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98 Cards in this Set
- Front
- Back
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3 gases on every machine
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1. O2
2. N2O 3. Air |
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What is Nitrogen used for
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Ortho cases: to power the drills and power tools
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2 common cylinders
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1. E cylinders
2. H cylinders |
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6 components of Medical gas cylinders
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1. Body
2. Valve 3. Handle or Handwheel 4. Pressure 5. Conical Depression 6. Noninterchangeable Safety System (prongs) |
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What metal are hospital tanks made of
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steal with alloys
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What metal are home tanks made of
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Aluminum
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Color of Oxygen
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green
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Color of Air
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yellow
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Color of Nitrous Oxide
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Blue
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7 Labels on Cylinders
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1. DOT specification #
2. Cereal # 3. Purchaser/user/manufacturer 4. Manufactured date and original test date 5. Manufactured ID symbol 6. Retest date & whether it's a 10yr inspections 7. Owner ID |
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DOT Specification # indicates?
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type of material in manufacturing of cylinder
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Packing Valve
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- attached to neck of cylinder
- it's how each cylinder is filled & discharged - made of bronze or brass & removed only during testing or maintenance - each valve contains a stem - stem sealed by Teflon which prevents leaking around the thread - capable of withstanding high pressure - capable of withstanding high pressure - 2-3 turns to open fully |
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Port on Packing valve
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where gas exits
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Stem on Packing valve
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closes the valve
- open valve: the ___ moves up allowing gas to flow to port |
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most common valve
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Packing valve
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Diaphragm Valve
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- stem separated from seat and flex diaphragm seals the opening to internal parts
- turing stem raises/lowers diaphragm |
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Advantage of Diaphragm Valve
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1. opens fully with 1/2 to 3/4 turn
2. seat doesn't leak/turn 3. no stem leakage occurs b/c diaphragm - prefer this valve when pressures are low and when no leaks allowed (flammable gas) |
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the tool to open or close cylinder
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Handle
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Purpose of pressure relief valve
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vent tank contents to atmosphere if pressure of gas increases to dangerous levels
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3 pressure relief devices
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1. Rupture disc
2. Fusible plug 3. Pressure relief valve |
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Rupture Disc
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- Nonreclosing device with disc held against an orifice
- disc ruptures when pressure is too high. this allows cylinder contents to escape - once disc ruptures the tank is completely empty - protects against overfilling, excess pressure from increased temp |
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Fusible Plug
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AKA: WOODS METAL
- thermally operated nonreclosing pressure relief device - melts at high temp of 212 degrees Ferenheit |
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Most common pressure relief device
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Woods metal
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Pressure relief Vavle
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spring loaded device
- only Reclosing device - prevents discharge of contents after normal pressure is resolved |
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Conical depression
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receives retaining screw of yoke
- holds tank in place |
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Pin Index safety system
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helps prevent wrong tank or gas from being used
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Problem with Pin index system
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if multiple washers are used or pins are damaged it is possible to put the wrong gas on the machine
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Position of pins for N2O
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3 & 5
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Position of pins for O2
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2 & 5
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3 high pressure systems
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1. hanger yoke
2. cylinder pressure indicator 3. pressure reducing device (regulator) |
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What is the purpose of the high pressure system
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receives high pressure and decreases the pressure and makes it a more constant pressure suitable for use on anesthesia machine
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3 Function of Hanger Yoke
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1. Orients cylinder
2. gas tight seal 3. unidirectional flow |
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7 components of Hanger Yoke
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1. Body: principle framework & support structure
2. Retaining Screw: tightens cylinder in yoke 3. Gas Inlet: where gas enters machine 4. Index pin: prevent attachment of incorrect cylinder 5. Washer: help w/ seal btwn cylinder and yoke 6. Filter: removes dirt from cylinder 7. Check valve assembly: ensures unidirectional flow of gas thru the yoke |
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Check valve assembly
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- allows gas from cylinder to enter machine and prevents gas from exiting machine
- will also prevent transfer of one gas from cylinder to another w/ a lower pressure in a double yoke system on anesth. machine |
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Bordon Gauge
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measures High pressure from cylinder
- if both cylinders are open the gauge indicates the higher pressure - lower gauge on machine |
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Pressure reducing device (regulator)
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- maintains constant flow w/ changing supply of pressure
- reduces high and variable pressures found in cylinder to lower and more constant pressure suitable for anesth. machine |
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Cylinder pressure for machine
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40-48 PSI
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Pipeline pressure for machine
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50-55 PSI
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most common contaminant of medical gas lines
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Water
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what do the manifolds on H cylinders do?
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contains vavles that lower cylinder press (2000psi) to line pressure of 50-55psi and will switch tanks automatically when one group of cylinders is empty
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Critical temp
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the temp at which a liquid becomes a gas
- this is done by keeping O2 in an insulated vessel at temps well below critical temp |
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How is O2 kept cold
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by latent heat of vaporization and gas O2 is removed and temp decreased which is how it's kept so cold
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temp O2 is stored at
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160 degrees Celsius to keep it a liquid till it's used
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Full tank of O2 = ? PSI and ? Liters in an E cylinder
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2000 PSI
660 Liter |
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Full tank of N2O = ? PSI and ? Liters in E cylinder
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745 PSI
1590 Liters |
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Full tank of Air = ? PSI and ? Liters in E cylinders
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1900 PSI
625 Liters |
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Critical temp of O2
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118 degrees Celsius
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math:
Capacity (L)/ Serv pressure (PSI) = |
remaining contents (L)/Gauage pressure (PSI)
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Full O2 tank = ? PSI and ? Liters in an H cylinder
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2000 PSI
6900 L |
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critical temp of N2O
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36.5 degrees Celcius
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what pressure is N2O stored at ?
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51atm or 745 PSI
- stored as a liquid |
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N2O tank
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- volume remaining in tank isn't proportional to cylinder pressure
- if liquid N2O is kept at constant temp (usually 20 degrees Celc) it will vaporize at the same rate in which it's consumed and will maintain constant pressure (745psi) until all the liquid is gone - by this time the tank pressure will decrease and have a psi or 350 and all liquid is gone and only gas remains = 125Liter N2O left in tank - can't determine amt of N2O left in the tank by reading the gauge of N2O |
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When to change the N2O tank
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when its pressure is <745 PSI
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Caution with N2O
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- rapidly removing N2O >4L/min will cause frost to form or freeze valve d/t loss of latent heat of vaporization from liquid N2O
- NEVER use greater than 4L/min flow of N2O |
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Helium
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used with at least 20% O2
- a 80:20% or 70:30% mix with O2 |
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3 uses of Helium
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1. Assist flow of O2 into alveoli of pt with severe resp. obstruction
2. to prevent atelectasis 3. for gas transfer lung fxn test |
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Transfilling
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rapid compression of a gas (from H to E tank) may cause cylinder temp to increase and heat can cause combustion
- safety device = Woods Metal would be activated |
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Adiabatic heat of compression =
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generate heat and cause ignition
- all gases cool during adiabatic expansion |
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4 Steps in testing cylinders
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1. inspect and tested at least every 5yrs or 10 w/ special permit
2. must pass an internal/external visual check 3. leak check 4. retention of structural strength: test at minimum of 1.66 times the service pressure ex (1.66 x 2000psi) |
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Service pressure
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the max pressure in which a cyliner may b filled at 70 degrees Ferenheit
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DOT responsibility in Cylinders
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- published requirements for the manufacturing, marketing, labeling, filling, qualification, transportation, storage, maintenance, and disposition of medical gas cylinders and containers
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FDA responsibility with Cylinders
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enforces the purity of medical gas
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OSHA responsibility with Cylinders
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regulates matters affecting the safety and health of employees in all industries
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NFPA responsibility with cylinders
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published standards
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11 hazards to avoid
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1. incorrect cylinder
2. incorrect contents 3. incorrect valve 4. incorrect color 5. incorrect labeling 6. inoperative valve 7. damaged valve 8. fires/explosions 9. contamination of cylinders: medical O2 must be 99% pure 10. overfilling 11. rapid escape of contents/rocketing of cylinder |
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Advantages of liquid O2
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1. compact
2. light weight 3. requires low pressures 4. simple to use |
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How liquid O2 containers work
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each has a pressure relief valve
- when not in use the pressure in containers controlled by venting the excess gas into atmosph = limited time O2 can be stored in these tanks - amt of gas is measured by weight - usually made of alluminum |
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Rules for safe use of Liquid O2
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1. a considerable time must be allowed for the liquid O2 to dissipate if spilled
2. contact btwn skin and liquid must be avoided 3. liquid O2 equipment must be kept clean of organic or combustable materials 4. cryogenic transfilling devices must be kept free of moisture to prevent frost fomation on valves or cufflink and freezing open or closed 5. no extreme heat or cold 6. handled to avoid physical damage 7. markings/labels must be legible 8. no tampering with pressure relief devices |
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Storage of liquid O2
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1. keep in open, cool, well-ventilated area
2. store away from any heat source 3. protected from corrosive atmosphere 4. stored in an upright position |
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3 things about medical gas pipeline
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1. central supply
2. piping which extends to location where gas may be required 3. terminal units at each point of use |
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Pressure lowering regulator
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in main supply line up-stream from pressure relief valve
- will lower pressure to 50-55psi |
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Nitrous Oxide (N2O)
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1. use manifolded cylinders to supply to the pipeline (H cylinders)
2. regulator may become so cold that it freezes 3. stored as liquid at low pressure in insulated vessels 4. need warning signs 5. leaks cause hypoxic mix |
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Medical Air
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1. No detectable liquid hydrocarbons
2. less than 25 ppm gaseous hydrocarbons 3. less than 5mg/m3 of particulates of 1 micron size or greater at normal atm. pressure 4. dew point at 50 psi of less than 39 degrees F - for breathing |
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Air defined by NFPA
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air, regardless of its source, that has no detectable liquid hydrocarbons
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Supply system of medical air
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1. manifolded cylinders
2. proportioning device: mixes gas w/ Nitrogen cylinders 3. motor-driven compressors -majority of piped-air system need 2 or more compressors which operate alternatively or together depending on the demand |
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Pros and Cons for compressor Air
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1. Con: Compressor air is usually less clean and dryer than cylinder air
1. Pro: it is less expensive than cylinder air |
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Air receiver must have:
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1. pressure relief valve
2. automatic drain 3. site lot to visualize drains 4. pressure gauge |
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3 components of Piped distribution system
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1. Main lines
2. Risers 3. Branch lines |
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Main lines
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pipes connecting the source to risers or branch lines or both
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Risers
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vertical pipes connecting the main line with branch lines on various levels of the facility
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Branch lines
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sections of piping system that service a room or group of rooms on the same level of the facility
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3 things that need to be on the pipe every 20 feet
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1. name
2. pressure of gas 3. directional flow |
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Safety devices for pipelines
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1. pressure relief valve: open up if pressure > 50% normal level
2. shut off valve: isolate areas of pipeline for emergency shut off 3. low pressure alarm system: alerts when pressure increases or decreases 20% from normal (may indicate cylinder change) |
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role of shut off
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1. allows sections to be isolated for maintenance or repairs w/o entire system being shut off
2. for emergency |
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2 types of shut off valves
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1. manual
2. service |
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Manual shut off valve
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visible at all times and accessable
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Pipelines in OR appearances
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1. hose drops
2. gas columns 3. articulating arcs - color coded - wither DISS (diameter index safety system) or quick connectors |
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Quick connectors
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easy to use but leak
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Diameter Index safety system
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- non-interchangable connection for medical gas lines at pressures of 0 psi or less
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each connection of DISS consists of
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1. body
2. nipple 3. nut combo |
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DISS fitting
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- miss-connection prevented by different threading and sizing
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3 safety features in pipeline system
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1. filter
2. check valve 3. pressure gauge |
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Check valve
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ensures unidirctional flow and prevents O2 from escaping anesth. machine and going back into hospital wall
- Called Floating Valve |
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Problems with pipeline system
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1. inadequate pressure
2. excessive pressure 3. Alarm problems 4. Cross-connections of gas 5. contamination of gas 6. fires |
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4 ways there could be an inadequate pressure for pipeline system
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1. environmental forces (cold, earthquake)
2. depletion or damage to central supply 3. human error 4. equipment failure |
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most frequent reported problem with pipeline system
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Loss of Pressure
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Most common gas contamination in pipeline system
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N2O mix-up
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Disaster plan
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1. conservation of existing supplies and acquisition of additional supplies
2. determine needs and supplies on hand 3. be aware of your role 4. know locations of shut off valves 5. immediate response to problem 6. possible postposing of surgery |
