Types of Water Valves
Posted by Russ Bailey on Sep 3rd 2024
Hey there, fellow valve enthusiasts! We all know that valves play a crucial role in regulating the flow of liquids and gasses in a broad range of applications, from automotive to manufacturing, mining to oil and gas. Something you might not know, is that valves are critical in getting water flowing out of your tap. If you'd like to know all about the types of valves used in the water industry, ValveMan is here to help!
Water valves are essential components the water sector. These valves form part of water and wastewater treatment plants, bulk water supply, reticulation, commercial and residential plumbing systems. They regulate, direct, or control the flow of water to ensure efficient operation and safety. Various types of water valves are available, each designed for specific applications. Understanding their differences can help you choose the right valve for your needs. In this blog, we’ll explore different types of water valves, detail their functions, advantages, and where they are typically used.
Whether you’re upgrading a domestic hot water plumbing system, or replacing an old gate valve on a water main, knowing about water valves will help you get the job done quickly and effectively.
Shutoff Valves
Let's begin by looking at the most common valves used in water systems: ball valves, gates valves and butterfly valves. These are all isolation or shut-off valve types, used to stop, start and direct the flow of water into different areas within water treatment, distribution and plumbing systems.
Ball Valve
Ball valves, known for durability and excellent shutoff capabilities, are pivotal components in both large and small scale water distribution systems. These valves use a rotating ball element with a hole through its center to regulate flow. The hole aligns with the flow when open, and remains perpendicular to the flow path when closed. Ball valves are favored for applications that require a reliable seal and easy operation, even after periods of disuse.
Ball valves come in various designs, including trunnion, floating ball, full, reduced or multi-port, single or split body configurations. There are also many material options available for valve body, stem, ball and seat; including brass, stainless steel, and PVC; catering to different pressure and temperature conditions. These valves are readily available with quarter-turn levers or actuators. Ball valves are easy to operate, repair and maintain, making them a popular choice for managing water flow in homes and industries.
Ball Valve [ Image Link]
Gate Valve
Gate valves operate by raising or lowering a gate inside a valve body. The water path clears as the gate lifts, and is obstructed as the gate lowers. Gate valves are often used where operation is infrequent, such as in underground pipelines or washout stations. Note that gate valves are not suitable for throttling flow, as partial openings can cause excessive velocity and vibrations leading to valve damage.
Gate valves are available in various configurations, including parallel and wedge gate type, rising and non-rising spindle, metal and resilient seated. Material options including stainless steel, cast steel, bronze and ductile iron. Materials are often selected based on the service fluid, pressure and temperature considerations. Gate valves commonly found in water applications include resilient seal gate valves, which employ rubber encapsulated gates or seats and metal seated wedge gate valves. Knife gate valves are commonly found in wastewater treatment applications. Gate valves are commonly supplied with handwheels, gearbox drives and actuators.
Gate Valve [ Image Link]
Butterfly Valve
Butterfly valves, recognizable by their short pattern and disc-shaped closing mechanism, pivot in the center of the valve to control water flow. This design allows for quick operation and minimal disruption to the flow of water, making them an excellent choice for systems that require regular fluid control. The compact and lightweight nature of butterfly valves makes them advantageous for installations with limited space.
Butterfly valve configurations include double and triple eccentric designs, soft and metal seats, wafer, lugged and flanged connections. Butterfly valves may be quarter-turn, lever operated, or supplied with a gearbox and handwheel or actuator. Available in materials such as cast iron, cast steel or stainless steel, butterfly valves can be used in a variety of settings, from bulk water systems to water treatment plants. Avoid butterfly valves in waste water applications, as stringy and fibrous material may get stuck on the valve disc. Note that the preferred disc orientation is dependent on where the valve is installed.
Butterfly Valve [ Image Link]
Specialty Water Valves
Specialty water valve types include valves used for operation, control and safety purposes. Examples of these valves include check valves, air valves, globe valves, diaphragm valves, pressure reducing valves and pressure relief valves. Let's look at these valves in more detail.
Check Valve
Check valves, also known as non-return valves, reflux valves and one-way valves, are specialized devices that allow water to flow in one direction only. These valves are critical in systems where backflow can cause operational and safety issues, or damage to equipment. Check valves are found in domestic water applications, water and waste water treatment operations, and pumping systems.
Check valves contain a closure element which operates automatically, closing once the flow of water stops or begins reversing. Many check valve designs are available. Common types of check valves found in water applications include ball type, lift type, spring type, piston type, single and multi-door swing type, nozzle or 'silent' type. Check valve selection is primarily dependent on the velocity of the water, operating pressure of the system and valve cracking pressure requirements. Other considerations include valve size, water quality and the potential for water hammer and surge scenarios.
Check valves are available in a variety of materials, with common options being brass, bronze, cast iron, cast steel and stainless steel. Small bore check valves are typically threaded or compression type connections. Larger check valves are flanged, with numerous form factors such as wafer, lugged, short or long patterns available.
Check Valve [ Image Link]
Air Valve
Air valves play an integral role in the operation of water piping systems, particularly bulk water pipelines. These valves allow for air removal during pipeline filling, and air admission during pipeline draining or scouring. They also eliminate entrained air during normal pipeline operation. This prevents the formation of air pockets and air locks in a pipeline, and improves efficiency by ensuring that slugs of air are not transported along the pipeline. Air valves also prevent vacuum conditions from developing in a pipeline, averting potential pipeline collapse.
Air valves are usually installed at high points along a pipeline, where air naturally collects, or at other critical points in a pipe system. They are also installed on pump discharge lines, and at siphons. Air valves are automatic, functioning without the need for intervention unless maintenance is required, which involves simple cleaning or replacement of parts. Essential for stable and efficient operation, the placement and performance of air valves directly influence the operational dynamics and safety of water transportation systems.
Different air valves models are available, to cater for a variety of applications. These range from single acting air vent valves, to triple acting air valves with air release, vacuum break and anti-shock functionality. A number of air valve designs are found in water applications. These include ball floats, cone floats, and poppet designs. Metallic valves manufactured from stainless steel, cast steel and iron are commonly installed on bulk water pipelines, while plastic valves are widely used in agricultural and irrigation applications.
Air Valve [ Image Link]
Control Valves for Water
Control valves play a crucial role in bulk water distribution, water reticulation systems, and plumbing. These valves may be used to limit or maintain water pressure in a network, or regulate water flow. Control valves are also used to manage water levels in reservoirs, towers and tanks. Let's look at control valve types commonly used in water applications.
Globe Valve
Globe valves are used to control the flow of water by raising or lowering a disc (also referred to as a plug) located within a valve body. This mechanism allows for precise flow regulation, making globe valves ideal for flow control and throttling applications. The disc moves perpendicular to the flow, allowing the valve to move across a range from closed, to a percentage open, to fully open.
Globe valves are used in situations where flow needs to be adjusted frequently. The range of flow control required, pressure drop across the valve, and duty cycles must be considered in the design of the valve, to prevent early failure and to assure exceptional service.
Globe valves are available in a variety of configurations, including tee pattern, angle pattern and wye pattern. Smaller valves are usually supplied with threaded or socket weld ends, while larger valves are typically flanged. Common materials used in globe valves include cast steel, stainless steel and cast iron. Valves subjected to high-differential pressure-throttling service require specially designed valve trim.
In water applications, globe valves are commonly found at pump discharges, in water distribution networks and at reservoir or tank inlets. Globe valves are durable and reliable, ensuring efficient operation and flow control over a long period.
Globe Valve [ Image Link]
Pressure Reducing Valve
Pressure reducing valves are used to limit the pressure in bulk water systems and water distribution networks. Also known as PRV's, these valves play a crucial role in ensuring that water pressure in a system remains within an acceptable range. Pressure reducing valves protect pipes and other in-line equipment from excessive pressure. Pressure reducing valves help regulate the pressure entering a house or building from a municipal supply or pumping scheme. This valve reduces the incoming pressure to a safer, more manageable level, which prolongs the life of the plumbing system by reducing stress on pipes and fixtures. Additionally, it can help lower water consumption, providing a more eco-friendly and cost-effective solution to managing water supply. Pressure reducing valves are found in residential, commercial and industrial water applications.
There are many types of pressure reducing valves available. Common valves employed in water service include self-acting hydraulic actuated pressure reducing valves, spring activated valves, and solenoid actuated valves. The valves are commonly angle or wye pattern globe valves, with hydraulic pilot fittings or spring attachments incorporated for pressure reduction.
Performance Control Valves — Plunger Valve, Needle Valve, Sleeve Valve
For demanding water control applications, basic control valve options like globe valves might not be up to the task. In this case, specialty control valves such as plunger valves, needle valves or sleeve valves may be the ideal choice. These types of valves offer distinct advantages in terms of precision and control.
Plunger valves, for instance, are excellent for modulating flow across a broad operating range, as they can handle high pressure drops across the valve without significant wear. Plunger valves direct the flow of liquids to the center of the flow element. This results in cavitation or implosions taking place in the center of the flow stream, away from adjacent pipe and valve surfaces. Plunger valves are commonly found in pumping applications with variable operating requirements.
Needle valves allow for minute flow adjustments and are ideal for applications requiring precise flow regulation, however these valves are particularly suited to low flow applications. Needle valves may be found in auxiliary water control systems, for example they may form part of the hydraulic control circuit of pressure reducing valves.
Sleeve valves are particularly suited to situations that require a large pressure reduction, or discharging water at a high capacity. These valves are also used as energy dissipating valves, discharging to atmosphere. As such, sleeve valves are commonly found at dam and reservoir outlets, providing a controlled discharge of water.
Safety Valves for Water
The importance of safety valves in water systems cannot be overstated. Safety valves may be used to regulate the flow, pressure and temperature of water systems to ensure reliable and safe operation. They may also be used to redirect or stop the flow of water in a safe and controlled manner, mitigating and safety concerns.
Safety Relief Valve
A safety relief valve is a safety device that helps main safe working pressure in a system. It works by releasing excess pressure from a system, as soon as the pressure in the valve reaches a preset limit. This is crucial in preventing damage to pipework, equipment and fittings. Safety relief valves are found in industrial, commercial and residential water applications.
Safety relief valves come in various forms and functions, including pressure relief valves, steam relief valves, and temperature relief valves, each designed for specific scenarios depending on your requirements.
In industrial settings, for example, they protect against risks associated with high-pressure water systems. In homes, they are nearly always found in water heaters, ensuring that temperature and pressure remain within a safe operating range.
Safety relief valves are a broad topic in their own right. Common types of safety relief valves include spring-loaded, pilot-operated, piston and diaphragm type relief valves. Each of these valves are suited to particular applications.
Specifying and selecting a safety relief valve involves several factors. Material and connection types are typically specified to ensure compatibility with a particular system. The valve material is based on the process fluid and operating details. The valve material should be well suited to the intended application, whether it's steam, hot water, or high pressure potable water. Common materials include bronze, brass, cast steel and stainless steel.
Pressure rating and valve sizing are other critical factors, as the valve must be capable of handling the system's maximum operating pressure at the required capacity. Compliance with industry standards ensure that quality and reliability are considered, with the relevant certifications in place. Certifications are extremely important as they provide assurance that valves have been adequately tested and are proven to work safely.
Regular inspections and maintenance of safety relief valves are essential to ensure they function correctly when needed. Over time, these valves can wear out or become clogged with debris, which can impair their ability to release pressure effectively. Periodic testing of safety relief valves is strongly recommended.
Safety Relief Valve [ Image Link]
Backflow preventers
A backflow preventer is an essential device in pipelines with cross-connections. Backflow preventers are designed to ensure that water flows in one direction only, preventing unwanted reverse flow. This is crucial in keeping potable water systems safe and free from contaminants that may be drawn back into the clean water supply. Backflow preventers are commonly used in various settings, from residential homes to large industrial facilities.
You might be thinking, doesn't a check valve do the same thing? Well, only to an extent! A check valve is much less reliable than a backflow preventer. For instance, a check valve may fail open if something becomes lodged between the ball or disc and the valve seat.
A backflow preventer incorporates two (or more) check valves, which are controlled by a pressure-sensing diaphragm. It also includes a dead space where water is trapped until pressure is equalized on both sides. This is a fail-safe measure to divert fluid through a relief valve, should a check valve fail.
Backflow preventers come in several types, each suited for different applications and levels of protection. Some types of backflow preventers include Atmospheric Vacuum Breakers (AVB), Pressure Vacuum Breaker (PVB), Double Check Valve Assembly (DCVA) and Reduced Pressure Zone Assembly (RPZA). If you'd like more information about different backflow preventers, take a look at this blog.
RPZ Backflow Preventer [ Image Link]
Choosing the Right Water Valve
Choosing a water valve depends on your project specific needs. Bulk water transfer schemes and residential plumbing systems use different valve types, sizes, end connections and material combinations. Additionally, factors such as pressure requirements, temperature range and operating environment are important considerations.
Before specifying or purchasing a valve, it’s wise to consult a valve specialist or a trusted valve supplier. This will help ensure your valve meets all safety standards and functionality requirements for your system. Remember, selecting the correct valve guarantees efficient fluid control, extends the longevity of your piping system, reduces downtime and minimizes maintenance costs.
So, there you have it, a succinct yet hopefully informative review of valves commonly used in water applications. If you have any questions, or would like to know more about anything valve-related, don't hesitate to get in touch with our team at ValveMan.
Russ Bailey is a seasoned professional with an impressive 35-year career in valve sales. He serves as an Outside Sales Representative for both ValveMan.com and FS Welsford, where his deep industry knowledge and exceptional salesmanship enable him to provide tailored solutions for a diverse clientele. Russ is known for his ability to build robust relationships and his unwavering dedication to customer satisfaction. With a strong commitment to excellence, Russ continues to drive business growth and contribute significantly to the success of both companies.
