JP3377229B2 - Atmosphere gas filter regeneration method for soldering - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for measuring an oxygen concentration in an atmospheric gas of a soldering apparatus, which absorbs a combustible gas contained in an oxygen concentration analysis gas. The present invention relates to a method of reproducing a filter to be removed. 2. Description of the Related Art Generally, in a reflow or flow soldering apparatus, a low oxygen concentration in a soldering chamber (hereinafter referred to as a chamber) in which the oxygen concentration is lower than that of the atmosphere by the introduction of nitrogen gas or the like. The soldering is performed in a concentration atmosphere gas. In order to monitor whether the atmosphere gas in the chamber is maintained at a predetermined low oxygen concentration,
Oxygen concentration analysis gas from chamber (sampling gas)
Is sucked and taken into an oximeter, and the oxygen concentration is measured. In this case, if the combustible gas (alcohol or the like) generated in the soldering line is contained in the sampling gas, the detection tube in the oxygen concentration meter is heated to a high temperature of about 700 ° C. The combustible gas and oxygen react (oxidation reaction) in the detection tube, and the oxygen concentration meter displays an extremely low oxygen concentration. Therefore, the sampling gas is passed through a filter for adsorbing flammable gas (activated carbon filter), the flammable gas is adsorbed and removed by this filter, and then taken into an oxygen concentration meter so that accurate concentration detection can be obtained. I have. The activated carbon filter has a limit in the amount of combustible gas that can be adsorbed. For example, when the alcohol concentration in the sampling gas is high or the operation is performed for a long time, the amount of adsorbed combustible gas is saturated and the amount of combustible gas to the oxygen concentration meter is reduced. A leak occurs,
Since the oxidation reaction as described above occurs and the concentration display becomes incorrect, such a saturation filter is discarded and replaced with a new one. As described above, conventionally, activated carbon is regarded as a consumable part. However, conditions such as a difference in frequency of use, a used flux, a type of a work, and a volatile component in a solder paste are considered. Due to various changes, a general exchange cycle cannot be specified. Therefore, it is not economical to cope with conventional regular filter replacement and it is not economical. Also, since the life of the activated carbon filter is shortened when the flow rate of the sampling gas is large, the sensitivity of the activated carbon filter is reduced when the flow rate of the sampling gas is reduced. The present invention has been made in view of the above points, and a filter for adsorbing and removing a combustible gas contained in an oxygen concentration analysis gas in a system for measuring an oxygen concentration in an atmosphere gas of a soldering apparatus. It is an object of the present invention to provide a method capable of effectively reproducing. SUMMARY OF THE INVENTION The present invention relates to a method for adsorbing a combustible gas from an oxygen concentration analysis gas taken out of a soldering chamber filled with an atmosphere gas having a low oxygen concentration during operation of a soldering apparatus. In the oxygen concentration measurement system of the atmosphere gas for soldering which is taken into the oxygen concentration meter through the filter of (1), the regeneration gas for the filter is replaced with the regeneration gas at least at one of the heating start-up time and the stop-down time of the soldering apparatus. heating
A method of regenerating an atmosphere gas filter for soldering, wherein the filter is heated by a heater for passing through the filter for a predetermined time. According to the present invention, a filter regenerating gas such as a flammable gas or a nitrogen gas containing no impurities that may be deposited can be regenerated when the soldering apparatus is heated up or shut down .
The filter is regenerated by being heated by a gas heating heater and passing through the filter for a certain period of time. The present invention will be described below in detail with reference to an embodiment shown in FIG. First, the piping system for measuring oxygen concentration will be described. A reflow soldering apparatus A for applying hot air generated by a heater 11 and a convection fan 12 to a work or molten solder 14 jetted from a nozzle 13 is brought into contact with the lower surface of the work. The flow type soldering apparatus B performs soldering in a low-oxygen-concentration atmosphere gas in a soldering chamber (hereinafter, referred to as a chamber 15) in which the oxygen concentration is reduced by supplying nitrogen gas or the like. In order to monitor whether or not the atmospheric gas in the chamber 15 is maintained at a predetermined low oxygen concentration, a pipe 21 for extracting an oxygen concentration analysis gas (sampling gas) from the chamber 15 is drawn out. The line 21 is connected to a flux catcher 22 for removing the flux in the sampling gas, the line 23 passing through the catcher 22 is connected to a switching valve 24, and the line 25 passing through the switching valve 24 is combustible. A line 27 connected to a filter for activated gas adsorption (activated carbon filter) 26, a line 28 drawn out from the filter 26 passes through a branched line 29 and a switching valve 30, and an oxygen concentration meter comprising a zirconia sensor or the like. Connected to 31. The filter regeneration piping system will be described. One end of a tubular heater 43 for heating regeneration gas is connected to a filter regeneration gas supply source 41 such as a nitrogen cylinder containing liquid nitrogen via a pipe 42. A pipe 44 drawn from the other end of the heater 43 is connected to a pipe 27 to the activated carbon filter 26 via a switching valve 45, and further, a regeneration gas exhausted from a pipe 28 drawn from the activated carbon filter 26. Line 46 branches off,
A switching valve 47 is provided in the pipeline 46. A temperature sensor 48 for controlling the heater 43 is provided in the pipe line 27 to the activated carbon filter 26, and the temperature (100 to 150 ° C.) of the regeneration gas supplied to the activated carbon filter 26 is set by the sensor 48. Is kept. The switching valves 24, 30, 45, and 47 may be manually switched, but by using solenoid valves, the switching can be easily performed. Next, the operation of this embodiment will be described. During the normal operation of the soldering apparatus A or B, the switching valves 24 and 30 are opened and the switching valves 45 and 47 are closed, so that the chamber 15 filled with an atmosphere gas having a low oxygen concentration (mainly nitrogen gas) is opened. The sampling gas for oxygen concentration analysis is taken out, the flux in the sampling gas is removed by the flux catcher 22, and the combustible gas such as alcohol is removed by adsorption with the activated carbon filter 26. Then, the oxygen concentration of the atmospheric gas in the chamber is measured. When the oxygen concentration in the chamber rises above the reference value, an inert gas such as nitrogen is blown into the chamber 15 by a nitrogen supply means (not shown) to control the oxygen concentration in the chamber to decrease. The switching valves 24 and 30 are closed at the time of one or both of the heating start (immediately before the start of operation) and the stop / fall (immediately after the stop of operation) of the soldering apparatus A or B. The switching valves 45 and 47 are opened, and pure (no combustible gas or impurities that can be deposited) nitrogen gas obtained by vaporizing liquid nitrogen from the filter regeneration gas supply source 41 is supplied to the heater 43 by the heater 43. After heating to 150 ° C., this high-temperature nitrogen gas is supplied into the activated carbon filter 26 as a filter regeneration gas, and the activated carbon is continuously passed through the activated carbon in the filter for a certain period of time (about 20 minutes). Regenerate with pure gas. The filter regeneration gas is not limited to nitrogen gas, but may be air as long as it does not contain flammable gas or impurities that may be deposited. It may be supplied to a filter. Further, the heater 43 is connected to the activated carbon filter 26.
However, it may be an integral type. That is, a heater is wound around the activated carbon filter 26,
By heating the regeneration gas supplied to 26, as a result, the filter regeneration gas may be heated and passed through the filter. Although the switching valves 24, 30, 45, and 47 are two-port switching valves, the two switching valves 24 and 45 are one three-port switching valve, and the other two switching valves 30, 47 are different. May be integrated as one three-port switching valve. The switching timing of the switching valves 24, 30, 45, and 47 may be determined by a person in charge, but may be automatically performed according to the temperature in the chamber or by a timer or the like. According to the present invention, the filter regeneration gas is supplied to the soldering apparatus by the heater for heating the regeneration gas at least at one of the start-up time and the stop-down time of the soldering apparatus. By heating and passing through the filter for a certain time,
90% or more of the filter function can be regenerated by the regeneration operation during the automatic operation cycle, and long-term maintenance-free operation can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a piping diagram showing one embodiment of a filter regeneration method of the present invention. [Description of Signs] A, B Soldering Equipment 15 Soldering Room (Chamber) 26 Filter 31 Oxygen Analyzer 43 Heater

Continuation of the front page (72) Inventor Makoto Iida 591-11 Kamihirose Higashikubo, Sayama City, Saitama Prefecture FA System Factory, Tamura Corporation (56) References JP-A-48-43688 (JP, A) JP-A-4 -1990967 (JP, A) JP-A-62-101372 (JP, A) JP-A-62-101373 (JP, A) JP-A-63-200761 (JP, U) JP-A-63-22512 (JP, Y2) ) Kazunori Oki, "Methods of Countermeasures against CFCs, Automatic Soldering Equipment for Countermeasures against CFCs," Electronics Packaging Technology, Japan, Information Research Committee, Japan, January 20, 1991, Volume 7, No. 2, p. 62-65 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 1/00-1/44 B01D 53/04 B23K 31/02 H05K 3/34 JICST file (JOIS)

Claims (1)

(57) [Claims] [Claim 1] A filter for adsorbing a flammable gas with an oxygen concentration analysis gas taken out of a soldering chamber filled with an atmosphere gas having a low oxygen concentration during operation of a soldering apparatus. In the system for measuring the oxygen concentration of the atmosphere gas for soldering, which is taken into the oxygen concentration meter through the filter, the gas for regenerating the filter is regenerated at least at one of the time of heating-up and the time of shut-down of the soldering apparatus.
A method for regenerating an atmosphere gas filter for soldering, characterized in that the filter is heated by a heater for heating a gas and passed through the filter for a predetermined time.