JPH0235406Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a vapor phase soldering device having a liquid circulation system.

(Prior Art) A conventional vapor phase soldering apparatus uses a heater 14 to pump a liquid 13 contained in a liquid tank 12 provided integrally at the bottom of a steam tank 11, as shown in FIG. A vapor phase 15 is formed in the steam tank 11 by evaporation.
Printed wiring board 1 as an object to be soldered
7 is carried in, reflow soldering of the components mounted on the board is performed using the vaporization latent heat of the vapor phase 15, and the board 17 is carried out to the outside through the carrying out port 18 provided on the other side of the steam tank 11. In this case, the vapor phase 15 is prevented from being carried out to the outside by the condensing action of a cooling coil 19 inside the carry-in port 16 and the carry-out port 18, but the cooling coil 19 alone is not enough. This prevention of steam leakage is not perfect.

Therefore, the carry-in port 16 and the carry-out port 18
Steam is sucked into the condensation tank 23 from near the opening of the liquid recovery device 21 through the suction pipe 22, and the air is forcibly exhausted to the outside by a fan through the condenser 24 and exhaust pipe 25 of the refrigeration cycle. The liquid 13a condensed in the vessel 24 and accumulated in the condensation tank 23 is circulated to the liquid tank 12 via a liquid return pipe 28 by a pump 27.

(Problems to be solved by the invention) In the liquid recovery device 21 described above, steam containing moisture is condensed, and the liquid 13 is contained in the condensation tank 23.
Water accumulates along with a, and this water-containing liquid 13
If a is returned into the liquid tank 12, there is a problem in that it has a negative effect on the formation of the vapor phase 15.

The purpose of the invention is to remove water in the vapor phase circulation system so that it does not adversely affect the formation of the vapor phase.

[Structure of the idea]

(Means for Solving the Problems) The present invention evaporates the liquid 33 in the liquid tank 32 to form a vapor phase 35 in the vapor tank 31.
Objects to be soldered 37 are carried in through a loading port 36 provided on one side of the steam tank 31, and reflow soldering is performed using the latent heat of vaporization of the vapor phase 35. In a vapor phase soldering apparatus in which the soldering object 37 is carried out to the outside through a carry-out port 38 provided in the transfer port 38, the suction pipe 4 is
2 into the condensation tank 43, and the liquid 33a accumulated in the condensation tank 43 is sent to the liquid tank 3 via the liquid return pipe 48 by the pump 47.
2, a liquid return port 57 connected to the liquid return pipe 48 is provided at the bottom of the condensation tank 43 of the liquid recovery device 41, and a drain port 5 is provided at a predetermined level position of the condensation tank 43.
8, and a liquid level detection device 59 for detecting the liquid level accumulated in the condensing tank 43 and operating the pump 47.

(Function) According to the present invention, when a certain amount or more of the condensed liquid 33a accumulates in the condensation tank 43 of the liquid recovery device 41, the liquid level detection device 59 detects this and operates the pump 47 to collect a certain amount of the liquid 33a. The water 60 is returned to the steam tank 31, and the water 60 condensed together with the liquid 33a accumulates above the liquid 33a due to the difference in specific gravity, and is automatically discharged from the drain port 58 when the amount exceeds a predetermined amount.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a liquid tank 32 is integrally provided at the bottom of the steam tank 31, and this liquid tank 32 contains a special liquid (fluorinated inert solvent, etc.) with a boiling point of 215°C.
Product name: Florinat) 33 is stored.
The liquid 33 is evaporated by a heater 34 inserted into the liquid, and a vapor phase 35 is formed inside the steam tank 31.

A loading port 36 is provided on one side of the steam tank 31 with respect to the steam phase 35 formed in the steam tank 31.
Printed wiring board 3 as an object to be soldered
7 is carried in, reflow soldering is performed by the latent heat of vaporization possessed by the vapor phase 35, and the board 37 is carried out to the outside through an outlet 38 provided on the other side of the steam tank 31. Cooling coils 3 for condensing the vapor phase 35 at the carry-in port 36, the carry-out port 38, and the upper part of the steam tank 11
9 is provided. This cooling coil 39 is a coiled (helical) cooling water pipe. 37a is a conveyor for conveying the printed wiring board 37.

At the inlet port 36 and the outlet port 38, the vapor phase 35 is prevented from leaking to the outside by the condensing action of the cooling coil 39 therein. Since leakage prevention is not perfect, a liquid recovery device 41 is provided that forcibly recovers steam from the vicinity of the openings of the carry-in port 36 and the carry-out port 38, condenses it, and returns the liquid to the liquid tank 32.

This liquid recovery device 41 has a suction pipe 42 pulled out from near the openings of the carry-in port 36 and the carry-out port 38 and connected to a condensation tank 43, and a condensation coil (refrigeration cycle evaporator) connected to the condensation tank 43. ) 44, an exhaust pipe 45 is drawn out from the upper part of this condensing coil 44, an exhaust fan is provided in this exhaust pipe 45, and the suction port of a circulation pump 47 is connected to the lower part of the tank 43. A liquid return pipe 48 drawn out from the discharge port is connected to the vicinity of the openings on the bottom surfaces of the carrying-in port 36 and the carrying-out port 38.

By separating the connection part of the liquid return pipe 48 and the liquid tank 32 in this way, a preheating section is provided at the bottom of the inlet part 36 and the outlet part 38 as part of the liquid circulation system. A section 49 is provided.

Further, as shown in FIG. 2, the liquid recovery device 4
One condensation tank 43 is provided with a partition wall 51 inside to partition a condensation chamber 52 and a recovery chamber 53.
A suction port 54 to which the suction pipe 42 is connected is provided on both upper sides of the condensing chamber 52, and
An exhaust port 55 to which the exhaust pipe 45 is connected to the upper center
will be established. Further, a communication pipe 56 is provided between the condensation chamber 52 and the recovery chamber 53, with one end opening to the inner bottom of the condensation chamber 52 and the other end opening to the middle part of the recovery chamber 53. A liquid return port 57 is provided at the bottom of the recovery chamber 53 to which the liquid return pipe 48 is connected via a pump 47, and the condensation chamber 52 is located at a predetermined level higher than the opening of the communication pipe 56 to the recovery chamber 53. A drain port 58 is provided in the drain port 58.

Further, a liquid level detection device 59 is provided that detects the liquid level accumulated in the recovery chamber 53 of the condensation tank 43 and operates the pump 47.

Then, the printed wiring board 37 is inserted into the loading port 3.
6 and into the steam tank 31, the latent heat of vaporization (215° C.) of the vapor phase 35 generated by evaporation from the liquid 33 by the heater 34 causes the substrate 37 to be placed between the substrate 37 and the components mounted on the substrate. The cream solder is melted, the mounting components are soldered to the surface of the board 37, and the molten solder is solidified at the stage when the board 37 is continuously carried out to the outside through the outlet 38.

Along with this, the loading port 36 and the loading port 3
Steam is sucked into the condensing chamber 52 of the condensing tank 43 from near the opening of 8 through the suction pipe 42, and the air is forcibly exhausted to the outside through the condensing coil 44 and the exhaust port 55 through the exhaust pipe 45,
Further, the vapor is condensed by the condensing coil 44 and collected as a liquid 33a at the bottom of the condensing chamber 52. On this occasion,
Moisture contained in the steam is also condensed and accumulated as water 60, but the difference in specific gravity between the liquid 33a and the water 60 (2:
1), the liquid 33a accumulates below and the water 60 accumulates above. When the water 60 reaches a predetermined level or higher, it is automatically discharged from the drain port 58.

On the other hand, the liquid 33a accumulated in the condensation chamber 52 is guided into the recovery chamber 53 through the communication pipe 56. When a certain amount or more of the liquid 33a accumulates in the recovery chamber 53, the liquid level detection device 59 detects this and operates the pump 47 to send a certain amount of the liquid 33a from the liquid return port 57 at the bottom to the liquid return pipe 48. It is supplied onto the bottom surfaces near the openings of the carry-in port 36 and the carry-out port 38.

At the stage where this liquid flows down on the sloped bottom surfaces of the loading inlet part 36 and the unloading outlet part 38, its temperature is raised in the preheating section 49 heated by conductive heat from the heater 34, and is heated to a high temperature to form a liquid tank. 32 cycles. In this way, the loading port 36 and the loading port 3
The bottom surface of 8 applies heat to the low-temperature liquid supplied from the liquid return pipe 48 to raise its temperature, but on the other hand, the temperature does not rise to the extent that heat is taken away by the return liquid and the liquid evaporates.

Next, another embodiment will be described with reference to FIGS. 3 and 4.

In this embodiment, the condensation tank 4 of the liquid recovery device 41
A liquid return port 57 for connecting the liquid return pipe 48 is provided at the bottom of the condensation tank 43 without providing a partition wall in the condensation tank 43, and a drain port 58 is provided at a predetermined level position of the condensation tank 43. A float type liquid level detection device 59 is provided inside.

This liquid level detection device 59 is provided with a reed switch 62 for operating the pump 47 in an upright guide pipe 61, a float 63 that is movable up and down on the outside of the guide pipe 61, and A magnet 64 is provided for actuating the switch 62. In addition, the float 63
For example, the specific gravity is set to 1.5 so that it floats in the liquid 33a but sinks in the water 60.

Then, the liquid 33a and water 6 are added to the condensation tank 43.
When the water 60 reaches a predetermined level or higher, it is automatically discharged from the drain port 58, and when a certain amount of liquid 33a has accumulated, the float 63 floats to that level. The magnet 64 operates the reed switch 62, drives the pump 47, and sends out a certain amount of liquid 33a from the liquid return port 57 at the bottom.

[Effect of idea]

According to the present invention, when a certain amount of condensed liquid accumulates in the condensation tank of the liquid recovery device, the liquid level detection device detects this and operates the pump to return a certain amount of liquid to the steam tank. The water condensed with the liquid accumulates above the liquid due to the difference in specific gravity, and when it exceeds a predetermined amount, it is automatically drained from the drain port.
Moisture does not adversely affect the vapor phase formed in the steam tank, and a stable vapor phase can always be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the vapor phase soldering device of the present invention, Fig. 2 is a sectional view of its liquid recovery device, and Fig. 3 is a sectional view showing another embodiment of the liquid recovery device. , Figure 4 is a cross-sectional view of the liquid level detection device, and Figure 5 is a cross-sectional view of the liquid level detection device.
The figure is a sectional view of a conventional vapor phase soldering device. 31...Steam tank, 32...Liquid tank, 33, 33a
...liquid, 35 ... vapor phase, 36 ... carry-in port, 3
7...Soldering object, 38...Export port, 41
...liquid recovery device, 42 ... suction pipe, 43 ... condensation tank, 47 ... pump, 48 ... liquid return pipe, 5
7...Liquid return port, 58...Drain port, 59...Liquid level detection device.

Claims (1)

[Claims for Utility Model Registration] The liquid in the liquid tank is evaporated to form a vapor phase in the vapor tank, and the soldered material is connected to the vapor phase from an inlet provided on one side of the vapor tank. In a vapor phase soldering device, in which an object is carried in, reflow soldering is performed using the vaporization latent heat of the vapor phase, and the object to be soldered is carried out to the outside through an outlet provided on the other side of the steam tank. , a liquid recovery device that sucks vapor into the condensation tank from the carry-in port and the carry-out port through the suction pipe, and supplies the liquid accumulated in the condensation tank to the liquid tank via the liquid return pipe using a pump; A liquid return port connected to the liquid return pipe is provided at the bottom of the condensation tank of this liquid recovery device, and a drain port is provided at a predetermined level position of the condensation tank, and the liquid level accumulated in the condensation tank is 1. A vapor phase soldering apparatus comprising a liquid level detection device that detects the liquid level and operates the pump.