A valve serves as a mechanism or a naturally occurring element that orchestrates, steers, or commands the course of a fluid (whether it’s gases, liquids, fluidized solids, or slurries) by executing actions such as opening, closing, or partly obstructing diverse passages. Its operation relies on a movable component that can unveil, seal, or partially impede an aperture within a conduit. While there are generally seven fundamental types of valves, namely globe, gate, needle, plug (often referred to as a cock), butterfly, poppet, and spool valves, it’s noteworthy that the diversity in industrial applications has led to the utilization of a staggering 22 distinct types of valve worldwide. Valves manifest themselves ubiquitously across many industrial processes, spanning water and wastewater treatment, mining, electricity generation, oil and gas refinement, food production, chemical and plastics manufacturing, and many other sectors.
Table of Contents
Different Types of Valves
Types of Valves
- Ball Valves
- Gate Valve
- Globe Valve
- Butterfly Valve
- Check Valve
- Plug Valve
- Diaphragm Valve
- Needle Valve
- Pressure Relief Valve
- Safety Valves
- Control Valves
- Pinch Valve
- Solenoid Valve
- Knife Gate Valve
- Foot Valve
- Piston Valve
- Angle Valve
- Flush Bottom Valve
- Three-Way Valve
- Four-Way Valve
- Poppet Valve
- Float Valve
Main Types of Valves: Names & Functions
A gate valve, also known as a sluice valve, is a device used to control fluid flow in a pipe. It works by moving a barrier, called a gate, inside the tube to either open or close the passage for the fluid.
Its main job is to stop the flow of liquid entirely or, when fully available, allow fluid to move freely through the pipeline.
The parts of a gate valve include the main housing, seating arrangement, gate (obstruction element), mechanism to move the gate, sealing gland, and a manual control mechanism.
The seating arrangement and the gate work together to stop the fluid flow. Gate valves primarily shut off fluid flow, unlike globe valves, which focus more on regulating flow.
These valves prioritize simplicity and effectiveness over preventing minor leaks, ensuring they work well when needed.
A globe valve is a special valve used to control the flow of liquids in pipes over other types of valves. It has a round housing, a movable plug, and a fixed ring seat. Imagine a ball inside a cup – that’s the basic idea.
The “globe valve” name comes from its round shape and the inner part that blocks the flow. This inner part has a seat-like hole, with a flexible plug opening or closing the valve. This plug is connected to a rod.
Turning a handwheel spins the rod in manual valves, moving the plug to let the liquid through or stop it. In automatic valves, there’s a different system using smooth rods and an actuator to control the valve.
Even though older globe valves looked like a ball in a cup, newer ones might not. But we still call them globe valves because they work the same way inside.
In plumbing, people might also call them “stop valves.” This doesn’t mean they look the same, but they’re all designed to stop the flow. Remember that you can use a “stop valve” for any valve that halts the flow, regardless of its mechanism or appearance.
A Butterfly Valve is a unique control device used in big pipes for liquids and gases. It helps to control the flow of these substances. It works by turning a round piece inside the pipe a quarter of the way around. This round piece is connected to a stick that can be moved to turn it.
When the round piece turns, it can make the pipe fully open or fully closed. “It looks like a butterfly, earning it the name due to its resemblance. The round piece attaches to a stick that one can push to close the pipe completely.”
You can also use this valve to control the flow very precisely. Even when fully open, it loses some pressure because of the round piece in the way. This is different from a ball valve.
Plug valves are mechanical devices designed for fluid control within a pipeline. They feature cylindrical or conically tapered “plugs” positioned within the valve body, enabling flow regulation by rotation.
The valve’s operational configuration allows fluid passage through one or more horizontal tunnels in the plug while the valve is open. These valves are favored for their user-friendly attributes and cost-effectiveness.
Typically, the stem or handle of the plug valve attaches to the broader end of the conically tapered plug. Traditional bonnets are often absent when the plug has a conical taper & the handle externally or partially exposes it. The stem length may be minimal in such setups.
A fundamental and prevalent configuration of the universal plug valve is the 2-port design. It encompasses two positions: an open state that permits flow and a shut (closed) state that halts it.
A needle valve has a specialized design that includes a slender opening and a carefully crafted plunger with a needle-like thread. It is used when precise fluid flow control through the pipe is necessary.
These types of valves operate through the utilization of a tapered pin rotated gradually in a small orifice, allowing fluid to flow in a controlled manner. This critical component makes the needle valve work pleasing and allows a specific quantity of liquid to pass through the pipe.
This valve has two main parts: a small hole and a unique plunger that fits inside it. Rotating the screw causes the plunger to traverse the aperture, but the fluid flow remains constrained until the plunger travels a specific distance.
Multiple turns of the screw are often required to open the valve and fully achieve the desired flow rate.
Remarkably, even the slightest movement of the pin within the needle valve induces a precise alteration in the flow rate. It is because of the unique design of the pin and the hole.
People commonly use these valves in applications that require precise control over gas flow, such as vacuum tubes, gas lasers, and various systems that operate with low-pressure gases.
A control valve is a pivotal component in fluid flow management, effectively altering the flow passage’s dimensions under the command of a controller-derived signal. This capability facilitates precise regulation of flow rates, thereby exerting direct authority over process attributes like pressure, temperature, and liquid levels.
A control valve is a “final control element within automatic control terminology.” The produced actuation of control valves primarily involves electrical, hydraulic, or pneumatic actuators, whether for opening or closure.
An automatic control valve has three main parts, and each part comes in different types and setups:
- Valve Actuator: This dynamic element imparts motion to the valve’s modulating entity, exemplified by structures like balls or butterflies.
- Valve Positioner: This element assures the valve’s alignment with the intended degree of openness. This strategic inclusion serves to surmount challenges emanating from factors like friction and attrition.
- Valve Body: Central to the assembly, this segment accommodates the modulating entity, which can manifest as a plug, globe, ball, or butterfly.
A safety valve is a critical component engineered to operate as a fail-safe mechanism. One illustrative embodiment of such a safety valve is the pressure relief valve (PRV), meticulously designed to autonomously disengage a substance from within a boiler, pressure vessel, or analogous system upon breaching predetermined pressure or temperature thresholds.
Another specialized type is the pilot-operated relief valve, which offers a unique way of operation. In emergencies, a leak-proof and cost-effective alternative is the rupture disk.
The history of safety valves can be traced back to their initial use in steam boilers during the Industrial Revolution. The absence of these devices made early boiler systems prone to catastrophic explosions, highlighting their vital importance.
Expanding on this topic, vacuum safety valves, also known as combined pressure/vacuum safety valves, prevent tanks from collapsing during evacuation or after thermal processes like clean-in-place (CIP) or sterilization-in-place (SIP).
In technical terms, a poppet valve, sometimes called a mushroom valve, is an important part that controls the flow of gas or vapor in various machines. It looks like a round or oval hole connected to a stick called a valve stem, which ends in a disk-shaped block known as the valve plug.
The block’s flat part, the valve face, is carefully ground at a 45° angle to create a tight seal against a matching seat around the hole, ensuring an airtight closure. The valve stem moves in a guide to stay straight as it works.
How well the poppet valve works depends on the pressure difference between its two sides. In exhaust systems, higher pressure helps it seal better, while lower pressure makes it easier to open in intake systems.
Common Types of Valves: Names & Functions
A ball valve is a pivotal flow modulation apparatus overseeing the movement of fluids through a perforated, hollow sphere.
Its operational mode involves an open configuration when the central bore of the globe aligns with the inlet flow, while a 90-degree pivot of the valve handle results in the closure, obstructing the passage.
The handle’s orientation parallels the flow in the open state and stands perpendicular when shut, affording a facile visual means of ascertaining the valve’s status. The quarter-turn shut position can be executed in the clockwise or counterclockwise direction.
The ball valve’s intrinsic user-friendliness, reparability, and adaptability render it a fitting choice across a broad spectrum of industrial applications, accommodating pressures reaching up to 1,000 bar (100 MPa; 15,000 psi) and temperatures soaring to 750 °F (400 °C), contingent upon the specific design and materials employed.
Within typical dimensions spanning 0.2 to 48 inches (5 to 1200 mm), the valve bodies materialize in metal, plastic, or hybrid compositions of metal and ceramic. Floating balls are frequently veneered with chrome to enhance their durability.
The ball valve bears the drawback of entrapping water within the central cavity when in the closed position. In subzero temperatures, the enclosure walls are susceptible to fracturing due to the expansion associated with ice formation.
A check valve, recognized as a non-return valve, embodies a unidirectional fluid control mechanism pivotal in constraining fluidic progression to a sole vector. Its function resides in impeding retrogressive flow within a given system.
Check valves, which seem like bidirectional ports, have a dual orifice arrangement, with one aperture accommodating fluid admission and the other egress.
A spectrum of check valve variants finds deployment across an extensive gamut of applications, permeating even the fabric of commonplace domestic paraphernalia.
Diverging in dimensions and cost, the intrinsic nature of check valves predominantly skews toward compactness, simplicity, and economic viability.
The autonomic operability characteristic to check valves obviates the requirement for human intervention or extrinsic regulation, thereby preventing the need for manual manipulation such as valve handles or stems.
The constitution of check valves predominately revolves around materials like polymers or metals, encapsulating their outer casings.
A diaphragm or membrane valve encompasses a valve body distinguished by its arrangement of two or more ports. A flexible diaphragm assumes a pivotal role within this valve structure.
This diaphragm interacts with a distinctive “weir” or seat, affecting valve closure. The composition of the valve body can vary, encompassing materials such as plastic, metal, wood, and other tailored substrates.
Typically configured as 2/2-way diaphragm valves with two ports, these valves can expand to encompass three ports in the form of 3/2-way diaphragm valves (commonly termed T-valves), four ports as block valves or even a higher number.
Diaphragm valves offer a contradiction of operational modes: manual and automated. These types of valves are amenable to equipping with an array of supplementary components. Solenoid valves, limit switches, and positioners augment their pneumatic, hydraulic, or electric actuators.
This amalgamation of technologies refines and customizes valve performance to meet specific operational exigencies.
Pressure Relief Valve
It is crucial to use a relief valve to prevent problems like equipment breakdowns, explosions, or fires, often called a pressure relief valve (PRV). This device helps maintain the correct pressure in systems by safely releasing excess pressure. By setting a specific pressure level, the relief valve prevents pressure vessels and equipment from getting stressed.
When the pressure exceeds the set limit, the relief valve becomes the main path, letting some pressurized fluid escape through a different route. In the case of flammable fluids, operators carefully burn off the redirected substance, whether it is gas, liquid, or a mix, in a designated elevated gas flare.
This controlled burning process releases combusted gases into the air or directs them through special pipes known as a flare or relief header. Afterward, a high-capacity vapor recovery system collects the effluent using a low-pressure, high-flow method.
The term “blowdown” refers to how much the pressure must drop for the valve to reset, usually expressed as a percentage of the preset pressure. Some valve types allow operators to customize blowdowns within 2% to 20%, depending on the specific system requirements.
Pinch valves represent a clever advancement in fluid control technology. Their operation hinges on the interaction between a flexible tube, often a sleeve or hose, and a valve body component. By exerting pressure on the tubing, a seal is formed that simulates the properties of the tube material itself.
The system comprises a reinforced rubber hose, a specialized housing, and two socket end covers or flanges for air-operated pinch valves. The meticulous process of assembling these components ensures a secure fit for the hoses and correct alignment within the housing using the socket covers.
What adds to their intrigue is the absence of an external actuator requirement. These valves automatically close when pressurized air is introduced into the valve body.
Conversely, stopping the air supply allows the trapped air within to dissipate, and the inherent elasticity of the rubber hose causes it to expand gradually. Pinch valves simplify fluid control with their uncomplicated design and automated functionality.
A solenoid valve is an electrically controlled valve that uses electricity to regulate the flow of fluids such as water or gases. These types of valves come in various designs to fit different applications.
Some solenoid valves operate linearly, moving back and forth like a plunger, while others pivot, resembling an arm or a rocker. They have two ports to control flow. Complex fluid systems are created by combining multiple solenoid valves into a single unit.
Solenoid valves are very versatile and are employed across various industries. They serve functions like stopping, releasing, measuring, mixing, or separating liquids and gases. They are well-known for their speed, reliability, and energy efficiency. Also, they perform effectively with a wide range of fluids, boasting a long lifespan.
Solenoid valves are available in multiple designs. The simplest ones feature two ports that either allow fluid to flow when activated (“normally open”) or block it when not in use (“normally closed”). A 3-way valve that connects one port to two others is frequently used in supply and exhaust systems.
Knife Gate Valve
Knife gate valves are similar in structure to regular gate valves, initially designed for use in the pulp and paper industry. They get their name because they are good at handling dense, particle-filled substances that often make it hard for valves to close properly and prevent leaks.
These valves are used explicitly as isolation valves and are suitable for situations where the conveyed fluids are not hazardous, like wastewater. One key feature is their smooth and unobstructed passage, allowing easy maintenance using a cleaning device.
While there isn’t much pressure difference across these valves, they can experience vibrations or “chatter” during operation due to fluid forces interacting with the gate. However, this matters little because knife gate valves are primarily designed for complete closure or whole opening, not for fine flow control.
Here’s how they work: a slim stainless-steel gate moves up and down in the valve’s bore, controlled by a spindle or threaded mechanism. Unlike traditional gate valves, this gate moves externally to the valve body. Guide and seal mechanisms combine around the bore’s edge to create a tight seal that prevents gas leaks.
It’s important to note that gate and knife gate valves primarily serve the purpose of isolating flow and work best in situations where you need to completely turn the flow on or off rather than gradually adjusting it.
Foot Valve – Types of Valves
A foot valve is a particular type with a filter attached to one end. It’s mainly used when liquids need to be lifted from lower levels, like in pump systems or pipelines. The main job of a foot valve is to help pumps work better by letting liquid in but stopping it from flowing back.
One nice thing about foot valves is that they let the liquid flow quickly and don’t slow things down too much. They only let the liquid go in one direction and close promptly to stop any reverse flow. The filter attached to the valve also helps catch any solid bits in the liquid so the valve doesn’t get clogged.
When pumps are used to move liquids up, they need energy. And when the pumps stop, the fluid can try to flow back down.
But foot valves are smart because they stop this from happening. They keep the liquid from going back down, which helps keep things running smoothly even when the pump is off.
These types of valves govern fluid flow within a conduit or pipeline through a rectilinear piston displacement ensconced within a dedicated chamber or cylinder.
Noteworthy illustrations encompass the valves integral to numerous brass instruments, those employed in pneumatically driven cannons, and those found within many fixed steam power plants and steam-driven locomotives.
Angle Valve – Types of Valves
An angular valve, often called a “stop valve,” is a manual valve that controls or stops liquid flow in pipes. It has ports that are at right angles to each other. You can recognize it by its oval knob or handle.
People commonly find these valves in homes and industries, where they use them to regulate water flow. Some of these valves have removable handles to prevent tampering.
In the past, you had to turn the handle many times to stop the flow completely, but modern ones only require a quarter-turn for quick shutdown during emergencies.
You see these valves in everyday places, like toilets and faucets. They allow you to fix or replace these fixtures without turning off water to the whole building. It is convenient for smaller repairs.
These valves are also crucial in emergencies like leaks or pipe bursts. Turning them off fast stops more water from getting to the damaged area until it can be fixed.
Flush Bottom Valve
The flush bottom valve, recognized under alternative names such as angle bottom, tank, flush mount, and bottom drain valves, is pivotal in diverse industrial applications. This valve configuration is meticulously engineered to achieve dead space-free closure within vessels, reactors, storage tanks, and autoclaves.
Its function involves facilitating the drainage of substances characterized by semi-solid consistency, viscosity, slurry composition, and abrasiveness.
Flush bottom valves span a size spectrum ranging from 15mm to 150mm, accommodating various industrial contexts. The construction of these valves entails a meticulous selection of materials, including cast iron and stainless steel.
The seating composition, encompassing materials such as neoprene, Viton, and Teflon, are critical elements influencing valve performance. The type of seat material you use depends on the task to make sure it works well and lasts a long time.
Three-Way Valve – Types of Valves
A three-way valve is a unique tool for controlling liquids moving through three openings. It’s not like the usual valves you see because it can change the path of the fluid.
Imagine it has three parts: where the liquid comes in (A), where it goes out (B), and a place in the middle (C) that can change things up.
There are two main types: one looks like a “T,” and it connects three pipes to mix or separate liquids. The other looks like an “L,” which joins only two pipes to give out fluids.
When the valve opens, the liquid goes in through A and B. But when we want to send the liquid somewhere else, we use a particular part called an actuator.
This actuator moves the middle part, and now the liquid comes in through A and goes out through C, changing its path. And when we want to stop the flow, we use the actuator again to close the valve. That’s how a three-way valve works.
A four-way valve, also called a four-way cock, is a special valve used to control the flow of fluids. It has four openings around it. The valve’s part that goes inside has paths that connect these openings in different ways. This part can look like a cylinder, cone, or ball.
This valve has two prominent flow positions and a middle position where all openings are closed. It’s handy when you need to isolate and divert a sample container attached to a pressurized water pipe.
It lets you take fluid samples without affecting the pipe’s pressure. The valve design also prevents gas from escaping and keeps the fluid pure.
The unique paths inside the valve that don’t connect directly are sometimes called “×” ports. It emphasizes the valve’s unique shape.
Float Valve – Types of Valves
A float valve is a device that helps control liquid levels, like a water level controller. It uses a floating mechanism to sense if the fluid level is too high or low and then opens or closes a valve to adjust it. In homes, smaller float valves can regulate tank water levels and control hot water system pressure.
They come in “low pressure” and “high pressure,” suitable for different water pressure conditions. These valves are made from brass, bronze, or plastic and manufactured using casting or injection molding.
In larger refrigeration systems, float valves play a vital role. They act as exceptional levers to manage liquid levels in complex setups, ensuring everything runs smoothly. Their precise control is crucial for efficiently operating these refrigeration systems, making them essential components.