KATA VALVE API 6D CHECK VALVE NPS 2"~48"

A check valve allows fluid to flow through it in only one direction. Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem.

Design Features
Seat
For carbon steel check valves, the seat material is usually forged steel. The sealing surface of the seats is spray welded with hard alloy specified by the customer. Renewable threaded seats are used for NPS≤10 check valves, and welded-on seats are optional. Welded-on seats are used for NPS≥12 carbon steel gate valves. For stainless steel check valves, an integral seat is usually utilized, i.e. by welding hard alloy directly within body cavity. Threaded-in or welded-on seats are also optional for stainless steel check valves, if required.

Body-Cover Gasket

Stainless steel + flexible graphite wounded gaskets are used for Class 150 and Class 300 check valves; stainless steel flexible graphite wounded gaskets are used for Class 600 check valves, a ring type joint gasket is used for Class 900 check valves; a pressure seal design is used for Class 1500 and Class 2500 check valves

Body-Cover Connection
The body and bonnet of Class150 to Class 900 check valves are usually connected by with studs and nuts. And the body and bonnet of Class 1500 to Class 2500 check valves usually utilize a pressure seal design.

A check valve, clack valve, non-return valve or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction.

Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various types of check valves used in a wide variety of applications. Check valves are often part of common household items. Although they are available in a wide range of sizes and costs, check valves generally are very small, simple, or inexpensive. Check valves work automatically and most are not controlled by a person or any external control; accordingly, most do not have any valve handle or stem. The bodies (external shells) of most check valves are made of plastic or metal.

An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. Typically the check valve is designed for and can therefore be specified for a specific cracking pressure.

Heart valves are essentially inlet and outlet check valves for the heart ventricles, since the ventricles act as pumps.