Science and technology have evolved significantly over the years, making our lives relatively easier. Among these technologies are mechanical devices that protect the building structures for occupants and allow them to operate properly, while also ensuring environmental safety. Valves are one of those crucial elements used in various mechanical systems to control the movement of liquids, powders, gasses, etc.
Pumps and piping systems require more attention when it comes to the design and management of fluid transportation. The type of pump and piping signifies the pressure of fluid passage through the system.
Importance Of Valves In The Mechanical System
Before getting into the types of valves, let’s try to understand their importance. Valves are electro-mechanical or mechanical devices used to control the movement of fluids through tubes or pipes from tanks or huge containers.
Valves help in securing safety in process plants by controlling and regulating flows. Process plants are industries that process bulk resources into finished products. These industries have factories or plants with many pipes and tubes that control the flow of various materials such as water, oil, pulp, or gas. This explains why valves play a key role in all industries.
Sometimes the materials that flow can be quite hazardous and erosive. In such cases, the valves can prevent accidents, thanks to their durability and reliability, even during demanding conditions. However, they need to function efficiently and steadily, irrespective of material passing through them.
Types Of Valves
Material selection plays a major role in specifying valves to ensure the compatibility of certain parts of the valve with the fluid passing through it. Sizing can be easily determined by the tubing or pipe diameter, flow rate, and width between flanges for pipe valves that will be installed. However, it is also important to determine what will be running through the pipes and valves to make the material selection easy. The different types of valves and their respective uses are as follows:
- Aerosol Valves: These are used for dispensing the contents of aerosol cans. Aerosol valves contain two primary components, the stem, and the housing. The specifications include actuator type, intended application, valve size, output type, and construction materials. Media dispensed can also be considered. It releases creams, liquids, ointment gasses, cleaning agents, and other products packed in an aerosol can.
- Check Valves: Pneumatic check valves allow fluids to flow through them in one direction. Lift-type valves are constructed as globe valves and often use a ball or piston backed by a spring that opens under a particular kind of pressure but closes when the pressure minimizes, preventing backflow. They are used on gas lines and for air services and can be manufactured in plastic.
- Diaphragm Valves: These are equipped with flexible membranes which close off flow in pipes. The diaphragm valve completely shuts or seals off the actuating means from the process fluid, which is an advantage in sanitary services. Its specifications include port, connections, port configuration, media, valve size, and seal material. Diaphragm valves are mostly used in cosmetics, pharmaceuticals, food, and semiconductor factories.
- Blowdown Valve: Blowdown takes place after water removal from the boiler while it is still operating. The suspended particles are then removed from the fluid by blowing down the boiler. A blowdown valve’s main function is to control an intermittent or continuous flow of steam or fluid under high pressure. When installed in the piping and tubing system, they drain the solid contaminants from the fluid.
- Double Block and Bleed Valves: They can be mechanical and even electro-mechanical devices consisting of dual inline single bleeder valves and double blocker valves in common bodies. They are used for separating fluid lines from upstream pressure. Key specifications of the bleeder and double block valves are the port connection type, actuator type, intended application, flow coefficient, pressure rating, media, etc.
- Blowoff Valve: Also known as a compressor bypass valve or dump valve, a blowoff valve is a pressure release system present in petrol turbocharged engines. It helps create a seal between the combustion chambers and the intake or exhaust system. Its key specifications are head and stem diameter, intended application, and the material. The closing and opening of engine valves are controlled by a series of springs and cams.
- Unloader Valve: Air compressor unloader valve is a small part, measuring approximately 4-5 inches in length and width. Its chief function is releasing trapped air that is present inside the tank or container, enabling the motor to start. Commonly used in hi-lo pump circuits, they are also used to dump leftover fluid into the tank at very little or no pressure.
Application Of Valves
With few exceptions (aircraft fuel valves or refrigerator valves), valves are not factory-specific and can be used across industries. Some of them are dedicated to aerosol valves and check valves, while others are for general pipelines such as diaphragm valves. Then there are valves like unloader valves that activate automatically under specific circumstances, such as fluctuating pressure. Some valves are commonly used, grouped by functions such as boiler and blowdown valves and unloader valve air compressors.
Any valve with automatic actuators are ideal for functioning as control valves since they are mostly tied with controllers of the remote process. Many controlling valves have some form of manual control by which valves can be closed and opened. As for pipeline valves, many can be suited to either throttling or to blocking.
| Types Of Valves | Their Application |
| Aerosol Valves | Deodorants, perfumes and hairsprays |
| Check Valves | Feed water control system, miscellaneous systems, etc. |
| Diaphragm Valves | Pulp, water, chemical, pharmaceutical and bioprocessing |
| Blowdown Valves | Controls intermittent flow of fluid or steam |
| Double Block and Bleed Valve | Prevents product contamination, piping isolation for maintenance |
| Blowoff Valve | Prevents compressor surge, reduces system pressure |
| Unloader Valve | Dumps excess fluid at little pressure |
Wrapping Up
Valves are necessary for mechanical systems to keep accidents or hazards at bay. But before you select valves for your process plants, it is advisable to consider a few things. We highly recommend identifying whether it will be used for throttling or for start-stop operations, the nature of the fluid that will flow through the valve, etc.
