Utah-94-721002-System-Manual.pdf - 第235页
System Manual lñÑçêÇ= fåëíêìãÉ åíë=m ä~ëã~ = qÉÅÜåçäçÖó== lfmq=póëíÉãë UK= bñíê~Åíáçå= The following mandatory re quirements describe the ext raction systems recommended by OIPT . While these recomm endations may be re g…
lfmq=póëíÉãë lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual
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WARNING
IF LIQUID NITROGEN FACILITIES ARE NOT INSTALLED, OPERATED AND MAINTAINED
CORRECTLY, DANGEROUS SITUATIONS CAN RESULT. THESE INTRODUCE RISKS OF:
A) HAZARDOUS PRESSURE BUILD-UP CAUSED BY THE BOIL-OFF OF LIQUID
NITROGEN, WHICH CAN RESULT IN AN EXPLOSION.
B) PERSONAL INJURY FROM TOUCHING PIPEWORK OR OTHER SYSTEM
COMPONENTS CARRYING LIQUID NITROGEN. THIS RISK CAN REMAIN EVEN
AFTER VENTING THE CHAMBER.
C) ASPHYXIATION CAUSED BY THE BOILED-OFF LIQUID NITROGEN REPLACING
OXYGEN IN THE SYSTEM ENVIRONMENT.
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• Ensure that the Liquid Nitrogen installation is carried out in accordance with
local safety regulations. This includes the following:
(a) No part of the Liquid Nitrogen circuit can become blocked with ice
or other contaminants.
(b) Adequate precautions, e.g. pressure relief valves, are fitted to
prevent hazardous pressure build-up from boil-off of the Liquid
Nitrogen.
(c) All system components carrying Liquid Nitrogen are adequately
insulated, and covered to prevent personnel touching exposed
components.
• Ensure that the installation is inspected by a Specialist to confirm that it is
safe to use. Inspections must be carried out before the system is
commissioned and at regular intervals throughout its life.
• Pipework from the Dewar to the system must be adequately insulated and
connected to the system via a
3
/
8
” Swagelok connector.
Services Specifications
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System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== lfmq=póëíÉãë
UK= bñíê~Åíáçå=
The following mandatory requirements describe the extraction systems
recommended by OIPT. While these recommendations may be regarded as “good
practice”, they are not a complete definition of the safety standards required when
handling toxic, corrosive or otherwise hazardous gases. It is the customer’s
responsibility to ensure that the installation meets all relevant local safety
regulations and OIPT accepts no responsibility in this respect.
For detailed information about the safety aspects of gas handling and pumping
systems, the customer should consult the relevant manufacturer/supplier of the
gases and pumps to be used.
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The installation must provide a rotary pump exhaust extraction system which
matches the rotary pump exhaust and which conforms to local safety standards.
In particular, all fittings and pipework connected to the rotary pump exhaust must
be made from industry standard stainless steel in accordance with local safety
regulations.
Specialised equipment such as scrubbers and furnaces may be needed to dispose of
hazardous gases. The routing of the pump exhaust line must be arranged so that
condensates cannot flow back into the pump.
Note that there is a risk of damage from cross-contamination if rotary pumps share
one exhaust system. This applies whether the pumps are on the same system or on
different systems. Damage caused by any cross-contamination is not covered by the
system warranty.
Care must be taken to route mutually incompatible exhaust gases through separate
exhaust ducts. In particular, oxygen enriched exhaust gases should not be mixed
with exhausts from mineral oil pumps, otherwise, an explosion may occur.
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The gas pod must be connected to the customer's gas extraction system via a 100
mm diameter pipe collar to provide cabinet extraction with a minimum flow rate of
1 m
3
/hour (6-line gas pod) or 3 m
3
/hour (12-line gas pod), i.e. an extraction vacuum
of approximately 500 Pa relative to local atmospheric pressure is required. It is the
customer’s responsibility to ensure that the gas extraction system, including any
necessary gas sensors, meets local safety regulations.
Services Specifications
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lfmq=póëíÉãë lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual
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WARNING
ANY CRYOGENIC PUMP, WHICH PUMPS HAZARDOUS GASES MUST HAVE, A VENT
PIPE FITTED TO ITS RELIEF VALVE TO PREVENT THE RELEASE OF GAS INTO THE CLEAN
ROOM.
THE PUMPS COLLECT THE PROCESS GASES AND THE GASEOUS RESIDUES DURING
OPERATION. THESE GASES ARE RELEASED THROUGH THE RELIEF VALVE DURING
PUMP REGENERATION OR IF ELECTRICAL POWER IS LOST.
If a cryogenic pump is used to pump toxic, corrosive, or flammable gases, a written
action plan is required. This must be prepared in consultation with OIPT and other
competent bodies. Specialised equipment such as scrubbers and furnaces may be
needed to dispose of hazardous gases.
If the pumped gases contain more than 20% oxygen, a vent pipe must be fitted to
the system’s cryo pump outlet connector. The vent pipe must be routed to a safe
place outside of the clean room and conform to local safety standards.
If a cryogenic pump is used to pump gases containing more than 20% oxygen, the
associated roughing pump(s) must be lubricated with a PFPE fluid, e.g. Fomblin or
Krytox.
Services Specifications
Issue 16: April 05 Page 18 of 22 Printed: 6-Jan-06, 8:44