MASCOT DiskFlo Guide

CAUTION :
1. Use pressure relief valves for high pressure
piping.
2. Use explosion proof valves/accessories for
dangerous media piping.
3. Use fire safe valves for piping where chances of
fire by external means.
4. Use seismic proof valves where chances of
earthquake are frequent.
5. Check whether locaon of the valve mounng is
of the same service/applicaon as specified on
the marking plate.
Installation, Operation,
Maintenance Instructions
DiskFlo
Control Valves

2
GENERAL INFORMATION
The guidelines below will help you in un-packing, installing and
doing maintenance of DiskFlo rotary valves. It is advised that the
relevant personnel should review this bulletin thoroughly before
proceeding to install, operate, or perform maintenance on the
DiskFlo rotary valves. Instructions for maintenance of
accessories, fail-safe systems, etc. are given separately.
Installing, maintaining, troubleshooting, calibrating, and
operating Mascot actuators or positioners is not covered in this
publication. You need to refer the right Mascot Installation,
Operation, Maintenance guidelines when the information is
needed.
It is strongly advised to stick to the WARNING and CAUTION
notes for preventing any possible injury or damage to personnel
or valve parts. Modifying, substituting nonfactory parts, or using
maintenance procedures other than mentioned in this manual
not only will adversely affect performance and can be dangerous
to the operators and equipment but also will void the warranties.
WARNING : Please follow the standard industry safety practices
when working on every process control product. Use of personal
protection and proper lifting is advised.
Note : The onus of selecting the right fastener material is on the
customer. The supplier cannot know about the valve service
conditions or environment that may be existing. The standard
body bolting material of Mascot's is B7/2H. There is an option
for B8 (stainless steel) when temperatures are above 800 °F and
with alloy body or stainless steel valves. The onus of considering
material's re-sistance to stress corrosion cracking in addition to
general corrosion lies on the customer. Periodic inspection and
maintenance is required, as with all the mechanical equipments.
In case more details are needed about fastener materials, please
contact the local Mascot factory, office or representative.
Unpacking :
During the unpacking of valve, the packing list received with
the materials needs to be checked. Detailed description of the
valve and accessories are included in the lists in each
shipping container.
Proper attention is to be paid during the positioning of lifting
straps. This will avoid damage to tubing and mounted
accessories while lifting the valve from the shipping container.
The actuator lifting ring is advised to be used for lifting
Valves up through 14-inch. Use lifting straps or hook through
the yoke legs and outer end of the body for lifting the larger
valves.
The shipper should be contacted immediately in case of an
unfortunate event of damage caused due to negligence while
shipping.
Mascot representative is always at your service in case any
problems.
Installation :
The first step is to do basic cleaning for the line of dirt, scale, welding
chips, and other possible foreign material. The surfaces of gasket
should be cleaned thoroughly thus ensuring that the joints are leak-
proof
The direction of the flow should be checked for ensuring that the
installation of valve is right. In case of Fail-closed valves,installation
should be done only on gas service with the shaft upstream. In case
of liquid service valves, installation is preferred with the shaft
downstream, irrespective of the air failure action. Under certain flow
conditions, however, the valve can flow shaft upstream. In case of
Fail-open valves, installation should be done with the shaft
down-stream.If the mounting of valve must be with the shaft upstream
in liquid service,
please consult our representative or contact our factory.
WARNING : It has to be made sure that the flange face gasket
covers the seat retainer and body and surface when installing the
valve in line between flanges. There is a possibility of excessive
leakage downstream in case this is not done. Figure 1 can be
referred to for "Seat Insert/Snap-ring Configuration"
Before and during the installation process, the valve needs to
be fully closed.
WARNING : Keeping clothing and body parts away from the
rotating disc and the seat when operating the valve can avoid any
possible serious injuries.
CAUTION : DiskFlo has a self-centering seat and therefore the
valve should not be opened at any time during installation
process, keeping it closed until the complete installation of the
valve.
Air supply and instrument signal needs to be connected. Valve
positioners are usually present in Throttling valves. Separate two
connections are given for instrument signal and air supply. 150
psi air supply is suited for both cylinder and positioner. No need
for an air regulator is there till the supply pressure is 150 psi.
Unless the supply air is unusually clean and dry, an air filter is
recommended. There should be no leaks in connections.
CAUTION : For valves with air filters, the air filter will not
perform properly if the air filter bowl is not pointing down.
NOTE : There are certain cases wherein the air supply needs to
limited to 100 psi rather than 150 psi. The sticker pasted near the
upper air port on the cylinder indicates the same. An air regulator
must be installed to Ensure that the supply pressure is not exceeding
the desired 100 psi.
For proper disc rotation, it is necessary to have proper clearance
internally in the mating piping.
For proper sealing, the torque values as recommended should be
applied to line flange bolting for proper sealing - Refer Table 1
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
Table 1 : Flange Bolting Torques
 Valve Rating Torques
 Size (In.)  (ft.Lbs.)
  150 118
 2 300 118
  600 118
  150 118
 3 300 209
  600 209
  150 118
 4 300 209
  600 505
  150 209
 6 300 209
  600 505
  150 209
 8 300 337
  600 728
 10 150 337
  300 728
 12 150 337
  300 728
 14 150 505
 16 150 505
 18 150 728
 20 150 728
 24 150 1009
 30 150 1009
DiskFlo Control Valves

DiskFlo Control Valves
3
Quick Check:
Before starting, the control valve should be checked as per the
these steps given below :
Full stroke needs to be checked by making the appropriate
instrument signal change. The disc position indicator plate
mounted which is mounted on the transfer case should be
observed for this. The change in the position of the disc must
be in a rotary fashion and smooth.
All the air connections should be checked for leaks and in
case of leaking lines, tighten or replace.
The packing nuts are to be tightened evenly by little over
finger-tight force.
CAUTION : The packing should not be over tightened. The
over tightening may cause excessive packing wear and
high shaft friction, that can adversely affect the rotation of
the shaft.
The packing nuts need to be inspected after some time of
operation of the valve to make sure that they are just over
finger-tight and not more. Readjustment should be done if
needed. The packing nuts should be tightened just enough to
stop leakage in case of the leaking in the packing box.
For observing the valve failure mode when air failure occurs,
the valve needs to be positioned to mid-stroke and the air
supply needs to be shut off or the instrument signal needs to
be disconnected. On observation of the indicator plate, the
disc should either fail open or closed. Please refer "Reversing
the Actuator" section in the appropriate Actuator Maintenance
Instructions if incorrect.
PREVENTIVE MAINTENANCE
The preventive maintenance steps presented below need to be
followed and at least once every six months, proper operation
should be checked. These steps are easy and can be performed
while the valve is in line and, in some cases, without interrupting
service. Refer to the "Dis-assembly and Reassembly" section if an
internal problem is suspected.
Check for any signs of gasket leakage through body and line
flanges. Tightening of flange bolting should be done if
needed.
Pay attention to any corrosive fumes or process drippings that
are likely to cause damage to the valve.
For any areas of severe oxidation, cleaning of the valve needs
to be done, followed by painting.
For proper tightness, inspect the packing box bolting. The
tightness of the Packing nuts should be slightly over finger-
tight. To prevent stem leakage, tighten as necessary.
CAUTION : Never overtighten the packing.
In case of valve supplied with a lubricator, lubricant supply
needs to be checked and adding of lubricant if necessary
should be done.
When possible, stroke valve and verify functioning for
smooth, full-stroke operation by seeing the disc position
indicator plate that is on the transfer case. An internal valve
problem is indicated by unsteady movement of the disc (In
case when Grafoil packing is used, jerky motion is normal).
By observing the gauges and the disc position indicator plate,
check the positioner calibration. Ensuring calibration of the
positioner to the correct range is important.
Ensure that the positioner linkage and internal actuator parts
are securely fastened by removing transfer case cover plate.
Using a soap solution, check for air leaks through actuator
stem seal.
CAUTION : Without the cover plate installed, air should
not be applied to the actuator because there is a possibility
of the unsup-ported shaft getting damaged.
Ensure secure fastening of all accessories, brackets and
bolting.
For correct fail-safe action, remove air supply and observe
stroke plate if possible.
To check for air leaks through the O-rings, spray soap
solution around the cylinder retaining ring and the adjusting
screw.
The ex-posed portion of the shaft should be free from dirt or
other foreign material.
In the air filter, check and replace cartridge if needed.
DISASSEMBLY AND REASSEMBLY
Removal of Valve from Line
When disassembly is required on a suspected internal
problem with the valve, the valve needs to be removed from
the line. The procedure for the same is as follows:
WARNING : Bring the line to atmospheric pres-sure and
drain all process fluids. In case of presence of caustic or
hazardous materials, decontaminate the valve. Possibility
of injur is eliminated by decontamination.
1.
2.
3.
4.
1.
2.
3.
4.
5.
7.
6.
8.
9.
10.
11.
12.
13.
Figure 1: Seat Retainer Configurations
A Dual Seat B Metal Seat C Soft Seat D Seat Insert /
Snap-ring

DiskFlo Control Valves
4
Ensure complete closure of the valve.
Note : For valves with fail-open action, supply air pressure
under the actuator piston for closing the valve. The handwheel
can be used to close the valve, in case provided.
The valve needs to be supported for which, attach a hoist or
by some suitable means.
The line bolting should be removed. Pushing or pulling on
valve actuator should not be attempted to pry line flanges
apart.
The valve needs to be Slided carefully from the line. The valve
should not be twisted as this might cause damage to gasket
surfaces.
On complete removal of the valve from the line, the air
pressure from the actuator should be slowly relieved.
Removing Actuator From Body
With the actuator removed from the body, it is easy to dissemble
the body assembly and the actuator.The procedure for the same
is as follows To do so, proceed as follows:
Before disconnecting the actuator, from the body assembly,
support the actuator assembly by the lifting ring.
The transfer case cover bolts need to be removed. With care,
pry or slide the cover plate from the end of the shaft.
Loosen the linkage bolt on Mascot actuators.
To release spring pressure, loosen the actuator adjusting
screw.
The bolts connecting yoke to the actuator subassembly need
to be removed.
The entire actuator assembly needs to be slide off the shaft.
To loosen it from the shaft splines, it might be necessary to
wedge the halves of splined lever arm apart.
Disassembling the Body
Refer to Figures 1, 2 and 5 to disassemble the body and
proceed as instructed below :
For DiskFlo valves with seat retainer screws, the seat retainer
screws and retainer clips need to be removed. The seat
retainer needs to be lifted out of the valve body. (Presented in
Figures 1A, B, C).
For valves supplied with retainer snap-ring configu-ration,
insert a screwdriver carefully in the key slot provided in the
retainer; pry the retainer and snap ring out of the valve body.
(Presented in Figure 1D).
Remove both packing nuts to remove the gland flange. The
studs need not be removed.
By tapping on the small end of the pins using a punch and
hammer, drive the taper pins out of the disc.
Remove the end plug (optional bolted flange and seal if
applicable).
By inserting a press or a nylon rod (or identical material) into
body's blind end, and using a hammer, carefully tap the shaft
through the body and remove.
CAUTION : Utmost care should be taken during disassembly so
that the splined end of the shaft is not damaged.
Supports underneath the disc are needed to avoid scratching
the sealing surface of the disc while removing the shaft. As
the shaft comes off the bearing surfaces, the binding of shaft
in the body is prevented.
Using a dowel of appropriate diameter, push the packing and
bearings out of the body. Packing needs to be pushed from
the center of the valve.
Reassembling the Body
To reassemble the body sub-assembly, refer Figures 1, 2, 3, and
5 and proceed as mentioned below :
All parts should be cleaned.
The disc seating surface should be checked to make sure it is
smooth and free of scratches and scoring.
CAUTION : Damaged discs should be promptly replaced as
damaged or dirty seat surfaces can cause excessive seat wear and
high torque requirements.
Figure 2: Body Assembly
Note : Item numbers correspond to bill of material of Valve. Please refer to it for specific part numbers.
(Item No. 123)
Seat Retainer ClipSeat Retainer Bolt (Item No. 124)
Body
(Item No. 1)
Taper Pins (Item No. 52)
Shaft Bearing (Item No. 83)
Shaft (Item No. 51)
Inner Packing (Item No. 88)
Outer Packing (Item No. 88)
Packing Follower (Item No. 87)
Packing Spacer(s) (Item No. 93 - 95)
Packing Retainer (Item No. 85)
Shaft
Plug
(Item No. 122)
Disc
(Item No. 50)
O-ring
(Item No. 61)
Seat
Shaft
Bearing
(Item No. 83)
Disc Stop
1. 1.
2.
3.
4.
5.
6.
7.
1.
2.
2.
3.
4.
5.
1.
2.
3.
4.
5.
6.

DiskFlo Control Valves
5
Shaft needs to be inspected for galled surfaces or scratches.
The very smooth finish of the DiskFlo shafts give maximum
performance. In case of any damage, replace the shaft or
contact our factory representative.
NOTE : In recent designs, Disc and shaft are interchangeable.
Replacing the disc does not require replacing the shaft. Older
designs needed that the disc and shaft be machined together.
For matched disc and shaft, contact the factory.
New sliding stem shaft bearings should be inserted into the
body. (With some designs, a press may be required.)
NOTE : Previous DiskFlo designs need the disc to be aligned
in the body in such a way that it can properly rotate. After
aligning the shaft bearings on either side of the disc, insert the
shaft through the body, disc and bearings.
Making sure it will rotate in the proper direction with respect
to the body's internal disc stop, position the disc in the body.
insert the shaft through the body, disc and bearings.
CAUTION : To avoid damage to both the shaft and
bearings, care needs to be taken while sliding the shaft
into the sliding stem shaft bearings.
New taper pins need to be inserted and driven firmly into
place in the side opposite the stop.
Over splined end of the shaft and into the body, slide the
packing retainer, lower packing, packing spacer, upper
packing, and packing follower. The typical packing
configurations are as in Figure 3.
NOTE : Whenever rebuilding the packing box, use new
packing.
CAUTION : As the sealing on V-ring packing is at the
feather edge, it is necessary to avoid damage to that edge.
Install the end plug again (alternatively replace the end seal
and again install the bolted flange).
The gland flange and packing nuts should be Reinstalled.
Packing to be tightened evenly to slightly over finger-tight
strength.
CAUTION : Over tightening of packing should be avoided. This
causes excessive packing wear and high shaft friction, which may
hamper rotation of the shaft.
NOTE : Orientation 1 is standard. Orientation positions 2 and 4 are
not available in some actuator sizes. Contact factory.
A gasket is required in all seat configurations with screw/clip
retainers (item #55) installed in the appropriate groove. This
is done by pressing the gasket into the appropriate groove.
In case the seat retainer is the screw/clip type and possesses
a soft or dual seat, press the soft seat into the soft seat
retainer or metal seat. (An interference between the soft seat
and the retainer is necessary.) Secure the retainer or metal
seat in place by tightening the retainer clips and screws, with
the valve in the closed position. This helps the seat to align
with the disc, making tight shutoff possible.
In case the seat retainer is the screw/clip type with a metal
seat design, a gasket needs to be installed in the metal seat
before clipping the seat in place with the screws and seat
clips.
NOTE : DiskFlo valves of earlier design may require the disc to be
open while installing the soft seat into the body.
In case an early design DiskFlo seat retainer has an indexing
groove to accept a soft seat, press the corresponding seat
into the retainer groove. Install the seat retainer subassembly
into the body.
For valves supplied with the retainer snapring configuration,
the snapring needs to be installed into the groove around the
retainer (or metal seat). With the open ends of the snap-ring
in the body groove, start the retainer into the body. Lightly
press the snap-ring into the retainer until both the retainer
and snap-ring slide into the body.
For early design DiskFlo valves supplied with seat retainer
screws, the insert and retainer need to be installed into the
body with the disc open. The retainer screws need to be
loosely installed, then the disc is to be closed. After the closed
disc has centered the seat, tighten the screws. This permits a
tight shutoff as it allows the seat to align with the disc.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Figure 3: Typical Packing Configurations
SafeGuard / SureGuard
Fire-safe Option
(live-loading omitted)
SureGuard
Standard Square Standard Single "V" Twin "V"
SafeGuard
(packing studs rotated 45 degrees)
Twin "V" with Lubricator

DiskFlo Control Valves
6
Remounting Actuator to Valve
It needs to be verified that the disc rotation matches the actuator
rotation and complies with the air failure requirements, before
mounting a Valflo actuator on the valve body.
For mounting the actuator, the procedure is as follows:
The entire actuator assembly needs to Slide onto the shaft. If
needed on Valflo actuator designs wedge the splined lever
arm apart to loosen it on the shaft splines. Marks provided on
the end of the shaft and on the lever arm should be aligned
for full rotation of the disc.
The actuator yoke needs to be bolted to the valve body.
Ensure that the stroke indicator plate is positioned properly
for accurately indicating the rotation of the valve.
Align the actuator lever arm on the shaft so the actuator stem
is centered in the transfer case. The linkage bolt needs to be
firmly tightened.
CAUTION : Applying air to the actuator without the cover
plate installed; may cause damage to the unsupported
shaft.
Until the disc is parallel to the seat surface, but not resting on
body disk stop, adjust the actuator stroke stop bolts.
CAUTION : To prevent the valve disc from overstroking,
the actuator stroke stop bolts must be properly adjusted.
The valve shaft may be twisted or sheared off if incorrectly
adjusted.
The valve in line needs to be installed as mentioned in
"Installation" section.
1.
2.
3.
4.
5.
Style E
Air-to-close
Fail- open
Air-to-close
Fail- open
Air-to-open
Fail-close
Air-to-open
Fail-close
Shaft Downstream
Style F
Shaft Downstream
Style G
Shaft Downstream
Style H
Shaft Upstream
NOTE: Styles F and H may
require a heavy-duty spring
to achieve failure.
Right-hand Mounting
Facing Downstream
Left-hand Mounting
Facing Downstream
FLOW
O
SS
O
SS
O
SS
O
SS
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4
Style G Style H Style F Style E
Left-hand
Mounting
Right-hand
Mounting
NOTE: Orientation 1 is standard. Orientation positions
2 and 4 are not available in some actuator sizes.
Contact Us.
Figure 4 : Transfer Case Mounting

DiskFlo Control Valves
7
Failure Probable Cause Corrective Action
Valve moves to failure position, excessive air  1. Failure of actuator O-ring 1.Replace actuator stem O-ring
bleeding from transfer case 2. Failure of sliding seal assembly 2.Repair or replace stem adapter / linkage assembly
Jerky shaft rotation 1. Overtightened packing 1.Retighten packing box nuts to slightly over finger-tight
 2. Improper adjustment of lever arm on shaft causing arm  2. Readjust lever arm (see step 1 in the
  to contact transfer case thus failing to convert torque.  “Remounting Actuator” section)
 3. Cylinder wall not lubricated 3.Lubricate cylinder wall with silicone lubricant
 4. Worn piston O-ring allowing piston to gall on cylinder wall 4. Replace O-ring; if galling has occurred replace all damaged parts
 5. Worn actuator stem O-ring causing ctuator stem to gall on stem collar  5. Replace O-ring; if actuator stem is galled replace it
 6. Worn (or damaged) shaft bearings, shaft bearings or packing followers  6. Disassemble and inspect parts; replace any worn or damaged parts
Excessive leakage through seal 1. Improper adjustment of external stroke stops  1. See “Adjusting External Stroke Stops” section
 2. Worn or damaged seat  2. Replace seat
 3. Damaged ball seating surface  3. Replace disc and shaft
 4. Improper handwheel adjustment acting as limitstop  4. Adjust handwheel until disc seats properly
 5. Ball not centered in body I.D.  5. Center ball; replace damaged seals.
Leakage through line flanges 1. Dirty line gasket surfaces  1. Clean gasket surfaces and reinstall valve
 2. Improper torque on line flanges  2. Tighten line flanges evenly and completely (see Table 1 for proper torque)
 3. Flange or pipe misalignment  3.Realign flanged ends with piping.
 4. Warn Gaskets  4.Replace Gaskets
Leakage through packing box  1. Loose packing box nuts  1. Tighten packing box nuts to slightly over finger-tight
 2. Worn or damaged packing  2. Replace packing
 3. Dirty or corroded packing  3. Clean body bore and stem, replace packing
Valve slams, won’t open, or  1. Improper valve installation  1. See step 2 in “Installation” section and
causes severe water hammer     correct flow direction
Shaft rotates, ball remains open or closed 1. Broken shaft 1.Replace shaft
Actuator operates, shaft does not rotate  1. Broken internal actuator parts  1. Refer to appropriate actuator Maintenance Instructions
Trouble shooting DiskFlo Valve
Figure 5: Exploded Body Sub-Assembly
Note : Item numbers correspond to bill of material of Valve. Please refer to it for specific part numbers.
Item No. Description
1body
20 hard seat
21 seat insert
22 seat retainer
50 disk
51 shaft
52 taper pins
55 seat gasket
61 O-ring
80 gland flange
83 shaft bearing
85 packing retainer
87 packing follower
88 packing
93 packing spacer
109 packing box stud
117 packing box nut
122 shaft plug
123 clip
124 screw
85
88
93
88
87
80
109
117
51
83
50
83
52
122 61
1
21
55
20/22
123
124

MASCOT VALVES PVT. LTD.
166 / 167, G I D C, Naroda, Ahmedabad : 382330. India
Phone : [phone], Fax : [phone]
Email : [e-mail] / web : www.mascotvalves.com