What type of valve is used for throttling

This vibration can also affect the seat. Considered as one of the simplest designs, the pinch valve has a soft elastomer liner. It is pinched to close using fluid pressure. Hence, its name. Belonging to the linear motion family, the pinch valve is lightweight and easy to maintain.

Pinch valves are very effective when sterility and sanitation are the priorities. The elastomer liner protects the metal parts of the valve. The stem attaches to the compressor which is lined exactly above the liner. The pinch valve closes when the compressor lowers to the liner. This is due to the soft liner and smooth walls. This can cause tears in the elastomer liner. This valve is not suitable for gas media, and high pressure and temperature applications. The diaphragm valve is quite similar to the pinch valve.

However, its throttling device is an elastomer diaphragm instead of an elastomer liner. You can check how diaphragm valves work in this video. In the pinch valve, the compressor lowers into the liner and then pinches it to stop the media flow.

In the diaphragm valve, a diaphragm disk presses against the bottom of the valve to close it. Such a design allows larger particles to move through the valve. Between the straight through diaphragm valve and the weir type diaphragm valve, the latter is better for throttling. Although it can provide a non-leak proof seal, diaphragm valves can only withstand moderate temperature and pressure range.

Additionally, it cannot be used in multi-turn operations. The needle valve is similar to globe valves. Instead of a globe-like disk, the needle valve has a needle-like disk. This is more suitable for applications that need precise regulation. Additionally, needle valves are better valve control regulators for smaller quantities. The fluid goes in a straight line but turns 90 0 if the valve is opening. Because of that 90 0 design, some parts of the disk passes through the seat opening before a complete close.

You can view the pinch valve 3D animation here. The needle valves are for delicate industrial applications. That being said, thicker and viscous media are unsuitable for needle valves. The opening of this valve is small and particles in slurries become trapped in the cavity. Each type of throttling valve has its advantages and limitations.

Understanding the purpose of implementing throttling valve always narrows down the choices for the right kind of throttling valve. The right valve size means doing away with future valve issues. For example, a valve too large means limited throttling capacity. Most probably, it would be near its closed position. This makes the valve more prone to vibrations and erosion.

Furthermore, the valve that is too big would have additional fittings as an adjustment to the pipes. The fittings are costly. The valve body material is an important aspect when choosing the throttling valve. It should be compatible with the type of material that would pass through. For example, chemical-based media should pass through a non-corrosive valve. Media that tends to reach high temperature or pressure should pass into a strong alloy with internal coating. Actuation also plays a big role in choosing the right throttling valve.

In pipeline applications, there are instances that strong pressure is present. A manual actuator may not be efficient in opening or closing the valve because of that. How the valve is connected to the pipes is also worth considering. It is important to adapt to the existing pipe connections rather than the pipes adapting to the valve. It is more cost effective to suit the valve to the existing pipe requirements.

For instance, when the pipe ends have flanges, the valve should also have flanged end connections. Industry standards are just as important. There are standards for the type of material to use for a particular media. There are also standards on end connections or the thickness of the metal to use for the valve. Such standards bring safety to applications.

There is often an increase in temperature and pressure when using throttling valves. By that, it is vital to understand such standards for the safety of everyone. The control of flow is difficult because of the valve's design, and the flow of fluid slapping against a partially open gate can cause extensive damage to the valve. In this valve, the stem rises out of the valve when the valve is opened.

How do you choose a valve type? Valve type selection should take account of : Required function. Service conditions. Fluid type and condition. Fluid characteristics. Frequency of operation. Isolation requirements. Maintenance requirements. Environmental considerations. When would you use a gate valve?

Gate valves are often used when minimum pressure loss and a free bore is needed. When fully open, a typical gate valve has no obstruction in the flow path resulting in a very low pressure loss, and this design makes it possible to use a pipe-cleaning pig. What type of valve is a control valve? Control Valves? A Control Valve is a power-operated device used to modify the fluid flow rate in a process system. There are two basic types of control valves Control Valve a Rotary motion valves having ball, butterfly or plug type closures.

Can globe valve be used for throttling? Globe valves. Conventional Globe valves may be used for isolation and throttling services. What is the difference between a ball valve and a butterfly valve? Generally speaking, a ball valve is a ball with a hole through it.

A butterfly valve generally consists of a disk mounted on a rotating shaft. The top of the stem just below the handle is threaded and the stem drops further down into the flow path a small amount each time the handle is turned. This allows you to control the amount the valve is closed and the amount of flow thru the valve. Needle valves are generally a smaller valve and most are able to be throttled down to just drops per minute.

They work similar to the globe valves with fine pitch thread for precision adjustment and are ideal for metering flow. Butterfly valves are sometimes used for throttling applications often where a larger size valve is required, but they are somewhat limited in what they can do and how well they work for throttling. Search More Articles.