MKS HPS 145 Maintance Manual
Vacuum Sentry
TM
Safety Valve
HPS
TM
Products Series 145
Vacuum Sentry
TM
Safety Valve
Operation and Maintenance Manual
651 Lowell Street
Methuen, MA 01844
Main Telephone: (800) 227-8766 p/n 100010033
www.mksinst.com
Rev. A2
Vacuum Sentry
TM
Safety Valve
Part # 145 - _ _ _ _ _ - _ _ _ _ _ _ - _ _
Serial # _ _ _ _ _ _
Please fill these numbers and have
them readily available when calling for
service or additional information.
(The part number can be found on your
packing slip, and both the part number
and serial number are located on the
bottom side of the housing.)
For more information or literature, contact:
MKS Instruments, Inc.
Phone: 800-227-8766
www.mksinst.com
2015 MKS Instruments, Inc., HPS
IgniTorr, LoPro, HPS
trademarks of HPS
Instruments, Inc. Elgiloy is a registered trademark of Elgiloy Co. OFHCis a registered trademark of Amax, Inc. VCR is a
registered trademark of Cajon Company. Freon, Teflon and Krytox are registered trademarks of E.I. DuPont de nemours & Co.,
Inc. Dust-off is a trademark of Falcon Safety Products, Inc., Mountainside, NJ.
TM
Products Inc. All rights reserved
TM
and Cv are trademarks and MODUCELL, VACUUM SENTRY
TM
, a division of MKS Instruments, Inc. SensaVac and Baratron are registered trademarks of MKS
TM
and AUTO-SOFT are registered
Vacuum Sentry
TM
Safety Valve
Table of contents
Table of contents ....................................................................... 3
Package Contents ..................................................................... 1
Symbols Used in this Manual .................................................... 1
General Description of Vacuum Sentry
Operating Principles Vacuum Sentry
Vacuum Sentry
Normal Operation - Open position. ............................................................................... 4
Power Interruption ......................................................................................................... 4
Valve closed - Mechanical pump vented ...................................................................... 5
Power restored .............................................................................................................. 5
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Operation Sequence .................................................. 4
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.............................................................
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...................................................................
2
3
Specifications ............................................................................ 6
Installation ................................................................................. 7
Electrical ................................................................................................. 7
Mechanical ............................................................................................. 7
Service ...................................................................................... 8
Disassembly ........................................................................................... 8
Repair of Subassemblies ........................................................................ 9
Piston / Diaphragm Subassembly ................................................................................ 9
Nose Piece O-ring Replacement .................................................................................. 9
Bonnet Subassembly .................................................................................................. 10
Reassembly ................................................................................................................ 10
Troubleshooting ....................................................................... 12
Valve Cannot Be Pumped Down to High Vacuum ................................ 12
Valve Leaks in Closed Position ............................................................. 13
Valve Closes Too Slowly ....................................................................... 13
Valve Opens Too Slowly or Not Completely ......................................... 13
Valve Fails to Open ............................................................................... 13
Closing Causes Large Burst of Air into System ................................... 14
Solenoid Valve is Hot ............................................................................ 14
Factory Repair ...................................................................................... 15
Accessories / Part Replacement ............................................. 16
Product Warranty ..................................................................... 17
Notes ....................................................................................... 1
Package Contents
Vacuum Sentry
TM
safety Valve
1
Before unpacking your Series 145 Vacuum Sentry
TM
, check all surfaces of
the packing material for shipping damage.
Please be sure that your Series 145 Vacuum Sentry
TM
package contains
these items:
1 Series 145 Vacuum Sentry
1 Series 145 Vacuum Sentry
TM
TM
Manual
Inspect the Series 145 for visible evidence of damage. If it has been damaged
in shipping, notify the carrier immediately. Keep all shipping materials and
TM
packaging for claim verification. Do not return the product to HPS
Symbols Used in this Manual
The first two symbols below, that may be located on your Series 145
Vacuum Sentry
throughout this manual to fur ther define the safety concerns associated
with the product.
The last two symbols identify other information in this manual that is
essential or useful in achieving optimal performance from the Series 145
Vacuum Sentry
CAUTION: Risk of electrical shock.
CAUTION: Refer to manual. Failure to read message could result
in personal injury or serious damage to the equipment or both.
Failure to read message could result in damage to the equipment.
Calls attention to important procedures, practices, or conditions.
TM
, identify critical safety concerns. They are used
TM
.
2 Vacuum Sentry
TM
safety Valve
General Description of
TM
Vacuum Sentry
TM
HPS
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. Vacuum
Sentry
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.
Fast acting Vacuum Sentry
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
minimized by the unique patented buffer volume design. Vacuum
Sentry
standard ISO-KF dimensions are used for the NW 40 KF and NW 50 KF
sizes, 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, Vacuum Sentry
pump’s integral valve will not vent it and is undependable.
Products Series 145 Vacuum Sentry
TM
is offered with the ISO-KF flange sizes and solenoid voltages /
TM
is light weight, constructed of vacuum
TM
consumes little power. Installation is simplified, because the
TM
is a safety valve, which
TM
should be used, because the
Vacuum Sentry
TM
safety Valve
3
TM
Operating Principles
Vacuum Sentry
Vacuum SentryTM’s solenoid valve is connected in parallel with the
mechanical pump’s electrical supply either at its source or at the pump’s
switch. See figure 1. When the electrical power is on, the solenoid valve is
closed, allowing the pump to keep Vacuum Sentry
system evacuated. Interruption of electrical power to the mechanical pump
causes the solenoid valve to open admitting air into Vacuum Sentry
causing it to close very quickly. This isolates the vacuum system from the
mechanical pump, while the pressure deferential 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
echanical pump is restarted, it evacuates the area above the piston
the m
until the pressure is lowered to approximately that of the vacuum system.
Vacuum Sentry
be pumped at the full speed of the mechanical pump.
TM
automatically opens again allowing the vacuum system to
TM
’s body and the vacuum
TM
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