The most adaptable and commonly used types of control valves are sliding-stem globe and angle valves. Their robust construction and the multiple features make them suitable for a variety of process applications, including rigorous use.

BALL BODIES

Ball valve bodies categories are as follows:

Angle valves

• Cage-style valve bodies
• Disk-stack style valve bodies
• Angle seat piston valves
• Globe valves
• Single-port valve bodies
• Balanced-plug cage-style valve bodies
• High capacity, cage-guided valve bodies
• Port-guided single-port valve bodies
• Double-ported valve bodies
• Three-way valve bodies.

Rotary valves

• Butterfly valve bodies
• V-notch ball control valve bodies
• Eccentric-disk control valve bodies
• Eccentric-plug control valve bodies

BUTTERFLY BODIES

Butterfly valves are valves with a circular body and a rotating motion disk closure part, which is a stem will support on a pivotal system. They throttling valves and are used to control flow of liquid in a piping system and to regulate the flow. This type of valve belongs to a group of valves called quarter-turn valves. The valve is comparable in action of a ball valve. Revolving the handle turns the plate parallel or perpendicular to the flow. It is a common design that is also very popular.

The flow controlling part in this system usually takes the form of ‘disk‘called a "butterfly which is fixed to the center of the pipe and mounted on a rod connected to an actuator which is situated on the outside of the valve. Turning the actuator positions the disc to either restrict or allow the flow of the liquid through the pipe depending on the angle of the valve. A seal comes into contact with the seat when complete closure is achieved completely blocking off the flow. The valve may also be opened a little at a time to choke the flow of liquid or fully to allow unrestricted flow of the fluid.

Butterfly valves have a triple offset design known as TOTS which prevents friction between the metal seat and the metal seal.

Butterfly valves are designed and manufactured for different pressures and uses. One particular type of butterfly valve is hard-wearing as it takes advantage of the elasticity of rubber but it has one of the lowest pressure ratings whereas another type which is used in higher pressure situations has the disc is positioned differently thereby increasing the valve's closing ability and improving its durability.

The tri-centric butterfly valve is a valve which has been adapted for high-pressure systems. It has a metal seat which enables it to withstand higher pressure.

Resilient butterfly valves have a flexible rubber seat and an optimum working pressure of 232 psi.

High performance butterfly valves have an optimum working pressure up to 725 psi.

Tri-centric butterfly valves usually have a metal seat conception and have a working pressure up to 1450 psi.

The ‘wafer style’ butterfly valve is designed to retain a seal against two-way pressure to prevent backflow in systems that are designed for one direction flows. It achieves this by using an accurately machined flat valve and a tight fitting seal such as a gasket and o-ring.

Lug-style butterfly valves have threaded inserts on both sides of the valve body which allows them to be fitted into place between two flanges using a separate set of bolts for each flange. This arrangement allows either side of the system to be disconnected without impairing the other side. A ‘lug-style’ butterfly valve which is used in dead end service usually has a reduced pressure rating depending on how it is mounted. If it is mounted between two flanges it could achieve a pressure rating of 150 psi but if mounted with one flange a pressure rating of just 75 psi may only be achievable in dead end service.

TRUNNION BODIES

A trunnion ball valve uses mechanical means of attaching the ball at the top and the bottom. This design is typically applied on larger and higher pressure valves. Trunnion balls come in various styles such as:

• Two-piece ball and stems
• Segment balls
• Three-way and Four-way balls
• Stem balls
• Custom valve balls

Materials from which they are manufactured include:

• Stainless Steel
• Steel

CHECK VALVE BODIES

A check valve permits fluid, liquid or gas to flow through it in just one direction.

A ball check valve is a check valve whereby the closing member (the changeable part that blocks the flow) is a sphere-shaped ball. In some ball check valves, the ball is spring-loaded to assist in keeping it shut. For those types that do not have springs, a reverse flow mechanism is necessary to guide the ball toward the seat and create a seal. The internal surfaces of the main seats of ball check valves are narrowed to direct the ball into the seat. This will create a positive seal when stopping the reverse flow.

Ball check valves are commonly small, straightforward, and cheap. They are mainly used for their solidity and tolerance to chemicals in high pressure pumps that are used in several industries like the Oil refining, Petroleum, Natural gas production and Refining industries. The valves are made to be expendable and can endure high pressure. They can be fitted in a small plastic body that lines a metal housing which is screwed into the pump head.

There are other similar check valves where the disc is not a ball, such as poppet valves which are forced by a spring. Ball check valves are not like, ball valves which have an adjustable rotor to stop or direct flow. Check valves are two-port valves as they have two apertures in the body of the valve, one for the fluid to enter and the other for it to exit the chamber. There are various types of check valves used in a wide ranging assortment of applications. Check valves are usually very small, straightforward and cheap and work automatically as most are not controlled by physical or external forces nor subject to any human intervention, so most do not have a valve handle or stem attached. The bodies of most check valves are made of plastic or metal, or metal alloy.

Check valves are designed for and consequently can be specified for a particular cracking pressure which is the smallest amount of pressure upsurge for which the valve will operate.

A fluid delivery check valve is comprised of: a valve body and a sleeve threaded on the valve body. The valve chamber is an inlet and an outlet port linked with the valve body forming an inlet and an outlet to the valve chamber. A valve seat is situated between the inlet and outlet ports. A spring-actuated plate shutter is located in the valve chamber and ring-shaped sealing gasket. The plate shutter has wing parts that are parallel to a central axis of the shutter. This reciprocates with an inner face of the chamber for assisting the opening and closing of the shutter. The valve seat reciprocates with the shutter through the gasket. The plate shutter comprises of a pair of steel sheet metal disks placed over each other and welded to each other, partially enclosing the ring-shaped sealing gasket.

Super check valves can be used with a wide range of pressures up to and beyond 400 psi and the low abrasion rate between the sealing components means that the valves have longevity and low maintenance requirements.

Check valves are easy to install because of their small dimensions. They are made from materials suitable for applications that use, liquids, gases, corrosive liquids, water, oil, diesel fuel, acids and other material found in many industries like the Oil refining, Petroleum, Natural gas production and Refining industries.

Types of check valves

• A closed ball check valve.
• An open ball check valve.
• A swing check valve is a butterfly-style check valve in which the disc, the part that blocks the stream, swings on a hinge or trunnion. It is either positioned onto the seat to block a reverse stream, or off seat to allow the stream to move forward. Swing check valves come in a variety of sizes. Large check valves are commonly swing check valves.