Industrial Valve Supplier

What Are Industrial Valves?

In industrial applications, valves play a vital role in controlling or regulating media movement in piping systems. The wide scope of industrial applications allows more varieties in valve design.

While most are for the stop-start mechanism, certain valves also have throttling capabilities. Additionally, valves are either manually operated or with the use of a gear that moves the actuator.

Any person engaging in the piping business should understand the importance of valves. Knowing the operation and maintenance of valves ensures that these can last longer. It also ensures that the entire piping process is without delays.

This article discusses everything you need to know about industrial valves. Included in this article are the different valve functions and the general valve parts. This article also discusses the commonly used valves in industrial applications.

Valve Functions

Valves play a pivotal role within the piping system, and each valve has a different role to play. To summarize, there are five functions for industrial valves. While it is possible that there are overlapping functions for one type. Commonly, most are more efficient in just one or two functions at a time.

• Stop & Start

  Valve either allows media to pass or obstructs media flow so it won’t pass.

• Fluid Flow Control

  The valve controls the media flow. Valves that have this function can be multidirectional. These are also multiports, meaning, they have more than exit points. Such characteristics allow the media to move in different directions.

• Pressure & Flow Regulation

  Through the opening and closing, valves can adjust or maintain the pressure and flow within the pipes.

• Pressure & Vacuum Relief

  Valves can relieve over-pressure, especially when there is media flow. It can also increase pressure when vacuum is present.

• Throttling

  Some valves allow partial opening so a certain percentage of media can flow through.

Valve Parts

The industrial valve is a collective set of smaller parts. There are internal and external parts. While specific valve types contain certain components definitive to that design, all industrial valves share major valve components. This section will discuss the different valve parts.

Take a look at a cross-section of a valve below to view the major components:

Body

The body houses the internal parts of the valve, including the trim. This is also the passageway for the fluid. Industrial valve manufacturers produce this as either of the three: cast, forged or fabricated. The body also connects the valve on both ends to the pipe system.

The body valve designs depend on the valve functions as well as the size of the pipes to which the valve attaches. That being said, there are three major types:

Bonnet

Some industrial valve manufacturers call this part as the cover. There is much emphasis on the bonnet and body connection because the majority of leaks come from this. Split body ball valves don’t have a bonnet as the body is cut into half lengthwise.

The two functions of the bonnet are:

It houses the internal parts of the valves.

It supports the stem since it is in the of the bonnet in many valve types.

Valve Trim

The valve trim refers to the collective valve parts that come in contact with the flow media. These are the disc, the valve seat, and stem. Take note, some valves may have additional parts, but generally speaking, these three are always present in most valves.

The type of seat and disc, along with the placement of the disc in relation to the seat, determine the valve trim performance. It is also the combination of the disc, seat, and stem that determines the movement and control of the valve.

• Disc

  The disc has alternative names depending on the type of valve. Ball and gate are two other names for the disc. This part can function as a throttle or to stop/permit the flow of media into the valve to the pipes.

• Seat

  The seat provides the cushion for the disc. Seal rings are its other name. Some types of valves have one seat while others have two or more.

  The higher the number of seats, the better sealing. Multiport valves have more seats since these have more than one exit. Some seats are integrated into the valve structure. Others are replaceable.

  The quality of the valve seat directly affects the effectiveness of leakage prevention. Depending on the requirements like the type of flow media, temperature and pressure gauges, and the likes, valves are either elastomer like Teflon or metal.

• Stem

  The stem is the shaft that connects the disc to the actuator. This part supplies the motion needed to open or close the disc. The opening and closing movements are either linear like the gate or globe valves, or rotational like the butterfly and ball valves.

Bolts

Bolts hold one valve part to another, for example, the bonnet to the body. The bolts make the seal tighter.

Actuator

The actuator goes by many names such as wheels, levers, and handles. More often than not, the names follow the design of the actuator. Gate and globe valves have manual handwheels as actuators. On the other hand, ball, plug and butterfly valves have levers that act as actuators.

While manual actuators are common, there circumstances that automation or power is the ideal way to actuate.

There are issues with valve location such as being remote.

Time does not allow the valves to open quickly via manual methods.

The valve is large and the pressure is too high; manual opening becomes risky.

Packing

This is also called the gasket. Packing functions as a seal between the stem and the bonnet. This plays an important role as the proper installation of the packing increases the life service of the valve.

Installed too loose, the valve leaks. Installed too tight, the valve cannot move. Packing, in other words, reduces damage and increases the sealing capability of the valve. It has five components, namely the gland follower, the gland, the stuffing box, and the backseat.

Yoke

The yoke is the arm that connects the body and bonnet to the actuator. Made as a one-piece with the bonnet, the yoke should withstand the force applied to the actuator. The yoke contains the nuts and bushing that act as connectors to other parts of the valve.

Types of Valves

There are nine major types of valves on the market. Below is a table that shows these valve types and their matching functions. To learn more about each valve, read our 9 Types of Industrial Valves guide that explains the different types in detail.

Valve Manufacturing Methods

There are three methods of making valves: cast, fabricated, and forged. This section will list compare the advantages and disadvantages of each method. To learn more about what takes place in each stage of valve production, read our Industrial Valve Manufacturing Process guide.

Cast Valve

The casting method starts by melting the metal material and pouring this into molds. The liquid material solidifies in the molds and then removed and polished.

Fabricated Valve

Fabrication is the process of cutting, forming, drilling or any type of machining and welding metal materials into finished products such as valves.

Forged Valve

Forging is the method of changing the shape of solid metal using thermal or mechanical energy-driven tools.

Valve Opening & Closing

There are three ways of opening and closing the valve: linear, rotational and quarter turn. Check out the table below that shows the valves and the methods of opening or closing:

Here is a video of a gate valve opening and closing. Gate valves belong to the linear motion valves.

The upward and downward movement of the disc either closes, opens or throttles the media flowing. Because of the thread design of these types of valves, opening and closing of the valve is slower compared to the other two types.

On the other hand, the butterfly valves is a rotational type as seen in this video.

A rotational valve type has a hinge pin that holds the disc. Once the hinge pin releases the valve, it closes the entry point. Turning the actuator in the other direction tightens the pins. This, in turn, raises the disc to allow media to enter the valve.

Meanwhile, ball valves are quarter-turn motion valves. Here is a video of a ball valve opening and closing.

A quarter-turn or 90°-turn valve only needs that much angle to open or close the valve. Compared to the linear and rotational types, this has a much faster mechanism.

Valve Actuators

Look at the different valve actuation types.

There are three major types of actuation operation: manual, power and automation.

Manual

Manual actuation means the actuator can be opened or closed by hands. Manually driven actuators are the best choices when there is flexibility in positioning the valves. Also, this is the best option when power is too far off to reach the valves along the pipeline.

Manual actuators are not the best choices when the valve is too big. However, hammer or gear heads can aid the actuator if used in larger applications.

Power

Actuators use different power methods for the opening and closing of the valve.

Automation

Automatic actuators do not use external force to open the valves. Rather, it uses internal fluid or gas pressure.

Valve Stems

The valve stem receives the actuator motion so that the valve can open, close or throttle. There are five types of valve stems based on the orientation of the thread, as well as the movement of the stem.

Rotary Stem

Quarter-turn valves such as the butterfly valve, plug valves as well as the ball valves have this kind of stem. For the valve to open, the stem only needs to turn a quarter.

Sliding Stem

Contrary to the other stems in this list, the stem does not rotate. Rather, it slides to open or close the valve. Applications that need fast opening require this stem design. Control valves with pneumatic and hydraulic actuators are such examples.

Non-Rising Stem

The non-rising stem has its threads inside the valve. As its name connotes, the stem becomes stationary. Opening and closing of the valves mean the valve disc travels up or down in rotation along the stem.

The design exposes the stem to the media when the valve is open. That being said, the media also impacts the stem. In connection with this, two issues arise: how the design affects stem durability, and how the design affects pressure levels.

Non-rising stems are used when there is more linear movement, given the limited valve and pipe diameter.

Rising Stem with Inside Screw

Similar to the previous type, the thread is also inside the body. The stem exposed to the external environment is smooth. However, in contrast, rotation makes the stem and actuator rise to open and down to close. Once the stem rises, the body exposes the threads to the media. This can cause erosion to the threads, creating leaks over time.

Rising Stem with Outside Screw

This design, more popularly known as OS & Y, is similar to the previous design as the stem rises once the valve opens and vice versa. However, the difference is that the thread is in the exposed part of the stem. The one in contact with the valve is smooth.

The rising of the thread can be one of the two designs:

1. The stem has an attached handwheel that goes up together for opening the valve.

2. The handwheel rotates and the stem rises alone.

Valve End Connections

Valve end connections refer to the connection of the valve to the pipe system. There are five types of these connections. Check this video below to understand more about valve ends.

Threaded

The threaded type needs also to have the corresponding thread in the pipes so they fit together. The valve end has the female thread and the pipe end, the male thread.

Both ends must follow the same standards. Take note, though, there are several standards available the National Pipe Thread Tapered (NPT), the British Standard Pipe Taper Threads (BSPT) and the British Standard Parallel Pipe Threads (BSPP) .

The threaded type can be one of two types: the straight threaded and the tapered threaded. The straight threaded ends have a soft seal like an O-ring or a washer placed between the pipe and valve connections. On the other hand, the tapered threaded type does not have that soft seal.

Flanged

Flanged-end valves are easy to install and remove. This connection uses bolts to connect the valve to the pipeline. A gasket is installed between the two connections to ensure a tight seal.

Flanged connections have several industrial standards to follow. Examples are ANSI/ASME or the American National Standards Institute and American Society of Mechanical Engineers, respectively. There is another standard that industrial valve manufacturers follow called DIN, when translated to English it means German Institute for Industrialization.

Butt-Welded

The outer edges of the pipe and valve when stacked together create a bevel or valley. This is where the welding is done. The bevelling creates a more uniformed thickness to the pipe-valve connection. Often done on steel pipes and valves, pipes with this type of valve can endure high pressure and temperature.

Socket-Welded

The valve has a wider diameter than the pipe diameter so the pipe is inserted into the valve. Closing of the rim is done by welding it. This type of connection is permanently closed and leak free.

Media-Valve Relationship

Media is the material that flows through the valve. It directly affects the valve and disc material. The speed of the flow correlates to high pressure and temperature. That being said, there are certain media types that are not suitable for a particular valve. Check the table below:

Considerations When Buying Valves

There are many factors to consider when buying industrial valves.

Purpose

What is the purpose of the valve? Is it for throttling or control? Is it for start-stop operations?

Media

The media that flows through the valve greatly affects the lifespan of the valve. Furthermore, the wrong kind of media may cause damage to the valve. Some media are corrosive, others are abrasive.

Some have high-pressure levels while others have low temperatures. Knowing the media and how it works with the valve material is an important consideration.

Actuation

Whether manual actuation is the best option or not, actuation is also a factor worth considering. Process pipelines require large valves. Manual actuation is not suited for a large valve. Instead, use pneumatic or automated valves.

Material of Construction

The valve body material is important because it should suit the right media. Choosing the wrong kind of material means shorter valve lifespan.

For example, use corrosion-resistant materials if the media is acidic. High-pressure media uses valves made of an alloy that can resist high temperature and pressure levels.

Valve Type

Certain actuators work well with particular valves. For example, the ball valves often have the quarter turn movement so the best actuator is a rotary or quarter turn. It does not need the lever type because it does not move up or down to open or close the valve.

Valves can either perform one or two actions such as shut off, divert the flow, pressure relief, mix flow and adjust the flow.

Pipe Considerations

The valve diameter with the same size as the pipes can withstand high pressure. But when the valve diameter is smaller than the pipe’s, there is the tendency for the valve to bend. The bending may cause external and internal leakage.

End Connections

The end connections of the valves often follow that of the pipe. Having said that, compatibility is of the two is vital. A flanged end valve is not the required one when the pipe employs a thread.

Industry Standards

Valves follow certain standards. With that in mind, there are standards for the material of the valve. There are standards for the end connections. It is important that valves follow the rigid regulations imposed by international bodies. This ensures safety and proper valve installation.

Valve Supplier

The valve supplier is the point of contact when thinking of buying industrial valves. The valve supplier should provide the customer with the right valve manufacturer.

The former is responsible for informing the customer about the industry standards and other considerations. He should be able to provide the right product with the right price point. He should also aware of customer needs, the right type of valve for a particular industrial application.