Axial Check Valve

Description

What is an Axial Flow in the Check Valve?

Axial flow in the check valve means the fluid or gas flowing parallel to the axis. It is an axial flow shuttle structure design, and the disc assembly with spring has cushioning and anti-vibration functions. When the medium flows downstream, it will push open the disc and the fluid through the body via axial flow channel circulation. And the spring here has a cushion effect to avoid the impact vibration between the disc and the body when a standard check valve opens. When the medium flows in the opposite direction, the disc closes very quickly, and the disc and the valve seat are tight-fitted to cut off the fluid from the reverse flow direction.

The axial flow check valves have a fast response and silent non-slam issue against pressure surge or damage from water hammer and are particularly designed for fast-reversing systems where backflow is a regular crisis.

What is an Axial Flow Check Valve?

An axial flow check valve is a kind of silent check valve. The check valve is driven by the medium itself and automatically opens and closes the valve disc. Generally, it is used to prevent the backflow of fluid or gases. A flow check valve can be called a one-way valve, non-return valve, backflow valve, backstop valve, and back pressure valve. An axial flow check valve has been a popular industrial valve since 2008. This valve has the function of the general check valve and is designed with a shock-absorbing spring, combined metal seat, and soft seat structure, which is easy for end-user maintenance on site.

The axial flow check valve adopts a particular sealing structure. Whether the downstream pressure is high or low, the valve is permanently closed tightly and has excellent shutoff performance. It overcomes the disadvantage of the lack of shutoff performance of the general check valve at low back pressure. ZECO Valve produced an axial flow check valve that has a unique axial flow shuttle structure. It has the advantages of small flow resistance, significant flow coefficient, compact design, etc. It is the best valve for oil and gas gathering and transmission pipeline systems, especially for the outlet of oil transmission pumps.

Specifications of Axial Flow Check Valve

• VALVE DESIGN
  • based on API 6D and customer requirements
• TEMPERATURE RANGE
  • -150 to 662°F (-101 to 350°C)
• SIZE
  • NPS 2 – 56 (DN 50-1400)
• PRESSURE RATING
  • ASME 150 – ASME 2500
• FACE-TO-FACE
  • As per API 6D standard
• END CONNECTIONS
  • RF, RTJ as per B16.5 &B16.47
  • BW, Butt Welded as per B16.25
• BODY DESIGN
  • Cast one piece / bolted two pieces for size >20 inch.
  • Forged bolted one-piece/ three-piece
• SEAT DESIGN
  • Metal-seated with hard facing on disk and seat

How are Axial Check Valves used?

Axial check valves are specifically designed for fast-reversing systems where backflow is a constant concern. It is categorized as a non-slam check valve as the valve closes without slamming meaning no excess pressure spikes are created. Most axial flow check valves are spring-loaded, with a single low-mass disc, which facilitates fast, dynamic response to a reduction in flow. Due to having a single disc and spring when the disc is opening, the force is balanced resulting in an even flow.

Features of Axial Check Valves

• Axial flow
  • Streamlined flow path through full-port expanded body avoids turbulence and prevents erosion and vibration. Process downtime and maintenance costs are eliminated.
• Low pressure loss
  • The full opening flow passage and high-pressure recovery of the venturi-shaped body result in very low pressure loss and reduced operating costs of pumps and compressors.
• Tight shut-off
  • Tight shut-off is obtained by means of metal-to-metal sealing between the disc and the seat. This sealing is not affected by erosion and deformation of material (like with a soft seal).
• Low cracking pressure
  • The stability of a compressor system during startup benefits from low cracking pressure. This is achieved with a large disc that has identical effective pressure areas on both sides (line contact sealing).
• Easy opening and stable operation
  • The low static pressure in the venturi-shaped throat area creates a pressure differential over the disc, resulting in an easy opening. The axial check valve responds smoothly to changes in flow and remains stable when it is supposed to be.
• Non-slam operation
  • The spring-assisted design ensures ultra-fast closing with virtually no backflow and pressure surges in critical applications such as multi-pump systems or LNG trains.
• Maintenance free
  • Internal construction is based on the application of sound basic mechanical engineering principles. Consequently, ZECO axial check valves do not require any maintenance.
• Reliable performance prediction
  • Both the pressure drop and the dynamic behavior can be predicted with great accuracy, based on full-scale laboratory flow tests and a mathematical model developed in cooperation with a recognized fluid hydraulics laboratory.