We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Machinery

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is a Valve Assembly?

By Paul Scott
Updated: May 17, 2024

A valve assembly is a complete valve mechanism including all peripheral devices directly related to the installation and functioning of the valve. The term may be applied to all valve types, including gas or fluid flow control valves and internal combustion engine valves. A valve assembly typically includes the entire fluid control mechanism and its casing, electrical or mechanical actuation mechanisms, and any related connectors, external sensors, and fasteners. In some cases, valve assemblies are supplied with ancillary devices, such as mounting adapter sets, shim selections, and spare seals.

In fluid and gas system flow terms, a valve is understood to be any mechanical device used to stop, start, or throttle a flow of fluid or gas through a system. In this sense, "throttle" refers to the act of controlling the extent of the flow. In these applications, "valve assembly" is a collective term used to describe the entire valve mechanism and all parts that play a direct, physical role in its actuation, operation, and control during operation. Valve assemblies are generally purchased complete to ease the process of replacement, but may, in the case of larger valves, be ordered on a part-for-part basis to reduce costs.

The main component in any valve assembly is the fluid or gas control mechanism and its casing where relevant. In some applications, this may be as simple an entity as an internal combustion engine valve, while, in others such as gate, ball, or butterfly types, a complex arrangement of parts encased in a external casing known as the valve body. In the case of a manually-actuated valve, the actuation mechanism will usually be an integral part of the main valve body. If the valve is automated, the second component in the assembly will be the actuator. This may be an electric motor, hydraulic or pneumatic unit, or a solenoid, along with all related hose or electric connections and cables.

Depending on the nature of the application, the valve assembly may also include external controllers such as stop/start stations and travel limit sensors. Valve specific fasteners such as grub screws, bolts, and circlips will also be included in the valve assembly description. Any ancillary equipment necessary for the installation and operation of the valve such as thread and flange adapters would also be considered to be part of the valve assembly and are often supplied as standard accessories. In the case of tappet-type valves, sets of valve shims may also be included. These peripherals will often also include replacement parts for high-wear parts of either the internal or external mechanisms, including spare O-rings, bushes, or seal elements.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
Share
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.