Alfa Laval Marine & Power

Pneumatic Change OverValve

Product No.

PrintedBook No.

748393-82748393-83748393-84748393-85

Jun 19971818015-02 V2

Component Description

Alfa Laval reserve the right to make changes at any time without prior notice.

Any comments regarding possible errors and omissions or suggestions for improvement of this publication would be gratefully appreciated.

Copies of this publication can be ordered from your local Alfa Laval company.

Published by: Alfa Laval Separation ABMarine & Power Oil Treatment DivisionS - 147 80 TumbaSweden

Copyright Alfa Laval Separation AB 1995. Printed in Sweden.

and observe the, operation,

ns can result inl injuries.

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0272

Alear only foreseeable conditions have e given, therefore, for situations the machine and its tools.

ion is found in the Safety chapter

Study instruction manuals warnings before installationservice and maintenance.

Not following the instructioserious accidents with fata

In order to make the information cbeen considered. No warnings ararising from unintended usage of

A summary of the safety informatunder divider 1.

Contents

1 Function Description 1

1.1 Application 1

1.2 Working Principle 1

1.2.1 Activated Valve 2

1.2.2 Deactivated Valve 2

1.2.3 Manual Change-over 2

2 Fault Finding 3

3 Maintenance 5

3.1 Diaphragm Replacement 5

3.2 Spindle Seal Replacement 6

3.3 Disassembling the Change Over Valve 7

4 Technical Data 9

4.1 Specification 9

4.2 Dimensions 10

5 Spare Parts 11

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1818015-02 V2

1 Function Description

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396

25A

A. Out, when activatedB. InC. Out, when deactivated

G01

173

1A

A. Deactivated valve B. Activated valve

1.1 Application

The pneumatic three-way valve is used in thoil supply line to a separator. Oil fed to the valve goes either straight through the valve the separator or down to a recirculation line.

1.2 Working Principle

CAUTION

Entrapment hazard

Do not touch the valve spindle. It may go down and cause injury to your fingers.

1818015-02 V2 1

1 Function Description Pneumatic Change Over Valve

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015

2A

1. Hand wheel2. Air inlet3. Piston plates4. Diaphragm5. Spring6. Piston rod

1.2.1 Activated Valve

The valve actuator is pressurized by compressed air (2). The diaphragm (4) and piston rod (6) are pressed downwards and opens the valve for flow straight through.

1.2.2 Deactivated Valve

When the valve actuator is depressurized toatmospheric pressure, the diaphragm is pushed up by the spring (5). The piston rod also goes up, which closes the valve for straight through flow and opens for flow downthrough the bottom valve port.

1.2.3 Manual Change-over

By screwing the hand wheel down, the pistois forced down and the valve opens for straight-through flow.

2 1818015-02 V2

2 Fault Finding

Remedy

Fit a new diaphragm.

Examine the solenoid valve block (air) and the air supply line, and correct the fault.

Adjust the air pressure.

Fit a new seal.

wn. Turn the hand wheel to top position.

Fault Probable cause

No change-over or sluggish operation of the change over valve.

Diaphragm broken.

Air supply inadequate.

Air pressure too low.

Air leakage.

Hand wheel screwed do

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2 Fault Finding Pneumatic Change Over Valve

4 1818015-02 V2

3 Maintenance

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72A

1. Cover2. Body3. Seal washer4 Piston plate, upper5 Diaphragm6. Gasket7. Piston plate, lower8. Piston rod

3.1 Diaphragm Replacement

1. Remove the hexagon bolts and the covewith the hand wheel.

2. Remove the screws to the piston plates and the seal washer (3) and gasket (6).

3. Remove the upper piston plate and the diaphragm.

4. Reassemble in reverse order to disassembly.

CAUTION

Burn hazard

Shut off the process oil before dismantling or making any repairs. The oil may be hot and cause skin burn.

NOTE

Make sure air pressure is released before dismantling.

1818015-02 V2 5

3 Maintenance Pneumatic Change Over Valve

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A

3.2 Spindle Seal Replacement

1. Remove the pin (7) from the piston rod (6).

2. Disconnect the air connection to the actuator.

3. Loosen the screws (8) holding the actuatto the valve and lift off the entire actuatorassembly.

4. Remove the seal sleeve (2) and lift it off the spindle. Then replace the O-ring (1) seal rings (3) and spring (5) by new spares.

5. Reassemble the spindle seal in reverse order to disassembly. Fit the actuator assembly and reconnect the pin (7) to thsleeve (6). Fit the air connection. Tightenthe screws (8).

6 1818015-02 V2

Pneumatic Change Over Valve 3 Maintenance

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3.3 Disassembling the Change Over Valve

The change over valve normally needs no maintenance. If however, the valve has to bdisassembled, proceed as follows:

1. Disconnect the air connection and removthe valve from the pipe flanges.

2. Screw down the hand wheel to its end position and remove the pin (2) from therod (3).

3. Remove the flange (4) from the valve body (1).

4. The valve spindle (5) can now be pulledout for access to the valve cone.

5. Reassemble the valve in reverse order tassembly.

1818015-02 V2 7

3 Maintenance Pneumatic Change Over Valve

8 1818015-02 V2

4 Technical Data

ineral oil

Max. 150°C

Max. 1.0 MPa (10 bar)

Max. 2.0 MPa (20 bar)

Spheroidal graphite iron

ir

Max. 1.0 MPa (10 bar)

1.6 MPa (16 bar)

4.1 Specification

Valve

Media M

Media temperature

Operating pressure

Valve housing test pressure

Material valve body

Pneumatic actuator

Media A

Operating pressure

Test pressure

Ref. 748393 Rev. 11

1818015-02 V2 9

4 Technical Data Pneumatic Change Over Valve

Kv(m3/h)

Weight (kg)

Flanges acc. to

)Dh

(mm)Ds

(mm)G

(mm)

110 18 208 24.5 18 DIN

85 15 142 10.5 9.8 DIN

105 19 208 - 18.5 JIS

90 19 142 - 12.5 JIS

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2161

A

4.2 Dimensions

Dimensions

Conn. Article No. A(mm)

B(mm)

C(mm)

D(mm

40 1 1/2" 748393-82 500 125 200 150

25 1" 748393-83 475 105 170 115

40 1 1/2" 748393-84 500 125 200 140

25 1" 748393-85 475 105 170 125

Ref. 748393 Rev. 11

10 1818015-02 V2

5 Spare Parts

Remarks

s kit for pneumatic ac- Connection 25 1)

Connection 40 1) Contents, see next page

Connection 40Connection 25

Connection 40Connection 25

s kit for spindle seal Contents, see next page 1)

gasket Connection 40 DINConnection 25 JISConnection 40 DINConnection 25 JIS

h cone and pin Connection 40, L=155Connection 25. L=147

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396

26A

1. Parts recommended for 3 years of operation

Item Qty Article No. Description

1 1 1761448-031761448-04

Spare parttuator

1 748393-16748393-17

Yoke

3 1 748393-06748393-07

Sleeve

4 1 748393-05 Spare part

5 1 748393-08748393-09748393-12748393-13

Flange with

6 1 748393-10748393-11

Spindle wit

1818015-02 V2 11

5 Spare Parts Pneumatic Change Over Valve

Remarks

s kit for pneumatic ac-des:

r

s kit for spindle seal in-

G0

206

83A

Item Qty Article No. Description

2

abcdef

113312

Spare parttuator inclu

O-ringScrewSeal washeGasketDiaphragmBearing

3

abcefgh

1131141

Spare partcludes:

Seal sleeveO-ringSealingCu-washerSpringScrewPin

12 1818015-02 V2