Principle Overview:

The opposed-end check valve, also known as reverse-flow valve, backflow valve, backpressure valve, or one-way valve, is a type of automatic valve that automatically opens and closes based on the force generated by the flow of the medium within the pipeline. 

The opposed-end check valve is suitable for various pipelines with nominal pressure ranging from PN1.0 MPa to 42.0 MPa, Class 150 to 2500; nominal diameter ranging from DN12 to 1200 mm, NPS 1/2 to 48; and working temperatures ranging from -196 to 540 °C. It is used to prevent the backflow of the medium. By selecting different materials, it can be applicable to various media such as water, steam, oil, nitric acid, acetic acid, strong oxidizing media, and urea.

Standards and Specifications:

1. Design and Manufacturing: API 594, API 6D, JB/T 8937;

2. Structural Length: API 594, API 6D, DIN 3202, JB/T 8937;

3. Pressure-Temperature Grades: ANSI B 16.34, DIN 2401, GB/T 9124, HG 20605, SH 3406, JB/T 74;

4. Testing and Inspection: API 598, JB/T 9092;

5. Pipe Flanges: JB/T 74-90, GB/T 9112-9124, HG 20592-20635, SH 3406, ANSI B 16.5, DIN 2543-2548, GB/T 13402, API 605, ASME B 16.47.

Structural Characteristics:

1. Short structural length, with its structural length being only 1/4 to 1/8 of that of traditional flange check valves;

2. Small volume and light weight, with its weight being only 1/4 to 1/20 of that of traditional flange check valves;

3. Quick valve disc closure, with small water hammer pressure;

4. Can be used in both horizontal and vertical pipelines, in terms of installation;

5. Smooth flow path, low fluid resistance;

6. Sensitive operation, good sealing performance;

7. Short valve disc stroke, small valve closure impact force;

8. Overall structure, simple and compact, attractive in appearance; 

9. Long service life and high reliability.