Certification information of check valves, introduction of national standard check valves

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

The check valve is an automatic valve, and its main function is to prevent the backflow of the medium, prevent the pump and the drive motor from reversing, and the discharge of the container medium. Check valves can also be used on lines that supply auxiliary systems where pressure may rise above the system pressure. Check valves can be mainly divided into swing-type check valves (rotating according to the center of gravity) and lifting check valves (moving along the axis).

The purpose of this type of valve is to allow the flow of the medium in only one direction and to prevent it from flowing in one direction. Usually this kind of valve works automatically, and the disc opens under the action of fluid pressure flowing in one direction; When the fluid flows in the opposite direction, the fluid pressure and the self-coincident spike of the disc act on the valve seat, thus cutting off the flow. Among them, float check valve, internal thread check valve, butterfly check valve belong to this type of valve, which includes swing check valve and lifting check valve.

The swing check valve has a medium hinge mechanism and a door-like disc resting freely against the sloping seat surface. In order to ensure that the disc reaches the right position on the seat surface every time, the disc is designed with a hinge mechanism so that the disc has enough room to swing and that the disc is in true and full contact with the seat. The disc can be made entirely of metal, or it can be inlaid with leather, rubber, or synthetic overlay, depending on the performance requirements.

When fully open, the fluid pressure is virtually unimpeded, so the pressure drop through the valve is relatively small. The disc of the lift check valve is located on the seat seal on the valve body. Except for the disc that can be raised and lowered freely, the rest of the valve is like a globe valve, the fluid pressure lifts the disc from the sealing surface of the valve seat, and the backflow of the medium causes the disc to fall back to the valve seat and cut off the flow.

Depending on the conditions of use, the disc can be an all-metal construction or in the form of a rubber pad or rubber ring inlaid on the disc holder. Like globe valves, the passage of fluid through a lift check valve is narrow, so the pressure drop through a lift check valve is greater than that of a swing check valve, and the flow rate of a slip and swing check valve is less restricted.

It belongs to special equipment.

The special equipment manufacturing license includes application, acceptance, product trial production and type test, appraisal and review, approval, certification and other procedures

A) the application for the manufacturing license of the unit (hereinafter referred to as the applicant unit) to fill in the application form (the application from the relevant ****, in quadruplicate) to the license implementation authority to apply, and attach the following materials (one copy each):

1.A copy of the industrial and commercial business license obtained in accordance with the law or the registration and registration certificate issued by the relevant departments in accordance with the law;

2.Other materials specified in the relevant safety technical specifications.

2) Acceptance. The licensing implementing organ shall review the application materials, and if it agrees to accept it, it shall sign the acceptance opinion on the application form and return it to the applicant unit. If they do not agree to accept the application, a notice of non-acceptance shall be issued to the applicant unit.

3) Product trial production and type test.

If it is necessary to carry out product trial production or type test in accordance with the regulations, the applicant shall prepare the trial product or conduct the type test after acceptance. (The type test institution shall be announced by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on the relevant **).

After completing the type test, the unit undertaking the type test shall issue a vertical limb test report to the applicant unit.

4) Invite an appraisal and evaluation agency.

The applicant shall bring the approval of the application materials and the type test report of the relevant equipment, and invite the appraisal and evaluation agency to conduct on-site appraisal and evaluation (the appraisal and evaluation agency shall be announced by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on the relevant **).

The appraisal and review procedures shall be carried out in accordance with the safety technical specifications such as the manufacturing license rules, and the appraisal and evaluation agency shall issue an appraisal and review report to the licensing authority after completing the on-site appraisal and evaluation work.

5) Examination and approval and issuance of certificates.

After review, the license implementation authority performs the approval procedure, and issues the "Special Equipment Manufacturing License" (one original and one copy) if the conditions are met. If the conditions are not met, a decision not to grant permission shall be issued to the applicant unit.

The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China entrusts the provincial Bureau of Quality and Technical Supervision to be responsible for the acceptance and approval of the licensing projects, and issues the license in the name of the General Administration of Quality Supervision, Inspection and Quarantine.

Type: Design & Fabrication, Structure Length, Flange Size, Pressure Temperature, Test-Inspection, Swing Check Valve GB12236, GB12221, GB9113

JB79 GB9131 GB T13927JB 9092 Lifting Check Valve GB12235 Valve Body, Bonnet, Disc Stem Sealing Surface Gasket Sealing Surface Operating Temperature Applicable Media WCB WCB 1CR13 Reinforced Flexible Graphite.

1Cr13 flexible graphite.

PTFE Gear Gasket 13Cr

STL Material: Nylon 425 Water Vapor Oil WC6 WC6 540 WC9 WC9 570 ZGCR5MO ZGCR5Mo 550 ZG1CR18NI9TI ZG1CR18NI9TI ZG1CR18NI9TI 200 Nitric Acid ZG1CR18NI12MO9TI ZG1CR18NI12MO9TI 200 Acetic Acid Name Check Valve H Transmission Mode Code Connection Code 0 0 Female Thread 1 0 0 External Thread 2 0 0 Flange 4 0 0 Welding 6 0 0 Pair Clamp 7 0 0 Clamp 8 0 0 Ferrule 9 0 0 Two Different Links 3 Check Valve Structure Code Check Valve Structure Code Lifting Straight-through 1 Swing Swing Single Valve 4 Vertical 2 Multi-Valve 5 Angle 3 Double Valve 6 Rotary Butterfly Check Valve 7 Globe Check Valve 8 Sealing Face or Lining Material Table: Sealing Face or Lining Material Code Sealing surface or lining material Code Steel alloy t Fluorinated steel D Rubber x cemented carbide y Nylon plastic n lining j Fluoroplastic F lining Lead q Tin-based bearing alloy (Bar alloy) b Enamel C Alloy steel H Boronized steel P Note: When the sealing surface material is the same as the valve body material, it is indicated by "W".

The national standard check valve refers to the valve that automatically opens and closes the valve disc by relying on the quiet flow of the predecessor of the medium to prevent the medium from backflowing, also known as check valve, check valve, reverse flow valve, and back pressure valve.