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America
Varian Vacuum Technologies
121 Hartwell Avenue
Lexington, MA 02421,
USA
Tel: (781) 861 7200
Fax: (781) 860 5437
Toll Free: 1 (800) 882 7426
Argentina
Varian Argentina Ltd.
Sucursal Argentina
Av. Ricardo Balbin 2316
1428 Buenos Aires
Argentina
Tel: (54) 1 783 5306
Fax: (54) 1 786 5172
Australia
Varian Australia Pty., Ltd.
6/81 Frenchs Forest Road
Frenchs Forest, NSW 2086
Australia
Tel: (61) 2 9975 8805
Fax: (61) 2 9452 2600
Brazil
Varian Industria e Comercio Ltda.
Avenida Dr. Cardoso de Mello 1644
Vila Olimpia
Sao Paulo 04548 005
Brazil
Tel: (55) 11 820 0444
Fax: (55) 11 820 9350
Canada
Varian Canada
6705 Millcreek Drive, Unit 5
Mississauga, Ontario L5N 5R9
Canada
Tel: (905) 819 8188
Fax: (905) 819 8348
China
Varian China Ltd.
Room 1201, Jinyu Mansion
No. 129A Xuanwumen Xidajie
Xicheng District
Beijing 100031
P.R. China
Tel: (86) 10 6641 1530
Fax: (86) 10 6641 1534
Varian Shanghai
Service Station
716 Yishan Road Shanghai
P.R. China 200233
Tel: (86) 21 6483 5576
Fax: (86) 21 6485 9031
England
Varian Ltd.
28 Manor Road
Walton-On-Thames
Surrey KT 12 2QF
England
Tel: (44) 1932 89 8000
Fax: (44) 1932 22 8769
France
Varian s.a.
7 avenue des Tropiques
Z.A. de Courtaboeuf – B.P. 12
Les Ulis cedex (Orsay) 91941
France
Tel: (33) 1 69 86 38 38
Fax: (33) 1 69 28 23 08
Germany
Varian GmbH
Alsfelder Strasse 6
Postfach 11 14 35
64229 Darmstadt
Germany
Tel: (49) 6151 703 353
Fax: (49) 6151 703 302
Hong Kong
Varian Technologies Asia, Ltd.
Rm 2611 Concordia Plaza
New Mandarin Plaza
1 Science Museum Rd.,
Tsimshatsui East, Kowloon
Hong Kong
Tel: (852) 26206173
Fax: (852) 26206338
India
Varian India PVT LTD
1010 Compotent House
7, Nangal Raya Business Centre
New Delhi 110 046
India
Tel: (91) 11 5548444
Fax: (91) 11 5548445
Italy
Varian Vacuum Technologies
via Flli Varian 54
10040 Leini, (Torino)
Italy
Tel: (39) 011 997 9111
Fax: (39) 011 997 9350
Japan
Varian Vacuum Technologies
Sumitomo Shibaura
Building, 8th Floor
4-16-36 Shibaura
Minato-ku, Tokyo 108
Japan
Tel: (81) 3 5232 1253
Fax: (81) 3 5232 1263
Korea
Varian Technologies Korea, Ltd
Shinsa 2nd Bldg. 2F
966-5 Daechi Dong
Kangnam Gu, Seoul
Korea 135-280
Tel: (82) 2 3452 2452
Fax: (82) 2 3452 2451
Netherlands
Varian Vacuum Technologies
Rijksstraatweg 269 H,
3956 CP Leersum
The Netherlands
Tel: (31) 343 469910
Fax: (31) 343 469961
Mexico
Varian S.A.
Concepcion Beistegui No 109
Col Del Valle
C.P. 03100
Mexico, D.F.
Tel: (52) 5 523 9465
Fax: (52) 5 523 9472
Singapore
Varian Asia, Ltd.
1123 Serangoon Road
#03-02
Singapore 328207
Tel: (65) 296 9688
Fax: (65) 296 9733
Spain
Varian Iberica
Avda Pedro Diez 25
28019 Madrid
Spain
Tel: (34) 91 4727612
Fax: (34) 91 4725001
Russia
Varian Moscow
19A Khlebny per
121019 Moscow
Russia
Tel: (70) 95 9374280
Fax: (70) 95 9374281
Taiwan
Varian Technologies Asia Ltd.,
Taiwan Branch
18F-13 No.79, Hsin Tai Wu Road
Sec. 1, Hsi Chih
Taipei Hsien
Taiwan
Tel: (886) 2 2698 9555
Fax: (886) 2 2698 9678
Internet Users:
Visit us on the web at:
www.eVarian.com
Representatives in most countries
Sales and Service Offices
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 war-
ranty claims is limited, at the option of Seller, to repair, replacement, or refund of an equitable portion
of the purchase price of the Product. Items expendable in normal use are not covered by this war-
ranty. 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, mis-
use, or neglect of the equipment. In-warranty repaired or replacement 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 cur-
rent 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 repre-
sentative. 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 rea-
son, 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 examina-
tion may be made on Products so returned.
3/5/97
i
OPERATION AND MAINTENANCE OF THIS EQUIPMENT INVOLVES SERIOUS RISK. IT IS THE
RESPONSIBILITY OF THE USER TO MAINTAIN SAFE OPERATING CONDITIONS AT ALL TIMES.
VARIAN ASSUMES NO LIABILITY FOR PERSONAL INJURY OR DAMAGE RESULTING FROM
OPERATION OR SERVICE OF THE EQUIPMENT.
Carelessly or improperly operated equipment can cause serious injury or death and/or damage to the
equipment. The emergency and safety procedures in this manual are provided to help users and
qualified persons to operate and service the unit safely. Recommendations are believed to reflect
accepted industry practices in effect on the date of publication of this manual. Special applications
must be reviewed and approved by an industrial hygienist or chemical safety engineer.
Varian has no control over the use of this equipment and is not responsible for personal injury or
damage resulting from its use. The safe use and disposal of hazardous or potentially hazardous
materials of any kind is the sole responsibility of the user. Observe all WARNINGS and CAUTIONS to
minimize the serious hazards involved.
It is the sole responsibility of users of Varian equipment to comply with all local, state, and federal safety
requirements (laws and regulations) applicable to their system. Employ the services of an industrial
hygienist and/or a qualified chemical safety engineer in order to ensure safe installation and use.
This instruction manual contains information which will assist qualified operators in the operation, and
qualified service engineers to carry out field-servicing the Varian equipment.
ii
SAFE INCORPORATION OF VARIAN DIFFUSION PUMPS INTO VACUUM SYSTEMS IS THE
RESPONSIBILITY OF THE SYSTEMS DESIGNER. TAKE APPROPRIATE ACTION THROUGH
REDUNDANCY, AND/OR OTHER SAFEGUARDS TO PROTECT PERSONNEL AND PROPERTY
FROM THE HAZARDS DESCRIBED BELOW AND IN THE INSTALLATION, OPERATION, AND
MAINTENANCE INSTRUCTION MANUAL. SAFE OPERATION IS THE RESPONSIBILITY OF THE
USING ORGANIZATION AND ITS PERSONNEL. READ THE INSTRUCTION MANUAL AND
UNDERSTAND HOW TO AVOID HAZARDS PRIOR TO OPERATING THE DIFFUSION PUMP. ALL
PERSONS WHO WORK WITH OR ARE EXPOSED TO DIFFUSION PUMPS OR EQUIPMENT
WHICH UTILIZES SUCH PUMPS OR DIFFUSION PUMP FLUID MUST TAKE PRECAUTIONS TO
PROTECT THEMSELVES AGAINST POSSIBLE SERIOUS BODILY INJURY OR DEATH. DO NOT
BE CARELESS AROUND SUCH PRODUCTS.
THESE SHEETS AND THE INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS
CAN HELP YOU TO OPERATE THIS PUMP SAFELY AND EFFICIENTLY. READ THEM. SPECIAL
OPERATING CONSIDERATIONS AND PRECAUTIONS WILL BE FOUND IN THE OPERATION
INSTRUCTIONS. UNINFORMED OR CARELESS OPERATION OF THIS PUMP CAN RESULT IN
POOR PERFORMANCE, DAMAGE TO THE PUMP OR OTHER PROPERTY, SERIOUS BODILY
INJURY, AND POSSIBLE DEATH.
USERS OF THIS EQUIPMENT SHOULD BE ALERT TO TWO LEVELS OF HAZARDS IDENTIFIED
BY THE FOLLOWING SYMBOLS:
Designers of systems which utilize diffusion pumps must design out hazards wherever possible; pro-
vide guards, safety features, and interlocks for hazards which cannot be designed out; warn with
respect to hazards which cannot be designed out and which remain after utilizing guards, safety fea-
tures, and interlocks; and lastly, provide procedures and instructions on proper use, servicing, etc., so
as to minimize risk.
WARNING
_____________
Warnings are used when failure to observe instructions or precautions
could result in injury or death to humans.
CAUTION
________
Cautions are used when failure to observe instructions could result in
significant damage to equipment and/or facilities.
iii
THE INSTALLATION, OPERATION, AND/OR SERVICING OR DIFFUSION PUMPS INVOLVES ONE
OR MORE OF THE FOLLOWING HAZARDS, ANY ONE OF WHICH, IN THE ABSENCE OF SAFE
OPERATING PRACTICES AND PRECAUTIONS, COULD POTENTIALLY RESULT IN DEATH OR
SERIOUS HARM TO PERSONNEL.
Hazard Suggested Corrective Action
Loss of utility: water and/or electricity Provide sufficient water and backup power to effect a safe
shutdown under worst case conditions.
Overpressure in foreline Provide an interlock to ensure that the power supply to the
pump heater cannot be activated if the foreline pump is not run-
ning AND/OR pressure in foreline is above 0.5 Torr (66.5 Pa).
Overtemperature Fit temperature sensors and pump fluid level sensors with
feedback to an interlock on the heater power supply.
Insufficient water flow through the Use water flow sensor and feedback to interlock on the heater
main cooling coils power supply.
Water trapped between inlet and Provide vent or pressure relief valves for both quick-cool coil
outlet of quick-cool coil, or liquid and liquid nitrogen trap.
nitrogen trapped between inlet and
outlet of liquid nitrogen trap
Loss of ground integrity Incorporate ground fault interrupt circuit into heater
power supply.
Positive pressure in pumping system Integrate pressure relief valve in vacuum system.
High voltage (up to 480 V) Prevent personnel contact with high voltages; design and
attach warnings.
Toxicity/Corrosivity Toxic and/or corrosive gases must be vented to a safe
location, ensuring adequate dilution or scrubbing to safe
levels, taking all action required to meet air quality standards.
Explosion Integrate pressure relief valves in all systems using pumps
10 inches or larger in diameter.
Do not use or recommend the use of hydrocarbon-based
pumping oils.
iv
Hazard Suggested Corrective Action
a. Explosion – Operation of the diffusion pump without prior and continuous evacuation (below 0.5
Torr (66.5 Pa)) or coolant and introducing a strong oxidizer (such as air) or explosive vapors or
powders or materials which may react with pumping fluids into a hot (above 300°F or 150°C) pump
can cause an explosion. Such an explosion can violently expel valves and other hardware, slam
open doors that are not designed for appropriate pressure relief, or burst other components of the
vacuum system. Serious injury or death may result from expelled parts, doors, shrapnel, and/or
shock waves.
b. All diffusion pumps are typically cleaned with acetone and alcohol. When combined with air,
oxygen, and other oxidizers, alcohol and most other solvents are very flammable and explosive.
Never permit any trace of these cleaners to remain in or on the pump. Always remove all traces of
alcohol and acetone and other cleaners with clean, dry, oil-free compressed air.
Three elements are required: fuel, oxidizer, and source of ignition. A combination of temperature and
pressure can be a source of ignition. Most diffusion pump fluids except mercury are fuels. Hydrocarbon
oils are more prone to oxidize and explode than synthetic silicone-based oil. Oxidizers can be air (a
strong oxidizer) from a leak or can be deliberately introduced in a process or can be inadvertently
admitted to the system by operator or process controller error. Oxygen and other strong oxidizers are
even more dangerous. Certain conditions of temperature and pressure can cause a combustible mix-
ture to explode. The larger the diffusion pump, the greater the risk of explosion and the greater the risk
of damage and/or injury. Never operate diffusion pumps larger than 10 inches in diameter with hydro-
carbon oils without a full safety analysis for the complete system and application. Never operate any dif-
fusion pump in the following ways because they increase the probability of an explosion.
Prohibited Action Explosion-Causing Condition
Run pump with no cooling water Overtemperature
Run pump with low level of pump fluid Overtemperature
Run pump without proper backing or Overpressure
holding pump
Run pump when not evacuated below Overpressure
0.5 Torr (66.5 Pa)
Admit air to, or rough through, Overpressure plus strong oxidizer
a pump with hot boiler
Open drain or fill plug while pump is Overpressure plus strong oxidizer
under vacuum, especially when it is hot
v
Prohibited Action Explosion-Causing Condition
Contaminate pump with explosive vapors, Lower explosive threshold of gas mixtures
powders, or reactive materials
Remove, defeat, or override safety counter- Overtemperature, overpressure, more
measures such as pressure and thermal combustible mixtures
switches and valve sequencer interlocks
Machine or weld without removing all oil Source of ignition
or solvent residue in pump
Use unsuitable pumping fluid especially Lower explosive threshold of gas mixture
in large pumps
Systems larger than 10 inches must be designed with pressure relief devices to provide safe pres-
sure relief from internal explosions. Always recognize that safety devices can fail or malfunction. Pro-
vide redundant protection by installing devices having different failure modes, failure mechanisms,
and failure causes. Be certain that exhaust duct materials are capable of withstanding the corrosivity,
temperature, and pressure of exhausted products.
c. Pressure – Pumps and their components are designed for vacuum service; they are not designed
to be pressurized which could cause them to burst possibly expelling shrapnel at lethal velocities.
Serious accidents have been caused by intentional pressurization of vacuum systems and their
components. Never pressurize any part of a vacuum system for test or any other purpose.
Always provide pressure relief when designing diffusion pumps into systems and ensure that pres-
sure relief motion is limited to safe envelopes. Never permit the following:
Prohibited Action Result
Block inlet and vent of liquid nitrogen LN2trap and/or lines burst
trap and lines
Close isolation valves at inlet and discharge Water turns to steam and bursts coils
of main watercooling coils and pump is
reheated
Pressurize pump body Body of pump bursts
Hole through vacuum wall Loss of structural integrity of wall
vi
d. Poisonous and/or Corrosive Compounds – When pumping poisonous, reactive, and/or corrosive
gas, vapors, or chemicals, even proper operation and regeneration will not always ensure that all
hazardous materials have been totally removed. If hazardous gas, vapors, chemicals, or combustible
mixtures are pumped, sufficient quantities may exist during operation or remain after regeneration to
cause severe injury or death. Overheating the pump oil, exposing it to air or reactive materials, or
overpressurizing it above the normal operating range (approximately 1 mTorr (.133 Pa)) will decom-
pose the oil and possibly make it toxic. This is especially true of backstreamed mechanical pump oils
which are more volatile (unstable). Overheating of accidentally introduced or backstreamed mechan-
ical pump oils cannot be protected against by thermal switches which are set for diffusion pump oil.
d. Refer to specific instruction manuals for detailed instructions and precautions. Always vent the
pump and relief valve to a safe location thus ensuring adequate dilution to safe levels, and take all
other action required to meet quality air standards. Always handle pump fluids and hardware with
an awareness of the possible deadly hazards involved and the necessity for great care and atten-
tion to safety precautions.
d. Diffusion pumps are typically cleaned with acetone or alcohol. Acetone, alcohol, and most other
solvents are irritants, narcotics, and depressants, and/or carcinogenic. Their inhalation and inges-
tion may produce serious effects. Even absorption through the skin can result in moderate toxicity.
Always ensure that cleaning operations are performed in large, well-ventilated rooms. Use of self-
contained breathing apparatus may be necessary depending upon the solvent type and vapor
concentration in surrounding air.
e. High Voltage – Diffusion pumps operate at voltages (up to 480 V) high enough to kill through
electrical shock. Design equipment utilizing these pumps to prevent personnel contact with high
voltages. Securely attach prominent hazard warnings. Personnel should always break the primary
circuit to the power supply when direct access to the heater or wiring is required.
f. Hot Surfaces – Boiler temperatures reach 530°F (275°C) which can cause serious burns when
touched. Always ensure that surfaces have cooled near room temperature before touching them.
g. Hot Coolant and/or Steam – The water used to cool the pump can reach scalding temperatures.
Touching or rupture of the cooling surface can cause serious burns. Water left inside quick cool
coils from previous use will turn to steam when the pump is reheated. This steam must be allowed
to escape without contacting personnel. Whenever possible, design the water system with inter-
lock valves so that power cannot be applied to the pump unless water is flowing in the main cool-
ing coils (not quick-cooling coils).
h. Cold Surfaces – Liquid nitrogen traps cooled by liquid nitrogen are commonly used in diffusion
pumps. Metal surfaces at liquid nitrogen temperature can cause severe frostbite if contacted by
unprotected skin. These surfaces remain cold for some time (at least a half hour) after the liquid
nitrogen has evaporated.
vii
i. Cold Coolant – Liquid nitrogen, a cryogenic liquid, is used in traps. If it is splashed on body tissues
or eyes, it can cause severe frostbite or blindness. The extremely low temperature of liquified nitro-
gen can cause skin damage similar to high temperature burns. Contact with the cold gas evolving
from the liquid may produce the same effect. Delicate tissues, such as the eye tissues, are most
easily damaged by exposure to cold gas or liquid. To minimize the risk of hazardous contact of cold
gaseous nitrogen with any part of the body, wear personal safety equipment recommended for use
with cryogenic materials including face shield, full-sleeved lab coat, and clean, dry gloves which fit
loosely so they can be thrown off quickly if frozen by contact with the gas.
j. Asphyxiation – If a large amount of liquid nitrogen is spilled in a small, poorly ventilated room or
equipment, death from suffocation can result. All diffusion pumps are typically cleaned with acetone
or alcohol. Acetone, alcohol, and most other solvents are very volatile (unstable). During cleaning,
the volatility of these cleaners may permit their gases to displace air and its life-supporting oxygen
which could cause death or serious injury by asphyxiation. Always ensure that cleaning operations
are performed in large, well-ventilated areas.
j. While still hot, the diffusion pump may also contain decomposed and/or overheated pump oils
which can also be an asphyxiant.
k. Large, Heavy Weights – Diffusion pumps larger than 10 inches in diameter require power-
assisted equipment and the use of trained moving/installation personnel in order to avoid
dropping, slipping, and/or overturning the pump thus severely injuring personnel. Check weight
of equipment before lifting and do not stand under equipment being moved.
viii
WARNING
_____________
High voltages (up to 480 V) can kill. Always break the primary circuit to
the power supply before starting to work on the heater and/or its wiring.
WARNING
_____________
Certain gases can become corrosive and toxic when trapped in oil.
Always wear protective gloves when handling dirty pump oil, drain it into
a closable container, and do not breathe the fumes of the oil. Always
use fully self-contained breathing apparatus.
WARNING
_____________
Diffusion pumps are typically cleaned with acetone, alcohol, or other
solvents.
When heated, sprayed or exposed to high temperature equipment,
these solvents become flammable and explosive, causing serious injury
or death. Do not use near a high-temperature source. Ventilate work-
ing area with a blower and use in large, well-ventilated room. When
heated or sprayed, solvents also becomes 4 to 5 times heavier than air
and will flow down, settling in tanks, pits, and low areas, thus displacing
air which can kill by asphyxiation. Use in a large, well-ventilated room.
Use of a self-contained breathing apparatus may be necessary.
Acetone, alcohol, and other solvents are irritants, narcotics, depres-
sants, and/or carcinogenics. Their inhalation and/or ingestion may pro-
duce serious effects. Prolonged or continued contact with the skin will
result in absorption through the skin and moderate toxicity. Always
ensure that cleaning operations are carried out in large, well-ventilated
rooms, and wear eyeshields, gloves, and protective clothing.
WARNING
_____________
Varian has no control over the types of gases passing through this
pump. These are entirely under the control of the process user and/or
the hardware systems integrator. Frequently, process gases are toxic,
flammable, corrosive, explosive, or otherwise reactive. Since these
gases can cause serious injury or death, it is very important to plumb
the exhaust of the pump to the facility’s hazardous gas exhaust system
which incorporates appropriate filters, scrubbers, etc., to insure that the
exhaust meets all air and water pollution control regulations.
ix
NOTE
________
Always dispose of used or dirty oil properly and in compliance with all
local, state, and federal environmental laws and regulations.
CAUTION
________
Alcohol, acetone, and other solvents degrade O-ring materials reducing
their ability to hold a vacuum. Do not use acetone or other solvents on
O-rings. If necessary to clean O-rings, wipe with lint-free, clean cloth,
wash in detergent and water, or use a small amount of pump oil.
WARNING
_____________
When lifting some Varian diffusion pumps, use power-assisted equip-
ment and trained moving/installation personnel to avoid dropping, slip-
ping, and/or overturning the pump and severely injuring personnel.
Check weight of equipment before lifting and do not stand under equip-
ment being moved.
WARNING
_____________
Hot oils can cause serious burns. Wear protective gloves and long
sleeved, loose fitting, heat resistant garments when draining pump oil.
WARNING
_____________
If hazardous gas, vapors, chemicals, or combustible mixtures are
pumped, sufficient quantities may exist during operation. This pump may
contain decomposed and/or overheated pump oils or poisonous and/or
overheated pump oils or poisonous and/or corrosive process materials
which are highly toxic and also can be an asphyxiant. Proper operation
will not always ensure that all hazardous materials have been removed.
x
Table of Contents
Section Page
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Section I – Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-2 Operating Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-3 Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1-4 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1-5 Cleaning a New Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1-6 Utility and System Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
1-7 Adding Pump Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Section II – Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-1 Start-up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-2 Shutdown Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Section III – Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3-2 Periodic Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3-3 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3-4 Disassembling and Reassembly the Cold Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3-5 Disassembling and Reassembling the Jet Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3-6 Heater Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3-7 Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Section IV – Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-1 Leakage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-2 Outgassing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-3 Poor Pump or System Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
List of Illustrations
Figure Title Page
1-1 Speed and Throughput Curves – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . 1-2
1-2 Physical Specifications – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1-3 Section Drawing – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1-4 Water Cooling Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
1-5 240/400/440V Wiring Diagram – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . . 1-10
1-6 380/415V Wiring Diagram – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1-7 480V Wiring Diagram – NHS-35 Diffusion Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
1-8 Sight Glass Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
3-1 Heater Element Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3-2 External Fittings – Cold Cap Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
List of Tables
Table Title Page
4-1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
1-1
SECTION I
INSTALLATION
1-1 GENERAL
Upon receipt, inspect the container for evidence of damage in shipment. Do not discard any evidence of
rough handling. Factory packing provides for maximum protection during shipment. However, the pump
should be inspected immediately and any damage should be reported to the carrier without delay.
Before unpacking and installing the pump, the user should thoroughly familiarize himself wiith the
contents of this instruction manual, particularly the physical and operating specifications listed in the
following paragraphs, in order to gain a better understanding of the operating principles, limitations,
correct application of the diffusion pump, the hazards involved, and what to do and what not to do in
order to avoid these hazards.
1-2 OPERATING SPECIFICATIONS
Model Part Number
NHS-35 Diffusion Pump 240 V 480 V 380/415 V 400 V 440 V
with ASA flanges & standard cold cap F1730308 F1730309 F1730326 F1730362 F1730364
with ASA flanges and halo baffle F1730318 F1730319 F1730336 F1730363 F1730365
with ISO flanges & standard cold cap L5924308 L5924309 L5924326 – –
with ISO flanges and halo baffle L5924318 L5924319 L5924336 – –
Optimum Operating Range 6 x 10-4 torr to < 5 x 10-8 torr
(8 x 10-2 Pa to < 7 x 10-6 Pa)
(8 x 10-4 mbar to < 7 x 10-8 mbar)
Maximum Pumping Speed 50,000 liters/sec for air
(See Figure 1-1) 62,500 liters/sec for helium
Maximum Throughput 35 torr-liters/sec at 10-2 torr
4655 Pa - liters/sec @ 1.33 Pa
46.5 mbars - liters/sec @ 0.013 mbar
Maximum Forepressure No Load – 0.55 torr (73.2 Pa) (0.73 mbar)
Full Load – 0.40 torr (53.2 Pa) (0.53 mbar)
Backstreaming Rate at Pump Inlet 0.0005 mg/cm2/min (with cold cap)
Power Required (approximately) 24 KW, 240/380/415/440/480V, 50/60 Hz, 3-phase
Warmup Time 60 hour
Cooldown Time (using quick cool) 180 minutes (60 minutes)
Fluid Charge 3 gallons
Cooling Water Requirements 4 gpm at 60°F to 80°F inlet temperatures
Backing Pump Size Recommended 300 cfm for optimum throughput
Installation
1-2
Figure 1-1. Speed and Throughput Curves – NHS-35 Diffusion Pump
Installation
1-3
1-3 PHYSICAL SPECIFICATIONS (See Figure 1-2)
Flange dimensions (inches):
ASA
Inlet Foreline Inlet Foreline
35"ASA 6"ASA ISO-1000-F ISO-200-K*
OD 41.75 11 44.09 9.45
ID 35 7.72 35.00 7.72
Thickness 1.12 0.75 1.12 0.47
Bolt Circle 38.5 9.5 42.913 –
No. of Holes 28 8 32 –
Size of Holes 0.87 0.81 0.550 –
Orientation Straddle center line
Gasket Groove ID 35.37 8.20 40.75 –
wide 0.56 0.17 0.56 –
deep 0.25 0.09 0.25 –
Height 72.13 inches; allow additional 8 inches (min) for
heater removal
Jet Assembly 5-stage, Self-aligning, fractionating design with four
diffusion stages and one ejector stage
Foreline Baffle Stacked disk and ring
Cold Cap Water-cooled
Water Connections 3⁄8FPT for pump body and quick-cool coils
Thermal Switches Upper set at 200°F (92°C)
Lower set at 600°F (315°C)
Materials
Body Mild steel
Flanges Mild steel
Jet Assembly Stainless Steel
Foreline Baffle Mild Steel
Weight 1220 pounds (pump)
250 pounds (jet assembly)
Shipping Weight 1550 pounds (705 kg)
* Requires NW-200 centering ring (not included with pump)
Installation
1-4
Figure 1-2. Physical Specifications – NHS-35 Diffusion Pump (with ASA Flanges)
(optional)
Installation
1-5
1-4 UNPACKING
Pumps are factory-packaged to permit prolonged storage in suitably protected areas without special
precautions.
a. Remove flange covers, blank plugs, protective plugs from water connections, etc. Be careful
not to scratch or otherwise damage or mar the sealing surface.
b. Carefully remove the outer shipping container and save it for evidence if damaged. Notify
the carrier immediately. Visually inspect the pump for damage that may have occurred
during shipping. Discard any internal packing which may have been used to protect the
internal components.
c. For non-critical work, after making sure that there are no foreign materials inside the pump,
it may be charged with fluid and used without disassembly. Otherwise, it should be disassem-
bled and cleaned. In general, cleaning may be required if the expected vacuum level is to be
below the 10-6 Torr (.000133 Pa) range.
d. Check the internal jet assembly. It should be concentric and firmly seated on the bottom of the
pump. Using a flashlight, check to make sure that the ejector nozzle is opposite the foreline
(the pump outlet connection). The jet assembly should not rotate because of an indexing pin
at the bottom.
1-5 CLEANING A NEW PUMP (Refer to Section 3, MAINTENANCE)
a. Read cold cap maintenance and installation data which will be found in Section III,
para. 3-4, of this manual. Remove the cold cap in accordance with these instructions.
b. Disassemble the internal jet system from the body of the pump. See Figure 1-3 for a section
drawing of a typical jet assembly.
c. Remove fill and drain plugs and gaskets if supplied.
d. Thoroughly clean all components of the jet assembly and pump casing interior (but not O-ring
gaskets) with acetone followed by an alcohol rinse.
e. Remove all traces of the cleaning fluid by carefully drying with clean, dry, oil-free compressed air.
WARNING
When lifting some Varian diffusion pumps, use power-assisted equip-
ment and trained moving/installation personnel to avoid dropping, slip-
ping, and/or overturning the pump and severely injuring personnel.
Check weight of equipment before lifting and do not stand under equip-
ment being moved.
Installation
1-6
Figure 1-3. Section Drawing – NHS-35 Diffusion Pump
Installation
1-7
f. For reassembly, reverse the above procedure.
g. Clean the flanges and O-ring grooves thoroughly with alcohol, using clean, lint-free rags.
WARNING
Diffusion pumps are typically cleaned with acetone, alcohol, or other
solvents.
When heated, sprayed or exposed to high temperature equipment,
these solvents become flammable and explosive, causing serious injury
or death. Do not use near a high-temperature source. Ventilate work-
ing area with a blower and use in large, well-ventilated room. When
heated or sprayed, solvents also become 4 to 5 times heavier than air
and will flow down, settling in tanks, pits, and low areas, thus displacing
air which can kill by asphyxiation. Use in a large, well-ventilated room.
Use of a self-contained breathing apparatus may be necessary.
Acetone, alcohol, and other solvents are irritants, narcotics, depres-
sants, and/or carcinogenics. Their inhalation and/or ingestion may pro-
duce serious effects. Prolonged or continued contact with the skin will
result in absorption through the skin and moderate toxicity. Always
ensure that cleaning operations are carried out in large, well-ventilated
rooms, and wear eyeshields, gloves, and protective clothing.
CAUTION
Acetone, alcohol, and other solvents degrade O-ring materials reducing
their ability to hold a vacuum. Do not use solvents on O-rings. If neces-
sary to clean O-rings, wipe with lint-free, clean cloth, wash in detergent
and water, or use a small amount of pump oil.
h. Remove all traces of acetone or alcohol by carefully drying with clean, dry, oil-free
compressed air. Install O-ring gasket.
Installation
1-8
1-6 UTILITY AND SYSTEM CONNECTIONS
1-6-1 Safety Considerations and Interlocks
a. Large pumps are equipped with two thermal switches. One is mounted at the body cooling
coils, the other at the center of the boiler plate (at the bottom of the pump).These thermal
switches are supplied normally closed. The thermal switches have been designed so that
a cooling water failure or low oil level in the boiler will result in an increase in temperature,
causing the normally closed contacts of the switches to open. When the problem has been
corrected and the temperature lowered, the thermal switch will automatically reset itself.
b. A small lamp of the same voltage as the diffusion pump heater may be connected across the ter-
minals of the thermal switch. The lamp will normally be shunted by the contacts. However, when
the contacts open, the lamp will receive full line voltage and give a visual trouble indication.
1-6-2 Vacuum Connections
a. The pump must be installed with the body vertical and plumb. Check that the mating flange on
the system (to the pump inlet) is horizontal within plus or minus 1 degree. If this condition is
not met, correct the system before installing the pump. The boiler of the pump (especially for
large pumps) must be horizontal to prevent uneven fluid level and avoid local overheating
where the fluid level would be too shallow.
b. Prepare inlet O-ring seals by wiping them with a clean cloth. Do not use solvents. Use a small
amount of diffusion pump oil to wet the cleaning cloth. Install the O-ring in the groove being
careful not to damage the sealing surface with cuts, nicks, or scratches.
c. Using appropriate lifting apparatus, align the bolt holes of the flanges and assemble the bolts.
Tighten the bolts evenly to compress the O-ring seal until light contact is achieved between
metal flanges.
d. Check fill and drain plugs for tightness. Apply light to medium torque, enough to compress
gaskets. Minute leaks through the gaskets may develop with use in this location. They may
be detectable with very sensitive mass spectrometer leak detectors.
1-6-3 Cooling Water Connections (See Figure 1-4)
The following method of external connections is recommended.
a. Water connections are designed for 3⁄8FPT fittings. The cold cap cooling coil and all of the
body and foreline cooling should be connected in series. A cooling water supply of 3 to
4 gpm at 60°F to 80°F (16°C to 27°C) should be adequate. A higher flow than this will not
be harmful. If the pump is to be operated continuously at pressures below 1 x 10-6 Torr, the
cooling coil on the bend of the foreline may be bypassed. This surface will then operate hot
and therefore provide additional degassing.
WARNING
_____________
Utility failure can cause damage to the equipment, overheating, and
possible explosions. Designers of the equipment using diffusion pumps
must design their system to protect personnel and property from possi-
ble hazards.
Installation
1-9
Water Requirements
4 gallons per minute at 60° to 80°F inlet temperature pressure
drop across series curcuit of cold trap and body – 40 PSI.
Figure 1-4. Water Cooling Connections
If the water supply pressure is low, it may be necessary to connect the different sections of
cooling coils in parallel. This should be done if the cooling water discharge temperature
exceeds 130°F (54°C). The cooling water discharge should, if possible, be connected to an
open drain so that cooling water flow can readily be checked.
b. If the quick-cool coil is required, it must be connected to an open drain and the feed line con-
trolled by a separate water 3-way valve (open, closed, and vent to atmosphere).The drain
must be below the boiler level so that it is drained completely when the quick-cool coil water
supply is shut off and the pump is operating.
1-6-4 Electrical Connections (See Figure 1-5, 1-6, or 1-7, Diffusion Pump Wiring Diagram)
a. The pump heater has been designed to operate at a certain voltage. Check the heater for
correct supply voltage and, in the case of multiphase connections, for load balance by
measuring the resistance of each branch. (See page 1-10, 1-11, 1-12 for proper resistance.)
WARNING
_____________
High voltages (up to 480V) can kill. Always break the primary circuit to
the pump before starting to work on the heater and/or its wiring.
Installation
1-10
Figure 1-5. 240/400/440V Wiring Diagram – NHS-35 Diffusion Pump
Installation
1-11
Figure 1-6. 380/415V Wiring Diagram – NHS-35 Diffusion Pump
Installation
1-12
Figure 1-7. 480V Wiring Diagram – NHS-35 Diffusion Pump
Installation
1-13
b. Make connections to the terminals in the junction box (at the foreline).The use of flexible
conduit is recommended to facilitate removal of the pump for service. The pump should not
be operated at more than 5% over the rated voltage. Make connections in accordance with
the wiring diagram provided with each pump.
1-6-5 Thermal Switches
The thermal switches have been pre-set at the factory and should not require adjustment. The lower
thermal switch is set at 600°F; the upper switch is set at 200°F. Should any thermal switch be thrown
out of adjustment, it can be adjusted as follows:
1. Boiler thermal switch
The boiler thermal switch is mounted on a brass block at the center of the boiler.
The thermal switch should be adjusted, with the pump operating, as follows:
a) After several hours operation, disconnect the lead wires and place an ohmmeter
across the terminals of the thermal switch.
b) Turn the adjusting screw until 1⁄16 of a turn either way will make the contact open
or close.
c) Turn the adjusting screw clockwise 1⁄4turn.
2. Cooling water thermal switch
The cooling water thermal switch is located inside the small junction box. The switch should
be adjusted with the pump in operation as follows:
a) Disconnect the lead wires and place an ohmmeter across the terminals of
the switch.
b) Turn the switch adjusting screw until 1⁄16 of a turn either way will make the
contact open or close.
c) Turn the adjusting screw clockwise 1⁄4turn.
Thermal switches are to be operated on AC power only and should be connected in series
with the coil of the diffusion pump heater contactor. See Figures 1-5, 1-6, or 1-7, Diffusion
Pump Wiring Diagram.
1-6-6 Initial Vacuum Test
The purpose of this test is to establish the leak tightness of the system, specifically the vacuum connec-
tions to the diffusion pump. (To eliminate misleading indications and the masking of leaks by the fluid, the
tests should be carried out with the diffusion pump “dry”, i.e., before it is charged with the pumping fluid.)
WARNING
_____________
Pumps and their components are designed for vacuum service; they
are not designed to be pressurized which could cause them to burst
possibly expelling shrapnel at lethal velocities. Serious accidents have
been caused by intentional pressurization of vacuum systems and their
components. Never pressurize any part of a vacuum system for test
or any other purpose. Always provide pressure relief when designing
diffusion pumps into systems and ensure that pressure relief motion is
limited to safe envelopes.
Installation
1-14
a Confirm the vacuum ultimate pressure characteristics of the mechanical pump. This should
closely approximate the value quoted in the manufacturer’s data, if the mechanical pump is
correctly installed, adjusted, and filled with clean oil. Pressure measurements should be made
with a continuously indicating total pressure gauge, such as a thermocouple gauge. This test
can be performed to evaluate either valved or unvalved systems. Connect the outlet or foreline
of the diffusion pump to the inlet of the mechanical backing pump, using appropriate vacuum-
tight connections.
b In the case of a valved system, close the roughing valve and main isolation valve ahead of
the diffusion pump. In the case of unvalved systems, the entire work chamber volume must
be included in the test. Evacuate the entire system with the mechanical pump only. Let the
mechanical pump reach an ultimate pressure in the system. This reading should approximate
the value obtained in step a above (usually 10 to 50 microns (1.33 to 6.65 Pa)). If it does not,
examine for leakage. If leakage is suspected, follow standard procedures for leak testing.
These will depend on the type of vacuum gauges and/or leak detection equipment available.
The most effective are Varian’s helium leak detectors.
1-7 ADDING PUMP FLUID
a. The recommended fluid charge for the pump is three gallons. The fluid charge will gradually
be depleted through use, but the pump will continue to operate normally. When the charge is
reduced to approximately 60% of the initial amount, the boiler temperature may begin to rise
and under this condition the thermal switch is designed to open the heater circuit.
b. This diffusion pump is furnished with fill and drain fittings with special Viton elastomer
sealed plugs.
WARNING
_____________
The risk of explosion in large pumps is increased by hydrocarbon oils,
low fuel levels, or opening either fill or drain plugs during operation.
Never operate diffusion pumps larger than 6 inches with hydrocarbon
oils without a complete safety analysis for the specific system and appli-
cation. Hydrocarbon oils are more prone to explode than synthetic sili-
cone-based oils, similarly the larger the diffusion pump the greater the
risk of explosion. Running the pump with low oil level causes hot sur-
faces and the oil to be decomposed and very toxic. Such decomposed
oil and any residue from toxic/corrosive materials pumped will be pre-
sent on the dipstick when the fluid level is measured.
NOTE
________
Fluids must be stored in clean, tightly closed containers and should be
clearly identified in accordance with their type. Do not mix pumping flu-
ids of different types and origins. Generally, it is not a good idea to mix
used and new fluid for a pump charge.
Installation
1-15
c. If the pump is hot, wait until the pump has cooled then vent it to atmosphere. Remove the
plug from the filling port of the pump and install the specified quantity of fluid up to the
FULL COLD level indicator on the sight glass (see Figure 1-8).The fluid can also be
poured in from the pump inlet or foreline.
d. Replace the fill plug with a new Viton gasket.Tighten the fill plug using moderate torque
(75 inch-pounds maximum). Lubricate the O-ring with pump fluid before installation.
e. Once the pump is running, the oil level should be in the FULL HOT operating range as
indicated on the sight glass assembly.
f. It is not recommended that Santovac 5 Diffusion Pump Fluid be used with the NHS-35.
Figure 1-8. Sight Glass Assembly
Installation
1-16
2-1
SECTION II
OPERATION
During initial installation, the newly installed pump fluid may be subjected to a degassing process. This
may result in foreline pressure fluctuations and “bursts”. Such fluctuations are considered normal.
2-1 START-UP PROCEDURE
a. Evacuate the diffusion pump by means of the mechanical roughing pump to a pressure level
below 0.5 Torr (66.5 Pa).The diffusion pump will not function unless the discharge pressure is
less than the tolerable forepressure (approximately 0.5 Torr (66.5 Pa)).
b. Turn on the cooling water supply to the pump body and check that adequate flow is provided
by examining the amount of water discharged at the visual drain points.
WARNING
_____________
The following conditions increase the risk of explosion:
• any air leaks into the system;
• roughing through a hot diffusion pump may cause some hot hydrocar-
bon fluids to ignite or explode when exposed to air;
• air release or admitting air to a pump with a hot boiler, permit a strong
oxidizer to contact the hot pump oil;
• high (above 1 micron (.133 Pa)) inlet pressure;
• insufficient (or low level of) pump fluid;
• running pump without cooling water circulating to main water cooling
coils;
• trapping water between closed isolation valves at inlet and discharge
of quick cool coils and running diffusion pump;
• foreign matter in the pumping fluid which changes its viscosity and
obstructs flow passages.
CAUTION
________
• Do not turn on the heater without fluid in the pump. This may ruin the
heaters and damage the pump.
• Do not air-release the pump while the boiler is hot. Most diffusion
pump fluids are heat-sensitive and will break down under these con-
ditions.
• Do not operate the pump without the foreline baffle. This may cause a
greater than normal fluid loss.
• Do not operate the pump for extended periods at an inlet pressure
above 1 micron (.133 Pa). High pressure operation may cause exces-
sive backstreaming.
• Do not operate the pump heater unless the cooling water is circulating.
It will cause the pump and fluid to overheat.
Operation
c. Switch on the power to the diffusion pump heater.
d. Check inlet and forepressure performance by means of the system instrumentation.
e. During operation, the gas load at the inlet of the diffusion pump should not exceed the
maximum throughput capability of the pump. This means that the pressure at the inlet flange
should not (except in transient conditions) exceed approximately 1 x 10-4 Torr .0133 Pa.
During operation, the discharge or fore pressure must be below the specified tolerable
forepressure.
2-2 SHUTDOWN PROCEDURE
2-2
a. Switch off the power to the diffusion pump heaters.
b. Admit cooling water to the quick-cool coil if necessary and continue to circulate it until the
pump body just above the boiler heat shield can be touched (approximately 130°F or 54°C).
In valved systems which have tight inlet and foreline connections, it is possible to close valves
to isolate the diffusion pump at inlet and discharge, to air-release the remainder of the
system, shut off the heat to the diffusion pump, and stop the mechanical pump. With this
method, the quick-cool coil does not have to be used. However, the water flow through the
pump must be maintained until the boiler cools down below approximately 300°F (150°C).
WARNING
_____________
Boiler temperatures reach 530°F (275°C) which can cause serious
burns when touched. Always ensure surfaces have cooled near room
temperature before touching them.
Air release or admitting air to a pump with a hot boiler, especially when
it is under vacuum, permits a strong oxidizer to contact the hot pump oil
and thereby increases the risk of an explosion.
CAUTION
________
Do not operate the quick-cool coil when the pump is c old or out of ser-
vice to prevent harmful collection of condensation on the boiler plate,
heater, and heater terminals.
3-1
SECTION III
MAINTENANCE
3-1 GENERAL
Diffusion pumps generally require little attention when correctly operated. However, it is advisable to
perform some periodic checks to insure continued trouble-free operation. By simple preventive main-
tenance, costly down-time and cleaning procedures can be avoided. A day-to-day log of pump and
system performance will indicate the condition of the pump and marked variations will show the need
for corrective action.
3-2 PERIODIC INSPECTION
The frequency of inspection will depend on the type of system, its operation and utilization. The maxi-
mum interval between inspections is established on the basis of experience. It is recommended that
the following items be regularly examined.
a. When the pump is cold, check the condition and level of fluid. These can be inspected by
withdrawing a sample through the drain and by visually checking the level of fluid through the
sight glass respectively. (Use new O-ring gaskets when replacing fill and drain plugs.) Slight
discoloration of the fluid does not affect performance.
b. Loss of the fluid can be caused by the following:
1. incorrect air admittance procedures and/or admittance of excessive air or other gas
to a hot pump,
2. inadequate water cooling
3. continuous operation at inlet pressures above 10-3 Torr (.133 Pa)
4. failure to reinsert the foreline baffle in the pump assembly
c. When the pump is cold, check that the heaters are bolted snugly to the boiler plate and that
all heater terminal connections are tightly fastened inside the junction box.
WARNING
_____________
High voltages (up to 480V) can kill. Always break the primary circuits to
the power supply before starting to work on the heater and/or its wiring.
Make sure that the pump is at room temperature before attempting ser-
vice. Serious burns can result if this Warning is not heeded.
Depending on system process, poisonous or corrosive compounds may
be present when opening the fill or drain. Always wear appropriate
gloves and clothing and use a self-contained breathing apparatus.
An explosion could occur if the fill or drain is opened when the pump is
running or when it is hot. Check oil level only when the pump is cold.
Maintenance
3-2
d. Check the total heater input and balance of load if a multi-phase heater is used.
e. Check to insure that cooling water flow is unobstructed and not below specified quantities.
3-3 CLEANING
Complete cleaning of the pump may be periodically required because of the gradual deterioration of
some pump fluids. Removal of the pump from the system is then necessary.
a. Disconnect all water cooling lines and break the primary circuit supplying power to the
pump heater.
b. Unbolt the inlet and foreline connections and remove the pump from the system.
c. Drain the pump of all fluid.
d. Remove the jet assembly following the procedures outlined.
WARNING
_____________
If hazardous gas, vapors, chemicals, or combustible mixtures are
pumped, sufficient quantities may exist during operation. This pump
may contain decomposed and/or overheated pump oils or poisonous
and/or corrosive process materials which are highly toxic and also can
be an asphyxiant. Proper operation will not always ensure that all haz-
ardous materials have been removed.
Diffusion pumps are typically cleaned with acetone, alcohol, or other
solvents.
When heated, sprayed or exposed to high temperature equipment,
these solvents become flammable and explosive, causing serious injury
or death. Do not use near a high-temperature source. Ventilate work-
ing area with a blower and use in large, well-ventilated room. When
heated or sprayed, solvents also become 4 to 5 times heavier than air
and will flow down, settling in tanks, pits, and low areas, thus displacing
air which can kill by asphyxiation. Use in a large, well-ventilated room.
Use of a self-contained breathing apparatus may be necessary.
Acetone, alcohol, and other solvents are irritants, narcotics, depres-
sants, and/or carcinogenics. Their inhalation and/or ingestion may pro-
duce serious effects. Prolonged or continued contact with the skin will
result in absorption through the skin and moderate toxicity. Always
ensure that cleaning operations are carried out in large, well-ventilated
rooms, and wear eyeshields, gloves, and protective clothing.
CAUTION
________
Any solvents degrade O-ring materials reducing their ability to hold a vac-
uum. Do not use solvents on O-rings. If necessary to clean O-rings, wipe
with a lint-free, clean cloth or use a small amount of diffusion pump oil.
Maintenance
3-3
e. Thoroughly clean the pump body interior using acetone followed by an alcohol rinse. Dry
with clean, dry, oil-free compressd air or heat gun.
f. Thoroughly clean the jet assembly using acetone, wipe all surfaces with alcohol, and dry
with clean, dry, oil-free compressed air or heat gun.
g. Install the jet in the pump body.
h. Check condition of O-rings and replace, if necessary.
i. Reinstall the pump in the system.
3-4 DISASSEMBLING AND REASSEMBLING THE COLD CAP
1 To disassemble the cold cap:
a Remove the female coupling, nut, follower, and the gasket located at the end of the
cold cap water line on the outside of the pump.
b Remove the nut which secures the cold cap to the jet assembly.
c Lift out the cold cap.
2 To reassemble the cold cap:
a Insert the end of the cold cap water line into the cold cap port opening at the side of
the pump before setting the cold cap on top of the jet assembly.
b Replace the nut which secures the cold cap to the jet assembly. Do not overtighten
the nut.
c Replace the gasket, the follower, the nut, and the female coupling to the side of
the pump.
Figure 3-1. Heater Element Assembly
Maintenance
3-4
3-5 DISASSEMBLING AND REASSEMBLING THE JET ASSEMBLY
1 To disassemble the jet assembly:
a Disassemble the cold cap water line feedthrough compression seals by removing the
nut, follower, gasket, and female coupling located at the side of the pump.
b Remove the nut which secures the cold cap to the jet assembly.
c Lift out the cold cap.
d Unscrew the hex nut above the top cap and remove it.
e Lift the jet assembly out with a chain fall attached to the cross member now visible in
the jet.
f Once the jet is out of the pump, unscrew the two nuts on the cross member to release
the lower jet stages.
g Disassemble and clean as required.
2. To assemble the jet assembly:
a Reverse the steps outlined above.
b When the jet is installed in the pump body, it is very important that the slot in the jet
base is engaged in the locating pin in the boiler. Unless this is done, the pump will not
function properly.
3-6 HEATER REPLACEMENT
a Determine which heater element has failed at the junction box, then disconnect the two
corresponding leads from the terminal strip. Pull the leads out of the terminal box then out
the elbow cover plate.
b Remove the heater cover and insulation from the bottom of the diffusion pump.
c Remove the nuts holding the clamping plate.
d Lower the entire heating unit (heater element, clamping plate and heater shield, see
Figure 3-2) until it is off the mounting studs.
WARNING
_____________
High voltages (up to 480V) can kill. Always break the primary circuit to
the power supply before starting to work on the heater and/or its wiring.
CAUTION
________
Poor clamping resulting in inadequate thermal contact may result in
reduced heater life and poor pump performance. Tighten nuts finger-
tight on clamping plate, then gradually and evenly tighten them to 250
in-pounds.
Maintenance
3-5
e Coat the boiler studs with anti-seize compound such as FEL-PRO-C-5A or common milk
of magnesia.
f Assemble the new unit (heater element, clamping plate, and heater shield).
g. Support the heating unit by the clamping plate, line up the holes with the boiler studs, and
push the unit up against the boiler plate. Use two nuts finger-tight to hold it in place.
h. Screw on the remainder of the nuts finger-tight, then tighten the nuts evenly up to 250 inch-
pounds of torque.
i Label the heater leads according to the schematic diagram, then run the wires around the
periphery of the pump, under the wire retaining clips, into the conduit, and up into the junction
box. Connect the leads to the terminal strip then replace the elbow cover plate.
j Replace the heater cover and insulation.
Figure 3-2. External Fittings – Cold Cap Assembly
CAUTION
________
Should it be necessary to use a new wire in the following step, it is
important that no. 10 stranded nickel wire with high-temperature insula-
tion is used. The terminal lugs must be solid nickel. If copper or copper-
plated wire and/or lugs are used, they will oxidize rapidly because of the
high temperature and the terminals will overheat and fail.
3-7 REPLACEABLE PARTS
The following is a list of replaceable parts for the Varian NHS-35 Diffusion Pump.
Part Number Description
81437301 Cold cap assembly (includes No.10-32 SST Rd Hd screw and
No. 10-32 hex nut) SST
660811494 Cold cap gasket (see Figure 3-2)
F2622001 Cold cap follower (brass)
75786001 Cold cap nut
622445026 Cold cap female coupling, 1⁄2-inch OD tube x 3⁄8-inch FPT,
Imperial Flexfitting No. 66-FL
F1971302 Jet Assembly
F1744301 Foreline baffle assembly
F6097301 Sight glass service kit (includes glass tube, O-rings, and fittings;
valves not included) (for pumps built prior to October 1995)
77261001 Threaded plug, fill and drain
K9050005 Upper thermal switch, 200°F
K9050006 Lower thermal switch, 600°F
647335010 Heater element with leads (4000 W, 240V, 380V, 480V)
L6383010 Heater element with leads (4000 W, 400V)
L6383011 Heater element with leads (4000 W, 440V)
F1749001 Clamping plate (no crushplate in NHS-35)
L6514001 Insulation for heaters – Cerablanket 0.50 inch thick
L9223001 Sight glass (for pumps built after October 1995)
K0377169 O-ring kit; includes:
1 butyl inlet flange O-ring (78536001)
1 butyl foreline flange O-ring (2-267)
8 Viton fill and drain O-rings (2-213)
1 Sight glass O-ring (2-240)
1 Graphite sight glass gasket (L9228001)
4 O-ring Viton (2-221)
695472008 DC-702 diffusion pump fluid (one-gallon container)
695474008 DC-704 diffusion pump fluid (one-gallon container)
695475008 DC-705 diffusion pump fluid (one-gallon container)
78536002 O-ring for ISO inlet flange
Maintenance
3-6
4-1
SECTION IV
TROUBLESHOOTING
4-1 LEAKAGE
Analysis of general operational experience with diffusion pumps indicates that certain locations are
more prone to the incidence of leaks. The following locations should be checked first if leakage is the
suspected cause of poor system performance.
a. Inlet and foreline connections.
b. Drain and fill plugs.
c. Other compression fittings, such as high-vacuum gauges in the system.
d. Threaded connections, such as a foreline gauge.
4-2 OUTGASSING
High-vacuum systems, even without external leakage, can have high gas loads due to outgassing
from internal surfaces or processes. The pressure in the system is a result of gas load divided by
pumping speed (p = Q/S). If the gas load (Q) exceeds the maximum throughput capability of the diffu-
sion pump, the diffusion pump will not function and the pumping action will essentially be due to the
mechanical backing pump.
To estimate the gas load, isolate the system from all pumps after evacuation and measure the rate of
pressure increase.The gas load can be estimated as follows:
V x ∆P
Q=______
∆t
where V is the isolated volume, ∆P is the pressure rise, and ∆t time period of measurement.
4-3 POOR PUMP OR SYSTEM PERFORMANCE
Before proceeding with a program of step-by-step troubleshooting, check the performance and accu-
racy of the vacuum gauges used on the system. Table 4-1 shows common faults, and lists the proba-
ble cause and corrective actions to correct for poor performance.
Troubleshooting
4-2
Table 4-1
Fault Probable Cause Corrective Action
Poor system pressure Leaks in system, virtual or real Locate and repair.
High process gas load Measure gas load, eliminate
cause.
System dirty Clean system to reduce
outgassing.
Poor ultimate pressure Contaminated pump fluid Examine and replace.
Low heat input Check voltage. Check for conti-
nuity, burned-out element, poor
thermal contact.
Inadequate cooling water flow Check water pressure. Check
tubing for obstructions and
backpressure.
Excessive or too cold cooling water Check temperature. Adjust
flow.
High forepressure Check for leak in foreline, poor
mechanical pump performance,
breakdown of mechanical
pump fluid.
Water in quick-cool coil Check and remove cause.
Low heat input Check heaters.
Low fluid level Add fluid.
Malfunctioning pump assembly. Check and repair or replace.
Improperly located jets. Damaged
jet system.
Inlet pressure surges Incorrect heater input Check and correct.
Fluid outgassing Condition fluid by operating the
pump for a few hours.
Leak in system ahead of pump inlet Check and correct.
High chamber Forepressure too high Check for leak in foreline, poor
contamination mechanical pump performance,
breakdown of pump fluid, and
incorrect valve operation.
Prolonged operation at high through- Review procedures.
put at pressure above 10-3 Torr
Improper system operation and Review procedures.
air release procedures
Pump will not start Safety circuits and/or protective Check utilities, flow switches,
devices prevent contactor from interlocks. Check thermostat
staying closed operation.
Low speed (prolonged-
cycle after checking
gas load conditions)
Health and Safety Clearance
Return Authorization Policy
In compliance with Federal OSHA Safety Standard 1910.1200, Hazard Communications “Right to
Know”, Varian is enforcing that standard to preclude the potential health risk to its service person-
nel that can occur when receiving, disassembling, or repairing potentially contaminated products.
Returned products not accompanied by this completed certificate will be held until the completed
certificate is received; failure to provide this completed certificate within 30 days of notification
will result in the return of held product(s) unprocessed.
If a product is received at Varian in a contaminated condition, the customer will be held respon-
sible for all costs incurred to ensure the safe handling of the product.
Company Name:
__________ Hereby certify that the product(s) listed below have been cleaned of all hazardous
residue and that the residue remaining is of a non-hazardous nature.
__________ Hereby certify that the product(s) listed below have been contaminated by the fol-
lowing toxic or hazardous materials:
RA Number Model Number Serial Number
________________________ ______________________ ______________________
________________________________________ _______________________________ ___________
Authorized Signature Title Date
Note: Varian Service will only accept contaminated Turbo or Mechanical Pumps. All other
products must be decontaminated by the customer before Varian Vacuum Products
Lexington will assign a Return Authorization (RA) number and authorize the return of
the product (refer to the attached Return Authorization Report on the next page).
Note:Varian Vacuum Products Lexington cannot accept any biological hazards,
radioactive material, organic metals, or mercury at its facility.
Varian Vacuum Technologies
21 Hartwell Avenue
Lexington Massachusetts 02421
Telephone (781) 861-7200
FAX (781) 860-5405
November 1995
Returned Material Report
This report must accompany all products returned for repair, replacement, or warranty evaluation. Full informa-
tion regarding reasons for return of the product will expedite repair or adjustment. Please fill in all blanks below
and furnish any other information which will help identify the nature and cause of failure.
Reason for Return (check appropriate box)
❒Paid Repair ❒Advance Exchange ❒Shipping Error ❒Credit
❒Warranty Evaluation ❒Loaner Return ❒Shipping Damage
Product Information (use separate forms if more than one model no.)
Varian Model No. _______________________ Serial No. __________________ Quantity ___________________
Part Description
Purchase Information (if product is being returned for warranty evaluation, show your original purchase order
number and date purchased)
Varian Sales Order No. (if available) ________________________ Machine # ___________________________
Original Purchase Order No. _________________________ Purchase Order Date _______________________
Company Name ___________________________________________ Contact _______________________________________
Address
City ______________________________________________________________ State _________________ Zip _____________
Telephone
Failure Report (describe in detail suspected cause or nature of malfunction)
Returned Products
All products returned to Varian/VPD Service Operation for warranty evaluation must be sent prepaid and
customer must comply with the warranty replacement and adjustment provision set forth in the warranty.
Ship directly to: Varian Vacuum Products
Vacuum Products Service Center
121 Hartwell Avenue
Lexington, MA 02421
All products sold by Varian and returned by customer are subject to Varian Vacuum Products standard
terms and conditions of sale including, but not limited to, the warranty and damages and liability provi-
sions set forth in the warranty.
November 1995
VPD Service Operation
