Are you trying to figure out what control valve sizing you need? It may seem like it’s easy to figure out just by looking at the pipes, but it takes more than that.

Control valves come in different styles and sizes based on several factors. You need to consider the flow characteristics, noise, actuator sizing, and more. As much as possible, it’s also best to avoid getting the wrong size if you don’t want to cause damage.

So, how do you figure out what control valve size you need? Here’s a guide on what you need to know.

Cavitation

Cavitation is when a liquid’s static pressure reduces beyond its vapor pressure, causing high noise and vibration. This can result in damage to the valve’s internal parts and downstream pipes.

With the right control valve size, you can prevent sudden pressure drops with the liquid. And so, preventing cavitation from damaging the valve and pipes.

Noise

When cavitation exists, it leads to high noise levels in the valve. It also causes a vibration that damages the rest of the equipment.

The bigger the valve and pipe size, the more likely the noise will pass the standard levels in steam and gas services. It applies even when the pressure drops are mild.

So, when it comes to oil and gas, it’s necessary to factor in noise levels when evaluating a control valve size chart.

Choked Flow

Other impacts of cavitation include choking. Basically, when the downstream pressure drops beyond the point of flashing, it results in choked flow. Experts suggest knowing the level of cavitation when choked flow may occur to prevent it from getting there.

Flow Characteristics

The flow characteristics of the control valve refers to the relationship between the valve output and flow. Once it starts operating, the inherent flow characteristic changes.

This means other factors, including pressure drops and valve location, can affect the flow characteristic. It helps to get an analysis of these when sizing a control valve for better accuracy.

Actuator Sizing

Figuring out the actuator sizing is a lot more straightforward than choosing the right control valve size for it. You will have to consider the opening angle and pressure drop at that angle of the valve’s torque.

Many recommend getting a computerized analysis when you need to consider actuator sizing when choosing valve sizes.

Valve Style

There are many types of valve styles available, each with a different purpose. Some of these have more resistance, range, availability, and price ranges.

A popular choice is a globe valve, offering the widest range of options given the mentioned considerations. But these are usually on the pricey side.

There are also segment ball valves. These have better rangeability and flow capacity than globe valves, and are relatively cheaper. The downside is their limitation when it comes to other extreme factors.

If you’re interested in other types of valve styles, you can check for valve wireless sensors linked here.

Consider These Factors When Choosing a Control Valve Sizing

There are many factors to consider when looking for the right control valve sizing, especially if you want to prevent damage to your equipment. Due to the complexity, remember to contact professionals for assistance whenever necessary.

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