valves

1. ALL ABOUT BALL VALVES
Page 1
Ball valves are mechanical devices that are used to restrict or allow the
passage of a fluid (liquid or gas) in a piping system. They are known as
quarter-turn valves because a 90 rotation of the handle is all that is required
to change the valve position from fully open to fully closed or vice versa. This
quick quarter-turn movement on ball valves contrasts with the multiple 360
turns needed on other valve types such as gate or globe valves.
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The term ball valve refers to the fact that the internal mechanism that is used
to change the flow through the device is a spherical ball that has a hole
drilled through it which serves as the valve’s flow control. Ball valves are
known for their overall durability and long service life, as well as for their
reliable sealing and are therefore often preferred as a choice for shut-off
applications.
ALL ABOUT BALL VALVES
They are especially capable of tolerating contaminated media, more so than
other valve types. In most instances, they are not used for precise regulation
of flow as there are other valve designs such as needle valves that allow for
finer metering of flow rate. There are some special designs that permit some
degree of flow regulation.

2. ALL ABOUT BALL VALVES
Page 2
This article will present information about ball valves including, their
construction, the different types, applications, and key specifications. To learn
more about other types of valves, refer to our related guide Understanding
Valves.
BALL VALVE CONSTRUCTION
The primary components used in the construction of a ball valve are the:
Valve body
Ball flow control
Valve seats
Valve stem
Packing
Bonnet
Actuator
VALVEBODY:
The valve body is the main assembly that serves as the pressure vessel and
into which the other ball valve components are assembled. Valve bodies are
fabricated out of several different material types, common ones being steel,
brass, bronze, cast iron, stainless steel, aluminum, PVC, or CPVC. The valve
body can be fabricated as a single piece or two or more pieces that are
assembled using bolts. Multi-piece designs can be disassembled for repair
whereas single-piece designs are not intended to be repaired and require the
valve to be changed out in the event of a failure.
BALL FLOW CONTROL:
The ball is the flow control mechanism of the ball valve and is a sphere
through which a hole or tunnel has been drilled to allow fluid to pass through
it when it is oriented with the hole in line with the fluid flow direction.

3. ALL ABOUT BALL VALVES
Page 3
Reduce bore designs are common in most ball valves and are usually one-
piece bodies. Because the diameter of the bore in the ball is less than that of
the pipe ID, there are some friction losses incurred, but these are usually
smaller than with other types of valves.
Full bore
Reduced bore
V-port or slotted port
The tunnel or hole in the ball of a ball valve is characterized as being of one
of several types:
The ball is the flow control mechanism of the ball valve and is a sphere
through which a hole or tunnel has been drilled to allow fluid to pass through
it when it is oriented with the hole in line with the fluid flow direction. The ball
is attached to a stem that enables movement through 90 of rotation to open
or close the valve.
The ball can be of a floating design, meaning that the ball is floating in the
media and is sandwiched between the valve's seats which hold it in place.
The ball can drift within the cavity of the valve body under the natural
pressure of the fluid flow in the valve.
This slight movement of the ball causes it to press against the downstream
valve seat, creating a positive seal. Another design called a trunnion ball or
trunnion mount, provides support for the ball on the top and bottom, thereby
reducing the load on the valve seats. Trunnion ball valves are used for large
diameter valves or for operation conditions involving high pressures.
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Full bore designs have the diameter of the bore equal to that of the pipe. This
design reduces friction losses and facilitates easier cleanout, a process
referred to as pigging. These models do have larger housings and therefore
cost more than reduced bore designs.

4. ALL ABOUT BALL VALVES
Page 4
V-port ball valves are ones in which the ball that traditionally has a bore with
a circular cross-section is replaced by one that has a cross-section in the
shape of a “V”. These designs are available with interior angles of various
values, from 15 – 90 , and in some designs, the ball valve can be retrofitted
from a circular bore to a V-port design. The V-port ball is used in place of a
circular bore ball in high-flow rate applications where a minimal pressure drop
or tight shutoff is required. They are also used to provide a higher level of
flow control or rangeability and can approach a linear flow profile as a
function of actuator position, unlike circular bore designs which are highly
non-linear. With retrofitting, a shutoff valve can be repurposed into one that
functions as a flow control valve.
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VALVE SEATS
The valve seats seal against the ball and provide for a leak-free operation of
the valve. Seat material options include metals and fluoropolymers, and the
selection of a suitable valve seat material is driven by the operating
conditions (i.e. temperature, pressure, and the nature of the fluid being
passed through the ball valve, and desired operating torque, for example.)
Some common valve seat material options include:
PTFE (polytetrafluoroethylene)
Carbon-fiber-filled PTFE
Carbon
Metals
Ceramic
PEEK (Polyether ether ketone)
Acetal (Polyoxymethylene - POM)
UHMW (Ultra-high molecular weight polyethylene)
Ball valves that use flexible seat materials are called soft seat ball valves
versus metal seated ball valves. There are also graphite seated ball valves
available.

5. ALL ABOUT BALL VALVES
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VALVE STEM, PACKING, AND BONNET
The valve stem is a shaft that connects to the ball and extends out through
the valve body where it is connected to the actuation mechanism for the
valve. Surrounding the valve stem is packing material, which seals the valve
stem and prevents the fluid or media from seeping through the opening in the
valve body. O-rings are also used to seal the valve and prevent leaks. Some
designs use a lubricant seal system. The portion of the valve body that
houses the stem and packing material is sometimes referred to as the valve
bonnet.
ACTUATOR
The valve actuator is the mechanism that controls the valve positioning from
open to closed. Ball valves can be manually actuated using a hand lever, or
they may be actuated mechanically or electrically. Mechanical actuation can
involve pneumatics or hydraulics. Electrical actuation usually involves a
and a reducing gear mechanism to slow the rotation speed of the actuator
and thereby prevent water hammer.
motor
TYPES OF BALL VALVES
There are several ways by which ball valves may be characterized. These
include by the material used in their fabrication (most typically the valve body
material), by the valve body construction, by the valve configuration, or by
some other parameter such as the fluid handled or nature of the internal
design features.
The types of ball valves characterized by the valve body material include:
Brass ball valves
Stainless steel ball valves
(includes PVC and other polymers such as
polypropylene and PVDF)
Plastic ball valves

6. ALL ABOUT BALL VALVES
Page 6
There are also 3-way and 4-way ball valves available. Three-way designs are
in an “L” or “T” configuration and can be used to distribute the fluid flow to
two different ports or to mix, blend, or divert flows. Figure 1 below illustrates
some possible flow configurations for a 3-way ball valve.
Figure 1 - An illustration of T and L port configurations on a 3-way ball valve.
The valve configuration is also a method of characterizing ball valves. The
most common valve configuration is an inline configuration, where the valve
body sits directly in the pathway of the piping system and has 2 ports, called
a 2-way ball valve. These are used for shutoff service.
Split-body ball valves
Top-entry ball valves
End-entry ball valves
One-piece ball valves
Two-piece ball valves
Three-piece ball valves
Looked at from the perspective of valve body construction, the types of ball
valves include:
Bronze ball valves
Cast iron ball valves
Steel ball valves

7. ALL ABOUT BALL VALVES
Page 7
A 4-way ball valve would have 4 ports located on the valve body and has
similar capability to the 3-way ball valve. Some designs use bolted on ends
and allow for reconfiguration of valve ports to function as inlets and/or block
flow ports.
Some other methods of characterization for ball valves include by the fluid
they are designed to handle or some specific design feature. Examples of
these include hydraulic ball valves, which are suitable for use in hydraulic
circuits and similar applications that require high pressure.
Lined ball valves feature a non-reactive coating or lining that has been added
to the interior surfaces of the valve body. The addition of this lining protects
the valve from exposure to caustic or corrosive chemicals, improves the flow
coefficient of the valve by reducing friction, and prevents potential
contamination of the fluid flowing through the valve.
SPECIFICATIONS & ATTRIBUTES
Ball valves are specified by several key parameters and attributes that are
summarized below. There can be some differences in these specifications
across manufacturers or suppliers, so this information should be used as
general knowledge and will help to prepare for engagement with suppliers.
Valve body material – the material from which the valve body or housing
is fabricated, such as stainless steel, PVC, PVDF, brass, or bronze.
Number of ports – the porting design of the valve, such as 2-way, 3-way,
or 4-way.
Ball material – the material from which the flow control ball is
constructed. Common material options include brass, stainless steel,
chrome-plated, or plastic.
Body style or type – reflects the design style of the housing as a single
piece or multi-piece design.
Valve shape – represents the valve shape as being inline, L, T, or Y
.

8. ALL ABOUT BALL VALVES
Page 8
Pipe size – the diameter of the pipe into which the valve is being fitted.
Common ball valves sizes align with pipe sizes to facilitate ease in
sizing and installation.
Port style – reflect the port design and ball bore such as full bore,
reduced bore, or V-port.
Connection type – represents the desired port connection fitting style for
the valve. Common options included threaded, flanged, solder connect,
and socket weld, or socket connect union.
Gender – identifies whether the connection type is male or female.
Thread type – for threaded valve connections, reflects the thread type
on the valve port such as NPT, UNF, NPTF, BSPT, etc.
Seat material – the material from which the valve seat is fabricated,
such as metal, ceramic, or a soft seat such as a fluoropolymer.
Seal material – the materials used in the valve seal.
Flow rate or flow coefficient – a measure of the ability of the valve to
pass fluid, in units of volume per unit time. Sometimes, flow rate is
expressed as a flow coefficient, Cv, which is defined as the number of
U.S. gallons of water @ 60 F that can pass through the valve per
minute at a pressure drop of 1 psi.
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Maximum rated pressure or pressure range – establishes the safe range
of operating pressure for the valve. This value may also reflect operating
temperature.
Media or fluid application – indicates the type of liquid or gas to which
the valve will be exposed, such as water, natural gas, fuel oil, air,
hydraulic oil, food, solvents, etc. The nature of the media and its
properties will determine the suitable materials for the valve body, seals,
seats, ball, and other components.

9. ALL ABOUT BALL VALVES
Page 9
Ball valves are used in many different industries. Some of these include
chemical, oil & gas, pharmaceutical, food processing, HVAC, sanitary
applications, and others such as corrosive media and cryogenics. Many
manufacturing processes use ball valves, and they are widely used in
residential settings as well. They can effectively function with a full range of
media, including liquids, gases, chemicals, potable water, fuels, and food and
beverages, provided that the material selection for the valve components was
done with the type of media in mind.
One ball valve limitation is that when used in slurry applications, it is possible
for suspended particles to get trapped in the body cavities of the valves,
which can lead to premature wear, leaks, or valve failure necessitating
replacement. As stated at the beginning of this article, they are for the most
part best suited for shut-off service applications, although some designs such
as the V-ported ball valve have flow regulation capability.
BALL VALVE APPLICATIONS, ADVANTAGES, AND
LIMITATIONS
Actuation type – describes the means by which the ball valve will be
actuated, such as manual (handle or lever), hydraulic, pneumatic, or
electrical, for example.
Operating torque – the amount of torque needed to turn the valve
between the open and closed positions, measured in N-m or lbs-F.
Ball valves have many advantages. They are very easy to use, open and
close quickly, and are available in multi-port designs unlike some other valve
styles like globe or gate valves. They are also smaller and lighter than other
valve styles and can have a lower price point. They are reliable devices and
offer a long service life. Additionally, they can have lower operating torque
than other valves.