Flowserve Double-Disc Gate Valve User Manual
USER INSTRUCTIONS
Anchor/Darling Double-Disc Gate Valves
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2
/2 and over with T-head stem
FCD ADENIM0003-01 - 07/14
Installation
Operation
Maintenance
Experience In Motion
Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
Contents
1.0 Valve Description 4
1.1 Recommended Uses 4
1.2 Principles Of Operation 4
1.3 Design Features 4
1.3.1 Bonnet Seals 5
1.3.2 Disc Assembly And Seats 5
1.3.3 Actuation 5
2.0 Care Of Valve Prior To Installation 7
2.1 Receiving Inspection 7
2.2 Handling 7
2.3 Storage 7
3.0 Installation Instructions 7
3.1 Rigging 7
3.2 Cleaning 7
3.3 Installing Valve In Line 7
4.0 Operating The Valve 8
4.1 Hand Actuated 8
4.2 Motor Actuated 8
4.3 Operating Tips 8
5.0 Valve Maintenance 9
5.1 Inspection 9
5.2 Lubrication 9
5.3 Cleaning 9
5.4 Packing 9
5.5 Bolting Torque Values 10
5.6 Refinishing Sealing Surfaces 16
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Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
6.0 Disassembly 16
6.1 Actuators 16
6.1.1 Handwheel 18
6.1.2 Gear 18
6.1.3 Electric Motor 18
6.2 Bonnet Removal - Flanged Joint 18
6.3 Bonnet Removal - Pressure Seal Joint 20
6.4 Disc and Stem Assembly 23
7.0 Inspection and Maintenance 23
7.1 Discs 23
7.2 Wedges 24
7.3 Stem 24
7.4 Body 24
7.5 Bonnet 25
7.6 Stem Nut and Yoke Sleeve 25
7.7 Actuators 25
7.8 Bolting 25
7.9 Gland, Lantern Ring, Gland Spacers 25
8.0 Assembly 25
8.1 Disc - Stem Assembly 25
8.2 Bonnet - Flanged Joint 26
8.3 Bonnet - Pressure Seal Joint 26
8.4 Actuators 27
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Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
1.0 Valve Description
1.1 Recommended uses
Anchor/Darling Double Disc gate valves are designed to provide
isolation of a piping system or a component when closed. They are not
suitable for modulation of flow; i.e., throttling, and should not be used
for that purpose.
1.2 Principles of operation
The principle parts of a double disc valve are the body, bonnet, disc
assembly, stem and top works (Fig. 1). The body and bonnet contain
the fluid within the system. The disc assembly is positioned by the
stem to either block flow through the body or is raised to leave an
unobstructed flow passage.
The disc to seat seal in the double disc gate valve is created by a
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combination of internal pressure and mechanical wedging force. When
the line pressure is high, the differential between the upstream and
downstream ports forces the downstream disc against the downstream
seat and creates a seal. At lower line pressures (under approximately
Figure 1
100 psi), the pressure force alone may not be sufficient to create a seal.
A mechanical force resulting from the discs being expanded against
the seat rings by wedging mechanism between them provides the
additional force necessary to seal.
1.3 Design features
1.3.1 Bonnet Seals: Anchor/Darling Double Disc Gate valves are
supplied with two basic types of body-bonnet closures; bolted
bonnet or pressure seal.
The bolted bonnet closure (Fig. 2) is a bolted flange tongue
and groove joint with spiral-wound stainless steel gasket with
graphite filler. The seal depends on the bolt preload to maintain
sufficient compressive force on the gasket.
Pressure seal type closures (Figs. 3 & 4) utilize a tapered soft
metal or graphite gasket for sealing. The gasket is contained
within the body neck bore by a retaining ring. The tapered inner
surface of the gasket bears against a mating annular surface on
the valve bonnet. Under internal pressure, the bonnet is forced
against the pressure seal gasket, wedging it against the body
neck wall. A slight interference angle produces a line contact
Figure 2
Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
Figure 3
Figure 4
and high sealing pressure. The greater the valve pressure the
tighter the seal. No bolting force is required to maintain the
seal although the bonnet is initially drawn into contact with the
pressure seal by cap screws.
1.3.2 Disc Assembly: The Anchor/Darling Double Disc assembly
(Fig. 5) consists of dual floating discs with a two piece wedging
mechanism between them. Trunnion on the back of each disc
fit into holes in the upper wedge. The upper wedge in turn is
connected to the stem, which allows it to serve as a carrier
for the discs. A lower wedge is loosely hung on a land on the
upper wedge between the discs.
As the disc assembly is lowered into the seat (Fig. 6), the lower
wedge contacts a bridge in the bottom of the body between the
seats. Further travel of the upper wedge (Fig. 7) causes it to
contact the lower wedge on the beveled interface and spread
both the wedges and the discs out against the seats.
When the stem is raised, the upper wedge immediately pulls
away from the lower wedge, eliminating the force of the discs
on the seat.
Body seat rings are set into machined recesses in the body
which support and retain the rings (Fig. 8). A seal weld is
provided between the body and the rings. This weld is for
sealing only and is not structural. The seat rings are replaceable.
1.3.3 Valve Actuation (Topworks)
A gate valve is actuated by moving the disc assembly in and out of
the seats with the stem. The necessary thrust for opening or closing
is imparted to the stem by the valve actuator which is supported
and restrained by the yoke structure. Five (5) types of actuators are
normally supplied; handwheel, manual gear, electric motor, pneumatic
cylinder and hydraulic cylinder. The first three impart rotary motion to a
stem nut which converts the rotary motion to linear stem movement via
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Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
Figure 5
Figure 6
Figure 8Figure 7
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Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
the acme stem threads. The pneumatic and hydraulic cylinder actuators
provide direct linear motion to the stem. Always consult the maintenance manual for the specific actuator or actuator accessory before
using or performing maintenance on these components.
Sealing of the bonnet-stem penetration is accomplished by a bolted
gland stuffing box containing ring type packing. An emergency back up
seal is provided in the form of a backseat rigidly mounted in the bonnet.
2.0 Care of Valve Prior to
Installation
2.1 Receiving inspection
Upon receipt of the valve, thoroughly inspect it for shipping damage.
As a minimum, the following items should be checked:
1. Handwheel and shaft - check for bending or impact damage.
2. Switches and actuating mechanisms - bent or broken parts?
3. Missing or loose bolting?
removed for storage elsewhere, reseal the valve end covers to protect
the internal cleanliness of the valve.
Motor actuated valves, if stored for more than a few months require
special care of the actuator. Motor and switch compartment heaters, if
supplied, should be connected. The major concern is condensation on
the internal parts of the actuator. For this reason, rapid and/or extreme
temperature and humidity changes should be avoided. Storage in a
temperature and humidity controlled environment is desirable. Long
term storage of motor actuators may affect the terms of the warrantee
and the manufacturer should be contacted for specific information.
3.0 Installation Instructions
3.1 Rigging
When lifting the valve for installation in the line, it is important that
slings of adequate size be used. The capacity of the sling must
exceed the weight of the valve. Slings should pass under the valve
body and through the yoke arms. Block carefully to prevent damage
or abrasion of component parts and finishes.
4. End covers in place?
5. Is valve securely fastened to shipping skid?
6. Are spare parts shipped with valve in place and secure?
2.2 Handling
The valves are shipped strapped to wooden skids designed to be
moved by forklift. It is recommended that when being handled prior
to installation, the valve be kept on its skids and a forklift truck be used
for moving. If an overhead crane is used, care must be exercised to
center the load. The slings should not lift the valve by the wooden skid
structure alone, but must pass under the valve.
2.3 Storage
Store valves on their shipping skids in a clean dry area protected from
the weather.
Valves are generally shipped without the permanent packing installed.
Experience indicates that stem corrosion pitting can result when
valves are stored with the packing in place. For this reason we do not
recommend installing the packing until valve is to be put in service.
The service packing is shipped with the valve, contained in a plastic
bag placed in the valve port or attached to the yoke. If the packing is
3.2 Cleaning
Prior to installation remove the valve end covers and inspect for
cleanliness. If any sign of foreign matter is observed in the valve
internals, open the valve and place it on its side (stem horizontal) and
flush thoroughly with water. Steam or air may be used if water is not
available but exercise caution that the high velocity does not drive
debris into clearance spaces.
3.3 Installing valve in line
3.3.1 The pipe must be properly supported and aligned with the valve.
Seat leakage in valves is frequently caused by seat misalignment resulting from excessive end movements introduced in
the cold springing of the connecting pipe.
3.3.2 Before weld end valves are welded into the line, raise the disc
assembly off the seat a sufficient distance to prevent arcing.
3.3.3 The preferred installation of double disc gate valves is with the
lower wedge on the downstream side. The only exception is
that when in a vertical pipe with flow down, the lower wedge
should be on the upstream side. Although standard convention
at Flowserve locates the lower wedge on the right hand side of
the valve when facing the nameplate, it is recommended the
assembly drawing be checked to verify orientation.
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Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
3.3.4 It is recommended that the valve be installed with the stem
vertical, when possible. This orientation provides enhanced
packing life and simplifies disassembly/reassembly.
3.3.5 Following installation of the valve in the line, install the packing
supplied with the valve. (See maintenance Section 5.4 for
specific instructions). This operation may be performed
following valve cleaning if more convenient.
3.3.6 Before the valve is placed in operation, check all bolting for
tightness and lubrication per section 5.5.
4.0 Operating The Valve
4.2.2 Adjustments of torque or limit switches should not be
attempted without first consulting Service Engineers. Failure
to obtain proper authorization when resetting torque or limit
switches may void the warranty.
Under no circumstances should the torque and/or limit switches
be completely bypassed.
They are included to provide protection of the valve internals.
Removal of their protection can cause extensive damage to the
equipment.
4.2.3 The valve is normally supplied with the torque switch wired
to stop the actuator in the closed position and the limit switch
wired to stop in the full open position. Using the torque switch
to control travel in the opening direction may damage the
backseat. The valve should be backseated only by using the
handwheel.
Prior to operating the valve for the first time, verify that the valve
has been prepared in accordance with the preceding sections of this
manual.
4.1 Hand actuated
Handwheel actuated valves close on clockwise rotation of the wheel and
open counter-clockwise. This is true also for the handwheel on gear
and motor actuators.
4.1.1 Flowserve valves, if properly set up and maintained, will close
with ordinary effort on the handwheel. The required total force
at the rim of the handwheel should not exceed 100 lbs. and will
usually be much less. If tight shut-off is not achieved do not
use “cheaters” or other means of extra leverage. Instead, open
and close the valve once in an attempt to dislodge any foreign
matter on the sealing area that may be interfering with closure.
If this fails, disassemble the valve and inspect the internals for
galling or other damage.
4.1.2 The impactor feature on valves supplied with impactor
handwheels is intended to be used only in unseating the disc. If
the impactor is used to seat the disc it may be difficult to reopen
the valve.
4.2.4 When powering the actuator for the first time, observe that the
direction of rotation is correct. If not, the power leads must be
reversed.
4.2.5 Manual operation may be performed at any time by pulling the
declutch lever downward.
The lever will stay in the manual mode until the electric motor is
actuated whereupon it will automatically disengage.
4.3 Operating tips
Do:
• Operate valves at least every 6 months.
• Keep stem clean and lubricated.
• Inspect valves regularly.
• Lap seats promptly if valve leaks.
• Use normal torque on handwheel.
• Check packing regularly.
Do Not:
• Over tighten packing.
4.2 Motor actuated
4.2.1 The motor actuators are adjusted for correct operation when
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shipped from the plant. It should not be necessary to re-adjust
the torque and limit switches when the valve is placed in
operation unless the actuator has been removed from the valve
or the switch adjustments have been tampered with.
• Torque-out motor operator against backseat.
• Keep valve backseated during normal operation.
• Keep gate valve in a partially open position for any
length of time or use for throttling.
• Bypass or reset torque or limit switches.
Anchor/Darling Double Disc Type Gate Valves FCD ADENIM0003-01 - 07/14
• Use unauthorized actuator assists such as – pipe
wrenches – cheaters.
• Bring valve to fully backseated position immediately
upon opening a valve in a hot system. Allow 15
minutes for stem to cool before backseating valve.
5.0 VALVE MAINTENANCE
Double Disc Gate valves are designed to be essentially maintenance free
pieces of equipment. When used in the proper application and operated
correctly, they will provide reliable operation for many years. The only
area that is expected to require regular attention is the adjustment
and (if necessary) replacement of the stem packing. The frequency
of this operation will be dependent on the service conditions, the type
of packing used and the care with which it is installed. Some other
maintenance recommendations are included in the following sections
for information.
5.1 Inspection
• Motor Actuator
• Yoke Clamp
• Mounting of accessories, (i.e. limit
switches)
5.2 Lubrication
1. Stem: Keep stem threads lubricated with a light coating of grease
such as Dow Corning Molykote P37 paste, Mobil grease 28 or MOV
Long Life.
2. Yoke Sleeve: Lubricate with general purpose grease every six
months. Apply with grease gun to grease fitting.
3. Air cylinder operated valves require only a light coating of grease or
oil on the Cylinder Rod.
4. Motor Actuator: Every six months lubricate drive sleeve top bearing,
using grease gun on pressure fitting in housing cover. See Motor
Actuator Manual for further information.
5. Bolting: Lubricate with Nuclear Grade Never Seeze or equal.
The most important aspect of valve maintenance is periodic inspection.
The early detection of a malfunction can, in many cases, prevent a
minor defect from becoming a major problem. It is very important that
leakage from any of the major seals (packing, disc/seat, body-bonnet)
be addressed immediately. The smallest weepage can quickly become
a major problem if it is not treated promptly. Some other areas that
should be included in a periodic inspection program are:
1. Lubrication:
• Stem
• Yoke Sleeve
• Motor Actuator Drive Sleeve
• Pneumatic Actuator Sliding Surfaces
2. Cleaning:
• Stem
• Packing Area
• Pressure Seal Area
• Body Bonnet Studs
3. Bolting:
• Body-Bonnet
• Bonnet Yoke
5.3 Cleaning
The frequency and extent of cleaning will depend on the valves’ location
and service conditions. It is important that the stem and packing gland
parts be kept clean and free of foreign material. Do not allow water
or dirt to collect in the body neck bore area above the pressure seal of
pressure seal valves. The build up of corrosion or extraneous material
may interfere with removal of the bonnet. For the same reason,
excessive rust should not be allowed to build-up on the body-bonnet
bolting of bolted bonnet valves.
5.4 Packing
6. Most Flowserve valves are supplied with graphite packing
supported by braided graphite end rings. Other packing materials
are furnished when specified.
7. Remove nuts from gland bolts and raise the gland flange and
gland. These two parts may be held out of the way with wire.
8. Clean the threads and insure the nuts thread on easily. Any
binding or sticking must be eliminated as this will adversely affect
torque values.
9. Remove the old packing with a packing hook. The lantern ring in
double packed valves must also be removed to expose the lower
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