US2645940A - Snap sampler - Google Patents

Description

July 2l, 1953 J. Kol-n. ETAL SNAP SAMPLER 2 Sheets-Sheet 1 Filed May 14, 1952 A TTORNEK J. KOHL El' AL SNAP SAMPLER July 21, 1953 Filed may 14, 1952 Patented July 2l, 1953 SNAP SAMPLER.

Jerome Kohl, Berkeley, Elliott G. Reid, Palo Alto,: and Lloyd R. Zumwalt, Lafayette, Calif.,A assignors to the United States of America as represented by the'United States Atomic Energy Commission Application May 14, 1952, Serial No. 287,662

This invention relates to an airborne device for sampling the gaseous and solid content of a radioactive cloud in such a way that a representative sample of the cloud is collected and retained in a form suitable for analysis.

It is well known that the collection of a representative sample of any aerosol is difficult and extremely susceptible to mechanical error. In general, sampling is undertaken with the inten-` tion of obtaining two types of information, the concentrationof the aerosol, and the particle size distribution of the dispersed particles. This latter type of collection is rendered particularly complicated if the particles consist of several materials having different shapes and densities as well as a wide range of size distribution.

The source of error probably lies in the fact that as the continuous phase of sampled aerosol, i. e., either air or some other gas, is drawn into the sampling device, a plurality of velocity and pressure contours exist at the entry of the` sampler. While it is not believed necessary to discuss at any length the theoretical aspects of this type of error, it will be readily seen that, because of the differences in shape and inertia of the several sizes of particles,` some sizes and shapes will be drawn into the sampler more readily than others. y t

It will therefore be apparent that it is necessary to impart motion to either the aerosol system being sampled or the system doing the sampling, in order to bring an aliquot of that system into the sample. In the case of sampling a stationary aerosol with a moving probe, it is desirable that the Vsampler actually swallow and retain a volume of the entire system, which may subsequently be analyzed.

It has been established by theory and experiment that if the sample of gasparticulate aerosol is drawn into the sampler at a velocity or rate appreciably different from thel speed `of `4the sampler entry through the system, an-unrepresentative sample will be obtained, wherein both thev size distribution and concentration of the provided a sampler comprising a sampling nozzle,

a gas tight extendible envelope for containing the sample, a tube extending from the nozzle and opening into the envelope, remotely-controlled means on the nozzle and tube for limiting vthe passage of air 'from' the nozzle into the envelope,

, 2 andv automatic means controlled by the-exten# sion of the envelope operating the remotelycontrolled means.

Since it is intended to mount such sampler on a drone aircraft which will pass through an atomic cloud, the necessity for remote-controlled and automatic operation will be imme` diately apparent. The sampler described above is intended to be mounted in the nosefof a drone aircraft, with the nozzle and tube extending forward from the aircraft into thefundisturbed airI- ahead of the disturbed boundary layer around the fuselage. Prior to collection, the gas-tight envelope is collapsed,V within a casing in the' nose of the aircraft fuselage. When the drone entersl the atomic" cloud, which consists of radioactive gases and solids', as Well `as other burst debris, a radio signal activates a remotely-controlled valve which opens the nozzle. The cloud components are then swallowed by the sampler, passing through the nozzle and tube into the collapsed is reached,the moving envelope surface trips a switch which in turn closes the valve and nozzle. In this way the collected sample is sealed within the sampler assembly and may be removed therefrom when the drone returns toits base.

It is therefore an object of the present inven`-,y tion to provide a new and improved sampling de?r vice. Another. objectv of the present invention is 'to provide a sampling device which collects and retains a known volume of a system at a controlled or predetermined rate for a controlledv or predetermined time. y `Still another object of theinvention is to provide a sampling device for collecting a sampleV from an aerosol system at a velocitysubstantially equal to the velocity at which'the device moves through the system. e A A further object of the invention is to provide a sampling device adapted for remote control operation. j n

A still further object .of the invention is to provide a sampling device having automatic or remote control shut-off means, the action ofV which is accomplished in a manner to effective 1y seal the sampler and preclude loss or pollution of the collected sample.

Still another object of the invention is to pro vide a sampling device wherein they collectedY L sample may be readily removed from the device without. loss or pollution. j

Other objects and vadvantages of the invention will be apparent in the following description and claims considered together'with the accompanying drawing inwhich: A

Figure 1 is a side elevation, partly in section, of the invention;

Figure 2 is a schematic wiring diagram of the control circuit associated With the invention as shown in Fig. 1;

Figure 3 is a detailed illustration, partly in section, of the envelope inlet, with the closure therefor in open position, of the invention of Fig. 1;

Figure 4 is a detailed illustration of the envelope inlet of Fig. 3 with the closure therefor in closed position; and

Figure 5 is a detailed illustration, partly in section, of the nozzle of Fig. l together with the closure device.

Referring to the drawing in detail, Fig. 1 in particular, there is provided a deck I I of plywood or other suitable supporting material. Such deck II is mounted upon brackets I2 (only one of which is shown) within an aircraft fuselage I3, f

bag I8 of an inert resistant material is disposed within the container I4 to receive a sample of an aerosol system.

A housing I9 is mounted about an aperture 2l in the end of the container I4 extending toward the forward portionof the aircraft fuselage I3 to support the inboard end 22 of an elongated tube 23. It will be noted that, in Fig. 1, the tube 23 extends through an opening 24 in the forward portion of the aircraft fuselage I3 which is provided with a closure member 26 suitably mounted, as by a plurality of bolts 21. To brace the tube 23 as it passes through such closure member 26, there is provided a metal sleeve 28 suitably mounted between the tube and the closure member.

A nozzle 3| engages the outboard end 32 of the tube 23 (see Fig. 5) as by threads 33 to provide an intake for the device such that the velocity of gas flowing therein is substantially equal to that of the remainder of the system beyond the sampler and aircraft. To accomplish the latter, the nozzle 3l has a tapering outer surface 34 expanding back from the direction of flightand a sloping inner surface 36 expanding in the same direction. Thus, there is provided a. smoothly expanding channel 31 for the entering aerosol system while the entire nozzle advances through the system with a substantially sharp forward edge 38 With the result that the retarding effect of friction and viscosity around the tube 23 and nozzle 3| assembly is overcome by creating a high back pressure in the channel 31.

A removable cylindrical liner 4I of an inert material is provided for insertion into the tube 23 to extend the entire length thereof. Such provision is necessary, since the aerosol passing through the tube 23 may leave contaminants which would pollute subsequent samples and the replacement of the tube 23 and associated elements would be a lengthy and expensive project.

To open and close the nozzle 3I a valve assembly 46 is mounted on the outboard end 32 of the tube 23. Two sleeve clamps 4-1 and 48 .disposed in spaced-apart relation about the tube 23 at the outboard end 32 thereof are suitably mounted in through the closure member 26.

position, as by bolts 49 and 5I, respectively, to support such valve assembly 46. The foremost sleeve clamp 41 is provided with an extended portion 52 to which a bell' crank 53 is pivotally and centrally mounted, as by a pin 54, for movement in a plane parallel to the axis of the tube 23. One end of such bell crank 53 is pivotally connected, as by a pin 56, to a valve arm 51, which at the foremost end thereof is provided with a head 58. To insure a tight seal between the forward edge 38 of the nozzle 3I and the head 58 a pad 59 of resilient material, such as rubber, is suitably mounted on the seating surface of the head. The movement of the valve arm 51 is restricted by a yoke 6I which is pivotally mounted at one end by a pin 62 extending therethrough to engage the foremost sleeve clamp 41 and is pivotally attached at the other end to the Valve arm 51 by a pin 63. The other end of the bell crank 53 is pivotally attached by a pin 64 to one end of a connector rod 66 which is extended back toward the fuselage I3 through a support 61 on the other sleeve clamp 48.

With the foregoing elements of the valve assembly in place, it Will be readily apparent that the nozzle may be opened by moving the connector rod 66 toward the fuselage I3 of the aircraft and closed by moving the connector rod in the direction of flight to force the valve arm 51 to seat the head 58 and pad 59 over the leading edge 38 of the nozzle 3|.

To maintain a normally seated position for the head 58 and pad 59 the connector rod 66 is provided with a flange 1I and a spring 12, the latter being mounted in compression on the rod between the flange and the support 61. Thus the force of the spring 12 serves to maintain the connector rod 66 in the forward position which, as set forth above, results in the head 58 being seated firmly over the leading edge 38 of the nozzle 3I.

An actuating pneumatic cylinder 16 is mounted on 'a clamp 11 fixed on the tube 23, as by bolts 18, adjacent to and forward of the sleeve 28 A shaft 19 of the cylinder 16 is provided with a yoke 8| which is pivotally connected by a pin 82 to the connector -rod 66. An air tube 83 is connected from a fitting 84 of the cylinder 16 to a fitting 86 suita'bly mounted through the fuselage I3. The inboard side of such latter fitting 86 is connected to a valve 81, having a solenoid 88 for control thereof, by another section of tubing 89. Air pressure is `applied to such pneumatic system by a conventional tank 9| of Icompressed air through an air line 92 having a pressure gauge 93 and manual valve 94.

It will be readily apparent from the foregoing that, with the pneumatic system described in operation, actuation of the solenoid 88 wil1 apply air pressure to the cylinder 16 thereby forcing the shaft 19 back toward the fuselage against the tension of the spring 12 to force the Valve head 58 away from the nozzle 3I and allow gas to enter thereinto. De-energization of the solenoid 88 closes off the pneumatic system so that the air in the cylinder 16 is exhausted and the spring 12 forces the shaft 19 and rod 66 in such direction as to return the valve head 58 to a closed position over the opening of the nozzle 3|.

To collect gases which enter the nozzle 3l and flow into the tube 23, the material adjacent the opening of the bag I8 is secured to the tube, as by a ring yclamp 96 having a take-up bolt 91. 'Ifo insure a suitable airtight connection, a bushing 98 threadably engages the inboardend of the tube 23 andthe` ring clamp 96 compresses the material adjacent the opening of the bag|8 therebetween, as shown in Figs. 3 and 4.

A second valve assembly is provided within the housing I9 and isl associated with the inboard end of the tube 23 to limit the flow of gases from the tube into the bag I8 and to confine gases therein when a satisfactory sample has been obtained. As stated previously the housing I9 serves to support the inboard end of the tube 23 and at the position of support is provided with an outwardly extended'portion |02 having a diameter greater than the diameter'of the' tube.

' A sleeve support |03, having yan insideA diameter substantially equal `to the outside diameter of the tube 23 and an outside diameter substantially equal to the inside diameter of the extended portion |02 of the housing I9, is disposed about the tube within the housing with one end I 04 thereof abutting the extended portion. The yinnermost end |06 of the sleeve support |03 is provided with a bracket |01 extended therefrom. Pivotally mounted, as by a pin |08, `on the bracket |01 is a iiapper valve |09 having a generally vertical lever portion |I| which extends through a slot I I2 in the housing I9, an arm portion I I3 .extending normally from the lever portion near the base thereof, and a ilap portion I|4 extending down from the arm portion. Thus with the pin |08 mounted `substantially at the juncture of the lever and arm portions, III and ||3, respectively, 0f the ilappervalve assembly I0 I, the flap portion ||4 may be rotated to an open and closed position with respect to the extended inboard end of the tube liner 4|. A tension spring I I6, suitably disposed between hooks I|1 and ||8 which are mounted one at the lower end of the lever portion III of the ilapper valve and the other at the opposing end wall of the housing I9, is provided to maintain a normally closed position of the nap portion I I4. It will be noted that because of the yclamped seal between the liner 4I of the tube 23 and the material of the bag I8 a layer of such bag material lies between the flap |I4 'and the liner when the valve assembly 0| `is in the closed position. Thus to insure a tight, though abrasionless, seal a pad I2|, of sponge rubber or the like, is suitably mounted on the flap i I4 at its contact side.

To actuate the Valve assembly |0| there is provided a solenoid |26, having a plunger |21, suitably mounted within the housing I 9 substantially transverse to the lever portion III of the assembly. A connector arm |28 is mounted on the upper part of the lever III, as by a nut |29, with one end thereof pivotally connected by a pin I3I to a link |32 which is, in turn, pivotally connected by a pin |33 to the plunger |21. To limit the movement of the lever I of the valve assembly |0I, there is provided a stop mechanism |36 mounted upon the housing I9 in line with the slot I I2 and having a central shaft |31 which may be adjusted in accordance with a conventional micrometer element |38. The purpose of the latter will be more fully explained hereinafter.

In operation, it will be noted that actuation of the solenoid |26 is such as to pull on the plunger |21 which rocks the valve assembly |0I about 6. Thus there has been provided Va valve assembly 48 for opening the normally closed end of the nozzle 3| and a valve assembly |0| for opening the normally closed inboard end of the tube 23. To close such valves 46 and I0| there is also provided-'a triggering mechanism I4| which is operable, fat such time las a representative sample has been obtained, to close the v-alves and retain; the collected/sample. A pedal plate I 46 is disposed within the container I4 at the end thereof opposing the intake end. Such pedal |46 is attached to the bottom wall of the container I4 (see Fig. 1) by a hinge |41 and is extended upwardfand slightly beyond a point where alimiting bolt |48 is extended transversely therethrough to engage a nut |40 at-the outsideof the rear wall of the container. A compression spring the pin |08 to force the flap ||4 away from the liner 4| and allows gas to pass therefrom intov |5|1gdisposed about thebolt |48 between the wall of the container I4 and the pedal |46 maintains a normal lspring-loaded position forY the pedal.v A normally-closed single position mioroswitch |52, suitably mounted on the rear Wall of the container |4,` is disposed with the fingerr |53y thereof adjacent the pedal |46. From the fore- `going it will be readily 4apparent that as the bag |8 .expands to ll;the container I4, the upper portion of the pedal |46 will be forced toward the microsw-itch |52 and eventually depress the nvger |53 thereof to open the mjcroswitch. With the lsolenoids 88 yand |26 suitably connected inl a circuit with the microswitch |52, las described hereinafter, the solenoids are de-energized to close the valve assemblies 46 and |0I A suitable actuating or control circuit, as shown in Fig. 2, is provided for the device described in theforegoing. A pair of conventional radio receivers 20| and 202, preferably tuned to different bands of frequency, are provided with the inputs thereof connected to suitable antennae 203 and 204. While a single receiver is adequate for the purposes of theinvention, an additional receiver is utilizedto insure proper operation from a remote side when the device is mounted in a drone aircraft. The output of such receivers 20| and 202 is respectively connected across two solenoids 20-6 and 201 of a relay 208, in such a manner that anr output signal of either receiver will energize the respective solenoid to close a normally open contact 2 I or 2 I 2, respectively. Such contacts 2|I and 2| 2 are connected in parallel with one side thereof connected to the positive terminal of a conventional power supply 2|3 through a fuse 2|4. The other side of the contacts 2|| and 2|2 is connected to the normally closed mieroswitch |52 which, in turn, is' con-v nected to a'solenoid ZIB of a relay 2 I1. The other side of such solenoid 2I5 is connected to the grounded negative terminal of the power supply 2| 3. Thus when either of the `contacts 2I|, 2|2

are closed, a completed circuit is formed to enerof the relay 208 and the microswitch |52. The

latter connection serves to maintain the solenoid 2|6 of the relay 2 I1 energized after the termination of the signal output of the receiver 20| or 202 and only actuation of the microswitch |52 lwill break the circuit and de-energize the solenoid. A single pole lsingle throw switch 22| connected in'parallelwith such latter connec- Such contacts 2|8 and 2|'9 are connected tion serves a similar purpose when manual operation is desired. The other'side of the contact 2I9 is connected to one contact of the central pole of a triple pole double throw switch 226. The center contact of the central pole of such switch 226 is connected to one contact of an outside pole and further to one side of nozzle valve control solenoid 08, the other side7 of which is connected to the grounded negative terminal of the power supply 2 I3. The center contact of the above-referenced outer pole is connected through a quick disconnect plug 23|, mounted rigidly upon the closure member 26, to one side of the apper valve control solenoid |26, the other side of which is connected to the `grounded negative terminal cf the'power supply 2|3. One contact of the other outer pole of the switch 226 is connected to the center contact thereof and further to the grounded negative terminal of the power supply 2|3. The foregoing connections of the switch 226 should be made so that with the switch closed in one position, to be referenced as the ll position, both of the solenoids 88 and |26' are energized toY open the nozzle valve 46 and the flapper valve |09, respectively, in response to a signal to one of the receivers or 202.

VThe remaining contacts, to be referenced as the empty position, of the switch 226, all at one end thereof, may then be connected to an auxiliary power supply 24| for use on the ground when the power of the plane is not available for use as the power supply 2|3. Such auxiliary power supply may comprise a series of batteries 246 connected to two contacts of a double pole single throw switch 241 the other two contacts ofY which are connected to contacts of the switch 226, the nozzle valve control solenoid 80 may be energized thereby. A single pole single throw switch 246v is connected from the batteries 246 to a contact ofthe switch 226 so that the apper valve control solenoid |26^may be suitably energized.

As stated previously, it is necessary that the sample of gas particulate aerosol be drawn into the sampler at a rater substantially the same as the speed of the sampler through the system. To accomplish such result there' is provided a static tube suitably mounted on a bracket 252 suspended from a clamp fittingv 253 disposed about the 'tube 23 between the two forward sleeve clamps 41 and 48; Such static tube 25| is disposed parallel to the nozzle 3| and extends forwardofA the' aircraftl fuselage I3 substantially the same distance. Tubing 256 is connected to the static tube 25| and extends back into the aircraft `(not shown). A static pressure tap is provided at the entrance of the nozzle 3| by an orifice 251, see Fig. 5, therein which is connected by tubing 258 to an'internal portion of the aircraft (not shown). Both sections of connectingtubing are then connectedV to a conventional manometer (not shown) to indicate pressure dif ferential between that of the static tube 25| and theA orifice 251. It will now be noted that the flapper valve'assembly |09 is such that the rate of flow of gas from the tube liner 4| into the bag |8 is readily controllable. Thus, anV adjustment of the micrometer stop |36, which determines the maximum open position of the ap' |'4 with res'peot t@ the tube liner 4 I, may be made to equal' The ize the pressure at the two noted points. position of the micrometer stop may be calibrated in advance so that representative samples maybe collected'withouty adjustment thereof during the sampling process.

In operation, the sampler mounted in the nose of a drone aircraft, which may be of the bomber type". In this manner, the box I4` con-v taining the bag |8 may be mountedA in the bombardiers compartment in the nose of the aircraft, with the tube 23 and nozzle 3| extending forward into the undisturbed air, as previously set forth. Prior to the take-off, the nozzle' valve assembly 46 and the dapper valve assembly |09are closed, the micrometer stop |36 on the fi'apper valve assembly is preset, the triple pole double throw switch 226 is placed in the l1" position, and the bag I8 is deflated., The microswitch |52 within the container |`4 is closed and the relays 208 and 2|1 are de-energized so that the contacts thereof are open. I v

As" the drone aircraft enters the atomic cloud; and it is desired to obtain a sample thereof, a radiosignal is transmitted from a suitable transmitter (not shown) located at a safe position. Such' signal is picked up by the antennae 203 and 204 and, according to the frequency thereof, passes through the receiver 20| or 202 tuned to the proper frequency. An output signal of one of the receivers 20| and 202 energizes one of the respective solenoids206 and 20'1 of' the relay 208 which, in turn, completes the circuit through the solenoid 2|6 of the second relay 2|1. When the contacts' 28 and 2|9 of the second relay 2|1 a circuit is completed to maintain solenoid 2|6 thereof energized after the termination of the transmitted radio signal. The closing of the contact 2|9 of the relay 2|1 results in energization of the nozzle valve control solenoid 8B and the lapper valve control solenoid |26. The core of the nozzle valve control solenoid 88 then moves to open the pneumatic valve 81 which results in compressed air of the tank 3| forcing the shaft B in :Such a direction as to move the valve head E8 away from the opening of the nozzle 3|. At the same time as the foregoing occurs, the flapper valve control solenoid moves the plunger |21 thereof to open the flapper valve assembly |09 to the limit permitted by the previous setting of the micrometer stop |36. Under such conditions gasY particulate aerosol of the atomic cloud owsinto the nozzle 3|,` at a rate substantially equal to the speed of the aircraft through the cloud, through the tube Iliner 4|, and into the bag |8. Expansion of the bag |8 within the container I4 is permitted by the plurality of apertures I6 therein and continues until it is restrained by the walls thereof. At such time as the bag I6n is inflated to fill the container, the pressure of the-bag against the pedal |46 becomes greatenough to force such pedal against the arm |53 of the microswitch |52 which in turn opens the circuit energizing the solenoid of the relay 2 1. At such time the nozzle valve control solenoid 88 and the dapper valve control solenoid |26 becomel fle-energized permitting the springs '.2 andv ||6 to respectively close the valve assemblies 46 and |09 so that the sample obtained is retained.

When the drone aircraft carrying the sampler has landed at its home base, the sample may be withdrawn by' connecting the auxiliary` power supply 24| to empty position of the switch 226 inthe manner previously described, closing the switch to such position, and then closing the double pole single throw switch 241. The closing of therlatter switch 241 energizes the nozzle valve control solenoid 88 to open the nozzle valve assembly 46. With thenozzle 3| open, a vacuum hose and system (not shown) may be attached thereto. Next, the single pole single throw switch 248 is closed which energizes the dapper valve control solenoid |26 to open the fiapper valve assembly |09 and permit the transfer of the sample in the bag I8 to another container for analysis. Should the bag I8 and tube liner 4I become contaminated, it will be readily apparent that the same may be readily and simply removed and replaced. f

While the salient features of the present invention have been described in detail with respect to one embodiment it will, of course, be apparent that numerous modifications may be made within the spirit and scope of the invention to the exact details shown except insofar as they may be defined in the following claims.

What is claimed is: p

1. In an airborne device for sampling the gas cous and solid content of a radioactive cloud, the combination comprising an air-tight bag disposed Within an aircraft, an elongated tube extending from said aircraft into undisturbed atmosphere in front thereof, said bag being attached to said tube at the inboard end thereof, a tapered nozzle mounted on the outboard end of said tube, a movable closure member mounted on said nozzle, and means mounted at the in'- board end of said tube for controlling the rate of flow of gas into said bag.

2. In an airborne device for sampling the gaseous and solid content of a radioactive cloud, the combination comprising a container mounted within an aircraft, an air-tight `bag disposed within said container and having a single openy ing, an elongated tube supported at one end by' said container with the opening in saidA bag sealed about such tube end, said tube projecting forward of said aircraft to atmosphere undisturbed thereby, a nozzle having an inwardly and outwardly tapered forward portion mounted on the outboard end of said tube, a movable closure member mounted on said tube for opening and closing said nozzle, and an adjustable valve mounted at the inboard end of said tube to provide control of the rate of gas flow into said bag.

3. In an airborne device for sampling the gaseous and solid content of .a radioactive cloud, the combination comprising a vented container adapted to be mounted within 1an aircraft, a collapsible air-tight bag ydisposed within said container having an opening therein, an elongated tube supported at one end by said container with the opening of said bag sealed to such tube end, said tube being extended forward of said aircraft into air undisturbed thereby, a nozzle mounted on the outboard end of said tube and having the forward portion thereof divergently tapered, a movable closure mechanism mounted on said tube for opening and closing said nozzle, an adjustable valve mounted at the inboard end of said tube to provide control of the rate of gas flow into said bag, remotely actuated means connected to said mechanism and said valve for opening the same, and means disposed within said container and connected to said mechanism and valve for closing the same in response to the degree of inaton of said bag.

4. In an airborne device for sampling the gaseous and solid content of a radioactive cloud, the combination comprising a ventedA container adapted to be carried by an aircraft, a collapsible air-tight bag disposed within said container and air, a removable liner disposed within said tube and said valve for opening the same, and means 'disposed within said container and connectedto said mechanism and valve for closing the same in response to the degree of inflation of said bag.

5. In an airborne device for sampling 'the gaseous and solid content of a radioactive cloud, the combination comprising an air-tight bag disposed within an aircraft, an elongated tube extending from said aircraft into undisturbed air in front thereof, said bag being attached to said tube at the inboard end thereof, a nozzle mounted on the outboard end of said tube, valve means mounted on saidtube and including a head bearing arm adapted to seat said head over the opening of said nozzle, piston means coupled rto said valve means for opening said nozzle, a source ofl compressed air, a solenoid actuated valve interconnecting said source `of air and saidA piston for control of the latter, a solenoid operated rflapper Y valve mounted at the inboard end of said tube for controlling the rate of gas flow into said bag,

`circuit means. including said solenoids and having an opening therein, an elongated tube adapted to be remotely operated.

6. The combination of claim 5 wherein said vcircuit means is further characterized by a first relay adapted to be energized by a signal received from a remote position, a second relay adapted to be energized in response to energization of said first relay and having means connected thereto to maintain such energized state, said solenoids being connected to contacts of said second relay for energization thereof.

7. The combination of claim 5 wherein said valve means and said solenoid operated flapper valve are further characterized by a compression spring mounted to return said valve means from an open to a closed position, and a tension spring mounted to return said fiapper valve from an open to a closed position.r

8. vThe combination of claim '7 wherein said solenoid operated iiapper valve is further characterized by a pivotally mounted arm bearing a nap adapted to close the inboard end of said tube and having an extended portion, and an adjustable stop mounted adjacent the extended portion of said arm to limit the open position of said flap with respect to the inboard end of said tube and thereby control the rate of gas flow into said bag.

LLOYD R. ZUMWALT. ELLIOTT G. REID. JEROLHT KOI-IL.

References Cited in the file of lthis patent UNITED STATES PATENTS Number Name o Date 2,452,224 C'ollett, Jr Oct. 26, 1948 2,488,810 Easterday I- Nov. 22, 1949 FOREIGN PATENTS Number Country Date 351,584 Great Britain July 2, 1931

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