PRESSURE RECOVERY (REFER FIG. A)
As a fluid traverses the path from the valve inlet through the valve orifice and to the valve outlet it experiences those three key pressure levels:
P1     - The Valve inlet pressure (Up stream pressure)

CONTROL VALVE SELECTION - (STEP - 1)
1. Select a valve type: A. Try single seated valve 0.9 CF to determine CV required
B. Flow Direction: Always try flow-to open first, then try flow-to-close for actuator process. Flow direction

A selection criteria is provided that assures a control valve will perform its control function without the attendant problems of erosion, vibration, noise and short life. The criteria involves limits on the fluid kinetic energy exiting through the valve throttling area. Use of this criteria has resolved existing valve problems as demonstrated by retrofitting of

The test classifications listed below are for factory acceptance tests under the conditions shown. Because of the complex interaction of many physical properties, extrapolation of very low leakage rates to other than test conditions can be extremely misleading. Consult the appropriate product bulletin for individual valve body leak classifications.

An automatic control valve consists of a valve body and an actuator. The actuator is controlled by a pneumatic or electric signal from a remote point changing the rate of medium flow passing through the valve. VALVE COMPONENTS Actuator - That part of an automatic control valve which causes the valve stem to move.

This discussion will focus on proper sizing and selection of Control Valves with accessories for incompressible and compressible fluids. Today there is little excuse for poor specification and selection of Control Valve as most valves manufacturers provide computer programmers for selection and sizing.
The days of selecting Control Valves based on pipe line sizes are gone

LIQUID LEVEL SYSTEM  CONTROL VALVE PRESSURE DROP BEST INHERENT CHARACTERISTIC

In order to perform even routine maintenance procedures on a control valve, it is important that the maintenance man have a thorough understanding of the fundamental construction and operation of the valve. Without this knowledge, the equipment could be damaged inadvertently, or could cause injury to the maintenance man and others in the area. Most

Bonnet packing, which provides the pressure seal around the steam of a globe-style valve body, may need to be replaced if leakage develops around the stem, or inspection. Before starting to remove packing nuts, make sure there is no pressure in the valve body. If the packing is of the split ring variety, it can be

Many conventional sliding-stem control valves use threaded-in seat rings. Severe service conditions can cause damage to the seating surface of the seat ring(s) so that the valve does not shut off satisfactorily. In that event, replacement of the seat ring(s) will be necessary. Before trying to remove the seat ring(s), check to see if the ring

A certain amount of leakage should be expected with metal-to-metal seating in any globe-style valve body. If the leakage becomes excessive, however, the condition of the seating surfaces of  the valve plug and seat ring can be improved by grinding. Large nicks should be machined out rather  than ground out. Many grinding compounds are available

A lubricator or lubricator/isolating valve is required for semi-metallic packing and is recommended for graphite asbestos and TFE-impregnated asbestos packing. The lubricator or lubricator/isolating valve combination should be installed on the side of the valve bonnet, replacing the pipe plug used with packing types not requiring lubrication. Use Dow Corning X-2 lubricant or equivalent for

High Flow Plug and Cage Trim
The Plug and Cage trim design gives the maximum flow capacity for a cage trim choke valve.  This trim type is proven for effectiveness in high flow liquid and dual phase flow.
In the closed position, the plug makes contact with a prepared shoulder in the cage to facilitate positive shut

This low-tech valve may not have changed much in the last 100 years, but the gate valve plays a major role in virtually every refinery, chemical plant and industrial facility in the world.
The most popular style of valve in the world of flow control is the gate valve. They are the on/off switches of the

The word “trim” is often overheard when valve professionals are talking about industrial gate valves. Trim has nothing to do with how slim and fit a valve is, rather it refers to the internal components of a valve that are exposed to great stress or subject to a harsh combination of erosion and corrosion. In

Gate valves can have one of two different disc designs: parallel or tapered type. Both operate on the principle of a closure element (disc or gate) sliding into a slot in the pipeline and closing off the fluid path. The tapered disc of the “wedge gate” valve is machined to match a pair of body

Gate valves are normally available in five different body/bonnet joint designs. They are: screwed, union, bolted-bonnet, welded-bonnet & pressure-seal.
* The screwed joint is the simplest design. However it is only used for inexpensive bronze valves that rarely if ever require disassembled.
* The union joint is also primarily used on bronze valves, but the union design

Three different bonnet/stem designs are predominant in gate valve construction. They are: inside screw, rising stem (ISRS), non-rising stem (NRS), and outside screw and yoke (OS&Y).
* The ISRS bonnet/stem design is the most popular design in use today on bronze valves. Due to the fact that it exposes the stem threads to the process fluid

Gate valves are manufactured in virtually every metal from Aluminum to Zirconium. They are also manufactured in a variety of engineering plastics. The most common materials however, are steel, iron and bronze. Bronze offers the greatest machinability and the lowest manufacturing cost. The features that make bronze easy to machine, its lower strength and softness, also

The most common method of opening and closing (actuating) a valve is through a handwheel attached to the yoke or bonnet. This works fine on moderate size valves operating at reasonable pressures, but some severe operating situations call for more muscle. For example, an 18”, class 1500, main steam isolating valve in a power plant

Industrial gate valves are often used in harsh environments and sometimes these valves need to be repaired. The decision to repair or replace a valve usually is a result of comparing the replacement cost to the repair cost. When the repair cost exceeds 50-65% of the cost of a new valve, the decision is usually

The piping industry has long recognized the need to control the kinetic energy levels in the transport of fluids through a pipe. The industry has created design criteria that limits the fluid velocity in the pipe to acceptable limits. For example, a normal criteria for liquids in pipes is to limit the fluid velocity to

All Forced Air Systems:  Conventional filters on forced-air systems should be checked monthly and cleaned or replaced as needed. Electronic filters should be checked monthly and cleaned as needed. Care should be taken to ensure the interior components are installed in the correct orientation after cleaning. Noisy blower sections should be brought to the attention

Surfacing for Wear Resistance. For the successful hard surfacing or overlaying operation a welding procedure should be established. The procedure should be related to the particular part being surfaced and the composition or analysis of the part. It should specify the welding process to be used, the method of application, the prewelding operations such as cleaning,

Valve  Bonnet The cover for the opening in the valve body is the bonnet.   In some designs, the body itself is split  into  two  sections  that  bolt  together.   Like  valve  bodies,  bonnets  vary  in  design.   Some bonnets  function simply  as  valve covers,  while others  support  valve internals  and  accessories such as the stem, disk, and

Questions to ask before proceeding
•    Has the system ever worked before? If yes, has anything happened to it since then that could cause the problem?
•    Has this system proven itself to be prone to certain types of failure?
•    How urgent is the need for repair?
•    What are the safety concerns, before I start troubleshooting?
•    What

Pneumatic actuators are commonly used to actuate control valves and are available in two main forms; piston actuators and diaphragm actuators. Piston actuators are generally used where the stroke of a diaphragm actuator would be too short or the thrust is too small. The compressed air is

The direct acting actuator is designed with the spring below the diaphragm, having air supplied to the space above the diaphragm. The result, with increasing air pressure, is spindle movement in the opposite direction to the reverse acting actuator. The effect of this movement on the valve opening depends on the design and type of valve

The thrust available to close the valve has to provide three functions:
1. To overcome the fluid differential pressure at the closed position.
2. To overcome friction in the valve and actuator, primarily at the valve and actuator stem seals.
3. To provide a sealing load between the valve plug and valve seat to ensure the required degree

For many applications, the 0.2 to 1 bar pressure in the diaphragm chamber may not be enough to cope with friction and high differential pressures. A higher control pressure and stronger springs could be used, but the practical solution is to use a positioner. This is an additional item (see Figure 6.6.11), which is usually fitted

1. A positioner ensures that there is a linear relationship between the signal input pressure from the control system and the position of the control valve. This means that for a given input signal, the valve will always attempt to maintain the same position regardless of changes in valve differential pressure, stem friction, diaphragm hysteresis

Sometimes referred to as a SMART positioner, the digital positioner monitors valve position, and converts this information into a digital form. With this information, an integrated microprocessor offers advanced user features such as: High valve position accuracy. Adaptability to changes in control valve condition. Many digital positioners use much less air than analogue types. An auto stroking routine for

In order to position the control valve in response to the system requirements a modulating actuator can be used. These units may have higher rated motors (typically 1 200 starts/hour) and may have built-in electronics. A positioning circuit may be included in the modulating actuator, which accepts an analogue control signal (typically 0-10 V or 4-20

The market for intelligent process control valves is one which has grown rapidly in recent years, with these products offering huge advantages over manual valves. This is not to say there aren’t drawbacks, however. Many of these intelligent valves offer levels of sophistication that many users simply don’t need, and offer options such as fieldbus

Over the many years that I have been writing these articles in the Case Histories series, the one theme that re-occurs very frequently is problems encountered with valves. In recent years I have been told on quite a few occasions by people that their valve problems are over as they have now made the huge

Allocation measurement refers to continuous measurement by which a quantity of hydrocarbon, metered to Custody Transfer standard, is attributed to different sources.
For further information issue 7 of the UK’s DTi guidelines is available on its web link: http://www.og.dti.gov.uk/upstream/measurement/MeasGuidelines_V7.pdf, and is recommended for additional reading.
Space and Weight Early offshore platforms were converted drilling rigs, where space and

A fill valve assembly for a toilet tank or the like includes a riser and a head portion that can be vertically adjusted without removal or disassembly of the valve in order to select a precise tank liquid level. Telescoping conduits in the riser are secured in adjusted position by a bayonet latch system including

High CV values = generally smaller valves = more cost-effective in terms of cost vs. fluid capacity
Inherent unobstructed linear flow, as compared to more turbulent flow characteristic of other valve designs
Self-cleaning, flexing action of the elastomer tube loosens deposits, minimizing problems associated with stiction, overshoot, and other control valve irregularities
Zero-leakage shut-off

Conventional Pinch
Excessive stretching of the rubber sleeve or diaphragm causes more highly accelerated wear under abrasive, erosive, or high temperature and pressure conditions. Conventional pinch valves are not manufactured to standard ASME/ANSI or DIN face-to-face dimensions. Ball, Plug, Gate, Butterfly, and Globe Abrasive wear, scaling, or corrosion of rotating metal, lined surfaces, seats and seals, cause valves

Four-stroke engines, of either spark ignition or compression ignition varieties, use poppet valves to allow air (or an air/fuel mixture) into the cylinder and exhaust gases out. Very early engines used alternative valve types such as slide valves, but these proved less satisfactory, especially for high-speed engines. The poppet valve is pushed into the cylinder by

A ball valve (like the butterfly valve, one of a family of valves called quarter turn valves) is a valve that opens by turning a handle attached to a ball inside the valve. The ball has a hole, or port, through the middle so that when the port is in line with both ends of

A blast valve is used to protect a shelter, such as a fallout shelter or bunker, from the effects of sudden outside air pressure changes. A nuclear weapon creates a shock wave, which may produce sudden pressure changes of more than an atmosphere (about 14 pounds per square inch) even several miles or kilometers from

A butterfly valve is a type of flow control device, used to regulate a fluid flowing through a section of pipe. The valve is similar in operation to a ball valve. A flat circular plate is positioned in the center of the pipe. The plate has a rod through it connected to a handle on

Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, a diaphragm, and a “saddle” or seat upon which the diaphragm closes the valve. The valve body is commonly constructed from high grades of stainless steel, e.g. AISI 316L, inert polymers e.g. PVDF or higher alloys e.g. Ti, Hastelloy. Common

A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It consists of two check valves assembled in series usually with a ball valve or gate valve installed at each end for isolation and testing. Often, test cocks (very small ball valves) are in

A flow control valve regulates the flow or pressure of a fluid. Control valves normally respond to signals generated by independent devices such as flow meters or temperature gauges. Control valves are normally fitted with actuators and positioners. Pneumatically-actuated globe valves are widely used for control purposes in many industries, although quarter-turn types such as

A Gate Valve, or Sluice Valve, as it is sometimes known, is a valve that opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats are planar. The gate faces can form a wedge

A choke valve is valve that lifts a solid cylinder (called a “plug” or “stem”) up and down which is placed around or inside another cylinder which has holes or slots. The design of a choke valve means fluids flowing through the cage are coming from all sides and that the streams of flow (through

Globe valves are named for their spherical body shape. The two halves of the valve body are separated by an internal baffle which has an opening forming a seat onto which a movable disc can be screwed in to close (or shut) the valve. In globe valves, the disc is connected to a stem which

A needle valve is a type of valve having a small orifice and a threaded, needle-like plunger. It allows precise regulation of flow, although it is generally used for, and is capable of, only relatively small flow rates. A needle valve has a relatively small orifice with a long, tapered, conical seat. A needle-shaped plunger, on ...

A Pilot valve is a dead man’s switch which requires a human operator to hold it in the mid-position and take some action if the operator takes off pressure or applies full pressure. Often (especially in heavy rail applications) this type of fail-safe braking is provided with one foot and one hand control to reduce

A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the

The sleeve valve is a type of valve mechanism for internal combustion piston engines which have traditionally relied on the more common poppet valve.
A sleeve valve consists of one or more machined sleeves that fit within a piston engine’s cylinders and are designed so as to move so that their openings align with the cylinder’s

Reed valves consist of thin flexible metal or fiberglass strips fixed on one end that open and close upon changing pressures across opposite sides of the valve much like heart valves do. They are intended to restrict flow to a single direction. Reed valves are commonly used in two-stroke engines to control the fuel-air mixture that

A rotary valve is a type of valve in which the rotation of a passage or passages in a transverse plug regulates the flow of liquid or gas through the attached pipes. The common stopcock is the simplest form of rotary valve. Rotary valves have been applied in numerous applications, including:

A piston valve is a device used to control the motion of a fluid along a tube or pipe by means of the linear motion of a piston within a chamber or cylinder.
Examples of piston valves are: The valves used in the valve gear of many stationary steam engines and most steam locomotives.

A saddle valve is a valve used to supply liquid where a low volume, low pressure stream is required. The name is derived from the fact that it is mounted in such a way that it “saddles” the line, mounting it from both sides. They are typically used for suppling cold water, via a 3/8 in.

A safety valve is a valve mechanism for the automatic release of a gas from a boiler, pressure vessel, or other system when the pressure or temperature exceeds preset limits. They are often called by more specific names such as pressure relief valves, T&P valves, or temperature and pressure relief valves.afety valves were first used

The relief valve is a type of valve used to control or limit the pressure in a system which can build up by a process upset, intrument or equipment failure or fire, by allowing the pressurised fluid to flow from an auxiliary passage out of the pressure vessel. The relief valve is designed or set

The Schrader Valve is a valve stem invented by August Schrader and is used on virtually all automobile tires and lower pressure bicycle tires. It is a poppet valve assisted by a spring. Schrader valves are also used on the fuel rail of some direct fuel injection engines and on some automotive air conditioning systems,

A solenoid valve is an electromechanical valve for use with liquid or gas controlled by running or stopping an electrical current through a solenoid, which is a coil of wire, thus changing the state of the valve. The operation of a solenoid valve is similar to that of a light switch, but typically controls the

Plumbing, from the Latin for lead (plumbum), is the skilled trade of working with pipes, tubing and plumbing fixtures for potable water systems and the drainage of waste. Plumbing originated during the ancient civilizations such as Roman, Persian, Indian, and Chinese civilizations as they developed public baths and needed to provide potable water, and drainage

Variable valve timing, or VVT, is a generic term for an automobile piston engine technology. VVT allows the lift or duration or timing (some or all) of the intake or exhaust valves (or both) to be changed while the engine is in operation. Two stroke engines use a Power valve system to get similar results

Zone valves as used in home hydronic systems are usually electrically powered. In large commercial installations, vacuum or compressed air may be used instead. In either case, the motor is usually connected to the water valve via a mechanical coupling. For electrical zone valves, the motor is often a small shaded-pole synchronous motor combined with a

In my view, the game industry never gets dull. There’s always something coming down the road that fans are going to appreciate. The new year will be no different in that respect. I’m expecting the PC games industry to bounce back big time in 2007. First we get Windows Vista with its built-in game organizer and

One Touch Operation Reduces Oil Changing Time and Expenses Eliminates Stripped Thread No More Contact with Hot Oil No Messy Hands or Cloths Easy Installation Introducing the best way to change oil, the Engine Oil

Pressure Tap For GasFor non-condensing gasses, tapping point should be made to the side or upper quadrant of the process line and fitted with a suitable process isolation valve, The pressure transducer (transmitter) should be positioned above the tapping point with its process connection downwards to allow any condensate

Valve positioners compare a control signal to a valve actuator’s position and move the actuator accordingly. They are used with both linear valves and rotary valves. When a control signal differs from the valve actuator’s position, the valve positioner sends the necessary power to move the actuator until the correct position is reached. There are

Electrohydraulic valve actuators and hydraulic valve actuators convert fluid pressure into motion in response to a signal. They use an outside power source and receive signals that are measured in amperes, volts, or pressure. Some electrohydraulic valve actuators and hydraulic valve actuators move rotary motion valves such as ball, plug, and butterfly valves through a

Pneumatic valve actuators adjust valve position by converting air pressure into linear or rotary motion. Linear motion devices open and close gate, globe, diaphragm, pinch and angle-style valves with a sliding stem that controls the position of the closure element. Rotary motion devices move ball, plug and butterfly valves a quarter-turn (90°) or more from

Electric actuators mount on valves which, in response to a signal, automatically move to a desired position using an outside power source. Single-phase or three-phase AC or DC motors drive a combination of gears to generate the desired torque level. There are two basic types of electric actuators: rotary and linear. Each type of actuator

Industrial valves are classified in many different ways. They can be distinguished by material of construction, media handled, and/or application. Most industrial valves are made of metal or plastic materials. Metal valves are made of aluminum, brass, bronze, copper, cast iron, ductile iron, steel, or stainless steel. Plastic valves are made of acetal polymers, polyvinyl

Steam valves are used to control the flow and pressure level of steam and heated water vapor. They are usually made of aluminum, brass, bronze, cast iron, ductile iron, copper, steel, or stainless steel. There are several basic types of products. Angle valves position the inlet and outlet at 90° to provide maximum flow. Ball

Globe valves are linear motion valves with rounded bodies, from which their name is derived.  They are widely used in industry to regulate fluid flow in both on/off and throttling service.  Globe valves consist of the following moving parts – the disk, the valve stem, and the handwheel. The stem connects the handwheel and the

Positive displacement valves are precision dispensing devices designed to provide precise fluid dispensation depending on applications. They function by opening quickly, releasing product, and closing again.  This process may take place numerous times per second.  Positive displacement valves use physical moving force to drive material out of the valve. They are typically used to dispense

Single component diaphragm valves are designed to provide a precise fluid supply depending on the application. The dispensed output can be a bead, dot or fill. Material pressure upon the valve forces the diaphragm to allow material through the fluid body and out the dispensing tip. Applying air pressure to the top of the diaphragm

Hydraulic valves contain and transfer the flow and pressure of hydraulic fluid in hydraulic power systems. They range from simple shutoff valves to precision control valves. Common types of hydraulic valves include angle, ball, block and bleed, check, control, cartridge, directional, drain, needle, poppet, pressure relief, safety, shut off, solenoid, spool, and stack mounted valves.

Gas valves are used to handle and control the flow of gaseous media such as liquefied petroleum and natural gas. They are made of metal or plastic and vary in terms of valve size, pressure rating, number of ports, and flow. Connection types consist of bolt flanges, clamp flanges, union connections, tube fittings, butt welds,

Air valves allow metered flow of fluid in one or both directions. Many of them allow for free flow in one direction and reduced or metered flow in the reverse direction. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices.  Air valves can be

Control valves or proportional valves are power-operated devices used to modify fluid flow or pressure rate in a process system. Search by Specification | Learn more about Control Valves
Air Valves - (427 companies) Air valves allow metered fluid flow in one or both directions. They are used in pneumatic circuits to regulate

Control valves or proportional valves are power-operated devices used to modify fluid flow or pressure rate in a process system. These valves are used throughout industry in many applications.  Control valves types include globe, diaphragm, pinch, knife or gate, needle, butterfly, ball, and plug.  Globe valves are linear motion valves with rounded bodies, from which

Packing is a sealing system which normally consists of a deformable material such as TFE, graphite, asbestos, Kalrez, etc. Usually the material is in the form of solid or split rings contained in a packing box. Packing material is compressed to provide an effective pressure seal between the fluid in the valve body and the

1. If you are dealing with a corrosive fluid, choose the valve body and trim material to match the pump casing and impeller.
2. Velocity is the key to handling abrasive materials. Normal city water velocity is about 7 to 10 F.P.S. (clean liquid). If you have a fluid that is abrasive, keep the velocity as

Rule of Thumb:
There is no such thing as “Bubble Tight.”
Control valves are designed to throttle. However, this is not a perfect world, and control valves are also usually expected to provide some type of shut-off capability. A control valve’s ability to shut off has to do with many factors. The type of valves for instance.

Trim design will affect how the valve capacity changes as the valve moves through its complete travel. Because of the variation in trim design, many valves are not linear in nature. THE RELATIONSHIP BETWEEN VALVE CAPACITY AND VALVE TRAVEL IS KNOWN AS THE FLOW CHARACTERISTIC OF THE VALVE. Valve trims are specially designed, or characterized,

A valve Positioner is a device used to increase or decrease the air pressure operating the actuator until the valve stem reaches the position called for by the instrument controller.
Positioners are generally mounted on the side or top of the actuator. They are connected mechanically to the valve stem so that stem position can be

Control Valves Do What They Are Told!
Being the Final Control Element in a system is not an easy job. To start with, you are blamed for any and all problems that crop up in the process. You are subjected to corrosion, high velocity, cavitation, flashing liquids, cryogenic temperatures, high temperatures, abrasion, and thermal shock.

INTRODUCTION.
1. Recent inspection programs for metallic pressure containment vessels and tanks have revealed cracking and damage in a considerable number of the vessels inspected. Safety and hazard evaluations of pressure vessels, as also presented in OSHA Instruction PUB 8-1.5, need to consider the consequences of a leakage or a rupture failure of a vessel.

This is the beginning of testing a cylinder for structural integrity. The red tank is a 90 cubic-foot, aluminum scuba cylinder .  It has a working pressure of 3300 psi, the test pressure is 5500 psi.
After insuring the tank is empty, we remove the tank valve.  The tank is then given a thorough visual inspection

Disadvantages of this Technique High energy consumption applications are not applicable to this technique because the energy is limited at the source (or barrier). This technique is limited to low-energy applications such as DC circuits, electro-pneumatic converters, etc. Type n Technique: This technique allows for the incorporation of circuits in electrical instruments that are not capable of igniting specific flammable gases or vapor-in-air mixtures under normal operating conditions.

Flameproof Technique: This technique is implemented by enclosing all electrical circuits in housing and conduits strong enough to contain any explosion or fires that may take place inside the apparatus.
Advantages of this Technique Users are familiar with this technique and understand its principles and applications. Sturdy housing designs provide protection to the internal components of the apparatus and allow their application in hazardous environments.

Remove the valve cover to access the drive assembly.
Disconnect the power source plug (black wire) from the PC board prior to disconnecting the motor plug from the PC board. The
motor plug connects to the two-pin jack on the left-hand side of the PC board. The power source plug connects to the four-pin jack.

Bypass Valve
The bypass valve is typically used to isolate the control valve from the plumbing system�s water pressure in order to perform control valve repairs or maintenance. The WS1 bypass valve is particularly unique in the water treatment industry due to its versatility and state of the art design features. The 1� full flow bypass valve incorporates Drive Gear Cover The drive bracket holds the PC board, the motor, the drive gears and the drive gear cover in place. The PC board receives and retains information, displays the information, determines when to regenerate and initiates regeneration.

Control Valve Function and Cycles of Operation This glass filled Noryl1 fully automatic control valve is designed as the primary control center to direct and regulate all cycles of a water softener or filter. The time clock control valve can be set to perform downflow regeneration or simply backwash. The time clock control valve has two

General Information on Elastomer Materials BUNA “N” Buna “N” is commonly referred to as a nitrile rubber, and is ASCO’s standard synthetic elastomer for accomplishing resilient-type seating or sealing. It has excellent compatibility for most air, water and light oil applications. It has a useful temperature range of 0F. ( - 18°C.) to 180°E (82°C.).

Let’s face it. Control valves never make anyone’s top 10 list of favorite topics. Yet while they may be considered boring, control valves can impact your bottom line in ways you may not have considered.
A brief example illustrates why. Figure 1 documents control loop performance testing within a power plant and reveals how control valves can affect a process. The loop

On the surface, this whole subject can appear to be pretty simple. However, ensuring that control valves will shut off properly when installed and throughout their service life requires an understanding
of the physical principles behind shutoff. First, how much leakage can be permitted for a given control valve application? ANSI specifies six different leakage classes. A Class I valve

So far, we’ve discussed how you need to make sure you consider more than just static performance when selecting control valves. But even if you do your homework and have selected the best
valve from an overall financial performance standpoint, how can you be sure the valve will sustain that performance over the life of the plant? This is where

Real Life Experience As you can see, the game has changed. Focusing on dynamic performance of a process control system by optimizing control valve performance can have a very positive impact on your O&M budget and your throughput. Utilizing modern digital equipment to monitor your valves and establishing a state-of-the-art maintenance program can further boost your bottom line. We’ll complete

1. Valve...

2. Control Valve

3. Theory

4. Valve Characteristic

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