Other Types of Valves
Valves come in all shapes and sizes. In addition to the typical valves covered on the Valve Pipeline it is important to note that there are other valve types that exist. This page will provide a quick overview of some of the non-standard type valves.
Cryogenic valves are used in extreme low temperatures. Cryogenic valves are usually made out of full stainless with specialized elastomers to handle the cold temperatures. Cryogenic valves have an extended bonnet to move the operator away from the cold process that runs through the port of the valve. Cryogenic valves are typically ordered as per a certain specification; but can be tested to BS6364 (British cryogenic standard). The standard can be purchased here
Y-pattern valves are designed to support the full stress induced by the operating pressure. The design also offers increased flow through the valve over traditional globe and check valves.
Non-Slam Piston and Nozzle Check Valves
A non-slam piston check valve is equipped with a counterweight, or other mechanism (hydraulics), to control the closing time of the valve.
Nozzle check valves (commonly referred to as Noz-checks) have a spring-assisted disc which moves axially with a short displacement to open. The design works to give a streamlined flow path with a venturi effect through the valve, resulting in a low pressure drop. When flow is reduced the disc reacts immediately limiting back-flow. The spring-load, low mass disc and short displacement results in a quick response.
Both of these check valve designs are non-slam meaning they are specifically designed for fast-reversing systems where back-flow is a constant concern. Non-slam valves work to minimize water hammer damage, minimize pressure loss, and protect rotating equipment from damage due to flow reversal.
Contact - The Valve Pipeline
Check valves have a "cracking pressure" or a minimum upstream pressure at which the valve will operate.