Search results
Results from the WOW.Com Content Network
The standard liter per minute (SLM or SLPM) is a unit of (molar or) mass flow rate of a gas at standard conditions for temperature and pressure (STP), which is most commonly practiced in the United States, whereas European practice revolves around the normal litre per minute (NLPM). [1]
Large oxygen cylinders hold a volume of 6,500 litres (230 cu ft) and can last about two days at a flow rate of 2 litres per minute (LPM). A small portable M6 (B) cylinder holds 164 or 170 litres (5.8 or 6.0 cu ft) and weighs about 1.3 to 1.6 kilograms (2.9 to 3.5 lb). [62]
Climbers sometimes carried only two cylinders each. Four cylinders contained a total of 960 litres of oxygen, which would last for eight hours at the standard rate of 2 litres per minute or seven hours at 2.2 L/min. [32] The attempt on Everest by George Mallory and Andrew Irvine in 1924 was the first summit attempt using oxygen on Everest. [31]
With continuous flow units, oxygen delivery is measured in LPM (liters per minute). Providing continuous flow requires a larger molecular sieve and pump/motor assembly, and additional electronics. This increases the device’s size and weight (approximately 18–20 lbs). [13]
V̇O 2 max is expressed either as an absolute rate in (for example) litres of oxygen per minute (L/min) or as a relative rate in (for example) millilitres of oxygen per kilogram of the body mass per minute (e.g., mL/(kg·min)). The latter expression is often used to compare the performance of endurance sports athletes.
Older units cycled for a period of about 20 seconds and supplied up to 5 litres per minute of 90+% oxygen. Since about 1999, units capable of supplying up to 10 L/min have been available. Classic oxygen concentrators use two-bed molecular sieves; newer concentrators use multi-bed molecular sieves.
The oxygen delivered while the patient exhales or pauses is not used. Say for example the machine delivers 2 liters per minute, the respiratory minute volume is 10 liters and the patient inhales 50% of the time, then the total amount inhaled will be 1 liter from the machine (50% of the output) and 9 liters ambient air.
0.1 × ( 12 ÷ 8 ) = 0.15 grain per dscf when corrected to a gas having a specified reference CO 2 content of 12 volume %. Notes: Although ppmv and grains per dscf have been used in the above examples, concentrations such as ppbv (i.e., parts per billion by volume), volume percent, grams per dscm and many others may also be used.