Views: 68 Author: Site Editor Publish Time: 2022-12-19 Origin: Site
The chemical industry is one of the most critical industries in the world. It produces many products, including pharmaceuticals, cosmetics, food and drink, and cleaning products.
One of the most critical aspects of the chemical industry is the use of valves. Valves control the flow of liquids and gasses in various settings and come in a wide range of different types. In this blog post, we will explore the different types of valves used in the chemical industry and how they are used to control the flow of chemicals.
What Is Chemical Valves?
A chemical valve controls the flow of chemicals and other fluids. Chemical valves are used in various industries, including oil and gas, petrochemical, pharmaceutical, and food and beverage. Chemical valves come in different materials, including metal, plastic, and composite. Petrochem valves are also available in various sizes, from small valves for home use to large valves for industrial applications.
How Do Petrochemical Valves Work?
Petrochemical valves are designed to open and close to changes in pressure, temperature, or fluid level. The most common type of petrochemical valve is the ball valve, which uses a ball-shaped plug to control the flow of liquids and gasses.
Ball valves are often used in applications where a high degree of accuracy is required, such as in natural gas pipelines. They are also used in applications where a quick shut-off is needed, such as oil refineries.
Other petrochemical valves include check valves, which allow fluids to flow in one direction only; gate valves, which control the flow of liquids by opening and closing a gate; and globe valves, which regulate the flow of fluids by opening and closing a globe.
1. Globe valve:
Globe valve: It operates by reciprocating action of disc or plug. The disc or plug moves to or away from the seat thereby stopping the fluid flow or allowing the fluid to flow. The disc or plug seats over the valve seat. The valve seat can be removable. Pressure drop in the Globe valve is high.
The valve can be manually operated or power actuated or automatic actuated. Globe valves are available from 12 mm to 300 mm size and their temperature and pressure limits are 550 C and 150 kg/cm2 respectively. Material of construction for globe valve is carbon steel, stainless steel, ductile iron, brass, and other corrosion resistant alloys.
2. Gate valve:
Gate valve: Gate valve functions by the reciprocating action of disc in its body. It can have a single disc or double disc. It is used for shut off operation. In double disc valve shut off is good.
Gate valve can have rising or non-rising stem. Gate valves are available in various sizes ranging from 12 mm to 300 mm and even more. Gate valve is light in weight, economic and offers low pressure drop. Conduit type gate valve is common in chemical process industries because it gives accurate flow control. Gate valve can be used upto 20 kg/cm2 and upto 675°C. Material of construction for gate valve is cast iron, carbon steel, stainless steel, ductile iron, bronze, nickel alloys etc. Rotating disc type gate valve with quick action lever actuator.
3. Ball valve:
Ball valve: Ball valve has a spherical plug. The spherical plug is a controlling element. They are widely used in chemical process industries. It is used where throttling and shut off combination is required. It offers good flow characteristics. Ball valve consists of a two way globe and the ball rotates between resilient seats. It is compact and requires low maintenance and no lubrication. It is available in venture pattern, reduced and full port patterns. By giving a quarter turn to the ball, the valve can be closed or opened. The valve does not give good throttling. It can be available in size from 6mm to as large as 900mm. It can be used for pressures upto 500 kg/cm and temperature upto 300°C.
Full port ball valve is shown below.
4. Butterfly valve:
Butterfly valve: In Butterfly valve the controlling element is a disc called as blade, vane or flapper, which rotates in horizontal or vertical direction and allows the fluid to flow. Butterfly valve is suitable for throttling or on-off operation at low pressure drop.
It is economic, easy to install and does not allow the solids to build up. Butterfly valve can be either screw type or of wafer type. Its operation can be manual, power, or automatic Water type butterfly valve is shown. Butterfly value can be used for vacuum operations or pressures upto 80 kg/cm2. It is available in size ranging from 50mm to as large as 900 mm. The blade or flapper of a Butterfly valve can be made from rubber, neoprene, chloro sulphonated polyethylene etc.
5. Diaphragm valve:
Diaphragm valve: Main parts of a diaphragm valve are, body, bonnet and a flexible diaphragm. Diaphragm is lifted