Agilent Technologies VPI Series User manual

INSTRUCTION MANUAL
Vacuum Products Division
Vacuum Pump
Isolation (VPI) Valve
Manual No. 699912117
Revision F
December 2012

Vacuum Pump Isolation (VPI) Valve
Copyright 2012
Agilent, Inc.
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.

Vacuum Pump Isolation (VPI) Valve
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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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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

Vacuum Pump Isolation (VPI) Valve
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Vacuum Pump Isolation (VPI) Valve
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Tables
1 Technical Specifications ..................................................................................................... 16
2 Operating Voltages............................................................................................................. 17
3 VPI Valve Installation Data ................................................................................................. 18
4 Replacement Parts/Kits ...................................................................................................... 31

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9
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 war-
ranty, 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 adjust-
ment, 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, notwith-
standing 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

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Hazard and Safety Information
This manual uses the following standard safety protocols:
WARNING 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.
CAUTION The caution messages are displayed before procedures, which
if not followed, could cause damage to the equipment.
NOTE The notes contain important information.
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.
Vacuum Equipment and Cleanliness
Cleanliness is vital when servicing any vacuum equipment.
CAUTION 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.
NOTE 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).

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O-ring Care
When removing, checking or replacing O-rings, keep in mind the following:
NOTE Agilent recommends replacing all O-rings during routine
maintenance or during any maintenance procedure requiring
that O-rings be removed.
CAUTION 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.
Contacting Agilent
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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13
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.

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1.3 Operation Sequence
Figure 1 Operating Sequence

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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.

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1.4 Technical Specifications
Table 1 Technical Specifications
Nominal body ID 2 in. (50 mm)
Leak rate
❑Body <1 x 10-9 atm cc/sec He
❑Seal <1 x 10-9 atm cc/sec He
Closing time 30 milliseconds
Closing burst 1 x 10
-2
Torr-liter
Power 7.0 Watts for AC applications
5.8 Watts for TriScroll inverter pump
applications
Materials
❑Body and flanges Extruded aluminum (6061 -T6)
❑Piston Machined aluminum (2024)
❑Seals (O-ring and diaphragm) Viton
❑Guide pin 304 stainless steel
Temperature range (valve) 0°to 100°C
Temperature range (solenoid) 0°to 50°C
Venting time
❑NW40 10 s/
ι of vented volume
❑NW25 50 s/
ι of vented volume

17
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
NW40
VPI Valve
Part Number
Solenoid Operating
Voltage Range Maximum Operating Current
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

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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.
NOTE To prevent damage to the VPI Valve it must be installed only as
specified below.
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.
Table 3 VPI Valve Installation Data
TriScroll
Vacuum Pump
Operating Voltage
NW25
VPI Valve
Part Number
NW40
VPI Valve
Part Number
Solenoid
Operating
Voltage Range
Wiring Diagram
Location
100-120 VAC
50/60 Hz
1 Phase
VPI251205060 VPI401205060 90-132 VAC
50/60 Hz Figure 2 on page 19 Low Voltage
200-230 VAC
50/60 Hz
1 Phase
VPI251205060 VPI401205060 90-132 VAC
50/60 Hz * Figure 2 on page 19 High Voltage
200 VAC
50/60 Hz
3 Phase
VPI251205060 VPI401205060 90-132 VAC
50/60 Hz * Figure 3 on page 19 Low Voltage
230 VAC
50/60 Hz
3 Phase
VPI251335060 VPI401335060 120-146 VAC
50/60 Hz * Figure 3 on page 19 Low Voltage
380 VAC
50/60 Hz
3 Phase
VPI252205060 VPI402205060 180-264 VAC
50/60 Hz * Figure 3 on page 19 High Voltage

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Figure 2 Single Phase Motor Electrical Connections
Figure 3 Three Phase Motor Electrical Connections
415 VAC
50/60 Hz
3 Phase
VPI252205060 VPI402205060 180-264 VAC
50/60 Hz * Figure 3 on page 19 High Voltage
460V 50/60 Hz
3 Phase VPI252665060 VPI402665060 239-293 VAC 50/60 Hz * Figure 3 on page 19 High Voltage
*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.
Table 3 VPI Valve Installation Data (Continued)
TriScroll
Vacuum Pump
Operating Voltage
NW25
VPI Valve
Part Number
NW40
VPI Valve
Part Number
Solenoid
Operating
Voltage Range
Wiring Diagram
Location
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

Vacuum Pump Isolation (VPI) Valve
20
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.
P1
Communication
Cable
VPI Valve
Mains Power Input
Splitter Cord
24 VDC
Power Supply