APV TWIN Series Instruction manual

www.australianpipelinevalve.com.au
INSTALLATION, OPERATION & MAINTENANCE MANUAL
EXPANDING SEAL PLUG VALVE
DOUBLE BLOCK & BLEED
API6D
TWIN
SERIES

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AUSTRALIAN PIPELINE VALVE BRAND RANGE -CATALOGUES
APV FAMILY OF BRANDS RANGE - CATALOGUES
COMPLETE
PRODUCT LINE
“Australian Pipeline Valve
produces isolation,
control and flow reversal
protection products for
severe and critical service
media in utility, steam,
pipelines, oil & gas
and process industries.
APV valves and pipeline
products form the most
competitive portfolio
in the market.”
Oilfield Products
Valves & Wellheads
Gate, Globe & Check
Valves - Forged Steel
Plug Valves Lubricated,
Sleeved & Lined
Gate, Globe & Check
Valves - Cast Steel
Diamond Gear
Gearboxes
Flowturn Gate, Globe
& Check Valves
Flowturn
Instrument Valves
Flowturn Ball Valves
Multiway & Deadman
Flowturn Strainers
& Sight Glasses
Supercheck
Wafer Check Valves
Superseal
Butterfly Valves
Steamco
Steam Valves
Superseal
Industrial Ball Valves
TwinLok Tube Fittings Uniflo Check ValvesTorqturn Actuators
Ball Valves Floating
& Trunnion Mounted
Ball Valves
Floating Small Bore
Ball Valves
Special Service
Product Brochure
Contact us for your local stockist/distributor

Introduction 2-5
Safety Information 6-7
1.0 Preservation And Storage 8
1.1 Storage 8
1.2 Periodic maintenance during storage 8
1.3 Environmental considerations 8
2.0 Installation 9-13
2.1 Valve preparation 9
2.2 Valve installation 9-10
2.3 Maintenance prior to flushing 10
2.4 Flushing the pipeline 10-11
2.5 Maintenance post flushing 12
2.6 Commissioning 13
3.0 Operation 13-15
3.1 Pressure Test 14
3.2 Optional - “Differential Thermal Relief” - Bleed System 14-15
4.0 Removal From Line 16
5.0 Gearbox Removal 16
6.0 Valve Disassembly 17
7.0 Maintenance 18-19
EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
INDEX
Australian Pipeline Valve - Installation, Operation and Maintenance Manual 1
© Copyright Australian Pipeline Valve 1990 - 2018 Edition
Catalogues, photos, brochures and technical publications are the exclusive property of Australian Pipeline Valve.
Any unauthorised reproduction in total or in part, shall result in prosecution. Products and data sheets in this publication are subject
to change at anytime without notice. Australian Pipeline Valve reserves the right to carry out amendments to products and materials.

Australian Pipeline Valve - Installation, Operation and Maintenance Manual2
INTRODUCTION
The majority of this information is common knowledge to experienced steel valve users. When properly
installed in applications for which they were designed, APV valves will give long trouble free service. This
instruction is only a guide for installation, operation and minor maintenance. A professional APV approved
valve engineering facility should be utilised for reconditioning and minor repairs.
RESPONSIBILITY FOR VALVE APPLICATION
The User is responsible for ordering the correct valves. APV Valves are to be installed in the observance of
the pressure rating and design temperature. Prior to installation, the valves and nameplates should be
checked for proper identification to be sure the valve is of the proper type, material and is of a suitable
pressure class and temperature limit to satisfy the applications requirements.
RECEIVING INSPECTION AND HANDLING
Valves should be inspected upon receipt to determine:
- Compliance to purchase order requirements.
- Correct type, pressure class, size, body and trim materials and end connections (this information may
be found on the nameplate or may be stamped on the body of the valve).
- Any damaged caused during shipping and handling to end connections, hand wheel or stem.
Note
We do recommend that this entire document be read prior to proceeding with any
installation or repair. Australian Pipeline Valve and it’s parent company take no
responsibility for damage or injury to people, property or equipment. It is the sole
responsibility of the user to ensure only specially trained valve repair experts
perform repairs under the supervision of a qualified supervisor.
Do not use any valve in applications where either the pressure or temperature is
higher than the allowable working values. Also valves should not be used in service
media if not compatible with the valve material of construction, as this will cause
chemical attacks.
The End User is advised that misapplication of the valve may result in injuries or
property damage. A selection consistent with the particular performance
requirements is important for proper application and is the sole responsibility of the
end user.
EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
MODEL TWIN EXPANDING SEAL PLUG VALVE NON LUBRICATED DOUBLE BLOCK AND BLEED
DOUBLE BLOCK AND BLEED SOLUTIONS
• Permanent integral thermal relief and bleed function
• In-line mainternance in case of seal replacement
• Very short installation space required
• Double isolation function, according API-6D/ISO14313
• Only 1 actuator required to operate the valve
Unlike other valve types, the APV TWIN Twinseal style Dual Expanding
Twinseal style plug valve creates an optimum seal without causing any
abrasion and wear, providing a ‘zero-leakage’ solution, upstream and
downstream ensuring a long life-time of the seals and valve, as well as a
low opening and closing torque. This unique design is combined with a
bleed function, all in one valve, saving space as well as providing a
reliable, safe and economical solution.
PRODUCT STRUCTURAL FEATURES
Used in various industries such as petroleum, chemical industry, chemical
fertiliser, power industry etc. Class 150 - 1500LBS and working
temperature of -29~180°C.
MAIN STRUCTURAL FEATURES
• The Twinseal style double expanding plug valve has a rugged structure, reliable sealing, excellent
performance and exact tolerances.
• Sealing rings around the valve plug provide the seal. It has a unique design incorporating machined and
pressed sealing rings.
• Bi-directional, double block and bleed.
OPERATION PRINCIPLE
When the hand wheel is turned, the plug will rotate toward the closing direction for 90 degree turn
closing, the plug will then be firmly seated after moving downward into its closing position.
When the hand wheel is turned inversely, first of all the plug will move upward and the valve plug and
valve seat will be separated till the valve plug is turned 90 degree driven by the plug and finally the bore
of the plug will be in alignment with the channel of valve body.
The advantage of this type of valve is during the opening and closing of the valve, the plug and valve seat
are separated and there is no friction, thus the sealing face experiences no abrasion in the process, at the
same time the soft seal is applied for sealing so that there will be no leakage in the process of closing.

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
PERFORMANCE SPECIFICATION TECHNICAL SPECIFICATION
Class (MPa) Shell Test (MPa) Seating Test Suitable Suitable Operator Handwheel, bevel gear,electric-actuated
Temp. Medium
150 3.0 2.2
180°C* Water oil
and gas
Design Standard API599, API6D, ISO 14313
300 7.5 5.5 Face to Face ASME B16.10
600 15.0 11.0 Flange End ASME B16.5
900 22.5 16.5 Test and Inspection API598, API6D
* High/ low temperature available up to 2500 Class.
Non-slam
The operator is self locking so that line pressure
cannot force the plug to rotate. This prevents
slamming and risk of injury.
Tight shut off
When the valve is closed, the seating segments are
wedged tightly between the plug and body metal
to metal. The soft seat material is compressed into
the recessed groove. The design does not require
springs or pressure to effect a seal.
Double block and bleed and zero leakage
The Twinseal valve provides upstream and
downstream seal in both directions and a bleed
point is then provided between the two seats, to
prove no leakage.
Zero-leakage
The Twinseal meets the demands of frequent
cycling and verifiable, reliable zero leakage with
positive shut-off upstream and downstream.
Zero wear
Twinseal valves provide positive shut-off with
zero leakage.
The design of the valve ensures that during
opening and closing the seals are not in contact
with the body. Only at the last stage of closing
does the seal contact the body - and then the
force is compression only.
Every turn of the handwheel retracts the seals
from the body.
That means no wear to the seals and long life.
Large port
Twinseal valves have a nominal plug port of 60
- 70% thus effecting minimum pressure drop. True
circular full port also available.
Closing Operation

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
MAIN PARTS MATERIALS
No. Part Name Material
1 Body ASTM A216 - WCB, ASTM A351 - CF8, CF8M, CF3, CF3
2 Lower Bonnet ASTM A216 - WCB, ASTM A105, ASTM A351 - CF8, CF8M, CF3, CF3M
3 Bearing Assembly
4 Drain Valve Assembly
5 O-Rings NBR, PTFE, VITON
5A Gasket SW316 + Graphite
6 Gasket Spiral Wound
7 Bolt ASTM A193 - B7, A320 - B8, A193 - B8M
8 Nut ASTM A194 - 2H, A194 - 9, A194 - 8M
9 Plug ASTM A216 WCC+ENP, ASTM A182 - Gr. F6a, ASTM A182 - F22, ASTM A351 - CF8, CF8M, CF3, CF3M
10 Disc ASTM A182 - Gr. F6a, ASTM A182 - F22, ASTM A351 - CF8, CF8M, CF3, CF3M
11 Bonnet ASTM A216 - WCB, ASTM A351 - CF8, CF8M, CF3, CF3M
12 Bearing Assembly
13 Slip Sealing Ring Viton, PTFE
14 O-Rings NBR, PTFE, VITON
15 Packing Flexible graphite + stainless steel, PTFE
16 Gland ASTM A216 - WCB, ASTM A351 - CF8, CF8M, CF3, CF3M
17 Yoke ASTM A216 - WCB, ASTM A351 - CF8, CF8M, CF3, CF3M
18 Slide Bushing ASTM A216 - WCB, ASTM A105, ASTM A351 - CF8, CF8M, CF3, CF3M
19 Stem/Back Stem ASTM A182 - Gr. F6a, ASTM A182 - 316
20 Handwheel ASTM A436 Gr. 60 - 40 - 18, A216 - WCB
21 Yoke Nut ZQA 19 - 4
22 Guiding Stud ASTM A182 - Gr. F6a, ASTM A182 - F22, ASTM A351 - CF8, CF8M, CF3, CF3M
23 Pin ASTM A182 - Gr. F6a, ASTM A182 - F22, ASTM B637-718 Inconel, ASTM A351 - CF8, CF8M, CF3, CF3M
24 Sealant Nipple Assembly
BLOCK & BLEED:
DBB - Double Block and Bleed , method to test seat integrity with valve closed while under pressure.
DIB - Double Isolation and Bleed, Bi-Directional seating. API6D definition of redundant sealing surfaces
in both flow directions.
Side view End view

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
SAFETY INFORMATION
The following general safety notices supplement the specific warnings and cautions appearing elsewhere
in this manual. They are recommended precautions that must be understood and applied during operation
and maintenance of the equipment covered herein. This manual provides instructions for storing, general
servicing, installation and removal of ball valves.
Do not attempt to disassemble a valve while there is pressure in the line. Make sure
both upstream and downstream pressures are removed. Disassemble with caution in
the event all pressures are not relieved.
To prevent valve distortion, inefficient operation, or early maintenance problems,
support piping on each side of the valve.
• A valve is a pressurised device containing energised fluids and should be handled
with appropriate care.
• Valve surface temperature may be dangerously too hot or too cold for skin contact.
• Upon disassembly, attention should be paid to the possibility of releasing
dangerous and or ignitable accumulated fluids.
• Adequate ventilation should be available for service
• Ensure that all fluid ports are connected or closed as necessary before applying
pressure to equipment.
• Use proper lifting and supporting equipment to protect personnel and equipment.
• DO NOT loosen any fasteners, connections or attempt removal until all pressure
and mechanical loads are isolated and/or removed from the system.
• For sour service containing H2S, ensure that valve installed complies with NACE
MR0175.
• For applications concerned with external fire hazards, use valve in compliance
with API6FA/ API607

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
APV and it’s resellers refuse any liability for damage to people, property or plant as well as loss of
production and loss of income under any circumstances but especially if caused by: Incorrect installation
or utilisation of the valve or if the valve installed is not fit for the intended purpose. It is the sole
responsibility of the client to ensure the valve type and materials are correctly specified.DURING
OPERATION BEAR IN MIND THE FOLLOWING WARNINGS:
a- The graphoil packing and body gasket is very brittle: any twisting or bending shall be avoided.
b- The internal parts of valves (ball, stem, seats) shall be handled with care avoiding scratches or surface
damage.
c- All tools and equipment for handling and supporting internal critical sealing parts shall be coated with
soft materials.
d- Seats & seals usually include Viton, Devlon, Nylon & Teflon, hence high temperatures and some
chemicals will damage sealing components.
e- Never part open valve, valve must be fully open of fully closed or else the seats will be damaged.
For all operations make reference to position number on part list of the applicable drawing. The drawing
in the Appendix is a general drawing only, for more accuracy refer to the as-built drawings supplied with
the order.
SCOPE OF INSTALLATION ACCORDING TO THE TYPE OF FLUID
(DANGEROUS FOR THE ENVIRONMENT OR HUMAN HEALTH)
Group 1 Classification
- The incorporation of additional safety elements “Double packing” is recommended for the range of
products included in Group 1.
- The use of valves without additional safety devices in Group 1 will be the responsibility of the user or
the purchaser, as well as the advisability of installing leakage detection systems.
Group 2 Classification
- Carbon steel valves will not be used in corrosive fluid lines.
Do not use the ball valve in process conditions where the pressure, temperature,
media and other technical conditions exceed the limitations set by the valve’s
specifications. When handling fluids that could cause damage to human health, the
environment or property, the necessary safety precautions to prevent risk must be
taken.

1.0 PRESERVATION & STORAGE
1.1 STORAGE
a- If storage in the field for a long time before installation is necessary, it is suggested to put valves in a
dry and/or covered place. In this case the packaging and end covers integrity is especially important.
b- All the valves are supplied with special plastic ends to cover and protect the internal parts. We
recommend you do not remove them during storage period.
c- Valves should be left in the open position (unless actuated and set fail closed).
1.2 PERIODIC MAINTENANCE DURING STORAGE
In case of extended storage, the valves must be inspected and maintained as follows:-
• External surfaces must be inspected to ensure no damage to flange faces, paint finish etc. In case of
the presence of rust and/or damaged painting, the area must be cleaned by brushing, degreasing &
repainting.
• The protection must be restored following the instruction indicated from APV in accordance with the
painting cycle used.
• Without any ball movement, the internal surface of the valves must be inspected to check the complete
absence of dust, rust, foreign matters and the integrity of lubricant coat. If not satisfactory then clean
and lubricate the internal part using a nebulised lubricant. Do not leave any lubricant on the seat itself
or else the seat may attract debris which in turn could damage the seat.
• After cleaning and lubrication the ball must be operated (close/open complete stroke).
• The ball must be kept in the full open position during installation.
• The end of the valve must be protected using the same end covers.
• We recommend you tropicalise bore and ends of valves if stored in humid or salt air environment.
Grease bore with valve full open so no grease is applied to soft seat inserts.
1.3 ENVIRONMENTAL CONSIDERATIONS
According to ISO 14000 regulations and the environmental policy of APV the recyclability of the
components that form part of APV valves is as follows:
Recyclable components:
Metal parts, PTFE (hard), plastic plug (low-density polyethylene).
Non-recyclable components:
PTFE mixed with other compounds (glass-fiber, graphite, etc.), nylon, graphite and graphite mixed with
metal.
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
2.0 INSTALLATION
Orientation
APV DB&B expanding plug valve may be installed in any position.
Flow direction
The APV plug valve design is bi-directional. Flow shut-off is achieved equally on both sides of the plug
in-dependent of flow direction.
Note: The use of a Differential Thermal Relief (DTR) does result in a preferred flow direction.
2.1 VALVE PREPARATION
a- Remove the ends protectors and check accurately the status of the valve as indicated in point 1.2.
b- Prior to shipment, a preservative/corrosion inhibitor may have been applied to the inner body of the
valve. This preservative/corrosion inhibitor can be removed with a solvent, provided the solvent used
does not affect the seats/seals used in the valve.
c- Do not operate the valve until the following procedures have been fully applied:
• Clean internal conduits.
• After cleaning the ball must be operated (one complete stroke).
• During installation the ball must be kept in the fully open position.
2.2 VALVE INSTALLATION
a- To handle the valve use body lugs if applicable or suitable eyebolts. Never handle the valve by yoke or
using the lever or actuator or gear box eye bolts. Never lift from bore of valve.
Do not lift the valve
using only one lifting lug.
b- The end protectors must be removed only immediately before installation. If one of end is not
connected to the line for a period of longer than half a day the opened end shall be securely sealed
with plastic or wooden cover.
c- For butt weld type valves take care for the following: If brushing or grinding, seal valve conduit (bore)
to prevent damage. At the end of such operation clean accurately the conduit. The welding procedure
and post-weld treatment shall be performed taking into account the allowable maximum temperature
for seats and seals. The welding sequence shall be pre-planned in order to give an acceptable piping
load to the valve. Leave valve in full open position to reduce temperature transmission to soft seats. For
valves up to 80 NB (3”) use temperature measuring strips. Ensure temperature of body does not go
above 180
° C.
d- At the end of installation lock the valve full open in order to avoid any movement of the ball before
flushing the pipeline.
e- Valves will operate at any angle horizontally or vertically, although it is recommended you install
valves in a vertical position with stem pointing upwards for ease of operation, inspection and
accessibility.

f- Plug valves are usually bi-directional, and therefore may be installed in either direction. In some cases,
ball valves such as ‘metal to metal’ and low temperature valves may be unidirectional, in which case
the direction of flow will be indicated on the valve body.
2.3 MAINTENANCE PRIOR TO FLUSHING
a- If the period between installation and flushing of the of the pipeline is longer than six months a
preventative maintenance operation is suggested.
• Lubricate the stem with fluid protective oil through the stem injector (if applicable). Do not grease
lubricate seats as grease may attract debris and damage seats.
• Remove valve from line and remove any debris and reflush.
2.4 FLUSHING THE PIPELINE
Flushing washes away all welding slag, dirt, sand, solids and debris collected in the pipelines during
construction prior to turning the valve and potentially damaging the seat. Flushing where deemed
necessary is the most dangerous activity for the valve, and it happens before they are put into service.
Ball valves are normally not lubricated, however, should it be required to flush potential debris (or
lubricate sticky valves) a different practise to the lubrication of either a gate valve or plug valve should
be employed. We recommend the following: -
1. Find a good grease for natural gas or your service. The grease must be insoluble. It must be resistant to
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
Local safety regulations must be complied with for transport to the place of
installation. Make sure that the valves cannot tilt or slip in any way (see figure
below).
If the ball valve is equipped with a test connection port, make sure that it is fully
closed before pressurising the valve.

breakdown or shearing of the gel structure under high pressure injection and under the pressure
between seating surfaces. It must be stable over a wide range of temperatures, and not freeze. It must
not react chemically with the fluid and become solid, or rubber like (i.e. polymerize). Depending on the
service, the best greases are fully synthetic; if you have any doubt or concern, consult a valve
maintenance expert. Field experience has shown that greases and sealants may cause severe problems
with the seat and seal arrangement if used regularly during preventative maintenance. If a non-leaking
ball valve is lubricated with an adhesive grease/sealant, the floating, spring loaded seats can become
stuck within their seat pockets. When the ball floats due to a pressure differential across the valve, the
seals cannot track the ball and leakage can occur. Grease manufacturers produce low viscosity
synthetic ball valve lubricants such as Clare UK “601-Fluid”. Such light greases offer the following
advantages to heavier emergency sealant greases and cheaper brands of light greases:
• Enhanced resistance to hydrocarbon fluids and gases.
• Will not dry out or form a gum like some other greases when used within its application temperature
range.
• Will not disrupt the operation of the seat and seal arrangement.
Of course, be warned any type of grease, especially synthetic grease can become hard or sticky causing
torque problems and seat spring jamming in which case a line flushing agent like Clare 601 Valve Cleaner
may be required. Of course, for leaking seats a heavier sealant like Clare 601 lubricant must be used for
temporary emergency sealing.
2. Use an appropriate high pressure grease-injection pump, capable of overcoming the pipe pressure and
the high pressure build-up caused by the grease itself, during it’s injection in the grease passages.
3. Inject a generous amount of grease in the seats before flushing. The object is to cover them all and to
fill the groove between seat carrier and ball with grease. The dirt will get stuck to the grease during
flushing, but it will not come inside. And before turning the valve for the first time, inject again a small
amount of grease into the seats. A little is enough (1/4 of the normal quantity per seat, see 8.4.1). The
dirty grease will be pushed into the pipe by the fresh grease, and the turning action of the ball will
drag fresh grease towards the seats, not dirty grease.
4. Do not turn the valve during flushing.
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
Note
Do not operate the valve during flushing or entrained particulates could damage
soft seat or enter stem or seat pocket area.
Beware of greases made of synthetic oil with a mineral thickener. The natural gas
(or storage prior to use) washes away the oil, leaving the thickener behind. The
thickener is like a powder that caulks or bakes hard on the seats, increasing the
operating torque. Always wipe the seats clean as much as possible prior to
installation.

2.5 MAINTENANCE POST FLUSHING
a- At the end of flushing operation it may be possible to leave the line full of test fluid and in this case no
intervention is required. If the line must be drained proceed as follows:
• Make sure that the valve is in full open position.
• Open plugs and drain it completely. Observe safety plant procedures prior to opening any body plugs in
case any remaining fluid or gas is pressurised or trapped in body cavities.
• After draining flush the cavity of valve through the vent plug. Consult an expert on use of special
excavation procedures.
• Lubricate the stem with fluid protective oil or grease through the injector (if applicable). (Seat
lubrication is only for emergency purposes not for ongoing maintenance).
• Completely tighten all drain and vent plugs. Consult your plant safety procedures and only perform
work under supervision of expert valve maintenance personnel.
b- Operate the valve at least 2 times (complete closing and opening operation).
c- Repeat the operation every 6 months if the pipeline is not used.
d- Always get authorisation to partially operate an in-service valve.
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
Natural gas is not usually clean. Natural gas may carry condensates and dirt that
gets trapped in the valves, and may damage the internal parts. Also, operation of
the valves becomes more difficult. It is true that plant sites do install filters in their
system, but experience has proven that no system is perfect. The internal parts of
the valve can be partially protected using judicious amounts of grease to fill the
cavities. However, other than when flushing or if there is seat leakage, or if valve
cannot be opened, no grease should be applied via seat sealant injectors to soft
seats as it will attract debris and cause damage. A soft seated valve is always at
risk if service is not clean.
Personal injury may result from sudden release of any process pressure. APV
recommends the use of protective clothing, gloves and eyewear when performing
any installation or maintenance. Isolate the valve from the system and relieve
pressure prior to performing maintenance. Never unscrew sealant injection nipples
from body, seats or stem as these outlets are exposed to full line pressure and only
the in-built check valve in the sealant nipple itself isolates the pressure. Similarly,
the body drain and vent valve plugs are exposed to full line pressure if opened.
Disconnect any operating lines providing air pressure, control signals or electrical
power to actuators.

2.6 COMMISSIONING
The first year of operation is crucial, because when the pipe is put into service, all debris is pushed
downstream, and contaminates the valves along it’s travels. With time, the pipe gets cleaner and initial
problems disappear. Strainers or filters should be installed upstream of all soft seated valves.
3.0 OPERATION
The APV double block twin seal plug valve has dual expanding seals and is a plug-type which has a
mechanical means of expanding the seals when seating and retracting them prior to quarter-turn
rotation. The resilient seats (Viton, Hycar) are bonded to metal seating slips (No. 13). In opening the valve,
the centre plug (No. 12) is raised, thus retracting the seating slips through their tapered dovetail
connections. Only after the seating slips are fully retracted perpendicularly from the body seat can the
plug, which is mounted on trunnions, be rotated to the open position.
Conversely, in closing the valve, the plug and seating slips are rotated freely, with no plug-to-body
contact, until the seating slips are positioned over the ports. Then the plug is driven between the slips,
and the tapered surfaces wedge out the seating slips for a positive upstream as well as downstream
shut-off. For maximum upstream sealing, it is important to torque the valve closed.
he small APV plug valves are handwheel operated, and require up to 3 turns to open or close. Up to 2 3/4
turns expand or retract the slips, while 1/4 turn rotates the plug. Large valves operate in a similar manner
that they have enclosed weather-proof worm gearing.
The plug lift/lowering/rotation action is performed in the operator assembly. The operator handwheel is
rotated clockwise to close, and counter-clockwise to open - similar to other valves. At the top of the
valve, a position indicator flag shows the exact lug position. It appears in line with the flow when the
valve is open and perpendicular to the flow when the valve is closed. Where APV valves are used for
double block-and-bleed service, the body bleed valve may be left open when the APV valve is closed, but
must be closed before the APV valve is opened. Since APV valves do hold bubble-tight, for ease of
opening in liquid service, it is important to prevent trapped body pressure from exceeding the working
pressure of the valve. Therefore, a relief system is required to prevent pressure buildup in the body cavity.
On gear-operated models, the handwheel position may be changed as follows:
a. Place APV valve in full open position.
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
Note
Remember that plug valves are like the human body; they need ‘exercise’. Keep
moving them and lubricating them, and you will have fewer problems. Do not let
them have a sedentary life.

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
b. Remove gear housing cap screws.
c. Turn handwheel to further open the valve. This will turn gear housing assembly; continue until
handwheel comes to desired position and gear housing mounting holes are realigned.
d. Replace gear housing mounting cap screws.
3.1 PRESSURE TEST
APV plug valves can be hydrostatically pressure tested after installation, to full API6D limits per Table 1
below.
TABLE 1
ASME CLASS 150 300 600 COMMENTS
Shell Test Pressure
(Valve Open)
(psig)
(kg/cm2)
450
32
1150
81
2250
158 No leakage permitted.
Seat Test Pressure
(Valve Closed)
(psig)
(kg/cm2)
319
22
825
58
1650
116 Test upstream & downstream seats.
Supplementary
(API598) Air Seat
Test Pressure
(Valve Closed)
(psig)
(kg/cm2)
80
6
80
6
80
6
Test upstream & downstream seats. No leakage
permitted.
3.2 OPTIONAL - “DIFFERENTIAL THERMAL RELIEF” - BLEED SYSTEM
This specification addresses the proper functioning, trouble shooting, and repair of the APV plug valve
differential (pressure) thermal relief (DTR) bleed system.
Background
When APV valve is seated and completely fill with a liquid, any slight variation in temperature due to the
sun’s rays or ambient thermal fluctuations will cause drastic changes in body cavity pressure resulting
from thermal expansion.
While results vary under actual service conditions depending on media, pressure vessel rigidity, and
presence of entrapped gas it is known that dangerously high pressures will build up in liquid filled
positive shutoff valves. Therefore, the APV in liquid service requires a pressure relief device.
The differential (pressure) thermal relief system is one such automatic “device” and
should be included on every automated valve.
The differential (pressure) thermal relief system is arranged as shown below. A
variety of components are used. The relief valve mounted in the centre of the valve
body pipes over pressure to the upstream throat of the valve.
The standard relief valve is set to open at 25 PSI on all valves regardless of working
pressure. With the valve closed, the relief valve will open at 25 PIS above upstream
pressure. This system functions only when the valve is closed.

A manual body bleed valve is included on the APV as standard. This bleed valve
installed in the relief system is opened after the APV valve is closed. Seal
effectiveness can be immediately evaluated, after allowing a few seconds for
stabilisation of cavity volume due to entrained air or gas. The bleed valve must be
closed before the APV valve is opened.
An isolation valve installed in the upstream throat tap is also included. It must be left
open to permit relief system to relieve pressure upstream. The isolation valve will be
used only for maintenance and troubleshooting which will be explained later. Valve
is to be CLOSED ON FOR REPAIR. If closed during normal operation the automatic
portion of the relief system (relief/check valve) will be defeated. (The outlet of the
relief valve would close when closing the isolation valve).
Valve Operation
In the fully open position, the resilient seals are positioned out of the flow
path and protected within the body of the valve itself.
As the valve is cycled from the fully open to closed position, the plug
begins a 90 degree rotation. During the entire rotation of the plug the
resilient seals located on both slips are retracted away from the body.
This ensures that there is no rubbing or scraping action on these resilient
seals during rotation of the plug from the open to the closed position.
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
4.0 REMOVAL FROM LINE
It is desirable that the maintenance operations are carried out by skilled personnel who are experienced
and well trained in standard field techniques and procedures. Be sure that the personnel involved in such
operations are aware of fundamental safety rules indispensable for the protection of their own and other
people’s safety.
If it is required to remove the valve from the line proceed as follows:
a- Ensure the line is fully depressurised.
b- Partially open the ball in order to depressurise the valve.
c- Remove the drain plug and vent plug. First release vent to ensure no remaining pressurised gas or fluid
trapped in cavity. Take safety precautions to avoid personal injury during this procedure. Then carefully
remove drain plug once you are sure valve has no remaining fluid or gas in cavity.
d- Keep the plug in the fully open position.
e- Remove the valve from the line. The valve shall be handled by means of lifting lugs fitting on the valve
(if applicable). Standard field techniques and procedures are satisfactory to disconnect it from the line.
f- After removal of the valve from the line, clean the valve and seal the ends with plastic or wooden
covers.
5.0 GEARBOX REMOVAL
a- Removal (refer to enclosed drawings)
• Unscrew the bolts/nuts.
• Lift the gear box to disengage the valve stem and remove it with the plate.
b- Put in position a removable cover to prevent the introduction of dust, sand, etc., in the actuator
bushing.
Steam seal body leakage can result in personal injury.
Note
The actuator or gearbox position stops have been properly set in the shop. Do not
alter the setting.

2
4
6
6
7
7
8
3
12
9
9
10
10
14
14
5
13
11
15
11
16
1
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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
6.0 VALVE DISASSEMBLY
The following should only be performed by an APV approved reconditioner.
Note, The below parts refer to the general drawing in Table 2. This is a general overview drawing only.
Each size & class range does vary so refer to the actual as-built drawing.
TABLE 2 - APV PLUG VALVE ASSEMBLY - TYPICAL
NO. DESCRIPTION
1 Hex Head Bolt
2 Packing Gland
3 O-Ring
4 O-Ring
5 Packing
6 Hex Nut
7 Stud
8 Upper Bonnet
9 Bushing
10 O-Ring
11 Gasket
12 Plug
13 Slip
14 NPT Plug
15 Body
16 Lower Bonnet
Sample only - refer to as built drawing as
design varies according to size, class & model
variation.

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EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES
7.0 MAINTENANCE
In cold climates before freezing weather sets in, any possible collection of water below plug or plug
trunnion should be drained out through drain plugs (No. 14) Check manual body bleed (no. 23) for zero
pressure before removing plugs.
If, at any time, the manual body bleed should indicate an upstream leak which cannot be stopped by
ordinary hand force on the handwheel, this must be corrected by one of the following:
a. Operate valve through open - close cycle while fluid is flowing, to try flush out valve body. After
several flushing attempts, close valve and check body bleed again. If body bleed still indicates valve
leak, check thermal relief assembly before replacing seating slips.
b. To replace seating slips, the line must be drained. Place valve in open position (check body bleed for
zero line pressure); then remove lower plate (No. 16) or bonnet (No. 8. APV has both top and bottom
entry to facilitate in-line maintenance.
c. Seating slips (No. 13) can be withdrawn from plug dovetails and replaced. It is usually best to replace
the gasket (No. 11) and lower plate o-ring (No. 10) or bonnet “O” ring (No. 10) when slips are replaced.
If stem packing should fail, it can be changed as follows:
a. Close valve and check body bleed for upstream shut off. Leave body bleed open. If valve is holding
tight, then packing can be changed under line pressure. If body bleed shows the valve is not holding
upstream, then the line must be bled down in order to proceed with the change.
b. Remove operator as outlined below.
c. Remove packing gland (No. 5) and replace inner and outer o-rings (Nos. 3 & 4).
d. Remove packing rings (No. 5) carefully and replace.
e. Replace operator as outlined below.
Use extreme caution when venting the body cavity of a pressurised valve.
If the body cavity keeps venting fluid at a constant flow rate for a very long time,
it is a signal of bad sealing of the valve seats. For liquid service only a lower drain
valve will immediately indicate a leak.