Ventilation Unit for a Freezer Chamber

Abstract

A ventilation unit for a freezer chamber, with a conduit and at least one heating element, wherein in the conduit, at least in sections, an air-permeable filler material is disposed, as well as a freezer chamber with such a ventilation unit as well as methods for operating such ventilation unit.

Claims

1. A ventilation unit for a freezer chamber, comprising: a conduit; a heating element; and an air-permeable filler material disposed in at least sections of the conduit.

2. The ventilation unit as in claim 1, wherein the heating element is disposed on the conduit.

3. The ventilation unit as in claim 1, wherein the filler material is a knit wire mesh.

4. The ventilation unit as in claim 1, wherein the heating element is formed by the filler material.

5. The ventilation unit as in claim 1, wherein the conduit comprises a filler material securement element.

6. The ventilation unit as in claim 5, wherein the securement element is a pin or a tongue.

7. The ventilation unit as in claim 6, wherein the tongue has a contour cut out from a wall of the conduit, and the tongue is bent at a non-cut-out section into a cross section of the conduit.

8. A freezer, comprising: a housing having an interior volume and a door; a ventilation unit, wherein the ventilation unit comprises: a conduit; and a heating element; an air-permeable filler material disposed in at least sections of the conduit.

9. The freezer chamber as in claim 8, wherein the ventilation unit is disposed in the door and/or in the housing such that a first end of the conduit opens out into the interior volume and a second end of the conduit opens out into a work environment.

10. The freezer chamber as in claim 8, wherein the heating element is activatable by opening the door.

11. The freezer chamber as in claim 8, wherein the heating element is deactivatable after a passage of a specific time interval after the door is closed.

12. A method for operating a ventilation unit, comprising: providing a freezer with a housing having an interior volume and a door and a ventilation unit, wherein the ventilation unit comprises: a conduit; and a heating element; an air-permeable filler material disposed in at least sections of the conduit chamber with a conduit; detecting the door being opened; activating the heating element based on detecting the door being opened; detecting the door being closed; deactivating the heating element based on a passage of a specific time interval after the door is closed.

13. The method for operating a ventilation unit as in claim 12, further comprising determining the specific time interval based on a temperature difference and/or a pressure differential between the interior volume and the work environment.

14. The method for operating a ventilation until as in claim 12, further comprising determining the specific time interval based on an interval of elapsed time since a last deactivation of the heating element and/or a last heating duration between a last activation and deactivation of the heating element.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0035] Embodiment examples of the present application will be explained in conjunction with the following Figures. Therein depict:

[0036] FIG. 1 a schematic representation of an embodiment example of a ventilation unit disposed in a door,

[0037] FIG. 2 a schematic representation of an embodiment example of a conduit,

[0038] FIG. 3 a schematic representation of a further embodiment example of a conduit,

[0039] FIG. 4 a schematic representation of an embodiment example of an ultra low freezer chamber with a ventilation unit,

[0040] FIG. 5 a flowchart of a first method for operating a ventilation unit in an ultra low freezer chamber,

[0041] FIG. 6 a flowchart of a second method for operating a ventilation unit in an ultra low freezer chamber.

DETAILED DESCRIPTION

[0042] For same and functionally same parts same reference numbers are used. For the sake of clarity not all reference numbers are used in every Figure.

[0043] FIG. 1 shows a ventilation unit or device 10 disposed in a door 44, with a conduit 20 and a heating element 30. In the conduit 20 is disposed an air-permeable filler material which can be developed as a knit wire mesh 12.

[0044] The specified normal operation of the ventilation unit 10 preferably lies in equalizing a pressure differential 82 (s. FIG. 3) between two volumes, in particular between an interior volume 46 and a work environment 50 (s. FIG. 2). For this purpose, through the conduit 20 there can be an air can flow. For this purpose the conduit 20 preferably has a direction of throughflow 28.

[0045] FIG. 4 shows a freezer chamber developed as an ultra low freezer chamber 40 with a ventilation unit 10. When the ventilation unit 10 is deployed in the ultra low freezer chamber 40, the conduit 20 and the knit wire mesh 12 disposed therein can ice over under the temperatures obtaining in the ultra low freezer chamber 40. The icing over takes place, for example, thereby that water condenses out of the air and freezes. Due to the icing over the cross section of the conduit 20 can decrease or can even become completely blocked. For the complete blocking of the conduit 20 thus preferably an ice plug is disposed in the conduit 20. An air stream through the ventilation unit 10 can therewith be decreased or be completely disrupted. This effect can be intentional, in particular, for the purpose of preventing undesirable air flows through the ventilation unit 10 and be enhanced through the disposition of the knit wire mesh 12 in the conduit 20. By activating the heating element 30 the de-icing, thus opening, or, as the case may be, the maintaining of the ventilation unit 10 ice-free, thus keeping it open, can be achieved.

[0046] FIG. 1 shows further details of the ventilation unit 10. The conduit 20 thus preferably comprises a first end 22, a second end 24 as well as a longitudinal conduit axis 26. The conduit 20 can be developed straight or comprise at least one curvature. The conduit 20 is preferably fabricated of a material, in particular of a metal material, having high thermal conductivity. Due to the high thermal conductivity in particular rapid de-icing of the ventilation unit 10 can be enabled. The conduit 20 can, for example, have a round cross section 98 (FIG. 2) or a square cross section 99 (FIG. 3).

[0047] The knit wire mesh 12 is preferably disposed in the conduit 20 such that it completely fills the cross section of conduit 20. The knit wire mesh 12 is herein preferably a three-dimensional wire structure in which are disposed interspaces between the individual wires or wire strands. On the wires or wire strands as well as on the conduit 20 water can condense out of the air. The interspaces are denoted as cells and can ensure the air permeability of the knit wire mesh 12. The size of the cells herein is preferably selected to be small enough for the cells to freeze up through the water that is condensed on the knit wire mesh 12. The size of the cells is preferably simultaneously selected such that when the cells are open, thus not frozen up, a sufficiently large air through-put through the knit wire mesh 12 is enabled.

[0048] The knit wire mesh 12 can be developed such that it is elastic. It can, in particular, be developed as a spongy formation. The elasticity of the knit wire mesh 12 can, in particular, be regulated by the size of the cells and the thickness of the utilized wire strands. A knit wire mesh 12 of wire strands with reduced thickness can be especially advantageous for deployment in a ventilation unit 10 since therewith a very fine cell structure can be created.

[0049] The heating element 30 can be developed as an electric heating element. The heating element 30 is herein preferably supplied with energy across a cable 32. The heating element 30 is preferably disposed on the outside of conduit 20 in the circumferential direction about the conduit 20. With the activation of the heating element 30 the conduit 20 can therewith be heated from the outside. The heat can be introduced across conduit 20 into the knit wire mesh 12. The heating element 30 is herein preferably disposed in that section of the conduit 20 in which the knit wire mesh 12 is disposed. In this way the conduction path of heat from heating element 30 to the knit wire mesh 12 can thereby be kept short. The time delay between the activation of the heating element 30 and the heating of the knit wire mesh 12 can thereby be kept low. In this manner, dynamic heating of the knit wire mesh 12 can be realized. Therewith the time delay between the activation of the at least one heating element 30 and the opening of the cells can also be minimized.

[0050] The conduit 20 preferably comprises a securement element in the form of a pin 18 for securing the knit wire mesh 12. With the aid of the pin 18 displacement, caused in particular by air flows in the conduit 20, of the knit wire mesh 12 can be avoided. For this purpose, pin 18 is preferably disposed downstream of the knit wire mesh 12 in the throughflow direction 28. Pin 18 can establish a connection under form closure between the knit wire mesh 12 and the conduit 20. The pin 18 is for this purpose preferably disposed transversely to the longitudinal conduit axis 26 and disposed in a bore extending transversely to the longitudinal conduit axis 26.

[0051] FIG. 2 and FIG. 3 show embodiment examples of a conduit 20 in which the securement is formed by a tongue 90. The tongue 90 is preferably formed thereby that a contour of tongue 90 is, at least in sections, cut out of a wall 21 of conduit 20 such that the contour comprises a cut-out section 96. Tongue 90 can be bent at a non-cut-out section 94 of the contour in the direction of bending 92 into the cross section of conduit 20. The non-cut-out section 94 is herein preferably developed such that it is perforated in order to facilitate the inward bending. The cutting can be carried out using, in particular, lasering or die cutting. By the development as a tongue 90 the securement element can be produced especially cost-effectively.

[0052] The depiction in FIG. 2 shows the conduit 20 in a fabrication step in which the tongue 90 has already been cut out, however, has not yet been bent into the cross section of conduit 20.

[0053] FIG. 3 shows a conduit 20 in which the tongue 90 has been bent into the cross section of conduit 20.

[0054] In FIG. 4 further details of the ultra low freezer chamber 40 are depicted. The ultra low freezer chamber 40 preferably has a control range from −90° C. to −40° C. The ultra low freezer chamber comprises a housing 42 in which the interior volume 46 is disposed. The ultra low freezer chamber 40 furthermore comprises a door 44 as well as the ventilation unit 10. As interior volume 46 is, in particular, denoted that volume which, with the door 44 closed, is encompassed by the housing 42 and the door 44.

[0055] The ventilation unit 10 is preferably disposed in the door 44 such that, when the door 44 is closed, the first end 22 of conduit 20 empties out into the interior volume 46 and a second end 24 of conduit 20 empties out into the work environment 50. The work environment 50 is preferably formed by that volume which is located outside of the ultra low freezer chamber 40.

[0056] The temperature in the interior volume 46 is conventionally below the temperature in the work environment 50. The conduit 20 can be iced over and therewith be blocked by an ice plug. The ice plug is preferably formed by water that has condensed on the knit wire mesh 12. The work environment 50 and the interior volume 46 can consequently be separated through the housing 42 and the door 44 of the ultra low freezer chamber 40.

[0057] In particular when the interior volume 46 is separated from the work environment 50 a pressure differential 82 can occur between interior volume 46 and work environment 50. This is typically the case when, due to temporary opening of door 44, warm air from the work environment 50 has penetrated into the interior volume 46. The air is conventionally cooled here whereby its volume decreases and the pressure in the interior volume 46 drops in comparison to the work environment 50. Thus, there is typically a correlation between the opening of the door 44 and the generation of a pressure differential 82. A pressure differential 82 can be equalized thereby that air can flow from the work environment 50 into the interior volume 46.

[0058] Thereby that conduit 20 with its first end 22 opens out into the interior volume 46 and with its second end 24 opens out into the work environment 50, the ventilation unit 10 can establish a connection between interior volume 46 and work environment 50. The connection is preferably established thereby that the heating element 30 is activated and therewith the ice plug is thawed and the ventilation unit 10 is opened. Air can thereby flow into the interior volume 46. Based on the typical pressure gradient, preferably a throughflow direction 28 of the conduit 20 from the work environment 50 toward the interior volume 46 results. The blocking of conduit 20 preferably takes place by deactivating the heating element 30. In particular, the conduit 20 and the knit wire mesh 12 of ventilation element unit 10 can consequently be cooled by the low temperatures obtaining in the interior volume 46. Therewith on the conduit 20 and the knit wire mesh 12 water can condense out of the air and forms a new ice plug.

[0059] The heating element 30 is preferably activatable through the opening of door 44. The ultra low freezer chamber 40 can comprise an opening sensor 48 that can detect the opening of door 44. The heating element 30 is preferably deactivatable after a specific time interval 66 (s. FIGS. 3 and 4) after the closure of the at least one door 44 has elapsed.

[0060] FIG. 5 shows a flowchart of a first method for operating the ventilation unit 10 in the ultra low freezer chamber 40. Due to the detection 60 of the opening of door 44, herein an activation 62 of the heating element 30 takes place. After subsequently again a detection 64 of the closing of door 44 has taken place, a deactivation 68 of heating element 30 is carried out after the specified time interval 66 has elapsed.

[0061] The activation 62 of heating element 30 preferably takes place without time delay with the detection 60 of the opening of door 44. It can thereby be achieved that the ventilation device unit 10 is opened at a subsequent closing of door 44 such that pressure equalization between work environment 50 and interior volume 46 can take place. Therewith the factor can be taken into account that typically there exists a correlation between the opening of door 44 and the development of a pressure differential 82 between the interior volume 46 and the work environment 50.

[0062] The length of time interval 66 is preferably chosen to be such that the pressure differential 82, generated by the opening and closing of door 44, between work environment 50 and interior volume 46 is equalized after the closing of door 44. With the aid of time interval 66 herein in particular the factor can be taken into account that the pressure differential 82 after the closing of door 44 does not manifest immediately in its full magnitude after the closing of door 44 but rather shows progression over time.

[0063] The ultra low freezer chamber 40 can be developed such that the time interval 66 can be defined by presetting. A value of three minutes has herein been found to be especially advantageous. The time interval 66 can further be determined or influenced by drawing on data entered at the operator side and/or on data determined by means of sensors. Such data can be the pressure differential 82 and/or a temperature difference 80 between interior volume 46 and work environment 50. Large pressure differentials 82 and/or temperature differences 80 preferably extend the time interval 66. At low pressure differentials 82 and/or low temperature differences 80 the method can be modified such that the time interval 66 is shortened correspondingly.

[0064] As shown in FIG. 6, in determining the time interval 66 of a current opening cycle 110, reference can be made to a last completed one, thus to a last opening cycle 100. For example, into the determination of the time interval 66 can be incorporated a time interval 70, elapsed since the last deactivation 68 of the heating element 30, and/or a last heating duration 72 between the last activation 62 and deactivation 68 of the heating element 30. Heating of ventilation unit 10 during time interval 66 serves preferably for the purpose of keeping the ventilation unit 10 sufficiently long open, thus free of ice, after the closing of door 44 in order to enable the pressure equalization. If the last activity of the heating element 30 was sufficiently recent, residual heat can still be available in the ventilation unit 10 which can support keeping open the ventilation unit 10. There is usually more residual heat available the more recent the last activity of the heating element 30 occurred, thus the shorter the time interval 70 is. The operation of the ventilation unit 10 can therefore be developed such that a short interval time 70 enables a shortening of the time interval 66 of the current opening cycle 110. The duration of the last activity of heating element 30, the last heating duration 72, can also provide an indication of the magnitude of residual heat that is available in the ventilation unit 10. The method is therefore preferably developed such that a long last heating duration 72 exerts a shortening effect onto the time interval 66.

[0065] The method for operating the ventilation unit 10 can, in particular, be developed as a combination of the first method, depicted in FIG. 5, and of the second method, depicted in FIG. 6, such that the temperature difference 80 and/or the pressure differential 82 as well as also the interval time 70 and/or the last heating duration 72 are taken into consideration in determining the time interval 66.

LIST OF REFERENCE NUMBERS

[0066] 10 Ventilation unit [0067] 12 Knit wire mesh [0068] 18 Pin [0069] 20 Conduit [0070] 21 Wall [0071] 22 First end [0072] 24 Second end [0073] 26 Longitudinal conduit axis [0074] 28 Through flow direction [0075] 30 Heating element [0076] 32 Cable [0077] 40 Ultra low freezer chamber [0078] 42 Housing [0079] 44 Door [0080] 46 Interior volume [0081] 48 Opening sensor [0082] 50 Work environment [0083] 60 Detection of door opening [0084] 62 Activation of heating element [0085] 64 Detection of door closing [0086] 66 Time interval [0087] 68 Deactivation of heating element [0088] 70 Interval time [0089] 72 Last heating duration [0090] 80 Temperature difference [0091] 82 Pressure differential [0092] 90 Tongue [0093] 92 Bending direction [0094] 94 Non-cut-out section [0095] 96 Cut-out section [0096] 98 Round cross section [0097] 99 Rectangular cross section [0098] 100 Last opening cycle [0099] 110 Current opening cycle