JP5640501B2 - Showcase door - Google Patents

Description

  The present invention relates to a door for a showcase that closes a front opening of a refrigerated showcase.

  The door for the showcase that closes the front opening of the refrigerated showcase is arranged along the transparent glass plate with a transparent conductive film that covers the entire surface, which functions as a dew-proof heater, and on both sides of the transparent glass plate. And a pair of external connection electrodes that are electrically connected to the transparent conductive film (see, for example, Patent Document 1).

JP-A-6-294573

  However, in the door for a showcase described above, the external connection electrode is exposed on the surface of the transparent glass plate, and therefore, condensation occurs on the surface of the transparent glass plate in a region surrounded by the external connection electrode and the frame.

  This invention is made | formed in view of the above, Comprising: It aims at providing the door body for showcases which can prevent the dew condensation on the surface of a transparent glass plate.

In order to solve the above-described problems and achieve the object, the present invention provides a transparent glass plate with a transparent conductive film functioning as a dew-proof heater, and an upper edge and a lower edge of the transparent glass plate. A pair of external connection electrodes disposed along the power supply and energizing the transparent conductive film, and a pair of upper and lower horizontal frames that hold the transparent glass plate in a mode of covering the external connection electrodes, and the horizontal frame And a frame composed of a pair of left and right vertical frames that hold the transparent glass plate and are narrower than the width .

  Further, the present invention is characterized in that, in the above-described showcase door body, the conductive film glass heater constituted by the transparent conductive film and the glass frame dew-proof heater provided in the frame are connected in series. .

  Since the door for a showcase according to the present invention includes a pair of upper and lower frames that hold the transparent glass plate so as to cover the external connection electrode, the region surrounded by the external connection electrode and the frame is not exposed. It is possible to prevent condensation on the surface of the transparent glass plate.

  In addition, since the conductive glass heater formed of the transparent conductive film and the glass frame dew-proof heater provided on the frame are connected in series, the fluctuation of the power consumption due to the fluctuation of the resistance value of the transparent conductive film is reduced with the conductive glass heater. This can be made smaller than when the glass frame dew-proof heater is connected in parallel.

FIG. 1 is a front view of a showcase in which a front opening is closed with a showcase door body according to an embodiment of the present invention. FIG. 2 is a perspective view showing a door for a showcase that is an embodiment of the present invention. FIG. 3A is a front view showing the door for the showcase shown in FIG. 3-2 is an enlarged view showing a main part of the door for a showcase shown in FIG. 3-1. FIG. 4 is a circuit diagram showing the connection between the conductive glass heater and the glass frame dew-proof heater.

  Hereinafter, embodiments of a door for a showcase according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a front view of a showcase in which a front opening is closed by a showcase door body according to an embodiment of the present invention, and FIG. 2 shows the showcase door body according to an embodiment of the present invention. It is a perspective view. FIG. 3A is a front view showing the door for the showcase shown in FIG. 2, and FIG. 3-2 is an enlarged view showing the main part of the door for the showcase shown in FIG. It is.

  The showcase illustrated here is installed in a store such as a convenience store or a supermarket, and holds products such as refrigerated products and frozen products in a refrigerated state or a frozen state, and the front opening is an embodiment of the present invention. When the product is taken out from the showcase by being closed by the showcase door 1 (hereinafter referred to as a door), the door 1 is opened and closed when the product is replenished to the showcase.

  As shown in FIG. 1, a door body 1 according to an embodiment of the present invention enables a product housed in a showcase to be visually recognized from the outside while the front opening of the showcase is closed. 11 is provided.

  As shown in FIG. 2, the transparent glass plate 11 is a rectangular glass plate, and a transparent conductive film 12 that functions as a dew-proof heater is attached to one surface serving as a front surface. The transparent conductive film 12 is manufactured and managed in consideration of the yield, and the resistance value of the transparent conductive film 12 is allowed to vary ± 20%. Therefore, for example, when the conductive film glass heater 2 formed by the transparent conductive film 12 requires a capacity of 125 W, the transparent conductive film 12 having a resistance value in the range of 48Ω to 80Ω is employed. .

  As shown in FIG. 3, a pair of external connection electrodes 13 that are connected to a power source (not shown) and energize the transparent conductive film 12 are connected to the front upper edge and the front lower edge of the transparent glass plate 11. It is arranged.

  Further, the door body 1 includes an upper frame 31 that holds the upper edge of the transparent glass plate 11 in a mode of covering the external connection electrode 13 disposed on the upper edge of the front surface of the transparent glass plate 11, and the front surface of the transparent glass plate 11. A lower frame 32 that holds the lower edge of the transparent glass plate 11 so as to cover the external connection electrode 13 disposed on the lower edge portion. The upper frame 31 and the lower frame 32 are a pair of upper and lower sides. A horizontal frame (frame 30) is formed.

  The door 1 includes a left frame 33 that holds the left edge of the transparent glass plate 11 and a right frame 34 that holds the right edge of the transparent glass plate 11. Constitutes a pair of left and right vertical frames (frame 30). Note that the vertical frame (left frame 33, right frame 34) does not need to cover the external connection electrodes, so the width and the thickness of the vertical frame (the upper frame 31, the lower frame 32) are reduced compared to the horizontal frame (upper frame 31, lower frame 32). This increases the see-through area of the door 1 and improves the visibility.

  The horizontal frame (upper frame 31, lower frame 32) and vertical frame (left frame 33, right frame 34) described above are made of metal, resin, or a composite of metal and resin, as shown in FIG. Thus, the glass frame dew-proof heater 4 is provided inside. The glass frame dew-proof heater 4 is for preventing condensation on the outer surface of the horizontal frame (upper frame 31, lower frame 32) and vertical frame (left frame 33, right frame 34), and is connected to a power source. When the glass frame dew-proof heater 4 is energized, the horizontal frame (upper frame 31, lower frame 32) and vertical frame (33, 34) are heated.

  FIG. 4 is a circuit diagram showing the connection between the conductive glass heater and the glass frame dew-proof heater. As shown in FIG. 4, the conductive film glass heater 2 formed by the transparent conductive film 12 and the glass frame dew-proof heater 4 are connected in series.

  As described above, the showcase door body 1 according to the embodiment of the present invention includes the upper frame 31 and the lower frame 32 (a pair of upper and lower sides that hold the transparent glass plate 11 in a mode of covering the external connection electrode 13 ( A horizontal frame), the region surrounded by the external connection electrode 13 and the frame 30 is not exposed, and condensation on the surface of the transparent glass plate 11 can be prevented.

  In addition, since it is not necessary for the vertical frame (left frame 33, right frame 34) to cover the external connection electrode 13, the width of the vertical frame (left frame 33, right frame 34) can be reduced and the thickness can be reduced. The see-through area of the door body 1 is enlarged and the visibility is improved. Furthermore, since the external connection electrode 13 is not exposed, the appearance of the door body 1 is improved.

  Next, it is verified which is more advantageous to connect the conductive film glass heater 2 and the glass frame dew-proof heater 4 in parallel or in series. Here, the required capacity of the conductive film glass heater 2 according to the embodiment of the present invention is 125 W, the required capacity of the glass frame dew-proof heater 4 is 60 W, and the resistance value of the conductive film glass heater 2 is the film of the transparent conductive film. It shall vary ± 20% depending on the thickness.

First, it verifies about the case where the electrically conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in parallel.
(1) The resistance of the conductive glass heater 2 is 80Ω.
^{R = E 2 / P (R} : resistance, E: Voltage, P: power) than ^{R = 100 2/125 = 80} (Ω)
(2) The power consumption of the conductive glass heater 2 varies between 125W and 208W.
P ^{= E} 2 / R than ^{Pmin = 100 2/80 = 125} (W)
Pmax = 100 ² /(80×0.6)=208 (W)
(3) The current flowing through the conductive glass heater 2 varies between 1.25A and 2.08A.
From I = E / R Imin = 100/80 = 1.25 (A)
Imax = 100 / (80 × 0.6) = 2.08 (A)
(4) The resistance of the glass frame dew-proof heater 4 is 166Ω.
R ^{= E} 2 / P from ^{R = 100 2/60 = 166} (Ω)
The capacity of the glass frame dew-proof heater 4 does not vary unlike the conductive film glass heater 2.
(5) The current flowing through the glass frame dew-proof heater 4 is 0.6A.
From I = E / R I = 100/166 = 0.6 (A)
(6) The maximum current that flows when the conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in parallel is 2.68 A.
Imax = 2.08 + 0.6 = 2.68 (A)

Next, it verifies about the case where the electrically conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in series.
(1) The power consumption of the conductive film glass heater 2 and the glass frame dew-proof heater 4 is 185 W.
P = P ₁ + P ₂
(P ₁ : heater capacity of conductive film glass heater, P ₂ : heater capacity of glass frame dew-proof heater)
P = 125 + 60 = 185 (W)
(2) The electric current which flows into the electrically conductive film glass heater 2 and the glass frame dew-proof heater 4 is 1.85A.
From I = P / E I = 185/100 = 1.85 (A)
(3) The resistance of the conductive film glass heater 2 varies between 36.52 and 21.91Ω.
From R = P / I ² R ₁ max = 125 / 1.85 ² = 36.52 (Ω)
R ₁ min = 36.52 × 0.6 = 21.91 (Ω)
(4) The resistance of the glass frame dew-proof heater 4 is 17.53.
From R = P / I ² R ₂ = 60 / 1.85 ² = 17.53 (Ω)
The resistance of the glass frame dew-proof heater 4 does not vary unlike the conductive film glass heater 2.
(5) The resistance when the conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in series is 39.44Ω.
From R = R ₁ + R ₂ R = 21.91 + 17.53 = 39.44 (Ω)
(6) The current that flows when the conductive glass heater 2 and the glass frame dew-proof heater 4 are connected in series is 2.53 A at maximum.
From I = E / R Imax = 100 / 39.44 = 2.53 (A)

Therefore, there is a difference of 0.15 A between the current flowing when the conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in parallel and the current flowing when connected in series.
I = 2.68−2.53 = 0.15 (A)

  When the conductive film glass heater 2 and the glass frame dew-proof heater 4 are connected in series, it means that 6% power consumption can be suppressed. Moreover, since it also means that the heater capacity can be suppressed by 6%, it is possible to prevent the heater from overheating.

  As described above, the showcase door 1 according to the embodiment of the present invention has the conductive film glass heater 2 and the glass frame dew-proof heater 4 connected in series, so that it consumes more power than when connected in parallel. It is possible to prevent the conductive film glass heater 2 and the glass frame dew-proof heater 4 from overheating.

1 Door (Showcase door)
11 transparent glass plate 12 transparent conductive film 13 external connection electrode 2 conductive film glass heater 30 frame 31 upper frame (horizontal frame)
32 Bottom frame (horizontal frame)
33 Left frame (vertical frame)
34 Right frame (vertical frame)
4 Glass frame dew-proof heater

Claims (2)

A transparent glass plate with a transparent conductive film functioning as a dew-proof heater applied to the entire surface;
A pair of external connection electrodes disposed along the upper and lower edges of the transparent glass plate, connected to a power source and energized to the transparent conductive film,
A pair of upper and lower horizontal frames that hold the transparent glass plate in a manner covering the external connection electrodes, and a pair of left and right vertical frames that are formed with a narrower width than the width of the horizontal frame and hold the transparent glass plate A door for a showcase, characterized by comprising:   2. The door for a showcase according to claim 1, wherein a conductive film glass heater constituted by the transparent conductive film and a glass frame dew-proof heater provided on the frame are connected in series.

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