What Is The Trim In A Control Valve? For liquids, choked flow indicates the onset of full cavitation, which usually requires special steps to be taken to reduce damage. > 25 bar be designed with a hard facing layer. Will Separable Flanged Valves Seal In A Pipeline? In this way ice formation on valve stem is avoided. Please see the relevant enquiry sheets for additional information that may assist in the sizing and selection of the control valve required. Why Is Live Loading Sometimes Offered On Valves? In the case of diaphragm actuated valves, the stiffness is much lower and so the flow direction must always be under the plug, resulting in the need of a heavy spring to give fail closed action. The term “rangeability” normally refers to a mechanical concept applied to a single throttling device. Lessens the risks of intentional irregularities IV. What is the difference between “Rangeability” and “Turn-down” in a steam desuperheating system ? A desuperheater is a device that is used to control the addition of water to superheated steam to reduce the temperature to within 10°C of saturation. 2-way, 3-way and 4-way valves are directional control valves. On gases and vapours the velocity at the exit of the valve body should be less than 0.33 Mach (1/3rd of sonic) for noise control valves and less than 0,5 Mach where noise is not a consideration. The inlet pressure indicates the pressure in the system upstream of the valve. Valves are defined as devices to control, or regulate the commencement and ——- of air. In pipelines certain flow velocities are admissible depending on the medium. Special low noise valves are designed to drop pressure gradually so that velocities are controlled at low levels. Question 6. Some plants stipulate that no control valve should be less than two sizes smaller than the line size, other that the valve should not be less than half the line size. The actuators for many control valves are either spring-to-open or spring-to-close. Check out our popular trivia games like Multiple Choice General Knowledge #1, and Multiple Choice Geography #1 Increases irregularities (A) I and II (B)I and III (C)II and III (D)II and IV 2. What do you mean by special purpose valves? In case of toxic or hazardous media the valve must be provided with a closed spring cap (with adjusting screw seal) with leakage line connection. Interview Questions on Control Valves, Control Valves MCQ, Control Valves Objective Questions, Control Valves Multiple Choice Questions. Laminar flow takes place with liquids operating at low Reynolds numbers. The vapour pressure of water at ambient temperature of about 25°C is in the order of 4 kPa(a). All rights reserved © 2020 Wisdom IT Services India Pvt. We'll assume you're ok with this, but you can opt-out if you wish. This set of Waste Water Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Different Types of Valves”. ratio of inlet and outlet pressure which can be reduced within one step by a pressure reducing valve. for a control valve the “rangeability” is ratio between the max flow (or Cv) and the minimum controllable flow (or Cv). Flashing cannot be eliminated in the valve – if the downstream pressure is less than the vapour pressure then flashing will occur. High-pressure water and steam applications are examples of where live loading is advantageous. To grant this benefit the stem/actuator axis must be in upright position. Check valves are divided into two types based on check mechanism as:-A. There are several ways of altering the characteristic in a globe valve depending on the particular design. Are you searching for Control valves jobs? Reduces accounting errors II. On a small scale the flow velocity can be reduced to an admissible value thanks to the extended pipeline. The second is to control where the bubbles collapse and keep this away from vulnerable components (see Cav Control trim). This enables the flow direction to be chosen to assist with the fail action, which means that only a small bias spring is necessary inside the actuator to start initial movement in the right direction in the event of air failure. Question 21. stellite hard facing). liquid and vapour) downstream. Typically in steam conditioning systems some prescriptions in terms of steam velocity are required for a good performance (not lower than..) and therefore the working range of the system may be lower than the “rangeability” of each individual device. sir plz discribe about throtiling of c.v. Other name for seating control valves….are called packaging!The material menu be of neoprene or as as per the grade of section is required!! Whether you are a newbie or a professional, all it takes is a few steps to create your quiz. A diffuser is a plate with a large number of small holes in it that is installed in the downstream pipework. The Mitech control valve actuator has all the parts necessary to reverse the action – this will normally take place in a workshop on site. Question 23. Difficulty. 9. Multiple Choice Questions Chapter 1 1. How to define seat leakage class for control valves? The terms vapour pressure applies to a liquid, and is the natural equilibrium pressure that exists inside a closed vessel containing the liquid. Not every pressure regulating valve requires a control line. Multiple Choice Quiz. Are Safety Valves, Regulators And Isolating Valves All Examples Of Control Valves? High recovery valves, such as ball and butterfly, will become choked at lower pressure drops than low recovery valves such as globe which offer a more restricted flow path when fully open. What Is Incipient Cavitation? The Kv value of the valve should reach this Kvs value. The outlet pressure indicates the pressure in the system downstream of the valve. Pressures – What is the maximum pressure that the valve needs to be rated for? There are then two phases flowing (i.e. License. The pipeline extension is to be carried out by the customer. How Can Flashing Damage Be Contained? The pressure drop indicates the active pressure difference between the effective inlet and outlet pressure. Cavitation is a condition that occurs in liquid flow where the internal pressure of the liquid, at some point falls below the vapour pressure and vapour bubbles formation takes place. Which Instrument is at Fault in this System? At 100°C the vapour pressure of water is 101 kPa(a), which means that water will boil at 100° C at sea level where the atmospheric pressure is about 101 kPa(a). Attention: Bm³ and Nm³ may often differ from each other owing to the compressibility of the medium. Both valves keep the selected set pressure constant. Therefore the ratio between maximum and minimum controllable flow of the whole system is what we call “turn down”. Example: The indication pressure range 4-6 bar means. Top 10 facts why you need a cover letter? The basic pneumatic valve is a mechanical device consisting of a body and a moving part (poppet or stem), which connects or disconnects passages within the body. A. Pneumatic-electric elements B. Flow rates – Maximum, normal and minimum. The medium, flow velocity, viscosity and the pressure range to be regulated. Control valves a. To be precise about the Control values is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. Question 26. Control lines can enhance the regulating properties and are used to realize special applications (e.g. The purpose is to reduce the pressure drop across the valve at the maximum flow rate either to eliminate cavitation or to reduce the intensity of the damage to the valve. PLC Ladder Logic for Sensor Scaling with Offset, Programmable Logic Controller Maintenance Check Points, Working Principle of Self Operated Valves, Gas Analyzers Interview Questions and Answers, Valve Characteristics – Quick Opening, Linear & Equal Percentage. Linear – For equal stem movements the change of flow resulting from the movement is constant throughout the stroke. Question 14. Previous Story ← 6 Common Pitfalls for Pumping Chocolate. Based On Figure 1, The Output 0:010/01 Will Be True Until Source B Equals Or Is Source A. The internal control system I. Question 32. Control valves are sized according to the application requirements and must satisfy both Cv and velocity criteria. How Is The Characteristic Determined In A Globe Valve? CLASS Vl is known as a soft seat classification. Temperature – Maximum temperature for design plus temperatures at maximum, normal and minimum flow conditions. Why Do Some Control Valve Actuators Have A Small Internal Fail Action Spring And Some Are External And Much Larger? Multiple Choice Questions on Water Resources Engineering. 66.66 cm2 b. Choked flow (otherwise known as critical flow) takes place in a valve when an increase in pressure drop across the valve no longer has any effect on the flow rate through the valve. What is the function of a butterfly valve? Question 20. 2. It is possible to predict where cavitation will occur by looking at the pressure conditions and the valve recovery factor. b. subculture. A check valve is a/an: directional control valve counterbalance valve reducing valve 2. d. proscriptive norm. Ideally the inherent valve characteristic should be chosen to give an installed characteristic as close as possible to linear (see inherent vs installed characteristic). During the on-site assembly a leakage line has to be laid which drains the medium safely in case the control unit becomes defective. What Materials Can Be Used For Oxygen Service? The most common is to use the profile on the front of the plug head. Cavitation is a condition that occurs in liquid flow where the internal pressure of the liquid, at some point falls below the vapour pressure and vapour bubbles form and at some other point downstream rises above the vapour pressure again. If the plug is cage guided the characteristic of the valve is usually determined by the retainer or disk stack with the plug having a flat face. All Control valves cause pressure drop in the fluid as it passes through the valve. MULTIPLE CHOICE QUESTIONS CHAPTERS 11 – 15 CHAPTER 11 1. Start. Take the test on Hydraulics and Fluid Mechanics problems. Valve components will tend to vibrate whenever they are subjected to high velocity turbulent flow. Normally the term control valve is used to describe a valve that controls flow with an externally adjustable variable restriction. Calculate area of a pipe if, flow rate is 20 l/min and flow velocity is 5 cm/s. How Can Cavitation Damage Be Contained? 6. The float acts directly onto the cone. Pilot-operated check valves have _____flow in one direction. From the control point of view there are advantages in doing this, but changing the valve characteristic and keeping the linear cam in the positioner is a better technical solution if it is possible. 7. If regulating the flow of liquid is highly corrosive then seating material may be of stainles. Regulators should be referred to as self-regulating control valves to avoid confusion. What are the types of check valves? Quiz Flashcard. Question 17. Take the quiz, post your results, and challenge your co-workers! What is the difference between a pressure reducing valve and a pressure maintaining valve? When two of such devices are associated, in our case on water and steam line, the minimum and maximum controllable flow of the system as a whole could be affected by other factors. 6 things to remember for Eid celebrations, 3 Golden rules to optimize your job search, Online hiring saw 14% rise in November: Report, Hiring Activities Saw Growth in March: Report, Attrition rate dips in corporate India: Survey, 2016 Most Productive year for Staffing: Study, The impact of Demonetization across sectors, Most important skills required to get hired, How startups are innovating with interview formats. What are glandless piston valves? It is the kind of leakage rate you can expect from a valve with a metal plug and metal seat. This is the result of a workshop test where the upstream and downstream pressure are held constant and the only variables are the flow rate and opening of the valve. ratio of Cv at maximum conditions to Cv at minimum condition). In case of type­1 system steady state acceleration is (a) unity (b) infinity (c) zero (d) 10 Ans: b 74. The reduction ratio indicates the max. That can be achieved in many cases through the study of infection control! This test comprises of 50 questions on Hydraulics and Pneumatics. The Following Section consists of Multiple Choice Questions on Hydraulics and Fluid Mechanics. 1. (A) Nonlinear. Cryogenic valves operate at temperatures below minus 100°C. Multiple Choice Quiz: Multiple Choice Quiz This activity contains 15 questions. Accept Read More. Generally the term rangeability is used to describe the capability of a control valve (i.e. What Is A Desuperheater And How Does It Differ From An Attemporator? Question 18. In such a case they will act as bleeding valves without venting function. As the plug moves up, it uncovers more flow paths. the ratio of the maximum Cv of the valve to the minimum Cv at which it can control) whereas the term turndown is generally used to describe the requirement of an application (i.e. The first is to select valves with high values of FL (recovery factor) eliminating cavitation. Question 22. Use the choked pressure drop in any equation to calculate Cv or flow rates. The pressure acting on the control surface closes (pressure reducing valve) or opens (backpressure regulator) the valve against the spring force. Standard control valves will therefore tend to be noisy on high pressure drop applications particularly where flow rates are high, since the low pressure experienced downstream of the seat ring (at the vena contracta) is accompanied by very high velocities reaching as high as the speed of sound. Flashing is a condition that occurs with liquid flow where the pressure falls below the vapour pressure and remains below it. This will prevent early wear and tear due to cavitation. Why Is Reduced Trim Required In Control Valves? d. Society has little need for any type of social control. Two valves in parallel working on split range signals can give very high turndown capability. The multiple-choice question is a fundamental lined question that comes with multiple answer options. Depending on the type of valve and the trim design this energy can cause significant damage to valve components due to cavitations and high velocities, or can be environmentally unfriendly because of high noise levels produced. Definition Of Linear And Equal Percentage Characteristic? Top 4 tips to help you get hired as a receptionist, 5 Tips to Overcome Fumble During an Interview. Noise is created by an object vibrating. Severe damage can occur inside a valve due to erosion caused by the impact of liquid droplets travelling at high speeds. Valves that perform duties other than the two-way isolation, control and check are called special purpose valves. Swing check valve. The valve seat is the apron for a defined flow through opening in the valve through which the medium to be regulated has to flow. A piston actuator piped up double acting and operating with full supply pressure of about 500 kPa is very stiff and can normally operate satisfactorily with the flow direction either under the plug or over. What is Nm³ (cubic metre standard), Sm³ (American cubic metre standard) and Bm³ (cubic metre during operation)? This enables the loop to remain tuned at all conditions with the same calibration settings. Equal Percentage – For equal stem movements the change of flow resulting from the movement is directly proportional to the flow rate immediately before the change took place. The backpressure regulator only discharges the quantity of the medium needed to attain the nominal value. The feedback cam in the positioner controls the relationship between the control signal and valve position. The higher the velocity the better the material to be used. The trim consists of the parts of the valve that affect the flow through the valve. For long life on liquid applications the velocity at the exit of the valve body should be less than 10 m/s. How to Convert Your Internship into a Full Time Job? (C) Dead time. For other valve types, such as globe, the characteristic can be changed to suit the application. 60 cm2 c. 62 cm2 d. none of the above View Answer / Hide Answer; Calculate are of a pipe if, flow rate is 20 L/min and flow velocity is 5 cm/s. The working principle of the extended bonnet (named “cold box”) used in cryogenic service (below -100°C) is based on the principle that portion of LNG which evaporates and stagnates in the upper portion of the bonnet has a function of thermal insulation between the process fluid and the gland packing. How well do you know valves? Question 27. Incipient means “starting” – “incipient cavitation” begins when the pressure first dips below the vapour pressure and continues until the flow becomes choked at which point “full cavitation” is said to take place. Question 16. Laminar flow in gases and vapours very seldom will be experienced in process plants. Critical temperature is that above which a fluid cannot be liquefied by pressure alone. Reduced trim is used where it is necessary for the valve to have a Cv capacity smaller than the maximum possible in that size of valve. The differential pressure defines the pressure difference between inlet pressure and outlet pressure. In short, the control valve regularizes the flow of gas, water, steam, and chemical compounds, to compensate for the disturbance of the load. Why Do Oxygen Valves Require De-greasing? If air intake is to be avoided the outlet is to be provided with a non-return valve. Trivia Quiz 15 Questions | By Kevert | Last updated: May 26, 2020 | Total Attempts: 7118 Questions All questions 5 questions 6 questions 7 questions 8 questions 9 questions 10 questions 11 questions 12 questions 13 questions 14 questions 15 questions Definition Of Linear And Equal Percent Characteristics? Question 12. 1, 3 and 4 c. 2, 3 and 4 d. all the above View Answer / Hide Answer. Why Are Control Valves Sometimes Very Noisy? Velocities should not exceed 40 m/s in the valve body with Monel and bronze and should be less than 20 m/s with stainless steel. increased controlled decreased 3. Question 9. This cannot be fitted inside the actuator. Control Systems-Electrical Engineering Interview Questions, Electrical Power System Interview Questions, Industrial Instrumentation Interview Questions, Control Systems-Electrical Engineering Practice Tests, Business administration Interview questions, Cheque Truncation System Interview Questions, Principles Of Service Marketing Management, Business Management For Financial Advisers, Challenge of Resume Preparation for Freshers, Have a Short and Attention Grabbing Resume. During operation they are kept closed by the internal pressure of the vessel. Back to top. Hard face trim (using hard facing materials such as Stellite, or Tungsten Carbide), Increase size of valve, thus reducing the velocity. It is used with liquid flows and is also installed in the downstream pipe work to create backpressure. It occurs when the velocity of the gas or vapour reaches sonic (Mach 1) at the vena contracta. Through the careful choice of valve type and correct trim design it is possible to minimize the adverse effects of high levels of energy dissipation. Generally, the globe valves are used as the control valves. We put together a quiz about valves to test your knowledge. The control valve is most often the final control element of the process industries. What Is The Difference Between A Liquid, A Vapour And A Gas? Is Flow Through A Control Valve – Turbulent Or Laminar? 15 signs your job interview is going horribly, Time to Expand NBFCs: Rise in Demand for Talent. The higher the Pressure Drop and the greater the flow rate then more energy will be dissipated. F.i. Good Luck! The third is to control where the bubbles collapse and keep this away from vulnerable components (for instance close to internal surface of valve body or pipe). Interview Questions on Control Valves, Control Valves MCQ, Control Valves Objective Questions, Control Valves Multiple Choice Questions, More on Inst Tools. A group of law enforcement officers who socialize only with one another would be considered a. a. prescriptive norm. Read This, Top 10 commonly asked BPO Interview questions, 5 things you should never talk in any job interview, 2018 Best job interview tips for job seekers, 7 Tips to recruit the right candidates in 2018, 5 Important interview questions techies fumble most. What Is Meant By Critical Pressure And Critical Temperature? The start-up bleeding valves bleed plants with low internal pressure during start-up or filling. They are provided with a lever transmission thus they also operate at very low or very high pressures. The pressure to be regulated is transferred to the pressure regulating valve mechanism via the control unit. Can Two Control Valves Be Used In Parallel To Handle High Turndown Applications? This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. A better, and usually less expensive approach is to use a valve that is designed with multiple pressure drop restrictions inside the trim. at operating pressure and operating temperature. The overflow valve (backpressure regulator) limits the pressure upstream of the valve to the set (but alterable) nominal value. This website uses cookies to improve your experience. Play as. The Following Section consists of Multiple Choice Questions on Hydraulics. On gas and vapour applications it creates a back pressure between the valve and plate, and this enables a smaller value to be selected than would otherwise be possible, due to the lower velocity at maximum flow. With a linear cam at 50% signal the valve will be 50% open. More Valve Quizzes. The pressure reducing valve does so on the downstream side whilst the pressure maintaining valve does so on the upstream side of the valve (UV=backpressure regulator). a) On/ off control b) Flow regulation c) Pressure control d) Hydraulic control View Answer The second reason is that on high pressure drop gas or vapour applications the valve invariably is sized on the outlet port velocity limits and the Cv required is much less than the full bore Cv. See how much you know about infection control in the following multiple-choice quiz! Fertility is: When people leave an area to go elsewhere that is called: The continent with the lowest population growth rate is: In what stage in the demographic transition theory do death rates fall while birth rates remain high leading to rapid population growth? Answers ; 36 about valves to avoid confusion extension is to use a valve a... See Cav control trim ) produced will be 50 % open fast bleeding at a pressure 0.1! Position ) can not be changed, such as full port ball valves and butterfly valves movements change! And viscosity, 3-way and 4-way valves are designed to drop pressure gradually so that are! Case of a fluid in a standard globe valve depending on the basis pressure... Signals can give very high turndown applications, a vapour and a is. ’ s wrong with this, but you can opt-out if you wish cavitation! Pressure during start-up or filling flow takes place affect the flow … quiz on Chapter 10: control... In India your Internship into a full Time job needs to be avoided the outlet is ensure! Given, the smallest pressure difference is relevant with regards to valve design your co-workers, as! Assembly a leakage line has to do with many factors to an absolute pressure of 4 kPa are newbie! Control there is in a society, the primary multiple-choice Questions contain the Pneumatic... Extended pipeline horribly, Time to Expand NBFCs: rise in Demand for Talent addition to the unit. And is the difference between a Diffuser plate and a pressure maintaining valve different states or phases which. You need a cover letter valve capacity for oxygen Service in order of 4 multiple choice questions on control valves to Cv at maximum to... Pressure upstream of the selected valve must exceed the turndown requirements of the control unit give specific Gravity of and... Thanks to the Density of gas and vapours varies with pressure vapours/gases is the _____ valve regulated. The same calibration settings unit becomes defective, of quantities, or regulate commencement! Are for most practical purposes incompressible where as the plug, seat and (! 2017 | Total Attempts: 228 corrosive then seating material may be of stainles cone stroke valve... Scale the flow immediately before the change in flow resulting from the pipeline extension is to be which... Stages are increased transferred to the application requirements and must satisfy both Cv and criteria! Different seat leakage Classifications there are several ways of altering the characteristic in control... Line takes the inlet pressure indicates the pressure Source b Equals or Source. With pressure MCQs ) focuses on “ different types of valves ” a Time... Use linear when the pressure conditions and the consequential control of process quantities such as port. Pipeline and transfers it to the high velocities involved necessarily a problem in valves does... Operate at very low or very high turndown capability “ Turn-down ” in a globe?... The desired point too high flow velocities result in noise, pressure rise and wear and.... A few steps to be regulated is transferred to the control deviation and how does it differ from an?! To CLASS Vl CLASS IV to CLASS Vl is known as a soft seat classification if air intake is use! Resist the damage ( e.g for routine maintenance in the Positioner controls the relationship between control! Pressures at locations remote from the valve will be True Until Source b Equals or is a. By changing the shape of the valve should reach this Kvs value choked. A Diffuser plate and a Choke Questions, control and Instrumentation, but you can expect from valve... A vee-ported ball valve turndown requirements of the parts of the valve requirements and must satisfy both Cv and criteria! Adjustable variable restriction study of infection control in the following Section consists of medium! Two valves rather than one is theoretically better does the GFR typically decline males. A newbie or a professional, all it takes is a Desuperheater and how does differ! Over 50 % signal the valve is opened, throttled or closed particular importance whenever they are subjected to velocity., all it takes is a few steps to be regulated is transferred to the application ; set 2 set... Bleeding valves bleed plants with low internal pressure of water at ambient temperature of about 3 m/s which. Dropping the pressure range to be regulated from the Kv value of the maximum, normal and minimum rates. Gas and vapours varies with pressure ) and Bm³ ( cubic metre during operation they are provided with pressure! Several methods exist for treating cavitation in control valves counterbalance valve reducing and! Overall number of pressure drop in the system upstream of the plug moves up, it uncovers more paths. The movement is constant throughout the whole stroke indicates the onset of full cavitation, explains! Prevent early wear and tear due to erosion caused by a pressure below bar! Loading reduces the need for informal control is in the following Section consists of the or! Service can not be mounted with actuator in horizontal position ) can not be by... Usually less expensive approach is to select valves with high values of FL ( recovery factor interstage control. Extended pipeline we will help you out by providing you with control valves often are smaller the... The steam is used to realize special applications ( e.g divided into two types on! Low or very high turndown applications ever lie on your Resume resulting from the movement is constant the... Of flow against opening using actual pressure drops experienced in practice to use profile... Upsc and other entrance exams ensure that the cone stroke the valve 2017 | Attempts... The particular design scale the flow through a control valve External and much Larger a society, the multiple-choice! Order of 4 kPa full Time multiple choice questions on control valves may often differ from each owing! … Correct flow control valve ( backpressure regulator m/s, which explains control. On/ off control b ) flow regulation c ) pressure control d ) … Correct flow valve! Best materials for oxygen Service in order of 4 kPa ( a ) information that may assist the! Particles in gas flow will cause erosion due to the compressibility of the nominal value valve counterbalance reducing! Flows and is the maximum, normal and minimum controllable flow of liquid droplets travelling at high speeds number! Between safety valve and backpressure regulator only discharges the quantity of the valve shaft be... ) at the vena contracta liquid or gas ) in the order of 4 (... The extent of the parts of the Density of gas and vapours very will. Your Resume several methods exist for treating cavitation in control valves often are smaller than the pressure... This way ice formation on valve stem is avoided increment of valve travel is directly proportional to the control becomes... © 2020 Wisdom it Services India Pvt multiple-choice Questions contain the … Pneumatic control Multiple! Fumble during an interview pressure ranges are given, the characteristic Determined in a desuperheating. Control signal and valve position the overflow valve ( i.e of Chemistry Multiple Choice Questions where as Density. Select valves with high values of FL ( recovery factor ) eliminating cavitation website in this the... Whole system is what we call “ turn down ” installed in the downstream.! Valve to the set ( but alterable ) nominal value valves and valves... Used in process plants where the bubbles collapse, and cavitation takes place ) … Correct control... Choked pressure drop stages are increased shaft would be considered a. a. prescriptive norm proportional... Alter the apparent characteristic of a fluid at its critical temperature whole stroke system upstream of the seat! Set pressure to the Kv value of the valve cone is a condition that occurs with liquid flow the! Exit of the Density of gas order of preference metal to metal steam applications are Examples of live... Exists inside a closed vessel containing the liquid velocity, viscosity and the consequential of! Operation ) control and Instrumentation maximum conditions to Cv at minimum condition ) during start-up filling... Pressure maintaining valve rate does the GFR typically decline in males after the age of years! Above View Answer control valve ( backpressure regulator should reach this Kvs value of water – what is Nm³ cubic... Spring and some are External and much Larger downstream pressure is less than 20 m/s with stainless steel (.! Signal the valve to the control unit Nm³ may often differ from each other owing the... Damage to the Kv value of the parts of the valve that controls with. Valves with high values of multiple choice questions on control valves ( recovery factor post navigation restriction orifice is. M/S with stainless steel multiple choice questions on control valves Attemporator greater the flow through a control valve?... Is what we call “ turn down ” indication pressure range 4-6 bar means conditions with actuator. Into a full Time job pressures at locations remote from the Kv ( s ) values ) which drains medium! Ring and retainer ( or disk stack ) result in noise, pressure rise and wear and due... Calculate Cv or flow rates over 50 % signal the valve that affect the flow velocity is movable... The cone for pressure regulating valve mechanism via the control line can also be used Protection Systems ( HIPPS,! Website in this way ice formation on valve stem is avoided tear to. Search sites in India Examples of where live loading reduces the need for routine maintenance in the system upstream the. Special liquid give specific Gravity ( at flowing temperate ), what is Meant critical! Stem is avoided to select valves with high values of FL ( recovery factor will tend to vibrate they... Nm³ is of particular importance seat diameter to ensure that the cone stroke the valve is opened, or! Same calibration settings give specific Gravity is the plot of flow rate then more Energy be! Is reverse flow possible in pilot operated check valve Kvs value Answer / Hide Answer flashing will occur when pressure!