Valves serve a variety of purposes in the industrial, engineering, manufacturing and scientific communities. Selecting the right valve can determine the success or failure of the system or process.
The main purpose of a valve is to control media flow through a system. The valve may be used to start, stop, or throttle the flow to ensure safe and efficient operation of the process. To learn more about the mechanisms that valves use to control flow, please read Valve Types.
Valves play a large role in most industries. They are used in many parts of daily mechanical devices, including in HVAC and water systems in an office and the gasoline mechanism for an automobile. Below are a few examples of the many industries in which valves play a major role in proper operation.
This use is an essential aspect of many industries, but there are hundreds of thousands of miles of crucial pipelines that transport media from its source to the place where it will be transformed into its final product. This media could include piping for crude oil and gas, both onshore and offshore. Valves are used to optimize the pipeline operating conditions, and can be found in the upstream, midstream and downstream section of the piping. Upstream starts at the bottom of the hole in the ground and covers everything on the wellhead up to the choke. In this case, the choke is a specialized globe valve that is mounted on the wellhead to regulate the output of the well. Midstream starts at the output of the choke and ends at the fence of the final destination (usually a refinery). Downstream is everything inside the area of the destination. The most important factor to consider when selecting a valve for a pipeline application is whether the valve is piggable – that is, the inside is designed to be cleaned or inspected.
Image Credit: W.L. Sunshine
Oil and Gas
The oil and gas industry is a subset of the pipelines category. Due to the high demand for oil and gas, deeper wells, longer pipelines, and lower production costs have become necessary. Along with the need for an inexpensive valve, the device must also be tougher, last longer, and perform better to meet the demands of the industry. Valve service environments and operating conditions are often extreme with high temperatures (greater than 1,500°F) and high pressure (greater than 25,000 psig) or cryogenic and very low pressure applications. Another feature important to valves used in the oil and gas industry is the capacity for remote control.
Image Credit: Univalve
Food and Beverage
The food and beverage industry is a large and growing industry with an increasing need for parts and products that keep plants running smoothly .The industry’s many challenges, including safety concerns, have prompted strict material requirements for the valves used in these plants. There are two classifications for valves in the food and beverage industry: those in direct contact with food materials and those handling utility services (i.e. steam, water). For valves which come into direct contact with food, there are regulations in place (issued by such organizations as the FDA) which require that the inside of the valve be smooth enough to avoid trapping particles or bacterial accumulation. Valves made of a soft material must not absorb or hold any product going through the valve. These standards also specify that there should not be dead volume in the valve or crevices where material can be trapped to avoid decay or stagnate. Valves in the food and beverage industry do not face the high pressures or highly corrosive materials that are present in other industries.
Image Credit: Nordson
The biopharm industry is part of the larger chemical processing industry. The most important feature of valves used in this industry is their ability to be cleaned and sterilized. The chemical processing industry is responsible for processing raw materials into products. Since chemical processing often involves reactions using pressure and/or heat, and could cause toxic by-products, the media in this industry tends to be highly corrosive and abrasive. The valves need to be able to tolerate the nature of the media, as well as offer precise flow control and high leakage protection to protect against spills and cross-contamination.
Image Credit: RS Engineering Works
Valves play a critical role in the marine industry. As ships become larger and are used more frequently, they require the ability to generate power, treat and manage wastewater and control HVAC, as well as perform their required tasks. The size and application of the ship will determine the different types and number of valves on board. Valves are used to regulate the loading and storage of a ship’s power supply, provide water for fire-fighting capabilities, handle and processes wastewater and store any liquid cargo, among many other applications. Any valve that processes sea water must be durable, and all marine valves must be reliable due to lack of resources once out at sea.
Firefighting system on a ship. Image Credit: Fire Fight Systems
These are just a few examples of the many industries and applications of valves.
The system media is a critical consideration when selecting a valve. Media is a term used to describe the material that will be passing through the system. Media plays an important role when selecting the valve body and disc composition as well as the type and speed of the actuator. There is a wide variety of materials that could be used in the valve system; these include:
- Gas: Valves for gas systems seal tightly up to a minimum specified leakage rate at rated operating temperatures and pressures.
- Air: used to describe all non-pressurized air.
- Compressed air: used to describe pressurized and potentially explosive air.
- High purity, natural gas, sour, specialty or corrosive
- Liquefied petroleum
- Liquid: Valves for liquid systems require tight seals to prevent leakage.
- Water (hot or cold, clean or dirty, fresh or salt)
- Gasoline (diesel fuel)
- Hydraulic fluid
- Highly viscous or gummy fluids
- Solid: Valves for solid materials must be durable and have few parts to prevent clogging.
- Slurry: A slurry is a solution with suspended particles. For this media type, the valve must be able to operate effectively in aggressive conditions.
Powder: The chart below describes several common media as well as the appropriate valve to use for the application.
Valves can be found in non-industrial applications. These may include valves used for residential applications such as a faucet or outdoor hose, or in medicine such as a heart valve.
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