Dembla 7400 Series User manual

Instruction Manual
D Butterfly Valve
Series 7400
ouble Offset
1Feb 2009
0062
2 G/D T 3/4/5/6

CONTENTS PAGE NO.
2
1.1 Introduction 2
1.2 Scope of Instruction Manual 2
1.3 Copyrights and Modification Rights Reservation 2
2
3
4
5
6
8
7.1 Pre-Installation Checks 8
7.2 Operation 8
7.3 Lubrication 8
9
9
9.1 V-PTFE Packing 10
9.2 Double V-PTFE Packing 10
9.3 Grafoil Packing 11
9.4 Double Grafoil Packing 11
9.5 V- Low Fugitive Emission Packing 12
9.6 Grafoil Low Fugitive Emission Packing 12
13
10.1 Replacing Guide Bush (Bearings) 14
10.2 Trouble Shooting 15
15
11.1 Operation 16
11.2 Removing Hand Lever Operator from the Valve Body 16
17
12.1 Operation 17
12.2 Setting of Gear Box Type Operator 18
19
13.1 Fixing / Mounting Hand Lever on Body Set 19
13.2 Fixing / Mounting Gear Box Type operator on Body Set 19
20
14.1 Butterfly Valve Assembly Flange: - Size 2” (50mm) to 6” (150mm) 20
14.2 Butterfly Valve Assembly Flange: - Size 8” (200mm) & 72” (1800mm) 21
22
22
1.0 Foreword
2.0 Storage & Preservation
3.0 Valve Marking
4.0 Health & Safety
5.0 Unpacking
6.0 Lifting Details
7.0 Installation of Butterfly Valve
8.0 Maintenance
9.0 Replacing Gland Packing
10.0 Replacing Soft Seat
11.0 Hand Lever Type Manual Operator
12.0 Gear Box Type Manual Operator
13.0 Installation of Manual Operator
14.0 Parts Illustrated
15.0 Torque for Studs
16.0 Recommended Spare Parts
PTFE
1

1.0 Foreword
1.1 Introduction
1.2 Scope of Instruction Manual
1.3 Copyrights and Modification Rights Reservation
2.0 Storage & Preservation
Dembla High Performance Butterfly Valves are available in Flange type Designs conforming to API 609
standard. The Disc construction is Double Offset. Shafts are guided by bearing. Various seat options are
available.
This Instruction Manual covers information regarding Installation and Maintenance of Dembla's Double
Offset High Performance Manual Butterfly Valves Flange type, Series 7400.
No person may Install, Operate or Maintain Dembla Valve without 1) being fully trained and qualified in
Valve, Actuator and Accessory Installation, Operation and Maintenance 2) Carefully reading and
understanding the contents of this manual. If you have any questions about these instructions contact
your Dembla Sales Office before proceeding.
Dembla Valves Ltd. retains the Copyright on the contents of this Instruction Manual.
The total content of this Instruction Manual described here corresponds to the information
during preparation of the Instruction Manual. It is user's responsibility to refer the latest version.
All data, specifications and illustrations here are subjected to Technical Modifications and
improvements and hence Modification can be done by us at any time without any prior notice.
No claim to Modification or repair of these Valves, which have already been supplied by us, can
be made.
All Valves are dispatched in the closed/open position as ordered and it is recommended that they are left
in this position during Storage. All protective Packing should remain in position until the Valve is to be
Installed. Valve should be stored in a clean and dry environment, without disturbing company setting.
(e.g. Gland, Seat etc.) Protect it from shock & lifting damage.
If hoisting the Valve, use a nylon sling to protect the surface. Carefully position the sling to prevent damage
to Actuator tubing and any Accessory. Also, take care to prevent people from being injured in case the hoist
or rigging slips unexpectedly. For Valve weight refer Valve Packing slip.
!Caution
2

3.0 Valve Marking
1) Valve name plate attached on Valve by riveting carrying all Valve Identification Information.
2) Markings like Valve Size, Rating, Material etc. are as cast on Valve Bodies.
3) Valve Serial No. punched on Valve Body Flange for Valve Traceability.
4) If the product is not CE marked, Then name plate is also without CE mark.
3
Name plate for
Series:-7400 Valves
0062
INDIA
II 2 G/D T *

4.0 Health & Safety
1) Before attending to Valve Installation / Maintenance, the Instruction Manual must be compulsorily read
and understood properly.
2) Valve must be operated by qualified personnel.
3) Ensure that the operator handling these Valves must follow Safety and Accident Prevention Rules and
Regulations.
4) Follow the Safety Instructions before Installation, Maintenance or removing the Valve.
5) Always wear protective gloves, clothing and eyewear when performing any Installation operations to avoid
personal injury.
6) All Safety Messages such as Cautions, Warnings and Notes are highlighted in this Instruction Manual
which must be strictly followed to avoid any possibility of arising danger / risk of damage to the
equipment / person's life
7) No Liability on Manufacturer for any wrong handling, improper commissioning and wrong assembly.
8) Line must be fully drained and de-pressurized before Installation or Maintenance of Valve.
9) Never handle Valves that have been used on harmful substances unless they have been completely
decontaminated and certified safe to handle.
10) Due to the large physical Size and weight of some Size of this product, always use correct lifting methods
and equipment when Installing , removing and maintaining the product:
Use lifting lugs on the body, wherever provided.
Valve without lifting lugs-use chains or slings wrapped around the body.
Do not attempt to lift the Valve using the Sealant Fittings, Gear Unit, Handwheel, Actuator, or the Valve
Stem.
11) If the processes or environments that the products are used in are likely to cause temperature (high or low)
that may cause injury to person if touched, then adequate Insulation / protection must be fitted.
It is recommended that the insulation allows easy access for Maintenance, to the Sealant Fittings, and to
the Valve operator.
12) Valve must be protected from earthquake loading, traffic & wind.
13) No Modification / Conversions are allowed without written authorization from Dembla Valves Ltd.
Rise in temperature on surface of Valve Body depend on working Media. End user must be
maintaining the surface temperature & it should not go beyond marking temperature on Valve
(Name Plate).
4
!Warning
!Warning

5.0 Unpacking
For Carton
For Wooden Box
·
·
·
·
·
·
·
·
·
·
·
Keep Carton in position (Carton up side should not be down ).
Cut plastic strip properly which is tied around Carton & remove it. (White in colour).
Cut cello tape properly which is stuck on Carton opening.
Open Carton properly.
Remove foam properly along with polythene wrapping.
Lift the Valve properly & keep on clean & dry place
Keep Wooden Box in Position ( upside of Wooden Box should not be down ).
Cut iron strip properly which is tied around Wooden Box & remove it.
Remove nail properly from top cover with proper equipment.
Loosen and remove Valve fixing nut (from inside of Box).
Lift the Valve properly as shown in figure 1
5

6.0 Lifting Details
Valve should be lifted by using chain or bearer cables as shown in figure 1. (Take care that
Valve should not damage while handing).
6
Fig .1

·
·
·
·
·
·
·
·
1) An occasional cleaning of Valve Stem will prevent dirt or grit being carried away into the Packing.
2) Vary air lines and fitting to the Actuator to ascertain actual Travel Scale Indication.
3) Check all air lines and fitting to the Valve Actuator & Accessories for air Leaks.
4) Ensure that the combined action of Controller, Positioner and Valve provide the desired Valve
Stem Movement. Also ensure the required fail safe position of Control Valve.
Always wear protective gloves, clothing, and eye ware when performing any Installation
operation to avoid personal injury.
Valve should be used by End-user with same pressure & temperature rating which was given in
Valve Marking (Name Plate) If there is any change please contact Dembla Sales Office.
Avoid personal injury or property damage caused by components dropping .With the Valve or
Actuator upside, components may drop during disassembly or assembly. Be careful not to
position yourself below the Valve in the path of falling parts.
Personal injury could result from Packing Leakage. Valve Packing was tightened prior to
shipment, but should there be any Gland Leakage after Installation, further tightening, just
enough to stop Gland Leak is required. Excessive tightening will disturb Valve Calibration.
Our Valves can not be used for Defence, Nuclear, Telecommunication, Marine, Railway and
Laboratory & Mines.
Our Valve is valid for atmospheres having pressure ranging for 0.8 bar to 1.1 bar and
temperatures ranging for -20ºC to +60ºC
Earthing facility must be provided by the end user before operating the Valve.
Equipment should not be used for dead end service
After the Valve has been Installed, make a final check of the following :-
·In case of Leak, presence of high temperature may be dangerous to the person s life.
Equipment to be used as per intended and not misused / improperly used to avoid dangerous
effects such as over load ,over heating ,stress corrosion cracking, etc.
·
7
!Warning
!Caution

7.0 Installation of Butterfly Valve
7.2 Operation
7.3 Lubrication
7.1 Pre-Installation Checks: (Before Installing any Butterfly Valve)
(1) Inspect it for any shipment damage and for foreign material that might have collected during Packing and
shipment.
(2) Blow out all pipelines to remove pipe scale-chips, welding-slag, and other foreign materials.
(3) Install the Valve using accepted piping practices.
(4) Install the Valve according to flow direction marked on the Valve.
(5) Use self centering Gasket.
(6) Install the Control Valve preferably in a straight run of pipe away from bends or sections of abnormal
velocity.
(7) Incorrect pipe alignment will cause interference between the disc edge and line Flange face, excessive
torque and damage to disc and seat, resulting into Seat Leakage.
(8) Do not try to Install Valve between line flanges having inadequate gap. This may cause damage to some
Valve parts. If Valve is in fully open position, it will impact the Flanges and damage the disc edge.
(9) No butterfly Valve should be attempted to Install when disc in open condition. The butterfly Valve can be
inserted between line flanges in fully close position.
(10) Glands are factory tightened and checked for Leakage however if there is any Gland Leak in Valves, the
Gland may be further tightened just enough to stop Leakage. Excessive tightening should be avoided
(11) Connect the Valve in pipe line with the standard connections.
Valve closes with clockwise rotation of the Valve Shaft. Valve is fully closed when disc is parallel to Seat
Ring.
The Valve Body set does not require any routine lubrication. However Valve operator may require
lubrication which is to be referred in the Part-II Manual Operator Section of this Instruction Manual.
8

8.0 Maintenance
·
·
·
·
·
·
ning so that
the Body to bonnet joint will with stand test pressures and application service condition, before tightening
nuts make sure that Plug & Stem assembly is properly aligned with Seat Ring.
11) For the Installation of Gland Packing refer following 9.1 to 9.6
12) Mount the Actuator & Connect Stem Connector as specified in the “Reassembly of Actuator on Valve
Body” Refer Section 11.0 of this Manual.
Avoid personal injury or damage to process system from sudden release of pressure of
process fluid.
Before starting dis-assembly Use by-pass Valve or completely shut off the process to isolate
the Valve from process pressure. Drain fluid from both ends of the Valve.
Disconnect all operating lines providing air pressure, electric power or a control signal to the
actuator.
Any Gasket once removed should be replaced by a new one upon re-assembly. This is
necessary to ensure a good seal since the used Gasket may not seal properly.
Earthing facility and Valve parts (Bush) should be checked periodically by the end user.
Equipment should be cleaned regularly.
9.0 Replacing Gland Packing
1) Isolate the Control Valve from line pressure & release the pressure.
2) Remove Actuator from Valve Body as shown in section 8.1 “Removing Actuator from the Valve Body.
3) Remove the Nuts from Body Studs on Bonnet and lift the Bonnet carefully off the Body. If the Valve Plug &
Stem assembly starts to lift along with Bonnet, use a brass or Nylon hammer on the end of the stem & tap it
back down.
4) Remove the Valve Plug & Stem assembly from the Body.
Handle the Plug & Stem carefully to avoid the damage at seating surface of & Stem diameter.
5) Unscrew and remove Gland Flange Nut.
6) Remove Gland Flange.
7) Push out Gland Packing from the Bonnets bottom side Gland Packing& Spreader carefully take out by
using a rounded rod or other tool that will not scratch but clean the stuffing box wall.
8) Install Plug & Stem assembly. Then slide the Bonnet over the stem and on to the Body Studs.
9) Install new Packing Seal & Metal Gland Parts according to the appropriate arrangement.
10) Lubricate the Body Studs and Install the nuts. Use accepted bolting procedure during tighte
Set the Bonnet on a protective surface to prevent damage to the Bonnet Gasket surface.
9
!
Caution

9.1 V-PTFE Packing
9.2 Double V-PTFE Packing
This Gland Packing consists of 1 Rear Packing Spreader, 1 set of V-PTFE Gland Packing and 1 Front
Packing Spreader.
(1) Place the V-PTFE Gland Packing set in the Body after 1 Rear Packing Spreader followed by Front Packing
Spreader as shown in Fig. 9.1 Lubrication is not required.
(2) Insert the Gland Bush.
(3) Insert the Gland Flange on Gland Studs and tighten their Nuts to specified torque.
Push each V-PTFE Packing carefully inside to avoid the Packing lip to bend towards the outer
side.
10
PACKING SPREADER (REAR)
V-PTFE GLAND PACKING
GLAND STUD
PACKING SPREADER (FRONT)
NUT
VALVE SHAFT
GLAND BUSH
GLAND FLANGE
!Caution
V-PTFE GLAND PACKING (of 1st set)
FRONT PACKING SPREADER (of 2 nd set)
V-PTFE GLAND PACKING(of 2 nd set)
GLAND STUD
NUT
GLAND BUSH
GLAND FLANGE
VALVE SHAFT
REAR PACKING SPREADER (of 2 nd set)
FRONT PACKING SPREADER (of 1st set)
REAR PACKING SPREADER (of 1st set)

This Gland Packing consists of 1 set of Front and Rear Packing Spreader, 1 set of V-PTFE Gland Packing,
2 set of Front and Rear Packing Spreader & 2 set of V-PTFE Gland Packing.
1) Place the 1 set of V-PTFE Gland Packing after Rear Packing Spreader of 1 set followed by the Front
Packing Spreader of 1 set.
2) On the Front Packing Spreader of 1 set place the 2 set of V-PTFE Gland Packing after Rear Packing
Spreader of 2 set followed by the Front Packing Spreader of 2 set.
3) Insert the Gland Bush.
4) Insert the Gland Flange on Gland Stud and tighten their Nuts to specified torque.
st st
nd nd
st st
st.
st. nd
nd nd
9.3 Grafoil Packing
9.4 Double Grafoil Packing
11
VALVE BODY
GRAFOIL GLAND PACKING
VALVE SHAFT
GLAND STUD
GLAND BUSH
NUT
GLAND FLANGE
GRAFOIL GLAND PACKING
GLAND STUD
GLAND BUSH
NUT
GLAND FLANGE
LANTERN RING
GRAFOIL GLAND PACKING
VALVE SHAFT

9.5 V-PTFE Low Fugitive Emission Packing
9.6 Grafoil Low Fugitive Emission Packing
12
REAR PACKING SPREADER
V-PTFE GLAND PACKING
GLAND STUD
FRONT PACKING SPREADER
VALVE SHAFT
GLAND BUSH
GLAND FLANGE
WASHER
SPRING WASHER
NUT
VALVE SHAFT
GRAFOIL GLAND PACKING
GLAND STUD
GLAND BUSH
NUT
SPRING WASHER
GLAND FLANGE

10.0 Replacing Soft Seat.
For maintenance or replacement of Soft Seat, operator and bracket need not be dismantled.
Soft Seat must be replaced once it is dismantled.
Soft Seat should be Installed preferably with the Valve in close position.
With Soft Seat, Flexible Metal Seat & Fire Safe Seat are also available as per requirements.
(1) Isolate the Control Valve from line pressure and release the pressure.
(2) Remove the complete Valve from the pipe line.
(3) Unscrew and remove the Seat Retainer screws.
(4) Take out the Seat Retainer.
(5) Take out Soft Seat.
(6) Replace the Soft Seat with new one and reinstall the Seat Retainer.
·
·
·
13
FLEXIBLE PTFE SEAT
ARRANGEMENT
(soft seat)
FIRE SAFE SEAT
ARRANGEMENT
FLEXIBLE METAL SEAT
ARRANGEMENT
Note
Note

10.1 Replacing Guide Bush (Bearings)
(1) Isolate the Control Valve from line pressure
And release the pressure.
(2) Remove the complete Valve from the pipe line.
(3) Remove Gland Packing refer. 9.0 to 9.6
(4) Unscrew and remove the Seat Retainer Bolt.
(5) Take out the Seat Retainer.
(6) Take out Soft Seat .
(7) Remove the Locking Pin from the Disc by
slight hammering. (Upper & Lower)
(8) Remove Front Shaft.(Disc should be
Supported)
(9) Loosen and remove Bottom Cover Bolt.
(10) Remove Bottom Cover.
(11) Remove Rear Shaft.
(12) Remove Disc properly.
(13) Keep the Disc in a safe place away from dust and scratches.
(14) Now slowly remove the Guide Bush by slightly hammering by
a pusher tool avoiding scratches in the Valve Body.
(15) Replace the Guide Bush with new one.
(16) Insert the Disc in the Valve Body and maintain its position
(17) Insert Rear Shaft from bottom side.
(18) Install Bottom Connection & Bolt it.
(19) Insert Lock Pin in Rear Shaft and Disc properly by slight hammering.
(20) Insert Front Shaft from top.
(21) Insert Lock Pin in Front Shaft and Disc properly by slight hammering.
(22) Install Gland Packing refer. 9.0 to 9.6
(23) Place the Soft Seat followed by Seat Retainer along with Its clamping screws.
(24) Tighten the Seat Retainer clamping screws.
(25) The Valve is ready to be placed in the pipeline.
14
'A'
'B'
Detial 'B'
Detial 'A'

10.2 Trouble Shooting
11.0 Hand Lever Type Manual Operator
Hand Lever arrangement provides latching system in open, closed and other eight equally
spaced intermediate positions. A pointer indicates the position of disc and an additional lock facility is
provided to prevent unauthorized Valve operation. Lever operators are provided on Size 2" (50mm) to 6"
(150mm) only. For Size 8" (200mm) and above, Gear Box Type Operators are Recommended.
Series 'H'
15
HANDLE
LEVER
SPRING
RIVET
DIAL
DIAL SCREWS
MOUNTING
BRACKET
GRUB SCREW
MOUNTING
BRACKET
MOUNTING
BRACKET
BOLTS NUTS
POINTER
LEVER
1
Condition Possible Cause Corrective Action
Gland Leakage
Seat Leakage
Valve does not
Open / Close fully
Opening / Closing
torque excessive
Gland Nut loose
Worn out Packing
2
3
Limit stop for Closed position stop got
disturbed
Sealing edge of Seat damaged
Valve pressurized to high pressure
Fluid is abrasive and eroding away the
components
Limit stop got disturbed
Foreign object got stuck up between
Disc and Seat
Disc to shaft connection failed
4
Excessive dirt accumulated at the
components
Shaft , Bearings or seat worn out
Adjust Gland Nut
Replace Gland Packing
Adjust limit stop of Gear
operator
Replace Soft Seat
Reduce line pressure to rated
pressure
Replace the worn out component
of valve with material suitable for
abrasive media
Adjust limit stop
Open the Valve and clean the line
/ Valve to remove foreign object
Replace Disc Pins and/or Shaft
Clean the components
Replace the worn out
components
Sr. No.

11.1 Operation
11.2 Removing Hand Lever Operator from the Valve Body
To operate the Hand Lever, hold the handle and squeeze the Lever to compress the Lever Spring. This is
done to dis-engage the Lever from previously held position. Now rotate the handle slowly with the
compressed Lever Spring position to the required Valve position and release the Lever in the slot or notch
provided in the Dial.
(1) Drain the flow and release the pipeline pressure.
(2) Close the Valve.
(3) Loosen the Grub Screw.
(4) unscrew the Mounting Bracket Bolts which is connected to Valve Body.
(5) Remove the hand Lever operator from the Valve Body along with the Mounting Bracket.
(6) To assemble follow the reverse sequence.
·
·
Handle should be moved slowly to close the Disc of the Valve. Sudden closing may cause
pipeline pressure to surge and may risk damage to the equipment / person's life.
Before releasing the lever, check that the Lever is positioned and engaged in the slot / notch
provided in the Dial. If the Lever is not engaged then the pipeline pressure can cause the Lever to
rotate and hence Valve will close suddenly and pipeline pressure may surge, risking damage to
the equipment /person's life.
Pipeline pressure while removing the operator may cause the Valve to close suddenly and
pipeline pressure may surge, risking damage to the equipment / person's life. To avoid this,
drain the flow and release the pipeline pressure before removing the operator.
16
!Caution
!Caution

12.0 Gear Box Type Manual Operator
12.1 Operation
quarter turn Gear operators offer simple and reliable Manual positioning of the Butterfly
Valves for 0 to 90° operation. These operators consist of single stage worm and worm wheel arrangement
housed in a robust weather-proof cast iron housing. Adjustable mechanical stoppers are provided to the
operator within ± 5% of the extreme positions. A mechanical position Indicator is provided on these units
to show the Valve position. Units are grease filled in the factory and does not require further lubrication.
Thrust bearings provided takes axial thrust in operation. Sturdy design provides long life and maintenance
free services. The high Gear ratios enable the minimum input efforts for high torque conditions.
To close the Valve, Rotate Gear operator handwheel clockwise.
To open the Valve, Rotate Gear operator handwheel anti-clockwise.
Series 'MOR'
17

12.2 Setting of Gear Box Type Operator
The Open and Closed position stops prevent the operator from rotating beyond the open and closed
position of the Valve respectively. Each stop is adjustable. If the operator is factory-mounted on the Valve,
the stops are preset, and do not require any further adjustment.
If the operator is not factory mounted on the Valve, or if the operator has been removed, the stop will
require adjustment as described below.
(1) Loosen the Lock Nut by rotating it anti-clockwise on closed position stop screw (stopper) to about 2 turns.
(2) Turn the hand wheel so that the Valve is in the closed position.
(3) Turn the Closed position stop screw (stopper) clockwise until it touches the Gear inside of the operator.
(4) Hold the Closed position stop screw (stopper) head from turning, and tighten the Lock Nut by rotating it
clockwise.
(1) Loosen the lock nut by rotating it anti-clockwise on Open position stop screw (stopper) to about 2 turns.
(2) Turn the Hand Wheel so that the Valve is in the open position.
(3) Turn the Open position stop screw (stopper) clockwise until it touches the Gear inside of the operator.
(4) Hold the Open position stop screw (stopper) head from turning, and tighten the Lock Nut by rotating it
clockwise.
To adjust closed position stop :( Refer Drg.No.2)
To adjust the Open position stop: (Refer Drg.No.2)
18

13.0 Installation of Manual Operator
13.1 Fixing / Mounting Hand Lever on Body Set
13.2 Fixing / Mounting Gear Box Type Operator on Body Set
(1) Insert the Mounting Bracket in the Shaft.
(2) Align the Hand Lever on the top of the Valve Shaft by using Lever slot exactly sit in
the Valve Shaft square provided.
(3) Insert and then tighten the Grub Screw to fix up the Hand Lever with the Valve Shaft.
(4) Tighten the Dial Screw.
(5) Place Lever operator and Valve in closed position.
(6) Mount the Mounting Brackets on the Valve Body by the using Mounting Bracket Bolts.
(7) Check Open and closed positions of the Hand Lever without the flow and pressure.
(1) Fix up the Pinion Shaft with Gear operator by using Key.
(2) Place the Gear operator along with the Pinion Shaft on the Mounting Bracket.
(3) Align & fix the Valve Shaft with Pinion Shaft accurately.
(4) Fix the Gear operator with Bracket by using Bolts.
(5) Fix the Gear operator along with Mounting Bracket by using Bolts on Valve Body.
19