{"id":12305,"date":"2021-12-02T10:00:45","date_gmt":"2021-12-02T18:00:45","guid":{"rendered":"https:\/\/www.linquip.com\/blog\/?p=12305"},"modified":"2026-02-27T11:05:10","modified_gmt":"2026-02-27T19:05:10","slug":"working-principle-of-control-valve","status":"publish","type":"post","link":"https:\/\/www.linquip.com\/blog\/working-principle-of-control-valve\/","title":{"rendered":"Working Principle of Control Valve with Diagram"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_83 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.linquip.com\/blog\/working-principle-of-control-valve\/#Basics_of_Control_Valves\" >Basics of Control Valves<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.linquip.com\/blog\/working-principle-of-control-valve\/#Operation_of_Control_Valves\" >Operation of Control Valves\u00a0<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.linquip.com\/blog\/working-principle-of-control-valve\/#Parts_of_Control_Valves\" >Parts of Control Valves\u00a0<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.linquip.com\/blog\/working-principle-of-control-valve\/#Download_Working_Principle_of_Control_valve_PDF\" >Download Working Principle of Control valve PDF<\/a><\/li><\/ul><\/nav><\/div>\n<p><span style=\"font-weight: 400;\">The working principle of control valve is opening or closing internal passages in order to regulate the flow of a liquid or gas. Control valves are part of a control loop that controls a process. Control valves adjust internal openings in response to instructions from the controller.<\/span><\/p>\n<p>The control valve is the last control component that is used the most frequently in process control sectors. To counteract the load disturbance and maintain the regulated process variable as close to the intended set point as feasible, the control valve modifies a flowing fluid, such as gas, steam, water, or chemical compounds. There are multiple <a href=\"https:\/\/www.linquip.com\/industrial-directories\/352\/control-valve\/for-sale\"><strong>Control Valves for Sale on Linquip<\/strong><\/a>, and control valves are offered by a range of Suppliers &amp; Businesses, manufacturers, and <a href=\"https:\/\/www.linquip.com\/suppliers-companies\/distributor?category_id=352&amp;cn=control-valve\"><strong>Distributors<\/strong><\/a>.<\/p>\n<p>There is a complete list of valve services on the Linquip platform that covers all OEM fleets. Please call <a href=\"https:\/\/www.linquip.com\/experts?q=control-valve\"><strong>Control Valve Experts<\/strong><\/a> in Linquip to learn more about how to connect with a diverse group of <a href=\"https:\/\/www.linquip.com\/suppliers-companies\/service-provider?category_id=352&amp;cn=control-valve\"><strong>Service Providers<\/strong><\/a> who consistently deliver high-quality products.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Basics_of_Control_Valves\"><\/span><b>Basics of Control Valves<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The control <\/span><a href=\"https:\/\/en.wikipedia.org\/wiki\/Valve\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">valve<\/span><\/a><span style=\"font-weight: 400;\"> is used for controlling fluid flow by changing the size of the flow passage according to the controller and enabling direct control over the flow rate. This results in controlling process quantities such as liquid level, temperature, and pressure. In automatic control terminology, it is called the final control element. Based on controller input, control valves are able to control fluid flow rates.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Control valves can be used to regulate pressure and\/or flow rate automatically, no matter which pressure is used. In some cases (as determined by design), different plant systems may operate at pressure and temperature combinations that require Class 300 valves, so all control valves are usually Class 300 for interchangeability. As long as the system does not exceed the rating for the Class 150 valves, this is not necessary.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Control valves are normally globe valves whose ends are flanged to facilitate maintenance. Depending on the type of supply, the disk can be moved by hydraulic, <\/span><a href=\"https:\/\/en.wikipedia.org\/wiki\/Pneumatics\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">pneumatic<\/span><\/a><span style=\"font-weight: 400;\">, mechanical, or electrical actuators. A valve modulates flow by moving a valve plug in relation to the valve body&#8217;s port(s). Valve plugs are attached to valve stems, which, in turn, are attached to actuators.<\/span><\/p>\n<h3><strong>What Is the Application of Control Valve?<\/strong><\/h3>\n<p>A control valve is one that, as the name suggests, is used to control something. Controlling flow, temperature, pressure, or liquid level is a typical application for control valves. A control signal, which might be hydraulic, electric, or pneumatic, opens and closes the control valve.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Operation_of_Control_Valves\"><\/span><b>Operation of Control Valves\u00a0<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The process control industry includes control valves as the final control element. Control valves manipulate fluids, such as water, gas, steam, or chemical compounds, to compensate for load disturbances, keeping the regulated process variable as close to the desired set point as possible.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Typically, automatic control valves are opened or closed by electrical, hydraulic, or pneumatic actuators. When a modulating valve can be set anywhere between fully closed and fully open, valve positioners are normally used to ensure that the valve achieves the desired degree of opening.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The simplicity of air-actuated valves makes them popular, as they are only powered by compressed air, as opposed to electrically-operated valves, which require additional cabling and switch gear, and hydraulically-actuated valves, which require high-pressure fluid supply and return lines.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Control signals for pneumatic systems are typically based on a pressure range of 3 to 15 psi (0.2 to 1.0 bar) or, typically, on a 4-20mA electrical signal for industry or a 0-10V signal for <\/span><a href=\"https:\/\/en.wikipedia.org\/wiki\/Heating,_ventilation,_and_air_conditioning\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">HVAC<\/span><\/a><span style=\"font-weight: 400;\"> systems. Today, electrical control often includes a smart communication signal that can be superimposed over the 4-20mA control signal, allowing the controller to monitor and signal valve health and position back to the controller.<\/span><\/p>\n<figure id=\"attachment_12307\" aria-describedby=\"caption-attachment-12307\" style=\"width: 431px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"size-full wp-image-12307\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/Structure-of-pneumatic-control-valve.jpg\" alt=\"working principle of control valve\" width=\"431\" height=\"423\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/Structure-of-pneumatic-control-valve.jpg 431w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/Structure-of-pneumatic-control-valve-300x294.jpg 300w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/Structure-of-pneumatic-control-valve-428x420.jpg 428w\" sizes=\"(max-width: 431px) 100vw, 431px\" \/><figcaption id=\"caption-attachment-12307\" class=\"wp-caption-text\">Schematic overview of the structure of pneumatic control valve (Reference: <strong>researchgate.net<\/strong>)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">One of the most important but also most neglected parts of a control loop is the control valve. Most of the problem comes from instrument engineers&#8217; limited knowledge of facets, terminologies, and areas of engineering disciplines such as metallurgy, fluid mechanics, noise control, and plumbing, as well as vessel design, which may be involved depending on the severity of the service requirements.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Control loops usually consist of a process condition sensor, a transmitter, and a controller that compares the received &#8220;process variable&#8221; to the &#8220;set point,&#8221; i.e. desired process condition. The controller, in turn, transmits a corrective signal to the &#8220;final control element,&#8221; the last component of the loop and also the &#8220;muscle&#8221; of the process control system.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A control loop is considered to be made of three parts, the eyes, which are sensors of the process variables; the brain, which is the controller; and the hands, which are the final control element. Consequently, it is the most vital, but sometimes least understood, component of an automatic control system. In part, this occurs since we are so enamored with electronic components that we neglect to fully understand and utilize all-important hardware elements.<\/span><\/p>\n<h3><strong>What Are the Characteristics of Control Valve?<\/strong><\/h3>\n<p>Although certain other intrinsic valve features, including parabolic, modified linear, or hyperbolic, are occasionally employed, quick opening, linear, and equal proportion valves are the most often manufactured. Each application&#8217;s installation will have a special feature that links fluid flow to heat demand.<\/p>\n<h3><i><span style=\"font-weight: 400;\">Arrangement of Control Valves\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">The following image illustrates how the flow rate in a line can be controlled using a control valve. A &#8220;controller&#8221; receives pressure signals and compares them with the desired flow. If the actual flow varies from the desired flow, the control valve adjusts to overcome the difference. It is possible to control any one of a number of process variables in a similar manner. The most commonly controlled variables are temperature, pressure, level, and flow rate.<\/span><\/p>\n<figure id=\"attachment_12308\" aria-describedby=\"caption-attachment-12308\" style=\"width: 820px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"size-full wp-image-12308\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/cvalvesystem.gif\" alt=\"working principle of control valve\" width=\"820\" height=\"384\" title=\"\"><figcaption id=\"caption-attachment-12308\" class=\"wp-caption-text\">Control valves arrangement (Reference: <strong>steamline.com<\/strong>)<\/figcaption><\/figure>\n<h3><i><span style=\"font-weight: 400;\">Control Valve Problems\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">It is possible that control valves fail to regulate the parameter they are controlling properly. Quality issues arise when the process is not controlled.<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">There is a possibility of oversizing control valves. When fine adjustments are needed, an overly large control valve is insensitive and wastes money. The control valve is usually one or two lines smaller than the pipe.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Control valves can experience excessive lag (react too late) if the sensor is installed too far away.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">There may be a low air supply at the actuator or air leaks away, which results in less force being available to move the stem.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It is possible for the stem of a control valve to become sticky if the packing is too tight or if there is a leak in the product.<\/span><\/li>\n<\/ul>\n<h3><i><span style=\"font-weight: 400;\">Control Action\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">Using an air-operated valve as an example, there are two control actions available:<\/span><\/p>\n<p><span style=\"font-weight: 400;\">&#8220;Air or current to open&#8221;: As the control signal value increases, the flow restriction lowers.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">&#8220;Air or current to close&#8221;: The flow restriction rises as the control signal value increases.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Failure to safety modes can also occur:<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Failure of an air or control signal to close &#8220;- If the compressed air supply to the actuator fails, the valve closes under spring pressure or with backup power.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Failure of an air or control signal to open &#8220;- If the compressed air to the actuator fails, the valve opens by spring pressure or by backup power.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The types of failure operation are required by the plant&#8217;s failure to safety process control specification. In the case of the cooling water, it may fail open, whereas it may fail closed in the event of chemical delivery.<\/span><\/p>\n<h3><i><span style=\"font-weight: 400;\">Control Valve Tuning\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">Tuning the controller determines how the valve reacts to a changing process parameter. Tuning determines the valve response speed and intensity when it detects a need for a correction. The controller contains internal logic which produces a predetermined amount of movement in response to an input.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Tuning the controller determines how the valve reacts to a changing process parameter. Tuning determines the valve response speed and intensity when it detects a need for a correction. The controller contains internal logic which produces a predetermined amount of movement in response to an input. The logic considers some items:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The magnitude of the discrepancy between the controlled parameter&#8217;s value and its setpoint (Proportional);<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Duration of the discrepancy (Integral);<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The speed of changes in the discrepancy (Derivative).<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">After that, it determines how fast and how far the stem should move.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once the trim position has been altered, the controller waits for the next measurement from the sensing element to determine the remaining difference to the set point. Valve stems are moved, and the flow is altered until there is no difference between the setpoint and the actual value of the controlled parameter.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Tuning a control valve can be compared to adjusting the taps under a shower to get the water temperature right. If hot water is turned on first, the control valve will become the cold water tap. Temperature is sensed by your body. The cold water tap is opened if the water gets too hot. The effects of increasing the cold water flow take a while to feel (the time lag). Temperature is adjusted up or down until the desired temperature is achieved from the combined flows. After the valves are at the right temperature, the temperature remains steady.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If something changes, such as someone doing their laundry with cold water, the cold water flow to the shower drops, and the water temperature rises. A change in temperature is again sensed, and adjustments are made. In response, taps are opened further for cold water or closed for hot water. Temperature measurement and a valve position adjustment are carried out until the parameter under control (temperature) stabilizes. The same applies to control valves.<\/span><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Parts_of_Control_Valves\"><\/span><b>Parts of Control Valves\u00a0<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">In general, a control valve consists of three parts, each of which exists in several types and designs:<\/span><\/p>\n<figure id=\"attachment_12310\" aria-describedby=\"caption-attachment-12310\" style=\"width: 888px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"size-full wp-image-12310\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts.png\" alt=\"working principle of control valve\" width=\"888\" height=\"903\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts.png 888w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts-295x300.png 295w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts-768x781.png 768w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts-696x708.png 696w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/control-valve-parts-413x420.png 413w\" sizes=\"(max-width: 888px) 100vw, 888px\" \/><figcaption id=\"caption-attachment-12310\" class=\"wp-caption-text\">Parts of a control valve (Reference: <strong>cncontrolvalve.com<\/strong>)<\/figcaption><\/figure>\n<h3><i><span style=\"font-weight: 400;\">Valve Actuator\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">Valves have actuators that move the modulating elements, such as balls or butterflies.<\/span><\/p>\n<h3><i><span style=\"font-weight: 400;\">Valve Positioner\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">This device ensures that the valve has been opened to the desired degree. Friction and wear problems are thus eliminated. Positioners have the function of delivering pressurized air to the valve actuator to set the valve&#8217;s stem or shaft corresponding to a set point in the control system. A positioner is typically used when throttling is required.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Positioners are designed to take position feedback from the stem or shaft of a valve and deliver the pneumatic pressure to an actuator to open and close the valve. This positioner must be attached to or close to the control valve assembly.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Positioners are categorized according to types of control signals, diagnostic capabilities, and communication protocols, including pneumatic, electric, electro-pneumatic, and digital.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Pneumatic Valve Positioner\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">A pneumatic device sends and receives pneumatic signals. It is intrinsically safe and can close valves with a lot of force.<\/span><\/p>\n<figure id=\"attachment_19601\" aria-describedby=\"caption-attachment-19601\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"size-full wp-image-19601\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/12\/11-Pneumatic-Valve-Positioner-Reference-donjoyvalve.com_.jpg\" alt=\"\" width=\"500\" height=\"400\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/12\/11-Pneumatic-Valve-Positioner-Reference-donjoyvalve.com_.jpg 500w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/12\/11-Pneumatic-Valve-Positioner-Reference-donjoyvalve.com_-300x240.jpg 300w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><figcaption id=\"caption-attachment-19601\" class=\"wp-caption-text\">Pneumatic Valve Positioner (Reference <strong>donjoyvalve.com<\/strong>)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Using a single-acting valve actuator with range springs, a single-action (or a three-way) pneumatic positioner sends air to and exhausts air from only one side of the valve. However, double-acting or four-way pneumatic positioners can move air on both sides of the actuator.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Electric Valve Positioner\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">Electrical signals are sent and received by electric valve positioners. Electric motors can be either single-phase or three-phase run on alternating current (AC) or direct current (DC).<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Electro-pneumatic Valve Positioner\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">Current control signals are converted into pneumatic equivalents by electro-pneumatic valve positioners.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Digital Valve Positioner\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">Digital or smart devices control and record data and position the valve actuator with the help of a microprocessor. This type of positioner is highly accurate, uses less air than analog positioners, and allows for online digital diagnostics.<\/span><\/p>\n<figure id=\"attachment_19600\" aria-describedby=\"caption-attachment-19600\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"size-full wp-image-19600\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/12\/10-Digital-Valve-Positioner-Reference-coulton.com_.png\" alt=\"\" width=\"300\" height=\"182\" title=\"\"><figcaption id=\"caption-attachment-19600\" class=\"wp-caption-text\">Digital Valve Positioner (Reference <strong>coulton.com<\/strong>)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">A digital valve controller performs two additional functions in addition to controlling the valve&#8217;s position: diagnostics and two-way digital communication. As a result, smart positioners provide the following advantages when used on control valves:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Calibration and configuration of the positioner automatically.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A real-time diagnostics system.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Reduced installation and calibration costs for loop commissioning.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Maintaining loop performance with diagnostics.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Reduced process variability through improved process control accuracy.<\/span><\/li>\n<\/ul>\n<h3><i><span style=\"font-weight: 400;\">Valve Body\u00a0<\/span><\/i><\/h3>\n<p><span style=\"font-weight: 400;\">A valve body contains the modulating element, such as a plug, globe, ball, or butterfly. There are two basic types of valves; plug and seat valves, where the plug is closed against the seat, or quarter-turn valves that have a disc, ball, or cone turning against the seat.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">It is the valve trim that is responsible for regulating the flow of water. There is a fixed-in-place seat along with a moveable plug, disc, ball, or cone. Various passage shapes can be created using the trim, which manages the flow in a deliberate manner.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There are three main types of control valve trim:<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Snap Trim (also known as Quick-Opening Trim)\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">Snap Valve Trims open quickly and are used for on\/off operation. Among the common applications are liquid dumps, pressure reliefs, and metering. Zirconia seats are also available for erosive applications.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Nominal Trim (also known as Linear Trim)\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">Typically, nominal valve trim is used to throttle liquids, control liquid level, and prevent water hammering.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400;\">Equal Percentage Trim\u00a0<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400;\">The equal percentage valve trim is used in throttling applications to control the flow or the pressure of gas and vapor.<\/span><\/p>\n<figure id=\"attachment_12312\" aria-describedby=\"caption-attachment-12312\" style=\"width: 659px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" class=\"wp-image-12312 size-full\" src=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/trim-types.png\" alt=\"working principle of control valve\" width=\"659\" height=\"230\" title=\"\" srcset=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/trim-types.png 659w, https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/10\/trim-types-300x105.png 300w\" sizes=\"(max-width: 659px) 100vw, 659px\" \/><figcaption id=\"caption-attachment-12312\" class=\"wp-caption-text\">Three main types of valve trim (Reference: <strong>vakratoond.com<\/strong>)<\/figcaption><\/figure>\n<h3><b>Buy Equipment or Ask for a Service<\/b><\/h3>\n<p>By using Linquip RFQ Service, you can expect\u00a0to receive quotations from various suppliers across multiple industries and regions.<\/p>\n<p style=\"text-align: center;\"><strong><a href=\"http:\/\/linquip.com\/get-quote?utm_source=blog&amp;utm_medium=content&amp;utm_campaign=product_list&amp;utm_term=product_list&amp;utm_content=rfq\" target=\"_blank\" rel=\"noopener\">Click Here to Request a Quotation From Suppliers and Service Providers<\/a><\/strong><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Download_Working_Principle_of_Control_valve_PDF\"><\/span>Download Working Principle of Control valve PDF<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<div class=\"su-button-center\"><a href=\"https:\/\/www.linquip.com\/blog\/wp-content\/uploads\/2021\/12\/linquip.com-Working-Principle-of-Control-Valve-with-Diagram.pdf\" class=\"su-button su-button-style-default su-button-wide\" style=\"color:#FFFFFF;background-color:#2D89EF;border-color:#246ec0;border-radius:12px\" target=\"_blank\" rel=\"noopener noreferrer\"><span style=\"color:#FFFFFF;padding:0px 30px;font-size:22px;line-height:44px;border-color:#6cadf4;border-radius:12px;text-shadow:none\"> Download PDF<\/span><\/a><\/div>\n<p>&nbsp;<\/p>\n<p><em><span style=\"font-size: 10pt;\"><strong>Read More on Linquip<\/strong><\/span><\/em><\/p>\n<ul>\n<li><span style=\"text-decoration: underline;\"><span style=\"font-size: 10pt; 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Working Principle, Types &amp; Applications<\/a><\/strong><\/span><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><span style=\"font-size: 10pt; font-family: verdana, geneva, sans-serif;\"><strong><a href=\"https:\/\/www.linquip.com\/blog\/what-are-coaxial-valves-working-principles-and-types\/\" target=\"_blank\" rel=\"noopener\">What are Coaxial Valves? Working Principles and Type<\/a><\/strong><\/span><\/span><\/li>\n<li><span style=\"text-decoration: underline;\"><span style=\"font-size: 10pt; font-family: verdana, geneva, sans-serif;\"><strong><a href=\"https:\/\/www.linquip.com\/blog\/what-is-isolation-valve\/\" target=\"_blank\" rel=\"noopener\">What is Isolation Valve? Working Principle &amp; Types<\/a><\/strong><\/span><\/span><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The working principle of control valve is opening or closing internal passages in order to regulate the flow of a liquid or gas. Control valves are part of a control loop that controls a process. Control valves adjust internal openings in response to instructions from the controller. The control valve is the last control component &#8230;<\/p>\n","protected":false},"author":11,"featured_media":32757,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"categories":[13],"tags":[334],"class_list":["post-12305","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-valves","tag-device-characteristic"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/12305","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/comments?post=12305"}],"version-history":[{"count":7,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/12305\/revisions"}],"predecessor-version":[{"id":37844,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/posts\/12305\/revisions\/37844"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/media\/32757"}],"wp:attachment":[{"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/media?parent=12305"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/categories?post=12305"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linquip.com\/blog\/wp-json\/wp\/v2\/tags?post=12305"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}