What Is A Gate Valve’s Mechanism And Working

Home What Is A Gate Valve’s Mechanism And Working
07/09/2022
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Types Of Gate Valves
Source: Dombor

What Is A Gate Valve?

dombor Gate Valve
Source: Dombor

Gate valves are essentially a part of the industrial valve family that is created to control the flow of fluids linearly. These valves can allow or restrict the flow of gasses in both directions. It mimics a wedge-shaped disk and is responsible for pouring slurry or any other medium with thick particles. However, the gate can face parallelly, though it is relatively uncommon due to lack of pressure (shown in the former setting).

A gate valve is also called a sluice valve due to the above-mentioned cutting-through mechanism. This valve works through a barrier (or a gate) to allow the fluid to flow, hence the name. Also, the on-and-off action it provides through this shape makes the flow more automatic. They are also capable of throttling to a limited extent, but doing so is not promoted by many gate valve supplier companies and professionals in the area. This is due to the gate’s capacity to cause damage.

The next step is to know the components that make up a gate valve.

Parts Of A Gate Valve

Dombor Gate Valve
Source: Dombor

Typical gate valves are stem-threaded to the actuating motor. These stems can be rising as well as non-rising depending on the ends. While rising ones are threaded to the gate, the non-rising ones are connected to the handwheel actuator. This system acts as an optical indicator. There is a general turf between a gate valve vs. ball valve. Knowing the components can create an understanding of the difference between a gate valve and ball valve.

In this instance, we will be looking at a general gate valve. Although there are a lot of parts in detail, they can typically be categorized into seven components. They are as follows:

  • The Main Body:

The body encompasses the internal components of the industrial gate valve. The part connected to the pipe or duct system constitutes the covering of all the other parts of a gate valve. The main body comprises flanged ends drilled in a manner compatible with the pipe system and its dimensional measurements. They are typically cast or welded from materials like ductile or cast iron, carbon steel, and alloy steel. This body is highly vacuumed to ensure directional control.

  • Stem:

As mentioned earlier, the stem is threaded either to an actuator or the gate, depending on whether it is a rising or non-rising gate valve. The wedge-shaped disc is controlled through the stem and ensures proper positioning during up and down movements. This component can be classified as a rising and non-rising design, depending on whether the stem is stationary or dynamic. Rotation of the stem for opening and closure makes the wedge-shaped did travel on the stem. This exposes the fluid medium to the stem end. 

  • Packing:

This is essentially the gasket of the gate valve. Packing material creates an additional vacuum between the stem threading and the main body. They are typically constructed with a material having elastic properties, such as an elastomeric one. The role of this component is crucial for the proper flow of viscous and dense fluids. Creating an air-tight condition in the body will ensure smoother movement. An excellent industrial gate valve manufacturer would never miss this component ever.

  • Bonnet:

Not one component is more essential than the other. The bonnet sits on top of the main body, allowing the stemming thread to pass through. The role of a bonnet is to essentially guide the stem and connect the disc to the automator. They prevent leakage and form the closure for the main body. It also gives the body added strength.

This is further divided into four types:

Screw-in Type: Utilizes sealing pressure; this type makes maintenance and cleaning a simple and easy process. Screw-ins are the best in terms of simplicity of design and durability. It forms a tremendous air-tight vacuum seal to the main body, allowing not an ounce of air inside.

Bolted Type: Suitable for applications involving a high degree of pressure.

Union Bonnet: They are incredibly great for easy maintenance and cleaning inspections. It is no exaggeration to say that they are the favorites for technicians working in the plant. 

Pressure seal bonnets:

Another essential type that does not fall into any of the above categories is the pressure seal bonnets. They are excellent for pressures exceeding 2250psi (or 15 MPa Units). They are widely used due to their extreme pressure sustenance abilities. The unique characteristic that sets this bonnet apart from the rest is its downward cup figure. The increasing internal pressure in the  industrial gate valve forces the cup upward, which tightens the seal even more. Through this mechanism, leakages from the closures are prevented.

  • Gate:

As in the name, the gate is a barrier in the form of a wedge shape. This is the opening through which the fluid flows. This is again classified into two kinds:

Solid Wedge: Primarily used in shutoff applications, it is a solid metal piece that makes the wedge flexible and cuts the perimeter to modify the angles.

Split Wedge: While a solid wedge is made of a single piece, a split wedge splits the metal into two solid pieces, which enclose the seats. This is extensively used when the fluid is corrosive at an average temperature.

  • Seat:

Seats are responsible for providing a basis of arrangement for the gate valve. They are also made of elastomeric substances and are two in number, located on either side of the valve. They can be incorporated in two ways: by constructing them internally within the body or by creating separate ring-like structures threaded with the stem mentioned earlier. They can also be welded in conditions where threading is not feasible.

  • Actuator:

Last but not least, the valve uses an actuator that is responsible for activation. When the torque forces are high, vital gear such as motors may have to replace the actuator. Common examples of an actuator are handwheels and motors. This component also makes use of Van Der Waal forces. They are fixed by nuts and bold and indicate the status of the wall entrance. Actuators are ordinarily available with markings that indicate the direction for opening and closing.

Now that the components of a generic gate valve are familiar, we will move further by analyzing the processes and mechanisms that make the fluid flow with control.

How Does A Gate Valve Work?

Working Of A Gate Valve
Source: Dombor

The process it undergoes is not that difficult to understand. Although there was a lot of exposure to categories and classifications, the design is fundamentally similar, and their working remains constant. Here, the mechanism is divided into smaller parts for crystal-clear understanding and is discussed under:

Closure: Closing and opening are as vital as they are easy to understand. All there is to it is rotating the actuator (handwheel, in this case) in a clockwise fashion. The stem and the gate move downwards, facing the seat upon rotation. This closes the barrier component and restricts fluid flow in any direction. The barrier closes it entirely and prevents leakage and wastage of fluids. This becomes easier in a china electric knife gate valve type.

Opening: Subsequently, rotating the actuator in the opposite direction opens the barrier and allows the movement of gasses and liquids through the main body. Be mindful of not applying excess pressure because this can break the internal components like the stem and the disc. Pressure must be kept to a minimum to avoid leakage.

Back-up Plan: But what happens when there is too much pressure? Go to the packing nut on the main body of the gate valve and loosen it by a single turn. This will allow air to flow and control the pressure within the internal components. After the flow is completed, remember to close it again to prevent leakage.

Throttle: Open the gate valve partially. To master throttling, one must be mindful of the pressure build-up of the medium. This has the potential to damage the wedge. Back-flow is very much recommended as this would lessen the friction responsible for the damage. 

What Is A Gate Valve Used For?

Gate Valve Industries
Source: Dombor

The best pneumatic gate valve manufacturer can deliver gate valves which are very much versatile. Gate valves are used in the following places:

  • Food industries
  • Pharmaceutical and medicine industry
  • Hydrocarbon industries
  • Feedwater industries
  • Steam uses
  • Slurry uses
  • Power production
  • Petrochemical and Refinery

Conclusion

Gate valves are uncomplicated machines that are used in multiple industries. Their versatility makes them one of the best among all industrial valves. Fluids include liquids and gasses, and they are to flow at random. Industrial gate valves are a necessity in most industrial settings. Valves can control these fluid movements in a single direction. It does not need a spacious setting compared to other industrial valves. The essential factor for the valve’s working is the presence of pressure on the sealing surface, which is best achieved in a wedge format.Dombor is one of the best China valves manufacturers, contact us and order gate valves right now!

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