Powell Valves Double Offset Butterfly User manual

Operation, Installation, and Maintenance

TABLE OF CONTENTS

SECTION PAGE

GENERAL DESIGN AND INFORMATION 2

INSPECTION 3

INSTALLATION 4

INSTALLATION: BOLTING REQUIREMENTS 5

OPERATION 6

REMOVAL 7

MAINTENANCE

SEAT RING 8

PACKING 9

END CAP GASKET 10

2

Double offset butterfly valves are designed having double eccentricity in order to provide a superior seal compared

to standard butterfly valves. The principle parts of the valve are the body, disc, seat, and stem making a simple

design which allows for easy maintenance. Many options and configurations are available. Some of the choices are

as listed below:

1. Different materials are available for all parts.

2. Different end designs are available such as wafer and lug (shown above and below).

3. Different operators are available such as lever arm and gear.

Lug Style

Wafer Style

GENERAL DESIGN AND INFORMATION

NOTE: See Powell “Handbook of Valve Information “ pages 3 and 4 for information on

materials of construction, SAFETY precautions, and care of valves prior to installation.

3

Pre-Installation Inspection

Powell recommends customers always inspect their valves before attempting installation in order to en-

sure the item is undamaged and meets the correct specifications.

 Check to guarantee valve has not been damaged during shipment.

 Remove the protective covering on valve ends and clean it with compressed air or a clean

rag.

Along with inspecting the valve, it is important for the customer to make certain the pipeline is clean and

ready for the installation of the valve.

 All foreign material (dirt, welding chips, rust, etc…) should be removed from the inside of

the pipeline.(1)

 The pipe flange and gasket surface should be clear of all unwanted material.

Regular Inspection

 The valve should be visually inspected when initially used and whenever the valve is used after long

periods of dormancy.

 It is important to regularly check the tightness of bolting.

 Check the tightness of the gland bolting. Most packing leaks can be fixed by tightening the packing

gland nuts. See “Packing Replacement” section for further information on tightening gland nuts..

 Confirm that there is no damage to seat, seat retainer, of body end surfaces.

*ANY STRANGE SOUNDS SHOULD BE INVESTIGATED IMMEDIATELY.*

NOTES

(1) Foreign material can scratch and damage the internals of the valve when carried by the fluid.

INSPECTION

4

Before installing valve, follow the pre-installation procedure found on page 3.

Installation Procedure:

1. Valve should be fully closed before installing.

2. Line up flow arrow on valve with preferred flow direction.

3. Gasket needs to be placed in the center of the valve in pipe flange to ensure proper sealing.(1)

4. See figures below.(2)

5. Valve may be lifted into position by strap or sling suitable for the weight of the valve by securely

attaching around body neck area. Chains or cables may only be used of valve is protected from dam-

age. Care must be exercised when attaching the lifting strap and when lifting the valve to prevent

damage to valve stem, valve actuator, or any other valve component or any injury to operator or other

nearby personnel or equipment.

6. There may not be any piping component adjacent to the valve that would interfere with the valve disc

during opening or closing operations sinc eth disc extends beyond the valve ends when the valve is

opened.

NOTES

(1) New gaskets MUST ALWAYS be used when installing the valve.

(2) Applying too much torque to the bolting can damage the gasket.

Make sure flange gaskets

are centered with the valve.

There should be enough

room for the valve to slip

into place.

Bolts should be tightened to the

recommended torque values for a

complete seal.

Ensure valve is closed when in-

stalling so as to prevent any dam-

age to the disc or seating areas.

INSTALLATION

5

INSTALLATION:

BOLTING REQUIREMENTS

Pressure VALVE THREAD LUG BODY WAFER BODY

Class SIZE SIZE BOLTS Studs Studs

QTY LG QTY LG QTY LG QTY LG QTY LG QTY LG

150 3 5/8-11UNC 4 2 4 1.75 4 2.75 4 2.5 4 5.5

150 4 5/8-11UNC 8 2 8 1.75 8 2.75 8 2.5 8 5.75

150 6 3/4-10UNC 8 2.25 8 2 8 3.25 8 3 8 6.25

150 8 3/4-10UNC 8 2.5 8 2 8 3.5 8 3 8 6.75

150 10 7/8-9UNC 12 2.75 12 2.25 12 4 12 3.5 12 7.5

150 12 7/8-9UNC 12 3 12 2.5 12 4.25 12 3.75 12 8

150 14 1-8UN 12 3 12 2.75 12 4.5 12 4.25 12 9

150 16 1-8UN 16 3 16 2.75 16 4.5 16 4.25 16 9.5

150 18 1 1/8-8UN 16 3.75 16 3 16 5.25 16 4.5 16 10.5

150 20 1 1/8-8UN 16 3.75 16 3 16 5.25 16 4.5 16 11.3

4 3.25 4 2.75 4 4.75 4 4.25 4 4.75 4 4.25

150 24 1 1/4-8UN 16 4 16 4 16 5.75 16 5.75 16 12.5

4 3.5 4 3.5 4 5.25 4 5.25 4 5.25 4 5.25

150 30 1 1/4-8UN 24 5.25 24 5 24 7 24 6.75 24 16.5

4 5 4 4.5 4 6.75 4 6.25 4 6.75 4 6.25

150 36 1 1/2-8UN 28 6.25 28 5.75 28 8.25 28 7.75 28 18.8

4 5.75 4 5.25 4 7.75 4 7.25 4 7.75 4 7.25

300 3 3/4-10UNC 8 2.25 8 2 8 3.25 4 3

300 4 3/4-10UNC 8 2.25 8 2 8 3.25 8 3

300 6 3/4-10UNC 12 2.75 12 2.5 12 3.5 12 3.5

300 8 7/8-9UNC 12 3.25 12 2.75 12 4.25 12 4

300 10 1-8UN 12 3.5 12 3.25 12 4.75 12 4.5

4 3.25 4 3 4 4.5 4 4.25

300 12 1 1/8-8UN 12 4 12 3.5 12 5.5 12 5

4 3.5 12 3 4 5 4 4.5

6

OPERATION

Valves are normally provided with lever or gear actuators as described in Powell’s But-

terfly Valve catalog. Optional motor and air actuators are also available upon request.

For lever actuated valves, the valve is in the closed position when the level is perpen-

dicular to the centerline of the pipeline. Valve is in the open position when the level is

parallel to the pipeline centerline. The disc position is also shown by the indicator plate

at the top of the valve. Valves are capable or mild throttling and indicator plates are

notched to hold the lever in the selected position.

Gear actuated valves have position indicators to show disc position.

Technical information such as valve dimensions, weights, flow coefficient (Cv) values,

pressure / temperature ratings, required torque to operate the valves, available gear

and lever information, and recommended maximum flow velocities are given in the

Powell Butterfly Valve catalog. Valves must always be operated within the applicable

pressure / temperature limits defined in the catalog to avoid valve damage and hazard-

ous conditions.

7

Heavy Hex Nuts

Studs

Flange

Gasket

High Performance

Butterfly Valve

Heavy Hex Nuts

Flow

1. The pipeline is to be shut down and pressure relieves to ensure the valve is no longer under pressure

and it is recommended that fluid also be drained from the sytem in the area of the valve. See Powell

“Handbook of Valve Information” section “First Consideration” for further precautions.

2. Rotate the stem until the valve is in the completely close state.

3. Loosen and remove the flange nuts as shown below.

4. Remove all flange studs.

5. Remove valve and gaskets.

*WARNING*

Proper protection must be used in the removal of the valve if the line fluid is hazardous or toxic, or valve

and piping must be decontaminated before removal.

REMOVAL

8

Seat Ring Bolts

Seat

Retainer

Seat Ring

Powell High Performance Butterfly Valves are designed so that they do not require regular maintenance. All parts

are internal to the valve which prevents potential for any external leakage. Regular inspections should be carried

out, however. If any leakage is found, maintenance will be required.

Seat Ring Replacement (reference drawing below)

1. Slightly open valve (disc approximately 10~15° open).

2. Remove seat ring bolts and seat retainer.

3. Remove seat ring.

4. Install replacement seat ring..(1)

5. Reinstall seat retainer and seat retainer bolts. Tighten seat retainer bolts using criss-cross pattern for

even pressure on seat ring surface.

NOTES:

(1) Handle inner seat carefully so as not to scratch or damage it.

MAINTENANCE

9

Packing Replacement

1. Loosen and remove gland stud nuts.

2. Remove gland flange.

3. Carefully lift and remove gland.

4. Using a packing extracting tool, remove the packing.(1)

5. Carefully clean the packing chamber.

6. Insert new packing.

7. Carefully reinsert gland and gland flange. The center gland flange hole should be centered around the

stem to avoid contact with stem during operation.

8. Tighten gland nuts evenly to maintain gland in level position and centered around stem. The gland

nuts are properly tightened when there is no packing leakage and valve can be operated without ex-

cessive force.

NOTES:

(1) Be careful when removing packing to avoid damaging the stuffing box or stem Any scratches or other

damage could later cause leakage.

Gland Stud Nut

Gland Stud

Packing Retainer

Gland

Packing

Gland Flange

MAINTENANCE CONT...

10

End Cap Gasket (sizes 8” and above only)

1. Remove end cap bolts.

2. Remove end cap.

3. Remove old gasket and discard.

4. Carefully clean the gasket seating area. Do not scratch or damage gasket or gasket sealing surfaces.

5. Insert new gasket.

6. Reinsert end cap.

7. Reinsert and evenly tighten cap bolts.(1)

NOTES:

(1) Too much torque on the cap bolts can cause damage to the threaded parts and to the heads of the

bolts.

.

MAINTENANCE CONT...

Powell Valves Double Offset Butterfly User manual

Powell Valves Double Offset Butterfly User manual

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