulating water, seawater, sewage and other non corrosive media. The technical requirements in the standard are as follows:

1 the structural length of the flange connected slow closing check valve should be in accordance with the provisions of gb/t12221 or as agreed by the user. When the butterfly check valve is opened, the extension length of the butterfly plate should not affect the use

2 flange connection size and sealing surface type shall comply with the provisions of gb/t17241.6, gb/t17241.7 or gb/t9112

3 the minimum 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 materials of main parts such as valve body, bonnet, disc (butterfly plate), valve shaft of slow closing check valve shall comply with the provisions of gb/t12236, gb/t12238 or gb/t13932

4.2 the material of the slow closing device damping piston cylinder should meet the requirements of system pressure. The surface of the piston and piston rod should be plated with hard chromium to realize the high-end of the product and the internationalization of the market. The piston and piston rod sealing ring should adopt oil-resistant materials such as stack clear rubber

4.3 the anti-corrosion paint and rubber seals used in the inner cavity of the slow closing check valve body for water supply and other metal parts in contact with water shall be non-toxic and odorless

5 the closing process of slow closing check valve should be divided into two stages: quick closing and slow closing, and its slow closing time should be adjustable

6 if there is no curve coordinate, double-click the result display bar; Check the force, displacement and deformation (i.e. extension) in the status display column. The slow closing opening of the check valve disc of the slow closing check valve, i.e. the extension length of the slow closing piston, should be adjustable throughout the whole process.

7 the check valve disc (butterfly plate) of the slow closing check valve should be opened and closed flexibly without jamming

8 the damping piston in the slow closing device must be sensitive. When the check upper disc (butterfly plate) is opened, it can automatically and quickly extend to the predetermined working position, and when the check disc (butterfly plate) is closed to the slow closing position, it can play an effective slow closing role. The capacity of the damping piston cylinder in the slow closing device should match the regulating valve used to avoid excessive force of the damping piston cylinder and pipeline, so as to achieve the purpose of adjustable hammer elimination

9 the slow closing device of external damping slow closing check valve and hydraulic butterfly check valve shall be attached with a mechanism to monitor the liquid level of damping medium

10 the self damping slow closing check valve does not allow raw water and sewage with solid particles to enter the slow closing device directly, so as to avoid blocking or damaging the seals

11 the hydraulic butterfly check valve and butterfly slow closing check valve should be equipped with an indicating mechanism that correctly displays the opening position of the butterfly plate

12 the hydraulic butterfly check valve should be equipped with a hammer or an accumulator as an additional force source in case of power failure to automatically close the valve

13 the relevant connection, transmission and support parts of the slow closing device shall have sufficient strength and rigidity

14 hydraulic device: standard hydraulic parts and electrical components should be products with reliable quality, good performance and long service life, and should be tested according to the provisions of their respective relevant standards, and can be used only after passing the test. After the hydraulic device is assembled, various parameter performance tests and adjustments should be carried out to make it meet the design requirements of the valve "lightweight refers to the production of slow closing packaging with less materials"

15 the external paint layer and color of the slow closing check valve should be uniform, the appearance should be smooth and flat, and there should be no scars, sagging, blistering, obvious cracks and other defects

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