Valves and Taps Overview

What Are Valves?

Valves provide a means to control the flow of liquids and gasses. They utilize various means of obstructing a pipe to provide flow blockage. Each design has its own advantages and disadvantages and its specific applications.

Valves can be remarkably simple, such as check valve, which restricts fluids and gasses to flowing in one direction only. They can also be complex. Some valves, for instance, use solenoids to control their open and closed states and are completely automatic in their functions. They can also use many different means of obstructing flow.

A globe valve, for example, is provided with a chamber—spherical in shape, hence the name—that has a baffle in it. A disk is plunged into the opening in the baffle to obstruct water or other fluid flow, providing a tight seal and allowing for reliable control. A gate valve uses a simpler mechanism, obstructing flow with a simple metal piece that completely shuts off a pipe. Some valve mechanisms are chosen because of their capabilities to allow unobstructed flow, such as in the case of the aforementioned gate valve, which can be withdrawn from a pipe completely, allowing fluids and gasses to flow without any hindrance.

Valves will have a manual or automatic actuator. Manual actuators are commonly hand wheels or lever types. Some are characteristic of particular types of valves. Ball valves, for instance, which are often employed as relief devices, are frequently provided with a simple lever that allows them to be opened very quickly.

Valves are also used to isolate particular equipment. A pressure gauge, for instance, can usually be isolated from a line by closing off a valve. This allows the gauge to be removed or serviced without eliminating the pressure in the line, allowing processes to continue while the work is being done on the gauge.

Some valves are employed to vent unwanted gasses or fluids from lines automatically. These are very common on steam systems, where incondensable gasses and liquids may need to be vented off to ensure that the system performs and intended.

Some industries tend to use specific types of valves. Refineries, for instance, tend to have many gate valves in their facilities, as they make it easy to open and close lines completely, providing precise control over the flow of liquids through the piping systems.


What Are Taps?

Taps are also known as faucets and sometimes spigots. The main function of these devices is to allow liquid or gasses to be released from a line. This may be done for practical purposes—hooking up a hose to a water line, for instance—or for safety purposes.

Taps are sometimes very simple devices, allowing the user to get flow from a line. In other cases, however, they’re provided with the ability to mix fluids. One of the most common examples of this are the valves used in showers, which mix hot and cold water so that the user can be comfortable.

Taps are usually fitted with a threaded portion that allows for the attachment of a showerhead or another means of controlling and directing flow. The showerhead or other device may contribute to controlling the pressure coming out of the tap. A low-flow showerhead, for instance, can ensure that the rate of flow out of a showerhead doesn’t surpass a given rate, allowing the user to save water by not allowing water to flow freely out of the line.


What Are Valves and Taps Used For?

Valves and taps both provide a means of controlling and directing the flow of liquids and gasses. Valves allow a section of line to be opened up or closed off to the flow of either. Taps allow a user to release liquid or gasses from a line.

Both of these devices are used in safety applications for systems. Automated systems allow valves to be opened and closed via electrical controls, based on pressure and in other ways that provide regulation of a line.


What Are the Various Types of Valves and Taps? How Does Each Type Work? How Does It Look Like? What Is It Used For?


Air Vents

These are used to automatically remove incondensable gasses and air from steam lines. They are energy saving devices and can help to maintain needed temperatures for processes. They are simple looking devices with a hole for venting air.


Butterfly Valves

Buttery fly valves are commonly seen in automotive applications. They have a disc, suspended in the middle of the pipe. A rotating axis provides a way to obstruct or open up the pipes by changing the orientation of the “wings” on the device.


Check Valves

The “check” in check valve refers to the fact that it checks fluids from flowing backward in a pipe. They are integral to backflow prevention. They are among the simplest types of valves.


Chemical Tanks

These are sophisticated devices, sometimes designed with LED readouts and solenoid-controlled drive mechanisms. They are usually translucent or clear.


Diaphragm Valves

These are very versatile valves that consist of a diaphragm of a flexible material and a means of extending it to the bottom of the pipe, preventing fluids from flowing. On the outside, they are commonly opened with hand wheels. They can be mounted in any position on a pipe.


Drain Cocks

Drain cocks are usually situated at the lowest point of a tank. They’re used to vent off liquids from the tank. They appear very similar to a bolt.


Electronic Flush and Flow Controllers

These devices provide an automated way to control the open or closed state of a valve. They are used to flush systems out and, when a cycle is completed, they can automatically close, preventing further flow.


Gate Valves

These valves are used heavily in the petroleum industry. In the valve, a metal wedge is screwed down into place by the operator. They can be completely opened, making them useful when a pipe has to have a completely unobstructed flow at times. They are usually operated with hand wheels or automatically.


Globe Valves

Globe valves have a disc that descends to block a flow path that’s partially obstructed by a baffle. They are excellent valves for systems that need to be opened and closed frequently. They are usually operated by a screw and can be automated. Their name comes from their spherical outer shape.


Manual Ball Valves

These are commonly used in shutoff valves and are often operated with a lever. inside the valve is a ball with a hole through it. When the valve is open, the hold is aligned with the pipes and permits flow. When it is closed, the hole is rotated perpendicular to the flow, shutting it off completely.


Motorized and Actuated Valves

Motorized and actuated valves can be operated by machines, providing a valuable role in automated processes.


Needle Valves

The needle in these valves is the plunger, which has a tapering shape like a needle. These are usually small valves, more useful in precise, small applications than in controlling the flow of large amounts of liquid.


Pneumatic Operated Process Valves

These are operated by air pressure and come in many different types, from globe to ball to cylinder types and more. Maximum working pressures are important considerations when choosing these types of valves. They function to control the flow of fluid and to direct the flow of fluid. They can be partially or fully opened or closed.


Pressure Gauge Cocks

These can shut off a pressure gauge from the rest of the line, allowing it to be removed or replaced. They come in many different sizes and are used in applications where the pressure in a line has to be maintained but where isolation of gauges is sometimes necessary.


Pressure Reducing Valves

These are used to bring pressures down to safe levels. They usually cut off the flow of a liquid’s flow when it exceeds a given pressure, saving a line from damage.


Pressure Relief Valves

These are used to release excess gas or liquid in a line that contributes to greater pressure. They are safety devices that prevent physical harm to workers and damage to equipment.


Process Ball Valves

These are commonly used for isolating fluids in applications involving instrumentation and processes. They come in a range of attachment types and pressure ratings.


Process Check Valves

Used in instrumentation applications, these valves can check the flow of gasses or fluids.


Process Needle Valves

Process needle valves are used in power and instrumentation applications. They provide very effective shut-off and regulation capabilities.


Process Valve Bases

These come in different sizes and designs, with bodies made of durable materials such as anodized aluminum. Some come supplied with fixing screws and other hardware.


Shower Controls

These devices include mixers and sometimes other hardware, such as hand spray attachments. They provide a safe way to control the temperature of water in showers. They sometimes have one control and sometimes have two separate controls for the hot and cold lines.



Showerheads can be used to adjust the pattern and pressure of flow, or to reduce flow for certain applications. Their designs vary widely.


Solenoid Valves

These powered valves are available in designs that are suitable for use with fluids and gasses. They also come in various pressure ranges and with different types of electrical connections.


Solenoid Coils for Process Valves

These devices are matched to specific types of solenoid valves and provide the capability of handling fluids and gasses. The coil switches positions when it is energized or de-energized.


Solenoid Controllers for Process Valves

Solenoid controllers are commonly used to open and close valves automatically and are used in a variety of different applications.


Solenoid Valve Adapters & Mounts

These are programmable devices that sometimes contain enhancements like LED indicators and other features. Advanced designs allow them to be adjusted without removing the unit from the line.


Spray Guns

These come in gravity fed designs and other options. They are differentiated by the pressure required to operate them, the size of the inlets and the transfer efficiency. Material output is another important consideration with spray guns. Some spray guns are fitted with tanks and others are not. They are usually triggered by a simple lever.


Steam Traps

These devices can automatically discharge unwanted gasses and prevent issues that arise from back pressure and other hazards.


Stop Cocks

Stop cocks can shut down the flow of liquids and gasses. They come in a variety of different options, including different heads, threading and pressure ratings.


Tank and Cistern Float Valves

These are differentiated by pressure, the size of the tank that they’re suited to work in and the point of entry into the device. They are commonly seen in any applications where the water level in a tank or cistern needs to trigger a valve.


Tank and Cistern Floats

The actual floating component of a float valve, these are buoyant devices designed to rest atop a fluid. They come in a variety of sizes and are usually colored balls that float on top of the fluid. They are commonly seen in the tanks of toilets, where the control the water flow into the tank based on the water level.


Taps with Hose Unions

These provide a means to tap into a line and are supplied with an attachment for a hose. They have varying valve designs, making them suitable for a variety of different applications.


Thermostatic Washroom Valves

These mixing valves come in different fittings and body styles. They can operate without any electricity or pneumatic pressure, allowing the flow of water to be controlled automatically.


Valve Actuators

These devices can open or close valves. They are electorally powered and many contain more than one power head. They usually appear as plan, square devices mounted to a valve control.


Water Taps

These devices come in a huge range of designs and provide the main means by which a line is tapped into. They can have one or two controls for controlling the temperature and flow of water.