Insecticidal Fumigator

Abstract

In an insecticidal fumigator, liquefied gas available in the form of cigarette lighter fuel is ignited through an electric circuit including a radiating filament connected to a dry cell and a normally open pushbutton switch, and once ignited, it is kept catalytically burnt to heat a heating plate so that an insecticide imbued in a fibrous tissue element adjacent to said plate is smoked into the air. Said fumigator is provided with a safety device comprising a bimetallic actuator adapted to automatically close a valve when overheating takes place whereby a fuel supply pipe connected to said valve is prevented from feeding the fuel.

Description

The present invention relates to improvements in an insecticidal fumigator, and more particularly to an improved type insectifuge smoking means provided with a particular safety device and adapted to be heated for fumigation by liquefied gas.

In order to exterminate humming mosquitoes, flies and any other insects noxious to men and beasts, it has been customary to smoke an insecticidal component effective to stamp out these insects so as to vaporize the component into the air thereby subjecting the insects to the fumes of the component.

For that purpose, use is made for example of a type of fumigator that comprises a heating coil or nichrome wire which serves as a heating source, a heating plate to which the calorific volume of the coil when heated is conducted, and in use a paste of insecticide or a fibrous tissue board impregnated with an insecticidal component is mounted on the heating plate so as to be smoked to vaporize the fumes of the component by the heat conducted to the heating plate from the heating coil.

However, the aforesaid type of fumigator has fatal defects in that no one can use it without taking the trouble of looking for a source of electricity accessible to him whenever necessary and therefore, in order that he can use it freely in any selected position, he must previously provide such positions with the corresponding number of sources of electricity.

With the view of eliminating or mitigating the above-mentioned drawbacks of conventional fumigators, there are available some improved different types of fumigator which are adapted to use dry cells as a source of electric power so as to heat nichrome wire provided therein. With these fumigators, however, the electric power to be consumed by the nichrome wire is so great that if the wire is kept continuously charged with electricity, it will consume the accumulated electricity of the dry cells in a short length of time, the result being that a user must very often exchange the cells at his extra purchasing expense.

Furthermore, the aforesaid type of fumigator has an additional drawback in that as long as the nichrome wire is left electrified, it will continue to be heated wastefully even after the insecticidal component has completely escaped in vapor form from a fibrous tissue board so that if a user, while using the fumigator in bed, should fall asleep forgetting to switch off the electric circuit thereof, the heating plate of the fumigator is easily overheated in his sleep, often giving rise to a burn or fire.

In order to eliminate the above-mentioned drawbacks, the present invention has been designed wherein suitable liquefied gas is employed as fuel so as to take advantage of the peculiar properties of the gas that, when contained in a fuel storage tank, it can be compressed liquescently to the minimum of volume but in use it can be inflated gaseously to the maximum of volume.

More particularly, the insecticidal fumigator in accordance with the present invention is adapted to inflatably eject the liquefied gas from a fuel storage tank to a radiating means in which there is disposed a pinch of asbestos, glass wool or any other similar fire-proof fibrous tissues containing a catalyst composed of platinum, palladium or a mixture thereof so that the ejected gas is continuously oxidized in the presence of the catalyst to provide a smokeless and scentless heat-source.

In this fumigator the fuel storage tank and a fuel supply pipe which connects the tank to the radiating means are covered with a heat-resisting, adiabatic material whereby the heat generated in the radiating means is not conducted to both the pipe and the tank which otherwise might be easily overheated to be damaged.

Furthermore, the fumigator of the invention is so designed that the supply of the liquefied gas is automatically stopped when the radiating means is overheated.

Accordingly, the present invention has as one of its main objects the provision of a novel and improved insecticidal fumigator which can eliminate all the drawbacks of the conventional fumigators;

It is another object of the invention to provide a fumigator in which liquefied gas is utilized as the fuel for providing a heat-source.

It is a further object of the invention to provide a novel and improved insecticidal fumigator provided with a safety device which is adapted to automatically the stop supply of liquefied gas when the radiating means is overheated, thereby preventing the risk of a burn suffering and fire occurence.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing wherein like reference numerals designate like parts in the several figures.

FIG. 1 is a perspective view showing a preferred embodiment of the insecticidal fumigator in accordance with the invention;

FIG. 2 is a diagrammatic view showing the interior portions of FIG. 1 partially in section;

FIG. 3 is a perspective view showing a fibrous tissue board impregnated with an insecticidal component to be used in the embodiment of FIG. 1; and

FIG. 4 is a diagrammatic view partially in section showing the interior portions of a modification of the invention.

Referring now to the drawing, and in particular to FIG. 1 and 2, the insecticidal fumigator A of the present invention comprises a housing 10, a fuel storage tank 11, a fuel supply means 20, a safety means 30, an ignition means 40 and a radiating means 50 being all housed in said housing 10. Said housing 10 is formed into any desired shape with a suitable heat-resisting and adiabatic material.

Said fuel storage tank 11 comprises a metallic layer 12 and a heat-resisting, adiabatic coating 13 composed for example of fluorine resin or silicone resin material whereby even if the fumigator A is super-heated by the over-ejection of the liquefied gas that might take place due to a mishap to a valve means provided for regulating supply of the gas or for any other reasons, the heat of the fumigator A is completely prevented from being conducted to the fuel storage tank 11.

Inasmuch as it has been empirically proved that a fluorine resin is heat-proof up to 350.degree. C and a silicone resin to a little more or less than 1,500.degree.C, said heat-resisting, adiabatic coating 13 is not altogether used to cover the whole outer surface of the metallic layer 12 but is used to cover some elemental portions thereof which are directly in abutment with the wall of the housing 10 to be collectively heated to an excessive degree of temperature.

The fuel storage tank 11 is further provided with a gasified fuel inlet 14 and a passageway 15 for connecting subsequently described fuel supply pipes. The opening of said inlet 14 is exposed externally of the tank 11 and formed to make such a shape that liquefied gas containers available on the market can be applied to the opening so that a user can easily fill the tank 11 with liquefied gas such as butane (C.sub.4 H.sub.6) which is available in the form of a compressed gas fuel container for cigarette gas lighters.

The fuel supply means 20 comprises a pair of fuel supply pipes 21, 22 and a valve 23 mounted between these pipes so as to regulate supply of the gas fuel. Said pipe 21 is preferably composed of a heat-resisting, adiabatic fluorine or silicone resin so as to prevent the heat of the fumigator from being conducted to the tank 11. Contrary thereto, said pipe 22 is preferably made of a metal so as to be fixedly held in the radiating means 50.

Said regulation valve 23 may be of any type producible in the art well known in the field of general cigarette gas lighters and serviceable to regulate the flow of liquefied gas ejected from the fuel storage tank 11.

The safety means 30 is provided with a bimetallic actuator 31 which is formed to be curved in one direction when it is heated to a fixed degree of temperature so that if the radiating means 50 is overheated due to the overflow of the liquefied gas and the temperature of the fumigator A is raised to a dangerous degree, then the bimetallic actuator 31 will be bent in one direction to actuate the regulation valve 23 through an actuating means 24 operably connected to the bimetallic actuator 31 thereby closing the valve 23 to stop the further flow of the liquefied gas 16, resulting in the radiating operation of the radiating means 50 being automatically brought to a halt.

Said safety means 30 is disposed in a suitable position within the housing 10 and the bimetallic actuator 31 is disposed in a manner of being bent in a selective direction subject to the type of a regulation valve 23 applied to the fumigator A and the configuration of an actuating means 24 connected to the bimetallic actuator 31.

Incidentally, said regulation valve 23 is so adapted that once closed by the action of the bimetallic actuator 31, it will remain closed as it is until a user purposedly opens it thereby preventing the further flow of the liquefied gas 16 into the radiating means 50. In place of said regulating valve 23, there may be used a thermostatic valve 23a in the form of the regulation valve 23 and a bimetallic actuator 31 combined therewith so as to prevent the flow of the liquefied gas 16 into the radiating means 50.

The ignition means 40 comprises at least a single dry cell 41, contact elements 42, 43, connection cords 44, 45, igniting filament 46 and a switch 47. Said contact elements 42, 43 are made of resilient metal and adapted to detachably hold the dry cell 41 therebetween in electro-conductible contact with the positive and negative poles thereof so that the dry cell 41, when used up, can be easily exchanged for a new one.

The switch 47 employed in the present embodiment is a normally open type switch having a push button so provided that when pushed it permits electricity to flow through the connection cords 44, 45 thereby red-heating the filament 46 and that when released it serves to stop the flow of electricity thereby keeping the igniting filament 46 from being heated.

However, it is also possible to mount said ignition means 50 cooperatively with the safety means 30 and the regulation valve 23 in order that when the fumigator A of the present invention happens to be superheated, the bimetallic actuator 31 of the safety means 30 is automatically bent in one direction to actuate the actuating element 24 thereby stopping supply of the liquefied gas 16 into the radiating means 50 but when the superheating of the fumigator A is terminated, the regulation valve 23 is automatically opened to resume supply of the gas 16 into the radiating means 50 thereby actuating the ignition means 40 to red heat the filament 46 and ignite the gas 16 supplied to the radiating means 50.

In the radiating means 50 of the present embodiment, a pinch of asbestos, glass wool or any other suitable carrier 51 including a combustion accelerating catalyst such as platinum, palladium or a mixture thereof is disposed adjacent to the opening of the metallic pipe 22 and protected with a suitable heat-proof mesh netting cover 52 so as to prevent the scattering and losing of the carrier 51. On the outer surface of said cover 51 is placed a metallic plate 53 for receiving an insecticidal fibrous board 54.

Referring to the practical use of the fumigator A in the present embodiment, the regulation valve 23 is opened to supply the gas 16 to the radiating means 50 through the metallic pipe 22, while, the push button 47a of the normally open type switch 47 is pushed to electrify the igniting filament 46 until it is heated red to ignite the gas 16 supplied into the radiating means 50.

As long as the valve 23 is opened, the gas 16 inflatably atomized through the valve 23 is continuously ejected toward the carrier 22 to be oxidized in the presence of the catalyst. Incidentally, if platinum is used as the catalyst for example in the above-mentioned case, then it will be able to utilize substantially 56 times greater quantity of oxygen from the air at the temperature of 400.degree.C than when it is not used at the same temperature so that the ejected gas 16 is momentarily oxidized in the presence of platinum to radiate the calorific volume of 687 Kcal per gram molecule of butane. The chemical reaction which takes place is: C.sub.4 H.sub.10 +130 400.degree. C 4CO.sub.2 +5H.sub.2 O+687Kcal

Accordingly, the heat thus radiated is directly conducted to the metallic plate 53 to fumigate a subsequently described insectidal fibrous tissue board 54.

As is clearly evident in FIG. 3, the board 54 is made of suitable fibrous tissue material impregnated with a pesticidal component and substantially the same shape as the metallic plate 53 upon which it is to be placed for the purpose of fumigation. Preferably the board 54 is previously dyed in such a color that becomes faded when the component imbued in the board has been completely vaporized in the air so that a user can visually ascertain whether or not the board is still effective to kill insects when it is further heated.

Referring to the drawing, and in particular to FIG. 4 in which the second embodiment is illustrative of the fundamentally same principle as the preceding embodiment of the invention, a roll of longitudinal tape 63 is employed in place of said fibrous tissue board 54, which tape 63 is made of fibrous tissue material impregnated with an insecticide and rolled on a cylindrical core 62 so that the tape 63 can be fed over the radiating means 50 according to the arrow P shown in FIG. 4. The core 62 is rotatably inserted onto a shaft 61 axially held between a pair of supporting members 60 to be described hereinafter whereby the fumigator A' is able to effect a fumigating operation for more continuous hours than in the preceding embodiment. Said pair of supporting members 60 are preferably made of suitable resilient material so that the shaft 61 for supporting the roll 63 can be rotatably and detachably held between the supporting members 61 without the necessity of using a screw driver or any other tools.

Over the radiating means 50 there are provided at least a pair of guide rolls 64, 65 for guiding the longitudinal tape 63. At the side of the fumigator A' opposite to the supporting means 61 there is provided a drive means generally designed by the mumeral 66. In order to minimize the cost of manufacture and maintenance, said drive means 66 is preferably of a clockwork system using a coil spring 68 for a driving source, which means includes a handle 67 for manually winding up the coil spring 68 in the clockwise direction Q and a pair of opposed rolls 69, 70 to be driven by the dynamical stability of the wound coil spring 68.

In case of putting the above-mentioned second embodiment in practical use, the coil spring 68 is wound up by turning the handle 67 so as to transmit the dynamical stability of the coil spring 68 to said pair of rolls 69, 70 through a gear mechanism (not shown). On the other hand, the end of the longitudinal tape 63 is rolled out to pass between the rolls 69, 70 through the guide rolls 64,65. Then the rolls 69, 70 are relatively moved in the directions of the arrows by said dynamical stability to frictionally move the tape 63 in the direction where the rolls are moved. Incidentally, it is to be noted that the speed at which the longitudinal tape 63 is moved must be previously determined subject to the rate of speed at which the insecticidal component impregnated in the tape 63 can be fumigated. For this purpose, it is preferable to properly adjust the rotational speed of the rolls 69,70 by means of a suitable reduction mechanism.

Further it is also to be noted that the distance between the radiating means 50 and the tape portion 63 passing thereover is always fixed in a manner such that the tape portion 63 can be heated up to a temperature of approximately 60.degree.C at which the fumigating purpose can be most effectively accomplished. In addition, if the longitudinal tape 63 is previously dyed in a color which fades when the component impregnated in the tape 63 has been vaporized in the air, then it is possible to advantageously determine the most suitable rotatory speed of the rolls 69,70 merely by seeing the degree to which the colored tape 63 has faded.

Incidentally, the housing 10 has apertures 10a through which the fumes of the insecticidal component imbued in the longitudinal tape 63 are dissipated into the air.

Reference numeral 55 denotes a stand for supporting the radiating means 50.

While, in the second embodiment, the thermostatic valve 23a is used which comprises the regulation valve 23 incorporated with the bimetallic actuator 31, the function thereof is the same as that which has referred to in the first embodiment. The fuel storage tank (11), the ignition means 40 and the radiating means 50 in the second embodiment are the same as those respectively corresponding thereto in the first embodiment.

In place of the igniting filament 46 connected to the dry cell 41 in the manner described and illustrated in the foregoing, a flint-type ignition system or a piezo-electric ignition system that is known in the cigarette lighter field may be employed. It will be easily understood that the ignition purpose can be attained by means of a safety match when a dry cell is exhausted and no substitute dry cell is accessible to a user.

It should be noted that the present invention illustrated and described in the drawing and foregoing description, is to be considered as illustrative and non-restrictive in character, and that all changes and modifications that come within the spirit and scope of the invention are included.

Claims

I claim:

1. An insecticidal fumigator, comprising:

a housing;

fuel storage tank means in said housing having an inlet for injecting liquefied gas fuel therethrough and an opening for ejecting gaseously said fuel therefrom;

heat radiating means in said housing including a combustion accelerating catalyst, a carrier thereof and a protecting cover means for preventing the scattering and losing of said carrier;

fuel supply means for supplying fuel from said fuel storage tank to said radiating means;

valve means connected to said fuel supply means including a valve adjustable to open and close, thereby controlling the supply of said fuel;

safety means in said housing for automatically closing the valve of said valve means upon the presence of excessive heat; and

accommodating means in said housing for accommodating an insecticide carrying means adjacent said heat radiating means.

2. The insecticidal fumigator in accordance with claim 11 further including ignition means in said housing for igniting said fuel.

3. The insecticidal fumigator, as set forth in claim 12, wherein said ignition means comprises a dry cell, a pair of electric wires, and an igniting filament disposed within said radiating means to be electrically heated red through said electric wires.

4. The insecticidal fumigator, as set forth in claim 1, wherein

said fuel storage tank means comprises a metallic layer and a heat-resisting adiabatic coating which covers said layer.

5. The insecticidal fumigator, as set forth in claim 1, wherein

platinum is used as said catalyst.

6. The insecticidal fumigator, as set forth in claim 1, wherein

palladium is used as said catalyst.

7. The insecticidal fumigator, as set forth in claim 1, wherein

asbestos is used as said carrier.

8. The insecticidal fumigator, as set forth in claim 1, wherein,

glass wool is used as said carrier.

9. The insecticidal fumigator, as set forth in claim 1, which includes,

a metallic heating plate provided above said radiating means.

10. The insecticidal fumigator, as set forth in claim 11, wherein said accommodating means includes, a pair of supporting members for rotatably supporting a roll of longitudinal tape impregnated with an insecticidal component,

a pair of guide rolls provided above said radiating means, and

a drive means having at least a pair of rolls for moving said tape across said guide rolls.

11. The insecticidal fumigator, as set forth in claim 10, wherein,

said drive means comprises a clockwork system to transmit the dynamical stability of a coil spring to said rolls through a gear mechanism.

12. The insecticidal fumigator in accordance with claim 11 wherein said safety means includes a bimetallic actuator means cooperating with said valve means.