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Swing Check Valves

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Swing Check Valves

Swing check valves are unidirectional valves designed to stop reverse flow in pipelines, ensuring that fluid moves only in the intended direction. They are widely used in systems where backflow could damage equipment, contaminate fluid lines, or cause safety hazards. The valve operates using a swinging disc attached to a hinge or shaft. When the fluid flows forward, the disc swings away from the seat, allowing an unobstructed path. When the flow stops or reverses, the disc returns to the seat, creating a seal that blocks reverse movement.

Because of their automatic operation, swing check valves do not require an operator or actuator. This makes them highly reliable in continuous and remote applications such as water distribution, process piping, and pump discharge lines. Their simple, rugged design ensures a long service life with minimal maintenance, making them one of the most widely used types of check valves.

Exceed manufactures swing check valves with a focus on precision sealing, durability, and low pressure loss. By combining robust body construction with carefully engineered disc-seat geometry, Exceed valves deliver reliable protection against backflow across a wide range of applications.

 

Standards:

Manufacturing Std.: BS 1873 / ASME B16.34

Testing & Inspection Std.: API 598

Face to Face: ASME B16.10

End Connections: ASME B16.5

 

Engineering Options:

  • Counterweight / Hydraulic Arrangement: Counterweight and hydraulic damping arrangements for controlled disc movements and reduced slamming.
  • Bypass Arrangement: Bypass connection for pressure equilization and controlled system operation.
  • Stellite Hardfacing: Stellite overlay on seating surfaces for improved resistance to erosion and wear in demanding services.

The working principle of a swing check valve is based on the movement of the disc in response to flow pressure:

  1. Forward Flow (Open Position):
    When fluid enters the valve in the forward direction, the pressure pushes the disc away from the seat. The disc swings upward on its hinge, allowing flow to pass with minimal obstruction. The design of the body and disc ensures that the pressure drop across the valve is low, keeping the system efficient.

  2. No Flow (Neutral Position):
    If forward flow reduces or stops, the disc gradually returns toward the seat. The combination of gravity and the weight of the disc positions it close to closing, ready to respond if backflow begins.

  3. Reverse Flow (Closed Position):
    If flow reverses, backpressure forces the disc tightly against the seat. This creates a seal that prevents reverse movement of fluid. A properly designed swing check valve closes quickly enough to protect equipment like pumps from damage while avoiding water hammer by ensuring smooth disc movement.

This automatic operation makes swing check valves particularly effective in protecting pumps, compressors, and storage systems, as they shut off flow without requiring manual action or external power.

Swing check valves are commonly used:

  • At pump outlets – to prevent reverse flow when pumps shut down.

  • In water supply lines – to stop contaminated or stagnant water from flowing back into clean lines.

  • In process systems – to safeguard heat exchangers, compressors, and storage tanks from reverse pressure.

  • In fire protection systems – to ensure reliable one-way flow in sprinkler and hydrant systems.

  • Automatic Backflow Prevention
    Swing check valves operate automatically without external intervention.
    Exceed ensures precise seat-disc alignment for dependable sealing and reduced leakage risk.

  • Simple, Robust Design
    With only a few moving parts, swing check valves require minimal maintenance and provide long service life.
    Exceed machines its valves to close tolerances and uses quality materials for durability and wear resistance.

  • Low Pressure Drop
    The swinging disc design allows smooth, unobstructed forward flow.
    Exceed optimizes disc geometry to minimize flow resistance and energy loss.

  • Versatile Use
    Suitable for a wide range of fluids including water, steam, oil, and chemicals.
    Exceed offers material and seat options tailored for demanding applications.

No Parts Name Qty. Materials
1 Body 1 ASTM A216 Gr. WCB

ASTM A351 Gr. CF8

ASTM A351 Gr. CF8M
2 Lever 2 ASTM A216 Gr. WCB

ASTM A351 Gr. CF8

ASTM A351 Gr. CF8M
3 Flap 1 ASTM A743 CA15 / ASTM A216 Gr, WCB with SS410 (13% Cr) Overlay

ASTM A351 Gr. CF8

ASTM A351 Gr. CF8M
4 Seat Ring 1 ASTM A268 TP 410

Integrated with Body

Integrated with Body
5 Hinge Pin 1 ASTM A108 Gr. 1045

ASTM A276 Type 304

ASTM A276 Type 316
6 Gasket 1 Spiral Wound Gasket with SS304 Winding and Carbon Filler

Spiral Wound Gasket with SS304 Winding and Carbon Filler

Spiral Wound Gasket with SS316 Winding and Carbon Filler
7 Cover 1 ASTM A36 / ASTM A216 Gr. WCB

ASTM A240 Type 304 / ASTM A351 Gr. CF8

ASTM A240 Type 316 / ASTM A351 Gr. CF8M
8 Stud - Nuts Req. MS - MS / ASTM A193 Gr. B7 - ASTM A194 Gr. 2H

ASTM A193 Gr. B8 - ASTM A194 Gr. 8

ASTM A193 Gr. B8M - ASTM A194 Gr. 8M

 

Service Rating Test Pressure
Material Class Working Pressure @ 38°C Max Temp. Shell Test High Pressure Closure Test (Water)
WCB

150

300

19.6 bar

51.1 bar

425°C

29.4 bar

76.7 bar

21.6 bar

56.2 bar
CF8/CF8M

150

300

19 bar

49.6 bar

425°C

28.5 bar

74.4 bar

20.9 bar

54.6 bar

Important Notes:

1) Temprature shown is the maximum service temprature of the valve. The allowable working pressure decreases as temprature increases. Always refer to the ASME B16.34 pressure-temprature ratings for the exact value at the required temprature.

2) Hydrostatic test pressures are based on API 598 requirements:

  • Body (shell) test = 1.5 x rated working pressure
  • Seat (closure) test = 1.1 x rated working pressure
Size DN F to F ØD ØRF PCD ØM N T
25 127.00 108.00 51.00 79.20 16.00 4 11.00
40 165.10 127.00 73.00 98.5 16.00 4 14.2
50 203.00 152.00 92.00 120.60 19.00 4 15.70
65 216.00 178.00 105.00 139.70 19.00 4 17.50
80 241.00 190.50 127.00 152.40 19.00 4 19.00
100 292.00 229.00 157.00 190.50 19.00 8 24.00
125 330.00 254.00 186.00 215.9 22.00 8 24.00
150 356.00 279.00 216.00 241.30 22.00 8 25.00
200 495.00 343.00 270.00 298.40 22.00 8 28.50
250 622.00 406.00 324.00 362.00 25.00 12 30.00
300 699.00 483.00 381.00 431.8 25.00 12 32.00
350 787.00 534.00 413.00 476.20 28.00 12 35.00
400 864.00 597.00 470.00 539.70 28.00 16 36.50
450 978.00 711.20 533.40 628.60 35.00 24 60.40
500 978.00 774.40 584.20 685.80 35.00 24 63.50
600 1295.00 914.40 692.10 812.80 41.00 24 69.80

(Dimensions above 600mm available on request)

All dimensions are in mm

Size DN F to F ØD ØRF PCD ØM N T
25 203.00 124.00 51.00 89.00 19.00 4 17.50
40 241.00 155.40 73.00 114.30 22.00 4 20.50
50 266.70 165.00 92.00 127.00 22.00 8 22.00
65 292.00 190.50 105.00 149.30 22.00 8 25.00
80 317.50 209.50 127.00 168.10 22.00 8 28.5
100 355.60 254.00 157.00 200.10 22.00 8 32.00
125 400.00 279.40 186.00 234.90 22.00 8 35.00
150 444.50 317.50 216.00 269.70 22.00 12 36.5
200 533.00 381.00 270.00 330.20 25.00 12 41.00
250 622.00 444.50 324.00 387.30 29.00 16 48.00
300 711.00 520.70 381.00 450.80 32.00 16 51.00
350 838.00 584.20 413.00 514.30 32.00 20 54.00
400 863.00 647.70 470.00 571.50 35.00 20 57.00

(Dimensions above 400mm available on request)

All dimensions are in mm

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