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.
Design Ranges of Materials
KATA cast steel check valves are designed and manufactured to
provide maximum service life and dependability. All check valves
meet the design requirements of American Petroleum Institute
standard API600 & 6D.BS EN 13709 and generally conform to
American Society of Mechanical Engineers standard ASME B16.34.
Valves are available in a complete range of body/cover materials
and trims. Standard body/cover materials include nine grades of
carbon, low alloy and stainless steels, for special applications
they can be supplied in other grades of alloy and stainless steel,
there's a full range of trim materials to match any service
optional packing and gasket materials are available for a full
range of service conditions.
Available Modifications For KATA Steel Valves
End connection modifications
Packing and gasket changes
Handwheel extensions Pressure equalizing
Customer specified coatings
Weld end bore changes
Oxygen & chlorine cleaning & packaging
For 150Lb-8",300Lb-8", 600Lb-6",900Lb/1500Lb/ 2500Lb-4" & over.
Bolted cover. welded cover and pressure seal bonnet in services
requiring frequent cycling or with high pressure/temperature
variations. C)End Connections
A choice of flanged, RTJ flanged or buttwelding end for piping
A male and female joint or tongue and groove joint is used 150Lb to
600Lb valves. Ring joint is used in the body to cover connection in
900Lb & higher rated valve. E)Outside Lever And Weight
All external hinge pin swing check valves 12" and smaller are
available with an optional outside lever and weight, internal hinge
available with all swing check valves. F)Seat Rings
Separate heavy duty, full ported rings for easy maintenance.
Screwed or welded connectioninto body.
G)HCU weighted mechanical accumulator
This design can be used to either dampen or assist closing of the
check valve disc depending on orientation. by using the hydraulic
control unit to buffer action the disc, the valve opens at lower
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