Method of optimising the performance of refrigerant vaporizers including improved frost control method and apparatus

Claim 3

The optimizing method in accordance with claim 1, characterized in that said vaporization temperature is measured by means of a temperature sensor coupled to a vaporizer tube.

Claim 4

The optimizing method in accordance with claim 1, characterized in that said first and second temperature difference values, said computed value and said comparison value are continuously formed and said expansion valve is periodically controlled.

Claim 5

The optimizing method in accordance with claim 1, characterized in that the control of the expansion valve (EV) is always effected when said comparison value lies outside of a predetermined tolerance range.

Claim 6

The optimizing method in accordance with claim 1, characterized in that during a phase of commencing use of the refrigerator device a periodic control used for control of the expansion valve differs from a periodic control used in normal operation.

Claim 7

The optimizing method in accordance with claim 1, characterized in that the expansion valve is positionable and includes an adjustable valve needle.

Claim 8

The optimizing method in accordance with claim 1, characterized in that a processing of said measured values and a formation of control signals for the expansion valve takes place in a computing unit which is provided with a specially prepared program.

Claim 9

The optimizing method of claim 1 wherein said vaporization temperature and said cooler outlet temperature measuring step is performed continuously.

Claim 10

The optimizing method of claim 1 wherein said vaporization temperature and said cooler outlet temperature measuring step is performed periodically.

Claim 11

The optimizing method of claim 1 wherein said difference measuring step measures said difference in degrees Kelvin.

Claim 12

The optimizing method of claim 10 wherein said factor is between about 0.6 and 0.7.

Claim 13

The optimizing method of claim 11 wherein said factor is about 0.625.

Claim 14

The optimizing method of claim 1 wherein said temperature comparing step is performed continuously.

Claim 15

The optimizing method of claim 1 wherein said temperature comparing step is performed periodically.

Claim 16

The optimizing method of claim 2 wherein said temperature sensor is coupled to said vaporizer tube about in a region one-half a length of said vaporizer tube.

Claim 17

The optimizing method of claim 6 wherein said positionable expansion valve is electrically positionable.

Claim 18

The optimizing method of claim 16 wherein said electrically positionable expansion valve is digitally controllable.

Claim 21

The operating method of claim 18 wherein said difference determining step determines said difference between said air supply temperature and said vaporization temperature in degrees Kelvin and said predetermined factor is between about 0.6 and 0.7.

Claim 22

The operating method of claim 19 wherein said predetermined factor is about 0.625.

Claim 23

A refrigerator, comprising: means for measuring a first temperature difference between and air inlet temperature of a refrigerator and a vaporization temperature of a refrigerant of said refrigerator; means, coupled to said first temperature measuring means, for computing a temperature value from said first temperature difference by multiplying said first temperature difference by a predetermined factor; means for measuring a second temperature difference between a vaporizer outlet temperature and said vaporization temperature; and means, coupled to said second temperature difference measuring means and to said computing means, for controlling a temperature of said refrigerant such that said second temperature difference approximately equals said computed temperature difference.

Claim 24

A refrigerator, comprising: means for measuring a first temperature difference between and air inlet temperature of a refrigerator and a vaporization temperature of a refrigerant of said refrigerator; means, coupled to said first temperature measuring means, for computing a temperature value from said first temperature difference by multiplying said first temperature difference by a predetermined factor; means for measuring a second temperature difference between a vaporizer outlet temperature and said vaporization temperature; and means, coupled to said second temperature difference measuring means and to said computing means, for controlling a temperature of said refrigerant such that said second temperature difference approximately equals said computed temperature difference.

Claim 25

Method of optimising the performance of refrigeration devices which are operated with a refrigerant and are fed via an expansion valve, in particular the performance of fan air refrigerators, in which, in addition to the air entry temperature or the supply air temperature (tL 1), both the vaporization temperature (t O ) and also the temperature at the air refrigerator outlet (t Oh ) are measured continuously or periodically and the difference value (δt l ) between the supply air temperature (tL 1) and the vaporization temperature (t O ) is determined, in which this difference value (δt 1 ) is multiplied by a factor between 0.6 and 0.7, and the computed temperature value which is obtained is compared with the difference value (δt oh ) of the temperature at the air refrigerator outlet (t oh ), and the vaporization temperature (t o ), and in which the expansion valve (EV) at the inlet side of the air refrigerator is then controlled continuously or periodically in dependence on the result of the comparison in such a way that the temperature at the vaporizer outlet (t Oh ) is at least substantially the same as the computed temperature value, characterized in that the difference value (δt 1 ) between the supply air temperature (tL 1) and the vaporization temperature (t O ) is monitored for the purpose of determining the ideal defrosting time point of the refrigeration device with respect to exceeding a predeterminable boundary value; in that, in the case of exceeding this boundary value, a compressor and fan are switched off and a defrosting heating device is switched in until the air refrigerator has reached a predeterminable temperature corresponding to the ice-free state; and in that the compressor is then switched on again and also the fan with a time delay relative to the compressor.

Claim 26

Method of optimising the performance of refrigeration devices which are operated with a refrigerant and are fed via an expansion valve, in particular the performance of fan air refrigerators, in which, in addition to the air entry temperature or the supply air temperature (tL 1), both the vaporization temperature (t O ) and also the temperature at the air refrigerator outlet (t Oh ) are measured continuously or periodically and the difference value (δt l ) between the supply air temperature (tL 1) and the vaporization temperature (t O ) is determined, in which this difference value (δt 1 ) is multiplied by a factor between 0.6 and 0.7, and the computed temperature value which is obtained is compared with the difference value (δt oh ) of the temperature at the air refrigerator outlet (t oh ), and the vaporization temperature (t o ), and in which the expansion valve (EV) at the inlet side of the air refrigerator is then controlled continuously or periodically in dependence on the result of the comparison in such a way that the temperature at the vaporizer outlet (t Oh ) is at least substantially the same as the computed temperature value, characterized in that the difference value (δt 1 ) between the supply air temperature (tL 1) and the vaporization temperature (t O ) is monitored for the purpose of determining the ideal defrosting time point of the refrigeration device with respect to exceeding a predeterminable boundary value; in that, in the case of exceeding this boundary value, a compressor and fan are switched off and a defrosting heating device is switched in until the air refrigerator has reached a predeterminable temperature corresponding to the ice-free state; and in that the compressor is then switched on again and also the fan with a time delay relative to the compressor.

Claim 27

Method in accordance with claim 22, characterized in that the switching on of the fan takes place when the vaporization temperature (t O ) has reached a predeterminable value.

Claim 28

Method in accordance with claim 22 characterized in that, in parallel to the monitoring of the difference temperature (δt 1 ), a monitoring of the refrigerant throughflow is effected with respect to a reduction of the throughflow which extends over a predeterminable time interval, and in that the switching on of the defrosting heating device takes place in dependence on both criteria.

Claim 29

Method in accordance with claim 22, characterized in that the switching on and switching off of the compressor is effected in dependence on the supply air temperature (tL 1) and a room thermostat function is thereby realised.

Claim 30

Apparatus for carrying the method in accordance with claim 22 comprising an air refrigerator (XL), an expansion valve (EV) arranged in the refrigerant supply line, temperature sensors for determining the supply air temperature (tL 1), the vaporization temperature (t O ) of the refrigerant and the overheating temperature (t Oh ) at the and of the air refrigerator, and also a computing unit for forming the setting values for the expansion valve, characterized in that a further temperature sensor is provided for the determination of the heating switch off temperature (T STB ) corresponding to an icefree state of the air refrigerator (KL) and is connected with the computing unit (KLR); in that signal values corresponding to the degree of opening or to an angle of opening of the expansion value (EV) form evaluatable parameters for the refrigerant throughflow in the computing unit (KLR); and in that the switching on and switching off of the air refrigerator (KL) and also of the fan are controlled via the computing unit (KLR).

Claim 31

Apparatus in accordance with claim 26, characterized in that a needle valve or ball valve controlled by a stepping motor is used as the expansion valve (EV); and in that the respective degree of opening of the expansion valve (EV) can be detected in the computing unit (KLR) by step counting procedures.

Claim 32

Apparatus in accordance with claim 26, characterized in that the comparison time interval for the change of the refrigerant throughflow can be set in the computing unit (KLR).

Claim 33

Apparatus in accordance with claim 26 characterized in that, for the provision of a room thermostat function, the signal delivered from the sensor for the supply air temperature (tL 1) is compared in the computing unit (KLR) with a predeterminable desired value and a switching signal for the compressor control is generated in dependence on the exceeding or falling short of a tolerance range related to this desired value.

Claim 34

Apparatus in accordance with claim 29, characterized in that the tolerance range associated with the desired value is adjustable.

Claim 35

Method of claim 22 wherein said factor is about equal to 0.625.