Patent Description:
A reflow apparatus has been known as an example of apparatuses that solder electronic components to printed circuit boards. In the reflow apparatus, for ease of maintenance, a structure in which a housing of an upper furnace body is superimposed in a separable manner on a lower furnace body has been employed. A superimposed part of the furnace bodies is sealed with a gasket such that in-furnace air is prevented from leaking to the outside. By preventing the in-furnace air from leaking to the outside, in-furnace heating efficiency can be maintained. In addition, N<NUM> reflow apparatuses including furnaces in which a nitrogen atmosphere is maintained for increasing soldering efficiency also have been used. Also in the N<NUM> reflow apparatuses, the nitrogen atmosphere in the furnace can be maintained by preventing the in-furnace air from leaking to the outside. As an example of such reflow apparatuses including the gaskets, an apparatus disclosed in <CIT> has been known
PTL <NUM>: <CIT>.

In the reflow apparatus, boards to which solder paste has been printed in advance are transported into and then heated in a reflow furnace of the reflow apparatus. The gasket that prevents the leakage of the in-furnace air is deteriorated along with heating of the in-furnace air. In addition, when the boards are heated, flux contained in the solder paste is vaporized into flux fumes that waft in the reflow furnace. Adhesion of these flux fumes to the gasket causes corrosion of the gasket. The gasket to which failures such as the deterioration by the heat and the corrosion by the adhesion of the flux fumes have occurred may cause the leakage of the in-furnace air.

In addition, as an example of soldering apparatuses other than the reflow apparatus, there may be mentioned a jet soldering apparatus including a jet solder bath. In this jet soldering apparatus, boards to which flux has been applied in advance are heated during a process of being transported to the jet solder bath, and then soldered with molten solder that is jetted in the jet solder bath. In the heating of the boards and the soldering in the jet solder bath, the flux is vaporized into the flux fumes. As a countermeasure, also in the jet soldering apparatus, the gasket that prevents the in-furnace air and the flux fumes from leaking to the outside of the apparatus is provided as in the reflow apparatus. In such ways, the soldering apparatuses generally include the sealing gaskets that mainly prevent the in-furnace air from leaking to the outside of the apparatuses. However, the gaskets to which the failures such as the deterioration by the heat have occurred may cause the leakage of the in-furnace air.

In the reflow apparatus disclosed in <CIT>, nitrogen is supplied into a furnace while measuring oxygen concentration in the furnace, and it is determined that leakage of nitrogen has occurred in a case where the oxygen concentration in the furnace does not decrease to a predetermined value even after a certain time period has elapsed. In other words, the apparatus of <CIT> requires at least a certain time period to determine whether the oxygen concentration in the furnace has decreased to the predetermined value as a result of the occurrence of the failures of the gasket.

In addition, the reflow apparatus disclosed in <CIT> is incapable of determining whether or not the failures of the gasket have caused the oxygen concentration in the furnace not to decrease to the predetermined value even after the certain time period has elapsed, that is, whether or not the failures of the gasket have caused abnormalities of the oxygen concentration in the furnace.

The present invention has been made to solve the related-art problems as described above, and an object thereof is to detect failures of a gasket more promptly. In addition, another object of the present invention is to determine whether or not abnormalities of oxygen concentration in a furnace (in processing chamber) have been caused by the failures of the gasket.

The present invention achieves at least one of the objects.

According to a first aspect of the present invention, there is provided a soldering apparatus as defined in claim <NUM>, the apparatus including:.

According to the first aspect, the one of the pressure and the concentration of the second gas in the sealed space can be measured after the sealed space has been filled with the first gas. Thus, in a case where the one of the pressure and the concentration of the second gas in the sealed space reaches a predetermined threshold, it can be <NUM> grasped that failures of the gasket have occurred. Further, the sealed space that is defined by the gasket is located to separate the processing chamber and the outside of the furnace, and in addition, can be more easily reduced in volume than the processing chamber. Thus, unlike the related art, leakage of the gas from the sealed space that is narrower than the processing chamber can be detected before occurrence of abnormalities of the concentration of the gas such as oxygen in the processing chamber. As a result, the failures of the gasket can be more promptly detected.

Further embodiments of the first aspect of the present invention are defined in the dependent claims <NUM>-<NUM>.

According to a second aspect of the present invention, there is provided a method of detecting failures of a gasket that seals a furnace body including a processing chamber in which boards are processed, as defined in claim <NUM>, wherein this method of detecting the failures of the gasket includes:.

According to this second aspect of the present invention, the one of the pressure and the concentration of the second gas in the sealed space can be measured after the first gas has been supplied into the sealed space. Thus, in a case where the one of the pressure and the concentration of the second gas in the sealed space reaches a predetermined threshold, it can be grasped that failures of the gasket have occurred. Further, the sealed space that is defined by the gasket is located to separate the processing chamber and the outside of the furnace, and in addition, can be more easily reduced in volume than the processing chamber. Thus, unlike the related art, leakage of the gas from the sealed space that is narrower than the processing chamber can be detected before occurrence of abnormalities of the concentration of the gas such as oxygen in the processing chamber. As a result, the failures of the gasket can be more promptly detected.

Further embodiments of the second aspect of the present invention are defined in the dependent claims <NUM>-<NUM>.

When an atmosphere in the processing chamber is monitored with an oxygen meter, this oxygen meter is connected to an inside of the sealed space. With this, measurement in the processing chamber and measurement in the sealed space can be performed alternately to each other. Thus, the number of components (number of measurement apparatuses) necessary for implementing the method of detecting the failures of the gasket can be suppressed from increasing.

Now, an embodiment of the present invention is described with reference to the drawings. In the drawings referred to below, the same or corresponding components are denoted by the same reference symbols to omit redundant description thereof. Note that, although a reflow apparatus is exemplified as a soldering apparatus of the present invention in the embodiment described below, the soldering apparatus is not limited thereto, and any soldering apparatus in which the gaskets are used as described above may be encompassed within the scope of the present invention.

<FIG> is a schematic top view of the reflow apparatus according to this embodiment. <FIG> is a schematic side view of the reflow apparatus according to this embodiment. As illustrated in <FIG> and <FIG>, this reflow apparatus <NUM> includes a furnace body <NUM>, a carry-in port <NUM>, a carry-out port <NUM>, and a control apparatus <NUM>. The furnace body <NUM> includes therein a processing chamber 110D in which boards (not shown) are processed. The carry-in port <NUM> is an inlet for allowing the boards to which solder paste has been applied (not shown) to be carried into the processing chamber 110D in the furnace body <NUM>. The carry-out port <NUM> is an outlet for allowing the heated boards (not shown) to be carried out of the processing chamber 110D in the furnace body <NUM>. The reflow apparatus <NUM> according to this embodiment need not necessarily include the single carry-in port <NUM> and the single carry-out port <NUM>, and may, for example, include two or more carry-in ports <NUM> and as many carry-out ports <NUM> such that a larger number of boards are processed at the same time.

The reflow apparatus <NUM> includes a transport conveyor (not shown) for transporting the boards, which have been fed through the carry-in port <NUM>, to the carry-out port <NUM>. The furnace body <NUM> includes therein a configuration that heats, from above and below, the boards having been carried in through the carry-in port <NUM>, and then cools the heated boards. Specifically, for example, the furnace body <NUM> includes therein a plurality of heating zones and at least one cooling zone arranged in line. The boards that have been carried in through the carry-in port <NUM> are transported toward the carry-out port <NUM> at a predetermined speed. The boards are preliminarily heated at a preliminary heating portion in one of the heating zones, and then heated to a predetermined temperature at a main heating portion in another one of the heating zones. During these processes, the solder paste on the boards is molten, and flux fumes are generated at the time when the solder paste is molten. In the cooling zone, the boards are rapidly cooled to solidify the solder.

The control apparatus <NUM> is configured, for example, to be capable of controlling an operation of the reflow apparatus <NUM> according to this embodiment, and is communicably connected to the transport conveyor, the heating zones, and the cooling zone (none of which is shown). The control apparatus <NUM> may include, for example, a CPU, a memory that stores operating programs, and a PLC (Programmable Logic Controller) that includes an input/output unit. In addition, the control apparatus <NUM> is configured to be capable of controlling operations of a measuring apparatus <NUM> and a gas supply apparatus <NUM> described below.

The reflow apparatus <NUM> may have the gas supply apparatus <NUM> configured to supply an inert gas such as nitrogen (corresponding to an example of a first gas) into the processing chamber 110D, and the measuring apparatus <NUM>. The measuring apparatus <NUM> may be a gas concentration sensor that measures concentration of a gas such as oxygen (corresponding to an example of a secondary gas). In the reflow apparatus <NUM>, the gas supply apparatus <NUM> supplies the inert gas such as nitrogen such that oxygen concentration in the processing chamber 110D is reduced. The measuring apparatus <NUM> measures the oxygen concentration in the processing chamber 110D. Data of the oxygen concentration measured by the measuring apparatus <NUM> may be transmitted, for example, to the control apparatus <NUM> or an external computer other than the control apparatus <NUM>. This enables an operator to check whether an atmosphere in the processing chamber 110D is normal.

As illustrated in <FIG>, the furnace body <NUM> includes an upper furnace body 110A and a lower furnace body 110B. The upper furnace body 110A and the lower furnace body 110B are coupled to each other with, for example, hinges, and the upper furnace body 110A is configured to be openable/closable on its one side relative to the lower furnace body 110B such that internal maintenance and the like can be performed. In this embodiment, in order that in-furnace air is prevented from leaking through a superimposition plane between the upper furnace body 110A and the lower furnace body 110B, as illustrated in <FIG>, a gasket <NUM> is provided to at least one of the upper furnace body 110A and the lower furnace body 110B. The gasket <NUM> may be formed of an arbitrary sealing material such as a silicone sponge. Specifically, in this embodiment, along a direction in which the carry-in port <NUM> and the carry-out port <NUM> are linked to each other (transport direction of the boards), the gasket <NUM> is provided along both edges of opening portions of the lower furnace body 110B. This prevents the leakage of the in-furnace air under a state in which the upper furnace body 110A and the lower furnace body 110B are closed to each other. Thus, during the process of heating the boards, the flux fumes generated in the furnace body <NUM> also can be suppressed from flowing to an outside of the furnace body <NUM>. Note that, the gasket <NUM> may be provided to the upper furnace body 110A.

In the reflow apparatus <NUM> as described above in this embodiment, the gasket <NUM> is deteriorated along with heating of the in-furnace air. In addition, adhesion of the flux fumes causes corrosion of the gasket <NUM>. The gasket <NUM> to which failures such as the deterioration by the heat and the corrosion by the adhesion of the flux fumes have occurred may cause the leakage of the in-furnace air. As a countermeasure, it is conceivable to detect the leakage of the in-furnace air by measuring concentration of a specific one of the gases in the processing chamber 110D of the furnace body <NUM>. However, it may take time to determine whether or not the concentration of the specific one of the in-furnace gases has reached a predetermined value as a result of the occurrence of the failures of the gasket <NUM>.

In view of such circumstances, in the reflow apparatus <NUM> according to this embodiment, a sealed space isolated from the processing chamber 110D is formed with use of the gasket <NUM> such that the failures of the gasket <NUM> are more promptly detected. <FIG> is a top view of the gasket <NUM> according to this embodiment. <FIG> is a cross-sectional view of the gasket <NUM>, which is taken along arrows <NUM>-<NUM> in <FIG>. As illustrated in <FIG> and <FIG>, the gasket <NUM> according to this embodiment includes a first seal <NUM>, a second seal <NUM>, and a fixation portion <NUM>. The first seal <NUM>, the second seal <NUM>, and the fixation portion <NUM> extend along the direction in which the carry-in port <NUM> and the carry-out port <NUM> illustrated in <FIG> are linked to each other (transport direction of the boards), that is, along each of both the edges of the opening portions of the upper furnace body 110A and the lower furnace body 110B. The first seal <NUM> and the second seal <NUM> are arranged away from each other, and the fixation portion <NUM> is located therebetween.

As illustrated in <FIG>, the first seal <NUM> and the second seal <NUM> respectively have a first sealing surface 12a and a second sealing surface 14a to be held in contact with the upper furnace body 110A. As illustrated in <FIG>, in this embodiment, the first sealing surface 12a and the second sealing surface 14a each have a semi-circular shape in cross-section. Alternatively, the first sealing surface 12a and the second sealing surface 14a may each have an arbitrary protruding shape.

Although the first seal <NUM> and the second seal <NUM> may have thicknesses and shapes different from each other, as illustrated in <FIG>, in this embodiment, the first seal <NUM> and the second seal <NUM> each have substantially the same thickness and substantially the same shape. This enables substantially-uniform pressure application to the first seal <NUM> and the second seal <NUM> under the state in which the furnace body <NUM> is closed. As a result, degrees of deterioration of the first seal <NUM> and the second seal <NUM> can be further equalized to each other.

The fixation portion <NUM> is a plate-like part to be coupled to the first seal <NUM> and the second seal <NUM>. In other words, the fixation portion <NUM> has a function to couple the first seal <NUM> and the second seal <NUM> integrally to each other. The fixation portion <NUM> is located between the first seal <NUM> and the second seal <NUM>, and extends in the same direction as a direction in which the first seal <NUM> and the second seal <NUM> extend. As illustrated in <FIG>, the fixation portion <NUM> has a plurality of through-holes 16a. As described below, by inserting push rivets into the through-holes 16a, the gasket <NUM> can be fixed in an attachable/detachable manner to the furnace body <NUM>.

In addition, as illustrated in <FIG>, the fixation portion <NUM> is thinner than each of the first seal <NUM> and the second seal <NUM>. This configuration prevents the push rivets arranged in the fixation portion <NUM> from protruding higher than the first seal <NUM> and the second seal <NUM> under the state in which the furnace body <NUM> is sealed. In this way, this configuration does not physically influence the sealing of the furnace body <NUM>.

Next, a procedure for attaching the gasket <NUM> illustrated in <FIG> and <FIG> to the furnace body <NUM> is described. <FIG> are views illustrating the procedure for attaching the gasket <NUM> with use of the push rivets. <FIG> illustrate a part of the furnace body <NUM>, where holes 110C that allow the push rivets to be inserted thereinto are provided at corresponding parts in the furnace body <NUM>. As illustrated in <FIG>, a push rivet <NUM> includes a pin <NUM> and a rivet body <NUM>. The pin <NUM> includes a head portion <NUM> and a shaft portion <NUM>. The shaft portion <NUM> includes a tapered part such that a diameter of the shaft portion <NUM> gradually increases toward a distal end of the pin <NUM>. The rivet body <NUM> includes a flange portion <NUM> and a leg portion <NUM> extending from the flange portion <NUM>. The flange portion <NUM> has a hole that allows the pin <NUM> to be inserted thereinto, and the leg portion <NUM> is formed into a substantially cylindrical shape so as to allow the pin <NUM> to be inserted thereinto. The leg portion <NUM> includes notch portions 27a at an end portion on the distal end side of the pin <NUM>.

The gasket <NUM> is attached to the furnace body <NUM> as follows. First, the gasket <NUM> is arranged in the furnace body <NUM>, and as illustrated in <FIG>, the push rivet <NUM> is inserted into the through-hole 16a of the gasket <NUM> and the hole 110C of the furnace body <NUM>. Under the state illustrated in <FIG>, the gasket <NUM> has not yet been fixed to the furnace body <NUM>.

Then, as illustrated in <FIG>, an operator or the like pushes the head portion <NUM> of the pin <NUM> into the rivet body <NUM>. At this time, the shaft portion <NUM> of the pin <NUM> causes the leg portion <NUM> of the rivet body <NUM> to radially expand. With this, the leg portion <NUM> of the rivet body <NUM> is pressed against an inner peripheral surface of the hole 110C of the furnace body <NUM>. In this way, the push rivet <NUM> is fixed to the furnace body <NUM>. The gasket <NUM> is pressed against the furnace body <NUM> by the flange portion <NUM> of the rivet body <NUM>. In this way, the gasket <NUM> is fixed to the furnace body <NUM> by the push rivet <NUM>.

In order to detach the gasket <NUM> from the furnace body <NUM>, as illustrated in <FIG>, the pin <NUM> of the push rivet <NUM> is further pushed in toward the distal end. As a result, a relatively radially-small part of the pin <NUM> comes to an inside of the rivet body <NUM>. With this, the leg portion <NUM> of the rivet body <NUM> is radially shrunk (enters a straight state). In this state, the push rivet <NUM> is pulled out of the through-hole 16a of the gasket <NUM> and the hole 110C of the furnace body <NUM>. In this way, the fixation of the gasket <NUM> is released.

As described above, the gasket <NUM> is fixed in the attachable/detachable manner to the furnace body <NUM> by the push rivet <NUM>. The push rivet <NUM> can be easily attached and detached by the operator, and hence the gasket <NUM> can be easily attached to and detached from the furnace body <NUM>. Further, in this embodiment, by inserting the push rivet <NUM> into the through-hole 16a of the gasket <NUM>, the flange portion <NUM> is brought into direct contact with the gasket <NUM>, whereby the gasket <NUM> can be fixed to the furnace body <NUM>. Still further, in this fixed state, by further pushing in the pin <NUM> of the push rivet <NUM> toward the distal end, and then by pulling the push rivet <NUM> out of the through-hole 16a of the gasket <NUM> and the hole 110C of the furnace body <NUM>, the fixation of the gasket <NUM> is released. With this, efficiency at the time of the operation to attach the gasket <NUM> and maintainability at the time of replacing the gasket <NUM> can be increased to be higher than those in the related-art fixation methods including using screws or bond.

The first seal <NUM> and the second seal <NUM> need not necessarily be fixed with the push rivet <NUM>, and may be fixed to the furnace body <NUM> with an arbitrary adhesive. In addition, in that case, the through-hole 16a of the fixation portion <NUM> may be omitted, or the fixation portion <NUM> itself may be omitted. In other words, the first seal <NUM> and the second seal <NUM> may be fixed as independent members to the furnace body <NUM> with the arbitrary adhesive.

Referring back to <FIG>, the gasket <NUM> is described in detail. As illustrated in <FIG>, the gasket <NUM> further includes a third seal <NUM> and a fourth seal <NUM>. <FIG> is a side view of the gasket <NUM>, which is taken along arrows <NUM>-<NUM> in <FIG>. <FIG> is a side view of the gasket <NUM>, which is taken along arrows <NUM>-<NUM>. The third seal <NUM> and the fourth seal <NUM> are arranged between the first seal <NUM> and the second seal <NUM>, and are configured to effect sealing between the first seal <NUM> and the second seal <NUM>. Similar to the first seal <NUM> and the second seal <NUM>, the third seal <NUM> and the fourth seal <NUM> may be formed of the arbitrary sealing material such as the silicone sponge. The third seal <NUM> and the fourth seal <NUM> may each have an arbitrary shape as long as the sealing between the first seal <NUM> and the second seal <NUM> can be effected. In the example illustrated in <FIG>, the third seal <NUM> and the fourth seal <NUM> each have such a shape that fills a gap between the first seal <NUM> and the second seal <NUM>.

As illustrated in <FIG>, the third seal <NUM> and the fourth seal <NUM> are arranged away from each other. In the example illustrated in <FIG>, the third seal <NUM> is arranged between respective end portions on one side of the first seal <NUM> and the second seal <NUM> (lower end portions in the illustration). The fourth seal <NUM> is arranged between respective end portions on another side of the first seal <NUM> and the second seal <NUM> (upper end portions in the illustration). This enables a sealed space S1 to be elongated along the transport direction of the boards, and hence failures can be detected substantially all over the first seal <NUM> and the second seal <NUM>.

As illustrated in <FIG>, the gaps between the first seal <NUM> and the second seal <NUM> are sealed with the first seal <NUM> and the second seal <NUM> that are away from each other and with the third seal <NUM> and the fourth seal <NUM> that are away from each other. With this, when the furnace body <NUM> is closed, the sealed space S1 is defined by the furnace body <NUM> and the gasket <NUM>. In other words, in the example illustrated in <FIG>, the sealed space S1 is defined at least by the furnace body <NUM>, the first seal <NUM>, the second seal <NUM>, the third seal <NUM>, and the fourth seal <NUM>. This sealed space S1 is isolated from the processing chamber 110D of the furnace body <NUM> to serve as an independent space. In this embodiment, since the gasket <NUM> includes the plurality of seals, specifically, the first seal <NUM>, the second seal <NUM>, the third seal <NUM>, and the fourth seal <NUM>, even in a case where any of these seals is deteriorated, the furnace body <NUM> can remain sealed by other ones of the seals.

The reflow apparatus <NUM> further includes the measuring apparatus <NUM> and the gas supply apparatus <NUM>. These measuring apparatus <NUM> and gas supply apparatus <NUM>, which desirably serve also as the measuring apparatus <NUM> and the gas supply apparatus <NUM> illustrated in <FIG>, may be provided in addition thereto. With this, the number of components of the reflow apparatus <NUM> can be reduced. The gas supply apparatus <NUM> is configured to supply the inert gas such as nitrogen (corresponding to the example of the first gas) into the sealed space S1. The gas supply apparatus <NUM> includes a gas source, and supplies the gas into the sealed space S1 through a supply pipe 32a In the example illustrated in <FIG>, a part of the supply pipe 32a is located in the sealed space S1 through the fourth seal <NUM>. Note that, the gas to be supplied by the gas supply apparatus <NUM> is not limited to the inert gas, and may be an arbitrary gas. However, in order that influence on an environment in the processing chamber 110D is suppressed even in a case where the gas filling the sealed space S1 leaks into the processing chamber 110D, the gas is desirably the inert gas such as nitrogen.

The measuring apparatus <NUM> measures pressure or concentration of the gas in the sealed space S1. The measuring apparatus <NUM> may be, for example, a pressure sensor that measures the pressure in the sealed space S1. Alternatively, the measuring apparatus <NUM> may be, for example, a gas concentration sensor that measures the concentration of the gas such as oxygen (corresponding to the example of the secondary gas). As the oxygen concentration sensor, for example, there may be employed an EcoaZ EZY series manufactured by Daiichinekken Co. In the example illustrated in <FIG>, the measuring apparatus <NUM> is arranged on an outside of the sealed space S1, and a communication pipe 30a that is connected to the measuring apparatus <NUM> extends into the sealed space S1 through the fourth seal <NUM>. The measuring apparatus <NUM> is configured to be capable of measuring the concentration of the gas in the sealed space S1 by sucking the gas through the communication pipe 30a, and of transmitting measurement data, for example, to the control apparatus <NUM>.

As illustrated in <FIG>, the fourth seal <NUM> includes a piping hole 44a through which the communication pipe 30a that is connected to the measuring apparatus <NUM> passes, and a piping hole 44b through which the supply pipe 32a from the gas supply apparatus <NUM> passes. The piping hole 44a has a diameter slightly smaller than a diameter of the communication pipe 30a such that the gas in the sealed space S1 can be suppressed from leaking through between the communication pipe 30a and the piping hole 44a. Similarly, the piping hole 44b has a diameter slightly smaller than a diameter of the supply pipe 32a from the gas supply apparatus <NUM> such that the gas in the sealed space S1 can be suppressed from leaking through between the supply pipe 32a and the piping hole 44b. Note that, the fourth seal <NUM> need not necessarily include the piping hole 44a or the piping hole 44b. In that case, both the communication pipe 30a and the supply pipe 32a may be arranged to extend between the fourth seal <NUM> and the first seal <NUM>, the second seal <NUM>, the third seal <NUM>, or the fixation portion <NUM>. When the furnace body <NUM> is closed, the first seal <NUM>, the second seal <NUM>, the third seal <NUM>, and the fourth seal <NUM> are compressed and deformed. With this, gaps between the communication pipe 30a and the supply pipe 32a and the gasket <NUM> are closed. As a result, the leakage of the gas in the sealed space S1 can be suppressed. Alternatively, both the communication pipe 30a and the supply pipe 32a may be arranged to extend through any of the first seal <NUM>, the second seal <NUM>, the third seal <NUM>, and the fixation portion <NUM>. In other words, as long as the communication pipe 30a and the supply pipe 32a can be connected to an inside of the sealed space S1 while maintaining the sealed state, the communication pipe 30a and the supply pipe 32a may be arbitrarily located. Note that, the measuring apparatus <NUM> may be arranged in the sealed space S1.

Note that, by fitting the push rivet <NUM> rigidly into the through-hole 16a, the gas in the sealed space S1 can be prevented from leaking through the through-hole 16a formed in the fixation portion <NUM>.

Now, a method of detecting the failures of the gasket <NUM> is described. <FIG> is a flowchart showing the method of detecting the failures of the gasket <NUM> in the reflow apparatus <NUM> according to this embodiment. <FIG> shows the example in which the measuring apparatus <NUM> is the pressure sensor. First, the furnace body <NUM> is closed (Step S801). With this, the sealed space S1 isolated from the processing chamber 110D of the furnace body <NUM> is defined by the furnace body <NUM> and the gasket <NUM>. Then, the gas supply apparatus <NUM> injects the inert gas such as nitrogen into the sealed space S1 through the supply pipe 32a (Step S802). The inert gas may be injected by a predetermined injection amount into the sealed space S1. When the measuring apparatus <NUM> is the pressure sensor, the inert gas may be injected to cause the pressure in the sealed space S1 to reach predetermined pressure.

After the inert gas has been supplied into the sealed space S1, the measuring apparatus <NUM> measures the pressure in the sealed space S1 via the communication pipe 30a at an arbitrary timing (Step S803). The measurement data obtained by the measuring apparatus <NUM> is transmitted, for example, to the control apparatus <NUM>. Alternatively, the measurement data may be transmitted to the external computer other than the control apparatus <NUM>.

Next, after a predetermined time period has elapsed since the injection of the inert gas from the gas supply apparatus <NUM>, it is determined whether or not the pressure measured by the measuring apparatus <NUM> has reached a predetermined threshold (Step S804). Specifically, the control apparatus <NUM> compares a value of the pressure measured by the measuring apparatus <NUM> to the predetermined threshold, and determines whether or not the value of the measured pressure has increased to this threshold. If it is determined that the value of the pressure has not reached the threshold even after the predetermined time period has elapsed (No in Step S804), it is estimated that the gas in the sealed space S1 has leaked to the outside of the sealed space S1.

When the control apparatus <NUM> includes a display capable of displaying the value measured by the measuring apparatus <NUM>, this measured value may be displayed on the display. In this case, the operator may check the value displayed on the display, and the operator may determine whether or not this value has reached the predetermined threshold.

If the measuring apparatus <NUM> determines that the pressure has not reached the predetermined threshold even after the predetermined time period has elapsed (No in Step S804), the control apparatus <NUM> causes a notification apparatus (not shown) provided to the reflow apparatus <NUM> to notify the operator that the failures of the gasket <NUM> have occurred (Step S805). This notification apparatus may be, for example, a display apparatus that is provided to the control apparatus <NUM> and that displays the failures, or an alarm apparatus that notifies the operator of the failures by sound or vibration. Note that, if the operator determines whether or not the measured value displayed on the display has reached the predetermined threshold in Step S804, Step S805 may be omitted. Meanwhile, if it is determined that the value of the pressure has reached the threshold, that is, the value of the pressure has increased to the threshold (Yes in Step S804), it is determined that the failures of the gasket <NUM> have not occurred, and the processes of Step S803 and Step S804 are repeated.

<FIG> is a flowchart showing another method of detecting the failures of the gasket <NUM> in the reflow apparatus <NUM> according to this embodiment. <FIG> shows the example in which the measuring apparatus <NUM> is the gas concentration sensor. In <FIG>, the same processes as those shown in <FIG> are denoted by the same reference symbols to omit redundant description thereof.

After the inert gas has been supplied into the sealed space S1 in Step S802, the measuring apparatus <NUM> measures concentration of a certain gas in the sealed space S1 via the communication pipe 30a at an arbitrary timing (Step S903). Specifically, when the measuring apparatus <NUM> is the oxygen concentration sensor, the measuring apparatus <NUM> measures oxygen concentration in the sealed space S1. The measurement data obtained by the measuring apparatus <NUM> is transmitted, for example, to the control apparatus <NUM>. Alternatively, the measurement data may be transmitted to the external computer other than the control apparatus <NUM>.

Next, after a predetermined time period has elapsed since the injection of the inert gas from the gas supply apparatus <NUM>, it is determined whether or not the gas concentration measured by the measuring apparatus <NUM> has reached a predetermined threshold (Step S904). Specifically, when the measuring apparatus <NUM> is the oxygen concentration sensor, the control apparatus <NUM> compares a value of the oxygen concentration measured by the measuring apparatus <NUM> to the predetermined threshold, and determines whether or not the value of the oxygen concentration has reached this threshold. If it is determined that the value of the oxygen concentration has not reached the threshold (No in Step S904), the processes of Step S903 and Step S904 are repeated. Meanwhile, if it is determined that the value of the oxygen concentration has reached the threshold, that is, the value of the oxygen concentration has increased to the threshold (Yes in Step S904), it is estimated that the oxygen concentration has increased due to ingress of oxygen from the outside of the sealed space S1 into the sealed space S1.

Alternatively, the measuring apparatus <NUM> may be a sensor that measures a gas of the same type as that of the gas to be injected into the sealed space S1 by the gas supply apparatus <NUM> (corresponding to an example of a second gas). Specifically, for example, when the gas supply apparatus <NUM> supplies nitrogen into the sealed space S1, the measuring apparatus <NUM> may be a nitrogen concentration sensor. In this case, the control apparatus <NUM> compares a value of nitrogen concentration measured by the measuring apparatus <NUM> to a predetermined threshold, and determines whether or not the value of the nitrogen concentration has reached this threshold. If it is determined that the value of the nitrogen concentration has not reached the threshold (No in Step S904), the processes of Step S903 and Step S904 are repeated. Meanwhile, if it is determined that the value of the nitrogen concentration has reached the threshold, that is, the value of the nitrogen concentration has decreased to the threshold (Yes in Step S904), it is estimated that nitrogen in the sealed space S1 has leaked to the outside of the sealed space S1.

If the measuring apparatus <NUM> determines that the gas concentration has reached the predetermined threshold (Yes in Step S904), the control apparatus <NUM> causes the notification apparatus (not shown) provided to the reflow apparatus <NUM> to notify the operator that the failures of the gasket <NUM> have occurred (Step S805).

Next, another example of the gasket <NUM> according to this embodiment is described. <FIG> is a top view illustrating the other example of the gasket <NUM> according to this embodiment. The gasket <NUM> illustrated in <FIG> is different from the gasket <NUM> illustrated in <FIG> in further including a fifth seal <NUM>, a sixth seal <NUM>, and a seventh seal <NUM> that effect the sealing between the first seal <NUM> and the second seal <NUM>. Note that, although not shown, still other seals that effect the sealing between the first seal <NUM> and the second seal <NUM> may be provided. The third seal <NUM>, the fourth seal <NUM>, the fifth seal <NUM>, the sixth seal <NUM>, and the seventh seal <NUM> are away from each other.

The third seal <NUM>, the fourth seal <NUM>, the fifth seal <NUM>, the sixth seal <NUM>, and the seventh seal <NUM> of the gasket <NUM> illustrated in <FIG> effect the sealing between the first seal <NUM> and the second seal <NUM>. With this, when the furnace body <NUM> is closed, a plurality of sealed spaces S2, S3, S4, and S5 are defined by the furnace body <NUM> and the gasket <NUM>. In other words, the sealed space S1 that is formed by the gasket <NUM> illustrated in <FIG> is divided by the fifth seal <NUM>, the sixth seal <NUM>, and the seventh seal <NUM> of the gasket <NUM> illustrated in <FIG>.

As illustrated in <FIG>, the communication pipe 30a and the supply pipe 32a are connected to an inside of each of the sealed spaces S2, S3, S4, and S5. In the illustrated example, in the sealed space S2, the communication pipe 30a and the supply pipe 32a are connected to the inside of the sealed space S2 through the fourth seal <NUM>. In the sealed spaces S3, S4, and S5, the communication pipe 30a and the supply pipe 32a are connected to the inside of each of the sealed spaces S3, S4, and S5 through the fixation portion <NUM>. As long as the communication pipe 30a and the supply pipe 32a communicate with the inside of each of the sealed spaces S2, S3, S4, and S5, positions of these pipes are not limited. The respective communication pipes 30a may be connected to the single measuring apparatus <NUM>, or may be connected respectively to independent measuring apparatuses <NUM>. The respective supply pipes 32a may be connected to the single measuring apparatus <NUM>, or may be connected respectively to independent gas supply apparatuses <NUM>. The inert gas such as nitrogen may be supplied from the gas supply apparatus <NUM> into the sealed spaces S2, S3, S4, and S5 respectively through the supply pipes 32a. In addition, pressure or concentration of the gas in the sealed spaces S2, S3, S4, and S5 may be measured by the measuring apparatus <NUM> respectively via the communication pipes 30a.

In the example illustrated in <FIG>, the pressure or the concentration of the gas in the sealed spaces S2, S3, S4, and S5 are measured by the measuring apparatus <NUM>. With this, which part of the first seal <NUM> and the second seal <NUM> in the transport direction of the boards is damaged can be detected. Specifically, for example, in a case where the measuring apparatus <NUM> detects abnormalities of the pressure or the concentration of the gas in the sealed space S3, it can be determined that, of parts of the first seal <NUM> or the second seal <NUM>, ones defining the sealed space S3 have been damaged.

As described above, in the reflow apparatus <NUM> according to this embodiment, the pressure or the concentration of the gas in the sealed space S1 can be measured after the sealed space S1 has been filled with the inert gas such as nitrogen. Thus, in a case where the pressure or the concentration of the gas in the sealed space S1 reaches a predetermined threshold, it can be grasped that the failures of the gasket <NUM> have occurred. Further, the sealed space S1 that is defined by the gasket <NUM> is located to separate the processing chamber 110D and the outside of the furnace, and in addition, can be more easily reduced in volume than the processing chamber 110D. Thus, unlike the related art, leakage of the gas from the sealed space S1 that is narrower than the processing chamber 110D can be detected before occurrence of abnormalities of the concentration of the gas such as oxygen in the processing chamber 110D. As a result, the failures of the gasket <NUM> can be more promptly detected.

In addition, in the reflow apparatus <NUM> according to this embodiment, whether or not abnormalities of oxygen concentration in the processing chamber 110D have occurred can be monitored by the measuring apparatus <NUM> illustrated in <FIG>, and the failures of the gasket <NUM> can be monitored by the measuring apparatus <NUM> illustrated in <FIG> and <FIG>. With this, by monitoring whether or not the failures of the gasket <NUM> have occurred in a case where the abnormalities of the oxygen concentration in the processing chamber 110D are detected, it can be determined whether or not the abnormalities of the oxygen concentration in the processing chamber 110D are caused by the gasket <NUM>. Thus, if the failures of the gasket <NUM> have not occurred, it can be determined that the abnormalities of the oxygen concentration in the processing chamber 110D are caused by other factors. Therefore, causes of the abnormalities of the oxygen concentration can be easily specified.

Although the upper furnace body 110A is openable/closable on its one side relative to the lower furnace body 110B in the above-described configuration of the reflow apparatus <NUM> according to this embodiment, the present invention is not limited to this configuration. For example, the configuration of the present invention is applicable, for example, also to a soldering apparatus as disclosed in <CIT>, in which the upper furnace body 110A is opened and closed by being moved upward and downward by raising/lowering means. In addition, the present invention is applicable also to a soldering apparatus including two or more transport conveyors.

Claim 1:
A soldering apparatus (<NUM>), comprising:
a furnace body (<NUM>) including a processing chamber (110D) in which boards are processed;
a gasket (<NUM>)
provided at least to a part of the furnace body (<NUM>), and configured to seal the furnace body (<NUM>);
characterised in that:
the gasket (<NUM>) includes
a first seal (<NUM>),
a second seal (<NUM>) that is arranged away from the first seal (<NUM>),
a third seal (<NUM>) that effects sealing between the first seal (<NUM>) and the second seal (<NUM>), and
a fourth seal (<NUM>) that effects the sealing between the first seal (<NUM>) and the second seal (<NUM>) and that is arranged away from the third seal (<NUM>), and
a sealed space (S1, S2, S3, S4, S5)
isolated and distinct from the processing chamber (110D) to serve as an independent space, and
defined by the furnace body (<NUM>) and the gasket (<NUM>);
and, in that the sealed space (S1, S2, S3, S4, S5) is defined at least by the furnace body (<NUM>),
the first seal (<NUM>),
the second seal (<NUM>),
the third seal (<NUM>), and
the fourth seal (<NUM>),
and being further characterised by:
a gas supply apparatus (<NUM>) configured to supply a first gas into the sealed space (S1, S2, S3, S4, S5);
a measuring apparatus (<NUM>) configured to measure one of
pressure in the sealed space (S1, S2, S3, S4, S5) and
concentration of a second gas in the sealed space (S1, S2, S3, S4, S5); and
a control apparatus (<NUM>) capable of communicating with the measuring apparatus (<NUM>),
wherein the control apparatus (<NUM>) is configured to determine whether or not the one of the pressure and the concentration received from the measuring apparatus (<NUM>) has reached a predetermined threshold.