The different types of flow valves used in the oil industry include globe, API and ASME gate, butterfly, check, and ball designs, all used in different applications. To understand more about how a flow controller works, we need to define it first.
What is a Flow Valve?
A flow control valve is a mechanical device used in the liquid flow industry for regulation, controlling, and closing & opening flow pressure in fluids. In high-pressure or small-bore applications, ideal flow valves are forged valves. For pipes that are above 2 inches, cast valves will work out well. In this article, we will focus on valve types used in the oil and gas industry. Since there are many types of automatic valves used in the gas and oil industry, they are grouped into different categories:
Disc Type Valves
- Linear Motion – Some of the valves that belong to this category include globe, gate, pinch, diaphragm, and check valves.
- Rotary Motion – Valves in this category include plug, ball, swing check valves butterfly, plug, and eccentric valves.
- Quarter Turn – These types of flow valves move from fully close to a fully open position or vise versa and require approximately a quarter turn motion, from 0 to 90° of the stem.
Material-Based Valve Types
- Cast – These types of flow valves are made by casting steel.
- Forged – These types of flow valves are made from forging steel.
The flow rate of gas and oil is regulated using control valves. This is done either in the process or while passing through the pipeline. They follow set parameters of pressure, level, and temperature, based on the controller-managed signals. Control valves are vital devices in the petrochemical industry that uses complex processes. Control valves are there to ensure processes are carried out as intended since multiple loops are involved and should be kept under strict control. This helps to provide the desired results in quality, quantity, and time.
The growing demand for automated processes in many industries has led to increased flow control valves in the last few years. Some of the sectors that use automated valves include power generation, water treatment plants, fire prevention systems, gas & oil, and food processing industries. They help to provide greater safety for both equipment and personnel, streamlined and quicker responses in production.
The type of control valves used have either globe, butterfly, or ball shape in the oil and gas industries. They also come in different sizes and material grades. An air-operated actuator is often used in these types of control valves. This is because they use switchgear and cabling, which are less ancillary equipment. The regulation of the opening and closing of the valve is made with the actuator, electronic controller, and positioner’s combined effort. The actuator can either be pneumatic, hydraulic, or electric.
The changes in key process parameters in the control valve trigger the opening and closing of the actuator. These include temperature, level, pressure, and flow changes. These actions are used to maintain the parameters, and this is done according to the target range. This ensures that the entire process works as intended. It also ensures that the end products are of the desired quality and quantity.
Components Found in a Control Valve
A flow control valve is made up of several components, including:
The Valve Body – The body of the valve contains the modulating element and is where it operates.
The Positioner – This is the element in the valve used to control the degree to which the valve opens. It is mounted on the body of the valve.
The Actuator – This component in a control valve is used to move the modulating element. The element can either be the stem (globe valves), the disc (butterfly), or the ball (ball valves).
Flow Controller Actuators
When selecting an actuator, it must be done based on the needed rod thrust and valve movement. Determining if the diaphragm or the piston actuator is the right type is paramount. This is because they are used to move and position the flow control element as the primary energy source within the valve’s body. Actuators are available in many types. They include electric, pneumatic, electro-hydraulic, hydraulic, and manual actuator types. The most commonly used actuators in throttling applications are pneumatic types.
Based on the automatic control valve standards used in the past, there are three types: piston, rotary vane, and spring-and-diaphragm. Piston and spring-and-diaphragm pneumatic actuators can be adapted to be used in either sliding-stem or rotary valves. Rotary vane actuators can only be used with rotary valves.
The oil and gas industry requires the highest accuracy and safety levels because most of them are quite flammable and hazardous. That is why they require flow control valves that work according to the parameters and priorities set in the industry. These products are also expensive, therefore using an appropriate automatic flow controller helps to prevent wastages.
MD: Are you looking for an automatic flow controller to use in your application? Read on to find out more about flow valves that can be used in the oil industry.