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29 Cards in this Set
- Front
- Back
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How is liquid O2 stored in Liquid O2 systems?
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- stored at -183 C or -297 F in thermos bottle type storage vessels (inner & outer steel shells separated by a vacuum
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What don't pressure readings of an O2 cylinder indicate?
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- the remainder in the cylinder because the liquid O2 doesn't exert gas pressure
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What will indicate the remainder of O2 in a cylinder?
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- weight
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What should pressures in LOX containers never exceed?
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- 250psi
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Who determines the specifications for bulk systems?
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- NFPA (National Fire Protection Association)
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What is the purpose of piping systems?
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- locate zone valves in hospital
- do not turn off unless directed by fire chief |
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What is the most economical gaseous bulk system?
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- liquid oxygen systems
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What does 1 ft3 of liquid O2 equal?
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- 1 ft3 of liquid O2= 860 ft3 of gaseous O2 at ambient temperature
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When are liquid O2 cylinders used?
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- when usage too large for & not large enough for a permanently liquid vessel (come in various sizes)
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What are fixed station (stand tanks) in a liquid O2 system?
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- large & spherical w/ gaseous equivalents up to 130,000 cubic feet (refilled by service tank trucks)
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What are all liquid O2 containers equipped with?
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- 50psi reducing valves
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What is the formula for liquid O2 duration (in minutes)?
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lbs. of liquid O2 x 344/ liters per minute
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What are the safety precautions for bulk O2?
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- must have 24 hour reserve or back-up supply
- procedure for total system failure should be known |
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What are the 2 parts of an oxygen concentrator?
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- membrane
- molecular sieve |
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Describe the membrane of an oxygen concentrator
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- thin membrane (1 micrometer thick)
- O2 & H2O pass through membrane faster than nitrogen - delivers an FIO2 of about 40% |
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Describe the molecular sieve of an oxygen concentrator
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- uses a sieve filled w/ sodium-aluminum silicate
- air is forced through the sieve - the nitrogen is scrubbed from the air - delivers an FIO2 of about 90% at 2 liters per min. - at higher flows the FIO2 decreases |
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What do regulators do?
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- reduce high tank pressure to low working pressure (usually 50psi)
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What does a single stage regulator do?
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- reduces tank pressure to 50psi in 1 step
- has one pressure relief valve (about 200psi) |
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What does a multi-stage regulator do?
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- reduces tank pressure to working pressure in 2 or more steps
- each stage has a pressure relief valve - the more stages/the less fluctuation of working pressure |
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What is a preset regulator?
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- single or multi-stage regulator that is set to have pressure reduced to set working pressure (usually 50psi)
- has no way to adjust working pressure |
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What is an adjustable regulator?
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- single or multi-stage regulator in which working pressure may be set variably
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What do flowmeters do?
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- control & indicate flow
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What is a Thorpe Tube?
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- vertical funnel shape tube w/ float (must be kept vertical to be accurate)
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What are the characteristics of a Compensated Thorpe Tube Flowmeter?
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- needle valve adjustment is distal (after or downstream) to the float
- indicated flow is accurate in the presence of back pressure to check for compensation: label calibrated at 70 F, 50psi |
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What is important to know when operating a Compensated Thorpe Tube Flowmeter?
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- visualize needle valve placement
- turn unit off and plug into pressure - float will rise, then fall, when initially inserted into wall outlet |
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What are the characteristics of an Uncompensated Thorpe Tube Flowmeter?
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- needle is proximal (upstream or before) the float
- flow meter reading will be LOWER than what is delivered to the patient IF BACK PRESSURE IS PRESENT |
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What are the characteristics of a Kinetic Flowmeter?
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- has plunger instead of float
- all other areas of Thorpe Tube apply |
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What are the characteristics of a Bourdon Gauge?
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- measures pressure but reads flow
- flow delivered to patient IS LESS than flow shown on the gauge, IF BACK PRESSURE IS PRESENT |
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What is the benefit of a Bourdon Gauge?
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- works in any position
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