US3216246A - Atmospheric fall-out collector - Google Patents

Description

Nov. 9, 1965 E. BLONDEAU ETAL 3,216,246

ATMOSPHERIC FALL-OUT COLLECTOR Filed Feb. 4, 1963 4 Sheets-Sheet 1 Nov. 9, 1965 E. BLONDEAU arm. 3,

ATMOSPHERIC FALL-OUT COLLECTOR Filed Feb.. 4, 1963 4 Sheets-Sheet 2 FIG. 2

I Nov. 9, 1965 E. BLONDEAU ETAL 3,216,246

ATMOSPHERIC FALL-OUT COLLECTOR Filed Feb. 4, 1963 4 Sheets-Sheet 3 Nov. 9, 1965 E. BLONDEAU ETAL 3,215,246

ATMOSPHERIC FALL-OUT COLLECTOR Filed Feb. 4, 1963 4 Sheets-Sheet 4 United States Patent 3,216,246 ATMGSPI-ERIC FALL-OUT COLLECTOR Emile Biondeau, Paris, Andi- Doury, Vaucresson, and

Henri Francois, Paris, France, assignors to Commissariat a lEnergie Atomique, Paris, France Filed Feb. 4, 1963, Ser. No. 255,809 Claims priority, application France, Feb. 9, 1962, 887,544; Dec. 5, 1962, 917,654 11 Claims. (Cl. 73-170) This invention relates to means for selectively collecting precipitated or sedimented atmospheric dusts, particles or fall-out substances.

This invention is concerned more particularly but not exclusively with an apparatus for collecting radio-active fall-out at a predetermined place and during a predetermined time period, and to maintain the collected sub? stances under conditions permitting adequate measurements to be made at any time.

It is known for this purpose to use as a rule a tray coated With an adhesive substance on which the dust particles are retained and can subsequently be analysed as desired. In order to collect fall-out samples of a volume sufficient to permit the necessary comparisons, it is desirable to dispose this tray in an open space; therefore, the tray is also subjected to atmospheric precipitation, so that rain notably will wash out the adhesive surface and carry along the particles previously deposited thereon. Moreover, many atmospheric dusts retained by the rain drops are liable to escape the measurements. Under these conditions, this method requires a constant supervision (which may constitute a serious inconvenience if the selected location is rather isolated) and moreover it precludes the possibility of making continuous and accurate measurements.

The present invention provides an atmospheric fall-out collector designed notably for controlling continuously radioactive atmospheric fall-out substances or dusts and adapted to avoid the drawbacks set forth hereinabove.

This collector comprising a substantially vertical duct having a gauged aperture at its upper end, and a funnel communicating with a precipitation-receiving container, is characterized in that it comprises between said duct and said funnel a surface coated with an adhesive substance for retaining dry fall-out substances, and a retractable member adapted to protect said surface against atmospheric precipitation and to guide said precipitation toward said funnel, the movements of said retractable member being controlled by means responsive to a precipitation detector.

According to a preferred form of embodiment of this invention said retractable member is a convex member rotatably mounted about the spindle on which said adhesive surface is mounted.

The means controlling the movement of said retractable member comprise preferably an electromotor adapted to be energized through the combined action of a cam solid with the spindle carrying said member and of said precipitation detector through suitable electric circuit means. This precipitation detector may consist for example of a condenser comprising a plurality of plates so imbricated that the drops of rainwater will short-circuit any pair of adjacent plates of opposite polarities; in this case the resistance of the dielectric device is in parallel with the water resistance.

The device may be supplied with electric current either from the mains or from a storage battery, according to the specific conditions of operation and to the site in which the collector is to be operated.

The precipitated dry fall-out substances are separated as follows:

In dry weather the concave surface of the aforesaid retractable member is directed upwards and the dust parice ticles penetrating into the apparatus through the upper aperture are retained by the adhesive coating.

When the rain begins to fall, the retractable member is turned upside down so that its convex face is directed upwards and the dry particles captured during the preceding phase are safely protected and the rain drops can flow freely into the container provided to this end at the lower part of the apparatus.

Other advantages and features characterizing this invention will appear as the following description proceeds with reference to the accompanying drawings illustrating diagrammatically by way of example typical embodiments of the fall-out collector according to this invention.

In the drawings:

FIGURE 1 is an axial section illustrating a first form of embodiment of the collector according to this invention;

FIGURE 2 is a part-elevational, part-sectional view showing a precipitation and dew detector;

FIGURE 3 is an axial section similar to FIG. 1 showing a modified embodiment of the apparatus of this invention, and

FIGURE 4 is a wiring diagram of the system for controlling the retractable member.

Referring first to FIG. 1, a fall-out collector according to this invention comprises essentially the component elements of a conventional rain-gauge. In fact, it comprises a shaft 1 having a gauged upper orifice 2, according to meteorological standards. This shaft 1 has a lower funnel-shaped extension 3 provided with a pipe outlet 4 opening into a receiving container 5. The assembly comprising the shaft 1 and funnel 3 is housed in a sealed casing 6 equipped with legs 7 and connected to the top of shaft 1 preferably through a frustoconical portion 9 in order better to bound the passage area through which the fall-out substances are collected by the gauged aperture 2.

The shaft 1 comprises above the funnel 3 a substantially cylindrical portion 10 constituting a housing for a convex member 11 secured on a horizontal spindle 12 extending through said portion 10 and adapted to revolve in its wall. A tray 16 coated internally with a layer of suitable adhesive substance is mounted on the spindle 12 for example by means of bar magnets 17. In the specific form of embodiment illustrated in FIG. 1 the shaft 1 is of cylindrical configuration and the convex member 11 is in the form of a hollow portion of a sphere coaxial with the shaft 1. The diameter of tray 16 is preferably slightly inferior to that of shaft 1, so that in the position shown in the figure any fall-out penetrating through the aperture 2 is collected by this tray. On the other hand the portion 10 of greater diameter should have a cross-section considerably larger than the part-spherical member 11 whereby this member can turn about'the spindle 12 and the precipitated substances can flow freely to the funnel 3 and subsequently into the bottom container 5.

The part-spherical convex member 11 is preferably detachable to permit its replacement upon completion of a measuring period.

A precipitation detector 13 is mounted on the upper end of a tubular support 14 secured on the casing 6 to permit the passage of electrical conductors (not shown) connecting the detector 13 to the convex-member control circuits and mechanisms housed in a weatherproof box 15.

This detector is simply a condenser of practically zero capacity, adapted when coated with a film of water to act as an electric resistance. It comprises a relatively great number of elements imbricated with one another to ensure a high sensitivity. These elements are in the form of printed circuits having their electrically conductive copper portions coated with gold to prevent their oxidation. The remaining surface of each element is coated with cellulose varnish to facilitate the flow of water thereon. The sensitive surface of detector 13 is preferably of frustoconical configuration in order to present a symmetrical form of revolution to atmospheric agents and facilitate the running of Water, and if desired a thermostat (not shown) may be associated with the detector to limit its time constant at the beginning and at the end of the precipitation, the latter being either liquid (rain) or solid (snow, hail, frozen snow-pellets).

According to a modified form of embodiment illustrated in FIG. 2, this detector 13 of substantially frustoconical configuration comprises two groups of different sensitive elements constituting the one a precipitation detector 37 and the other a dew detector 39. Each group consists in turn of two series of alternate elements spaced from each other to an extent corresponding to the desired detection sensitivity; The dew detector constituting the lower portion or larger base of the cone comprises two series of elements 39a, 39b and at the top' the precipitation detector comprises two other series of elements 37a, 3712 more spaced from each other than those of the dew detector, since the precipitation detector should not be responsive to dew but only to heavier precipitation. According to a preferred form of embodiment the intermediate elements 39b and 37b are carried by the same plate which is thus common to both detectors.

Mounted within the cone 13 is a heating resistance 40 having substantially the shape of a tapered spiral coil parallel to the wall of the detector. The detector has its lower portion closed by a bottom plate 42 formed with a central orifice 44 through which an air stream is delivered by a blower (not shown) enclosed in the control box 15. This blower is, connected to the orifice 44 through a pipe 45 surrounded by the tubular support 14 outside the casing 6.

The top of detector 13 has a central aperture 46 protected against precipitation by a conical cap 48, this cap also serving the purpose of deflecting the air heated by the resistance 40' towardthe outer surface of the sensitive elements.

The operation of the air blower and the energization of the electric resistance are controlled through the sensitive, elements of the detector by means of circuit means enclosed in the control box and to be described presently.

To prevent the undesired or untimely turning of the tray 16, and therefore the risk of fall of the collected particles, the tray and convex member assembly may be constructed in the manner illustrated in FIG. 3, wherein the spindle 12 is secured in the wall of shaft 10. A tray 31 coated with adhesive substance and having a diameter at least equal to that of shaft 1 is secured by bar magnets 33 on this spindle 12 and convex member is rotatably mounted about this spindle.

In fact, the spindle 12. carries a hollow member 35' having the shape of a portion of a sphere provided with diametrally opposite bushings 36 fitting rotatably around said spindle 12 on either side of the tray 31. This partspherical member 35 which, in the inoperative position, lies under the tray 31 has a diameter suflicient to cover this tray completely when the spindle 12' has been rotated through a half-revolution from the position shown in the figure.

The circuits and mechanisms controlling this movement of the part-spherical member 35 are enclosed as already stated in a weatherproof box 15 housed in the casing 6. They are connected through conductors running inside the tubular support 14 to the precipitation detector 13.

These circuits may be supplied with electric current either from the mains 50 or from a storage battery 52 (see wiring diagram of FIG. 4) through four mechanically or otherwise interconnected reversing switches 54, 55, 56 and 57 having each their movable contact adapted to engage either of a pair of fixed contacts a, b connected to the mains and to the storage battery terminals, respectively.

One of these reversing switches, namely switch 54, is connected to the elements 39b of the dew detector as Well as to the elements 37b of the precipitation detector, in parallel, and on the one hand to a relay 58, to a transistor 60 associated with the sensitive elements 39a and to reversing switch 55, and on the other hand to a relay 62, to a transistor 64 associated with the elements 37a and to reversing switch 55.

Reversing switch 57 is connected to a relay 68 also to reversing switch 56 through conductors 70, 72 each provided with a switch 74, 76 controlled the one 74 by relay 58 and the other 76 by relay 62. This relay 68 controls two switches 78, 79 for closing the circuits supplying current to the blower 80 and heating resistance 82, respectively.

The reversing switch 57 is further adapted to deliver energizing current to an electromotor 84 for rotatably driving the part-spherical member 11 or 35 and a cam 86 of substantially circular configuration but formed with a notch 88 engageable in the normal inoperative position by a pawl 90 coupled with the movable contact arm 92 of another reversing switch. On the other side of cam 86' another pawl 94 diametrally opposite to pawl 90 is coupled with the movable contact arm 92 of another reversing switch 96.

Reversing switch 36 is adapted to connect the electromotor 84 to reversing switch 56 through the medium of alternatively one or the other fixed contacts a, b of another reversing switch 98 responsive to the aforesaid relay 62. Reversing switch 96 is shunted across the motor 84 and terminal 98a.

Under normal operating conditions, that is, when only dry fall-out substances are to be collected, the collector is in the position illustrated, with the part-spherical member 35 retracted under the tray 31 so that all the dust particles entering the shaft 1 through the aperture 2 are received by this tray. The circuit means controlling this part-spherical member 35 are also in the position shown in FIG. 3.

None of the different relays is energized, switches 74 and 76 are open as well as switches 78 and 79. The movable contact arm of reversing switch 98 engages its fixed contact b, and contact arm 92 engages the fixed contact a associated therewith; thus, switch 96 is closed but the motor 84 is not energized and the part-spherical member 35 and cam 86 are stationary.

Assuming that dew is deposited on detector 13, a contact is created between elements 39a and 3%, whereby current is caused to flow through transistor 60 and relay 58 is energized; Switch 74 closes the circuit to energize relay 68 and the latter closes in turn switches 78, 79 to deliver energizing current to the blower 80 and heating resistance 82. When the combined action of these means has dried out the dew detector, the contact between elements 39a and 39b is discontinued, relay 58 is no more energized and controls the opening of switch 74, thus de-energizing relay 68 and opening switches 78 and 79. The blower 80 is stopped and resistance 82 allowed to cool down.

During this sequence of operations the detector 37 remained inoperative and the part-spherical member 35 was kept under the tray 31.

Assuming now that atmospheric precipitation occurs, for example in the form of rain; the detector 37a, 37b w1ll cause current to be delivered to transistor 64 and to the winding of relay 62, thereby closing switch 76 and moving the arm of switch 38 to engage contact 98a.

The closing of switch 76 energizes relay 68 and closes switches 78 and 79 for energizing the blower 80 and resistance 82 which will both start drying up the detecto 13,

On the other hand, as the movable arm of switch 98 engages contact a while switch 96 is closed and reversing switch 92 is in position 920, the motor 84 is energized and begins to rotate on the one hand the part-spherical member 35 and on the other hand the cam 86. The rotation of this cam 86 in the direction of the arrow (FIG. 4) moves the pawl 90 out from notch 88 and switches the contact arm 92 to contact b. The motor 84 continues to revolve since switch 96 is closed.

When the cam 86 has accomplished a half-revolution, notch 88 registers with and is engaged by the other pawl 94 to open switch 96. Thus, the energization of motor 84 is discontinued and the part-spherical member 35 is also stopped after a 180 degree angular movement, that is, in the position in which it overlies the now inverted tray 31. Thus, rain or any other form of precipitation can run on the outer surface of member 35 and flow down to the funnel 3 and finally into the container 5. The tray 31 is thus safely protected against the risk of receiving precipitation likely to mix up with the previously col lected dry fall-out substances. As long as the precipitation lasts and therefore causes relay 62 to be energized, motor 84 and member 35 remain stationary. When the precipitation ceases and the detector becomes dry, relay 62 is de-energized, switch 76 opens and the contact arm of reversing switch 98 engages its fixed contact I). Relay 68 is also tie-energized, switches 78 and 79 open to deenergize the blower 89 and the heating resistance 82 is also de-energized to allow the detector elements to cool down.

The change of position of switch 98 is attended by another starting of motor 84 energized through reversing switches 57, 92b, 98b and 56. The cam 86 and partspherical member 35 are re-started. The initial movement of cam 86 will disengage the pawl 94 from the cam notch 88 to re-close switch 96, and after a halfrevolution the other pawl 90 drops back into the notch 88 to change the position of reversing switch 92 to 92:1. The energizing circuit of motor 84 is again open and member 35 resumes its inoperative position under tray 31. Then the tray 31 is ready to collect any dry fallout substances passing through the shaft 1 and adhering on its coated surface.

If the rain or other precipitation is so weak as to cause the combined action of the blower and heating resistance to dry the detector 13 before the protection member 35 has completed its half-revolution, that is, when reversing switch 92 is in position 9211 and switch 96 is closed, relay 62 becomes de-energized and reversing switch 98 is moved to position 9812. Under these conditions the electromotor 84 remains energized and the movements of cam 86 and part-spherical member 35 continues. In this position of reversing switches 98 and 92 the opening of switch 96 will not influence the motor operation, whereby the partspherical member 35 will continue its movement until it has completed a full revolution and resumed its initial position. The cam 86 will also make a complete revolution and the engagement of pawl 90 in notch 88 will move switch 92 to the position opening the circuit for energizing the motor 84, and the latter is thus stopped.

Another precipitation occurring during this movement at any time would not interfere with the motor operation which would continue until the part-spherical member 35 has resumed its operative position, the current being supplied through switch 96 and terminal 98a, and being discontinued only by the opening of switch 96.

The action of the dew detector during the operation of the rain detector may be considered as immaterial or negligible since it is substantially coincident with the energization of relay 68.

On the other hand, to prevent the resistance 82 from overheating, a thermostat 100 may be mounted in series therewith.

It is clear that this apparatus will operate in a completely automatic and reliable manner. The protection member 35 is turned to its upper position only when a substantial precipitation takes place, and when the precipitation ceases member 35 resumes its inoperative position immediately, without any risk whatsoever of being stopped in an intermediate position or in a position not consistent with the desired operation.

Moreover, this fall-out collector is free of any handling, keying or the like for its operation, and any supervision is definitely precluded during the fall-out collection periods.

On the other hand, as the tray 31 remains stationary during precipitation and is simply covered by the partspherical member 35, the dry fall-out collected by its adhesive coating cannot become mixed up with the precipitation carried along toward the container 5, and the two types of fall-out substances are definitely separate from each other.

Of course, many modifications and alterations may be brought to the forms of embodiment shown and described herein by way of example, without departing from the spirit and scope of the invention. Thus, notably, the retractable member may have any convex configuration, for example a conical or frustoconical configuration. If desired, a movable member may also be provided protecting the dew detector during precipitation, t complementary member being removed automatbally when the precipitation ceases. Similarly, the de' a d precipitation detectors may be completely indep n each detector controlling a separate heating resistance associated therewith.

On the other hand, the shaft 1 could hayci a sq cross-section, the tray and protection member 31, 35 having in this case a corresponding shape/ Besides, this shaft could have a frustoconical configuration with the small base constituting the inlet opening'll, the tray being disposed just beneath, and having a diameter substantially greater than the major base.

We claim:

1. Atmospheric fall-out collector having a duct having at its upper end a gauged aperture and a funnel of larger diameter than the duct communicating with a precipitation receiving container comprising a surface between the duct and the funnel coated with a layer adapted to retain dry fall-out particles, a retractible member of smaller diameter than and adjacent the mouth of the funnel for protecting said layer against precipitation and for guiding precipitation toward the funnel, a precipitation detector and means for moving said retractible member controlled by said precipitation detector.

2. A collector as described in claim 1 including a spindle, said retractible member being a convex member mounted on said spindle, said spindle supporting said surface.

3. A collector as described in claim 2, said surface revolving with said spindle, said means for moving said retractible member rotating said surface and said retractible member at the beginning and at the end of precipitation.

4. A collector as described in claim 1, said retractible member being a convex member rotatably mounted about said adhesive surface, said surface being fixed in position, said moving means rotating said member at the beginning and at the end of precipitation.

5. A collector as described in claim 1 including means for drying said precipitation detector for holding said retractible member against movement when dew appears.

6. A collector as described in claim 1, said surface consisting of a tray coated internally with an adhesive substance forming said layer and a spindle mounted in the upper portion of said funnel supporting said tray.

7. A collector as described in claim 1, said precipitation detector comprising a frustoconical sensitive surface consisting of two series of imbricated elements and a heating resistance disposed within said sensitive surface.

8. A collector as described in claim 7, said detector including at its lower portion a cold air inlet orifice and of one of said surfaces being sufliciently close to one 5 another to make said one surface sensitive to dew, said elements on the other of said sensitive surfaces being responsive only to heavier precipitation.

10.. A collector as described in claim 7 including a relay controlling said heating resistance, said dew de- 1 tect-or and precipitation detector being connected separately to said relay for controlling said heating resistance and a relay controlling the movement of said retractible member, said precipitation detector only being connected to said relay' for controlling the movement of said re- 15 tractible member. I p v p p 11. A collector as described in claim 1, said'means for moving said retractible member including a motor 8 for controlling the movement of said retractible member, a relay system between said detector and said motor for starting said motor immediately at the beginning and at the end of precipitation and cam means for stopping said motor in the inoperative and operative positions of said retractible member.

References Cited by the Examiner UNITED STATES PATENTS 0 r 2,699,679 1/55 Munger 73-421 X 2,754,460 7/56 Goldman 1 160-5 2,973,642 3/61 Grinnel et al 7328 X 3,104,542 '9/63 "Scoggins 73-170 X LOUISYR. PRINCE, Primary Examiner. RICHARD QUEISSER, Examiner.

Claims (1)

1. ATMOSPHERIC FALL-OUT COLLECTOR HAVING A DUCT HAVING AT ITS UPPER END A GAUGED APERTURE AND A FUNNEL OF LARGER DIAMETER THAN THE DUCT COMMUNICATING WITH A PRECIPITATION RECEIVING CONTAINER COMPRISING A SURFACE BETWEEN THE DUCT AND THE FUNNEL COATED WITH A LAYER ADAPTED TO RETAIN DRY FALL-OUT PARTICLES, A RETRACTIBLE MEMBER OF SMALLER DIAMETER THAN AND ADJACENT THE MOUTH OF THE FUNNEL FOR PROTECTING SAID A LAYER AGAINST PRECIPITATION AND FOR GUIDING PRECIPITATION TOWARD THE FUNNEL, A PRECIPITATION DETECTOR AND MEANS FOR MOVING SAID RETRACTIBLE MEMBER CONTROLLED BY SAID PRECIPITATION DETECTOR.

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