Page Category: Check Valves

Swing check valves have the option to install an external spring assist assembly. This spring is made from 316 stainless steel and is mounted external to the valve. When fluid pressure starts to drop, the spring retracts the swing arm and brings the disc back into the seat position. This effectively reduces the speed of the fluid flowing back towards the check valve, reducing the shock caused by water hammer. The spring returns the disc to the seat, but does not accommodate sealing. Hence, minimum backpressure requirements still apply for swing check valves with spring assists.

The lever and weight assembly for swing check valves achieve the same function as a spring assist. The exception is that the closing action is provided via a weight connected to the swing arm of the valve. Because lever and weight assemblies rely on gravity to provide their assistance on a closed stroke, they tend to work better in vertical installations.

Page Category: Check Valves

Wafer check valves have a solid thermoplastic body with a very thin “wafer” profile that makes them an ideal check valve for applications that require valves with short takeout lengths. Similar in operation to a swing check valve, the wafer check has a solid thermoplastic disc and seat arrangement that performs the check action. In one direction, fluid lifts the disc off of the seat and allows fluid to pass freely. In the opposite direction fluid drives the disc into the seat, creating a seal and preventing fluid from back flowing upstream. Because of its slim profile, wafer style checks are unlikely to clog, which makes them ideal for service lines with large debris or solids. Wafer check valves are used in applications where it is essential to ensure fluid flow passes in only one direction. Wafer check valves can be mounted in vertical or horizontal directions, with the only restriction being a minimum back-pressure required to properly seat the check valve. Spring assists and lever and weight mechanisms are available options to assist in closing the valve quicker to reduce water hammer concerns.

Page Category: Check Valves

Swing check valves have a solid thermoplastic body with a large “flapper” that seats against the body of the valve. Swing check valves offer a large fluid area with a removable bonnet that allows for the valve body to be cleaned out without removing the valve from the pipeline. This is beneficial for installations that may contain debris or other items that could potentially clog the valve. Check valves are used in applications where it is essential to ensure fluid flow passes in only one direction. Check valves can be mounted in vertical or horizontal directions, with the only restriction being a minimum back-pressure required to properly seat the check valve. Spring assists and lever and weight mechanisms are available options to assist in closing the valve quicker to reduce water hammer concerns.

EL-PVDF Swing Check Valve

Asahi/America also offers the EL-PVDF swing check valve option. The EL-PVDF swing check valve for use in electrolysis plants in high temperature sodium hypochlorite, chlorine gas, brine, and hydrofluoric acid applications. The purpose of the EL-PVDF material is to prevent the generation of blistering or cracking that can occur in conventional PVDF during electrolysis production. EL-PVDF has been designed to achieve 2-5 times the normal life expectancy when compared to conventional PVDF in electrolysis applications. EL-PVDF performs in the most severe working conditions. Valves that are continually exposed to near maximum material working temperature limits for extended periods of time, especially in the production of chlorine, are the intended application target. Typical applications include, chlorine manufacturers, steel pickling lines, and pulp and paper manufacturing.

Page Category: Check Valves

A ball check valve with a foot screen can be installed vertically or horizontally on the suction side of a pump. The foot valve is an optional ball check valve arrangement where a screen is fitted into the inlet end of a ball check valve. This screen is used to filter large debris and solids from a fluid to prevent damage to pumps, clogging of valves and to protect downstream instrumentation. Foot valves can be typically found anywhere there is a check valve used as an intake. This includes pump inlets, lift stations and drains.

Page Category: Check Valves

The Asahi/America ball check valve employs a free moving ball, which unseats to permit flow in one direction, but seals against a seat to prevent backflow. It may be installed vertically or horizontally. Also available as foot valve for suction side of pump.