JPH0798524B2 - Method for manufacturing vacuum powder insulation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a vacuum powder heat insulating body used in a refrigerator or the like.

"Prior Art" Conventionally, vacuum heat insulating materials have been provided as having heat insulating performance far superior to that of plastic foam insulating materials. An example of a conventional vacuum heat insulating material of this type
Shown in the figure. The vacuum heat insulating material shown in this figure is disclosed in JP-A-58-58.
This is described in Japanese Patent No. 145678. Reference numeral 1 in this figure
Is a vacuum heat insulating material, and 2 is an inorganic foamed powder such as pearlite (hereinafter abbreviated as powder). This vacuum heat insulating material 1 is obtained by filling powder 2 into an air-permeable middle bag 3 such as a paper bag, and adhering the end face 4 of the opening with a tape, an adhesive 5, etc. It is inserted into the outer bag 6 made of a film bag such as the laminate, vacuum deaerated, and then sealed. The inside of the outer bag 6 is kept in a vacuum state of about 1 Torr. As a vacuum insulation material for products, the insulation performance is guaranteed unless the degree of vacuum deteriorates.
Permeation of a very small amount of gas cannot be avoided through the plastic film of the outer bag 6. For this reason, as a countermeasure, adsorbents such as synthetic zeolite and activated carbon are usually added based on calculations that take into account the years of warranty and environmental conditions.

The vacuum heat insulating material 1 is manufactured as shown in FIGS. 4 to 8. First, the powder 2 is filled in the inner bag 3 (FIG. 4), and the molding and heat drying are performed (FIG. 5).
Place in outer bag 6 (Fig. 6). Then, a small bag 3a made of a breathable material containing an adsorbent is placed in the outer bag 6 as shown in FIG. Then, this is fixed in the champer 8 of the vacuum packaging machine 7 shown in FIG. 8, and the end face 9 of the opening of the outer bag 6 is placed on the fusion plate 11 of the heat sealing machine 10 in the chamber 8 for vacuum deaeration. To do. After degassing the chamber 8 to 1 Torr,
The heat sealing machine 10 is operated and the end surface 9 of the opening of the outer bag 6 is heat sealed.

[Problems to be Solved by the Invention] In the manufacturing method described above, the outer bag 6 is evacuated after the outer bag 6 is filled with the powder 2 and the adsorbent 2a under atmospheric pressure. Therefore, if the powder 2 or the adsorbent 2a is directly filled in the outer bag 6, the fine particles of the powder 2 or the adsorbent 2a will be scattered during vacuum evacuation and adhere to the opening end surface 9 of the outer bag 6, or even the chamber. At the time of deaeration in 8, the fine powder is entrained together with the air, and when the outer bag 6 is heat-sealed, the fine powder is caught in the hermetically sealed portion to cause a defect that the vacuum state cannot be maintained, or vacuum exhaust is performed. The powder particles are sucked into the suction port of the pump P, resulting in poor exhaust. Therefore, in the manufacturing method as described above, the powder 2 and the adsorbent are used.
By filling 2a in the air-permeable inner bag 3 or the small bag 3a in advance and then packing it in the outer bag, it is possible to prevent the powder particles from being sucked or scattered during vacuum evacuation. That is, the inner bag 3 and the small bag 3a have a role as a medium for handling the powder as a part and a role as a powder filter during vacuum deaeration.

However, the vacuum heat insulating material using the middle bag 3 and the small bag 3a has the following problems.

． In addition to the high material cost of the middle bag 3 and the small bag 3a, the packaging process is complicated and the manufacturing cost is high. As a result, the vacuum heat insulating material cannot be reduced in cost.

． When the middle bag 3 and the small bag 3a are packed in the outer bag 6 and then deaerated, not only the exhaust efficiency is poor due to the ventilation resistance of the middle bag 3 and the small bag 3a, but it takes a long time to exhaust the vacuum. It was difficult.

． When inserting the inner bag 3 into the outer bag 6, 10 to 30 in the width direction
mm, the clearance of 70 to 130 mm is required in the length direction including the adsorbent part, so the area ratio of the effective heat insulating part to the total projected area is as small as 50 to 70% at the time of being a product, and as a heat insulating material The effect of.

． In the process of inserting the powder and the adsorbent into the outer bag 6 after the heating and drying treatment, the quality of the product varies due to the influence of atmospheric components such as moisture.

It is an object of the present invention to solve the above problems and provide a manufacturing method capable of easily manufacturing a high-performance vacuum powder heat insulating body.

"Means for Solving Problems" A method for manufacturing a vacuum powder heat insulating body according to the present invention is to supply a filler powder into a vacuum cyclone for deaeration, and then sequentially transfer it to a plurality of vacuum hoppers. After degassing one or more times, the powder kept under reduced pressure is then fed into a vacuum chamber under vacuum conditions, where it is placed in a package made of gas impermeable material. It is characterized by filling and sealing.

Hereinafter, the present invention will be described in detail with reference to the drawings. First
FIG. 1 is a diagram showing an example of an apparatus suitable for carrying out the present invention. In this device, first, the hopper opened under atmospheric pressure.
The powder 2 that has been heat-dried at 150 ° C. or higher is continuously fed into the inside of 12. By alternately switching the two valves 13 and 14 provided on the delivery side of the hopper 12, the powder 2 in the hopper 12 is supplied into the vacuum cyclone 15. This vacuum cyclone 15 is a pump (water ring pump) 16
The powder 2 supplied into the vacuum cyclone 15 moves on the inner wall of the vacuum cyclone 15 while being degassed, and during this movement, the pump (water seal pump) 16 exhausts the powder 2 in a short time. Efficiently degassed to a specified vacuum level,
The vacuum cyclone 15 is dropped into a first vacuum hopper 17 having a vacuum degree substantially the same as that of the vacuum cyclone 15. Most of the air and water contained in the powder 2 are separated from the powder 2 in the vacuum cyclone 15, and are exhausted from the upper part of the vacuum cyclone 15 by a pump (water seal pump) 16. The powder 2 dropped in the first vacuum hopper 17 is accumulated in the lower part of the vacuum hopper 17. The powder 2 accumulated in the first vacuum hopper 17 is transferred through the rotary valve 18 into the second vacuum hopper 19 which is evacuated to a higher degree than the powder 2 and is accumulated in the lower portion thereof. The inside of the second vacuum hopper 19 is evacuated by a pump (water-sealing pump and mechanical booster pump) 21, and the powder 2 accumulated in the lower portion of the second vacuum hopper 19 is released to a predetermined vacuum degree. Be worried. At this time, the first vacuum hopper 17 and the second vacuum hopper 19 are arranged such that the ventilation resistance of the powder 2 accumulated in the first vacuum hopper 17 and the ventilation resistance between the impeller and the caging inside the rotary valve 18 are increased. The pressure difference can be maintained by and. The powder 2 accumulated in the second vacuum hopper 19 is
It is fed through the rotary valve 22 into a vacuum chamber 23 that has been evacuated to a higher degree than this. Although not shown in the vacuum chamber 23, a bag of vacuum powder insulation, a filling machine for filling the powder 2 and a plurality of adsorbents in the bag, and a sealing for sealing the bag are provided. Sealing machine,
And a molding device for molding the vacuum powder heat insulator into a flat plate shape. Further, the vacuum chamber 23 is filled with the powder 2 in the vacuum powder heat insulating body and supplies a gas adsorbent such as activated carbon or molecular sieve for the purpose of adsorbing the gas in the vacuum powder heat insulating body and maintaining a high degree of vacuum. Vacuum hoppers 24, 25 are connected. These adsorbents are used by switching and using two valves 26, 27, 28, 29 arranged on the delivery side of each vacuum hopper 24, 25.
It can be fed to the filling machine in the vacuum chamber 23. Since the vacuum hoppers 24 and 25 for supplying the adsorbent have a small capacity, they are sufficiently evacuated in a batch manner. The inside of the vacuum chamber 23 is evacuated by the pumps (mechanical booster pumps) 30, 31 and the pumps (oil rotary pumps) 32, 33 so as to have a vacuum degree similar to a predetermined vacuum degree in the vacuum powder insulation body. ing. The second vacuum hopper 19 and the vacuum chamber 23 maintain a pressure difference by the ventilation resistance of the powder 2 accumulated in the second vacuum hopper 19 and the ventilation resistance between the impeller and the caging inside the rotary valve 22. can do. The powder 2 supplied into the vacuum chamber 23 is degassed to a predetermined degree of vacuum before being metered and filled by a metering and filling machine, and then filled with the above-mentioned adsorbent into the bag of the vacuum powder heat insulator. Then, the opening of the bag is hermetically sealed.

Incidentally, the vacuum chamber 23, by supplying a packaging material under atmospheric pressure conditions, and by attaching a packaging material supply mechanism and a product takeout mechanism having a function of taking out the vacuum powder insulation of the product under atmospheric pressure conditions, Vacuum powder insulation can be continuously produced.

The vacuum powder heat insulator manufactured by this manufacturing apparatus has a structure as shown in FIG. The vacuum powder insulation 34 shown in this figure comprises a powder 2 and an adsorbent such as activated carbon or molecular sieve directly in a packaging bag 35 made of a gas impermeable material such as a laminated film of metal and plastics. The inner bag 3 filled with the filling material 36 and sealed, and used in the conventional vacuum heat insulating material 1 shown in FIG.
Has been omitted.

The method for producing a vacuum powder heat insulating body of the present invention comprises degassing a part or all of the filler powder, filling the inside of a bag in a vacuum chamber under vacuum conditions, and sealing the inside of the bag. Even if the bag is not used, it is possible to maintain the vacuum of the vacuum powder insulator in a normal vacuum state, and the degassing process of this powder is gradually degassed while being sequentially transferred to the vacuum cyclone and multiple vacuum hoppers. Since the treatment is performed, this degassing treatment can be performed efficiently.

That is, when the deaerated powder is fed into a vacuum chamber kept at a predetermined vacuum degree and the bag is filled with the degassed powder, the vacuum degree in which the fine particles of the powder hardly scatter in the vacuum chamber ( Since it is about 1 Torr), the fine particles of the powder are not scattered during the powder filling, and the fine particles of the powder do not get caught in the hermetically sealed portion of the packaging bag, which does not cause a defect that the vacuum in the packaging bag cannot be maintained. Therefore, it becomes possible to directly fill powder in a bag made of gas impermeable material and to hermetically seal it, and it is possible to omit the middle bag that was required for conventional vacuum heat insulating materials. It is possible to solve problems such as an increase in cost and a decrease in degassing efficiency caused by the use of the inner bag.

Further, the powder 2 filled in the vacuum powder heat insulator is degassed stepwise from atmospheric pressure conditions to a vacuum degree of about 10 ^-1 to ^-2 by a vacuum cyclone and a plurality of vacuum hoppers. A mechanical booster pump and a rotary pump are used in combination for a portion that needs to be evacuated, and a water-sealed pump is used for the first deaeration. The powder can be degassed.

Next, examples of the present invention will be described.

"Embodiment" In the apparatus suitable for carrying out the present invention shown in FIG.
It operated according to the following operating conditions.

Filler: Silica fine powder Adsorbent: Activated carbon, molecular sieve Packaging material: Aluminum vapor-deposited laminated film Vacuum degree in product packaging 10 ^-1 Torr Vacuum degree in first vacuum hopper 50 Torr Vacuum in second hopper Degree ... 3 Torr Vacuum degree in vacuum chamber ... 0.1 Torr As a result, the vacuum powder heat insulator having the structure shown in FIG. 2 could be continuously manufactured.

The vacuum pumps used at this time are shown in the table below.

"Effects of the Invention" As described above, in the method for manufacturing a vacuum powder heat insulating body of the present invention, a degassed filler powder is filled and sealed in a bag in a vacuum chamber under vacuum conditions. Therefore, normal sealing can be performed without using the inner bag.
Therefore, the material cost of the inner bag itself can be omitted, the packaging process can be simplified, and the manufacturing cost can be reduced, and as a result, the vacuum powder heat insulator can be reduced in cost.

Moreover, since the deaeration of the filler powder is performed before the bag is filled, the powder can be favorably deaerated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an apparatus suitable for carrying out the present invention, FIG. 2 is a side sectional view of a vacuum powder heat insulator manufactured by the apparatus of FIG. 1, and FIG. 3 is a conventional vacuum heat insulating material. 4 is a schematic perspective view showing a conventional vacuum heat insulating material manufacturing process in the order of steps, and FIG. 8 is a side cross sectional view showing a conventional vacuum heat insulating material manufacturing apparatus. 15 …… Vacuum cyclone 17,19 …… Vacuum hopper 23 …… Vacuum chamber 34 …… Vacuum powder insulation 35 …… Bag 36 …… Filler powder

Claims (1)

[Claims] 1. A part or all of the filler powder is supplied into a vacuum cyclone for deaeration, then sequentially transferred to a plurality of vacuum hoppers for deaeration at least once, and then this depressurization is performed. Vacuum powder insulation characterized in that the powder kept in a state is supplied into a vacuum chamber under vacuum conditions, and within this champer, the powder is filled and sealed in a package made of a gas impermeable material. Body manufacturing method.