# Different types of classification of valves **URL:** \ **Category:** Valves\ **Created:** [July 25, 2018, 1:19pm UTC](https://forumautomation.com/t/different-types-of-classification-of-valves/4224 "2018-07-25T13:19:47Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![areejsidhik](https://forumautomation.com/letter_avatar_proxy/v4/letter/a/ee59a6/32.png) [@areejsidhik](https://forumautomation.com/u/areejsidhik)\ **Post date:** [July 25, 2018, 1:19pm UTC](https://forumautomation.com/t/different-types-of-classification-of-valves/4224/1 "2018-07-25T13:19:47Z")
In order to simplify the selection and specification of a device with such a broad definition, valves are traditionally classified according to one or more of the following factors ![1](https://cdn.forumautomation.com/original/2X/6/605402f22d3225e29a6fd9e61fc7a4111cef3853.jpg) > ## Classifying Valves according to Function ## 1.On/Off Valves • Used in applications where media must be diverted, in non-critical mixing, and in safety management systems • Most are hand-operated, although they can be automated with the addition of an actuator as seen in the photo of an Optimux OpTE herein Common On/Off Valves Include: • Gate • Plug • Ball • Pressure Relief ![1](https://cdn.forumautomation.com/original/2X/9/94ff9ac0a5bc5d043a6ce3a1c381c7dbbca2b8ea.jpg) ## 2.Non-return valves Non-return valves allow fluid to flow in only the desired direction; any flow or pressure in the opposite direction is mechanically restricted from occurring • Used to prevent backflow of fluid that could damage equipment or endanger the process • Particularly useful in protecting a pump in liquid applications or a compressor in gas applications Common Non-Return Valves Include: • Check valves ![1](https://cdn.forumautomation.com/original/2X/b/b7fa6a6e1f1f49e4f1f0807b23c53eb4e2438593.jpg) ## 3.Throttling valves Throttling valves are used to regulate the flow, temperature, or pressure of a service; can move to any position within the stroke, including full-open or fullclosed positions • Can also act as on/off valves • Many are hand-operated, but some are equipped with actuators, which provide greater thrust and positioning capability as well as automatic control Common Throttling Valves Include: • Pressure Regulators • Control Valves ![1](https://cdn.forumautomation.com/original/2X/e/ea0b36c59e0eaa4ee521c2ce899cbb380187cb5a.jpg) ## 4.Final Control Element Final Control Element refers to the high-performance equipment needed to provide the power and accuracy to control the flowing medium to specific service conditions • Part of the control loop, which consists of at least two other elements besides the control valves: • Sensing element • Controller • Control valve makes a change automatically, based on a signal from the controller, and the sensor measures and verifies the change • Control valves are the most common final control element ![1](https://cdn.forumautomation.com/original/2X/7/787931ee6ffb4a566b761a9c75c8b3ab2bffcc1a.jpg) > ## Classifying Valves according to Service ## General Service General service valves are those designed for the majority of commonplace applications with lower pressure ratings ![1](https://cdn.forumautomation.com/original/2X/2/24043601696bdff150d5d9e8523fa2bf15e011b1.jpg)• Lower ANSI Class: 150 - 600 • Moderate Temperature: -50 – 650°F • Noncorrosive fluids • Minimal Pressure Drops • No cavitation • No flashing • Carbon or Stainless Steel • Interchangeable and common to a wide variety of applications ## Special Service Special service valves are custom-engineered and designed for a single application outside normal process applications ![1](https://cdn.forumautomation.com/original/2X/a/abd6286763fda9e731f91230faabb7b5e73937f1.jpg)• High pressures • Demanding temperatures • Corrosive fluids • Minimal to Moderate Pressure Drops • Mild cavitation • No flashing • Special materials • Unique applications ## Severe Service Severe service valves are fitted with special features to handle extreme applications, such as high pressure drops that result in severe cavitation, flashing, choking, or high noise levels ![1](https://cdn.forumautomation.com/original/2X/8/8febffbc261809f901e371513929a48b5caf06c6.jpg)• High pressures • Extreme temperatures • Corrosive fluids • Severe Pressure Drops • Cavitation • Flashing • Choking • Noise • Custom-engineered trims aimed to prevent or reduce effects of service • Unique applications > ## Classifying Valves according to Motion ## Linear Linear valves have a sliding-stem that pushes a closure element – any internal device that is used to open, close, or regulate the flow – into an open or closed position • Simple design • Easy maintenance • Versatility in: • Sizes • Pressure classes • Design options ![1](https://cdn.forumautomation.com/original/2X/0/0d45b6522b41470d650949acbd11129a7efd82a7.jpg)Common linear valve styles: • Gate • Globe • Pinch • Diaphragm • Split-body • Three-way • Angle ## Rotary Rotary valves use a closure element that rotates – through a quarter-turn or 45° range – to open or block the flow ![1](https://cdn.forumautomation.com/original/2X/6/6503c1e9f5434b6a4a316390f8687cdfd58a32cc.jpg)• Larger port compared to linear valves of similar size • Weigh less than linear size-for-size • Limited in applications with pressure drops • Prone to cavitation and flashing • Often less costly **Also read** **[Basics of Control Valves and Parts of Control Valve](https://forumautomation.com/t/basics-of-control-valves-and-parts-of-control-valve/392)** To know more about control valves check the link below **[https://automationforum.co/category/valves/](https://automationforum.co/category/valves/)** ---
**Author:** ![Rachana\_Singh](https://forumautomation.com/user_avatar/forumautomation.com/rachana_singh/32/6870_2.png) [@Rachana\_Singh](https://forumautomation.com/u/Rachana_Singh)\ **Post date:** [April 24, 2023, 10:26am UTC](https://forumautomation.com/t/different-types-of-classification-of-valves/4224/2 "2023-04-24T10:26:18Z")
Great post! Valves are such an important component in many industries, and it’s essential to have high-quality options to ensure optimal performance and safety. I appreciate your insights on the different types of valves and how they function. I work in the oil and gas sector, and I can attest to the critical importance of reliable valves in our operations. Thanks for sharing this informative content!"