Control Valves and Positioners

Throttling Range

the number of units of the process variable that causes the actuator to move through its entire range

Vena Contracta

the point of lowest pressure and highest velocity downstream from a primary flow element

Valve Flow Characteristics

the relationship between the valve flow (in percent) and the control valve open travel (in percent), with all the other factores that affect flow held constant

Direct Acting

As the process variable increases so does the manipulated variable.

Reverse Acting

As the process variable increases the manipulated variable is decreased.

ON/OFF Control Valve

A valve used to start and stop flow in pipelines that control chemicals and energy sources for automatic sequencing, batching, or safety operations.

Yes

Can this positioner be changed from dirert to reverse action?

It is regulated by the position of a free-floating ball that moves in response to fluid or mechanical pressure.

How does this ball valve work?

Water hammer.

Manually operated ball valves can be closed quickly and thus there is a danger of what?

pneumatic, electronic, electro-pheumatic and digital.

Name the four basic valve positioner types..

Rangeability

Ratio of maximum flow to minimum flow, also called turndown ratio.

positioner

What is this object?

A Ball for a Ball Valve.

What is this?

A two way Ball Valve.

What is this?

Globe control valve with the pneumatic actuator and smart positioner.

What kind of valve and 3 most important parts to it?

Equal Percentage Opening Valve Cage

What kind of valve cage is this?

Linear Opening Valve Cage

What kind of valve cage is this?

Quick Opening Opening Valve Cage

What kind of valve cage is this?

Diaphragm Actuator.

What type of actuator does this valve have?

A Piston Actuator.

What type of actuator is this?

Butterfly valve

What type of valve is shown?

V ball valve

What type of valve is shown?

A Ball valve.

What type of valve is this?

Manual ball valve

What type of valve is this?

Valve Body

a casting or forging with an enclosed port and integral threaded or flanged inlet or outlet openings

Actuator

a device that provides the power and motion to maniputlate the moving parts of a valve or damper used to control fluid flow through a final element.

Flapper

a flap piece of metal installed at right angles to a nozzle tip that is held in position a few thousandths of an inch away from the nozzle tip by a linkage to a measurement device such as the diaphragm of a pressure gauge

Valve Plug

a machined disc or shaped piece that regulates the flow by changing the size fo the valve opening

Bellows

a mechanical pressure sensor consisting of a one-piece, collapsible, seamless metallic unit with deep folds formed from thin-wall tubing with an enclosed spring to provide stability, or with an assembled unit of welded sections

Valve Bonnet

a packing enclosure that is bolted or threaded to the top of the valve body

Way

a path through a valve from an inlet port to an outlet port

Double-Acting Actuator

a piston actuator that has an air connection at each end of the piston and does not contain a spring to allow for know failure position

Valve Stem

a valve component that consists of a metal shaft that transmits the force of the actuator to the valve plug

Butterfly Valve

a valve with a disc that is rotated perpendicular to the valve body

Diaphragm and Spring actuator

an actuator consisting of a large-diameter diaphragm chamber with a diaphragm backed by a plate attached to the actuator stem and opposed by the actuator stem

Pressure Regulator

an adjustable valve that is designed to automatically control the pressure downstream of the regulator

Single-Port Globe Valve

is a globe valve that consists of a single valve plug and seat ring through which the fluid flows

Three-Way Globe Valve

is a globe valve that consists of three pipe connections and is used for mixing, blending, or flow division or diversion applications

Double-Port Globe Valve

is a globe valve that consists of two plugs and seat rings through which the fluid flows

Equal Percentage Valve

is a valve that allows the flow rate to change by an amount equal to the change in the opening percentage

Quick Opening Valve

is a valve that allows the flow to increase quickly with a small initial opening

Linear Opening Valve

is a valve that allows tthe flow to increase at the same rate as the opening

Throttling Control Valve

is an assembly of a valve and an actuator that is able to modulate fluid flow at any position between open and fully closed in response to signals from a seperate controller

Control Valve

is the most common final element that receives a control signal and regulates the amount of material or energy in a process

Cavitation

is the process when process where vapor bubbles in a flowing liquid collapse inside a control valve as the pressure begin to increase

Flashing

is the process where a portion of liquid converts to a vapor as it passes through a control valve because the pressure has fallen below the vapor pressure of the liquid

Fail Closed

is this valve a fail closed or fail open valve?

Fail Open

is this valve a fail closed or fail open valve?

Split Ranged Operation

A control configuration where a single control signal, 4 mA to 20 mA or 3 psig to 15 psig, can be directed to two throttling control valves or dampers equipped with electropneumatic positioners.

Final Element

A device that receives a control signal and regulates the amount of material or energy in a process. The most common final element is a control valve.

Positioner

A device used to ensure positive position of a valve or damper actuator. All Positioners have a feedback link from the valve shaft, providing accurate valve position information. The positioner compares the input signal from the controller to the actual valve position and applies a pneumatic output to the actuator to ensure that the valve moves to the proper position.

purple: disc, pink: seat, green: stem, blue: bonnet, red: lever

Identify the colored parts?

This is Direct-Acting

Is this Diaphragm Actuator reverse-acting or direct-acting?

This is Reverse-Acting

Is this Diaphragm Actuator reverse-acting or direct-acting?

Air

Pneumatic valve postioners communicate with what?

Triple Offset Torque Seated

TOTS Butterfly Valves..What does TOTS stand for?