ROTEX Controls USA: Valve Automation 101

Post on 18-Jul-2015

250 views 4 download

Tags:

Transcript of ROTEX Controls USA: Valve Automation 101

AUTOMATION OVERVIEW

EMCISA TrainingNovember 4 -6 2013

STANDARDS

N - NAMURI - I.S.0. 5210/5211V - VDI/VDE 3845

V

V

I

N

N

BOTTOM MOUNTING PAD

TOP MOUNTING PAD

SOLENOID MOUNTING PAD

N

N

Standards

I.S.O. 9000 Series.

I.S.O. 5210 / 5211 Valve Automation Standards.

N.A.M.U.R. Actuation Standards.

V.D.I. / V.D.E. Accessory Standards.

Pneumatic Actuators are

offered in several different

Designs

Advantages:

Simplistic Design.

Rugged.

Torque curve mirrors the Valve characteristics.

Inexpensive for

torque output.

Advantage:

Low cost.

Long History.

Disadvantage:

Does not comply with International Standards.

Torque curve is opposite of Valve characteristics.

Advantages:

Low Cost

Disadvantages:

Not suited for safe spring return design

Uneven O-Ring wear

Does not comply with International Standards

Advantages:

Sold for control.

Disadvantages:

Large Envelope

Heavy

Unbalanced Mounting

Does not comply with International Standards

Advantages:

Compact Design.

Evenly Balanced.

Light Weight.

Complies with International Standards.

Ease of adapting Accessories.

1

23

4 5

6

7

Typical On/Off Automated Valve Package

Valve Cost = 30% of total package

Automation Cost = 70% of total package

# Item Cost as % of

Total Package

2”

Advantages

Hytork

Typical

Valve Dist.

1 Switch 14% Equal or

Greater

Equal or Lesser

2 Bracket 1% Equal or

Greater

Equal or Lesser

3 Conduit 1% Greater Lesser

4 Solenoid 13% Equal or

Greater

Equal or Lesser

5 Actuator 23% Greater Lesser

6 Main Bracket &

Coupling

9% Equal or Lesser Equal or

Greater

7 Valve 30% Equal or Lesser Equal or

Greater

Item Cost as % of

Total Package

Advantages

Hytork

Typical

Valve Dist.

Labor & Handling 9% Equal Equal

Speed of response N/A Equal or Lesser Equal or

Greater

Automated Valve Package Breakout

Typical 1/4-Turn

Modulating

Control Valve Package

Approx. Cost of 3” “V”- notch 1/4-turn = $3000.00

Typical Conventional

Modulating

Globe Valve Package

Automated Valve Package Breakout

Approx. Cost of 3” Globe= $4000.00

End of travel indicating Limit Switches

Used to indicate the final

position of a valve.

Local indication uses a

visual indicator.

Remote indication uses

electrical switches.

Is used as a controller for additional equipment or as a junction house to I/O.

Types of Solenoid Valves

Three Way (Spring return Actuators)

Normally Closed Construction -exhausts pressure when solenoid is de-

energized, applies pressure when energized.

Normally Open Construction -applies pressure when solenoid is de-energized,

exhausts pressure when energized.

Universal Construction -for normally closed or normally open operation.

Four Way (Double Acting Actuators)

Single Solenoid -valve shifts when solenoid is energized, returns to normal position

when de-energized.

Dual Solenoid -valve shifts when one solenoid is energized, returns when the other

is energized. May be energized momentarily or continuously.

COIL DE-ENERGIZED COIL ENERGIZED

AS THE SPRINGS MOVE THE PISTONS TOWARDS EACH OTHER A

PARTIAL VACUUM IS CREATED IN THE SPRING CHAMBERS.

THE EXHAUSTING AIR FROM BETWEEN THE PISTONS IS FORCED

INTO THE APRING CHAMBERS PREVENTING THE ATMOSPHERIC

AIR ENTERING THE ACTUATOR

PISTONS MOVING TOGETHER UNDER SPRING FORCE

PISTONS PUSHED APART BY THE AIR

PRESSURE FORCING AIR FROM THE

SPRING CHAMBERS TO EXHAUST TO

ATMOSPHERE.

TRAVEL STOPS

96°

90°

76°

OVERTRAVEL

OVERTRAVEL

TRAVEL ADJUSTMENT

ROTATION

PINION

Speed Control

Automated Valve Failure

• Valve Leaks-By.

• Actuator not stroking properly.

• Valve will not change position.

• No Limit Switch Indication.

Valve Leaks

• Is the Solenoid Functional ?• Test the Coil.

• Test the spool valve in the solenoid.

• Is the Actuator Traveling 90º ?• Adjust the travel stops.

– Improperly adjusted travel stops or no travel stops will cause valve seat failure.

Actuator not cycling full Stroke

• Air blow-by at the pinion.

– Caused by actuator to valve misalignment.

– Caused by high cycle fatigue.

• Air bleeding through the solenoid exhaust port.– Piston “O”-Ring failure.

• Build up of valve corrosion.– Slow down in cycle time.

– Eventual stroke travel limitation.

• On spring return (Fail Position)

– Broken or Fatigued Springs.

Actuator does not Stroke

• Insufficient air supplyCheck supply pressure with gauge

• Actuator mounted incorrect on valveRemove actuator from valve, check that both are in the

same position before mounting.

• Control components not workingReplace faulty component.

• Required torque greater than sizing torqueResize actuator

Actuator strokes too slow

• Control components too small Cv

Install larger components

• Insufficient volume to actuator

Increase size of supply lines

• Clogged breathers, filters or exhaust port silencers

Check and clean, or replace

• Incorrect speed control settings

Adjust speed controls

Actuator strokes too fast

• Control components too large Cv

Install speed controls

• Too much torque

Lower the supply pressure

• No speed control components

Install speed controls

Actuator strokes jerky

• Insufficient volume supply

Increase supply

• Insufficient torque

Increase supply pressure

Check actuator sizing

Actuator may need overhaul

• Defective valve

Consult valve manufacturer’s documentation

No Limit Switch Indication

• Enclosure is full of water.

• Corrosion on the contacts.

• Cams have vibrated of setting.

• Broken Wire.