Vihung - Model API 6D -Axial Flow Check Valve

The streamlined design of the axial flow check valve permits its fully opening at low flows and fluid velocities, getting a low pressure drop. Its spring assisted system and metal-to-metal sealing features provides a non-slam closing and little maintenance.

Based on Venturi effect, the reduced flow area allows a fast full opening and the disc stays in position against its backstop on normal flow conditions. In a flow reduction situation, the spring reacts quickly, overcoming the fluid force and turning the disc back to a full close position with a short displacement. This system greatly reduces the reaction time, with a slam free response that protects critical elements of the pipeline.

This kind of valves can be used in multiple applications, like oil & gas, petrochemical, power generation, chemical... in any process in which water hammering is a real issue, and are an alternative to Quick Closing Non Return Valves, assisted with an actuator and used in those systems with higher protection requirements. Axia Flow Check Valve is the preferred solution for critical non-return applications such as the protection of rotating equipment and systems where low pressure loss, stable operation and dynamic behaviour are essential.

Vihung Valves designs and manufactures axial flow check valves in sizes from 2` to 84`, with an ANSI class from 150LBS to 2500LBS.

• Axia Flow Check Valve,Solk) disc, non-slam nozzle check valve
• Basic Design: API 6D.ASME B16.34
• Sizes: 2"-84"
• Pressures: ANSI 150LB-2500LB
• Materials: Carbon / Stainless / Alloy Steel / Monel / Hastelloy / Titanium
• Trim Material: 13CR, Stellite, 304SS, 316SS,Monel
• Spring Material: 17-4PH, AISI 302,lnconelX-750 Ends: RF, RTJ, BW
• Face to Face dimension: ANS116.10
• End flange dimension: ANSI B16.5 / ANSI B16.47 Series A or B

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: reduced operating cost 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 a 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 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 back flow 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, VIHUNG axial check valves do not require any maintenance.

Reliable performance prediction:
Both the pressure drop and the dynamic behaviour 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.