Agilent Technologies VPI401205060, VPI252205060, VPI251205060, VPI401335060, VPI402665060 Instruction Manual

Vacuum Products Division

Vacuum Pump

Isolation (VPI) Valve

INSTRUCTION MANUAL

Manual No. 699912117
Revision F
December 2012

Vacuum Pump Isolation (VPI) Valve

Vacuum Pump

Isolation (VPI) Valve

Dust-Off is a registered trademark of Falcon Safety Products, Inc.
Krytox is a registered trademarks of DuPont.
TriScroll is a trademark of Agilent, Inc.
Viton is a registered trademark of DuPont Dow Elastomers.
Apiezon L is a registered trademark of M & I Materials.

Copyright 2012

Agilent, Inc.

Vacuum Pump Isolation (VPI) Valve

Contents

Warranty ............................................................................................................................................ 9

Warranty Replacement and Adjustment ...................................................................................... 9

Hazard and Safety Information .................................................................................................. 10

Contacting Agilent ......................................................................................................................11

Section 1. Introduction ..................................................................................................................... 13

1.1 Description ........................................................................................................................... 13

1.2 Operating Principles..............................................................................................................13

1.3 Operation Sequence............................................................................................................. 14

1.4 Technical Specifications ....................................................................................................... 16

Section 2. Installation .......................................................................................................................17

2.1 Electrical .............................................................................................................................. 17

2.2 Installing VPI Valve to Agilent TriScroll™ Vacuum Pump..................................................... 18

2.2.1 TriScroll 300, 320, 600, and 620.................................................................................. 18

2.2.2 Wiring........................................................................................................................... 18

2.2.3 TriScroll 300, 600 Inverter............................................................................................ 20

2.3 Mechanical............................................................................................................................22

Section 3. Service ............................................................................................................................ 23

3.1 Disassembly .........................................................................................................................23

3.2 Repair of Sub-Assemblies .................................................................................................... 24

3.2.1 Piston/Diaphragm Sub-Assembly ................................................................................24

3.2.2 Nose Piece O-ring Replacement.................................................................................. 25

3.3 Reassembly .......................................................................................................................... 26

3.4 Troubleshooting.................................................................................................................... 27

3.4.1 VPI Valve Cannot Be Pumped Down to High Vacuum ................................................27

3.4.2 VPI Valve Leaks in Closed Position.............................................................................27

3.4.3 VPI Valve Closes Too Slowly....................................................................................... 28

3.4.4 VPI Valve Opens Too Slowly or Not Completely .........................................................28

3.4.5 VPI Valve Fails to Open...............................................................................................28

3.4.6 Closing Causes Large Burst of Air into System ...........................................................28

3.4.7 Solenoid Valve is Hot...................................................................................................29

3.5 Factory Repair ...................................................................................................................... 30

3.6 Replacement Parts ............................................................................................................... 31

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Vacuum Pump Isolation (VPI) Valve

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Vacuum Pump Isolation (VPI) Valve

Figures

1 Operating Sequence............................................................................................................14

2 Single Phase Motor Electrical Connections......................................................................... 19

3 Three Phase Motor Electrical Connections.......................................................................... 19

4 VPI Application in TriScroll 300, 600 Inverter Pumps ..........................................................20

5 Installation Diagram.............................................................................................................22

6 Assembly View and Replacement Parts.............................................................................. 23

7 Assembly View and Replacement Parts.............................................................................. 26

5

Vacuum Pump Isolation (VPI) Valve

6

Vacuum Pump Isolation (VPI) Valve

Tables

1 Technical Specifications ..................................................................................................... 16

2 Operating Voltages............................................................................................................. 17

3 VPI Valve Installation Data ................................................................................................. 18

4 Replacement Parts/Kits ...................................................................................................... 31

7

Vacuum Pump Isolation (VPI) Valve

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Vacuum Pump Isolation (VPI) Valve

Warranty

Products manufactured by Seller are warranted against defects in materials and workmanship for twelve
(12) months from date of shipment thereof to Customer, and Seller’s liability under valid warranty
claims is limited, at the option of Seller, to repair, to replace, or refund of an equitable portion of the
purchase price of the Product. Items expendable in normal use are not covered by this warranty. All
warranty replacement or repair of parts shall be limited to equipment malfunctions which, in the sole
opinion of Seller, are due or traceable to defects in original materials or workmanship. All obligations of
Seller under this warranty shall cease in the event of abuse, accident, alteration, misuse, or neglect of
the equipment. In-warranty repaired or replaced parts are warranted only for the remaining unexpired
portion of the original warranty period applicable to the repaired or replaced parts. After expiration of
the applicable warranty period, Customer shall be charged at the then current prices for parts, labor,
and transportation.

Reasonable care must be used to avoid hazards. Seller expressly disclaims responsibility for loss or
damage caused by use of its Products other than in accordance with proper operating procedures.

Except as stated herein, Seller makes no warranty, express or implied (either in fact or by operation of
law), statutory or otherwise; and, except as stated herein, Seller shall have no liability under any war­ranty, express or implied (either in fact or by operation of law), statutory or otherwise. Statements made
by any person, including representatives of Seller, which are inconsistent or in conflict with the terms of
this warranty shall not be binding upon Seller unless reduced to writing and approved by an officer of
Seller.

Warranty Replacement and Adjustment

All claims under warranty must be made promptly after occurrence of circumstances giving rise thereto,
and must be received within the applicable warranty period by Seller or its authorized representative.
Such claims should include the Product serial number, the date of shipment, and a full description of
the circumstances giving rise to the claim. Before any Products are returned for repair and/or adjust­ment, written authorization from Seller or its authorized representative for the return and instructions as
to how and where these Products should be returned must be obtained. Any Product returned to Seller
for examination shall be prepaid via the means of transportation indicated as acceptable by Seller.
Seller reserves the right to reject any warranty claim not promptly reported and any warranty claim on
any item that has been altered or has been returned by non-acceptable means of transportation. When
any Product is returned for examination and inspection, or for any other reason, Customer shall be
responsible for all damage resulting from improper packing or handling, and for loss in transit, notwith­standing any defect or non-conformity in the Product. In all cases, Seller has the sole responsibility for
determining the cause and nature of failure, and Seller’s determination with regard thereto shall be
final.

If it is found that Seller’s Product has been returned without cause and is still serviceable, Customer will
be notified and the Product returned at its expense; in addition, a charge for testing and examination
may be made on Products so returned.

3/1/00

9

Vacuum Pump Isolation (VPI) Valve

Hazard and Safety Information

This manual uses the following standard safety protocols:

WARNING

CAUTION

NOTE

Operators and service personnel must be aware of all hazards associated with this
equipment. They must know how to recognize hazardous and potentially hazardous
conditions, and know how to avoid them. The consequences of unskilled, improper, or
careless operation of the equipment can be serious. This product must only be operated and
maintained by trained personnel. Every operator or service person must read and
thoroughly understand operation/maintenance manuals and any additional information
provided by Agilent, Inc. All warning and cautions should be read carefully and strictly
observed. Consult local, state, and national agencies regarding specific requirements and
regulations. Address any safety, operation, and/or maintenance questions to your nearest
Agilent, Inc. office.

The warning messages are for attracting the attention of the
operator to a particular procedure or practice which, if not
followed correctly, could lead to serious injury.

The caution messages are displayed before procedures, which
if not followed, could cause damage to the equipment.

The notes contain important information.

Vacuum Equipment and Cleanliness

Cleanliness is vital when servicing any vacuum equipment.

CAUTION

NOTE

10

Do not use silicone oil or silicone grease.

Use powder-free butyl or polycarbonate gloves to prevent
skin oils from getting on vacuum surfaces.

Do not clean any aluminum parts with Alconox®. Alconox
is not compatible with aluminum and will cause damage.

Normally, it is unnecessary to use vacuum grease.
However, if it must be used, avoid silicone types, and
use it sparingly. Apiezon®L grease is recommended
(Agilent Part Number 695400004).

O-ring Care

When removing, checking or replacing O-rings, keep in mind the following:

Vacuum Pump Isolation (VPI) Valve

NOTE

CAUTION

Contacting Agilent

Agilent recommends replacing all O-rings during routine
maintenance or during any maintenance procedure requiring
that O-rings be removed.

Remove O-rings carefully with your fingers. Do not use metal
tools for this task. This prevents scratching of any sealing
surfaces.

❑

Wipe all O-rings clean with a lint-free cloth before
installation to ensure that no foreign matter is present to
impair the seal.

❑

Do not use alcohol, methanol or other solvents on O-rings.
To do so causes deterioration and reduces their ability to
hold a vacuum.

❑

If applicable, apply a small amount of Apiezon®L grease
and wipe the O-rings “shiny” dry.

In the United States, you can contact Agilent Customer Service at 1-800-882-7426. See the
back cover of this manual for a listing of our sales and service offices.

Visit our web site at:
http://www.chem.agilent.com/en-US/Products/Instruments/vacuum/pages/default.aspx.

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Vacuum Pump Isolation (VPI) Valve

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Vacuum Pump Isolation (VPI) Valve

Section 1. Introduction

1.1 Description

The Vacuum Pump Isolation (VPI) valve is a safety valve that protects a vacuum system
in the event of power failure by isolating the vacuum system and venting the mechanical
pump. This avoids oil back up and allows the motor to restart the pump more easily. The
VPI valve is offered with the ISO-KF flange sizes and solenoid voltages/frequencies most
commonly found on mechanical pumps. Since it operates with atmospheric pressure and
activates upon loss of electrical power, the novel design requires no external pressurized
gas source.

The fast acting VPI valve is light weight, constructed of vacuum compatible materials, and
maximizes pumping conductance. Lifetimes in excess of 100,000 cycles are typical, which
translates into years of trouble free use in suitable environments. The opening burst is less
than the critical backing pressure for turbomolecular and diffusion pumps, when
appropriately sized mechanical pumps are used. The closing burst is minimized by the
unique patented buffer volume design.

The VPI valve consumes little power. Installation is simple because standard ISO-KF
dimensions are used, allowing the valve to replace elbows, tees, and crosses of the same
size. Even when the mechanical pump is equipped with an integral anti-suckback valve, a
VPI valve should be used because the pump’s integral valve will not vent it.

1.2 Operating Principles

The VPI valve’s solenoid valve is connected in parallel with the mechanical pump’s
electrical supply, either at its source or at the pump’s switch. When the electrical power is
on, the solenoid valve is closed, allowing the pump to keep the VPI valve’s body and the
vacuum system evacuated. Interruption of electrical power to the mechanical pump causes
the solenoid valve to open. Air is admitted into the VPI valve causing it to close very
quickly. This isolates the vacuum system from the mechanical pump, while the pressure
differential between the outside atmosphere and the vacuum system provides the force to
maintain the valve in its closed position without electrical or pneumatic power. With the
vacuum system isolated, a series of small orifices admits air to the inlet port of the
mechanical pump until it has risen to atmospheric pressure. When the mechanical pump is
restarted, it evacuates the area above the piston until the pressure is lowered to
approximately that of the vacuum system. The VPI valve automatically opens again
allowing the vacuum system to be pumped at the full speed of the mechanical pump.

13

Vacuum Pump Isolation (VPI) Valve

1.3 Operation Sequence

14

Figure 1 Operating Sequence

Vacuum Pump Isolation (VPI) Valve

Figure 1 (a): Normal Operation – Open Position Power is on to the mechanical pump and
the VPI valve. The mechanical pump, inlet side of the VPI valve, and the VPI valve are all
under vacuum at approximately the same pressure. The spring is holding the VPI valve
open, and the vacuum system is exposed to the mechanical pump’s full pumping speed.

Figure 1 (b): Power Interruption The VPI valve solenoid loses its power, since it is
connected in parallel to the mechanical pump. The solenoid opens to the atmosphere. Air
enters the VPI valve through the solenoid and creates a higher pressure above the piston
than exists below it. The piston closes rapidly (30 ms). During this time only the inside of
the piston (buffer volume) is being filled, isolating the vacuum system from any introduction
of air. This figure shows the piston in transit downward.

Figure 1 (c): Valve Closed – Mechanical Pump Vented The piston is fully down and the
VPI valve is fully closed. The higher pressure above the piston forces it against the valve
seat, where the Viton® O-ring makes a vacuum tight seal. Air from the higher pressure area
above the piston continues to flow through the small orifice in the top of the piston into the
inside of the piston, and through a second small orifice in its side into the mechanical
pump’s inlet port. This vents the mechanical pump to atmospheric pressure gradually.
When the pump is fully vented, the pressure above the piston, inside the piston, and in the
mechanical pump are the same (atmospheric). The pressure below the piston, in the
vacuum system, is still lower and the piston remains down (closed), maintaining the
vacuum system under vacuum.

NOTE

Given enough time, the pressure in the vacuum system will rise
due to outgassing, leaks, etc., or venting by the operator, and
when the pressure is high enough, the spring will open the
piston and the vacuum system will be at the same pressure as
the mechanical pump (atmospheric).

Figure 1 (d): Power Restored The solenoid coil is energized causing the solenoid to close,
isolating the inside of the VPI valve from the outside atmosphere. The mechanical pump
evacuates the inside of the piston through the small orifice in its side and the area above the
piston through the small orifice in the top of the piston via the inside of the piston. When the
pressure above the piston is approximately equal to that in the vacuum system, the spring
pushes the piston upward, fully opening the VPI valve. The vacuum system is now back in
normal operation and exposed to the full pumping speed of the mechanical pump.

NOTE

In Figure 1, the mechanical pump is connected to the port on
the right side and the vacuum system to the bottom port.

15

Vacuum Pump Isolation (VPI) Valve

1.4 Technical Specifications

Table 1 Technical Specifications

Nominal body ID 2 in. (50 mm)
Leak rate

❑ Body
❑ Seal

Closing time 30 milliseconds
Closing burst 1 x 10
Power 7.0 Watts for AC applications

Materials

❑ Body and flanges
❑ Piston
❑ Seals (O-ring and diaphragm)
❑ Guide pin

Temperature range (valve) 0° to 100° C
Temperature range (solenoid) 0° to 50° C
Venting time

❑ NW40

<1 x 10-9 atm cc/sec He
<1 x 10-9 atm cc/sec He

-2

Torr-liter

5.8 Watts for TriScroll inverter pump
applications

Extruded aluminum (6061 -T6)
Machined aluminum (2024)
Viton
304 stainless steel

10 s/ι of vented volume

16

❑ NW25

50 s/ι of vented volume

Vacuum Pump Isolation (VPI) Valve

Section 2. Installation

2.1 Electrical

The VPI Valve should be installed so that it is controlled by the vacuum pump’s electrical
source, preferably at the vacuum pump’s automatic or manual switch. Ideally the opening
of the valve should occur simultaneously with or after the pump start up. The valve closing
should occur simultaneously or prior to the pump shut off.

Refer to Table 2 to verify that the solenoid operating voltage range of the VPI Valve to be
installed is compatible with the actual operating voltage and frequency that will be used to
control the VPI Valve. Verify that the valve is properly grounded prior to applying electrical
power.

NOTE

The VPI Valve can be damaged if it is energized with a voltage
that is outside of it’s specified range.

Table 2 Operating Voltages

NW25

VPI Valve

Part Number

VPI251205060 VPI401205060 90-132 VAC 50/60 Hz 65 mA
VPI251335060 VPI401335060 120-146 VAC 50/60 Hz 22mA
VPI252205060 VPI402205060 180-264 VAC 50/60 Hz 32 mA
VPI252665060 VPI402665060 239-293 VAC 50/60 Hz 23 mA
VPI25INV24DC VPI40INV24DC 21.6-26.4 VDC 267mA

NW40

VPI Valve

Part Number

Solenoid Operating

Voltage Range

Maximum

Operating Current

17

Vacuum Pump Isolation (VPI) Valve

2.2 Installing VPI Valve to Agilent TriScroll™ Vacuum Pump

2.2.1 TriScroll 300, 320, 600, and 620

When installed correctly, the position of the VPI Valve is controlled by the TriScroll vacuum
pump motor internal thermal switch and it’s electrical supply. The VPI Valve will open
when the pump is running and close when it is stopped. It will also close if the TriScroll
motor thermal overload protection switch shuts down the pump.

2.2.2 Wiring

Refer to Table 3 to verify that the VPI Valve to be installed is compatible with the TriScroll
Vacuum Pump supply voltage and frequency. Then, find the proper wiring diagram to use
from Table 3. Remove the pump motor cover and connect the VPI Valve solenoid wire leads
to the pump motor as shown in the diagram. Replace the pump motor cover, and verify that
the valve is properly grounded prior to applying electrical power.

TriScroll

Vacuum Pump

Operating Voltage

100-120 VAC
50/60 Hz
1 Phase

NOTE

To prevent damage to the VPI Valve it must be installed only as
specified below.

Table 3 VPI Valve Installation Data

NW25

VPI Valve

Part Number

VPI251205060 VPI401205060 90-132 VAC

NW40

VPI Valve

Part Number

Solenoid

Operating

Voltage Range

50/60 Hz

Wiring Diagram

Location

Figure 2 on page 19
Low Voltage

200-230 VAC
50/60 Hz
1 Phase

200 VAC
50/60 Hz
3 Phase

230 VAC
50/60 Hz
3 Phase

380 VAC
50/60 Hz
3 Phase

18

VPI251205060 VPI401205060 90-132 VAC

50/60 Hz *

VPI251205060 VPI401205060 90-132 VAC

50/60 Hz *

VPI251335060 VPI401335060 120-146 VAC

50/60 Hz *

VPI252205060 VPI402205060 180-264 VAC

50/60 Hz *

Figure 2 on page 19
High Voltage

Figure 3 on page 19
Low Voltage

Figure 3 on page 19
Low Voltage

Figure 3 on page 19
High Voltage

Vacuum Pump Isolation (VPI) Valve

Violet

Black (TS300)

L2 (Line)

VPI Valve

L1 (Line)

L2

4

L1

3

Black (TS300)

L2 (Line)

VPI Valve

L1 (Line)

L2

4

L1

3

Violet

Blue (TS600)

VPI Valve

High Voltage Low Voltage

VPI Valve

Blue (TS600)

Red

Brown

Orange

White

Yellow

Blue

L1 (Line)

VPI Valve

L2 (Line)

L3 (Line)

High Voltage

Low Voltage

Brown

VPI Valve

Orange

Yellow

Red

VPI Valve

L1 (Line)

White

L2 (Line)
Blue

L3 (Line)

VPI Valve

Table 3 VPI Valve Installation Data (Continued)

TriScroll

Vacuum Pump

Operating Voltage

415 VAC
50/60 Hz

NW25

VPI Valve

Part Number

NW40

VPI Valve

Part Number

Solenoid

Operating

Voltage Range

VPI252205060 VPI402205060 180-264 VAC

50/60 Hz *

Wiring Diagram

Location

Figure 3 on page 19
High Voltage

3 Phase
460V 50/60 Hz

3 Phase

*Solenoid operating voltages are lower than the TriScroll vacuum pump operating voltages in order to utilize the TriScroll
motor’s internal thermal switch to actuate the VPI Valve.

VPI252665060 VPI402665060 239-293 VAC

50/60 Hz *

Figure 3 on page 19
High Voltage

Figure 2 Single Phase Motor Electrical Connections

Figure 3 Three Phase Motor Electrical Connections

19

Vacuum Pump Isolation (VPI) Valve

P1

Communication
Cable

VPI Valve

Mains Power Input

Splitter Cord

24 VDC

Power Supply

2.2.3 TriScroll 300, 600 Inverter

For TriScroll 300/600 Inverter models (Figure 4), a 24 VDC VPI kit (VPI25INV24DC for
triScroll 300/VPI40INV24DC for TriScroll 600), includes a VPI valve, a communication
cable, a 24 VDC power supply, and a splitter cord. The VPI valve is controlled by an output
signal from the inverter that is tied to motor operation.

Figure 4 VPI Application in TriScroll 300, 600 Inverter Pumps

NOTE

The VPI valve kit provided must be connected to I/O P1 before
starting the pump and operating the VPI valve. To prevent
damage to the valve, it must be installed only as specified
below.

20

Vacuum Pump Isolation (VPI) Valve

To install:

1. Connect the 24 VDC power supply and the pump inverter to the mains power using the
splitter cord.

2. Connect the communication cable DB9 connector into the inverter I/O port (P1).

3. Connect the 24 VDC power supply output cord to the communications cable labeled
24 V.

4. Connect the VPI solenoid cord to the communications cable connector labeled VPI.

21

2.3 Mechanical

The VPI valve is installed between the mechanical pump and vacuum chamber or high
vacuum pump (Figure 5). The flow arrows on the unit’s label point from the vacuum system
to the mechanical pump.

Vacuum Pump Isolation (VPI) Valve

Figure 5 Installation Diagram

While it is preferable to mount it directly onto the mechanical pump, it may be located
remotely. For best performance, the maximum volume should be on the vacuum system
side, and the minimum volume on the mechanical pump side of the VPI valve. Operation is
position independent and standard ISO-KF centering ring assemblies and clamps are used to
connect the VPI valve. The valve body can operate in ambient temperatures up to 100° C,
but the solenoid is limited to about 50° C because of the heat generated by the coil. This
should be kept in mind when selecting a mounting location.

The body of the VPI valve is very rugged, and it is difficult to deform it in any normal piping
arrangement used in vacuum systems. It is possible, however, that tremendous forces could
result from thermal expansion or from a long run of pipe cantilevered from a fixed valve.
Where this possibility exists, provide stress relief for the valve by installing a short bellows
and support the attached piping other than with the valve.

Valves are shipped with plastic snap-on covers over the ports to protect the delicate seal
surfaces and to keep the valve clean. These covers should be left in place until the moment
when the valve is to be installed in the piping. A single fiber or bit of lint on an O-ring seal
is enough to prevent leak-tight sealing. The usual cleaning techniques in vacuum practice
should be observed in installing the valve.

When installing the valve, adequate clearance should be allowed between adjacent
components so there is no sliding of seal surfaces against each other. Flanges that have been
assembled for some time may stick together. They should be separated gently.

22

CAUTION

Don’t set the valve down on unprotected seal surfaces.

Vacuum Pump Isolation (VPI) Valve

P1

Communication
Cable

VPI Valve

Mains Power Input

Splitter Cord

24 VDC

Power Supply

Section 3. Service

Vacuum components must be kept free of both particulate contamination and all foreign
materials which have a significant vapor pressure. Before repairing a vacuum valve, prepare
a clean dust-free work area and use clean, degreased tools devoted to precision assembly.

NOTE

3.1 Disassembly

The VPI valve should be periodically tested for proper
operation.

Figure 6 Assembly View and Replacement Parts

These instructions refer to Figure 6. Circled items are replacement parts. Items 1 through 4
are part of the Piston Assembly (see Section 3.6 “Replacement Parts” on page 31).

1. Remove the six 10-32 x 7/8 socket head cap screws from the bonnet.

2. Remove the bonnet with the solenoid valve still attached.

3. Remove the diaphragm/piston assembly by gently prying up the diaphragm at one edge
and pulling free of the body around the full circumference. Inspect the diaphragm for
holes, tears, or accumulated contamination and the orifices and for blockage.

23

Vacuum Pump Isolation (VPI) Valve

4. Inspect the nose piece ➄ O-ring carefully. It must be replaced if it is scratched or
imbedded with foreign material

3.2 Repair of Sub-Assemblies

3.2.1 Piston/Diaphragm Sub-Assembly

1. Remove the diaphragm ➃ from the piston by unscrewing the sleeve ➂ from the piston
using a spanner wrench. Inspect the orifices and clean if necessary. Be careful not to
enlarge the orifices, because performance may suffer. Inspect the diaphragm ➃ for
holes, tears, or accumulated contamination. Discard it if damaged.

2. Inspect the dry bushings ➁ pressed into the sleeve ➂. These bushings are normally
good for several hundred thousand cycles, but they can be replaced when they have
worn out. A worn bushing can be identified by excessive exposure of the sintered
bronze matrix, which is not normally visible. A modest amount of lead /PTFE flakes in
and around the bushing and pin is normal and does not constitute abnormal wear of the
bushing. If there is any doubt about the condition of the bushings, they should be
replaced. Remove by inserting a number 10 machine screw and pulling. There are two
¼ in. long bushings used in tandem. After removal of the old bushings inspect the bore
in the sleeve ➂ for debris and burrs. Clean as necessary. Press two new bushings into
the bore, one at a time, flush to the top of the sleeve.

3. To reassemble, place the diaphragm ➃ on the piston with the inner bead down and the
outer bead up (Figure 6 on page 23). A small amount of vacuum compatible grease
should be smeared on the sleeve side of the diaphragm/sleeve contact area to prevent
puckering of the diaphragm during tightening of the sleeve. Also, if the piston and
sleeve have been degreased prior to assembly, a small amount of vacuum compatible
lubrication should be applied to the male threads of the sleeve to prevent seizing of the
sleeve to the piston. DuPont Krytox® GPL 206 is acceptable. Tighten the sleeve hand
tight. Do not overtighten, this is not a vacuum grade seal.

24

Vacuum Pump Isolation (VPI) Valve

3.2.2 Nose Piece O-ring Replacement

The nose piece O-ring ➄ should be removed only if a new replacement is available.

To remove the old O-ring:

1. Insert a sharp pointed tool, such as a machinist’s scribe obliquely into the ring. The

sharp point must not pass through the seal or the surface of the groove will be damaged.
Lift the seal out with the scribe. Use care not to scratch any of the sealing surfaces.

2. Prepare the new seal by smearing a very light but continuous coat of a vacuum

compatible grease on the O-ring. DuPont Krytox® GPL206, a high quality fluorinated
grease offering low vapor pressure, excellent temperature stability and is chemically
inert is recommended — do not skip this step. Tests have indicated that a dry nose piece
O-ring used in a valve that has been closed for more than two hours is subject to a
breakaway friction exceeding the modest return spring force.

NOTE

To replace the seal:

❑

Position the piston ➀ so that the groove faces upward. Be sure that the bottom of the
groove and surfaces of the new O-ring are free of scratches. If necessary, a suitable
solvent may be used to clean the groove. Particulate contamination may be blown
off with Dust-Off® or dry nitrogen. Place the prepared O-ring from step 2 above on
top of the groove. Place two thumbs on the O-ring at points 180 degrees apart, and
push the O-ring into the groove. Avoid twisting the O-ring as it is pushed in. Then
push in the opposite intermediate points, and so on, until the ring is uniformly in
place.

The return spring has intentionally been designed to be soft so
as to minimize the opening remote pressure burst, thereby
necessitating a boundary layer lubrication at the nose piece
O-ring to control the breakaway friction between the valve seat
and the O-ring.

25

3.3 Reassembly

( )

Vacuum Pump Isolation (VPI) Valve

Figure 7 Assembly View and Replacement Parts

Refer to Figure 7 for these instructions.

1. Slide the piston/diaphragm subassembly onto the guide pin. With the piston facing up so
it does not slide off of the guide pin, place the body down over the piston, flat surface to
the diaphragm. Now invert the body with the bonnet held close and align the bolt holes.
Insert six 10-32 x 7/8 in. socket head cap screws and tighten to 27 in-lb torque.

2. Before returning the valve to service, it should be leak tested.

NOTE

Power will need to be supplied to the solenoid in order to
check the integrity of the body seals as well as the solenoid
itself.

26

Vacuum Pump Isolation (VPI) Valve

3.4 Troubleshooting

This section is a guide for solving problems that may occur with the VPI valve. Listed below
are symptoms with possible causes and suggestions for help.

3.4.1 VPI Valve Cannot Be Pumped Down to High Vacuum

1. Valve leaks from external atmosphere into vacuum system. First check that the solenoid

has proper electrical power applied to the coil. If the solenoid appears to be functional,
then carefully leak test with a quality leak detector. With careless leak detection, a leak
a large distance away can be picked up and the leaking component not found. Some
possible sources of leaks are:

a. Nonsealing flanges between valve and system may be due to damaged flanges,

damaged O-ring, dirt, loose clamps, or incorrect assembly. Locate the problem and
assemble correctly.

b. If a leak signal is obtained at the solenoid/bonnet connection, disassemble, clean,

and reassemble.

c. A leak signal at the solenoid intake indicates a defective solenoid valve.

Disassembly of the solenoid valve is not recommended. Install a new solenoid valve
(see Table 4 on page 31 for part numbers).

2. VPI Valve is dirty and contaminated with a material that is outgassing or blocking the

orifices. Correct by thoroughly cleaning the valve.

CAUTION

If the solenoid valve is replaced by a unit not supplied by
Agilent, it is the responsibility of the user to ensure that it is
sufficiently leak tight to meet the specifications.

3.4.2 VPI Valve Leaks in Closed Position

1. Check for proper installation. The valve has been designed to vent the roughing pump

upon closure. If the valve has inadvertently been installed backwards it would isolate
the pump and vent the system. Reinstall the valve correctly with the flow arrow on the
body label pointing toward the mechanical vacuum pump.

2. The nose piece O-ring ➄ leaks. Confirm leak using a leak detector. Replace O-ring as

described previously.

27

Vacuum Pump Isolation (VPI) Valve

3.4.3 VPI Valve Closes Too Slowly

1. Inlet filter to solenoid valve is clogged. Clean or replace filter.

2. Solenoid valve is defective. Replace with a new solenoid valve.

3. There is excess friction between bushing ➁ and guide pin. Clean and repair the
bushing and guide pin as described in Section 3.2.1 “Piston/Diaphragm Sub-Assembly”
on page 24.

4. The spring is restricted by contamination. Disassemble, clean, or replace.

3.4.4 VPI Valve Opens Too Slowly or Not Completely

1. The orifices are partially blocked. Clean and reassemble.

2. There is excess friction between bushing ➁ and guide pin. Clean and repair the bushing
and guide pin as described in Section 3.2.1 “Piston/Diaphragm Sub-Assembly”.

3. The diaphragm ➃ or spring is contaminated. Disassemble, clean or replace, and
reassemble.

3.4.5 VPI Valve Fails to Open

1. The solenoid valve has a leak or will not close properly preventing the evacuation of the
chamber over the piston. Check to make sure that electrical power has been restored to
the solenoid valve. If the solenoid valve is energized, leak check. If a leak is found in the
solenoid, replace the solenoid.

2. Foreline between the mechanical pump and VPI valve has a major leak preventing the
evacuation of the chamber over the piston. Isolate and correct the leak.

3. Excess friction between bushing ➁ and guide pin. Clean and repair bushing as
described in Section 3.2.1 “Piston/Diaphragm Sub-Assembly” on page 24.

4. The nose piece O-ring ➄ is stuck to valve seat due to excess heat, contamination or the
improper installation of a dry (ungreased) O-ring. Follow the instructions in
Section 3.2.2 “Nose Piece O-ring Replacement”.

5. The diaphragm ➃ or spring is contaminated. Disassemble, clean or replace, and
reassemble.

3.4.6 Closing Causes Large Burst of Air into System

1. Diaphragm ➃ is damaged. Replace with a new diaphragm, see Section 3.2.1 “Piston/
Diaphragm Sub-Assembly”.

2. Diaphragm ➃ has become detached from piston ➀ and sleeve. Inspect and reassemble
as described in Section 3.2.1 “Piston/Diaphragm Sub-Assembly” on page 24.

28

3.4.7 Solenoid Valve is Hot

1. This is a continuous duty valve equipped with Viton seals capable of sustained high

temperature operation. A 85° C temperature rise is normal for this valve.

2. Coil and operating voltage/frequency not matched. Change the solenoid coil to one

with a voltage/frequency compatible with the pump. See Table 3 on page 18.

3. The ambient temperature is too high. The ambient temperature near the solenoid is

limited to less than 50° C due to the temperature rise inherent in the solenoid valve.
Higher temperature rated coils are available on a special request basis if the ambient
cannot be controlled to the 50° C temperature limit. Replace the solenoid valve with a
new one (see Table 3 on page 18) if the unit is too hot and verify that the ambient air
temperature is within limits.

Vacuum Pump Isolation (VPI) Valve

NOTE

CAUTION

It is permissible to remotely place the solenoid valve up to
twelve inches away from the VPI valve using standard ¼ in.
tubing, but this could adversely affect the closing time.

If the solenoid valve is replaced by a unit not supplied by
Agilent, it is the responsibility of the user to ensure that it is
sufficiently leak tight to meet the specifications.

29

Vacuum Pump Isolation (VPI) Valve

3.5 Factory Repair

The VPI valve was designed for user repair, but occasionally it is necessary to return a valve
to the factory. Before shipping, observe the following steps:

1. Call Agilent to obtain a Returned Material Authorization (RMA) number. You will be
asked to fax a completed copy of the Health and Safety Certification form, located in the
back of this document, before an RMA number is issued. This form is used to certify that
the product to be returned does not present any health or environmental risks or
dangers; please read carefully.

NOTE

Figure 8 Contact Agilent Customer Service to obtain a Return Materials Authorization (RMA)
number and a Health and Safety Data Sheet. Return of any part must be accompanied by both

of these completed forms or the shipment will not be accepted.

2. Use the RMA number on all packing slips, boxes, and be prepared to answer the
following questions:

a. What is the problem?

b. What are the symptoms and how are they observed?

c. What is the application?

d. Is it an emergency repair?

e. Is it a warranty repair? When was the valve shipped to you?

f. Who in your organization can answer technical questions about the use of the

valve?

3. Prepare the valve for shipment by capping the ports to prevent entry of foreign material
and to protect the seal surfaces. Place the valve in a sealed plastic bag, and pack it
securely in a sturdy shipping container. Insert a packing slip or letter referencing the
RMA number.

4. If inspection shows the problem to be a warranty matter, the valve will be repaired and
returned free of charge. If it is not covered by warranty, you will be charged for repairs.

30

Vacuum Pump Isolation (VPI) Valve

3.6 Replacement Parts

Table 4 Replacement Parts/Kits

Description Part Number

VPI Rebuild Kit, NW25 VPI25PSTNKIT VPI25RBLDKIT
Includes: Piston Assembly, NW25

❑ Piston
❑ Bearing (2)
❑ Sleeve
❑ Diaphragm

Spring ✓
Krytox Grease ✓

O-ring Kit (also available separately) ✓
VPI Rebuild Kit, NW40 VPI40PSTNKIT VPI40RBLDKIT
Includes: Piston Assembly, NW40

Piston ✓ ✓

❑ Bearing (2)

❑ Sleeve

❑ Diaphragm

Spring ✓

✓ ✓
✓ ✓
✓ ✓
✓ ✓

✓ ✓
✓ ✓
✓ ✓

Krytox Grease ✓

O-ring Kit (also available separately) ✓
O-ring Kit, NW25 and NW40 VPISEALSKIT
Includes: Viton O-ring, 2-142

Viton O-ring, 2-137

Viton O-ring, 2-151
Solenoid Valves
Includes: 90-132 VAC, 50/60 Hz VPISOL1205060

120-146 VAC, 50/60 Hz VPISOL1335060

180-264 VAC, 50/60 Hz VPISOL2205060

239-293 VAC, 50/60 Hz VPISOL2665060

31

Vacuum Pump Isolation (VPI) Valve

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Vacuum Pump Isolation (VPI) Valve

Pg 1/3

NORTH AMERICA:

Fax: [phone]
Toll Free: 800 882 7426, Option 3

[e-mail]

PACIFIC RIM:

please visit our website for individual
office information

http://www.DJLOHQW.com

EUROPE:

Fax: [phone]
Fax Free: 00 800 345 345 00
Toll Free: 00 800 234 234 00

[e-mail]

Vacuum Products Division
Instructions for returning products

Dear Customer:

Please follow these instructions whenever one of our products needs to be returned.

1) Complete the attached Request for Return form and send it to Agilent Technologies (see below), taking particular care to identify
all products that have pumped or been exposed to any toxic or hazardous materials.

2) After evaluating the information, Agilent Technologies will provide you with a Return Authorization (RA) number via email or fax,
as requested.
N

ote: Depending on the type of return, a Purchase Order may be required at the time the Request for Return is submitted. We

will quote any necessary services (evaluation, repair, special cleaning, eg).

3

) Important steps for the shipment of returning product:

xRemove all accessories from the core product (e.g. inlet screens, vent valves).

xPrior to shipment, drain any oils or other liquids, purge or flush all gasses, and wipe off any excess residue.

xIf ordering an Advance Exchange product, please use the packaging from the Advance Exchange to return the defective

product.

xSeal the product in a plastic bag, and package product carefully to avoid damage in transit. You are responsible for loss or

damage in transit.

xAgilent Technologies is not responsible for returning customer provided packaging or containers.

xC

learly label package with RA number. Using the shipping label provided will ensure the proper address and RA number
are on the package. Packages shipped to Agilent without a RA clearly written on the outside cannot be accepted and will
be returned.

4) Return only products for which the RA was issued.

5) P

roduct being returned under a RA must be received within 15 business days.

6) Ship to the location specified on the printable label, which will be sent, along with the RA number, as soon as we have received
a

ll of the required information. Customer is responsible for freight charges on returning product.

7) Return shipments must comply with all applicable S

hipping Regulations (IATA, DOT, etc.) and carrier requirements.

RETURN THE COMPLETED REQUEST FOR RETURN FORM TO YOUR NEAREST LOCATION:

st for Return Health and

Reque

Safety Certification

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Vacuum Pump Isolation (VPI) Valve

Pg 2/3

Vacuum Products Division

Request for Return Form

(Health and Safety Certification)

Please read important policy information on Page 3 that applies to all returns.

1) CUSTOMER INFORMATION

Company Name:

Contact Name:

Tel:

Email:

Fax:

Customer Ship To:

Customer Bill To:

Europe only: VAT reg. Number:

USA/Canada only: Taxable Non-taxable

2) PRODUCT IDENTIFICATION

Product Description

Agilent P/N

Agilent S/N

Original Purchasing Reference

3) TYPE OF RETURN (Choose one from each row and supply Purchase Order if requesting a billable service)

3A.

Non-Billable Billable New PO # (hard copy must be submitted with this form):

3B.

Exchange Repair Upgrade Consignment/Demo Calibration Evaluation Return for Credit

4) HEALTH and SAFETY CERTIFICATION

AGILENT TECHNOLOGIES CANNOT ACCEPT ANY PRODUCTS CONTAMINATED WITH BIOLOGICAL OR EXPLOSIVE HAZARDS,
RADIOACTIVE MATERIAL, OR MERCURY AT ITS FACILITY.
Call Agilent Technologies to discuss alternatives if this requirement presents a problem.

The equipment listed above (check one):

HAS NOT pumped or been exposed to any toxic or hazardous materials. OR
HAS pumped or been exposed to the following toxic or hazardous materials. If this box is checked, the following

information must also be filled out. Check boxes for all materials to which product(s) pumped or was exposed:

Toxic Corrosive Reactive Flammable Explosive Biological Radioactive

List all toxic/hazardous materials. Include product name, chemical name, and chemical symbol or formula:
________________________________________________________________________________________________________

NOTE: If a product is received at Agilent which is contaminated with a toxic or hazardous material that was not disclosed, the customer will be held responsible for all

costs incurred to ensure the safe handling of the product, and is liable for any harm or injury to Agilent employees as well as to any third party occurring as a result of
exposure to toxic or hazardous materials present in the product.

Print Name: Authorized Signature: ………………………. Date:

5) FAILURE INFORMATION:

Failure Mode (REQUIRED FIELD. See next page for suggestions of failure terms):

Detailed Description of Malfunction: (Please provide the error message)

Application (system and model):

I understand and agree to the terms of Section 6, Page 3/3.
Print Name: Authorized Signature: ………………………. Date:

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Vacuum Pump Isolation (VPI) Valve

Pg 3/3

Vacuum Products Division

Request for Return Form

(Health and Safety Certification)

Please use these Failure Mode to describe the concern about the product on Page 2.

TURBO PUMPS and TURBO CONTROLLERS

APPARENT DEFECT/MALFUNCTION

POSITION

PARAMETERS

- Does not start

- Noise

- Vertical

Power: Rotational Speed:

- Does not spin freely

- Vibrations

-Horizontal

Current:

Inlet Pressure:

- Does not reach full speed

-Leak

-Upside-down

Temp 1: Foreline Pressure:

- Mechanical Contact

-Overtemperature

-Other:

Temp 2:

Purge flow:

- Cooling defective

-Clogging

………………….

OPERATING TIME:

ION PUMPS/CONTROLLERS VALVES/COMPONENTS

- Bad feedthrough - Poor vacuum - Main seal leak - Bellows leak

- Vacuum leak - High voltage problem - Solenoid failure - Damaged flange

- Error code on display - Other - Damaged sealing area -Other

LEAK DETECTORS INSTRUMENTS

- Cannot calibrate -No zero/high backround - Gauge tube not working - Display problem

- Vacuum system unstable

- Cannot reach test mode

- Communication failure

- Degas not working

- Failed to start - Other - Error code on display - Other

SCROLL AND ROTARY VANE PUMPS DIFFUSION PUMPS

- Pump doesn’t start - Noisy pump (describe) - Heater failure - Electrical problem

- Doesn’t reach vacuum - Over temperature - Doesn’t reach vacuum - Cooling coil damage

- Pump seized - Other - Vacuum leak - Other

Section 6) ADDITIONAL TERMS

Please read the terms and conditions below as they apply to all returns and are in addition to the Agilent

Technologies Vacuum Product Division – Products and Services Terms of Sale.

xCustomer is responsible for the freight charges for the returning product. Return shipments must comply with all

applicable Shipping Regulations (IATA, DOT, etc.) and carrier requirements.

xCustomers receiving an Advance Exchange product agree to return the defective, rebuildable part to Agilent Technologies

within 15 business days. Failure to do so, or returning a non-rebuildable part (crashed), will result in an invoice for the
non-returned/non-rebuildable part.

xReturns for credit toward the purchase of new or refurbished Products are subject to prior Agilent approval and may incur

a restocking fee. Please reference the original purchase order number.

xUnits returned for evaluation will be evaluated, and a quote for repair will be issued. If you choose to have the unit

repaired, the cost of the evaluation will be deducted from the final repair pricing. A Purchase Order for the final repair price
should be issued within 3 weeks of quotation date. Units without a Purchase Order for repair will be returned to the
customer, and the evaluation fee will be invoiced.

xA Special Cleaning fee will apply to all exposed products per Section 4 of this document.

xIf requesting a calibration service, units must be functionally capable of being calibrated.

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Vacuum Pump Isolation (VPI) Valve

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Published in USA, December, 2012

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