Gas and liquid contact apparatus – Contact devices – Atomizer type
Reexamination Certificate
2000-05-17
2002-01-15
Bushey, C. Scott (Department: 1724)
Gas and liquid contact apparatus
Contact devices
Atomizer type
C261S029000, C429S010000
Reexamination Certificate
active
06338472
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mist atomizer and a mist atomizing device for fuel cells. More particularly, the present invention relates to a mist atomizer for atomizing mists, for example to humidify process gases to be supplied to electrodes of a solid polymer fuel cell, and a mist atomizing device for fuel cells using the mist atomizer.
2. Description of Related Art
Conventionally, this type of mist atomizer is used as a humidifier device for process gases supplied to an anode or a cathode of a solid polymer fuel cell (the process gases are a fuel gas in the case of anode and an oxidizing gas in the case of cathode). A solid polymer fuel cell is a type of fuel cell that generates electromotive force (electric energy) by electrochemical reactions in which protons generated from a fuel supplied to the anode transfer to the cathode through an electrolyte membrane and react with an oxidizing gas supplied to the cathode to produce water.
In order to operate the solid polymer fuel cell normally, it is necessary to keep the electrolyte membrane in an appropriate wet state. A general practice to meet this end is to humidify process gases such as a fuel gas supplied to the anode or an oxidizing gas supplied to the cathode by adding mists or steams thereto.
One example of a fuel cell comprising this type of humidifier device using mists is a solid polymer fuel cell disclosed in Japanese Unexamined Patent Publication No. HEI 5-54900. The solid polymer fuel cell comprises a process gas humidifier device for adding mists to a fuel gas or an oxidizing gas by using a mist atomizer having a spray nozzle or an ultrasound atomizer apparatus.
Application of the humidifier device using mists to a fuel cell is advantageous in that mists are transferred as they are to the electrode on the process gases as a carrier, and thus the amount of humidifying water is quantitatively controlled. Further, there is another advantage. That is, the process gases are deprived of latent heat of evaporation when the mists atomize into steams, a cooling effect is expected to take place on the process gases.
On the other hand, one preferred embodiment of this type mist atomizer, an example of which is shown in
FIG. 7
, is disclosed in Japanese Unexamined Patent Publication No. SHO 57-42362 although its use is not limited to fuel cells. A mist atomizer
70
disclosed in this publication comprises a plurality of (two, in this figure) nozzle heads
74
a
and
74
b
spaced uniformly with respect to the central axial line X—X of a nozzle assembly
72
. Each of the nozzle heads
74
a
and
74
b
has an air intake conduit
76
and a liquid intake conduit
78
each for introducing pressurized air and liquid respectively. Further, each of the nozzle heads
74
a
and
74
b
is provided with a two-fluid nozzle at a particular crossing angle which has a double-pipe construction comprising an air discharge conduit
82
and a liquid discharge conduit
80
.
In the case of the mist atomizer disclosed in this publication, pressurized air is supplied through the gas intake conduit
76
accommodated in each of the nozzle heads
74
a
and
74
b
. When the pressurized air is atomized from the air discharge conduit
80
, liquid supplied through the liquid conduit
78
is sucked into the liquid discharge conduit
82
and atomized therefrom to generate mists. In addition, the mists atomized from each of the nozzle heads
74
a
and
74
b
collide with each other at a point of intersection on the central axis line X—X, and fine mists having particles of ten microns or less are generated through the collision of the jets.
The mist atomizer disclosed in the above-mentioned Japanese Unexamined Patent Publication No. SHO 57-42362 is capable of effectively generating fine mists and of diffusing the mists in the air. However, an order of tens of meters (m) of a spatial extent is required to diffuse the generated mists evenly. In other words, the mist atomizer disclosed in this publication is effective to evenly humidify a wide space such as a room, a factory or a hospital.
On the other hand, in the case of the above-described fuel cell, for the sake of miniaturization of a fuel cell (ensuring its vehicle-mountability) and high power output and high output density of the fuel cell, a gas channel provided in the fuel cell is extremely narrow and inside of the gas channels is a closed space which requires pressure control. In addition, since another components such as a gas supply source are connected by pipes and the like, a sufficient space required to diffuse mists atomized from the two-fluid nozzle can not be secured. For this reason, mere application of the conventional mist atomizer using a two-fluid nozzle to a fuel cell ends up with a problem. That is, since the generated mists are not diffused sufficiently and collide with an inner wall of the channel, the mists are trapped on the wall before being converted into electric power.
In addition, since the utilization efficiency of water supplied to the two-fluid nozzles becomes extremely low, there is a problem that is the need to keep a larger amount of supply water. Further, liquid pools undesirably generated within the channel may be a factor to cause closing of a gas flow (flooding), which hinders stable generation of electric power.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide a mist atomizer capable of generating fine mists (about 30 &mgr;m or less in diameter) in a stable and continues manner even in a closed space which requires pressure control.
Another object of the present invention is to apply such a high-performance mist atomizer to a humidifier device for maintaining electrolyte membranes of a solid polymer fuel cell in an appropriate wet state so as to provide a mist atomizing device for fuel cells which can achieve stable performance of the fuel cell.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, a mist atomizer comprises a plurality of two-fluid nozzles arranged so that mists atomized therefrom collide with each other, and a secondary gas intake conduit for supplying a secondary gas toward a collision point of the mists.
In addition, it is preferred that the mist atomizer of the present invention further comprises flow control means for preventing the secondary gas from interfering with collision of the mists, and for promoting fine mists generated by the collision to mix with the secondary gas. Also, it is preferred that the mist atomizer further comprises a secondary nozzle disposed at a downstream end of the secondary gas intake conduit for promoting the fine mists generated by the collision of the mists to mix with the secondary gas, and for reducing a cross sectional spray area of the secondary gas.
According to the mist atomizer of the present invention having a construction as above, mists atomized from each two-fluid nozzle collide with each other at a point within the secondary gas intake conduit, thereby generating fine mists. In addition, since the secondary gas is supplied toward the collision point of the mists, the fine mists generated by the collision are accelerated by the secondary gas and promoted to mix with the secondary gas. Also, by provision of flow control means in the secondary gas intake conduit, the secondary gas is prevented from interfering with the collision of the mists atomized from each two-fluid nozzle, and the thus generated fine mists are promoted to mix with the secondary gas. Further, if the secondary nozzle is dis
Aoki Hiroshi
Shimazu Takashi
Bushey C. Scott
Kabushiki Kaisha Toyota Chuo Kenkyusho
LandOfFree
Mist atomizer and mist atomizing device for fuel cells does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mist atomizer and mist atomizing device for fuel cells, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mist atomizer and mist atomizing device for fuel cells will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2859750