Questions You Should Know about Other Valve Related Components

Author: Justin

Jul. 21, 2025

Valve Components: Here's What You Must Know - MTM Hydro Parts

Those seemingly simple valves employ a lot of physics inside those metal bodies of theirs. What you may think of as a simple open-and-close system is about to be a bit trickier than you thought. In this post, we’ll talk about the most important valve components and their functions.

Goto YIYUAN to know more.

If you’re an automotive detailer or industries from industrial and residential cleaning who’s trying to understand more about valves, you’ll find this post useful. 

You’d also be happy to know that our shop at MTM Hydro powered by Veloci has more than what you need. Let us know if you have any questions, and make sure to check the tips and tricks to keep our products safe. 


The Basic Valve: An Overview

A valve is a device that can regulate or control the flow of a fluid through pipes. For a device to be able to do that, it’ll need to withstand pressure, prevent fluid leaks, and have a mechanism that allows for fluid control. All of this leads to a plethora of components working together to provide the final result.

There are different types of valves out there. A few examples are:

  • Globe valves
  • Gate valves
  • Butterfly valves
  • Needle valve
  • Ball valves (sometimes referred to as plug valves)
  • Non-return valves
  • Diaphragm valves

Each of these valves controls the flow of fluids differently. Some of them share the same function but with a different design, like gates and globe valves. Nevertheless, there are a few basic components that are found in all valves. These are:

  • Body and bonnet
  • Disc and seat
  • Actuator
  • Stem
  • Packing
  • Trim

Valve Components: Explained

Here’s what each component does in detail: 

1. Body and Bonnet

The valve’s body is the valve’s main pressure boundary and the primary housing that contains all other parts of the valve.

The bonnet is the valve’s cover, making it another pressure boundary element. Some valves don’t have valve bonnets. Instead, the body is split into two parts that are threaded, bolted, or welded together. 

In some valves (like globe and stop check valves), the bonnet can have an opening where the valve stem passes, giving you access to the valve’s internal parts. This is useful when you need to repair any damage inside the valve. 

Together, the body and the bonnet resist the fluid pressure and, if properly constructed, should prevent any leakage. 

Valve bodies can be made into various shapes and from various materials depending on the intended use. Some of these include: 

  • Stainless steel
  • Bronze
  • Iron
  • Plastic

If the design includes a bonnet, the bonnet is often made from the same material as the body. 

2. Disc and Seat

The disc is the valve part that controls the water flow. As long as the disc is seated in place, it’ll be exposed to the full system pressure until the outlet is opened again and the disc leaves its place. 

Because of the constant pressure applied on discs, they’re often made from hard materials to resist wear.

The seat (sometimes known as the seal ring) acts as the disc’s seating surface. Not every design will have seal rings, as some of them have the body machined to act as the seating surface. 

3. Valve Actuator

The expression “close the water valve” that people use is practically incorrect. You don’t close the valve; you operate the actuator (also known as the handle) in a linear and rotary motion to close the valve.

When you use the actuator, you put the disc in or out of place, which, in turn, controls the fluid flow. 

Actuators could be manual handwheels or levers, but they could also be operated via motor operators, pneumatic operators, and hydraulic rams

Unlike the valve body, bonnet, and disc, the actuator is often outside the pressure boundary. The exception lies in some hydraulic or pneumatic cylinders. 

4. Stem

The stem is the connector between the disc and the actuator. When you operate the actuator, the stem puts the disc in or out of place to connect the fluid flow. Much like the actuator, it also lies outside the pressure boundary. 

Oftentimes, stems are forged and threaded or welded to the disc. This connection allows for some slight movement range to facilitate the disc’s seating on the seat or the valve’s body.

Some designs also manufacture the stem to be more flexible to allow the disc to position itself on the seat. However, these designs are more likely to damage the valve disc because of constant fluttering.

Note that stems have two types:

  • Rising stems
  • Non-rising stems

The difference between both types lies in the movement of the stem as the actuator is operated. 

Rising stem designs will have the stem screw above the actuator during usage. That rise is because the stem is threaded to a yoke that’s mounted to the bonnet. Alternatively, non-rising stems won’t rise above the actuator since the stem is internally threaded to meet the disc. 

5. Packing

Leakage can happen outside or inside the valve. The inside leakage is prevented by filling the space between the bonnet and stems with packing.

This packing can be composed of various materials like flax and teflon. The point is to seal the internal parts of the valve to minimize leakage.

6. Trim

The trim is a collective term used to describe all removable internal valve parts. These parts include:

  • Spacers
  • Discs
  • Valve seats
  • Guides
  • Springs

Valve Applications

The quickest example of using valves in most people’s minds is using a water tap valve. However, they can be utilized in many other clever manners. 

For example, car detailers often use consolidated guns and lance systems to clean cars. This system usually uses a three-way ball valve. However, this would result in a lot of dismantling, wasted time, and lost spray.

A smarter application would be to use a two-way shuttle valve that allows the user to keep both the nozzle and the foam cannon in one place. With a single click, the user can switch between water or foam. 

One of the latest wash systems that utilize this design is the Mezzo Wash System by MTM Hydro powered by Veloci

Contact us to discuss your requirements of Other Valve Related Components. Our experienced sales team can help you identify the options that best suit your needs.

Suggested reading:
Design Considerations for Successful Stainless Steel Investment ...

The Verdict

As an automotive detailer, understanding valve components is among the many things you need to learn. 

And if you’re looking for smart applications of valves and various other auto detailing equipment, make sure to check MTM Hydro powered by Veloci

Valves 101: Valve Types, Sizes, Standards & More - Unified Alloys

What Are Valves and How Do They Work? 

At their most basic, valves are devices that work to control, regulate or direct flow within a system or process.

They often feature a range of characteristics that help to define their ideal application.

However, whether you’re looking to control flow, provide safety in a system that is piping liquids, solids, gasses or anything in between, there are likely stainless steel valves available to help.

Valves provide several functions, including:

  • Starting or stopping flow based on the valve state
  • Regulating flow and pressure within a piping system
  • Controlling the direction of flow within a piping system
  • Throttling flow rates within a piping system
  • Improving safety through relieving pressure or vacuum in a piping system

Valve Opening Methods Explained

While many valves accomplish similar goals, how they do so mechanically can vary.

How a valve opens and closes will not only impact the overall performance but also determine how much control you have over the flow and how quickly the valve can operate.

Most valves fit into one of three categories:

  • Multi-Turn valves: Think of these valves like a screw or piston. You crank the handle and the plug, plate, membrane, or other controlling obstruction moves into the path of the pipe blocking access. Depending on the valve, these can have higher or lower differentials allowing you to open or close them at various speeds.
  • Quarter turn valves: Quarter-turn valves offer a full range of motion in a 90-degree turn of the handle. This makes them ideal for situations where precision isn’t as important as rapid action and easy opening or closing.

On top of the mechanical motion involved with a valve, also consider the method of actuation. In most cases, valves fall into one of three categories:

  • Manual Valves: Typically adjusted by hand, these valves use handwheels, hand levels, gear wheels, or chains to actuate.
  • Actuated Valves: Often connected to electric motors, air or pneumatic systems, hydraulic systems, or solenoids, these valves allow remote control and automation for high-precision or large-scale applications.
  • Automatic Valves: Some valves activate when a specific flow condition is met. Examples include check valves closing during backflow or pressure release valves activating when an over-pressure condition is detected.

Common Valve Types and Their Applications

Valves feature a range of characteristics, standards, and groupings the help to give you an idea of their intended applications and expected performance. Valve designs are one of the most basic ways to sort the huge range of valves available and finding a good fit for a project or process.

Common types of valves include:

You might also see valves classified by function instead of design.

Common functional designations and their common design types include:

  • Isolation Valves: Ball, butterfly, diaphragm, gate, pinch, piston, and plug valves
  • Regulation Valves: Ball, butterfly, diaphragm, globe, needle, pinch, and plug valves
  • Safety Relief Valves: Pressure release and vacuum relief valves
  • Non-Return Valves: Swing check and lift check valves
  • Special Purpose Valves: Multi-port, float, foot, knife gate, and line blind valves

Valve Sizing Explained: Keeping Things Flowing

While valves might be a small part of your piping process or system in terms of space, they’re often a substantial portion of the design and build budget. They also have a significant impact on long-term costs and overall system performance.

Choosing a proper valve size is essential to both optimizing costs and ensuring safe, accurate, and reliable operation.

The first thing to consider is the overall size of the valve -- both in terms of physical dimensions and in terms of internal size and flow rates (CV).

Choosing a valve that does not fit properly in the space required could result in added costs. Choosing a valve which does not provide the ideal flow rate can lead to inaccurate flow control at the least and complete system failure at worst.

For example, if your valve is too small, it could cause reduced flow downstream while creating back-pressure upstream. If the valve is too large, you’ll find that flow control is drastically reduced the further you move from fully open or fully closed.

When choosing the proper size, be sure to consider both the connector diameter and the overall flow rate of the valve compared to your needs. Some valves offer excellent flow while others constrict flow and increase pressure.

This means sometimes you must install a larger valve to adjust for flow than the adapter diameter alone might imply.

Valve End Connections: The Key to a Good Fit and Proper Operation

With sizing and design out of the way, it’s also important to consider valve end connections.

While the most obvious implication here is choosing an end connection compatible with your piping, there are also functional characteristics to common end types that might make one valve more suited to your needs than another.

Common valve connections and ends include:

  • Screwed or Threaded: Often used in instrument connections or sample points
  • Flanged: The most common ends for piping use
  • Butt Welded: Typically used in high-pressure or high-temperature operations
  • Socket Welded: Commonly used on small bore piping where threaded connections are not permitted
  • Wafer and Lug: Often used for compact valves installed in systems with limited space

Valve Materials: Ensuring Safety and Long-Lasting Performance

Depending on your intended use, the materials with which your valves are made might be a critical aspect in ensuring safe operation and reducing maintenance and replacement costs over the life of your operation.

Stainless steel valves are excellent options in a range of processing environments, including those involving corrosive media (such as chemicals, saltwater, and acids), environments with strict sanitation standards (such as food and beverage manufacturing and pharmaceuticals), and processes involving high pressure or high temperatures.

However, if you are processing solvents, fuels, or volatile organic compounds (VOCs), choosing a valve material from a non-sparking material -- such as brass, bronze, copper, or even plastic -- is often a better option. In addition to selecting the correct body material, internal (wetted) trim parts should be evaluated for chemical compatibility as well. If your valve contains elastomers, they should also be evaluated for their chemical compatibility as well as pressure and temperature limitations.

Valve Standards: Meeting Compliance and Regulatory Concerns

Depending on your intended usage, you might find that valves must adhere to particular standards to meet regulatory requirements for safety, sanitation, or other concerns.

While there are too many standard organizations and potential regulations to cover in detail, common general standard organizations include:

  • CSA Group (CSA)
  • The American Society of Mechanical Engineers (ASME)
  • The American National Standards Institute (ANSI)
  • The American Society for Testing Materials International (ASTM International)
  • The Manufacturers Standardization Society (MSS)
  • The International Organization for Standardization (ISO)
  • The Public Health and Safety Organization (NSF)
  • NACE International (NACE)
  • The American Petroleum Institute (API)
  • American Water Works Association (AWWA)

There are also industry-specific standards to consider.

Major standards organizations by industry include:

  • ASHRAE Valve Standards
  • ASME BPVC Valve Standards
  • ASSE Valve Standards
  • ISA Valve Standards
  • NFPA Valve Standards
  • SAE Valve Standards

Final Thoughts

Choosing the right valve for your project might seem complex. However, by starting with general characteristics -- such as valve design, valve size and actuation method -- you can quickly limit your options to determine the best valves for your needs.

Whether you’re designing a new processing system or looking to make upgrades to or maintain an existing system, Unified Alloys’ selection of valves and fittings can help you find the ideal solution for your application and usage environment. As a leading provider of stainless steel alloys, valves, flanges, and more, our experts have helped industries across Canada and North America for more than 4 decades. Need assistance or have a question? Contact us for personalized help.

For more information, please visit Valve Parts Components.

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