Gas heater

A gas heater for heating a mat 12 soaked with an insecticide or the like, is heated by a catalyst reaction of a combustion gas, e.g. butane comprises a gas container 1, a gas burner 5 surrounded by a catalyst 6 which are contained in a burner 3 with apertures 3a, through which a pilot flame 81 from a pilot nozzle 8 ignited by a high voltage generator 9 is blown; a main valve 41 for the gas burner 5 and a pilot valve 82 for the pilot nozzle 8 and a high voltage generator 9 are controlled in a interlinked fashion.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a gas heater utilizing catalyst 
reaction of a combustion gas, and particularly concerns a portable gas 
heater which can be started safely and easily by a simple operation for 
moderate warming of a heating plate for holding a heating object, such as 
a mat soaked with an insecticide. 
2. Description of the Prior Art 
In recent years, trials are made to react butane or the like combustion gas 
with metal catalyst such as platinum or the like for applying resultant 
heat in heating portable hair curler, portable insence radiator, portable 
insecticide radiator, etc. The above-mentioned portable apparatuses 
utilizing the catalyst reaction of the combustion gas are paid attention 
since wide utilizations and development are expected owing to their 
features that no electric power is used. 
On the other hand, from many years ago, insecticide-mat-heating apparatus 
for evaporating insecticide soaked in a mat by heating a filament heater 
or a semiconductor heater by use of commercial electric power source. 
However, such conventional electric mat heater requires a considerably 
large electric power to raise the heating plate to a certain temperature 
enough to evaporate the insecticide, such as 150.degree. C. Accordingly, 
due to shortage of necessary power to raise the temperature, the 
insecticide mat heating apparatus has not been able to be electrified. 
Besides, a catalyst heater apparatus was recently trial-manufactured. This 
is configurated to use a dry cell as its starting means, wherein an 
electric filament is red-heated to ignite combustion gas. Such 
trial-manufactured apparatus has problems of dry cell replacement, taking 
some time to ignite the combustion gas by red-heating the filament and 
insufficient reliability of starting. Furthermore, since an initial 
ignition of the combustion gas is carried out in a burning chamber which 
is originally designed for the catalyst-reaction, condition for igniting 
is dissatisfactory because of excessive contents of the combustion gas, 
shortage of air, etc. Therefore, such apparatus has, on top of the 
unreliability of the ignition, a liability of making big explosion sound 
at the time of ignition. Such sound is not only uncomfortable for the 
user, but also is undesirable for safety and service life time of the 
apparatus. 
SUMMARY OF THE INVENTION 
Accordingly, in view of the above-mentioned problems of the conventional 
apparatuses, the present invention aims to provide an improved portable 
gas heater, which is suitable for use in heating an insecticide mat, or 
the like and has high reliability in starting of catalyst reaction. 
A gas heater in accordance with the present invention comprises: 
a gas container, 
a main gas nozzle which is provided on the gas container, 
a gas burner which is provided connected to the main gas nozzle and has gas 
outlet apertures, 
a catalyst member disposed outside the gas burner, 
a burner pipe which is provided surrounding the gas burner and the catalyst 
member and has apertures, 
a heating plate provided above the burner pipe as a holding table for 
holding a heating object, 
a pilot nozzle provided outside the burner pipe in a relation to blow a 
pilot gas flame through one of the aperture to the gas burner, for 
starting of burning of gas at the gas burner thereby to start a catalyst 
reaction, and 
ignition means for igniting gas blown from the pilot nozzle to make the 
pilot gas flame. 
The gas heater having the constitution as above-described has a high 
reliability in start of catalyst reaction, safety and comfortableness 
because making no fire, flame or smoke, good efficiency of gas because of 
the catalyst combustion and a convenience of portableness since no 
commercial electric power is required. Furthermore, the starting operation 
of the gas heater can be made with a simple operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Detailed constitution and operation of the preferred embodiment are 
described with reference to the accompanying drawing hereafter. 
On a gas container 1, a casing 2 having an opening 21 for placing a mat 
therein is provided. In the casing 2, a burner pipe 3 having apertures 3a, 
3a for passing air therethrough are fixed on the gas container 1. The 
aperture may be a gap 3a' between the lower end of the burner pipe 3 and 
the upper face of the gas container 1. Further, in the burner pipe 3, a 
main gas nozzle 4 having flanges 42 is provided by connecting its lower 
end to a known main valve 41 of known construction provided in the gas 
container 1. On the upper end of the main gas nozzle 4, a gas burner 5 
having several gas apertures 5a, 5a is provided. On the outer face of the 
gas burner 5, a catalyst 6 is provided to surround the former in a manner 
that the catalyst, such as fine platinum wires are disposed in the 
vicinity of the outer face of the gas burner 5. 
On the upper end of the burner pipe 3, a heating plate 7 which serves as a 
holder for receiving a heating object, such as an insecticide mat 12 put 
in the upper opening 21 of the cases, is provided with an appropriate gap 
space 71 on the upper end of the gas burner 5. Outside and close to the 
burner pipe 3, a pilot nozzle 8 having a pilot nozzle lever 11 is provided 
by connecting its lower end to a pilot valve 82 of known construction 
provided in the gas container 1. The upper end of the pilot nozzle 8 is 
bent toward the gas burner 5 so as to blow a pilot gas flame 81 through 
one of the aperture 3a of the burner pipe 3 onto the gas burner 5. 
Further, in the space of the casing 2, a discharge electrode 9a is 
provided in a close proximity to the outlet end of the pilot nozzle 8. 
And, the discharge electrode 9a is connected to an output terminal of a 
piezoelectric high voltage generator 9. An end tip 9c of an actuating 
member 9b of the piezoelectric high voltage generator 9 pushes up a pilot 
nozzle lever 11 of the pilot nozzle 8. A slide control element 10, which 
is provided slidably on the outer face of the casing 2, has a main lever 
10a which is coupled to the flanges 42 of the main nozzle 4. Furthermore, 
the main lever 10a faces a lower end of the actuating member 9b with a 
specified gap inbetween. The slide control element 10, hence the main 
lever 10a has the following three positions: (1) a resting state shown by 
a solid line designatad by 10 and 10a, which is the lowest position, 
wherein both the main valve 41 and the pilot valve 82 are closed stopping 
flow of the gas, and the piezoelectric high voltage generator 9 as an 
ignition means is off; (2) a starting position shown by two-dot chain line 
designated by 10" and 10a", which is at the opposite end with respect to 
the position of the side control element 10 whereat the main valve 41 has 
been opened and the pilot valve 82 is opened, and a short time thereafter 
an igniting operation of the piezoelectric high voltage generator 9 takes 
place, and (3) a steady state heating position shown by one-dot chain line 
designated by 10' and 10a', which is between the resting position and the 
starting position, whereat the main valve 41 is opened and the pilot valve 
82 is closed, and the ignition means is off. 
Operation of the gas heater configurated as above is as follows. First, the 
slide control element 10 is pushed up from the resting position which is 
at the lowest position to the starting position which is the highest 
position of the control knob 10. As a result of the upward motion of the 
control knob 10, hence the main lever 10a, the main nozzle 4 is pushed up 
and the main valve 41 is opened, and little time thereafter by pushing up 
of the actuating member 9b by the main lever 10a, pilot nozzle 8 is pushed 
up and valve 82 is opened. And finally, as a result of the pushing up 
motion of the actuating member 9b, the piezoelectric high voltage 
generator 9 generates a high voltage pulse, which is impressed on the 
discharge electrode 9a. Therefore, a high voltage sparking takes place 
between the discharge electrode 9a and the outlet end of the pilot nozzle 
8, thereby igniting the gas flow from the pilot nozzle 8 to produce a 
pilot gas flame 81 which blows on the gas burner 5 having the catalyst 6 
thereon. Then, the gas burner 5 is heated by the pilot burner 81, and 
accordingly by the function of the catalyst 6, the gas flowing out from 
the gas apertures 5a reacts with oxygen in the air coming through the 
apertures 3a the burner pipe 3 starting a catalyst reaction. 
Once the catalyst reaction started, the slide control element 10 is placed 
to the middle position, namely the steady state heating position, by means 
of a restoring spring (not shown) included in the generator 9. At this 
middle position, the pilot valve 82 is closed and only the main valve 41 
is opened, whereat the catalyst reaction is stably continued. As a result 
of this catalyst reaction of the combustion gas, the space in the burner 
pipe 3 is moderately heated, and therefore the heating plate 7 fixed 
thereon is heated to a moderate temperature, for instance, 150.degree. C. 
Therefore, a mat soaked with an insecticide, a germicide, an air freshner 
or deodorizer or the like which is put on the heating plate 7 is 
moderately heated and valatilizes the above-mentioned soaked contents. 
When the slide control element 10 is pushed down to its bottom position, 
namely the resting position, both the main valve 41 and the pilot valve 82 
are closed, and thereby the heating is completely stopped. As the 
above-mentioned piezoelectric high voltage generator 9, for instance, 
known apparatus disclosed in the U.S. Pat. No. 3,509,388 or the U.S. Pat. 
No. 4,139,792 is suitable. These arts disclose the piezoelectric high 
voltage generator which generates the high voltage by impressing a 
mechanical motion to piezoelectric element, and are widely used in 
cigarette lighters or gas ovens. Of course, other kinds of high voltage 
igniting means such as high voltage oscillator is similarly usable. 
Since catalyst reaction of the combustion gas is utilized, no smoke or 
flame is produced in the gas heater of the present invention. Accordingly, 
the combustion efficiency is very high. Since there is no flame or smoke, 
the gas heater is usable as a safe portable gas heater in any place. 
Furthermore, there is no need of using the commercial electric power line 
or expensive and heavy dry batteries. Since the heat from the gas burner 5 
is conducted to the heating plate by a rising air flow disposed with a 
predetermined air gap from the gas burner 5, the surface of the heating 
plate 7 is moderately heated, and therefore, there is no fear of 
accidental burning through excessive heating of the mat 12 put thereon. 
Since a combustion gas contained in the gas container 1 is used as the 
energy source, the gas heater can be used for very long time. Or in other 
words, the volume of the gas container can be very small for ordinary use 
for the insecticide, the germicide, the room freshner or deodorizer. This 
gas heater makes no blasting sound at the starting, since the catalyst 
reaction is started by heating the gas burner 5 by means of a pilot flame 
81 having sufficient heat from the pilot nozzle 8. Therefore, the 
apparatus is safe and reliable. The safe ignition is further assured by 
the use of the high voltage ignition means 9 and 9a.