US 2943490 A
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Description (OCR text may contain errors)
July 5, 1960 D. F MELTON 2,943,490
AIR SAMPLING DEVICE Filed Feb. 17, 1959 2 Sheets-Sheet 1 l8 as 'V/JJEWZ J54 26 I DOIZQkZFMZZOQ N R July 5, 1960 D. F. MELTON 2,943,490
AIR SAMPLING DEVICE Filed Feb. 17, 1959 2 Sheets-Sheet 2 fiOWMEINVENTOR i SAMPLING DEVICE Filed Feb. 17, 1959, Ser. No. 793,940
16 Claims. (Cl. 73-4215) This invention relates to the collection of high altitude atmospheric air samples.
It is an object of the invention to provide improved apparatus and methods for collecting an air sample at high altitude ambient pressure and bringing the sample intact to earth.
Another object is to collect a relatively large air sample at the collection altitude in a large container, tansier the sample to a relatively small and rugged container, and deliver the latter to earth.
Further objects and advantages of the invention will appear as the description proceeds.
The invention will be better understood on reference to the following description and the accompanying schematic drawings, wherein:
Fig. 1 is an elevational view of a high altitude atmospheric air sample collecting system according to one form of the invention.
Fig. 2 shows the mechanism by which high altitude air is aspirated into the lower bag.
Fig. 3 shows the bags fully inflated with the mixture of bottle gas and high altitude air.
Fig. 4 shows mechanism for sealing the lower bag at the end of the inflation of the bags.
Fig. 5 shows the inflated bags with the lower one sealed at the bottom.
Fig. 6 shows the descent-control mechanism.
Fig. 7 is a top plan view taken as indicated by the line 77 in Pig. 6.
Fig. 8 shows mechanism for sealing the upper bag.
Fig. 9 is a sectional view taken as indicated by the line 9-9 in Fig. 8.
Fig. 10 shows the bags just before the upper one is sealed.
Fig. 11 shows the bags with the upper one sealed.
Fig. 12 shows a modified system.
Fig. 13 shows a further modified system.
Referring now more particularly to the drawings, an illustrative embodiment of the invention is shown schematically in Figs. 1 to 11 and comprises a balloon system 10 including a tow balloon envelope 12 having at the top a descent-control valve 14 (Figs. 1, 6, and 7) controlled by mechanism carried by a box 15 suspended by load lines 16 from the envelope. Suspended by load lines 17 from the box 15 is a drag chute 17a which, by load lines 17b, suspends a small bag 18 by which the high altitude (100,000 ft. more or less) air sample is to be delivered to the ground. A large bag 20 is connected to the small bag 18 by a flexible tubular neck 22, the three constituting a receptacle. A box 23 suspended by load lines 24 from the bag 18, and suspending the bag 20 by load lines 25, contains a cord noose 26 (Figs. 3, 5, 8, 10, and 11) about the neck 22, and mechanism for tightening the noose to choke the neck closed. The bottom of the bag 20 has a flexible tubular inlet 28 choked closed by a cord loop 30 (Fig. 1) passing through a squib 32. The inlet 28 passes through 2,943,490 Patented July 5, 1960 a box 34 suspended at 35 from the bag, the box containing a cord noose 36 (Figs. 3, 4, 5, 8, 10, and 11) about the inlet, and mechanism for tightening the noose to choke the inlet closed. An injector 38 (Figs. 1 and 2) which may be formed of connected truncated hollow cones is suspended by load lines 39 from the box 34 and at its upper end projects into the bottom of the inlet 28. A high pressure gas bottle 40 (Figs. 1 and 2) is suspended at 41 from the bottom of the injector 38 and has a nozzle 42 projecting into the bottom of the injector 38, and a valve 43 controlled by mechanism in a box 44 which may also carry the control mechanism for the squib 32. Suspended by load lines 46 from the bottle 40 is a box 49 containing a radio beacon for tracking. An antenna 50 is suspended from the box 49.
-In preparation for launching the system 10, the descent-control valve 14 is closed, the noose 26 is loose about the neck 22, the bags 18 and 20 are deflated at the launching site or have arrived there in deflated condition, the inlet 28 is choked closed by the loop 30 and is loosely surrounded by the loop 36, and the bottle valve 43 is closed. Enough lift gas is introduced into the envelope 12 in any suitable manner (as by means of an inflation tube (not shown) which is then tied closed) to give the system 10 the desired rate of ascent (for example, 1000 ft./min.) enabling the system to reach collection altitude promptly. Fig. 1 shows the appearance of the soaring system 10 at about collection altitude just before collection starts.
When the system 10 reaches the desired collection altitude, which may be its ceiling (floating) altitude, (a) the squib 32 is caused to fire, cutting the loop 30 so that the inlet 23 is unchoked, and (b) the bottle valve 43 is caused to open, whereupon gas issues from the nozzle 42, entering the injector 38 and aspirating atmospheric air through the inlet 28 and into the bags 20 and 18. The flow continues until both bags 18 and 20 are full (the excess gas of course overflowing into the atmosphere) (Fig. 3), whereupon the noose 36 (Fig. 4) is caused to contract, choking the inlet 28 closed (Fig. 5), and then the descent-control valve 14 is caused to open (dot-dash lines, Fig. 6), allowing lift gas to escape from the envelope 1 2 to initiate descent of the system 10.
As the descent progresses, the mixture of high altitude air and bottle gas trapped in the bags 18 and 20 is progressively compressed by the increasing ambient atmospheric pressure, so that the lower bag 20 becomes increasingly slack as the part of the mixture which is therein is forced upward into the upper bag 18 due to the natural tendency of the lower bag to collapse and the dynamic pressure of ambient air against the lower part of the lower bag, and also due to the solar heat which warms and therefore tends to render the mixture less dense than the outside (ambient) air. This transfer from the large bag 20 to the small bag 18 can be enhanced by using a lighter-than-air bottle gas, such as helium, so that even in the absence of solar heat the mixture will be less dense than the outside air.
At some relatively low altitude (for example, 10,000 it), when all or substantially all of the mixture is in the small bag 18 so that the bag 20 is collapsed (Fig. 10), the noose 26 is caused to contract, choking the neck 22 closed (Fig. 11), thereby sealing the mixture in the small bag. When the system 10 reaches the ground, the small bag 18 may be cut free and transported to the laboratory, where the air sample can be separated from the mixture by standard laboratory techniques and analyzed.
Inasmuch as the volume of a given mass of atmospheric air varies approximately inversely with atmospheric pressure, and atmospheric pressure decreases with increasing altitude, a given mass of air occupies a much larger volume at high altitudes than it does at sea level. The size of the large (lower) bag 20 is therefore determined by the volume of the predetermined mass of air to be collected at the collection altitude, and the size of the smaller (upper) bag 18 is such as tohold the same mass of air at ground level.
The envelope 12, the large bag 20, the neck 22, and the inlet 28 may be made of a suitable film material such as polyethylene. The small bag 18 is preferably tough, to withstand impact and ground abrasion and contact with sharp objects, and handling, and may be suitably made of some such material as Fiberthin, a neoprene-coated nylon.
The bottle nozzle valve 43 may comprise a valve plate 52 having a passage 54 and connected to the plunger of a solenoid 56 in series with a battery 58 and a low pressure switch 60 (Fig. 2), all preferably carried in the box 44. Until the solenoid 56 is energized, the plate 52 closes the nozzle 42. The squib 32 may be controlled by its own low pressure switch and battery, or may be connected in parallel with the solenoid 56 as shown. The switch 60 is set to close when collection altitude is reached, to fire the squib 32 and pull the valve plate 52 to the position in wihch its passage 54 registers with the nozzle bore 62, releasing gas from the bottle 40.
The noose 36 may comprise linked cords (Fig. 4), and the noose-actuating mechanism 63 may comprise motordriven drums 64 connected to the respective cords and powered by a battery 66 and controlled by a switch 68.
The switch 68 could be a timer switch set to close when the predetermined bag-inflating period has terminated, or it could be a pressure switch set to close when the bottle 40 is exhausted. When the switch 68 closes, the drums 64 are turned in directions to contract the noose 36 tight about the inlet 28.
The descent-control valve 14 may be of the form illustrated in Figs. 6 and 7. The envelope 12 has a top opening at which is fastened a ring 72 providing at its under surface a valve seat 74. A valve disc 76 below the seat 74 is biased into closed position against the seat by springs 78 connecting the disc to a bracket 80 over and secured at its ends to the ring. Insulated from and supported by the bracket 80 is a solenoid 82 having a plunger 84 over the disc 76. The solenoid 82 is connected in series with a battery 86, a rate-of-descent sensor switch 88, and a timer switch 90, the latter three being carried in the box 15, and the wiring from the solenoid extending outside the envelope 12 (Fig. 1). The timer switch 90 is preset to remain open until after the system reaches the predetermined ceiling altitude and enough time has elapsed to insure that the bags 18 and are filled. The sensor switch 88 is set to open only in the case of excessive rate of descent, so that it is normally closed. Once the timer switch 90 closes, it remains closed. When the timer switch 98 closes, and the sensor switch 88 is closed, the solenoid circuit closes, whereupon the solenoid plunger 84 is thrust downward, unseating the disc 76 (see dot-dash lines, Fig. 6), opening the valve 14, and thus initiating the descent of the system 10'.
The noose 26 may comprise linked cords (Fig. 8), and the noose-actuating mechanism 92 may comprise motordriven drums 94 connected to the respective cords and powered by a battery 96 and controlled by a delayed action high pressure switch 98, such as that illustrated in Figs. 8 and 9. The switch 98 may comprise an anero-id bellows 100 to whose movable wall 102 is connected a pivoted arm 104 which, until a high altitude is reached, rides on a bar 106 connected to an insulator plate 108 having at its low altitude end a conductor surface 110. When the high altitude is reached, the 104 snaps down onto the plate 108 and then rides thereon, and, at the predetermined low altitude, at which all or practically all of the mixture is contained in the upper bag 18 (Fig. 10),
the arm makes contact with the surface 110, closing the drum motor circuit, whereupon the drums 94 turn in directions to contract the noose 26 (Fig. 11).
A modified system, shown at in Fig. 12, resembles the system 10 except that: the injector, bottle, and control therefor are replaced by a centrifugal blower 122 whose intake 124 communicates with the atmosphere and whose discharge end 126 is secured in the bottom of the inlet 28, a blower-controlling timer or low pressuer switch 128 which is preset to close when the system reaches collection altitude, and may control the squib 32, and a battery 130, all housed with the squib control mechanism in a box 132 suspended by load lines 133 from the box 34; and the single neck connecting the bags, and the neck control, are replaced by a perforated hose 134 secured at its upper end to the top of and extending a substantial distance down in the bag 20, a lower neck 136 extending up from the hose, an upper neck 138 depending from the bag 18 and surrounded by a noose 26 hidden by, and controlled by a timer switch 139 and battery 139a housed in, a box 13912 suspended by load lines 1390 from the bag 18, a centrifugal blower 140 whose intake and discharge ends are respectively connected to the necks 136 and 138, a delayed action high pressure switch 142, of the same type as that shown at 28, for controlling the blower, and a battery 144, the blower, switch 142, and battery 144 being carried in a box 146 suspended by load lines .148 and suspending, by load lines 150, the bag 20. The box 49 is suspended by load lines 152 from the box 132.
At the collection altitude the switch 128 closes, firing the squib 32 and thus unchoking the inlet 28, and starting the blower 122 to drive atmospheric air into the lower bag 20. When the bag 20 is filled, the switch 68 (Fig. 4), which in this case is preferably a timer switch, is closed, whereupon the drums 64 are operated to choke the inlet 28 closed, and the descent-control valve 14 opens to initiate descent of the system 120. As the descent progresses, the air in the bag 20 proceeds to compress as noted above in connection with the system 10. When the system 120 reaches some selected low altitude, say 10,000 ft., the high pressure switch 142 closes, starting the upper blower 140, which transfers the air from the large bag 20 to the small bag 18. The volume of the small bag 18 is tailored to hold at this transfer altitude all of the sample contained in the large bag 20. On the completion of the transfer, the timer switch 139 closes, causing the drums 94 to operate to choke the upper neck 138 closed.
Inasmuch as a centrifugal blower is inherently self-bypassing, there is no need for turning it off when its work is done. It can be allowed to run until the battery is exhausted.
The purpose of the hose 134 is to prevent the film material of the lower bag 20 from being sucked by the upper blower 140. The hose 134 is of a character which may flex but will not collapse to the extent of shutting ofr' flow therethrough.
A further modified system is shown at in Fig. 13, and comprises, in addition to the envelope 12 and descent control valve 14 and control therefor, a box 162 (dotdash lines) suspended by load lines 163 from the drag chute 17a and carrying a rigid high compression container 164 connected by a tube 166 to a high pressure compressor 168 controlled by a delayed action high pressure switch 170, of the type shown at 98, and a cut-off timer switch 172, and powered by a battery 174, the tube having a valve 176 controlled by a high pressure switch 178. The intake of the compressor is secured to the lower neck 136, the structure therebelow being the same as in the system 120.
In the system 160, the container 164 and bag 20 are evacuated and the inlet 28 is choked closed by the squib loop 30 prior to launching. At the collection altitude the squib 32 is firedto unchoke the inlet 28, and the blower 122 is started. When the bag 20 is filled, the drums 64 (Fig. 4) are operated to choke the inlet 28 closed. Then the valve 14- opens and the system 160 descends. During the descent the air sample in the bag 20 is progressively compressed. At some suitable low altitude, say 10,000 ft., the switch 170 closes, the cutoff timer switch 172 being then closed, starting the com-- pressor 168, which proceeds to transfer the air sample from the bag 20 to the container 164. The compressor 168 is stopped by the timer switch 172. when the transfer is complete shortly before impact, whereupon the switch 178 closes, to close the valve 176, preventing escape of the air sample from the container 164.
The container 164 is made tough and rugged to withstand impact, ground abrasion, contact with sharp obiects, and handling.
Blowers and compressors inherently have a maximum compression ratio which is considerably less than the ratio required to compress high altitude air into a required small volume, for example, 10,000 to 1. Inasmuch as the ambient pressure is low at high altitudes, many stages of compression, of great weight and requiring a large amount of power, would be necessary at high altitude to compress the sample into a small container. Where the compressor is used, the compressor is able to operate at nearly ground pressure, so that the weight and power required are relatively small.
Where bags are used in the several systems disclosed it is necessary to move air into the bags with only enough pressure to fill out the bags.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
1. Apparatus for capturing a sample of high altitude atmospheric air, comprising an exhausted receptacle having a small compartment and a relatively large compartment, the large compartment having a closed inlet, means for carrying the receptacle from the ground to a predetermined high altitude, maintaining it at that altitude, and carrying it back to the ground, means for opening the inlet when the receptacle is at the high altitude, means for inflating the large compartment with a sample of atmospheric air at the high altitude, means for closing the inlet when the sample is in the large compartment, means for transferring the sample to the small compartment at predetermined low altitude, and means for sealing the small compartment from the large compartment when the transfer is substantially complete.
2. The structure of claim 1, characterized in that the small compartment is of rugged construction capable of withstanding impact, ground abrasion, and handling.
3. The structure of claim 1, characterized in that the receptacle is formed of film and is collapsed when exhausted.
4. The structure of claim 1, characterized in that the inflating means comprises means for aspirating air into the inlet.
5. The structure of claim 1, characterized in that the inflating means comprises a blower.
6. The structure of claim 1, characterized in that the large compartment is formed of film and is collapsed when exhausted.
7. The structure of claim 1, characterized in that the transferring means comprises a blower.
8. The structure of claim 1, characterized in that the large compartment is formed of film and is collapsed when exhausted, together with bafile means connected to and projecting into the large compartment for preventing the film from being sucked by the transferring means to a position in which the film would block the transfer.
9. The structure of claim 1, characterized in that the receptacle is formed of film and is collapsed when exhausted, and the inflating and transferring means are blowers.
10. Apparatus for capturing a sample of high altitude atmospheric air, comprising a collapsed exhausted film receptacle comprising an upper compartment and a lower compartment several times larger than the upper compartment, the lower compartment having a closed bottom inlet, a balloon connected to the receptacle for carrying it to and maintaining it at a predetermined high altitude, means for opening the inlet at the high altitude, means for inflating the receptacle through the inlet with a sample of atmospheric air at the high altitude, means for closing the inlet at the high altitude when the receptacle contains the sample, means for causing the balloon to descend when the receptacle contains the sample, the weight of the lower compartment and the dynamic drag of the ambient atmospheric air against the downwardly facing part of the lower compartment being operative during descent to collapse the lower compartment and transfer the part of the sample therein into the upper compartment, the ratio of the volumetric capacity of the receptacle to that of the upper compartment being substantially equal to the ratio of the atmospheric pressure at the low altitude to the atmospheric pressure at the high altitude, so that at the low altitude the transfer is substantially complete, and means for sealing the upper compartment from the lower compartment when the transfer is substantially complete, the upper compartment being of rugged construction to withstand impact, ground abrasion, and handling.
11. Apparatus for capturing a sample of high altitude atmospheric air, comprising exhausted communicating upper and lower compartments, the upper compartment being a relatively small rigid high pressure container of rugged construction to withstand impact, ground abrasion, and handling, the lower compartment being formed of film and being collapsed and having a closed inlet, a balloon for carrying the compartments to and maintaining them at a predetermined high altitude, means for opening the inlet at the high altitude, means for inflating the lower compartment with a sample of the high altitude air through the inlet when the inlet is open, means for closing the inlet when the lower compartment contains the sample, means for causing the balloon to descend when the lower compartment contains the sample, a high pressure compressor between the compartments for transferring the sample to the upper compartment at a low altitude, and means for sealing the upper compartment from the lower compartment when the transfer is substantially complete.
12. The structure of claim 11, characterized in that the volumetric capacity of the upper compartment is a small fraction of the volume of the sample at the high altitude.
13. The structure of claim 11, together with baflie means extending from the exit of and a substantial distance into the lower compartment for preventing the film of the lower compartment sucked by the compressor from obstructing the exit.
14. Apparatus for capturing a sample of high altitude atmospheric air, comprising an exhausted receptacle having a closed inlet, means for carrying the receptacle from the ground to and maintaining it at a predetermined high altitude and carrying it back to the ground, means for opening the inlet when the receptacle is at the high altitude, means for inflating the receptacle with a sample of atmospheric air at the high altitude, means for closing the inlet when the receptacle contains the sample, and means for sealing an intermediate part of the receptacle at predetermined low altitude, the ratio of the volumetric capacity of the entire receptacle to that of the portion of the receptacle above said intermediate part being substantially equal to the ratio of the atmospheric pressure '7 at the low altitude to the atmospheric pressure at the high altitude.
15. The structure of claim 1, characterized in that the large compartment is for-med of film and is collapsed When exhausted, and 'baffle means extending from the exit of and a substantial distance into the large compartment for preventing the film from collapsing into exit-obstructing position before the transfer is substantially complete.
16. In a method of the character described, the steps 10 2,906,125
8 of collecting a sample of air at high altitude, carrying the sample to a lower altitude Where the volume of the sample is a small fraction of its volume at the collection altitude, sealing the sample in close confinement at the lower altitude, and carrying'the sealed sample to the ground.
References Cited in the tile of this patent UNITED STATES PATENTS Jewett Sept. 29, 1959