JPH0615946B2 - Insulation box manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a heat insulating box body in which a transparent window is provided in the upper front part of a storage room surrounded by a heat insulating material, and more specifically to a transparent box. The present invention relates to a manufacturing method when a multilayer transparent plate is used as a window.

2. Description of the Related Art Japanese Unexamined Patent Publication No. 60-165487 discloses a method for manufacturing a heat insulating box for a low temperature showcase having an opening and a protruding wall formed on one surface. In this example, the transparent window is fixed after the foamed heat insulating material is filled in the box formed by the inner and outer boxes and the breaker. According to this method, the pressure generated by the foaming and solidification of the undiluted solution of the foam insulation material may cause the groove for arranging the see-through window of the breaker to be deformed from its original shape, resulting in a narrow inlet side. there were. In this case, since it is impossible to fix the see-through window to the groove portion as it is, it is necessary to correct the groove portion before fixing, which is very troublesome.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the manufacturing method disclosed in the above publication, the work of correcting the groove portion must be performed after the completion of foaming and before disposing the multilayer transparent plate as the transparent window. There was a problem that it was very troublesome and time-consuming.

On the other hand, it is a method to fill the foam insulation into the box with the multilayer transparent plate fixed, but the conventional method that is not this method is to put the box in the heating furnace before filling with the foam insulation and reserve it. Heating is generally carried out, and if it is applied to this method, it is easily expected that the multilayer transparent plate will be cracked at this preheating stage, and therefore it is not generally adopted. This is for the following reason. In order to ensure heat insulation of the multi-layer transparent plate, the interval between the transparent plates is set to about 1 mm to 10 mm so that air existing in the interval does not convection (see Japanese Patent Publication No. 61-3201). This multi-layer transparent plate does not crack due to thermal deformation of each transparent plate due to preheating, but the expansion pressure due to the temperature rise of the internal air is , And the vertical aspect ratio causes cracking when the transparent plate exceeds the allowable stress. It should be noted that the foaming undiluted solution to be filled has the property that the higher the heating temperature due to the preheating, the better and quicker the surrounding condition becomes, and the time required to complete the foaming is shortened. there were. Therefore, the heating temperature should be set as high as possible.

When the foaming work was performed with the temperature set to about 80 ° C, it was found that the thickness of the transparent plate was 3 mm and the air layer thickness was 6 mm, and the transparent plate had a vertical aspect ratio of more than 6 and less than 5. However, if the length of the short side is about 17 cm or more, cracking occurred. Since the foaming phenomenon involves a large movement such as reversing of the box, the handling thereof may be troublesome, so that the foaming in the glass-filled state has not been performed.

Therefore, in the present invention, when a box body in which a see-through window made of a multi-layer transparent plate is fixed is filled with a foamed heat insulating material, a heat-insulating box body in which cracks do not occur in the multi-layer transparent plate is produced. The task is to provide a method.

[Structure of Invention]

Means for Solving the Problems The method for manufacturing a heat insulating box according to the present invention is such that cracks occur in a multilayer transparent plate in a state where a multilayer transparent plate is arranged on one side wall of a box formed by connecting both inner and outer boxes. After heating to a predetermined temperature below the temperature (that is, the temperature at which cracks will occur), the box body is fixed with a jig and a foam insulation material is injected and filled between the inner and outer boxes to form a heat-insulating box body. is there.

The box body is heated at a temperature lower than the cracking temperature of the double-layered transparent plate placed on one side wall of the work box body, so it regulates the expansion of the air in the adiabatic space and occurs with the expansion of the air. Since the amount of deflection of the transparent plate itself will be regulated, the box body can be filled with foam insulation without cracks in the transparent plate and the box body after foaming can be attached to the multi-layer transparent plate. The correction work of is unnecessary.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. 1 to 10.

(1) is a heat insulation box typified by a low temperature showcase used for displaying and selling ice cream, sorbet, etc., and a heater (2
Two transparent doors (3) (3) on the left and right sides that open and close the opening in the front half of the transparent window (2) with B)
The main body of the heat-insulating box is provided with a door storage part (4) for storing the doors (3) and (3) when the transparent doors (3) and (3) are opened in the latter half of the upper surface.
(5) and a machine room (6) in which indispensable mechanical parts for cooling are arranged below the heat insulating box body (5). The heat insulating box body (5) is an inner box (11) made of metal, for example, a hot-dip galvanized steel plate having an upper surface opened to define a storage chamber, and an inner box with an appropriate space between the inner box (11). The outer box (12) made of metal, such as a hot-dip galvanized steel plate, which houses
Box body (1A) composed of a resin frame body (13) that covers the upper opening of the space surrounded by the two boxes and is arranged over the upper end of 2)
The space is formed by foaming and filling a foam insulation material (14) such as hard polyurethane. Then, the opening (15) for taking in and out the product and this opening (15) on one wall surface (the upper surface in this example)
And a projecting wall (16) extending in the direction. In addition, transparent window
(2) is formed of a multi-layer transparent plate having a heat insulating effect. In this example, two transparent glasses (2A) are held by a spacer at an appropriate interval to improve the adhesion between the two glasses and the spacer. Both are fixed by a sealing material having adhesiveness such as thiocol, and a dew condensation preventing heater (2B) is arranged on the outer periphery of the sealing material.

The inner box (11) has front, back, left and right bottom walls (1A) to (11D).
Consisting of a meandering low-temperature refrigerant pipe provided on the outer peripheral surface of the pipe-on-sheet type main cooler (17) and arranged in the latter half of the upper surface. -The inside (19) of the refrigerator is cooled by the plate-shaped auxiliary cooler (18) provided with rising pieces on the left and right edges. Also, the outer box (1
2) is a front wall (12) where heat exchange air (20) as a heating element consisting of a meandering refrigerant tube through which a high-temperature gas-liquid mixed refrigerant or liquid refrigerant flows in the refrigeration cycle is attached to the inner surface with an aluminum tape (12).
A), a back wall (12B) having a bent side and a forward groove defined by the bent side at the upper end extending above the front wall (12A), and both left and right walls (12C). ), And a bottom wall (12D) that gently inclines backward and has a foam insulation material (14) injection hole at the rear edge and an appropriate number of exhaust holes at the front edge, and the front, back, left, and right edges. Of the heat exchanger (2E).
At 0), the front wall (12A) is prevented from dew condensation. Even if an electric heater is arranged as the heating element instead of the heat exchanger (20), the same dew condensation preventing effect can be obtained.

The machine room (6) consists of the lower part of the front wall (12A) of the outer box (12) and the left and right walls (1
2C), the bottom wall (12D), the first exhaust passage (21) that opens vertically at the upper edge, and the second exhaust that is located below the first exhaust passage (21) and opens in the front-rear direction. A removable cover (23) that forms a passage (22) and covers the opening for removing mechanical parts provided on the back side of the heat-insulating box body (5) and the outer box (1
2) A refrigerant compression that is defined by the base (25) that forms the intake passage (24) between the lower end of the front wall (12A) and the main / auxiliary coolers (17) and (18). Machine (26) based (2
5) Connect the wire fin tube type condenser (27) to the intake passage.
It is fixed to a pair of support tools provided on both front and rear edges of (24).

Further, a night cover support tool (34) is attached to the back of the outer box (12) so as to project more than the cover (23), and the night cover (35) can be inserted and removed by this support tool (34). The warm air coming out of the first exhaust passage (21) and rising is directed by the support tool (34) and the night cover (35) and is formed on the lower surface of the rear portion of the door storage section (4). It leads to the ventilation port (39) so that the door storage (4) can be ventilated. The night cover support (34) is formed between the fixing piece (36) for fixing to the back of the outer box, the receiving groove (37) for receiving the lower end of the night cover, and the fixing piece and the receiving groove. And a ventilation part (38) for receiving the side edges of one side of the night cover (35). However, this support may be attached after the completion of foaming.

Further, the door storage section (4) includes a resin shade plate (30) located on the front surface, a metal top wall (31) located on the upper surface, and an upper wall of the outer box (12) located on the lower surface. A lighting device (32), such as a straight tube fluorescent lamp, for illuminating the inside and outside of the refrigerator, which is defined by (12E), is housed when the transparent doors (3) and (3) are opened.

In the frame body (13) arranged over the upper ends of both the inner and outer boxes,
The transparent window (2) is held and fixed in the recesses (8) formed on the front walls of both the inner and outer boxes, but in order to make the left and right parts of the rectangular transparent window look like an arc, this example Then, the first frame body configured to divide the frame body into three sections and to combine them into each other.
(13A) and the second frame (13B) arranged at the front end of the projecting wall (16). Furthermore, the first frame body (13A) has a left frame portion (40) and a right frame portion (not shown) that correspond to the left and right walls of the box body, and a front frame portion (41) that corresponds to the front wall of the box body. The left frame part (40) and the front frame part (41) will be briefly described because they are divided and are symmetrically configured with the left and right frame parts facing each other. The recess (8) is formed by surrounding the end portion by the front frame portion (41) and the connecting portion (47), and the front frame portion (41)
As shown in FIG. 7, a cross section of the insert piece is formed with a groove (42) as a groove for inserting and holding the lower end of the transparent window and extends downward and inserts an upper end of the front wall of the inner box (43). , And a fixed piece (44) which is connected and connected to the left and right frame portions and which has the function of serving as the core frame of the transparent window (2) by inserting the upper end of the front box of the outer box. The left frame part (40) is formed on the lower part of the inclined part (45) that is formed with an upward slope toward the rear and the dew that is formed on the front part of this inclined part (45) and that has propagated through the inclined part. The dew receiving portion (46) having an opening and the dew receiving portion (46) are separated from each other, and the connecting portion (47) is formed so as to project from the inclined portion so as to connect with the front frame portion (41). It has and.
This connecting part communicates with the concave groove (42) and also has a transparent window.
A fixing groove (48) for inserting and holding the left end of (2), and a connecting piece (49) that digs under the fixing piece (44) of the front frame part (41) at its tip have a surface with the fixing piece (44). Decorative pieces that act together as a window frame
(50) and are provided. A plurality of ribs (51) for preventing rattling before and after the transparent window are formed on the front surface of the back wall of the fixing groove (48). Further, the inclined portion (45) has a rail receiver (52) for holding the left rail (60) formed on the inner side of the upper surface, and for energizing electric parts such as a heater for a transparent window and a fluorescent lamp on the outer side of the upper surface. The wiring part (53) for processing the wiring is formed, and the insertion piece (54) for inserting the upper end of the inner box is formed inside the lower surface. The rail receiver (52) is a retaining piece (55) for retaining the stop piece (61) formed on one end side of the left rail (60) and a receiving piece for receiving the lower surface of the left rail.
(56) and a standing piece (57) for suspending a hooking piece (62) formed on the other end side of the rail (60) are provided. Further, the left rail (60) is provided with a mounting portion (63) on which the transparent door (3) is slidably mounted and a restriction portion (64) for restricting lateral displacement of the door.

(70) is a window fixing frame made of resin which is inserted and held at the upper end of the transparent window (2) to fix the transparent window (2) and which is covered with a handrail (80) which will be described later. It is arranged corresponding to the wall. This window fixing frame (70) is a part (8) of the handrail (80).
3) a receiving portion (71) that receives the lower surface, a locking groove (72) that is formed at one end of the receiving portion (71) and that fits the locking claw (86) of the handrail,
A flexible hanging piece (73) provided upright on the lower surface of the receiving portion (71)
And a window fixing groove as a fixing portion, which is provided at the tip of the hanging piece (73) and has an opening narrower than the inside so that the upper end of the transparent window (2) can be firmly fitted and has a restoring property. (74)
And a support piece that supports the lower surface of the dew receiver (85) of the handrail (80).
(75) and.

(80) is a front decorative frame (81) that covers the window fixing frame (70), and left and right decorative frames (82) (82) that cover both left and right frame parts (40) and press and fix the left and right rails (60). It is a metal handrail with excellent corrosion resistance, such as stainless steel, consisting of a front decorative frame (81)
Is an R portion (83) having a downward slope, a door contact (84) hanging from the rear end of the R portion, an exposure receiver (85), and a locking claw (86) formed at the front end of the R portion. The left and right decorative frames (82), (82) are composed of a pressing piece (87) for pressing the left and right rails (60) at the inner ends, and a covering portion (88) for covering the wiring portions of the left and right frame portions.

Next, when fixing the transparent window (multi-layer transparent plate),
For both inner and outer boxes (12) (12) arranged with appropriate intervals,
The frame body is arranged and fixed to the upper ends of both the inner and outer boxes such that the frame body (13) formed by the connection and connection is held across the inner and outer boxes.
Then, the lower end of the transparent window (2) is in the concave groove (42) of the front frame part (41) of the frame body, and the left and right ends of the transparent window (2) are in the fixing grooves (48) of the left and right frame parts (40). Insert the transparent window from above so that it is retained. After this, the window fixing groove (7) of the window fixing frame (70) is resisted against the restoring force.
Widen the lower end opening of 4) and fit and hold the upper end of the transparent window (2). Then, the standing pieces (5) of the rail receivers (52) of the left and right frame parts (40) are
Suspend the left and right rails (60) of 7), and use the pressing pieces (87) of the left and right decorative frames (82) and (82) of the handrail (80) to respectively
While fixing (60) by pressing, locking claws (86) of the front decorative frame (81)
To the locking groove (72) of the window fixing frame (70),
0) and the left and right frame parts (60) to cover the handrail (80)
To fix. For both the inner and outer boxes assembled in this state,
The space formed by both boxes is filled with foamed heat insulating material to form a heat insulating box (1).

Here, the manufacture of the heat insulating box will be described with reference to FIGS.

First, the inner box (11) in which the heat insulating block (90) is adhered to the outer surface of the bottom wall (11D) with an adhesive is connected to the outer box (12) by the frame body (13), and the heat insulating block is provided in the space. (90) and the partition material (91) are interposed, a gap is formed between the heat insulating block and the bottom wall (12D) of the outer box, and an opening (15) and a projecting wall (16) are formed on one side surface. Assemble the formed box (1B).

Then, the frame body (front frame portion) (41) having the concave groove (42) corresponding to the recess formed in the upper part of the front wall of the box body (1B) is attached to both the inner and outer boxes (1
1) After arranging so as to straddle (12), the groove of this front frame (41)
The transparent plate (2) is fitted into (42) and the transparent plate is placed in the recess. Then, the box body (1B) is transferred to the heating furnace (92) and preheated to a predetermined temperature. Next, after the box body (1B) is installed with the opening (15) and the projecting wall (16) as the upper surface, the nest (93) preheated to the above-mentioned predetermined temperature from the opening (15) into the inner box (11). ) Is inserted and placed on the front half of the bottom wall (11D), this nest is slid rearward and placed immediately below the projecting wall (16) as shown in FIG. Due to the placement of this nest, the bottom wall (11D) of the inner box is nested (93).
While it inflates and flexes toward the space (P) side under the weight of, the heat insulation block (90) hits the bottom wall (12D) of the outer box due to this flexure,
The gap is eliminated.

After placing the nest, the nest was placed in the inner box (11) and the box body (1B) was turned upside down and preheated to a predetermined temperature so that the opening (15) and the projecting wall (16) were on the lower surface. The inner and outer jigs (95) (96) press the box body (1B) as shown in FIG. With the inversion, the weight of the nest (93) is the inner wall of the projecting wall (16) and the auxiliary cooler (18).
As a result, the bending of the bottom wall (11D) of the inner box is eliminated, and the heat insulating block (90) is separated from the outer wall (12D) of the outer box and the gap (94) is formed again. . In such a state, by injecting into the space (P) of the foaming undiluted solution (Q) through the injection hole (97), the undiluted solution (Q) foams and grows as shown by the arrow in FIG. Air is pushed out of the exhaust hole (98) to form the foam insulation (14),
(1) is obtained.

Next, the predetermined heating temperature at the time of preheating will be briefly described. This predetermined temperature (hereinafter referred to as the allowable heating temperature)
Is set below the crack generation temperature at which cracks occur in the multi-layer transparent plate (2), and when the multi-layer transparent plate is heated, the crack generation temperature expands with that heating. It is the temperature at which the transparent plate breaks due to the expansion pressure of the internal air. The allowable heating temperature is the short side length a, the long side length b, the glass plate thickness t, and the glass interval x of the multilayer transparent plate.
(The unit is [cm] in all cases). In this example, the pressure P that acts during heating [P = {t ² × (allowable stress of glass)} / {(first coefficient by b / a) × a ² } ...] Deflection amount δ [δ = {(Second coefficient by b / a) × P × a ⁴ } / {(Young's modulus of glass) × t ³ } ...] Radius r when bent [r = {δ ² + (a / 2) ² } /(2.8) ...] Expanded volume V of air (for double-sided expansion) The temperature T when the multi-layered transparent plate breaks from the four
₂ Find [T ₂ = P ₂ V ₂ T ₁ / P ₁ V ₁ = (P + P ₁ ) (V + V ₁ ) T ₁ / P ₁ V ₁ …]. In addition, θ is the central angle in the short side direction when the multilayer plate is bent, and T ₁ , P ₁ , and V ₁ are the temperature, air layer pressure, and air layer volume at the time of manufacturing the multilayer transparent plate, respectively.

Further, as an example of the case where the lateral ratio exceeds 5, the allowable stress of glass = 250 [kg / cm ² ], the first coefficient by b / a =
0.75, second coefficient by b / a = 0.147, Young's modulus of glass = 7.5 × 10 ⁵ [kg / cm ² ], b = 12
5, t = 0.28, x = 0.61, P ₁ = 1.03 [kg
/ Cm ² , T ₁ = 300 ° K, a = 11,15,25
Similarly, the first coefficient = 0.74, the second coefficient = 0.144, and b = 65 as an example in which the vertical ratio is less than 5.
Assuming that, a total of 6 cases of a = 11, 15, 25 were observed statically.

(i) When b = 125 and a = 11 T ₂ = Z = 374.1 [° K] = 101.1 [° C.] (ii) When b = 125 and a = 15 T ₂ = Z = 352. 98 [° K] = 79.98 [° C] (iii) When b = 125 and a = 25 T ₂ = Z = 361.9 [° K] = 88.9 [° C] (iv) b = 65, a = 11 when T ₂ = 374.9 [° K] = 101.9 [℃] (v) b = 65, T 2 = 353.3 [° K] when a = 15 = 80.3 [℃ ] (Vi) When b = 65 and a = 25 T ₂ = 361.8 [° K] = 88.8 [° C] From these results, it can be expected that T ₂ has the lowest point, so the numerical substitution method is used. When the lowest point of T ₂ was determined at, the short side length was about 17.8 cm and was about 77 ° C.

As the crack generation temperature of the multilayer transparent plate at x = 0.61 [cm], a temperature about 10 ° C. lower than the calculated value is selected in consideration of the safety factor.

On the other hand, the crack initiation temperature decreases as the air layer thickness of the multilayer transparent plate increases, and this relationship is shown in FIG. However, as the value of a, the length at which the calculated crack initiation temperature is minimized is quoted. Then, the actual crack initiation temperature is selected to be about 10 ° C lower than the crack initiation temperature calculated by calculation (about 67 ° C in this example), and the actual crack initiation temperature is set in the furnace. The heating temperature for heating is set to a lower temperature of 60 ° C.
When heating was performed at 60 ° C. and the foaming stock solution was filled, no cracks occurred in the multilayer transparent plate.

As described above, prior to the foaming work of the box body (1B), the multilayer transparent plate
After fixing (2) to the groove (42) of the frame (13A), this box (1B)
Since it is preheated in the heating furnace (92) and then filled with the undiluted solution (Q) of the foam insulation material, the frame body (13) is generated by the foaming pressure generated by the foaming and solidification of the undiluted solution (Q). Even if is pressed, the deformation of the multilayer transparent plate (2) is suppressed, and the multilayer transparent plate (2) can be firmly fixed. Also,
Since the predetermined temperature for preheating is set below the crack generation temperature of the double-layer transparent plate (2) (crack generation avoidance temperature), the air in the adiabatic space of the double-layer transparent plate (2) expands during this preheating. In addition to the upper limit being set, the deflection of the transparent plate due to this air expansion toward the outside can be suppressed within a range that does not cause the transparent plate to crack, and heating of the multilayer transparent plate The generation of cracks due to (1) will not occur, and the manufacturing efficiency of the heat insulating box can be improved.

〔The invention's effect〕

As described in detail above, according to the present invention, since the foaming work is performed in the state where the multilayer transparent plate is arranged, it is possible to manufacture the heat insulating box body with the transparent plate after the foaming is completed, Due to the presence of the transparent plate, the expansion of the box body itself due to the foaming and solidification can be suppressed at least at the transparent plate disposition site. Further, it has been a matter of concern from the past to perform foaming in a state in which the multi-layer transparent plate is arranged, but as the predetermined temperature in the preheating, the size and the thickness of the multi-layer transparent plate to be arranged are determined. By setting the temperature below the crack initiation temperature, that is, the crack initiation avoidance temperature, the expansion of the air in the adiabatic space and the amount of deflection of the transparent plate due to heating are suppressed, so that the transparent plate is prevented from cracking. it can.

[Brief description of drawings]

Each drawing shows one embodiment of the present invention, FIG. 1 is a cross-sectional view of a state where the box is transferred to a heating furnace, FIG. 2 is an external perspective view of the heat insulating box, and FIG. 3 is A of FIG. -A sectional view, FIG. 4 is an enlarged sectional view of part B of FIG. 3, FIG. 5 is an exploded perspective view illustrating fixing of a transparent window, and FIG. 6 is a schematic perspective view showing a corner portion of a box, 7 is a sectional view taken along the line CC of FIG. 2 with the door removed, FIG. 8 is a sectional view of the box body fixed to a jig, and FIG. 9 is a frame body with a transparent plate fixed to the frame body. FIG. 10 is a schematic perspective view showing the relationship between the thickness of the air layer of the multi-layer transparent plate and the crack generation temperature (calculated value). (1) …… Insulation box, (1B) …… Box, (2) …… Multilayer transparent plate,
(11) …… Inner box, (12) …… Outer box, (Q) …… Foam insulation, (9
2) …… heating furnace, (95) (96) …… foaming jig.

Claims (1)

[Claims] 1. A box after heating to a predetermined temperature lower than a crack generation temperature of the transparent plate in a state where a multi-layered transparent plate is arranged on one side wall of a box body formed by connecting both inner and outer boxes. A method for manufacturing a heat-insulating box body in which a body is fixed by a jig heated to the predetermined temperature and a foam heat insulating material is injected and filled between the both boxes to form a heat-insulating box body.