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.
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.
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
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
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.
also known as clack valves, one-way valves, or non-return
valves—for the oil, gas, and petrochemical industries. Check valves
are made so that fluid is only allowed to flow in one direction
through the valve – there are usually two openings within the
valve, one for the fluid to enter and one for the fluid to exit.
Our check valves are guaranteed to eliminate backflow issues and
allow liquid to safely flow in one direction. We offer a variety of
types of check valves suitable for a variety of applications often
related to the petrochemical industry.
Types of Check Valves
Piston check valves (also referred to as lift check valves), are
unique in that the higher pressure of an upstream fluid can cause
its disc (lift) to lift – allowing the fluid to flow to the
downstream side. (There is a guide that monitors the valve, so that
it can close accurately). Once the upstream high pressure is no
longer present, either gravity or higher downstream pressure will
bring the disc back down to close the valve, preventing a reverse
Ball check valves consist of a ball that moves to either block or
allow the fluid to flow through the valve. Sometimes a spring is
attached to the ball to keep the valve sealed shut. For valves
without a spring, reverse fluid flow is needed to move the ball in
order to close the valve.
Stop check valves do exactly what they say – stop fluid flow. They
are unique in that they can stop fluid flow regardless of the fluid
direction or pressure and they have the ability to close the valve
from an exterior switch – preventing any fluid flow.
Check Valve Configurations
Diaphragm check valves
Double ball check valves
Double check valves
Dual plate check valves
Swing check valves
Check Valve Materials
All of our check valves, which are hydro tested and come with a
one-year warranty, are listed below:
Cast steel construction
Stainless steel construction
Cast iron construction
Diameters from ½ to 36"
150 lb to 2,500 lb psi
we meet the check valve needs of suppliers to the petrochemical and
oil and gas industries throughout the world with fast delivery of
quality check valves at competitive prices. Our top priority is
providing affordable, high-quality valves as quickly as possible.
Applicable Standards: Design descriptions:
●STEEL CHECK VALVES, API 594/API 6D
●STEEL CHECK VALCES,ISO14313
●STEEL VALVES, ASME B16.34
●FACE TO FACE, ASME B16.10
●END FLANGES,ASME B16.5
●INSPECTION AND TEST, API 598/API 6D ●PSB,PRESSURE SEAL BONNET
●FLEXIBLE DISC, FULLY GUIDED
●RENEWABLE SEAT RINGS
●FLANGED OR BUTTWELDING ENDS