Why check valves, the operational benefits. A check valve simply prevents the process flow from reversing, permitting gases and liquids to flow only in one direction . The fluid/gases flowing in the desired direction open the valve and the backflow forces the valve closed. So in the event of downstream pressure surges backflow cannot contaminate the service fluids or cause damage to pipelines, process units and vessels upstream. The three BEL Valves designs are the swing check which ‘swings’ on a hinge off a seat to allow the forward flow and shuts under reverse flow conditions; the piston check which is also designed to prevent backflow but using a piston and damping mechanism; and the axial check which is a piston check with a streamlined, symmetrical and unrestricted flow path between the valve inner and outer body. Typical duties for check valves include chemical and additive injection, control solutions, isolation, system protection and use downstream from reciprocating pumps.
Benefits of BEL Valves swing and piston check valve design. Design and material choice are vital to ensure the longevity and lifetime performance of the simple swing check (non-return) valves. The disc is designed and manufactured as a one piece construction delivering superior properties in order to manage the severe shock duties sometimes experienced in service. The closing element, attached to the underside of the bonnet, is designed with durability and repeatability as a priority. With configurations that may be installed vertically or horizontally, designs can be provided with a counter-balance or torsion spring to reduce the valves tendency to stay open in situations where flow velocity changes slowly. For applications that require occasional flow in both directions the valve can be fitted with a manually operated lock open mechanism to hold the disc up and out of the flow.
Piston Check valves have a piston (or ball) that is guided and spring loaded so that as the upstream pressure varies the piston ‘floats’. Our dampening system is designed to avoid slamming in the event of sudden pressure surges, and under normal operating conditions when the flow eases the piston lowers to form a gas tight seal.
The Axial check design is also spring loaded but the ‘in line’ configuration results in limited pressure drop across the valve. This small, compact design is therefore a proven and reliable option for use in protecting rotating equipment.
Standard and Optional Features.
Materials, specification and approvals.
All of our check valve designs are in accordance with the relevant industry codes and standards including ISO 13628, ISO 14723, API 6DSS, API 17D and API 6AVI.