JP2009242123A - Catalyst apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst apparatus where heat loss can be reduced and where the temperature of nitrogen gas after passing a catalyst can be lowered in the catalyst apparatus. <P>SOLUTION: The catalyst apparatus 200 has a cylindrical catalyst housing body 204 located in a case 205 and a cylindrical partition 203 located so as to surround the periphery of the catalyst housing body 204. The inner peripheral surface of the partition 203 is positioned so as to oppose the outer peripheral surface of the catalyst housing body 204. The outer peripheral surface of the partition 203 is positioned so as to oppose the inner peripheral surface of the case 205. A space formed between the outer peripheral surface of the catalyst housing body 204 and the inner peripheral surface of the partition 203 becomes a first gas flow path 207. A space formed between the outer peripheral surface of the partition 203 and the inner peripheral surface of the case 205 becomes a second gas flow path 208. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a catalyst device used in a nitrogen gas generator that supplies high-purity nitrogen gas.

As a soldering method, an immersion soldering method and a reflow soldering method are known. In any case, by performing soldering in an atmosphere of inert nitrogen gas (N ₂ gas), oxidation can be suppressed, solder defects can be reduced, and soldering quality can be improved. There are effects such as being able to. For example, a device for supplying nitrogen gas into a furnace of a reflow device is described in Patent Document 1 below.

JP-A-6-183705

  FIG. 1 shows a schematic configuration of an example of a reflow apparatus. An object to be heated, on which electronic components for surface mounting are mounted on both sides of the printed wiring board, is placed on a conveyor, and is carried into the furnace body of the reflow apparatus from the carry-in entrance 71. The conveyor conveys the object to be heated in the direction of the arrow (from left to right as viewed in FIG. 1) at a predetermined speed, and the object to be heated is taken out from the carry-out port 72.

  A reflow furnace is sequentially divided into, for example, nine zones Z1 to Z9 along the transfer path from the carry-in entrance 71 to the carry-out exit 72, and these zones Z1 to Z9 are arranged in-line. Seven zones Z1 to Z7 from the inlet side are heating zones, and two zones Z8 and Z9 on the outlet side are cooling zones. A forced cooling unit 73 is provided in relation to the cooling zones Z8 and Z9. In each heating zone, an upper furnace body 74 and a lower furnace body 75 are provided facing each other for heating, and an object to be heated is conveyed through the facing gap. The upper furnace body 74 and the lower furnace body 75 heat the object to be heated by blowing hot air (heated atmosphere gas) onto the object to be heated. Several zone Z1-Z9 controls the temperature of a to-be-heated object according to the temperature profile at the time of reflow.

  The upper furnace body 74 has, for example, a blower configured as a turbo fan, a heater, and a panel (heat storage member) having a large number of small holes through which hot air passes, and the hot air that has passed through the small holes in the panel is heated. Is sprayed from above. The lower furnace body 75 also has the same configuration as the upper furnace body 74, and hot air that has passed through the small holes in the panel is blown against the object to be heated from below.

  A nitrogen gas generation device 76 is provided, and nitrogen gas is injected into the reflow device through a pipe 77 from an injection pipe 78 disposed on the outlet side of the reflow device, for example. You may provide the position of the injection pipe 78 in places other than an exit side. Nitrogen gas injected into the reflow apparatus passes through the furnace body and flows out of the furnace through passages on the inlet side and the outlet side.

  In the nitrogen gas generator 76 of Patent Document 1, when supplying nitrogen to the reflow device, hydrogen is removed from the nitrogen gas in order to reduce the oxygen concentration of the relatively low purity nitrogen gas separated by the membrane separation nitrogen generator. After adding a gas or liquid flammable substance at room temperature, it is passed through a catalyst device to remove oxygen contained in low-purity nitrogen gas.

  In the catalyst device, a catalyst is accommodated in a cylindrical container, and a mixed gas of nitrogen gas and combustible gas passes through the catalyst. The catalyst device uses a noble metal such as palladium (Pd) or platinum (Pt). Nitrogen gas heated in advance by an external preheater is heated by a heater and passes through the catalyst, whereby the combustible substance and oxygen contained in the nitrogen gas undergo catalytic combustion, and nitrogen taken out from the catalyst device The oxygen concentration of the gas is assumed to be lower. Since the nitrogen gas after passing through the catalyst has a high temperature due to its reaction heat, it is cooled by heat exchange with the raw material nitrogen gas in a heat exchanger provided outside, and then moisture is removed by a moisture removing device, Gas is supplied to the reflow device.

  In order to burn the combustible gas with the catalyst, the reaction rate decreases unless the catalyst temperature is set to 150 ° C. or higher. Therefore, the nitrogen gas after passing through the catalyst is in a high temperature state of 150 ° C. or higher. However, if nitrogen gas in a high temperature state is discharged as it is, there is a problem that the heat resistance temperature of the pneumatic equipment and piping material located downstream is exceeded.

  In the catalyst device described in Patent Document 1, since preheating of the gas before passing through the catalyst device is performed by a preheater provided outside, the gas is cooled before flowing into the catalyst device from the preheater, and heat is lost. Resulting in.

  Accordingly, an object of the present invention is to provide a catalyst device that can reduce heat loss and reduce the temperature of nitrogen gas after passing through the catalyst in the catalyst device.

In order to solve the above-described problems, the present invention provides:
A catalyst device that removes oxygen by burning a mixed gas in which a combustible gas is mixed with nitrogen gas containing oxygen with a catalyst,
A catalyst housing for housing the catalyst;
A first partition having an inner peripheral surface facing the outer peripheral surface of the catalyst housing;
A second partition having an inner peripheral surface facing the outer peripheral surface of the first partition, the outer peripheral surface being in contact with the outside air;
A heater for heating the gas passed through the catalyst in the catalyst housing,
A first space is formed by the outer peripheral surface of the catalyst housing and the inner peripheral surface of the first partition, and a second space is formed by the outer peripheral surface of the first partition and the inner peripheral surface of the second partition,
After the mixed gas flows through the first space, it flows into the catalyst housing,
After the gas flowing into the catalyst housing flows through the catalyst, it flows into the second space,
The gas that flows into the second space is a catalyst device that flows to the outside after flowing through the second space.

  In the present invention, heat loss can be reduced by heat exchange, and the temperature of the gas after passing through the catalyst can be lowered in the catalyst device.

  According to this invention, heat loss can be reduced, and the temperature of the gas after passing through the catalyst can be lowered in the catalyst device.

  Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of a catalyst device according to an embodiment of the present invention will be described. FIG. 2 is a cross-sectional view showing the configuration of the catalyst device according to one embodiment of the present invention.

  The catalyst device 200 shown in FIG. 2 is obtained by mixing a combustible gas with a nitrogen gas containing oxygen in order to reduce the oxygen concentration of the relatively low purity nitrogen gas separated by the membrane separation nitrogen generator. It burns with.

  The catalyst device 200 includes a cylindrical catalyst storage body 204 provided in a case 205 and a cylindrical partition wall 203 provided so as to surround the periphery of the catalyst storage body 204.

  A catalyst 202 is carried on the catalyst housing 204. The catalyst 202 uses a noble metal such as palladium (Pd) or platinum (Pt). By passing through the catalyst 202, the combustible substance and the oxygen contained in the nitrogen gas undergo catalytic combustion, and the oxygen concentration of the nitrogen gas taken out from the catalyst device 200 is made lower.

  The inner peripheral surface of the partition wall 203 is provided so as to face the outer peripheral surface of the catalyst housing 204. The outer peripheral surface of the partition wall 203 is provided so as to face the inner peripheral surface of the case 205. A space formed between the outer peripheral surface of the catalyst housing 204 and the inner peripheral surface of the partition wall 203 becomes a first gas flow passage 207. A space formed between the outer peripheral surface of the partition wall 203 and the inner peripheral surface of the case 205 serves as a second gas flow path 208.

  In the catalyst device 200, the gas introduced from the gas inlet 201 is in the order indicated by arrows A to F in FIG. 2, the gas inlet 201 → the first gas flow passage 207 → the heater 206 → the catalyst housing. The gas flows through 204 → second gas flow path 208 → gas outlet 209.

  The gas flowing through the first gas flow passage 207 exchanges heat through the catalyst 202 and the catalyst housing 204, and the temperature rises. At the same time, the gas flowing through the first gas flow passage 207 exchanges heat with the high-temperature gas after passing through the catalyst flowing through the second gas flow passage 208 via the partition wall 203, and the second gas flow passage 208. Reduce the temperature of the gas flowing through.

  After the gas is heated to a predetermined temperature by the heater 206, the combustible gas and oxygen contained in the nitrogen gas are catalytically combusted by passing through the catalyst housing 204. The gas after passing through the catalyst housing 204 has a high temperature of, for example, 150 ° C. or higher and flows into the second gas flow path 208. In order to control the temperature of the gas, a temperature sensor 212 such as a thermocouple for temperature detection, and a detection signal from the temperature sensor 212 are provided, and a temperature control unit 116 that controls the power supplied to the heater 206 is provided.

  The gas flowing through the second gas flow passage 208 is exchanged by heat exchange between the outside of the case 205 and the outer wall of the case 205 and heat exchange between the gas flowing through the first gas flow passage 207 and the partition wall 203. The temperature drops to about 80 ° C. or lower, for example. After passing through the second gas flow passage 208, the gas whose temperature has decreased is led out from the gas outlet 209.

  That is, in the gas path of the catalyst device 200, the gas temperature changes as follows. Gas inlet 201 → first gas flow passage 207 (temperature rise (preheating)) → heater 206 (temperature rise) → catalyst housing 204 → second gas flow passage 208 (temperature drop) → gas outlet 209.

  In the catalyst device 200 according to an embodiment of the present invention, the temperature of the high-temperature gas after passing through the catalyst in the catalyst device 200 can be reduced by heat exchange. Thereby, the gas temperature after passing a catalyst can be made lower than the heat resistance temperature of the pneumatic equipment and piping material located downstream. Further, by configuring the gas flow path in the case 205 in a layered manner, the gas temperature can be increased (preheated) or decreased by heat exchange, thereby realizing a catalyst device with less heat loss.

  Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible. For example, the present invention can be applied to a case where nitrogen gas is supplied to an apparatus other than the soldering apparatus. Further, the shape of the catalyst housing and the shape of the partition walls are not limited to the above-described examples. Further, for example, a plurality of partition walls may be provided, and the gas flow passage may be three or more layers. Furthermore, for example, a configuration in which heat radiating fins are provided in the case may be employed.

It is a basic diagram which shows the outline of the reflow apparatus which can apply this invention. It is a basic diagram which shows the structure of the catalyst apparatus by one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 116 ... Temperature control part 200 ... Catalyst apparatus 201 ... Gas introduction port 202 ... Catalyst 203 ... Partition 204 ... Catalyst storage body 205 ... Case 206 ... Heater 207 ...・ Gas flow passage 208 ... Gas flow passage 209 ... Gas outlet 212 ... Temperature sensor

Claims (3)

A catalyst device that removes oxygen by burning a mixed gas in which a combustible gas is mixed with nitrogen gas containing oxygen with a catalyst,
A catalyst housing for housing the catalyst;
A first partition having an inner peripheral surface facing the outer peripheral surface of the catalyst housing;
A second partition wall having an inner peripheral surface facing the outer peripheral surface of the first partition wall, the outer peripheral surface contacting the outside air;
A heater for heating a gas passed through the catalyst in the catalyst housing,
A first space is formed by the outer peripheral surface of the catalyst housing and the inner peripheral surface of the first partition, and a second space is formed by the outer peripheral surface of the first partition and the inner peripheral surface of the second partition. Formed,
The mixed gas introduced from the outside flows through the first space, and after being heated by the heater, flows into the catalyst housing,
After the gas flowing into the catalyst housing flows through the catalyst, it flows into the second space,
The catalyst device in which the gas flowing into the second space flows out after flowing through the second space.   The catalyst device according to claim 1, further comprising a temperature control unit that controls a temperature of the heater.   The catalyst device according to claim 1, wherein the nitrogen gas containing oxygen is obtained through a nitrogen separation membrane.

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