Graco 312185S Md2 Valve Users Manual Valve, Instructions Parts, English

2015-04-02

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Instructions - Parts

MD2 Valve

312185S
EN

For use with disposable mixers to dispense a variety of sealants and adhesives. For
professional use only.
120 psi (0.84 MPa, 8.4 bar) Maximum Air Inlet Pressure
Important Safety Instructions
Read all warnings and instructions in this
manual. Save these instructions.
See page 2 for model information, including maximum working pressure and approvals.

TI9964A

MD2 Valve Models

Contents
MD2 Valve Models . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Component Identification . . . . . . . . . . . . . . . . . . . . 5
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Graco Standard Warranty . . . . . . . . . . . . . . . . . . . 30
Graco Information . . . . . . . . . . . . . . . . . . . . . . . . . 30

MD2 Valve Models
MD2 Valves
Part No.

Maximum Working Pressure
psi (MPa, bar)

255179
255180
255181

1:1 Soft seat, adjustable snuff-back
3000 psi (20.7 MPa, 207 bar

255182
255183

Description
1:1 Hard seat, non-adjustable snuff-back
Wide ratio, soft seat, adjustable snuff-back
Wide ratio, hard seat, non-adjustable snuff-back

2000 psi (13.8 MPa, 138 bar)

Cold spray/joint fill valve

MD2 Valve Handles
255206

120 psig (0.84 MPa, 8.4 bar)

Air trigger

255208

3A @ 28 VDC

Electric air actuated

255249

0.5 @ 28 VDC

Electric actuated lever

Model Selection
The following table provides a summary of the MD2 dispense valves that are described in this manual.
Type

Description

Hand held valves with
internal air trigger

The internal air trigger controls the air piston that operates the MD2 valve. A pilot port
can be used to control a pump motor.

Hand held valve with
electric switch

The switch signals the customer’s controller to open and close the ports on the MD2
valve using a remote 4-way air control valve which is not included.

Wide ratio valves

The wide ratio MD2 valve has a center injection tip. This feature is helpful with wider
ratio applications, specifically when the low volume material is a much lower viscosity
than the high volume material. Frequent cleaning intervals may be required to maintain
the tip.

Hard seats

Carbide seats and hardened needles are good for abrasive materials and stall against
pressure applications.

Soft seats

UHMWPE seals are good for precise snuff-back control.

312185S

Warnings

Warnings
The following warnings are for the setup, use, grounding, maintenance, and repair of this equipment. The exclamation point symbol alerts you to a general warning and the hazard symbol refers to procedure-specific risk. Refer back
to these warnings. Additional, product-specific warnings may be found throughout the body of this manual where
applicable.

WARNING
SKIN INJECTION HAZARD
High-pressure fluid from dispense valve, hose leaks, or ruptured components will pierce skin. This may
look like just a cut, but it is a serious injury that can result in amputation. Get immediate surgical
treatment.
• Do not point dispense valve at anyone or at any part of the body.
• Do not put your hand over the end of the dispense nozzle.
• Do not stop or deflect leaks with your hand, body, glove, or rag.
• Follow Pressure Relief Procedure in this manual, when you stop spraying and before cleaning,
checking, or servicing equipment.
EQUIPMENT MISUSE HAZARD
Misuse can cause death or serious injury.
• Do not operate the unit when fatigued or under the influence of drugs or alcohol.
• Do not exceed the maximum working pressure or temperature rating of the lowest rated system
component. See Technical Data in all equipment manuals.
• Use fluids and solvents that are compatible with equipment wetted parts. See Technical Data in all
equipment manuals. Read fluid and solvent manufacturer’s warnings. For complete information
about your material, request MSDS forms from distributor or retailer.
• Check equipment daily. Repair or replace worn or damaged parts immediately with genuine manufacturer’s replacement parts only.
• Do not alter or modify equipment.
• Use equipment only for its intended purpose. Call your distributor for information.
• Route hoses and cables away from traffic areas, sharp edges, moving parts, and hot surfaces.
• Do not kink or over bend hoses or use hoses to pull equipment.
• Keep children and animals away from work area.
• Comply with all applicable safety regulations.
TOXIC FLUID OR FUMES HAZARD
Toxic fluids or fumes can cause serious injury or death if splashed in the eyes or on skin, inhaled, or
swallowed.
• Read MSDS’s to know the specific hazards of the fluids you are using.
• Store hazardous fluid in approved containers, and dispose of it according to applicable guidelines.
• Always wear impervious gloves when spraying or cleaning equipment.
PERSONAL PROTECTIVE EQUIPMENT
You must wear appropriate protective equipment when operating, servicing, or when in the operating
area of the equipment to help protect you from serious injury, including eye injury, inhalation of toxic
fumes, burns, and hearing loss. This equipment includes but is not limited to:
• Protective eyewear
• Clothing and respirator as recommended by the fluid and solvent manufacturer
• Gloves
• Hearing protection

312185S

Warnings

WARNING
FIRE AND EXPLOSION HAZARD
Flammable fumes, such as solvent and paint fumes, in work area can ignite or explode. To help prevent
fire and explosion:
• Use equipment only in well ventilated area.
• Eliminate all ignition sources; such as pilot lights, cigarettes, portable electric lamps, and plastic drop
cloths (potential static arc).
• Keep work area free of debris, including solvent, rags and gasoline.
• Do not plug or unplug power cords, or turn power or light switches on or off when flammable fumes
are present.
• Ground all equipment in the work area. See Grounding instructions.
• Use only grounded hoses.
• Hold gun firmly to side of grounded pail when triggering into pail.
• If there is static sparking or you feel a shock, stop operation immediately. Do not use equipment
until you identify and correct the problem.
• Keep a working fire extinguisher in the work area.

312185S

Component Identification

C
B

F
A
D

G
B

TI10391A

FIG. 1: Component Identification
Key:
A
B
C
D
E
F
G
H

Snuff-back adjustment knob (soft seat versions only)
1/8 in. npt (f) air to close (O).
1/8 in. npt (f) air to open (I).
9/16 straight thread o-ring boss “B” fluid inlet (low volume)
9/16 straight thread o-ring boss “A” fluid inlet (high
volume)
Zerk grease fitting
Nosepiece with 7/8-9 bell outlet
Air cylinder

312185S

Features

Features
Electric Switch Valve

Pneumatic Valve

1/4 in npt (f)
air inlet

Series A handle shown

TI10383A
TI10407A

Normally open momentary contact switch
Note: The Trigger/Lever activates an electrical switch in
the handle, which activates a remote 4 way solenoid
valve. Bring an “OPEN” air signal to the 1/8 in. npt(f)
port (I) on this side of the valve, and a “CLOSE” signal
to the port (O). See Accessories, page 23, to order fittings and tubing.

The 1/8 in. npt (f) port (I) can be used to send an “ON”
signal back to a pump pilot or control. See FIG. 1.

Electric Actuated Lever Valve

TI10409A

FIG. 2: Features of the MD2 Valves

312185S

Installation

Installation
Grounding

The following grounding instructions are minimum
requirements for a basic dispensing system. Your system may include other equipment or objects which must
be grounded. Check your local electrical code for
detailed grounding instructions for your area and type of
equipment. Your system must be connected to a
true-earth ground.
•

•

•
•
•

•

Pump: ground the pump by connecting ground wire
and clamp as described in your separate pump
instruction manual.
Air compressors and hydraulic power supplies:
ground the equipment according to the manufacturer's recommendations.
Fluid hoses: use only grounded fluid hoses with a
maximum of 500 feet (150 m) combined hose length
to ensure grounding continuity. Check the electrical
resistance of your fluid hoses at least once a week.
If your hose does not have a tag on it which specifies the maximum electrical resistance, contact the
hose supplier or manufacturer for the maximum
electrical resistance limits, replace the hose immediately.
Dispensing valve: ground the valve by connecting
it to a properly grounded fluid hose and pump.
Fluid supply container: ground according to your
local code.
Flammable liquids in the dispense area: must be
in approved, grounded containers. Do not store
more than the quantity needed for one shift.
All solvent pails used when flushing: ground
according to local code. Use only metal pails, which
are conductive. Do not place the pail on a non-conductive surface, such as paper or cardboard, which
interrupts the grounding continuity.
To maintain grounding continuity when flushing or
relieving pressure, hold a metal part of the valve
firmly to the side of a grounded metal pail, then trigger the valve.

312185S

How to Use the Valve Trigger
Safety

1. If you are using one of the hand-held versions of the
valve, lock the valve trigger safety by turning the
latch to a right angle with the gun body. See FIG. 3.
2. To unlock the valve trigger safety turn it parallel with
the gun body.

LOCKED
TI10442A

UNLOCKED
TI10441A

FIG. 3

Setup

Setup
Fluid and Air Connections

Selecting Hoses

9/16 Straight Thread O-Ring Boss Fluid
Inlets

Hoses between your proportioner and the MD2 valve
should be selected carefully. Many factors effect hose
selection.

There is one fluid inlet on the A-side and one fluid inlet
on the B-side. The fluid inlets are located on the side of
the valve and swivel to permit various mounting and
hose configurations.

1/8 npt(f) Air Inlets
The machine mount valves and the electric switch
hand-held valves have an on port (I) and off port (O),
which are operated by a remote 4-way air control valve.
Use one of the two air inlets located on the bottom and
on the back of the valve.
The air switch hand-held valves have a single air inlet
with an internal 4-way spool which operates the air piston.
See Accessories on page 19, to order air control valves
and tubing.

Inlet Check Valves
Inlet check valves are recommended on the fluid inlets
where viscosity allows. An inlet check valve prevents
back-flow or crossover when the mixer is plugged or one
fluid is much lower viscosity than the other. When
required, a high crack pressure check valve is installed
to maintain back-pressure on low viscosity fluids.

1. Fluid Compatibility: Fluid must not degrade the
core material or end fittings of the hose. Nylon or
PTFE cores are commonly used for chemical compatibility. If your fluid is moisture sensitive you
should use PTFE or Moisture-Lok hoses.
2. Pressure Rating: Be sure hoses have a working
pressure rating above the pressure capability of the
system.
3. Compressibility: Hoses, especially nylon paint
hoses, expand with an increase in pressure. A pressure change in the system may cause a volume
change, which can appear as a ratio error with wide
mix ratios. Compressible hoses absorb pressure
spikes which is helpful to the operator during an
application, such as trying to lay a bead.
4. Internal Diameter: Small I.D.'s create higher back
pressures, lower flows, and small retained volume.
Typically hose I.D.'s are selected for:
a. System Pressure Balance. “A” pressure drop
vs. “B” pressure drop.
b.

Volume Balance. A:B volume ratio vs. Hose
retained volume.

Flexibility and weight for operator or robot.

See Accessories on page 19 for a list of check valves.

Balancing the System
A proportioner is used to feed the two-component dispense valve. The system must be pressure balanced to
avoid “lead-lag” ratio errors when starting and stopping
the flow.

d. Overall Pressure Drop. Pressure drop should be
minimum possible within the above guidelines.
5. Length: Hoses normally are kept as short as practical to minimize pressure drop and compressible volume. 10 ft (3.1 m) is recommended for reciprocating
pump systems.

Balancing is done by hose sizing or inlet check restriction. A properly balanced system has near equal
back-pressure on the gauges when flowing without a
mixer installed.

312185S

Setup

System Start-up
When initially loading the fluids through the system,
leave the mixer off until both fluids flow freely from the
nose piece without any air. This prevents cross contamination from having fluid on one side pushing back up the
other side.

Mixer Selection
Disposable mixers are available from 3/16 in. I.D. to 1/2
in. I.D. in lengths from 12 elements to 36 elements. In
general, wide viscosity or mix ratios require more mix
elements. Small I.D. mixers produce lower flow, higher
back-pressure, and waste little material. Large I.D. mixers produce higher flow, lower back-pressure, and fewer
lead-lag ratio errors. Different mixers can have differing
snuff-back characteristics.

Setting the Amount of
Snuff-back
NOTE: For Models 255179 and 255181 only

The MD2 valves with hard seats use two snuff-back
restrictor rings (13) to set the amount of snuff-back.
These two rings are trapped between the main valve
body and the nose piece. When the fluid valve pulls
back to close, it enters the restrictions, stops flow, and
pulls the fluid back until the needle reaches its carbide
seat.
Maximum snuff-back results when both restrictors are
used. Some snuff-back is still achieved without the
restrictors because of the pull-back action of the needles.
When dispensing wide mix ratios, it is best to use a
snuff-back restrictor only on the high volume side. This
keeps the high volume side from being pulled back into
the low volume side.
The MD2 valves with soft seats have an adjustable
snuff-back. Turn the knob on the back of the soft seat
MD2 valve to adjust the amount of snuff-back.
In general, use only as much snuff-back as necessary to
give a good cut-off of flow. Too much snuff-back pulls an
air bubble into the mixer. This can cause a drip, or cause
the mixer to spit when the valve is re-opened.

312185S

Operation

Operation
Pressure Relief Procedure

•

1. Shut off the air to the supply pumps.
2. Close the bleed-type master air valve (required in
your system).
3. Hold a metal part of the valve firmly to the side of a
grounded metal pail, and trigger the dispense valve
to relieve pressure.
4. Shut off the air to the dispense valve, if applicable.
If you suspect that the dispense needle or hose is completely clogged, or that pressure has not been fully
relieved after following the steps above, very slowly
loosen the hose end coupling and relieve pressure gradually, then loosen completely. Now clear the needle or
hose.

Lever Actuated Valve and
Electric Switch Hand-held Valve
•
•

•

Be sure the air supply lines are connected correctly
to the (I) and (O) valve air ports.
To open or close the valve and maintain the open or
closed status, a minimum of 40 psi (280 kPa, 2.8
bar) air pressure must be supplied and maintained
at the (I) or (O) port.
The trigger and lever only activates the electrical
switch in the handle, which turns the remote solenoid on and off. See page 20 for electrical diagram.
Trigger the gun or pull the lever to turn the solenoid
on. Release the trigger or lever to turn the solenoid
off.

Apply and maintain air pressure to the ON (I) air
port on the valve, and remove air pressure from the
OFF (O) air port on the valve to open the valve.
Apply and maintain air pressure to the OFF (O) air
port on the valve, and remove air pressure from the
ON (I) air port on the valve to close the valve.

Pneumatic Hand-held Valve
The valve operation is such that it is either fully open or
fully closed.
The valve is opened and closed by the internal air control valve. Trigger the gun to open the valve. Release the
trigger to close the valve.

Ratio Checking
The output mix ratio of your proportioner can be
checked by dispensing the two fluids separately out of
the nosepiece into tared cups. The cups can then be
weighed and the weights divided to get the mix ratio by
weight.
Use ratio check nozzles 255247 with 15K688 retaining
nut for 1:1 models, or 255245 with 15K688 retaining nut
for 10:1 models to make ratio checks.
Ratio checks provide information on the ratio of an overall sample. Transient problems (soft spots) caused by
starting and stopping the flow (lead-lag) may not show
up in this kind of ratio check. Physical tests of the mixed
fluid are the best check of correct ratio and mix quality.

Machine Mount Valve
•
•

Be sure the air supply lines are connected correctly
to the ON (I) and OFF (O) valve air ports.
To open or close the valve and maintain the open or
closed status, a minimum of 40 psi (280 kPa, 2.8
bar) air pressure must be supplied and maintained
at the ON (I) or OFF (O) port.

312185S

Maintenance

Maintenance
Daily Shutdown
When you are through using the MD2 valve, the outlet to
the mixer should be cleaned and protected from drying
or crystallization.

1. Remove and properly dispose of the static mixer.
2. Dispense a shot of material into a waste container
to clear any crossover in the nosepiece.
3. Wipe the nose with a clean rag being careful not to
let the materials contact each other.
4. Install the PTFE night cap (1:1 valves - 15K652,
10:1 valves - 15K628) and retaining nut (15K688).

Preventive Maintenance
There is a grease filled secondary seal/bearing area on
each valve shaft. Every 10,000 cycles, or twice each
month, new grease should be flushed across this area.
To grease the valve:
1. Remove the zerk grease fitting from each side of the
front or back of the valve.
2. Pump grease (115982) with grease gun (117792)
across the valve until clean grease comes out of the
other side.
3. Reinstall the zerk grease fitting.

312185S

Troubleshooting

Problem
Valve does not open.

Valve does not close and leaks.

Cause

Solution

Insufficient air pressure.

Turn on air or increase air pressure.

Air not exhausted from the front side
of air cylinder piston.

Use 4-way, relieving type air valve.

Insufficient air pressure.

Turn on air or increase air pressure.

Air not exhausted from the back side Use 4-way, relieving type air valve.
of air cylinder piston.
Blockage between needle and seat.

Remove and clean needle and seat.

Damaged or missing gasket between Replace gasket (38).
seat and housing (hard seat only).

Higher than normal back pressure.
Soft spots in mixed material.

Low flow rate.

Damaged or worn needle or seat.

Replace both the needle and seat.

Too little snuff-back.

Unscrew snuff-back adjustment needle (25) 1/4 turn at a time.

Nose piece is clogged.

Remove and clean.

Mixer is curing.

Replace mixer.

Nose piece is clogged on one side.

Remove and clean.

System is not properly balanced.

Balance system with hoses, check
valves, restrictors.

High static pressures build when
valve shuts off.

Turn off proportioner pump when
valve closes.

Snuff-back rings (13) are installed
(hard seat only).

Remove snuff-back rings if they are
not required for maximum snuff-back.

312185S

Repair

Repair
Disassembly

5. Remove the two fluid housing screws (18) and
clamps (17) from the fluid housing (14). Slide the
fluid housing (14) off of the air cylinder (2). See FIG.
5.
6. Remove the bearings (11), bearing o-rings (36, 13),
and secondary fluid seals (12, 15).

1. Relieve all air and fluid pressure, page 10.
2

2. Disconnect the valve from the system.

16
11

NOTE: In the following steps, keep the parts
from the A side and B side separate to prevent
cured material from forming on them.

3. Remove the two nosepiece screws (19), and pull the
nosepiece (29) away from the valve. Remove the
needle seats (27) and o-rings (20) for the 255179
and 255181 models. See FIG. 4.

14 15

4. 255179 and 255181 only: use a 5/32 in. socket
(4mm) to unscrew the needle (25). If the shaft (5)
spins, insert a dowel pin in the shaft hole to hold it
steady, then unscrew the needle. Slide the seal (26)
off the needle. Repeat for the other needle (25).

17
18

TI9974A

FIG. 5
255180 and 255182 models: use a 3/32 pin punch
to remove the needle, then remove the seats (27)
and gaskets (28) from the inlet housing.

20 14

27
25
19

29
TI9972A

FIG. 4

312185S

Repair

7. Remove the retaining ring (1) from the back of the
air cylinder (2). Push the two shafts (5) into the air
cylinder (2) to dislodge the air cylinder cap (22). See
FIG. 6.

204

210

8. Push the two shafts (5) to dislodge the piston (9)
assembly from the air cylinder (2).

213
203
202

9. Use an o-ring pick to remove the o-rings (23) and
use a screwdriver to remove the sleeve bearings (7)
from the air cylinder (2).

203

10. Remove the o-rings (6) from the piston (9) and air
cylinder cap (22).
11. Remove the screw (24) and snuff-back adjustment
knob (21) from the cap (22). Use an o-ring pick to
remove the o-ring (23).

214
205
212

FIG. 7

Electric Switch Handle (if equipped)

TI10408A

206

201
12. Remove the lock nuts (3), the pin (8), o-rings (4),
and piston o-ring (6) from the shaft (5).

211

1. Disconnect the power from the gun.

22
3

23
24
39

2. The switch and cable are not repairable. Replace
these parts as a complete assembly. Use kit 255463
for series A handles. Use kit 24D049 for series B
handles.
3. Loosen the relief connector (112) and remove the
air valve plug (111).

2
6
9
4

4. Remove the wire which will take the electric
switch (114) and spacer (115) with it.

8
TI9975B

FIG. 6
112

Pneumatic Handle (if equipped)

115 111
114

1. Remove the four screws (214). Pull the handle (205)
and gasket (204) away from the air cylinder (2).

113

2. Unscrew air valve plug (211) and remove spring
(213). Using a small diameter tool, push spool (202)
out from front. Inspect o-rings (203).

116

120
101
TI10384B

104
FIG. 8

312185S

Repair

Reassembly

6. 255179 and 255181, Insert the seals (26) with the
springs facing into the fluid housing (14).

Air Cylinder Section

7. With the “X” on the nosepiece on the same side as
the “MD2” on the air cylinder, install the nosepiece
(31) with the o-rings (20), seats (27), and nosepiece
screws (19). Tighten the nosepiece screws to
115-120 in-lb (14-15 N•m).

1. Lubricate the shaft o-rings (23) and the bearings (7).
Insert o-rings into the air cylinder (2) and air cap
(22) cavities.See FIG. 6.
NOTE: The snuff-back adjustment knob (21),
shaft o-rings (23), and screw (24) are not present in models 255180, 255182, and 255183.
2. 255179 and 255182 only: Insert the snuff-back
adjustment knob (21) in the cap (22). Tighten the
screw (24) on the end of the snuff-back adjustment
knob (21). Torque to 25-30 in.-lb (2.8-3.4 N•m).
3. Press the bearings (7) flush into the air cylinder
housing (2) and air cap (22), trapping the o-rings
(23).
4. Lubricate and reassemble the piston assembly: piston (9), o-ring (6), dowel pin (8), nuts (3), o-ring (4),
and air cylinder shafts (5). Tighten nuts (3) to 25-30
in-lb (2.8-3.4 N•m). The shafts (5) should hang with
some play to be self-aligning in the bearing.
5. Lubricate the air cylinder (2) ID. Push the piston (9)
assembly into the air cylinder.
6. Lubricate and assemble the o-ring (6) onto cap (22).
Push cap (22) into cylinder (2).
7. Install the outside retaining ring (1).

Fluid Section
1. Lubricate the bearings (11), o-rings (13, 36) and
seals (12, 15). Put the o-rings (13, 36) on the bearings. Carefully insert the seals (12) into the bearing
recess, with the lips of the seals facing into the bearing. Insert the seals (15) into the bearing with the
spring facing out of the housing. Be careful not to
damage the seal lips. See FIG. 5.
2. Push the bearings (11) into the air cylinder (2).
3. Grease the fluid housing (14) and install over the
bearings (11). Install the clamps (17) and screws
(18). Tighten to 25-30 in-lb (2.8-3.4 N•m).

8. 255181 and 255182, Install injector tube (30) with
assembly tool (48). Torque to 168-192 in-lb
(19.0-21.7 N•m).
9. 255181 and 255182, Install injector tip (47) and
torque to 60-72 in-lb (6.8-8.1 N•m).
10. Remove zerk grease fitting (39). Fill grease in the
grease port below until grease begins to exit where
the zerk grease fitting (39) was located. Repeat for
the other zerk grease fitting (39). See FIG. 6.

Pneumatic Handle (if equipped)
1. Liberally lubricate o-rings (203) and reassemble.
Install spool (202) and spring (213). Torque plug
(211) to 125-135 in-lb (14-15 N•m). See FIG. 7.
2. Align the gasket (204) and dispense valve on the
top of the handle (205). Torque the four screws
(214) evenly to 15-20 in-lb (1.7-2.2 N•m).

Electric Switch Handle (if equipped)
1. Install the plunger (113) and spring (116). See FIG.
8.
2. Insert the switch assembly (255463) while routing
the ground lug (108) through the hole in the top of
the handle.
3. Torque plug (111) to 125-135 in-lb (14-15 N•m).
4. Tighten the strain relief (112).
5. Install the ground screw (110) through the lock
washer (109) and ground lug (108). Torque to 15-20
in-lb (1.7-2.2 N•m).
6. Align the dispense valve on the top of the handle
(101). Torque the four screws (120) evenly to 15-20
lb (1.7-2.2 N•m).

4. For 255180 and 255182, insert the gaskets (28) and
seats (27).
5. Screw in the needle (25) and tighten it to 25-30 in.-lb
(2.8-3.4 N•m). See FIG. 4.
312185S

Parts

Parts
255179 and 255181
29
2

255181

47 30

12✖

11
13✖
36✖
15✖
2

29
14
20*†
26*

27*
1

4❖✖

25*

5✖
8
7❖
39

23❖

21
1
22

Torque to 25-30 in-lb (2.8-3.4 N•m).

Torque to115-120 in-lb (14-15 N•m).

TI21240A

6❖

312185S

Parts

MD2 Valve
The parts listed below are common to all MD2 Dispense
valves. Parts which vary are found in the table at the bottom of this page.
Ref
1
2
3
4❖✖
5✖
6❖
7❖

Part
120762
15K496
102920
157628
15K421
156593
551181

8
9
11
12✖
13✖
14
15✖
16
17
18

551183
626067
15K422
551191
113746
15K441
120768
15K442
15K444
121224

Description
RING, retainer
HOUSING, air cylinder
NUT, lock
O-RING, buna-n
SHAFT, primary
O-RING, buna-n
BEARING, sleeve 1/4, 3/8, 1/4,
nylon
PIN, dowel 1/8 x 1.25 18-8 sst
PISTON, air cylinder
BEARING, seal
PACKING, u-cup, nitrile
O-RING
HOUSING, inlet
SEAL, UHMWPE
SPACER, valve
CLAMP, adapter, inlet
SCREW, cap, socket head, M5 x
0.8 x 8 mm

Ref.
No. Description

KNOB, snuff-back, adjust
22a CAP, air cylinder, snuff-back
❖23 O-RING, buna-n
24 STOP, snuff-back
25 NEEDLE, snuff-back
26 SEAL, UHMWPE
27 SEAT, needle
29 HOUSING, nose
30 TUBE, injector, sst
31 CAP; not shown

40
47
48

ADAPTER, ratio check
TIP, injector
TOOL, assembly aid; not shown

312185S

Qty
1
1
2
2
2
2
2
1
1
2
2
2
2
2
2
2
2

1:1
255179
15K419

Ref
19

Part
Description
Qty
107530 SCREW, cap, socket head, high
2
strength
20*† 117517 O-RING, fluoroelastomer
2
32
15K688 NUT, mixer; not shown
1
33
104765 PLUG, pipe, headless; not shown
2
36✖ 118594 O-RING, fluoroelastomer
2
38
551189 LUBRICANT, grease 3 oz. car1
tridge; not shown
39
120892 FITTING, grease
4
❖ Parts included in Valve Air Cylinder Repair Kit
255217 (purchase separately).
✖ Parts included in Valve Lube Seal Repair Kit 255218
(purchase separately).
*

Parts included in Front Valve Repair Kit 255219 (purchase separately).

† Parts included in Front Valve Repair Kit 255220 (purchase separately).

10:1
255181

Qty

15K419

15K420

156454

15V627

*15K428
*120784
*15K460

15K445

2
2

15K649

15V624

15K652

15V628

255247

256794
15V623
256793

1
1
1

Parts

255180, 255182, and 255183
16

29
29

255182 47 30

12✖

11
13✖
36✖
15✖
2

19
14

26†

28†

20*†

27†
4❖✖

25†

5✖
8
7❖
39

23❖

1
6
22
1

Torque to 25-30 in-lb (2.8-3.4 N•m).

Torque to115-120 in-lb (14-15 N•m).

TI21241A

6❖
9

312185S

Parts

MD2 Valve
The parts listed below are common to all MD2 Dispense
valves. Parts which vary are found in the table at the bottom of this page.
Ref
1
2
3
4❖✖
5✖
6❖
7❖

Part
120762
15K496
102920
157628
15K421
156593
551181

8
9
11
12✖
13✖
14
15✖
16
17
18

551183
626067
15K422
551191
113746
15K441
120768
15K442
15K444
121224

Ref.
No. Description

CAP, air cylinder
❖23 O-RING, buna-n
25 NEEDLE, snuff-back
26 SEAL, UHMWPE
27 SEAT, needle
28 GASKET, seat
29 HOUSING, nose
30 TUBE, injector, sst
31 CAP; not shown
22

40
47
48

ADAPTER, ratio check
TIP, injector
TOOL, assembly aid

312185S

Qty
1
1
2
2
2
2
2
1
1
2
2
2
2
2
2
2
2

1:1
255180

Ref
19
20*†
32
33
36✖
38
39
42

Part
107530
117517
15K688
104765
118594
551189

Description
Qty
SCREW, high strength
2
O-RING, fluoroelastomer
2
NUT, mixer; not shown
1
PLUG, pipe, headless; not shown
2
O-RING, fluoroelastomer
2
LUBRICANT, grease 3 oz. car1
tridge; not shown
120892 FITTING, grease
4
299518 CAP, plug; not shown
2

❖ Parts included in Valve Air Cylinder Repair Kit
255217 (purchase separately).
✖ Parts included in Valve Lube Seal Repair Kit 255218
(purchase separately).
*

Parts included in Front Valve Repair Kit 255219 (purchase separately).

† Parts included in Front Valve Repair Kit 255220 (purchase separately).

1:1
255183

10:1
255182

Qty

15K447

156454

† 626062
† 185467
† 626060
† 171860

† 626062
† 185467

† 171860

† 626062
† 185467
† 626060
† 171860

15K445

16T648

15K649

2
2
2

15V624

15K652

15V628

255247

24P850
15V623
256793

1
1
1

Parts

Electric Switch Handle, 255208
NOTE: Extension cable 123660 is available.

112*
1
1

105

111*

115*

106

114*
116
113

120
119*
104
101

TI14761A

TI10384B

Series B handle shown

Torque to 25 in-lb (2.8 N•m).

Torque to 125-135 in-lb (14-15 N•m).

Ref
101

Part
Description
Qty
1
15K666 HANDLE, 2K, dispense valve,
electric
104 15B209 TRIGGER, gun
1
105 192272 PIN, pivot
1
106 203953 SCREW, cap, hex hd, 10-24
1
UNC-3A x 3/8
111*
PLUG, air valve
1
112*
CONNECTOR, relief 1/4 npt
1
113 15K668 PLUNGER, trigger, 2K handle
1
114*
SWITCH, elect mini snap action
1
115*
SPACER, switch
1
116 551396 SPRING, 0.26X, 0.37X, 0.51 music
1
wire
119*
CABLE, trigger, female, 3-pin con1
nector (Series A Handles Only)
CABLE, trigger, male, 4-pin con1
nector (Series B Handles Only)
120 117026 SCREW, cap, sch, M5 x 0.80 x
4
12 mm
* Parts included in Series A Handles Kit 255463 and
Series B Handles Kit 24D049 (purchase separately).

312185S

Parts

Pneumatic Handle, 255206

204
216
4

210

215

213
203

211

202
203

214

207

Torque to 35 in-lb (4 N•m).

205

Apply lubricant on seals.

Apply thread sealant. Torque to 130 in-lb (15 N•m).

Torque to 25 in-lb (2.8 N•m).

212
206
3

201
TI21242A

Ref
201
202
203*
204
205
206
207
210
211
212
213
214
215
216
*

Part
Description
Qty
100721 PLUG, pipe
1
15B202 VALVE, spool
1
O-RING, chemically resistant fluorocarbon 3
15K661 GASKET, handle
1
15K658 HANDLE, 2K dispense valve, air
1
119626 PLUG, breather
1
192272 PIN, pivot
1
203953 SCREW, cap hex hd, 10-24 UNC-3A x 3/8
1
15B208 PLUG, air valve, 1/4 npt
1
15B209 TRIGGER, gun
1
117485 SPRING, compression
1
117026 SCREW, cap, sch, M5 x 0.80 x 12 mm
4
117509 COUPLER, line, air, 1/4 npt
1
117510 FITTING, line, air, 1/4 npt
1

Parts included in Kit 246354 (purchase separately).

312185S

Parts

Actuated Lever, 255249

302
305

307

319

303
304
308

306
310

301

309
303
1

Torque to 25 in-lb (2.8 N•m).

TI10410B

Ref
301
302
303
304
305
306
307
308
309
310
311
319

Part
15K922
121191
100015
100016
192272
203953
551318
121192
121193
15M479
121194

Description
BLOCK, mounting lever, 2K
BOLT, eye, 1/4-20 x 2 in. (51 mm)
NUT, hex, 1/4-20 UNC 2-B
WASHER, lock
PIN, pivot
SCREW, cap, hex, hd
CONNECTOR, relief, 1/4 npt
SWITCH, pushbutton
PLUNGER, spring, 1/4-20
LEVER, actuator, valve
SCREW, socket head cap, M5 - 0.8 x
30 mm (not shown)
123619 CABLE, trigger

Qty
1
1
2
1
1
1
1
1
1
1
4
1

312185S

Accessories

Accessories
Plastic Tube Fittings to Connect Air Signals
Tube OD

1/8 NPT (M) Straight

1/8 NPT (M) 90° Swivel

5/32 in.
1/4 in.

114263
115671

114151
112698

Tube OD

1/4 NPT (M) Straight

1/4 NPT (M) 90° Swivel

5/32 in.
1/4 in.

598252
104165

114469
114109

Inlet Check Valves (3000 psi working pressure)
Part No.

Size

501867
501684
949709
949710

1/4 NPT (M x M)
3/8 NPT (M x M)
3/8 NPT (M x M)
3/8 NPT (M x M)

Description
303 sst with PTFE o-ring poppet (2 psi crack pressure).
303 sst with PTFE o-ring poppet (2 psi crack pressure).
Carbon steel carbide seat (50 psi crack pressure).
Carbon steel carbide seat (100 psi crack pressure).

Catalyst Injectors
Catalyst injectors are restrictive check valves which are often used to create back pressure on the catalyst side inlet
to the MD2 valve. Catalyst injectors are also used to balance pressures and flow on wide-ratio, low-viscosity catalyst
applications.

Injector No.

Size Code

Bore Dia.

Needle Dia.

Typical
Application
Viscosity

948291

#125

0.125 in.

0.086 in.

500-50,000 cps

Polysulfide

948258

#35

0.110 in.

0.086 in.

1000-10,000 cps

Silicone

947937

#40

0.098 in.

0.086 in.

200-1,500 cps

Urethane

570251

#42

0.0935 in.

0.086 in.

50-800 cps

Urethane

Typical Used
Sealant*

* Wide ratio applications 8:1 to 13:1 by volume.
** Injectors have a “snout” and must be screwed into a 1/4 npt(f) female coupling. Inlet is 1/4 npt(f).

312185S

Accessories

Plastic Tubing for Air Signal Lines
Part No.

Description

514607

5/32 in. O.D. Nylon

C12509

1/4 in. O.D. Nylon

Mixers and Shroud
ID x # elements

50 pack

250 pack

Shroud

3/16 x 32

LC0077

LC0084

LC0063

1/4 x 24

LC0078

LC0085

LC0057

3/8 x 24

LC0079

LC0086

LC0058

3/8 x 36

LC0080

LC0087

LC0059

3/8 Combo

LC0081

LC0088

LC0060

3/16 x 32 Luer Lock

LC0082

LC0089

LC0061

1/4 x 24 Luer Lock

LC0083

LC0090

LC0062

Nose Piece Accessories
Part No.

Description

15K652

1:1 nightcap

PTFE cap to protect the 1:1 outlet when not in use

15V628

10:1 nightcap

PTFE cap to protect the 10:1 outlet when not in use

255247

1:1 ratio check nozzle

Splits the flow on 1:1 valves to facilitate ratio checks

24P850

10:1 ratio check nozzle

Splits the flow on 10:1 valves to facilitate ratio checks

258687

10:1 check tip

Assembly for low volume side material that is very thin

256793

Tool

Assembly tool to aid in the installation and removal of
injector tube 15V623

15K688

7/8-9 retaining nut

Use to hold 15K652, 255247 and 255245 on to valve

Notes

312185S

Accessories

Orifice Kits
In the following table, shaded rows indicate “Super Standard” items that are typically stocked and provide the best
delivery dates.
Impingement
Kit Type and Kit Number
Impingement
Kit Type and Kit Number
Port
Size
Port Size
250 Model Polyol 250 Model Iso
250 Model Polyol 250 Model Iso
in.
mm
Orifice Kit
Orifice Kit
in.
mm
Orifice Kit
Orifice Kit
0.016

0.41

24C805

24D229

0.047

1.19

24C753

24D225

1.32

24C811

24D235

0.020

0.51

24C751

24D223

0.052

0.024

0.61

24C806

24D230

0.055

1.40

24C812

24D236

0.028

0.71

24C807

24D231

0.060

1.52

24C754

24D226

0.031

0.79

24C752

24D224

0.063

1.60

24C813

24D237

1.70

24C755

24D227

0.035

0.89

24C808

24D232

0.067

0.039

0.99

24C809

24D233

0.073

1.85

24C815

24D238

0.042

1.07

24C810

24D234

0.086

2.18

24C756

24D228

Orifice Kit
504
503
502
501

505

Apply a light coating of lubricant to seals and surfaces
specified.

Fasten stem (505) into housing (501). Fasten
cap (509) onto housing (501) and torque to 60-70 in-lb
(6.8-7.9 N•m). Unscrew stem (505) until it bottoms out
against cap (509).

3
3

507
3

ti21829a2

506
509

Ref.
501
502†‡
503†
504†◆
505
506†
507†
509
510

Part
-------------------

Description
Qty.
HOUSING, orifice
1
O-RING, 0.63 in. diameter
1
O-RING, 0.44 in. diameter
1
O-RING, 0.37 in. diameter
1
STEM, valve
1
RING, backup, PTFE
1
O-RING, 0.28 in. diameter
1
CAP, orifice
1
TOOL, cleanout; #78 drill bit (not
1
shown)

† Parts included in kit 24D321.
‡ Parts included in kit 248130 (pack of 6).
◆ Part included in kit 248128 (pack of 6).

312185S

Accessories

24E505 Orifice Block Kit
Part 122737, Swivel Adapter - JIC 6 x 1/4 npt,
not included in kit

Part 122961, Swivel Adapter - JIC 5 x 1/4 npt,
not included in kit
401

402b
402a 1 2
MD2 Valve not included
401d
401b
401c
401a

ti21829a1

1 Lubricate all o-rings and specified surfaces.
2 Torque to 20-30 in-lb (2.2-3.4 N•m).
Ref.
401
401a
401b
401c
401d
402
402a
402b

Part

123886

117724

Description
Qty.
HOUSING, orifice, assy;
1
includes 401a-401d
HOUSING, orifice
1
WASHER
1
NUT
1
O-RING
1
KIT, orifice block plug; includes
1
402a and 402b
PLUG, orifice
1
O-RING
1

24E505 does not include an MD2 valve. See MD2
Valve Models on page 2.
24E505 does not include swivel adapters. Swivel
adapters 122961 and 122737 must be purchased
separately.
See manual 3A0861 for ratio check assembly
24F227.

312185S

Accessories

Valve Accessories
551351 Short Throw Spacer

123660 Extension Cable, 6.0 m (19.7 ft)

A spacer under the air piston that limits how far the fluid
needles push open. It reduces the amount of material
surge when the valve opens, and reduces the amount of
snuff-back available. Used for dispensing low flow small
diameter beads. For 255180 and 255182 only.

For locating the valve further from the base system than
allowed with the original cable provided. For use with the
electric handle 255208 and actuated lever 255249.

Conversion Kits
Part No.

Description

Notes

255206

Pneumatic Handle

Convert any valve to a hand held valve with an internal
pneumatic 4-way valve. See page 21.

255208

Electric Handle

Convert any valve to a hand held valve with an internal normally open switch. See page 20.

255249

Electric Lever Switch

Convert any valve to a hanging valve with an internal normally open switch. See page 22.

255273

Hanger Adapter

Add to any hand held valve to allow it to be hung.

123902

Cable

Replaces trigger cable included with electric handle 255208
and actuated lever 255249. For converting handle/lever to
connect to systems previously connected to a TwinMixer®
gun. Use pins 1 (brown) and 3 (blue).

Hanger Adapter

255273

TI10512A

312185S

Accessories

Front Valve Repair Kits

Angled Adapter Kits

Part No.

Description

255219

Repair Kit for adjustable
snuff-back valves 255179 and
255181 only.

255220

Repair Kit for non-adjustable
snuff-back valves 255180,
255182, and 255183 only.

G 1/2 Outlet Kit
Part No.

Description

16T802

Adapter to allow for the mounting
of G 1/2 threaded mixers. Applicable for 10:1 MD2 valves only.

24W045 - 25° angle
24W046 - 15° angle
24W047 - 5° angle
Ref.

Part

Description

Qty.

601

17B515

25° adapter block

17B516

15° adapter block

17B517

5° adapter block

602

15K661

GASKET, handle

603

117026

SCREW, socket head, M5x12

602
xo

603
601
602

r_16t802

312185S

Technical Data

Technical Data
Maximum Fluid Pressure

255179-255182: 3000 psi (20.7 MPa, 207 bar)
255183: 2000 psi (13.8 MPa, 138 bar)
120 psi (0.84 MPa, 8.4 bar)
1/8 npt(f)
9/16 straight thread o-ring boss “A” and “B”
7/8-9 bell outlet

Maximum Cylinder Air Pressure
Air Inlets (open (I) and close (O) ports)
Fluid Inlets
Fluid Outlet
Fluid Viscosity Range
Soft Seats
Hard Seats
Fluid Section Sealing
Divorced Air Cylinder
Weight
255179 / 255180 (1:1 valves)
255181 / 255182 (10:1 valves)
255206 (pneumatic handle)
255208 (electric handle)
255249 (electric lever)
Wetted Parts
Stainless Steel Valve

1-1 million cps
20-1 million cps
Isolation chamber with zerk fittings and dual seals.
Double acting, buna-n o-rings
1.45 lb (0.66 kg)
1.50 lb (0.68 kg)
0.85 lb (0.39 kg)
0.90 lb (0.41 kg)
0.75 lb (0.34 kg)
303 sst, 17-4 SS, UHMWPE, PEEK, Chemical Resistant
o-rings. 440C SS and C2 carbide with cobalt binder (hard
seat only)

Dimensions
1.06 in. (26.9 mm)
0.28 in. (7.1 mm)

M5 x 0.8 mounting
holes (4)

4.60 in. (116.8 mm)

5.64 in. (143.3 mm)

TI9977A

312185S

0.73 in. (18.5 mm)

0.73 in. (18.5 mm)
4.29 in. (109 mm)

6.64 in. (168.7 mm)

M5 x 0.8 mounting holes (2)

TI10654A

Graco Standard Warranty
Graco warrants all equipment referenced in this document which is manufactured by Graco and bearing its name to be free from defects in
material and workmanship on the date of sale to the original purchaser for use. With the exception of any special, extended, or limited warranty
published by Graco, Graco will, for a period of twelve months from the date of sale, repair or replace any part of the equipment determined by
Graco to be defective. This warranty applies only when the equipment is installed, operated and maintained in accordance with Graco’s written
recommendations.
This warranty does not cover, and Graco shall not be liable for general wear and tear, or any malfunction, damage or wear caused by faulty
installation, misapplication, abrasion, corrosion, inadequate or improper maintenance, negligence, accident, tampering, or substitution of
non-Graco component parts. Nor shall Graco be liable for malfunction, damage or wear caused by the incompatibility of Graco equipment with
structures, accessories, equipment or materials not supplied by Graco, or the improper design, manufacture, installation, operation or
maintenance of structures, accessories, equipment or materials not supplied by Graco.
This warranty is conditioned upon the prepaid return of the equipment claimed to be defective to an authorized Graco distributor for verification of
the claimed defect. If the claimed defect is verified, Graco will repair or replace free of charge any defective parts. The equipment will be returned
to the original purchaser transportation prepaid. If inspection of the equipment does not disclose any defect in material or workmanship, repairs will
be made at a reasonable charge, which charges may include the costs of parts, labor, and transportation.
THIS WARRANTY IS EXCLUSIVE, AND IS IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO WARRANTY OF MERCHANTABILITY OR WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE.
Graco’s sole obligation and buyer’s sole remedy for any breach of warranty shall be as set forth above. The buyer agrees that no other remedy
(including, but not limited to, incidental or consequential damages for lost profits, lost sales, injury to person or property, or any other incidental or
consequential loss) shall be available. Any action for breach of warranty must be brought within two (2) years of the date of sale.
GRACO MAKES NO WARRANTY, AND DISCLAIMS ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE, IN CONNECTION WITH ACCESSORIES, EQUIPMENT, MATERIALS OR COMPONENTS SOLD BUT NOT
MANUFACTURED BY GRACO. These items sold, but not manufactured by Graco (such as electric motors, switches, hose, etc.), are subject to
the warranty, if any, of their manufacturer. Graco will provide purchaser with reasonable assistance in making any claim for breach of these
warranties.
In no event will Graco be liable for indirect, incidental, special or consequential damages resulting from Graco supplying equipment hereunder, or
the furnishing, performance, or use of any products or other goods sold hereto, whether due to a breach of contract, breach of warranty, the
negligence of Graco, or otherwise.
FOR GRACO CANADA CUSTOMERS
The Parties acknowledge that they have required that the present document, as well as all documents, notices and legal proceedings entered into,
given or instituted pursuant hereto or relating directly or indirectly hereto, be drawn up in English. Les parties reconnaissent avoir convenu que la
rédaction du présente document sera en Anglais, ainsi que tous documents, avis et procédures judiciaires exécutés, donnés ou intentés, à la suite
de ou en rapport, directement ou indirectement, avec les procédures concernées.

Graco Information
For the latest information about Graco products, visit www.graco.com.
TO PLACE AN ORDER, contact your Graco distributor or call to identify the nearest distributor.
Phone: 612-623-6921 or Toll Free: 1-800-328-0211 Fax: 612-378-3505

All written and visual data contained in this document reflects the latest product information available at the time of publication.
Graco reserves the right to make changes at any time without notice.
For patent information, see www.graco.com/patents.
Original instructions. This manual contains English. MM 312185

Graco Headquarters: Minneapolis
International Offices: Belgium, China, Japan, Korea
GRACO INC. AND SUBSIDIARIES • P.O. BOX 1441 • MINNEAPOLIS MN 55440-1441 • USA
Copyright 2007, Graco Inc. All Graco manufacturing locations are registered to ISO 9001.
www.graco.com
Revised June 2014

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.4
Linearized                      : Yes
Page Mode                       : UseOutlines
XMP Toolkit                     : 3.1-701
Producer                        : Acrobat Distiller 7.0 (Windows)
Copyright                       : 2007, Rev S June 2014
Job Ref                         : A107M, Z089340
Marked                          : True
Keywords                        : "312185, MD2 Valve, 255179, 255180, 255181, 255182, 255206, 255208, 255249, 312185S, 312185EN, 312185EN-S, MM 312185 "
Web Statement                   : 312185S - MD2 Valve, Instructions - Parts, English
Modify Date                     : 2014:06:12 12:29:18-05:00
Creator Tool                    : FrameMaker 9.0
Create Date                     : 2005:04:27 11:19:54Z
Metadata Date                   : 2014:06:12 12:29:18-05:00
Format                          : application/pdf
Description                     : MD2 Valve
Title                           : 312185S - MD2 Valve, Instructions - Parts, English
Creator                         : Heath McCartney
Subject                         : 312185, MD2 Valve, 255179, 255180, 255181, 255182, 255206, 255208, 255249, 312185S, 312185EN, 312185EN-S, MM 312185
Document ID                     : uuid:a3f29ba7-2fc2-4b48-9d40-bb37c05b7a3d
Instance ID                     : uuid:5bf9ef27-23d7-4dd8-8cb2-7dbdd478e0f8
Page Count                      : 30
Author                          : Heath McCartney

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Graco 312185S Md2 Valve Users Manual Valve, Instructions Parts, English

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