Edwards nHT10 User manual

Diusion Pumps
nHT
INSTRUCTION MANUAL
B31430880_C Original instrucons
edwardsvacuum.com

Copyright noce
©Edwards Limited 2020. All rights reserved.
Trademark credit
Edwards and the Edwards logo are trademarks of Edwards Limited, Innovaon Drive,
Burgess Hill, West Sussex RH15 9TW.
Disclaimer
The content of this manual may change from me to me without noce. We accept
no liability for any errors that may appear in this manual nor do we make any
expressed or implied warranes regarding the content. As far as praccal we have
ensured that the products have been designed and constructed to be safe and without
risks when properly installed and used in accordance with their operang instrucons.
We accept no liability for loss of prot, loss of market or any other indirect or
consequenal loss whatsoever.
Product warranty and limit of liability are dealt with in our standard terms and
condions of sale or negoated contract under which this document is supplied.
You must use this product as described in this manual. Read the manual before you
install, operate, or maintain the product.

Declaration of Conformity
This product has been manufactured under a quality management system certified to ISO 9001:2015.
This declaration is based on the requirements of EN ISO 17050-1 and the relevant directives.
P200101199B
Edwards Ltd,
Innovation Drive,
Burgess Hill,
West Sussex,
RH15 9TW, UK
The following product:
Vapour Diffusion Pumps:
nHT10: B31130400 / B31130460 / B31132400 / B31132460
nHT16: B31230400 / B31230460 / B31232400 / B31232460
nHT20: B31430400 / B31430460 / B31432400 / B31432460
nHT35: B31530400 / B31530460 / B31532400 / B31532460
conform to the relevant requirements of European CE legislation:
EN 1012-2:1996+A1:2009 Compressors and vacuum pumps - Safety requirements
Part 2: Vacuum pumps
EN 60204-1:2006 Safety of machinery - Electrical equipment of machines
Part1: General requirements
EN 61000-6-2:2005/AC:2005 Electromagnetic compatibility (EMC) –
Part 6-2: Generic standards - Immunity for industrial environments
EN 61000-6-4:2007/A1:2011 Electromagnetic compatibility (EMC) –
Part 6-4: Generic standards - Emission standard for industrial environments
And fulfils all relevant provisions of
2006/42/EC Machinery Directive
The safety objectives of the Low Voltage Directive 2014/35/EU were complied with in accordance with
Appendix 1 No. 1.5.1 of Machinery Directive 2006/42/EC
2014/30/EU Electromagnetic Compatibility (EMC) Directive
Note: This declaration covers all product serial numbers from the date this Declaration was signed onwards.
Cologne, February 11th, 2019 Cologne, February 11th, 2019
___________________________ __________________________
Andries Desiron i.V. Martin Laerbusch
VP Engineering Head of Production Systems
Industrial Vacuum Cologne Product Company

Contents
1. Safety and compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 Denion of Warnings and Cauons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Safety symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2. Important safety informaon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Mechanical hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Electrical hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Thermal hazards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4 Danger through substances and materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3. Descripon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1 Design and funcon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Supplied equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4. Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1 Dimension drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Pumping speed curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.3 Ordering informaon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.4 Centre of gravity overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.5 Pump uids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5. Transport and storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.1 Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6. Installaon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1 Inlet connecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2 Backing connecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.3 Coolant connecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.4 Electrical connecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.5 Connecng the heaters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.5.1 Terminal box layouts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.5.2 Thermal safety switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6.5.3 Connecng monitoring components (oponal). . . . . . . . . . . . . . . . . 38
6.6 Pump uid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7. Operaon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.1 Media compability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.2 Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7.3 Operate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
7.3.1 Air inrush. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
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7.3.2 Regular checks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
7.4 Turn o/shut down. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
7.5 Disconnect the pump from the system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
8. Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.1 Check the pump uid level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.2 Top-up pump uid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.3 Exchange the pump uid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.4 Clean the pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8.5 Clean the cooling coils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.6 Replace the heang cartridges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9. Fault nding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
10. Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
11. Waste disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
11.1 Disposing of used uid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
12. Spares and accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
13. Terminal and circuit diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
14. Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
14.1 Return the equipment or components for service . . . . . . . . . . . . . . . . . . . . 76
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List of Figures
Figure 1: Overview of nHT diusion pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 2: nHT10 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 3: nHT16 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 4: nHT20 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 5: nHT32 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 6: nHT35 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 7: Pumping speed overview for nHT10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 8: Pumping speed overview for nHT16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 9: Pumping speed overview for nHT20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 10: Pumping speed overview for nHT32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 11: Pumping speed overview for nHT35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 12: nHT pump shipping case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 13: Connecon elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 14: nHT10 terminal box layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 15: nHT16 terminal box layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 16: nHT20 terminal box layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 17: nHT32/35 terminal box layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 18: Schemac for a diusion-type vacuum pump system. . . . . . . . . . . . . . . . . . . . . 40
Figure 19: Commission and operaon schemac. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 20: Checking the level of the pump uid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Figure 21: Oil level sight glass with pump uid inlet and outlet ports. . . . . . . . . . . . . . . . . 50
Figure 22: Overall view of the nHT20 ANSI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 23: nHT10 Circuit diagram (1 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Figure 24: nHT10 Circuit diagram (2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Figure 25: nHT16 Circuit diagram (1 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Figure 26: nHT16 Circuit diagram (2 of 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 27: nHT20 Circuit diagram (1 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Figure 28: nHT20 Circuit diagram (2 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Figure 29: nHT20 Circuit diagram (3 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Figure 30: nHT32/35 Circuit diagram (1 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Figure 31: nHT32/35 Circuit diagram (2 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 32: nHT32/35 Circuit diagram (3 of 3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
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1. Safety and compliance
1.1 Denion of Warnings and Cauons
NOTICE:
For safe operaon from the start, read these instrucons carefully before you install
or commission the equipment and keep them safe for future use.
Read all the safety instrucons in this secon and the rest of this manual carefully
and make sure that you obey these instrucons. The equipment must only be
operated and maintained by trained personnel in the proper condion and as
described in this instrucon manual.
Obey local and state requirements and regulaons. If you have any quesons about
safety, operaon or maintenance of the device, please contact our nearest subsidiary.
Important safety informaon is highlighted as warning and cauon instrucons. Obey
these instrucons.
WARNING:
If you do not obey a warning, there is a risk of injury or death. Dierent symbols are
used according to the type of hazard.
CAUTION:
If you do not obey a cauon, there is a risk of minor injury, damage to equipment,
related equipment or process.
NOTICE:
Informaon about properes or instrucons for an acon which, if ignored, will
cause damage to the pump or the system.
We reserve the right to change the design and the stated data. The illustraons are not
binding.
Keep the instrucons for future use.
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B31430880_C - Safety and compliance

1.2 Safety symbols
The safety symbols on the products shows the areas where care and aenon is
necessary.
The safety symbols that follow are used on the product or in the product
documentaon.
Warning/Cauon
An appropriate safety instrucon must be followed or cauon to a po-
tenal hazard exists.
Warning - Heavy object
Idenes a possible hazard from a heavy object.
Warning - Dangerous voltage
Idenes possible hazards from dangerous voltages.
Warning - Hot surfaces
Idenes a potenal hazard from a hot surface.
Warning - Use protecve equipment
Use appropriate protecve equipment for the task.
Warning - Risk of explosion
There is a risk of explosion when you do the task.
Warning - Toxic material
The material is toxic.
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B31430880_C - Safety and compliance

2. Important safety informaon
2.1 Mechanical hazards
WARNING: HIGH PRESSURE
Ejecon of parts through bursng of the vacuum system due to excessive pressure,
caused by errors like malfuncon at the gas inlet into the vacuum system.
The pump must be securely anchored during operaon.
The pump may be vented only if the pump uid temperature is < 100 °C, otherwise
there is a risk of explosion.
Reverse venng must be ruled out. The cooled pump should be vented from the high
vacuum side.
Turn o the cooling water supply only aer the pump has cooled down to < 100 °C.
Pump operaon with a closed inlet and outlet and an isolated cooling water supply is
a dangerous condion and must be prevented (for example, by an interlock circuit).
WARNING: HEAVY OBJECT
Loss of stability during transport.
Uncontrolled movement through incorrect fastening or raising or liing of the pump
system.
Use all liing eyes when moving the pump body. Pay aenon to the centre of
gravity.
Transportaon anges (blank anges) and the supplied clamps may be used only for
transportaon purposes; they are not suitable for the assembly of the pumps in
systems.
Uncontrolled movement through inera of mobile pump systems (wheels or mobile
frame). Mount and move mobile pumps with wheels only on at, solid, horizontal
surfaces.
Move the pump at slow speed.
CAUTION: EXPOSURE TO VACUUM
Risk of injury. Do not operate the pump system with open inlet and outlet ports.
During installaon connect the system mechanically via the inlets and outlets before
making the electrical connecons.
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B31430880_C - Important safety informaon

CAUTION: EJECTION OF PARTS
Ejecon of parts through implosion of a part of the pump or the pump system.
If the boiler overheats as a result of lile or no oil or low cooling water ow, the
boiler can implode.
The water cooling system must not be interrupted if a fault occurs. Observe the
installaon regulaons.
CAUTION: OIL LEAKAGE
Slip, trip or fall hazard due to oil leakage from the pump.
Depending on the work process, oil may leak from the pump.
Check the pump for any oil that has leaked. Take appropriate measures.
CAUTION: AUTOMATIC RESTART
Hazards that may occur through independent restart of a pump aer a shut down
due to an error.
Connect the pump in such a way that if a monitoring element is triggered
(thermostat, thermal protecve switch, water ow guard) it does not automacally
restart aer the fault condion has ended.
2.2 Electrical hazards
WARNING: HAZARDOUS VOLTAGE
Electric shock through direct or indirect contact of live parts.
Electric shock by touching acve electrical components.
The electrical connecon must be carried out by a trained person.
Observe the naonal regulaons in the country of the user, for example, for Europe
EN 50110-1.
A protecve earth check between the PE connecon and every touchable part that
requires a protecve connecon, must be carried out before inial operaon. Do this
for the test current, use 10 A d.c. or a.c. (RMS), while not more than 0.1 Ω
impedance.
The temperature sensor (Pt 100) which is built into one of the heang cartridges may
become live in a heater fault condion. The operator must take suitable precauons
for protecon against inadvertent contact. For example, a temperature transducer
with double or reinforced insulaon can be used for this purpose.
Connect a second protecve earthing conductor.
There are hazardous voltages present on the mains cables (danger to life).
Before you do maintenance or service work on the product, turn o the mains
supply.
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B31430880_C - Important safety informaon

WARNING: LOSS OF POWER SUPPLY
Explosion hazard due to uncontrolled venng.
If ed, an inlet valve must close in the event of a power failure.
Air inltraon into an operaon ready, warm diusion pump is a dangerous
condion and must be reliably ruled out.
If electro-pneumacally operated inlet and outlet vacuum valves are used, these
must be “normally closed” when in a “de-energised” or “unpressurised” condion.
Also for these valves, the venlaon of a ready-to-operate, hot diusion pump must
be prevented through appropriate interlock circuits.
The components must be connected correctly. Electrical safety tests, in parcular the
insulaon and protecve grounding conductor examinaon, must be done.
CAUTION: MOISTURE ABSORPTION
High electrical fault currents due to moisture absorpon by mineral insulang
material of the heang elements.
The hygroscopic insulaon of the heang element could lead to a burn-out of the
heater cartridge. Risk occurs through longer shut o cycles and humid ambient
condions.
Take note of the installaon instrucons for the replacement and connecon of the
heater cartridge.
Check stock before changing/inserng (measured value: 49 to 55 Ω) and degas if
necessary.
Check heaters if they have not been used for more than 1 year.
2.3 Thermal hazards
WARNING: HOT SURFACES
Burns from touching hot surfaces.
Burning of ngers, hands, arms on hot surfaces up to +140 °C. Hazard of burns with
open covers.
Handle the pump only in vented and cooled condion. Wear suitable protecve
equipment. Take note of the cooling me aer switching o.
WARNING: HOT SURFACES
Scalding by touching hot equipment or lubricants.
Risk of scalding when opening the hot pump through pump uid vapour.
Only open uid drain port or ll port if the pump is cooled down to room
temperature and is vented.
Let cooling water pipes cool down before removing and then shut o the feed line.
Wear suitable protecve equipment.
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B31430880_C - Important safety informaon

2.4 Danger through substances and materials
WARNING: TOXIC SUBSTANCES
Danger through expulsion of transported toxic gases/vapours. Fire or explosion in
case of transport or ejecon of ammable gases/vapours, oxidising agents or
pyrophoric gases.
Transported process gases can escape out of the exhaust pipe and from leaking areas
of the vacuum system.
Transport of toxic gases/vapours, ammable gases/vapours, oxidising agents or
pyrophoric gases is not permied.
In its standard version, the pump system is not suitable for operaon in EX zones.
The operator is responsible for the assessment of the hazard potenal of the process
media and/or mixtures. For this purpose, the operator must perform a risk or hazard
assessment. The operator must take appropriate measures to make sure that there is
no danger to man and the environment.
Do not use ammable materials near the hot pump area.
WARNING: HARMFUL VAPOUR
Hazards through emission of harmful gases/vapours.
During the start-up and the new installaon of the heater cartridge, smoke and an
unpleasant smell may develop. Therefore, turn on new pumps and pumps aer
successful servicing of the heater cartridges only in well venlated areas. Avoid direct
contact with the smoke or gases that can develop during start-up.
WARNING: LUBRICANT REACTION
Danger as a result of contact with toxic decay/reacon products of lubricants,
equipment or pumped substances during the maintenance of the pump.
There may be deposits in the pump during servicing. The pumping of toxic gases and
vapours is prohibited.
The operator is responsible for the assessment of the hazard potenal of the process
media and/or mixtures. For this purpose, the operator must perform a risk or hazard
assessment. The operator must take appropriate measures to make sure that there is
no danger to people and/or the environment.
For this purpose, we recommend that the pump is ushed for a longer me with inert
gas before opening. Wear appropriate protecve clothing (gloves, goggles,
respiratory protecon, personal protecve equipment).
Avoid body contact with plant oil, process residues and contaminated surfaces.
Perform maintenance in clean, dry and well venlated rooms.
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WARNING: HAZARDOUS WORKING CONDITION
Danger as a result of contact with toxic decay/reacon products of lubricants,
equipment or pumped substances during the maintenance of the pump.
Wear appropriate protecve clothing (gloves, goggles, respiratory protecon,
personal protecve equipment).
Avoid body contact with plant oil, process residues and contaminated surfaces.
Perform maintenance in clean, dry and well venlated rooms.
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3. Descripon
The pumps in the nHT series are high vacuum pumps (< 10-2 mbar). They are always
operated together with the backing pumps.
The pumps are water cooled and ulise the oil diusion principle in their operaon.
They are used in high vacuum technology to evacuate vacuum chambers.
The pumps achieve the highest pumping speeds in pressure ranges from 10-2 to
10-7 mbar.
3.1 Design and funcon
The pumps comprise the following component assemblies:
▪ A water cooled pump housing with inlet and outlet vacuum connecon anges
▪ An interior assembly
▪ An internal vaporisaon chamber (boiler) with heang elements
▪ A water cooled cold cap bae
▪ A backing bae
▪ An electrical terminal box.
Interior assembly
The pumps are ed with a ve-stage precision interior assembly. It consists of four
diusion jet stages and an ejector stage, made of light alloy metal.
Pump body
The pump body is made of standard grade steel. The inlet connecon ange and the
outlet vacuum ange are made of stainless steel. The external cooling coils are made of
copper.
Heat diusion ns
The external coiled heang ns on the cartridge heaters are made of stainless steel and
are immersed for the most part in the pump uid in the vaporisaon chamber.
The secon of the heang n immersed in the pump uid produces intense but surge
free vaporisaon of the pump uid.
The secon of the heang n located above the level of the pump uid applies
addional energy to the pumping vapour.
Thermostat
To protect the heang element, a thermostat sensor is aached to one of the heater
cartridges. When installed, it protrudes above the uid. It must be used to turn o the
pumps heaters as soon as the bimetallic switch temperature reaches the preset trip
point.
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Note:
The sensor has to be installed into the system control by the customer so that it will
safely turn o the power.
Heang cartridges
The heang cartridges can be easily replaced when required. It is not necessary to
remove the pump from the system to replace the cartridges.
Cold cap bae
To prevent vapour from back‑ow into the vacuum chamber, the pump is ed with a
nickel plated copper, water cooled cold cap bae in the area of the inlet port.
Backing bae
A water cooled backing bae located on the fore vacuum side eecvely prevent the
uid being swept into the backing pump.
Figure 1 Overview of nHT diusion pump
1. Outlet connecon ange 2. Backing bae
3. External cooling coils 4. Interior assembly
5. Inlet connecon ange 6. Cold cap bae
7. Pump body 8. Electrical terminal box
9. Heater cover plate
1. Outlet connecon ange 2. Backing bae
3. External cooling coils 4. Interior assembly
5. Inlet connecon ange 6. Cold cap bae
7. Pump body 8. Electrical terminal box
9. Heater cover plate
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3.2 Supplied equipment
All pumps are shipped without pump uid. Standard equipment included with the pump
are:
▪ Inlet seal O-ring for ANSI pumps
▪ Centring ring seal for ISO pumps.
▪ Outlet seal O-ring for ANSI pumps
The inlet and outlet vacuum anges are covered with shipping anges. The inside of the
pump is cleaned and evacuated before shipment.
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4. Technical data
4.1 Dimension drawings
Figure 2 nHT10 Dimensions
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Figure 3 nHT16 Dimensions
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Figure 4 nHT20 Dimensions
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Figure 5 nHT32 Dimensions
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