An inhalator comprises a water level adjusting chamber which fluidly communicates a water supply chamber and a vaporizing chamber. A manually operable valve interrupts communication between the level adjusting and vaporizing chambers. Upon closing of the valve, a power supply circuit is turned on to energize a heater for heating water in the vaporizing chamber. The interruption of communication between the level adjusting and vaporizing chambers during the use is effective to obtain only a relatively small amount of water to be heated.

BACKGROUND ART 
This invention relates to inhalators in which water in a vaporizing chamber 
is boiled by a heater to generate vapor and, more specifically, 
improvements in the inhalators the ejection of generated vapor of which 
causes a medicinal liquid or the like inhalant contained in a suction tank 
sucked up and atomized for inhalation into patient's mouth to lessen his 
throat pain and the like. 
Although not used as the inhalator, there has been suggested a steamer for 
generating vapor using a heater in U.S. Pat. No. 3,742,629 of E. R. Plasko 
dated July 3, 1973 or Japanese Patent Publication No. JP, B, 5342/1979 of 
S. Takakuwa et al dated Mar. 15, 1979. In the steamer of the former 
patent, a vapor tank of truncated conical shape is made relatively small, 
a nozzle is secured as extending obliquely upward at the head portion of 
the tank and a heater assembly is vertically erected within the tank. This 
steamer, however, has a problem that, because the tank is made small, 
water in the tank can be soon used up and thus the user must frequently 
supplement water into the tank every time of use. In addition, since the 
water supplementation is performed usually manually and it is difficult to 
maintain always constant the amount of supplemented water, the time 
required for vapor generation determined by the supplemented water amount 
is made variable and the time of continuous use available for each water 
supplementation is also made variable, so that there have been various 
difficulties in its practical applications. 
On the other hand, in the steamer of the latter publication, a vaporizing 
chamber having a heater secured thereto and a water reservoir chamber are 
provided. The top end portion of a water pipe is coupled through a valve 
means to the water reservoir chamber. The pipe extends between the 
vaporizing and reservoir chambers and is projected downward into the 
vaporizing chamber. The water pipe is provided at its downward tip end 
with a small hole and at the circumference above the tip end with water 
outflow holes so as to determine the level of water supplied into the 
vaporizing chamber. This arrangement is advantageous in that the water 
level in the vaporizing chamber is determined by the water outflow holes 
of the water pipe and thus the time necessary for vapor generation is made 
constant, and that water can be continuously supplied from the water 
reservoir to the vaporizing chamber and thus the continuous operation time 
can be prolonged sufficiently, removing various problems occurred in the 
above U.S. Patent. However, this arrangement is still defective in that 
when the water level within the vaporizing chamber temporarily drops below 
the outflow holes of the water pipe, the amount of ejected vapor is 
decreased, i.e., the vapor ejection pressure is not constant but is rather 
varied. Therefore, this arrangement is completely unsuitable for use as 
the inhalator which utilizes the vapor ejection pressure to suck and 
atomize the inhalant from a suction tank by the Venturi effect. 
In the arrangement of Japanese Patent Publication, further, the small hole 
provided in the tip end of the water pipe is open in the vaporizing 
chamber, so that the heated water may be subject to inherent convection 
through this hole, making impossible to realize a rapid vapor generation. 
In this connection, if the small hole is selected to have such a diameter 
that can prevent the convection, then the small hole is clogged by fur and 
the like and its function of adjusting the supplied water level is 
disadvantageously lost. 
TECHNICAL FIELD 
A primary object of the present invention is, therefore, to provide an 
inhalator for the ejection of generated vapor of boiled water in a 
vaporizing chamber to suck and atomize the inhalant from a suction tank, 
which enables a continuous supply of a fixedly small amount of water for a 
long time, achievement of rapid vapor generation and retention of 
substantially constant vapor ejection, to assure the satisfactory Venturi 
effect. 
This object of the present invention is attained specifically by arranging 
the inhalator to have a water level adjusting chamber between the 
vaporizing chamber and a water supply chamber containing a detachable 
water supply tank for keeping a constant water level in the vaporizing 
chamber, and a valve means between the vaporizing chamber and the water 
level adjusting chamber for interrupting communication between them upon 
use of the inhalator. With this arrangement, the supplied water level in 
the vaporizing chamber is kept at a level determined by the water level 
adjusting chamber and, when the inhalator is used, the communication 
between the vaporizing and adjusting chambers is interrupted, preventing 
the occurrence of convection during heating of water, whereby the above 
object can be effectively realized. 
Other objects and advantages of the present invention shall become clear 
from the following description of the invention detailed with reference to 
an embodiment illustrated in accompanying drawings.

While the present invention shall now be described with reference to a 
preferred embodiment shown in the drawings, it should be understood that 
the intention is not to limit the invention only to the particular 
embodiment shown but rather to cover all alterations, modifications and 
equivalent arrangements possible within the scope of appended claims. 
DISCLOSURE OF THE INVENTION 
Referring to FIGS. 1 and 2, there is shown an inhalator according to the 
present invention which generally comprises a housing 10, a suction tank 
11 containing an inhalant liquid such as a salt solution and the like, and 
a skirt 12 projected out of the front part of the housing 10 and carrying 
the suction tank 11, and a cover 14 having an ejected vapor outlet 13 
forwardly and substantially horizontally extended and covering the upper 
side of the housing. The housing 10 and cover 14 together define a casing. 
In this case, it is preferable that the housing 10, suction tank 11 and 
cover 14 are all made of a heat resistant synthetic resin. Within the 
housing 10, a vaporizing chamber 16 is provided behind a front wall 15 of 
the housing 10, and a water supply chamber 19 detachably accommodating 
therein a water supply tank 18 is provided in the vicinity of a back wall 
17 of the housing. The water supply tank 18 is preferably made of a 
heat-resistant transparent synthetic resin such as polycarbonate. In the 
illustrated embodiment, the water supply chamber 19 is positioned at a 
level higher than the vaporizing chamber 16, and a water level adjusting 
chamber 20 which functions to maintain the level of water in the chamber 
16 constant is disposed between the vaporizing and water supply chambers 
16 and 19. In addition, a vertically movable valve member 22 made 
desirably of a heat resistant synthetic resin is disposed vertically above 
an upwardly opened communication path 21 between the vaporizing chamber 16 
and the water level adjusting chamber 20 so that lower end portion 23 of 
the valve member 22 normally biased upward can engage in the path 21 to 
close it. A heater means 24 is disposed in the bottom part of the 
vaporizing chamber 16. 
Referring more in detail to the arrangement of the respective parts of the 
above inhalator, the water supply chamber 19 is formed to have at its 
bottom a water supply port 25, and a water supply valve 28 is movably 
provided in this water supply port 25 so as to normally close the port 25 
as so biased by means of a spring 27. The water supply tank 18 has, on the 
other hand, at the top port of its bottle shape a cap 26 removably mounted 
to the port through a sealing O-ring 31 and carrying a valve 30 movably 
provided in a central opening of the cap 26 so as to normally close the 
opening as so biased by a spring 29. When the user places the water supply 
tank 18 filled with water into the water supply chamber 19, turning the 
tank upside down, to have the cap 26 seated on the bottom of the chamber 
19 in alignment with the port 25, a projected rod of the valve 28 abuts 
against a projected rod of the valve 30 of the tank 18, compressing the 
respective springs 27 and 29 to each other, whereby the both valves 28 and 
30 are caused to shift into their position of opening the water supply 
port 25 and the port of the tank 18, so as to supply water of the tank 18 
into the water level adjusting chamber 20. In this case, a sealing O-ring 
32 fitted around the tank 18 adjacent the top port resiliently engages 
with the inner peripheral wall of the chamber 19 to achieve a water-tight 
sealing around the water supply port 25. 
In the illustrated embodiment, the water level adjusting chamber 20 is 
arranged to have a two-stage stepped bottom and its upper stage surface 
acts as a stopper for the downward shift of the valve 28 to keep the valve 
30 of the tank 18 in its opening position. The water level adjusting 
chamber 20 communicates with the vaporizing chamber 16 through the 
communication port 21 opened upward in the lower stage bottom part as 
defined by opposing inner wall portions 33 and 34 of the housing 10. The 
valve member 22 is of a vertically elongated rod shape, the lower end 
portion 23 of which having a sealing O-ring 35 fitted therearound can be 
sealingly inserted into the communication path 21 when depressed downward 
against the upward biasing force to interrupt the communication. The valve 
member 22 thus comprises an elongated valve rod 36 having the lower end 
portion 23 and a push-button 38 integrally secured to the other top end of 
the rod for upward projection out of an opening 37 of the cover 14. This 
valve rod 36 extends through a vapor-release vent 39 of the chamber 16 
opened above the communication path 21, and a closure flange 40 provided 
at an intermediate position of the rod 36 is sealingly engaged into the 
vent 39 upon the downward depression, so that a sealing O-ring 41 fitted 
to the outer periphery of the flange 40 will fluid-tightly engage with the 
upper end of the inner wall portion 33 and opposing end portion of upper 
wall portion 42 of the chamber 16 which are defining the vent 39. As a 
result, when the valve rod 36 is shifted downward with the push button 38 
depressed, the communication path 21 and vapor release vent 39 are both 
closed concurrently. 
The valve rod 36 is slidably guided by a lip portion 44 projecting upwardly 
from the periphery of an opening of a horizontally extending upper wall 43 
of the housing 10 and also by the peripheral edge of another opening of an 
inner wall portion 45 horizontally extended from the front side wall of 
the water supply chamber 19 in the housing 10. In the illustrated 
embodiment, a sealing O-ring 46 is fitted to the peripheral edge of the 
opening in the inner wall portion 45. A sealing plate 47 having an opening 
through which the valve rod 36 is slidably passed is disposed above the 
O-ring 46, and a return coil spring 48 is fitted around the rod 36 between 
the sealing plate 47 and an upper flange having a rearwardly extended 
actuating arm 49 of the rod 36 at a position just below the lip portion 44 
of the housing 10, so that the rod 36 is normally biased into its upper 
position of FIG. 2, while the plate 47 is biased always against the O-ring 
46 to sufficiently achieve fluid-tight sealing at the opening of the inner 
wall portion 45. A microswitch 50 is mounted to the front side wall of the 
water supply chamber 19 to be actuated by the arm 49 of the valve rod 36 
upon its downward movement so that the microswitch 50 electrically 
connected to a circuit for energizing the heater means 24 will cause an 
electric current to be fed to the heater means 24 as a result of the 
depression of the push button 38. 
A vapor release space 51 is defined by the inner wall portion 42 having the 
vapor release vent 39 and the inner wall portion 45 extending above the 
vent 39 from the water supply chamber 19, and this space 51 communicates 
on its rear side with a vent passage 52 defined between the inner wall 
portion 33 of the vaporizing chamber 16 and the front wall portion of the 
water supply chamber 19, and on the front side with a vapor release duct 
53 disposed above the vapor chamberizing 16 and opened at the front wall 
15 of the housing 10. The duct 53 is preferably made of a heat-resistant 
synthetic resin. With this arrangement and at the upper position of the 
valve rod 36 as in FIG. 2, vapor present within the vaporizing chamber 16 
can be discharged out of the housing 10 through the vapor release space 51 
and duct 53 because the closure flange 40 is released from the vapor 
release vent 39. On the other hand, the water level adjusting chamber 20 
is always subjected to the atmospheric pressure imparted through the duct 
53, space 51 and vent passage 52. In addition, the vaporizing chamber 16 
is provided at its top wall with a vapor outlet passage 54 of a tubular 
shape projected out of the top wall, and the passage 54 is coupled at 
projected end to a lower end of a vapor ejecting pipe 55 which is L-shaped 
and extended at the other upper end horizontally forwardly. The pipe 55 is 
desirably made of stainless steel or a heat-resistant synthetic resin and 
is provided at its upper end with an ejecting nozzle 56. The other inner 
end of the vapor outlet passage 54 is extruded into an outflow channel 59 
defined by blocking plates 57 and 58 for preventing any condensed vapor 
droplet from entering directly into the passage 54. 
Referring also to FIG. 4, the heater means 24 disposed at the bottom of the 
vaporizing chamber 16 comprises a heat radiating plate 60 secured to the 
lower end portions of inner walls of the vaporizing chamber 16 by screws 
or other proper securing means. In the present instance, the heat 
radiating plate 60 is preferably made of a zinc or aluminum die cast 
having a wavy shape in section including continuous two substantially 
inverted U-shaped portions slightly widened outward, inside the top of 
each of which portions a spacer 61 is provided, and an electrically 
insulating sheet 62 is provided against inner surfaces of the respective 
inverted U-shaped portions and of the spacers 61. The inverted U-shaped 
portions contain respectively a plate-shaped heat generating element 63 
erected in width direction in the present instance to extend from the 
bottom of the inverted U-shaped portion to the lower surface of the spacer 
61, as held between a pair of electrode plates 64 which are tapered toward 
the top of the inverted U-shaped portion to substantially fully conform to 
the inner side surfaces of the latter. The element 63 is made preferably 
of a thermistor having a positive characteristic. The electrode plates 64 
are made of brass and the electrically insulating sheet 62 is made of a 
highly heat conductive silicon rubber, preferably. In the illustrated 
arrangement, the electrode plates 64 holding each of the heat generating 
elements 63 are thus electrically insulated by the sheet 62 from water 
inside the chamber 16. 
A push-plate 65 is provided on the bottom end portions of the thus 
assembled heat generating elements 63 and electrode plates 64, and a 
bent-plate spring 66 is placed beneath the push-plate 65 for urging the 
assembled members 63 and 64 into the fully engaging position with the 
surrounding members 60-62, as carried by a support plate 69 secured by 
push nuts 68 to holding projections 67 formed integral with the heat 
radiating plate 60 and extended downward. That is, the push-plates 65 are 
pushed up by the spring 66 so that the electrode plates 64 come into tight 
contact with the heating element 63 by a wedge action occurring between 
the tapered outer surfaces of the electrode plates 64 and the inner side 
surfaces of the insulating sheet 62 within the inverted U-shaped portions 
of the wavy plate 60. The electrode plates 64 are connected through 
leading terminals 70 (only one of which is shown in FIG. 4) to a power 
supply cord 71 including the microswitch 50 and further through a plug 72 
to a commerical power source. 
The suction tank 11 mounted on the skirt portion 12 is divided into an 
inhalant chamber 73 on its rear side and a reservoir chamber 74 on its 
front side, and the reservoir chamber 74 is opened at its top to 
accommodate a lower wall end of the vapor outlet 13 positioned above the 
chamber 74. Disposed above also opened top of the inhalant chamber 73 is a 
suction nozzle 75 formed integral with the vapor nozzle 56 at right angled 
relation thereto, so as to perform the Venturi action when vapor is jetted 
from the nozzle 56, for which purpose the suction nozzle 75 is coupled to 
a suction tube 76 reaching nearly to the bottom of the inhalant chamber 
73, the tube being also made preferably of a silicon rubber. 
The operation of the inhalator according to the present invention shall be 
explained next. With the state shown in FIG. 1 of the device, the user 
removes the cover 14 and inserts the water-filled tank 18 into the water 
supply chamber 19 turning the tank upside down to seat the cap 26 on the 
bottom of the chamber 19 and thus to open the both valves 28 and 30. Then, 
water is supplied from the water supply tank 18 to the water level 
adjusting chamber 20 communicating with the water supply chamber 19 until 
air flowing into the water supply tank 18 through the duct 53, space 51 
and vent passage 52 stops, that is, until the water level in the adjusting 
chamber 52 reaches the lower edge of the water supply port 25. Since the 
water level adjusting chamber 20 is positioned next to and substantially 
at the same level as the vaporizing chamber 16, it will be appreciated 
that water is also supplied into the chamber 16 to the same level as the 
chamber 20 communicating with each other, and this level is kept always 
constant so long as the communication between the chambers 16 and 20 is 
maintained. 
Under this condition, when the user depresses the push button 38 with his 
finger from the position of FIG. 2 to shift the valve rod 36 to its lower 
position of FIG. 3, the lower end portion 23 of the valve rod is engaged 
into the communication path 21 in the liquid-tight relation thereto so 
that the communication between the water level adjusting chamber 20 and 
the vaporizing chamber 16 is interrupted. As the same time, the 
microswitch 50 is actuated by the actuating arm 49 of the rod 36 and the 
power supply circuit is turned on so that, with the plug 72 of the cord 71 
connected to the commercial power source, the electric current is supplied 
to the heater means 24, the supplied current to the electrode plates 64 of 
the heater means 24 causes heat generated by the elements 63 to heat the 
plate 60, whereby water of the predetermined amount for the heat radiating 
plate 60 is boiled to fill the vaporizing chamber 16 with generated vapor, 
which is passed through the channel 59, outlet passage 54 and ejection 
pipe 55 to the nozzle 56 to be ejected thereout. The ejected vapor causes 
the Venturi action with respect to the suction nozzle 75 so that the salt 
solution or the like inhalant contained in the inhalant chamber 73 is 
sucked through the suction pipe 76 out of the suction nozzle 75 to be 
atomized with the ejected vapor from the nozzle 56 and discharged from the 
atomized vapor outlet 13 of the cover 14 into, for example, the user's 
mouth. 
During the foregoing operation, as the amount of water supplied to the 
heater means 24 in the vaporizing chamber 16 is always kept substantially 
constant and the heat radiating plate 60 has the two continuous inverted 
U-shaped portions providing an increased surface area, the heat radiating 
plate 60 can have an effectively widened heating area for the 
predetermined amount of water, whereby required time for generating vapor 
after the operation of the push button 38 can be substantially always kept 
constant as effectively shortened. In other words, since it is required to 
boil only a relatively small amount of water which has been supplied in 
the vaporizing chamber 16, the vapor generating efficiency can be 
remarkably improved. As the communication between the vaporizing chamber 
16 and the water level adjusting chamber 16 is interrupted by the closure 
of the communication path 21, further, any convection of water being 
heated toward the water supply chamber 19 can be prevented during the 
energization of the heater means 24, whereby the vapor generating 
efficiency can be additionally increased. 
When the user releases his depression of the push button 38, on the other 
hand, the valve rod 36 returns to its upper position due to the returning 
force of the spring 48, the closure flange 40 which has been closing so 
far the vapor release vent 39 together with the closing by the tip end 
portion 23 of the communication path 21 is separated from the vapor 
release vent 39 and, simultaneously, the releasing of the tip end portion 
23 from the communication path 21 and of the actuating arm 49 from the 
microswitch 50 is achieved. Any vapor remained in the vaporizing chamber 
16 at this time is gradually discharged to the exterior of the front wall 
15 through the vapor release path of the vent 39, space 51 and duct 53 
which is rather winding than to be straight, rendering the vapor discharge 
velocity to be relatively slow, so that any risk of causing such vapor to 
be ejected from the atomized vapor outlet 13, top cover 14 or the like can 
be prevented to eliminate any possibility that the user gets burnt. Upon 
the upward shift of the valve rod 36 causing its arm 49 separated from the 
microswitch 50, further, the power supply circuit is turned off and the 
heater means 24 is deenergized so that, when the use of the inhalator is 
stopped, no continuous vapor ejection will occur. In addition, the upward 
shift of the valve rod 36 causes water to be soon supplied to the 
vaporizing chamber 16, so that the vaporizing chamber 16 can never become 
vacant and can be prevented from, for example, being heated without water.