Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47F—SPECIAL FURNITURE, FITTINGS, OR ACCESSORIES FOR SHOPS, STOREHOUSES, BARS, RESTAURANTS OR THE LIKE; PAYING COUNTERS
  • A47F3/00—Show cases or show cabinets
  • A47F3/04—Show cases or show cabinets air-conditioned, refrigerated
  • A47F3/0439—Cases or cabinets of the open type
  • A47F3/0443—Cases or cabinets of the open type with forced air circulation
  • A47F3/0447—Cases or cabinets of the open type with forced air circulation with air curtains

Definitions

• the invention relates to a device for generating an air wall for thermal separation of the air in a relatively cold first space, i.e. the interior of a refrigerated cabinet, cold room or the like for the purpose of cooled self-service presentation of prepackaged cooled food products, from the air in the relatively warm second space, i.e.
• the device comprising: a primary blower slit connecting to a primary blower unit positioned close to a side of the frontal opening and disposed substantially parallel to the main plane of the frontal opening, which slit extends substantially over the whole relevant dimension of the frontal opening for the purpose of generating an at least more or less flat primary air stream directed at least roughly toward the opposite side of the frontal opening.
• Refrigerated cabinets for instance upright refrigerated wall cabinets, and cold rooms are often equipped with an air curtain which is cooled to a slight extent, wherein the air is supplied at the top and is extracted at the bottom in order to thus keep the temperature in the area of the shelves and the bottom at a determined temperature, for instance in the range of 0 0 C - 10 0 C.
• the passerby feels the cold air.
• the cold can often be felt in every limb in disagreeable manner .
• Another drawback is the associated energy loss.
• One of the causes of the energy loss is the cold usually flowing or leaking away on the underside of the air curtain. This is because the air curtain is not able to form a barrier against the cold layers accumulating at the bottom.
• Another cause of energy loss is formed by the air vortices caused by passers-by. Cold likewise leaks away as a result.
• a further adverse side-effect is formed by the occurrence of an external induction layer along the air curtain, with slow air stream downward from the top, and where warmer air is likewise entrained into the air curtain.
• the invention provides a device of the type stated in the preamble which has the feature that two secondary entrained air streams SsI and Ss2 are added to the primary air stream Sp on either side thereof, which secondary entrained air streams have substantially the same direction as the primary air stream;
• TsI the temperature of the secondary entrained air stream on the inside
• Ts2 the temperature of the secondary entrained air stream on the outside; the speed of the air in the primary air stream amounts to 2-30 m/s; the width of the primary blower slit lies in the range of 5-20 mm, preferably 8-15 mm; and the length of the blower slit in the direction of the air stream lies in the range of about 50-150 mm; this such that no mixing occurs between the primary air stream Sp and the two entrained secondary air streams SsI and Ss2.
• the frontal opening of the refrigerated cabinet must have single or multiple closure by one or more adapted air walls with an air stream formed by an air distributing box at the top along the length of the cabinet, with a narrow blower slit with a width in the range of about 5 to 30 mm, and wherein the air is forced to the air distributing box by two air guiding plates with a length in the flow direction of at least 10 cm. Between these two air guiding plates the air has a speed of 2-35 m/s.
• the air walls can thus be added to an existing cooled air cabinet, or the air wall can be built into the cooling circuit in the refrigerated cabinet.
• the device can have the special feature that the blower slit is divided into blower channels by partitions extending in the air stream direction.
• this aspect can be technically particularly significant. It is noted in general that the invention is intended for application in combination with refrigerated cabinets or cold rooms. It must therefore be understood that everywhere the word ⁇ refrigerated cabinet' is used, this also includes ⁇ cold room' .
• figure 1 shows a vertical section through a known refrigerated cabinet with an air curtain and an entrained secondary air stream
• figure 2 shows a section corresponding to figure 1 to which an air distributing box is added as device according to the invention
• figure 3 shows an auxiliary device according to the invention, intended for addition to an existing refrigerated cabinet
• figure 4 shows a vertical section through a device according to the invention which generates two air walls
• figure 5 shows a view corresponding to figure 3 of an auxiliary device as according to figure 4
• figure 6 shows a vertical section through a device similar to the device according to figure 2, but wherein the relevant air streams behave partly according to the Coanda effect
• figure 7 shows a vertical section of an arrangement similar to that according to figure 4, but wherein the entrained secondary air stream is drawn in and circulated
• figure 8 shows a vertical section through a refrigerated cabinet with a device according to the invention in yet another embodiment
• figure 9 shows a vertical section through an arrangement according to figure 8, but with a cooled inner circuit and an
• Figure 1 shows an upright refrigerated wall cabinet 22 which is provided with means for generating an air curtain 1 consisting of a more or less flat primary air stream with a small thickness and a high flow rate of 2- 30 m/s.
• Reference numeral 2 designates the entrained secondary air stream acting on the outside. The air in the entrained secondary air stream 2 is cooled considerably as a result of the low flow rate of both air curtain 1 and entrained stream 2. The cooled air tends to accumulate to some extent in the area designated with 3 on the front side of cabinet 22 close to floor 23.
• the interior space of refrigerated wall cabinet 22 comprises a number of shelves, designated with reference numeral 4, for holding the food products to be presented for sale.
• the cabinet further comprises an evaporator 5 and a fan 6 for cooling the air flowing by, which circulates in a more or less closed circuit in the manner shown in figure 1.
• FIG. 2 shows an upright refrigerated wall cabinet 28, the basic configuration of which corresponds to the structure according to figure 1.
• an air distributing box 29 is added to said cabinet, this box being adapted to generate an air wall in the form of a rapid (2-30 m/s) air stream 30 of small thickness (initial thickness 5-20 mm) , which is situated on the outside relative to slow air curtain 1.
• Air distributing box 29 comprises a fan 31 which draws in air wall 30 on the underside via an air duct 8 and blows it out again via a primary blower slit 32 such that a more or less closed circuit is formed.
• the speed of the air in this primary air stream 30 amounts to about 15 to 20 m/s.
• the width of blower slit 32 in the plane of the drawing is in the order of magnitude of 10- 12 mm. Its length in the flow direction lies in the range of about 50-150 mm.
• the entrained secondary flow on the outside is designated with reference numeral 2' in order to distinguish it from the entrained air stream 2 according to figure 1, which does after all flow substantially more slowly.
• Figure 4 shows the configuration according to figure 2, but with an extension formed by an additional forced secondary outer stream 9 which forms part of an additional more or less closed air circuit.
• the flows of respectively air curtain 1, primary air stream 30, secondary air stream 9 and the outer entrained secondary air stream 2 move substantially parallel to each other in the area of opening 34 of cabinet 22.
• the effective thermal insulation in the area of shelves 4 in cabinet 22, which can be expressed as the heat resistance between the relatively warm exterior space and the relatively warm interior space, will thus be even greater in the configuration according to figure 4, which is already better than in the configuration according to figure 2.
• Figure 5 shows that the multiple air distributing box 35 not only comprises the fan 31 for primary air stream 30, but also an additional fan 36 for the outer secondary fan.
• FIG. 6 shows a configuration in which a refrigerated cabinet 37 is also provided with a lighting fixture 11.
• air curtain 1 departs from its normal linear path as a result of the suction of an induction air stream by primary air stream 30 according to the teaching of the invention.
• There is therefore a dual effect i.e. on the one hand the suction as entrained air stream and on the other hand the Coanda effect, wherein air curtain 1 begins to behave as such an air stream. Since the configuration otherwise corresponds to that according to figure 2, the description of the other components is omitted here.
• Figure 7 shows a configuration wherein the second entrained air stream 10 is drawn in and circulated together with the first entrained air stream 9.
• the quantity of air which is drawn in on the underside must be discharged via an air outlet 12 such that the balance is guaranteed.
• Figure 8 shows a configuration wherein the air is cooled by an evaporator 5 placed in the top part of the cabinet together with an associated pressure fan 13. Cold air is carried downward via an adjustable opening 14 for the purpose of cooling the food products held by shelves 4.
• Figure 9 shows a configuration which is related to that according to figure 8 but which has a cooled inner circuit, comprising an evaporator 38 and a fan 39, both of which are arranged on the top side.
• Figure 10 shows a configuration with an upright cooled refrigerated wall cabinet, according to which configuration the primary stream in the air wall according to the invention flows upward from the bottom.
• the entrained secondary air stream 16 flowing on the inside also flows upward, whereby the possible “falling” cold air likewise flows upward.
• This air stream then passes the static evaporator 17.
• the cooled air coming from evaporator 17 automatically moves downward and reaches the space with shelves 4 via openings 27.
• the pressure fan 13 is drawn on the underside. There is no technical reason for this per se; it could be placed on the top side with the same effect.
• the entrained secondary air stream 18 situated on the outside also moves upward. At the top this air can be used to cool the condenser of a cooling group 19 placed there.
• the COP of the installation is hereby increased even further.
• Figure 11 shows a configuration which can be deemed a variant of the configuration according to figure 10.
• a ventilated evaporator 5 with a low-pressure fan 6 is applied instead of static evaporator 17.
• the closed air circuit takes roughly the same form as in the configuration according to figure 10.
• Figure 12 shows an arrangement wherein an air distributing box 29 according to figure 3 connects substantially to wall 40 of a cold room 41 adjoining a retail space 42.
• An entrained secondary outer air stream 20 also results in the manner shown in this embodiment.
• Figure 13 shows a variant of the arrangement according to figure 12, in which is shown schematically that an outer entrained air stream 21 forms part of a closed circuit, comprising a blower unit 43 on the top side, a suction unit 44 on the underside, this suction unit being connected to the blower unit via a schematically drawn bypass 46 with a fan 45.
• Figure 14 shows schematically a variant with an air wall, which is based on a rapid, thin primary air stream 30 according to the invention, in the entrance opening of a cold room 41 adjoining a retail space 42, which flow 30 moves upward.
• the arrangement is closely related to that according to figures 10 and 11. This relation is also manifest in the shown pattern of secondary streams 16 and 18.
• Figure 16 shows a front view of a refrigerated cabinet with a device according to the invention, which is provided with shelves 4 for holding products to be presented for sale.
• the air wall can be applied in single arrangement to thermally separate the relatively warm ambient air from the relatively cold air in the interior of a refrigerated cabinet or cold room. If the temperature difference over this single air wall is small, there will be little heat loss.
• the elongate lighting fixture may then be in the way. In this case it is possible to remove the lighting unit, position the outlet of the air distributing box there, and subsequently place the lighting unit thereon. It is usually necessary in this case to ensure that the direction of the air blower slit is adjustable, namely such that the primary air stream exits at the bottom edge of the cabinet. The intention here is to separate the cooled internal air stream circuit from the air wall.
• a refrigerated cabinet can suffice with a smaller cooling installation and therefore be cheaper.
• the invention can also be applied when selling from cold rooms . 8)
• the structure according to the invention can also be applied in the case where a lighting fixture is situated inside the cooled space.

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• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Cold Air Circulating Systems And Constructional Details In Refrigerators (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2009
  • 2009-03-09 EP EP09719120A patent/EP2257202A2/de not_active Withdrawn
  • 2009-03-09 WO PCT/NL2009/050109 patent/WO2009113848A2/en not_active Ceased
  • 2009-03-09 US US12/736,087 patent/US20110314857A1/en not_active Abandoned
  • 2009-03-09 NL NL2002604A patent/NL2002604C2/nl not_active IP Right Cessation
  • 2009-03-09 CN CN200980108316XA patent/CN101965141B/zh not_active Expired - Fee Related

Non-Patent Citations (1)

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