Refrigerator fan device and ultra-low temperature freezer

1. A refrigerator fan device, comprising:

a fan motor ( 10 ) which has a fan rotor ( 12 ), the fan motor being provided in an air duct along with a refrigerator heat exchanger ( 15 ) or a refrigerator compressor ( 14 ), the fan motor being positioned in the air duct between an air inlet ( 16 ) and an air outlet ( 18 ) on a refrigerator ( 20 ) or in a bottom area ( 22 ) of a refrigerator housing,

said fan motor ( 10 ) being connected to a unit of the refrigerator via electrical supply or control lines, wherein the fan motor ( 10 ) is a brushless speed-controllable DC motor whose operating speed is controlled such that when the refrigerator compressor ( 14 ) is in a stationary operation, the operating speed of the fan motor ( 10 ) is reduced as compared to a fan speed during cooling down of a used cooling space by the refrigerator compressor ( 14 ), wherein the stationary operation is defined as operation when a temperature in the used cooling space is within a range of a target cooling temperature and a time derivative of the temperature is equal to or lower than a predetermined threshold, and

wherein the temperature is shown by an operating temperature signal or a used cooling space temperature signal, the operating temperature signal showing the temperature of the refrigerator compressor ( 14 ).

2. The device according to claim 1 , further comprising temperature sensor means ( 26 ) which are assigned to a used cooling space of the refrigerator to generate the operating temperature signal or the used cooling space temperature signal.

3. The device according to claim 2 , wherein the temperature sensor means ( 26 ) are assigned to compressor control electronics ( 30 ) for controlling operation of the refrigerator compressor.

4. The device according to claim 3 , wherein the motor electronics have means for voltage conversion ( 38 ) of an applied supply network AC voltage into an intermediate DC voltage factor correction, the intermediate DC voltage being wired for generating the DC operating voltage for the fan motor.

5. The device according to claim 1 further comprising speed-detection or monitoring means ( 32 ) which are assigned to the fan motor ( 10 ) and which are configured, regarding a predetermined or predeterminable ratio or ratio range of the operating speed in relation to the operating or used cooling space temperature, to detect or display a malfunction in response to said ratio exceeding or falling short of a ratio threshold.

6. An ultra-low temperature refrigerator ( 20 ) having at least one refrigerator compressor ( 14 ) and the refrigerator fan device according to claim 1 assigned to the refrigerator compressor and to a cooling circuit heat exchanger ( 15 ) of the refrigerator, the ultra-low temperature refrigerator having a voltage supply unit ( 38 ) designed to be connected to a public power supply network and configured for a mains AC voltage between 85 V and 264 V, as a nominal mains AC voltage and providing an operating DC voltage for the refrigerator fan device.

7. The refrigerator according to claim 6 , wherein the refrigerator fan device is designed and configured such that in a cooling mode of the refrigerator at a target cooling temperature of the used cooling space to be cooled, the operating speed of the fan motor is reduced as compared to a fan speed during cooling down of the used cooling space by the refrigerator compressor and has been or is reduced continuously or according to a preferred proportional control curve.

8. The device according to claim 1 , wherein said fan motor ( 10 ) is connection to the refrigerator compressor or the refrigerator control electronics.

9. The device according to claim 4 , wherein the motor electronics further comprise means for power factor correction.

10. The refrigerator according to claim 6 , wherein the mains AC voltage is between 100 V and 230 V.

11. A refrigerator fan device, comprising:

a fan motor ( 10 ) which has a fan rotor ( 12 ), the fan motor being provided in an air duct along with a refrigerator heat exchanger ( 15 ) or a refrigerator compressor ( 14 ), the fan motor being positioned in the air duct between an air inlet ( 16 ) and an air outlet ( 18 ) of a refrigerator housing ( 20 , 22 ),

said fan motor ( 10 ) being connected to a unit of the refrigerator, via electrical supply or control lines,

wherein the fan motor ( 10 ) is a brushless speed-controllable DC motor whose operating speed is controlled as a function of an operating or used cooling space temperature signal of the assigned refrigerator compressor, wherein a DC operating voltage for the fan motor is generated by or derived from motor electronics ( 38 ) that are assigned to the refrigerator compressor, and

further comprising delay means which act on the assigned refrigerator compressor and which are configured such that in response to an activation signal which activates the refrigerator ( 20 ) or operation start signal which starts an operation of the refrigerator compressor ( 14 ), the fan motor is activated a predetermined time interval prior to activation of the refrigerator compressor.

12. The device according to claim 11 , wherein the delay means are configured or designed such that the predetermined time interval is between 1 s and 360 s.

13. The device according to claim 12 , wherein the predetermined time interval is between 2 s and 30 s.

14. The device according to claim 12 , wherein the predetermined time interval is between 3 s and 10 s.