JP2003261307A - Oxygen pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently operate an oxygen pump without the dew condensation of steam even when gaseous oxygen is discharged from a high temperature high humidity atmosphere. <P>SOLUTION: The oxygen pump is composed of an oxygen pump element 21 on both surfaces of which electrodes are formed and a water-repellently treated heat insulating material 33 arranged to surround a heating means 29 and having air permeable function 34. The oxygen pump has high durability and is capable of effectively discharging gaseous oxygen and being used sanitarily without the dew condensation of steam contained in air flowing into the oxygen pump element by applying water repellent treatment on the heat insulating material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oxygen pump.

[0002]

2. Description of the Related Art Heretofore, as an oxygen pump of this kind, there has been one described in, for example, Japanese Patent Application Laid-Open No. 11-23525. FIG. 5 shows the conventional oxygen pump described in the above publication.

In FIG. 5, 1 is a housing, 2 is an oxygen pump element composed of a first electrode 3 formed on a porous substrate 3 such as alumina, an oxygen ion conductive thin film 4 and a second electrode 4. , 7 are heating means composed of a heater wire 9 formed by patterning a conductive paste by screen printing on an insulating substrate 8 such as an alumina substrate.
Are not contained in the housing 1 and are arranged in a state of being opened to the atmosphere.

In this structure, when a voltage is applied to the heating means 7 to generate heat, the oxygen pump element is heated to a temperature at which it operates as an oxygen pump, and a negative voltage is applied to the first electrode 3 and a positive voltage is applied to the second electrode. , The first electrode 3 as indicated by the arrow in the figure
The oxygen in the air that has been dissociated and adsorbed by is carried by the oxygen pump element 2 to the second electrode 4 as oxygen ions, and becomes oxygen molecules and released into the atmosphere. Thereby, the oxygen concentration in the container attached to the housing 1 can be reduced.

[0005]

However, in the configuration of Japanese Patent Laid-Open No. 11-23525, for example, the housing 1
When the atmosphere in the container attached to is hot and humid, water vapor condenses on the surface of the oxygen pump element on the air inflow side, and oxygen cannot be efficiently discharged.

In addition, such dew condensation of water vapor easily causes stains, and bacteria and molds propagate on the stains, resulting in problems in appearance and hygiene.

The present invention is to solve the above-mentioned conventional problems, and at least a part of a heat insulating material having a ventilation function arranged so as to surround an oxygen pump element and a heating means for heating the oxygen pump element is treated to be water repellent. By doing so, it is an object to provide an oxygen pump which can prevent dew condensation of water vapor and can be used efficiently and sanitarily.

[0008]

In order to solve the above-mentioned conventional problems, the oxygen pump of the present invention comprises a first electrode formed on one surface of an oxygen ion conductive substrate and another surface formed on the other surface. An oxygen pump element having a second electrode, at least one heating means for heating the oxygen pump element, and a heat insulating material having a ventilation function arranged so as to surround the heating means. By subjecting at least a part of the water-repellent treatment to water-repellent treatment, water vapor contained in the air flowing into the oxygen pump element can efficiently discharge oxygen without dew condensation on the surface of the heat insulating material.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 has a ventilation function which is arranged so as to surround an oxygen pump element having electrodes formed on both surfaces of an oxygen ion conductive substrate and a heating means for heating the oxygen pump element. Since at least a part of the heat insulating material has a water repellent treatment, the water vapor contained in the air does not condense on the surface of the heat insulating material, so the oxygen molecules contained in the air can be efficiently removed without impairing the ventilation function of the heat insulating material. Can be sent to the oxygen pump element. At the same time, it is possible to prevent the heat insulating material from deteriorating due to the dew condensation of the water vapor, so that the heat efficiency of the heating means for the oxygen pump element is not impaired and it can be used for a long time.

According to the second aspect of the present invention, the water repellent treatment of the heat insulating material having a ventilation function is performed on the surface on the air inflow side of the heat insulating material.
Since the surface of the heat insulating material is protected by the higher density treatment, it is possible to more efficiently prevent the heat insulating material from deteriorating due to dew condensation of water vapor.

According to the third aspect of the invention, the water repellent treatment agent for water repellent treatment of the heat insulating material having the ventilation function is at least one selected from organic silicon compounds, so that an excellent water repellent effect is obtained. Can be demonstrated.

According to a fourth aspect of the invention, the water repellent treatment agent for water repellent treatment of the heat insulating material having a ventilation function is at least one selected from silane-based surfactants having reactivity with the heat insulating material. By chemically bonding to the surface of the heat insulating material, the heat insulating material and the water repellent agent can be integrated, so that the durability of the water repellent performance can be further enhanced.

According to the fifth aspect of the present invention, the heat insulating material having a ventilation function is made of inorganic oxide particles having fine voids, thereby facilitating physical and chemical support of the water repellent treatment agent. As a result, high water repellency can be realized, and at the same time, excellent heat insulation performance can be achieved by the minute voids suppressing the convection of air and reducing the heat conduction of the heat insulating material.

According to the invention described in claim 6, the same effect as in claim 5 can be obtained by using silica (SiO 2) particles as a main component of the heat insulating material having a ventilation function, but further excellent durability. In addition to being able to secure the above, it is possible to prevent the structure of the minute voids from being destroyed, and it is possible to realize the initial excellent heat insulating performance for a long period of time.

According to a seventh aspect of the present invention, the heat ray reflecting means having at least one hole is provided between the heat insulating material having a ventilation function on the side where the heating means is arranged and the heating means. Since the radiant heat from the heating means can be reflected toward the oxygen pump element, the heat efficiency to the oxygen pump can be improved, and at the same time, it becomes difficult to transfer the heat to the water-repellent heat insulating material. It is possible to prevent thermal deterioration of the water-repellent treatment of the material and further improve durability.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a sectional view of an oxygen pump according to a first embodiment of the present invention. In FIG.
Reference numeral 21 denotes an oxygen pump element. The oxygen pump element 21 has a structure in which a first electrode 23 is formed on one surface of an oxygen ion conductive substrate 22 and a second electrode 24 is formed on the other surface. It is connected to an oxygen pump drive power supply circuit 25 for applying a DC voltage to 21 via lead wires 26 and 27. As the oxygen ion conductive substrate 22, yttrium-doped zirconia (YSZ) or samarium-doped ceria (SDC) is used. Further, as the first electrode 23 and the second electrode 24, platinum (P
t), silver (Ag), samarium-strontium-cobalt composite metal oxide (SSCO), or the like, a baked film or a vapor-deposited film is used. When the first electrode 23 acts as a cathode electrode, the second electrode 24 acts as an anode electrode.

Reference numeral 28 is a partition means for partitioning the space on the side of the first electrode 23 and the space on the side of the second electrode 24.
Has an opening portion facing to, and is bonded to the oxygen pump element 21 with an adhesive material such as glass. In the present embodiment, the partition means 28 is arranged on the first electrode 23 side, but it may be arranged on the second electrode 24 side. As the partitioning means 28, a metal plate or foil of nickel, iron-chromium alloy, titanium, gold, platinum or the like, or a ceramic plate of alumina, mullite or the like is used, but the difference in thermal expansion from the oxygen pump element 21 is small and thermal strain is small. Since it is required to be small, a metal foil of nickel or iron-chromium alloy is preferable.

A heating means 29 is provided below the oxygen pump element 21, and is connected to a heating power source 30 for applying electric power to the heating means 29 via lead wires 31 and 32. As the heating means 29, a heating wire or foil of iron-chromium alloy, nickel-chromium alloy or the like is used.

Reference numerals 33 and 34 denote heat insulating materials having a ventilation function, and are composed of porous bodies having a large number of communicating holes. The heat insulating material 33 on the air inflow side is treated to be water repellent. The casing 35 is located so as to cover the oxygen pump element 21, the partitioning means 28, and the heating means 29, and has an opening so that air from the atmosphere and oxygen can flow out into the atmosphere.
It is stored in. Insulation material 33 having this ventilation function,
As 34, an aggregate of silica particles whose main component is an inorganic oxide is used.

FIG. 2 is a schematic view of the heat insulating materials 33 and 34 having the ventilation function, which are composed of the above-mentioned aggregate of silica particles, and have a structure having fine voids 37 by the silica particles 36. An example of the heat insulating material having this structure is Microtherm (trade name) manufactured by Nippon Aerosil Co., Ltd.
The heat-insulating material 33 on the air inflow side has a water repellent 3 on the surface of the silica fine particles.
8 is carried. As a water repellent for water repellent insulation,
As the silane-based compound, a methylhydrogenpolysiloxane, a dimethylpolysiloxane, a methylphenylpolysiloxane, a diphenylpolysiloxane, etc., whose one end is amino-modified, or an epoxy-modified one,
Examples thereof include those modified with carboxy, those modified with carbinol and those modified with methacryl, but are not limited thereto. Further, as a silane-based surfactant chemically bonded to the surface of the heat insulating material, a general formula: CH3 (CH2) n
SiRqX3-q [representing each integer of n = 0 to 30, q = 0 to 2, R represents an alkyl group, and X represents a halogen atom or an alkoxy group] or CH3 (CH2) nA (CH2) qSi ( CH
3) qX3-q [n = 0 to 10, p = 5 to 25, and q = 0 to 2 represent each integer, and A represents an oxygen atom (-O-), an oxycarbonyl group, or a dimethylsilyl group (-Si ( CH3) 2-) and X represents a halogen atom or an alkoxy group], for example, a silane-based surfactant containing (1) CH3CH2O (CH2) 15SiCl3 (2) CH3 (CH2) 2Si (containing a chlorosilyl group. CH3) 2 (CH2)
15SiCl3 (3) H (CH2) 6Si (CH3) 2 (CH2) 9S
Examples thereof include iCl3 (4) CH3COO (CH2) 15SiCl3 (5) CH3 (CH2) 9SiCl3, but are not limited thereto.
Also, a substance in which a chlorosilyl group is replaced with an alkoxysilyl group can be used.

Examples of the method for water-repellently treating a heat insulating material having a ventilation function using these water repellent agents include spraying, dipping, brushing and the like, which impairs the ventilation function of the heat insulating material. If not, either method may be used.

The operation and action of the oxygen pump configured as described above will be described below.

First, when electric power is applied to the heating means 29 by the heating power source 30, the heating means 29 rises in temperature and heats the oxygen pump element 21. Next, a voltage is applied to the oxygen pump element 21 by the oxygen pump driving power supply 25 with the first electrode 23 as the cathode and the second electrode 24 as the anode. In this state, the oxygen pump element 21 is heated to 500 by the heating means 29.
When the temperature is raised to ˜800 ° C., oxygen molecules existing in the space on the first electrode 23 side are taken into the oxygen ion conductive substrate 22 as oxygen ions from the first electrode 23 and reach the second electrode 24. The oxygen ions that have reached the second electrode 24 become oxygen molecules and are released to the external space on the second electrode 24 side. First
Since the space on the side of the electrode 23 and the space on the side of the second electrode 24 are separated by the partitioning means 28, oxygen molecules always present in the space on the side of the first electrode 23 can be transported to the space on the side of the second electrode. . Oxygen molecules in the space on the first electrode 23 side are the second electrode 2
When transported to the space on the fourth side, the oxygen concentration on the side of the first electrode 23 decreases, and the air containing oxygen molecules in the atmosphere has a ventilation function and diffuses through the communication holes of the water-repellent heat insulating material 33. And first
It flows into the space on the electrode 23 side. At this time, even when water vapor is contained in the atmosphere, dew condensation does not occur due to the effect of the water repellent 38 carried by the heat insulating material 33. Meanwhile, the second
From the space on the electrode 24 side, oxygen molecules released from the second electrode 24 diffuse in the heat insulating material 34 having a ventilation function and flow out into the atmosphere. While the oxygen pump element is operating, oxygen molecules continue to be transported as indicated by the arrow in the figure. At this time,
When the container is attached to the first electrode 23 side so as to be hermetically closed, the oxygen concentration in the container can be reduced.

As described above, in the present embodiment, the oxygen pump element 21, the partition means 28 for partitioning the space, and the heating means 29 for heating the oxygen pump element 21 are provided with a ventilation function so as to be water repellent. By arranging the heat insulating material 33 and the heat insulating material 34 having a ventilation function, oxygen molecules do not condense on the surface of the heat insulating material by water vapor contained in the air and oxygen molecules pass through the heat insulating material 33, 34. Since it can be allowed to flow into and out to the atmosphere, the performance as an oxygen pump can be efficiently exhibited.

FIG. 3 shows a comparative example having the same structure as that of the oxygen pump of the first embodiment, except that the heat insulating material is not subjected to the water repellent treatment, and the oxygen pump is sealed on the first electrode 23 side. The figure shows the operating characteristics when the oxygen pump is operated after mounting and adjusting the inside of the container to an atmosphere of 60 ° C. × 98% RH. As is clear from the figure, Example 1
It can be seen that the oxygen pump of 1 reaches the same oxygen concentration faster. This indicates that the oxygen pump of Example 1 in which the heat-insulating material on the air inflow side is treated with water repellent is less susceptible to water vapor than the comparative example. Also (Table 1)
One cycle is until the oxygen concentration in the container reaches a predetermined value, and after one cycle, after introducing air into the container, adjust the atmosphere to 60 ° C x 98% RH and operate the oxygen pump. This is a comparison of the appearances of the heat insulating materials after repeated 50 cycles. Example 1
It can be seen that the heat insulating material of the oxygen pump of No. 3 is less deteriorated than the comparative example.

[0027]

[Table 1]

(Embodiment 2) FIG. 4 is a sectional view of an oxygen pump according to a second embodiment of the present invention. Reference numeral 40 is a heat ray reflecting means, and 41 is a hole provided in the heat ray reflecting means 40. The difference from the configuration of the first embodiment is that it has a ventilation function on the side on which the heating means 29 is arranged and is water-repellently insulated. The point is that the heat ray reflection means 40 having holes 41 provided on the surface of the material 33 is arranged. In the figure, the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Oxygen molecules contained in the air have a ventilation function, and flow into the oxygen pump element 21 through a large number of communication holes existing in the water-repellent heat insulating material 33 and holes 41 provided in the heat ray reflecting means 40. The oxygen molecules released from the oxygen pump element 21 flow out into the atmosphere through a large number of communication holes existing in the heat insulating material 34 having a ventilation function in the upper part. Heat ray reflection means 4
As 0, a material that highly reflects heat radiated at a temperature of 500 to 800 ° C. and a material having heat resistance are desirable, and a plate material such as stainless steel, iron-chromium alloy, titanium, platinum, gold, or foil is used. To be

Radiant heat from the heating means 29 can be reflected toward the oxygen pump element 21 by the heat ray reflecting means 40, so that the heat efficiency to the oxygen pump element 21 can be further improved and at the same time the heat insulating material can be provided. Since heat is less likely to be transferred, it is possible to prevent thermal deterioration of the water repellent treatment and further improve durability.

The oxygen pump of the present invention is applied to a device requiring a low oxygen atmosphere such as a food storage, or conversely to a device requiring an oxygen concentration higher than that in the atmosphere.

[0032]

As described above, according to the present invention, the heat insulating material constituting the oxygen pump is subjected to the water repellent treatment, so that the heat insulating material due to the dew condensation of water vapor even when oxygen is discharged from the hot and humid atmosphere, for example. The oxygen pump performance can be fully exerted while minimizing the effects of deterioration, and it can be used hygienically for a long time.

[Brief description of drawings]

FIG. 1 is a sectional view of an oxygen pump according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a water-repellent heat insulating material having a ventilation function in Example 1 of the present invention.

FIG. 3 is a diagram showing operating characteristics of the oxygen pump according to the first embodiment of the present invention.

FIG. 4 is a sectional view of an oxygen pump according to a second embodiment of the present invention.

FIG. 5 is a sectional view of an oxygen pump in a conventional example.

[Explanation of symbols]

21 Oxygen pump element 22 Oxygen ion conductive substrate 23 First electrode 24 Second electrode 28 compartment means 29 Heating means 33,34 Insulation material with ventilation function 36 silica particles 37 Micro voids 38 Water repellent 40 heat ray reflection means 41 holes

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Baku Nagai             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Villa Daisuke             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 4G042 BA11 BA25

Claims (7)

[Claims] 1. An oxygen pump element having a first electrode formed on one surface of an oxygen ion conductive substrate and a second electrode formed on the other surface, and at least one heating element for heating the oxygen pump element. Means and a heat insulating material having a ventilation function, which is arranged so as to surround the oxygen pump element and the heating means, at least a part of the heat insulating material is treated to be water repellent. Oxygen pump to do. 2. A water repellent treatment of a heat insulating material having a ventilation function,
The oxygen pump according to claim 1, wherein the surface of the heat insulating material on the air inflow side is processed with a higher density. 3. The oxygen pump according to claim 1, wherein the water repellent treatment agent for water repellent treatment of the heat insulating material having a ventilation function is at least one selected from organic silicon compounds. 4. A water repellent treatment agent for water repellent treatment of a heat insulating material having a ventilation function is at least one selected from silane-based surfactants having reactivity with the heat insulating material, and the surface of the heat insulating material is chemically treated. It is combined, It is characterized by the above-mentioned.
The oxygen pump according to any one of 1. 5. The oxygen pump according to claim 1, wherein the heat insulating material having a ventilation function is composed of inorganic oxide particles having fine voids. 6. The oxygen pump according to claim 1, wherein a main component of the heat insulating material having a ventilation function is silica (SiO 2) particles. 7. The heat ray reflecting means having at least one hole is provided between the heat insulating material having the ventilation function on the side where the heating means is arranged and the heating means. The oxygen pump according to the item.