DE1279472B - Evaporation system for liquid oxygen to supply oxygen to breathing apparatus - Google Patents

Description

Evaporation system for liquid oxygen for oxygen supply of respiratory protective devices The invention relates to an evaporation system for liquid Oxygen for supplying oxygen to breathing apparatus, especially high altitude breathing apparatus, with an evaporator to which the liquid oxygen is fed through a feed line is, a filling line, a removal line with a device for draining of pressurized gas, and two or more containers for the liquid oxygen, each of which has an upper and lower outlet for the Has gaseous or liquid oxygen. Such plants are preferred Used on airplanes to include crew members and occasionally passengers to supply gaseous oxygen from the container or containers with liquid oxygen. To do this, a certain amount of liquid oxygen is fed into the lower outlet of the container taken and passed through the feed line into the evaporator, from where the gaseous oxygen as needed with oxygen supply devices to the respirators is fed. The container also has an upper outlet that communicates with the Withdrawal line is connected, which has a relief valve that makes it possible To let off parts of the gas contained in the container, if there is a too in the container large overpressure has arisen. This line can be connected to the filling line so that part of the discharged gas can be made usable. This Part is called the savings cycle. The filling line connects the lower outlet of the Container with a filling and venting valve, which is designed as a combination valve and is arranged to have a reservoir for liquid oxygen to be connected filling valve of the container with liquid oxygen under medium Pressure can be refilled while the top of the tank has a connection can be vented between the extraction line and the vent valve.

The system also includes a pressure-generating circuit to the Pressurize liquid oxygen in the container before entering the feed line is drained. The pressure is required to move the liquid oxygen through the Press the vaporizer and the oxygen supply device with the desired Apply pressure. The pressure-generating circuit includes a heat exchanger, the with the upper and lower outlet of the container through the extraction and the feed line, respectively connected is. The under the influence of gravity from the container into the heat exchanger flowing liquid oxygen evaporates and flows back into the container, where he puts its contents under pressure.

Another one required for evaporation systems in aircraft Part is a stabilization circuit, which has the task of essentially one ensure the same temperature of all liquid oxygen in the container, and this is achieved by removing some of the liquid oxygen from the fill line is branched off, evaporates and bubbles through the liquid oxygen in the container, the contents of which are thoroughly mixed and heated.

Systems with multiple tanks can be particularly useful in war aircraft may be required where it is desired that damage to a container not cuts off all oxygen supply. Therefore a number of containers are attached arranged as far away from each other as possible in different parts of the aircraft, which should all be emptied evenly, so that at no time the entire available oxygen is concentrated in a container.

It is known that a simple multiple arrangement is not satisfactory because mostly a container tends to develop a slightly higher pressure than the other. This container is then completely emptied, whereas the other one or the other stay filled. Attempts have been made to remedy this by making the liquid Oxygen-containing parts of the container are connected by a pipe.

However, this must be very short and well insulated in order to evaporate to avoid, and consequently prevents the desired spatial distance of the Containers from each other.

If sensitive valves that open when pressure are used, then has turned out that these do not work reliably enough. Another solution exists in the doubling of the entire circuits with valves for connecting the gas supply lines at the outlet of the evaporator.

The invention is therefore based on the object of an evaporation system for liquid oxygen from several containers that are to be stored far away from each other to provide oxygen supply to breathing apparatus that is more simply constructed is and still works reliably and although not exactly the same, so at least essentially the same withdrawal amount from all containers guaranteed.

The solution is that the lower outlet of the first container both with the filling line and with the feed line, viewed in the direction of flow, connected in front of a first valve that opens at a certain fluid pressure is that the lower outlet of each of the following containers has both a also valve with the feed line that opens at a certain fluid pressure, seen in the direction of flow, behind the first valve and with the upper outlet of the previous container and that the upper outlet of the last container in the Row is connected to the sampling line.

In the system according to the invention, the containers are between the Filling line and the removal line connected in series, and the lower outlet of the first container is with both the filling line and the feed line before connected to the first valve, whereas the lower outlets of the other containers respectively with the feed line, seen in the direction of flow, behind the first valve below Interposition of a further valve are connected.

In addition to increasing security in war aircraft, the system can according to the invention can also be used when an additional storage container for oxygen should be added to an existing system in order to create a to cover increased consumption or to increase the efficiency of the system. In such cases, the invention combines the advantage of security with that of ease, with which additional container is inserted into the system without major difficulty can be.

Further features of the invention are the subject of the subclaims.

Exemplary embodiments are described with reference to the drawing. It shows Fig. 1 shows a system with two containers and FIG. 2 shows a system schematically with four containers.

According to FIG. 1, the system includes two containers 1 and 2, of which each has an upper and lower outlet. The main constituents parts of the Circuit are an evaporator3 in which the liquid oxygen evaporates and from from which it is fed to a consumer line 7, a feed line 4, which leads from the lower outlets of both containers to the evaporator 3, a filling line 5, by means of which liquid oxygen is fed into the container, and a withdrawal line6, by the gaseous oxygen withdrawn from the upper outlets of the containers either drained or fed to the consumer line 7. At the consumer line 7 a valve (not shown) or a pressure reducer is connected to the To control extraction of oxygen from the evaporator 3.

The system also includes a filling and venting valve 10, its End 11 is designed for connecting a filling nozzle, not shown, through which liquid oxygen under moderate pressure to refill the system is fed. The filling and venting valve is connected to the line 12 and the extraction line 6, a line 14 and a vent pipe 13 connected. When the valve is through the connection of the filling nozzle is open, channels connect the inlet of the filling nozzle with the line 12 and the extraction line 6 with the ventilation pipe 13. Remove when the filling coupling, the valve is automatically switched back to the closed position, in which the vent pipe 13 and the inlet into the line 12 are closed and a channel connects the extraction line 6 to the line 14.

Between the line 12 and the filling line 5 is a stabilizing circuit switched. This consists of a non-insulated vessel 15 with a lower one Connection to line 12 and an upper connection to a downpipe 16, the is connected to the filling line 5 via a switching valve 17, as well as a heat exchanger 18 with an upper connection to the line 12 and a lower connection to the Switching valve 17. This valve has a first switching position in which the downpipe 16 is connected to the filling line 5, and a second switching position in which a path between the lower junction of the heat exchanger 18 and the fill line 5 is released. The valve is designed so that it is automatically from the first switches to the second switching position when the pressure in the downpipe 16 is equal to the Pressure in a sensor line 19 leading to the extraction line 6 is.

To the pressure generating circuit includes a heat exchanger 20, whose lower connection to feed line 4 and its upper connection to the line 14 with the interposition of a pressure control valve 21 leads. The pressure control valve 21 consists of a combination of two valves, the first of which is on pressure appealing shut-off valve is, which the way from the upper outlet of the heat exchanger 20 to line 14 interrupts when the pressure at the outlet of the heat exchanger 20 the has reached the desired working pressure, while the second one that opens when pressure is applied Valve is which a connection between the line 14 and a gas supply line 22 produces when the pressure in the line 14 has reached a certain level. At pressures below working pressure, the lower outlet is one or both Container via valve 26 or valves 26 and 29, via heat exchanger 20, the part of the pressure control valve that closes when pressure is applied 21, the Line 14 and the filling and venting valve 10 are connected to the extraction line 6. The part of the pressure control valve 21 that opens when the pressure is applied, together with the gas supply line 22 represents a savings cycle in which excess gas from the container is utilized will. The valve also contains a device for pressure relief, by means of which a dangerous overpressure in the extraction line 6 or the feed line 4 a drain pipe 30 can be drained.

The filling line S leads to the lower end of a downpipe 25, the upper end is connected to the lower outlet of the container 1. The downpipe is with its lower end also connected to the inlet end of the feed line 4. That Valve 26 is in the feed line, viewed in the direction of flow, immediately behind their connection to the downpipe 25 is arranged.

The lower outlet of the container 2 is with both the upper outlet of the container 1 via a line 27 and with the feed line 4 via a downpipe 28 tied together. In the downpipe below its connection with the line 27 is the Valve 29 arranged. In addition, the upper outlet of the container 2 is still with the Sampling line 6 connected.

The operation of the plant is as follows: To the container with liquid To fill oxygen, the filling coupling at the end 11 of the filling and venting valve is used 10 connected. As a result, the connections from the filling coupling are in this valve to the line 12 and from the extraction line 6 to the vent pipe 13. The switching valve 17 connects the downpipe 16 with the filling line 5. The through Liquefied oxygen delivered to the filling nozzle under moderate pressure flows through the filling and venting valve 10 and the line 12 into the vessel 15 and, after he has filled this, through the downpipe 16, the switching valve 17, the filling line 5 and the downpipe 25, whereby the container 1 is filled. A flow through the feed line 4 is through the oxygen supply valve, not shown or a shut-off valve, which is inserted into the consumer line 7, prevents. After the container is filled, the oxygen flows through line 27 in the lower outlet of the container 2 and fills it.

During filling, the gaseous contents of each container are over the extraction line 6 and the venting part of the filling and venting valve 10 drained; this flows out through the ventilation pipe 13. The gaseous content of the container 1 also flows out through the line 27 and the container 2. That Filling is canceled as soon as liquid oxygen escapes from the vent pipe 13 is observed. The filling nozzle is then removed. This allows the filling and Vent valve 10 return to its closed position, causing the top end the line 12 is closed and the extraction line 6 is connected to the line 14 will. When the line 12 is closed, the pressure is equal in the whole System off, and the switching valve 17 responds, closes the downpipe 16 and connects the lower end of the heat exchanger 18 with the filling line 5.

During the filling remains due to the given by the downpipe 16 Altitude of the vessel outlet a certain amount of liquefied oxygen in to the Vessel 15 back and begins to evaporate due to the atmospheric heat, whereby the resulting pressure transfers the liquid through line 12 into the heat exchanger 18 presses, where it is completely evaporated. At this point the stabilization circuit is working, that is, oxygen is evaporated in the heat exchanger 18 and flows through the switchover valve 17, the filling line 5 and the downpipe 25 into the lower outlet of the container 1. The gaseous oxygen bubbles through the liquid in this container above and flows through line 27 into container 2, where it in turn passes through the The liquid contained in it bubbles. This will mix the contents of the containers and ensured that there was no significant temperature drop from the surface occurs in the lower layers of the liquid and, accordingly, no substantial one Change in pressure if the contents of the container, e.g. B. during flight, shaken up will. In this state, the system is considered to be "stabilized".

When the system is full and the filling and venting valve 10 the extraction line 6 connects to the line 14, the back pressure on the heat exchanger 20 lifted so that one or both valves 26 and 29 are under the pressure of the Open the liquid and the pressure generating circuit begins to work. Takes it is assumed that no gas is taken from the evaporator 3, then the liquefied one Oxygen is pressed into the heat exchanger 20, where it evaporates, whereupon the gas passes through the pressure control valve 21 into the line 14 and from there through the filling and venting valve 10 and the extraction line 6 flows into the upper outlet of the container 2, whereby this is put under pressure. The pressure in the container 2 is increased via the line 27 transferred to container 1. As the pressure increases, it becomes more and more liquefied Oxygen is pressed into the heat exchanger 20, where it evaporates until it reaches the containers the required working pressure has been built up. At this pressure the pressure control valve closes 21 automatically and the system is ready for operation.

If oxygen extraction is required, the valve or od. Like. Opened in the consumer line 7. This reduces the pressure in the evaporator 3, whereupon liquefied oxygen enters the evaporator due to the gas pressure in the containers 3 is pressed in order to be evaporated and heated there before it reaches the consumer line achieved. The pressure is automatically controlled by the pressure control valve 21 maintain the pressure-generating circuit. The part of this that opens when pressure is applied Valve also relieves excess pressure in the extraction line by causing it to pass through the line 22 of the consumer line 7 can flow away. Another security is given by the relief valve in the pressure control valve 21, which is gaseous Oxygen is blown from line 14 as soon as the pressure rises unusually high. This valve is set to a higher pressure than that which closes when pressure is applied Part of the pressure control valve 21.

In tests which were carried out with this system and in which the contents of each container at successive stages during the Removal of gaseous oxygen from the evaporator 3 was measured, is determined that container 1 began to empty first, that however, before less than half of its contents were removed, so was the container 2 began to empty. From then on the emptying amount of both containers was approximate same. As a result, after a certain time, container 2 was less than half full, whereas the container 1 was emptied. The working pressure was up to the emptying of both Container kept constant. It turned out that the use of interconnection lines different lengths and the change in the relative position of the containers to each other did not materially affect these results.

The system can also be used when e.g.

1. The stabilization circuit is omitted, so there is a direct connection exists between the line 12 and the filling line 5, 2. the gas supply line22 in the economy circuit omitted and the excessively pressurized gas to the heat exchanger 20 instead this line is taken, 3. the container have filling meters, which for this purpose can be used to estimate when the filling is complete.

Fig. 2 shows a system, of which for a clearer representation only the basic features shown and in which four containers 101 to 104 are connected are. The container 101 has a lower outlet which connects to both the fill line 105 as well as with the feed line 106 upstream of the valve 107 is connected. The floor outlets the remaining containers 102, 103 and 104 are each connected to the feed line via a valve 108 106 after the valve 107 and to the upper outlet of the one preceding in the series Container connected via a line 109. The upper outlet of the last container 104 of the series is connected to a removal line 110.

The feed line 106 leads into an evaporator 111, where the liquefied Oxygen evaporates and from where it is fed to a point of consumption.

Claims: 1. Evaporation system for liquid oxygen Oxygen supply to breathing apparatus, in particular high altitude breathing apparatus, with a Evaporator to which the liquid oxygen is fed through a feed line, a filling line, a removal line with a device for draining of pressurized gas, and two or more containers for the liquid oxygen, each of which has an upper and lower outlet for the has gaseous or liquid oxygen, d u r c h marked, that the lower outlet of the first container (1 or 101) with both the filling line (5 or 105) as well as with the feed line (4 or 106), seen in the direction of flow, in front of a first valve (26 107) is connected so that the lower outlet of each of the following containers (2 and 107) 102) as well as a one that also opens at a certain fluid pressure Valve (29 or 108) with the feed line (4 or 106), seen in the direction of flow, behind the first valve (26 or 107) as well as with the upper outlet of the previous one Container and that the upper outlet of the last container in the series with the removal line (6 or 110) is connected.

Claims (1)

2. Evaporation system according to claim 1, characterized in that it has two containers (1 and 2) for the liquid oxygen. 3. Evaporation system according to claim 1 or 2, characterized in that that between the extraction line (6) and the feed line (4) a pressure generating Circuit is switched. Documents considered: British Patent Specification No. 940 749, 947 856; U.S. Patent Nos. 2,435,332, 2479070; »Engineering« magazine, 1961, August 11, p. 162.