FR2534007A1 - GLASS DOOR FOR FREEZERS AND COLD ROOMS - Google Patents

Abstract

GLASS DOOR FOR FREEZERS AND COLD ROOMS, IN WHICH THE FRONT PANEL 2 OPPOSES THE FREEZER AND THE COLD CHAMBER IS HEATED BY AN ELECTRICALLY CONDUCTIVE LAYER FIXED TO THE INSIDE SURFACE OF THE PANEL. GLASS DOOR 1 CHARACTERIZED IN THAT IT CONTAINS FOUR PANELS 2, 3, 4, 5 PARALLEL TO ONE TO THE OTHERS AND SEALED AGAINST OTHERS, IN A MANNER KNOWN IN ITSELF BY SEALS 8, 9, 10 PLACES ALONG THE EDGES OF THE PANELS. THE INVENTION APPLIES TO FREEZERS AND COLD ROOMS OF STORES.

Description

2534007.

  "Glass door for freezers and cold rooms".

  The invention relates to a glass door for

  freezers and cold rooms for use in

  This door is mainly used to display frozen products in food stores. These doors are increasingly used to isolate freezers and cold rooms from the rest of

  the piece in the food stores The merchandise

  frozen foods are exposed through the glass door and when a consumer wants to choose a product, that customer opens the door, takes the product,

then close the door.

  As the doors are frequently open, these

  doors are alternatively exposed to the atmosphere of

  sin and the atmosphere of the freezer.

  The doors normally comprise two or three glass panels, and most often three glass panels In this case, the panel facing the store and the panel facing the freezer are made of tempered glass, so as to be able to withstand normally the stresses without risking to burst The middle panel is the

  more often constituted by a window glass.

  As the doors are alternately exposed to different atmospheres of relative humidity and temperature, the glass panel facing the store is normally heated to prevent fogging, so that one can always see

  clearly the goods on display.

  The front panel, facing the store, is normally heated with a heat input of approximately 120 watts per m 2.

  watts to heat the door frame These precau-

  tions keep the door transparent and without fogging when the temperature of the store is for example + 250 C, the temperature of the freezer being for example of

-300 C.

  Under these conditions, about 60% of the heat

  brought into the freezer and 40% of this

  in the store It follows that we do not

  about 72 to 96 watts / m 2 in this freezer

  energy intake costs a significant amount per year when

  that a number of doors, and for example five doors of 1 m 2 each are used A permanent energy input of 600 to 800 watts is then necessary which, for an energy price of 0.4 franc per K Wh, leads to an expense

from 600 to 800 francs a year.

  In addition, it is necessary to add to this expenditure the cost of the additional energy expended by the refrigeration machine of the freezer to absorb the heat brought to it. The cost of this energy is very high, because the refrigeration machine is far away.

to have a return of 100%.

  The invention aims to overcome these drawbacks.

  of the prior art and concerns for this purpose a glass door for freezers and cold rooms, in which the front panel opposite the freezer and

  to the cold room is heated by an electric layer-

  conductive element attached to the inner surface of the panel, glass door characterized in that it comprises four -3 panels parallel to each other and sealed the

  against each other, in a manner known per se

  seals placed along the edges of the panels.

  The invention will be described in detail with reference to

  in the attached single figure representing schemati-

  only a sectional view of a door according to the invention.

  The single figure schematically shows a glass door according to the invention comprising a front panel 2 tempered glass located on the opposite side to the cold room, and a rear panel 3 also made of tempered glass

  located on the side of the cold room.

  The front panel is designed to be heated, heating being achieved by covering this panel with a

  extremely thin layer of electrically conductive material

  such as, for example, stannic oxide at the ends of the upper and lower

  panel, the conductive layer is connected to

  connec- tors 6, 7 themselves connected to a source

regulated voltage.

  Between these panels 2, 3 lie, according to the

  vention, two intermediate panels 4, 5 made of

preferably glass pane.

  The invention thus uses four panels 2, 3,

  4, 5 arranged parallel to each other.

  are sealed on their edges, one against the other

  other, by seals 8, 9, 10.

  The use of four panels, including

  2 is heated, based on the observation that the heating consumption can be reduced considerably in this way, and that at the same time it can reverse the main direction of heat loss.

  compared to a conventional glass door with three panes

glasses of glass.

  The use of more panels

  of glass improves the technical results in a

  significant. Under the same reference conditions as those indicated in the introduction above, ie for a store temperature of + 251 C and a temperature of the freezer chamber of 301 C, it is sufficient, with the door according to the invention, to heat the front panel 2

  with a power of less than 50 watts / m 2, and preferably

  40 watts / m 2, that is to say with a power half of the previous power In addition, the main direction of heat loss is reversed In a conventional glass door, about 60% of the heat supplied passes into the cold room while about

  % of this heat goes into the store.

  In the case of the glass door according to the invention

  Approximately 25% of the heat supplied passes into the cold room while about 75% of this heat passes into the store. This result is illustrated by the respective arrows 11 and 12 in the single figure. energy delivered escapes in the form of heat losses, the heat losses are thus reversed, which means that the refrigeration machine of the cold room is less loaded because the amount of energy it receives is less than that corresponding to the case of a door

in classic glass.

  From an economic point of view, it is obvious that the glass door according to the invention costs twice less

  expensive to heat, and that simultaneously the cooling costs

  The cooling chamber required for evacuating the energy supplied to the cold room is considerably reduced With a conventional door, the cold room receives about 72 to 96 watts / m 2 while with the door according to the invention, the cold room receives only about 28 to 32 watts / m If you consider the simultaneous reduction of

  the energy demanded from the refrigeration machine, the invention

  This saves a total of 73 to 130 watts per door.

  All that has been said above applies also

  good in cold rooms than in freezers.

  We can, of course, make changes

  cations to the invention by making the intermediate panels

  in another type of glass than window glass and outer panels in another type of glass

than tempered glass.

Claims (1)

R E V E N D I C A T IO N S   ) Glass door for freezers and cham-   in which the front panel (2) opposite the freezer and the cold room is heated by an electrically conductive layer attached to the inner surface of the panel, glass door (1) characterized by   it has four panels (2, 3, 4, 5) parallel to   to each other and sealed against each other   other, in a manner known per se by sealing joints   (8, 9, 10) placed along the edges of the panels.   Glass door according to claim 1, characterized in that the front panel (2) is heated with a maximum power of less than 50 watts / m