PVA MV250 User manual

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MV250
POSITIVE DISPLACEMENT VALVE
Version: B12-3822
Operation Manual
Revision: A
January 2013

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This document is based on information available at the time of its publication. While efforts have been
made to be accurate, the information contained herein does not purport to cover all details or variations in
hardware or software, nor to provide for every possible contingency in connection with installation,
operation, or maintenance. Features may be described herein which are not present in all hardware and
software systems. Precision Valve & Automation, Inc. assumes no obligation of notice to holders of this
document with respect to changes subsequently made.
Precision Valve & Automation, Inc. makes no representation or warranty, expressed, implied, or statutory
with respect to, and assumes no responsibility for the accuracy, completeness, sufficiency, or usefulness of
the information contained herein. No warranties of merchantability or fitness for purpose shall apply.
This document, including the information contained herein, is the property of Precision Valve &
Automation, Inc. and is considered confidential and proprietary information. It is delivered on the express
condition that it not be used, disclosed, or reproduced in whole or in part, for any reason without prior
written consent of Precision Valve & Automation, Inc.
Copyright © 2010
Precision Valve & Automation, Inc.
All Rights Reserved.

3
Preface
MV250
Metering Valve, Positive Displacement Dispense Valve
Thank you for purchasing the MV250 dispensing valve from PVA. Before attempting to operate the
MV250, we recommend that you take a few minutes and read the following operation and setup manual.
This will assist in familiarizing you with the product and ensure a successful installation.
As always, if any questions or problems arise, do not hesitate to contact PVA’s Valve Service Department
for support. This department can be reached at PVA headquarters via telephone or e-mail.
Again, thank you for your purchase, and we look forward to assisting you in the future as you continue to
improve your dispensing processes.
PVA Contact Information
Main Office
Technical Support
Sales Support
PVA
Six Corporate Drive
Halfmoon, NY12065
Tel [phone]
Fax [phone]
Website http://www.pva.net
Email mailto: [email protected]
Tel [phone]
Email mailto: [email protected]
Tel [phone]
Email mailto: [email protected]

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Table of Contents
Preface............................................................................................................................................................ 3
MV250........................................................................................................................................................ 3
PVA Contact Information........................................................................................................................... 3
Table of Contents ........................................................................................................................................... 4
Table of Figures.............................................................................................................................................. 4
Theory of Operation....................................................................................................................................... 5
Air Section.................................................................................................................................................. 5
Fluid Section............................................................................................................................................... 5
Wetted parts on the MV250 include:...................................................................................................... 5
Safety.............................................................................................................................................................. 5
Setup............................................................................................................................................................... 5
Tool Kit .......................................................................................................................................................... 6
Operation........................................................................................................................................................ 7
Air Section.................................................................................................................................................. 7
Fluid Section............................................................................................................................................... 7
Additional Bleeding........................................................................................................................................ 7
Setting Dispense Volume ............................................................................................................................... 8
Periodic Maintenance..................................................................................................................................... 8
Routine Cleaning and Disassembly................................................................................................................ 8
Assembly Instructions ...................................................................................................................................10
General ......................................................................................................................................................10
Air Section.................................................................................................................................................10
Fluid Section..............................................................................................................................................10
Assemble Sections.....................................................................................................................................11
Setting Micrometer to Zero ...........................................................................................................................11
Micrometer Adjustment Breakdown .........................................................................................................12
Spare Parts.....................................................................................................................................................13
Bill of Materials for MV250:.....................................................................................................................16
Troubleshooting.............................................................................................................................................17
PVA Warranty Policy....................................................................................................................................18
Table of Figures
Figure 1: Solenoid Valve................................................................................................................................ 6
Figure 2: Tool Kit Contents............................................................................................................................ 6
Figure 3: Micrometer Adjustment Breakdown..............................................................................................12
Figure 4: Micrometer Section Key................................................................................................................12
Figure 5: Spare Parts Kit Contents ................................................................................................................13
Figure 6: Drawing 112-5826_1 .....................................................................................................................14
Figure 7: Drawing 112-5826_2 .....................................................................................................................14
Figure 8: Bill of Materials for Figure 6.........................................................................................................16

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Theory of Operation
The MV250 is a rod displacement style metering valve designed to dispense small volumes of fluid with
the highest degree of accuracy. This true positive displacement valve will dispense one small dot of fluid
with each full cycle. Fluid volume is determined by the micrometer adjustment setting and cannot be
affected by changes in fluid viscosity due to temperature or changes in fluid delivery pressure.
MV250 volumetric fluid displacement range:
(0.0001 cc – 0.012 cc)
The MV250 has a divorced design comprising of two major sections. These include:
•Air section (red anodized portion)
•Fluid section (stainless steel portion)
Air Section
The air section is an aluminum body with a simple piston/cylinder combination used to cycle the valve. A
micrometer adjustment in the upper air body controls how far the piston and needle assembly can retract
thus altering the volume of fluid that can be metered and dispensed during each cycle.
Fluid Section
The fluid section is a stainless steel body, which includes a needle, seat, and two integral check valves to
make up the metering chamber. The metering chamber fills as the needle retracts away from the seat, then
dispenses as the needle moves back toward the seat. Such fluids may include but are not limited to;
solvents, epoxies, UV adhesives, silicones, RTV, grease, etc.
The outlet adapter of the MV250 is designed to fit PVA’s Micro Dispense Nozzles.
Wetted parts on the MV250 include:
•303, 304 stainless steel
•Teflon®
•Kalrez®
Safety
Due to material contents being under pressure eye protection is required for operators. Refer to MSDS
sheets on material being dispensed for other precautions.
Setup
The MV250 requires a 2-position, 4-way air solenoid valve to actuate the air section. The valve should be
operated with clean, dry air between 60-100psi. Two #10-32 threaded air ports are located on the air section
of the valve. The port located closest to the mid-section of the valve is air actuating to fill the fluid
chamber. The port located furthest from the mid-section of the valve is air actuating to dispense material.
Quick connect air fittings are typically supplied with the MV250 to fit 5/32"od tubing. Note that the valve
should be normally in the closed & dispensed position.
Fluid is supplied to the MV250 through the 1/8"npt port located on the stainless steel fluid section of the
valve.

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Figure 1: Solenoid Valve
Tool Kit
PVA offers standard tool kits for all dispensing valves. The tool kit for the MV250 is part number
B12-1986, which includes all necessary tools and lubricating grease to perform maintenance on this
dispense valve.
Figure 2: Tool Kit Contents
Qty
Part Number
Description
2
0266244
8" Adjustable Wrench
2
26563
3/32" Hex Key
1
26561
5/64" Hex Key
1
26559
1/16” Hex Key
1
5516A18
Tweezers
1
B62-0752
Mineral Oil Lubrication Kit, 2.5cc
1
B62-2048
Silicone Lubricant for O-ring, 2.5cc
1
9570K71
Hook and Pick Set
1
0266255
Pliers
2
53085A61
Soft Plastic Covers for Pliers
1
PB135/2
Screw Driver for Micrometer
1
PT17184
Micrometer Adjustment Wrench
1
MM115
Removable Thread Locker

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Operation
Refer to assembly drawings 112-5826_2 and Figure: 3 for part reference numbers.
Air Section
•Plumb up the valve as outlined above in the Setup procedure.
•Regulate the air pressure operating the valve between 60-100psi.
•Making sure that the valve is not aimed toward anyone, cycle the valve several times.
Note: When the valve is cycling, the piston should be heard hitting the micrometer adjustment (10), and
the needle (1) should be seen going up and down in the center.
If the valve is not cycling properly, refer to the Troubleshooting section.
Fluid Section
•When the fluid delivery system is connected to the valve, pressurize the material to be dispensed
at 10 psi.
•To bleed the fluid section, use a 3/32" Hex key to loosen the set screw (19) of the bleed port
located on the fluid section (7), being careful not to fully remove the screw.
Note: If fluid does not flow out of the bleed port, slowly increase material pressure until fluid and air
bubbles are seen.
Note: Do not exceed 20psi for purging.
•Once material begins to flow steadily and all air bubbles have been bled, tighten the set screw (19)
and wipe the valve clean.
•Open the stroke on the valve to full by turning the micrometer adjustment (10) counter clockwise
until it reaches its furthest point, about #3 on the dial (D).
•If possible turn the valve vertical so the dispense tip is pointing up in the air. Note: Hold a cloth
over the dispense tip to catch fluid flow from the tip.
•Cycle the valve several times until material begins to dispense from the nozzle. Continue to cycle
the valve until all air bubbles cease to dispense from the tip and a steady flow of material can be
seen with each shot.
Note: If material is dispensing properly, Skip the Additional Bleeding section
Additional Bleeding
Entrapped air inside the fluid section and outlet check valve housing of this metering valve will greatly
reduce the repeatability of the dispense volumes or even prevent the valve from fully priming. Air bubbles
trapped in this chamber will compress thus altering the amount of fluid that can pass the outlet check valve
and dispense.
For additional bleeding, follow these steps:
•Remove fluid pressure from the valve.
•Apply air pressure to the air section of the valve to set the cylinder the in refill position, so the
needle (1) is retracted from the seat (9).

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•Using an adjustable wrench, unthread and remove the outlet check valve housing (8) from the
fluid section (7).
•Holding the outlet check valve housing (8) upright with tip down, fill the well of this housing with
the fluid that is being dispensed. (A compatible solvent can also be used)
•Keeping the outlet check valve housing (8) in the upright position, thread the assembly back onto
the fluid section (7) and tighten with an adjustable wrench.
•Again pressurize the material to be dispensed between at about 10 psi.
•If possible turn the valve vertical so the dispense tip is pointing up in the air. Note: Hold a cloth
over the dispense tip to catch fluid flow from the tip.
•Once again cycle the valve several times until the fluid can be seen dispensing from the tip with
some force behind it.
Setting Dispense Volume
•Once all air is eliminated from the metering chamber, the micrometer adjustment (10) can be used
to set a specific shot volume to be dispensed each cycle.
•Turning the micrometer adjustment (10) clockwise will decrease the volume of material in each
shot, and turning it counter-clockwise will increase the volume of material in each shot.
Note: If the micrometer adjustment is turned all the way down it will not allow fluid to be dispensed.
•Once the micrometer adjustment (10) setting is determined, the collar (E) can be turned clockwise
to lock the setting in place.
Note: Refer to Troubleshooting section for any problems.
Periodic Maintenance
Refer to the MV250 cross sectional view for location of parts referenced in the following procedures.
•Lubricate the packing (5) and o-ring (24) on the MV250 valve every ~200 hrs by placing a few
drops of mineral oil or other light oil inside the packing nut (4).
Note: PVA offers a 2.5cc mineral oil lubrication kit; Part#: B62-0752.
•The packing nut (4) may require occasional tightening, as wear occurs in order to prevent leaks
through the packing.
Routine Cleaning and Disassembly
Cleaning and rebuilding the valve will be required from time to time. A spare parts kit, part # MV250-SP is
available with all the normal wear parts included.
•Begin disassembly by removing air and fluid pressure from the valve.
•Remove all pneumatic tubing and fluid delivery fittings, hoses, etc. from the valve.

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•Using the tip of a 3/32" Hex key, loosen the packing nut (4).
•Using the same 3/32" Hex key, evenly remove the two machine screws (17) that thread into the
fluid body standoffs (7).
Note: During removal that there is a spring (11) forcing the air section away from the fluid section.
•Pull the air section (red anodized portion) away from the fluid section (stainless steel portion).
•Clean off the tip of the stainless steel needle (1).
•From the fluid section of the valve, unthread and remove the packing nut (4), followed by the
packing (5) and o-ring (24).
•Unthread and remove the nozzle lock nut (3) from the outlet check valve housing (8) then remove
the dispense nozzle (15) from the lock nut.
•Using an adjustable wrench, unthread and remove the outlet check valve housing (8) from the
fluid section (7).
•Use pliers pull the seat (9) out of the fluid section (7) and remove the 006 Kalrez®O-ring (25)
from the seat.
Note: If stuck, the seat can be pushed through from the opposite side of the fluid section.
•Using an adjustable wrench, unthread and remove the inlet check valve housing (6) from the fluid
section (7) and remove the 007 Kalrez®O-ring (27) from the housing.
•With a standard 3/32” Hex Key, remove the bleeder set screws (19) from the fluid section (7).
•Submerge the inlet and outlet check valve housings (6, 8) in solvent.
•Clean all other wetted parts thoroughly with an appropriate solvent.
•On the air section, use a standard 3/32" Hex Key to evenly remove the final two machine screws
(16) that thread into the end cap (20).
Note: During removal that the spring (11) will force the air section apart.
•Separate the upper air body (2) from the lower air body (21) to remove the spring (11) then slide
the end cap (20) off of the needle (1).
•Holding the lower air body (21) in one hand, grab the needle (1) then push the needle and piston
(22) assembly out of the lower air body.
•Remove the 004 Buna O-ring (23) from the lower air body (21).
•Hold the piston (22) with an adjustable wrench then use a 5/64" Hex key to unthread and remove
the set screw (18) to remove the needle(1) then remove the 014 Buna O-ring (28) from the piston.
•Remove the 014 Buna O-ring (28) from the upper air body (2).
•Using a 1/16” Hex Key loosen but do not remove the set screw (12) that secures the micrometer
adjustment (10) to the upper air body (2).
•Using soft tip pliers grip the collar (E) or midsection (D) of the micrometer adjustment (10) and
turn counter-clockwise to loosen then unthread and remove from the upper air body (2) by hand.
•Remove the 007 Buna O-ring (26) from the micrometer adjustment (10).
Replace components with spares provided in the spare parts kit.

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Assembly Instructions
General
•All O-rings must be lubricated with a small amount of silicone grease.
Note: PVA offers a 2.5cc silicon o-ring lubrication kit; Part#: B62-2048.
•A small amount of removable thread locker should be applied to the set screw (18).
•Assemble the air section and fluid section separately prior to connecting the two pieces.
Air Section
•Mount one 007 Buna O-ring (26) on the end (F) of the micrometer (10) and slide it up to the
threads.
•Thread the micrometer (10) into the upper air body (2) hand tight.
•Holding the collar (E) of the micrometer (10) turn the dial (C) counter-clockwise until the number
5 can be seen on the midsection (D).
•Using soft tip pliers grab the midsection (D) section of the micrometer (10) and turn clockwise to
snug it onto the upper air body (2).
•Thread the set screw (12) into the upper air body (2) and tighten with a 1/16” Hex Key.
•Mount one 014 Buna O-ring (28) on the end of the upper air body (2).
•Drop the needle (1) into the piston (22) and assemble with the set screw (18) using an adjustable
wrench and 5/64" Hex key to tighten.
•Mount the other 014 Buna O-ring (28) onto the piston (22).
•Apply a small amount of silicone grease to the inside of the lower air body (21) then drop in the
piston and needle assembly.
•Mount the 004 Buna O-ring (23) on the end of the needle (1) and slide it down into the groove in
the end of the lower air body (21).
•Slide the end cap (20) onto the needle up to the lower air body (21), place the spring (11) on top of
the piston (22), and assemble the two air bodies using two machine screws (16) tightening with a
3/32" Hex key.
Note: Be sure the air holes are lined up on the same face and will align with the fluid inlet check valve
housing (6).
Fluid Section
•Place the 004 Kalrez®O-ring (24) into the groove of the packing (5).
•Insert the packing (5) into the fluid section (7), cone side first with the o-ring (24) facing outward,
and screw in the packing nut (4) but leave finger tight until assembled with the air section.
•Mount the 006 Kalrez®O-ring (25) on the seat (9) and push the seat into the bottom of the fluid
section (7), cone side first. When inserting the seat, work the O-ring into the fluid body with finger
to prevent shearing of the edge of the O-ring.

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•Thread the outlet check valve housing (8) onto the bottom of the fluid section (7) and tighten with
an adjustable wrench.
•Place the 007 Kalrez®O-ring (27) into the groove of the inlet check valve housing (6).
•Thread the inlet check valve housing (6) into the side of the fluid section (7) and tighten with an
adjustable wrench.
•Drop the micro dispense nozzle (15) into the nozzle lock nut (3) then thread the lock nut onto the
outlet check valve housing (8).
•Thread the set screws (19) into the fluid section (7) and tighten using a 3/32" Hex key.
Assemble Sections
•Be sure the micrometer adjustment (10) is backed out far enough so at least the number 1 can be
seen on the midsection (D).
•Apply a small amount of silicone grease to the end of the needle (1) then insert it into the packing
nut (4) and slide the two sections together.
•Align the air holes of the air section on the same face as the fluid inlet check valve (6) then
connect the sections using the two machine screws (17) tightening them down evenly using a
3/32" Hex key.
•Using the tip of a 3/32" Hex key, tighten the packing nut (4).
Setting Micrometer to Zero
When assembling the valve it will be necessary to re-calibrate the micrometer adjust back to the zero
position.
•Using the wrench (A), insert the inside tip of the small end into the orifice of the midsection (D)
and rotate it clockwise until the numbered centerline is on a side that can most easily be viewed by
the operator.
Note: Valves are supplied from the factory with the center line located on the same face of the fluid inlet.
•Turn the dial (C) clockwise until the end (F) hits the piston (10).
•Using soft tip pliers, hold the knurled end of the dial (C) tightly and loosen the screw (B) using a
flat head screw driver.
Note: Loosen the screw 3-4 turns only. It is not necessary to fully remove the screw.
•Using a soft dead blow hammer, tap the dial (C) of the micrometer adjust to unlock it from the
mid section (D). The dial will now spin freely.
•Rotate the dial (C) to align the zero mark of the dial with the numbered centerline of the
midsection (D) and press down firmly to secure the dial in place.
•Hold the dial (C) securely in one hand maintaining alignment with the zero mark and numbered
centerline, then carefully tighten the screw (B) using the flat head screw driver to lock the
micrometer adjustment.

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Micrometer Adjustment Breakdown
Figure 3: Micrometer Adjustment Breakdown
Reference
Letter
Section Description
A
Micrometer Wrench
B
Top Screw
C
Dial
D
Micrometer Midsection
E
Collar
F
Micrometer End
Figure 4: Micrometer Section Key

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Spare Parts
PVA offers standard spare parts kits for all dispensing valves. These kits are stocked for immediate
shipment and allow replacement of all wearable parts of the valve.
The spare parts kit for this valve, product number MV25-SP, includes the following components:
MV25-SP Includes:
Figure 5: Spare Parts Kit Contents
Qty
Part Number
Description
1
114-4750
Needle
1
214-6507
Seat
1
214-3441
Packing w/o-ring groove
1
VLV-004B
004 Buna O-ring
1
VLV-004K
004 Kalrez®O-ring
1
VLV-006K
006 Kalrez®O-ring
1
VLV-007B
007 Buna O-ring
1
VLV-007K
007 Kalrez®O-ring
2
VLV-014B
014 Buna O-ring

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Figure 6: Drawing 112-5826_1

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Figure 7: Drawing 112-5826_2

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Bill of Materials for MV250:
Version: B12-3822
Figure 8: Bill of Materials for Figure 7
Item
Part Number
Description
Quantity
1
114-4750
Needle
1
2
114-6556
Upper Air Body
1
3
114-8274
Nozzle Lock Nut
1
4
114-9206
Packing Nut
1
5
214-3441
Packing w/ O-ring Groove
1
6
214-6176
Check Valve Body, Inlet
1
7
214-6180
Fluid Body
1
8
214-6212
Check Valve Body, Outlet
1
9
214-6507
Seat
1
10
01423
Micrometer Adjustment
1
11
01344
Spring
1
12
01469
Set Screw
1
13
02367
Check Valve, Inlet
1
14
02368
Check Valve, Outlet
1
15
* TBD
Micro Dispense Nozzle
1
16
SH5-40x1.75
Socket Head Cap Screw
2
17
SH5-40x2.0
Socket Head Cap Screw
2
18
V001
Set Screw
1
19
V007
Bleeder Plug
2
20
V200
End Cap
1
21
V201
Lower Air body
1
22
V202
Piston
1
23
VLV-004B
004 Buna O-ring
1
24
VLV-004K
004 Kalrez®O-ring
1
25
VLV-006K
006 Kalrez®O-ring
1
26
VLV-007B
007 Buna O-ring
1
27
VLV-007K
007 Kalrez®O-ring
1
28
VLV-014B
014 Buna O-ring
2
* Refer to PVA’s data sheet on Micro Dispense Nozzles for a list of available nozzle options.

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Troubleshooting
Problem
Possible Cause
Corrective Action
Valve does not
cycle
Air pressure to air section too low
Packing nut is too tight
Micrometer adjustment is bottomed out
Material is cured in the valve
Valve was assembled without lubricating
the O-ring seals
Increase air pressure to 60-100 psi
Loosen packing nut until valve just begins to
cycle, retighten
Back out micrometer adjustment by turning it
counter-clockwise
Disassemble and clean valve
Disassemble valve, lubricate seals and re-
assemble
Material leaks from
valve tip
Packing nut is too tight
Air bubble trapped in fluid body, needle
adapter, or dispense needle
Check valve is worn
Loosen packing nut
Flip valve upside down and cycle until air
bubbles are removed, or loosen set screw on
fluid body to bleed air
Replace parts as necessary
Valve leaks from
mid-section
Packing nut is loose
Packing is worn
O-Ring is worn
Tighten packing nut until snug
Replace packing
Replace o-Ring
Valve does not
dispense anything
Air trapped in fluid body, needle adapter,
or dispense needle
Valve is not cycling
Fluid pressure is too low
Material cured in fluid section
Micrometer adjustment set too low
Flip valve upside down and cycle until air
bubbles are removed, or loosen set screw on
fluid body to bleed air
See above
Increase fluid pressure
Disassemble and clean valve
Back out micrometer adjustment by turning it
counter-clockwise
Air bubbles in fluid
Valve not properly purged
Problem with fluid delivery system
Flip valve upside down and cycle until air
bubbles are removed, or loosen set screw on
fluid body to bleed air
Diagnose and repair.
Inconsistent shot
sizes
Improper material viscosity
Air trapped in material being dispensed
No solution
Flip valve upside down and cycle until air
bubbles are removed, or loosen set screw on
fluid body to bleed air

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PVA Warranty Policy
PVA warrants the enclosed product against defects in material or workmanship on all components for one
year from the date of shipment.
The warranty does not extend to components damaged due to misuse, negligence, or installation and
operation that are not in accordance with the recommended factory instructions. Unauthorized repair or
modification of the enclosed product, and/or the use of spare parts not directly obtained from PVA (or from
factory authorized dealers) will void all warranties.
All PVA warranties extend only to the original purchaser. Third party warranty claims will not be honored
at any time.
Prior to returning a product for a warranty claim, a return authorization must be obtained from PVA’s
customer service department. Authorization will be issued either via the telephone, facsimile, or in writing
upon your request.
To qualify as a valid warranty claim, the defective product must be returned to the factory during the
warranty period. Upon return, PVA will repair (or replace) all components found to be defective in
material or workmanship.
(Retain this for your records)
Product Information:
PRODUCT: ______________________________
SERIAL NUMBER: ______________________________
DATE OF PURCHASE: ______________________________