Physics and Gases Flashcards
(69 cards)
3 components of pressure regularators
tightly wound spring attached to diaphragam which is connected to a valve controlling high pressure gas input.
PSI of central oxygen tank
55 psi, primary source for anesthesia machine
Pipeline pressure
- psi. Pipeline gauge located on pipeline side of check valve to avoid checking pressure within machine. Has both pressure regulators for pipeline and cylinder
secondary gas source for anesthesia maachine
e-cylinders. Pressurized to 2200 psi and have a regulator bc they need lower pressures. Separate regulators for each cyclinder
Regulator in O2 reserve cylinder reduces pressure from ___ to ___
2200 to 45 psi, second stage will reduce to 14
Regulator in nitrous reserve cylinder reduces pressure from ___ to ___
745 to 45 psi, second stage will reduce to 26
what happens if 2 cylinders are open at same time what will gauge read
cylinder w higher pressure
Oxygen e-cylinder (color, pressure at room temp, physical state)
green, 2000, gasN
Nitrous oxide (color, pressure at room temp, physical state)
blue, 745, liquid/vapor
Carbon dioxide (color, pressure at room temp, physical state)
Grey, 840, liquid/vapor
Air (color, pressure at room temp, physical state)
yellow, 1800, gas
Entonox (color, pressure at room temp, physical state)
blue, 2000, gas
heliox (color, pressure at room temp, physical state)
Brown, 2000, gas
Full e-cylinder of O2
660 L
Full e-cylinder nitrous
1600L at 750 psi. Volume cannot be determined by pressure guage. Pressure will remain at 750 until it has all been vaporized which means 20% of intial volume remains when there’s a drop in pressure
laminar flow, relationship to pressure gradient
directly proportional to pressure gradient (flow related to pressure), R is a constant, F=deltaP/R
turbulent flow, relation to pressure
nonlinear relationship between flow and pressure. flow rate is proportional to square root of pressure gradient
reynolds number
Re = densityvelocitydiameter/viscosity, point at which a fluid transitions from laminar to tubrelnt
Poueuille equation
Q = delta Ppir^4/ 8viscosity*length
describes relationship between variables that affect flow rate and laminar fluids
Bernoulli’s equation
sum of all energies per unit volume remains constant at all points along line of fluid when laminar
P1 + 1/2(densityvelocity^2) = P2 + 1/2(densityvelocity^2)
Venturi effect
when a fluid passes through a tube with varying diameters, lateral pressure exerted by fluid drops because of increase in velocity when there’s constriction
hyperechoic
strong reflection, white dot
bones, tendons, ligaments, diaphragm, nerves, liver angiomas, tumor, blood vessels, fibrosis, liver steatosis
weaker - solid organs, thick fluid, gray
anechoic (no reflection)
cysts, ascites, fluid
ultrasound transducer frequency and wavelength
increase frequency, increases image resolution, decreases ability of waves to penetrate
12Mhz waves - good resolution, not deep
3Mhz goes deep, but bad resolution
