Gas Supply and the Anaesthetic Machine

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Critical Temperature ◽  
Anaesthetic Machine ◽  
Liquid Oxygen ◽  
Liquid Form ◽  
Relief Valve ◽  
Gaseous Oxygen ◽  
Hospital Building ◽  
Pass Through ◽  
Delivery Pipe ◽  
Gas Supply

In Europe and other advanced medical communities, medical gases are generally supplied by pipeline, with cylinders available as back up. Large hospitals usually have oxygen supplied and stored in liquid form, since one volume of it provides 840 volumes of gaseous oxygen at 15◦C. It is stored in a secure Vacuum Insulated Evaporator (VIE) on the hospital site. The arrangement is shown in Figure 22.1. The VIE consists of an insulated container, the inner layer of which is made of stainless steel, the outer of which is made of carbon steel. The liquid oxygen is stored in the inner container at about−160◦C (lower than the critical temperature of−118◦C) at a pressure of between 700 and 1200 kPa. There is a vapour withdrawal line at the top of the VIE, from which oxygen vapour can go via a restrictor to a superheater, where the gas is heated towards ambient temperature. Where demand exceeds supply from this route, there is also a liquid withdrawal line from the bottom of the VIE, from which liquid oxygen can be withdrawn; the liquid can be made to join the vapour line downstream of the restrictor and pass either through the superheater or back to the top of the VIE. The liquid can also be made to pass through an evaporator before joining the vapour line. After passing through the superheater, the oxygen vapour is passed through a series of pressure regulators to drop the pressure down to the distribution pipeline pressure of 410 kPa. It should be remembered that no insulation is perfect and there is a pressure relief valve on top of the VIE in case lack of demand and gradual temperature rise results in a pressure build up in the container. There is a filling port and there is usually considerable wastage in filling the VIE; the delivery hose needs to be cooled to below the critical temperature, using the tanker liquid oxygen itself to cool the delivery pipe. The whole VIE device is mounted on a hinged weighing scale and is situated outside the hospital building, protected by a caged enclosure, which also houses two banks of reserve cylinders.

Low energy electron ranges in liquids: determination by nonhomogeneous kinetics

1977 ◽  
Vol 55 (11) ◽  
pp. 2050-2062 ◽  
Author(s):  
J.-P. Dodelet
Keyword(s):  
Critical Temperature ◽  
Melting Point ◽  
Distribution Functions ◽  
Liquid Density ◽  
Range Distribution ◽  
Total Ionization ◽  
Free Ion ◽  
Drastic Increase ◽  
Pass Through ◽  
Ion Yields

Free ion yields have been measured in four hydrocarbon liquids: n-pentane, cyclopentane, neopentane, and neohexane. Each liquid has been studied from room temperature or below up to the critical temperature. Theoretical curves have been calculated using the relation between the free ion yields and the external field strength derived by Terlecki and Fiutak on the basis of an equation by Onsager. Two popular electron range distribution functions, Gaussian and exponential, have been shown not to be an adequate representation of the reality as far as the model used for the calculations is concerned. In order to fit experimental points, both range distribution functions would require a drastic increase in the total ionization yield, Gtot, with temperature increase. This would mean an unrealistic decrease of the ionization potential of the molecule from the melting point up to the critical temperature.It is possible to keep Gtot quite constant and within the range of values obtained by other techniques by extending the Gaussian range distribution function with a (range)−3 probability tail. The most probable range can be normalized for the liquid density. This parameter has been used to obtain information about the behaviour of epithermal electrons in the four alkane liquids from the melting point up to the critical temperature.(1) Normalized penetration ranges of epithermal electrons are dependent on the structure of the molecule in the entire liquid range but differences are smaller at critical than at low temperatures.(2) Normalized penetration ranges of epithermal electrons pass through a maximum in the liquid phase for neopentane, neohexane, and cyclopentane. No maximum is observed for n-pentane.(3) There is no drastic change in the behaviour of epithermal electrons in these alkanes at the critical temperature.

scholarly journals Efficiency of the process of cryogenic air separation into the components

2009 ◽  
Vol 63 (5) ◽  
pp. 397-405 ◽  
Author(s):  
Milance Mitovski ◽  
Aleksandra Mitovski
Keyword(s):  
Energy Consumption ◽  
Power Consumption ◽  
Liquid Nitrogen ◽  
Separation Process ◽  
Air Separation ◽  
Production Costs ◽  
Liquid Oxygen ◽  
Gaseous Nitrogen ◽  
Gaseous Oxygen ◽  
Energy And Exergy

The separation process of atmospheric air into its components by means of cryogenic low-pressure procedure, which takes place in the Oxygen plant in the Copper Mining and Smelting Complex, yields various products of different quantities and purities. Proper assessment of the energy consumption, hence assignments production cost of individual products may present considerable problem. For that goal, the least invested technical operation was adopted as criteria, and was restrained for all costs of production and distribution of specific energy. Case study was carried out in the Oxygen factory by monitoring producing parameters for the process in the 2007 year. Based on the monitoring of production parameters and their costs for 20 months in the period 2004-2005, correlation equations for power consumption in the total monthly amount and per mass of produced gaseous oxygen were created. The energy and exergy efficiency of the air separation process into the components are expressed as the ratio of input and useful energy and exergy of the process. On the basis of the adopted criteria, the assignments of energy consumption and production costs for cryogenic air separation process into the components are as follows: 82.59% for gaseous oxygen, 14.04% for liquid oxygen, 1.39% for gaseous nitrogen and 1.98% for liquefied nitrogen. The air separation efficiency is achieved in the amount of energy 0.0872-0.1179 and exergy 0.0537-0.1247. Power consumption per mass of the products in 2007 year is 1325.059 kWh/t of liquid oxygen, 828.765 kWh/t of liquid nitrogen, 429.812 kWh/t of gaseous oxygen and 309.424 kWh/t of nitrogen gas. Production costs of the technical gases at the dawn of the factory are: 6730.69 RSD/t of liquid oxygen, 4209.74 RSD/t of liquid nitrogen, 2183.25 RSD/t of gaseous oxygen and 1571.73 RSD/t of gaseous nitrogen.

scholarly journals Spectrum of the flame of ethylene

1934 ◽  
Vol 147 (862) ◽  
pp. 513-521 ◽  
Keyword(s):  
Ultra Violet ◽  
Detailed Examination ◽  
Outer Tube ◽  
The Other ◽  
Bunsen Flame ◽  
Ethylene Flame ◽  
Carbon Compounds ◽  
Pass Through ◽  
Gas Supply

In the course of a detailed examination of the spectra of the flames of carbon compounds, which was undertaken at the suggestion of Professor A. Fowler, it has been found that the flame of ethylene shows, in addition to the familiar bands of C 2 , CH and HO, a system of bands which has not previously been adequately described. These bands occur feebly in the ordinary Bunsen flame, as noted by Rassweiler and Withrow, and with greater intensity in the flame of ether, as shown in a photograph by Emeléus. Other flames which exhibit these bands have also been found in the course of the present investigation, but as the bands appear to have their greatest intensity in ethylene, they may conveniently be called the “ethylene flame bands” for the purposes of the present paper. The bands are degraded to the red, and have been observed to extend from λ 4100 to λ 2500. For the production of the bands under the most favourable conditions it was necessary to use a Smithells’ flame separator to divide the inner and outer cones. The separator employed, fig. 1, considered to two concentric tubes, F and G, the inner tube, F, being mounted on the outer nozzle, D, of a two-way blow-pipe. The inner tube was made of Pyrex, 15cm in length and 1·2 cm in diameter, while the outer one—12 cm long and 1·5 cm in diameter—was made of quartz so as to permit observations in the ultra-violet. The inlet A was connected to a cylinder of ethylene gas (rated 100% pure), the arrangement being such that the gas could then pass through the outer nozzle, D. Through the inner nozzle, E, could be passed air blown through the other inlet, B, by an electric blower. In the absence of air, the gas burnt with a smoky flame on the outer tube, G. When air was blown through, the flame became non-luminous and, with suitable adjustment of air and gas supply by the handle, C, the inner cone was clearly developed. Then, on sliding the inner tube of the separator about 4 cm below the top of the outer tube, the cones were completely separated, the inner cone burning steadily on the inner tube. Under these conditions the inner cone was about 2 cm high, and was of greenish colour.

scholarly journals On-Board Oxygen Generation Using High Performance Molecular Sieve

2017 ◽  
Vol 2 (4) ◽  
pp. 380 ◽  
Author(s):  
Ajaz A. Bhat ◽  
H. Mang ◽  
Rajkumar S. ◽  
T. M. Kotresh ◽  
U. K. Singh
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
High Performance ◽  
Environmental Control ◽  
Solenoid Valve ◽  
Limiting Factors ◽  
Liquid Oxygen ◽  
Gaseous Oxygen ◽  
System Pressure ◽  
Pipe Line

<p class="p1">The majority of high performance combat aircrafts presently being operated by Indian air Force are fitted with conventional oxygen systems in which a replenishable store of oxygen is carried, most often as liquid oxygen and the flow of gas to each crew member is controlled by an individual pressure demand regulator in which the oxygen is diluted with cabin air to provide breathing gas.Moreover, in-flight refueling capability of present generation fighter aircraft has made it possible to fly for long durations (6 to 8 hours). In such case, the oxygen source becomes one of the limiting factors. In order to meet this requirement, a large supply of Gaseous Oxygen (GASOX) or Liquid Oxygen (LOX) have proven to be a costly affair and the Onboard Oxygen Generating System (OBOGS) has become a very convenient and attractive proposal. The OBOGS employs molecular sieves to adsorb nitrogen from engine bleed air using pressure swing adsorption (PSA) technique, wherein two molecular sieve beds are continuously cycled between steps of pressurization (adsorption) and depressurization (desorption) to generate oxygen enriched breathing gas for aircrew. This paper describes the design of OBOGS using high performance Lithium based Low Silica X-type (Li-LSX) molecular sieves and its performance characteristics. It consists of two Zeolite beds filled with Li-LSX material which adsorbs nitrogen fromengine bleed air tapped from Environmental Control System pipe line. The two beds are cycled by a 5/2 way solenoid valve. The input air is supplied to the solenoid valve through a coalescent filter to reduce moisture from it and a pressure regulator is fitted at the upstream of solenoid valve to regulate the system pressure. The experimental setup for evaluation of OBOGS is also discussed. The OBOGS, presented in this paper, meets all the performance requirements as specified in MIL-C-85521 (AS).<span class="Apple-converted-space"> </span></p>

Pharmacoeconomic evaluation of the costs incurred by the ASP Messina for home therapy with liquid oxygen

2010 ◽  
Vol 11 (1) ◽  
pp. 43-46
Author(s):  
Salvatore Coppolino
Keyword(s):  
Oxygen Therapy ◽  
Pharmacoeconomic Evaluation ◽  
Point Of View ◽  
Liquid Oxygen ◽  
Chronic Obstructive ◽  
Industrialized Countries ◽  
Gaseous Oxygen ◽  
Obstructive Pulmonary Disease ◽  
Doctor Visits ◽  
The Cost

Chronic obstructive pulmonary disease (COPD) is a very frequent disease in all industrialized countries. The cost for the community includes cost for hospitalisations, doctor visits, home care, rehabilitation, loss of working days, etc. From a therapeutical point of view, an effective progression of therapy and patients survival can be obtained only by stopping smoking and by following a long term oxygen therapy. The aim of this retrospective study is to evaluate costs of liquid oxygen therapy performed at home. Obtained results are very encouraging because a part from being cheap they also provide a better evaluation of the prescribed therapy which can also be extended to gaseous oxygen.

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