US6047557A — Adaptive control for a refrigeration system using…

Claim 1

Independent Claim 160 words

A compressor control system, comprising: a compressor that is selectively operable while energized in at least two states, said compressor comprising a pair of fluid compressing members and including a first state corresponding to a first capacity wherein said pair of fluid compressing members are separated by a seal and a second state corresponding to a second capacity lower than said first capacity wherein said seal between said pair of fluid compressing members is broken; a load sensor for sensing a property indicative of demand for cooling; a controller coupled to said load sensor for producing a variable duty cycle control signal in which the duty cycle is a function of demand for cooling; said controller being coupled to said compressor for causing said compressor to selectively alternate between said first and second states in response to said variable duty cycle control signal, thereby adjusting the capacity of said compressor to the demand for cooling while said compressor is energized.

Claim 2

Dependent Claim 160 words

A compressor control system, comprising: a compressor that is selectively operable while energized in at least two states, said compressor comprising a pair of fluid compressing members and including a first state corresponding to a first capacity wherein said pair of fluid compressing members are separated by a seal and a second state corresponding to a second capacity lower than said first capacity wherein said seal between said pair of fluid compressing members is broken; a load sensor for sensing a property indicative of demand for cooling; a controller coupled to said load sensor for producing a variable duty cycle control signal in which the duty cycle is a function of demand for cooling; said controller being coupled to said compressor for causing said compressor to selectively alternate between said first and second states in response to said variable duty cycle control signal, thereby adjusting the capacity of said compressor to the demand for cooling while said compressor is energized.

Claim 3

Dependent Claim 39 words

The control system of claim 1 wherein said compressor pumps a refrigerant under pressure and wherein said controller produces said variable duty cycle control signal with a variable cycle time that is a function of fluctuations in refrigerant pressure.

Claim 4

Dependent Claim 14 words

The control system of claim 1 wherein said load sensor is a temperature sensor.

Claim 5

Dependent Claim 14 words

The control system of claim 1 further comprising pressure sensor coupled to said controller.

Claim 6

Dependent Claim 23 words

The control system of claim 1 wherein said load sensor is a temperature sensor and further comprising pressure sensor coupled to said controller.

Claim 7

Dependent Claim 54 words

The control system of claim 1 wherein said load sensor senses a property having a first rate of change and wherein said control system further comprising second load sensor that senses a second property having a second rate of change, said second rate of change being substantially greater than said first rate of change.

Claim 8

Dependent Claim 24 words

The control system of claim 6 wherein said load sensor senses changes in temperature and wherein said second load sensor senses changes in pressure.

Claim 9

Dependent Claim 35 words

The control system of claim 1 wherein said compressor includes fluid compressing members and mechanism for selectively rendering said compressing members effective and ineffective to thereby assume said first state and said second state, respectively.

Claim 10

Dependent Claim 32 words

The control system of claim 1 wherein said compressor includes an electric motor and wherein said compressor is configured such that said electric motor remains energized in said first and second states.

Claim 11

Dependent Claim 68 words

The control system of claim 1 wherein said compressor has two mechanical elements separated by a seal, said mechanical elements being movable relative to one another to develop fluid pressure and wherein said compressor includes mechanism to selectively break said seal in response to said control signal to thereby alter said fluid pressure developed while allowing said mechanical elements to maintain substantially constant relative movement with one another.

Claim 12

Dependent Claim 13 words

The control system of claim 1 wherein said compressor is a scroll compressor.

Claim 13

Dependent Claim 21 words

The control system of claim 10 wherein said compressor is a scroll compressor and said two mechanical elements are scroll members.

Claim 14

Dependent Claim 30 words

The compressor control system of claim 1 wherein controller provides said variable duty cycle control signal that cycles at a cycle time shorter than the time constant of the load.

Claim 15

Dependent Claim 29 words

The compressor control system of claim 1 wherein said first state is substantially at one hundred percent capacity and wherein said second state is substantially at zero percent capacity.

Claim 16

Dependent Claim 62 words

The compressor control system of claim 1 further comprising: a diagnostic module coupled to said controller for monitoring and comparing said duty cycle with at least one predetermined fault value indicative of a system fault condition; and an alert module responsive to said diagnostic module for issuing an alert signal when said duty cycle bears a predetermined relationship to said fault value.

Claim 17

Dependent Claim 105 words

A refrigeration system comprising, a refrigeration case; an evaporator disposed in said case; a condenser and compressor coupled in fluid communication with said evaporator; said condenser being disposed on said case and having means for transferring heat to ambient; said compressor comprising a pulse width modulated variable capacity compressor; a load sensor disposed in said case; a controller responsive to said load sensor and coupled to said compressor for providing a variable duty cycle control signal to said compressor for modulating said compressor between a sealed state and an unsealed state to thereby adjust the operating capacity of the refrigeration system to its thermal load.

Claim 18

Dependent Claim 105 words

A refrigeration system comprising, a refrigeration case; an evaporator disposed in said case; a condenser and compressor coupled in fluid communication with said evaporator; said condenser being disposed on said case and having means for transferring heat to ambient; said compressor comprising a pulse width modulated variable capacity compressor; a load sensor disposed in said case; a controller responsive to said load sensor and coupled to said compressor for providing a variable duty cycle control signal to said compressor for modulating said compressor between a sealed state and an unsealed state to thereby adjust the operating capacity of the refrigeration system to its thermal load.

Claim 19

Dependent Claim 29 words

The refrigeration system of claim 16 further comprising a second refrigeration case having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said condenser.

Claim 20

Dependent Claim 29 words

The refrigeration system of claim 16 further comprising a second refrigeration case having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said compressor.

Claim 21

Dependent Claim 14 words

The refrigeration system of claim 16 wherein said load sensor is a temperature sensor.

Claim 22

Dependent Claim 29 words

The refrigeration system of claim 16 wherein said controller produces said variable duty cycle control signal with a variable cycle time that is a function of fluctuations in pressure.

Claim 23

Dependent Claim 14 words

The refrigeration system of claim 16 further comprising pressure sensor coupled to said controller.

Claim 24

Dependent Claim 38 words

The refrigeration system of claim 16 further comprising refrigerant regulator valve coupled in fluid communication with said evaporator and being electrically controlled by said variable duty cycle control signal to further adjust the capacity of said refrigeration system.

Claim 25

Dependent Claim 13 words

The refrigeration system of claim 22 wherein said valve includes a stepper motor.

Claim 26

Dependent Claim 30 words

The compressor control system of claim 16 wherein controller provides said variable duty cycle control signal that cycles at a cycle time shorter than the time constant of the load.

Claim 27

Dependent Claim 29 words

The compressor control system of claim 16 wherein said first state is substantially at one hundred percent capacity and wherein said second state is substantially at zero percent capacity.

Claim 28

Dependent Claim 104 words

A cooling system comprising, a housing; an evaporator disposed in said housing; a condenser and compressor coupled in fluid communication with said evaporator; said condenser being disposed on said housing and having means for transferring heat to ambient; said compressor comprising a pulse width modulated variable capacity compressor; a load sensor disposed in said case; a controller responsive to said load sensor and coupled to said compressor for providing a variable duty cycle control signal to said compressor for modulating said compressor between a sealed state and an unsealed state to thereby adjust the operating capacity of the cooling system to its thermal load.

Claim 29

Dependent Claim 104 words

A cooling system comprising, a housing; an evaporator disposed in said housing; a condenser and compressor coupled in fluid communication with said evaporator; said condenser being disposed on said housing and having means for transferring heat to ambient; said compressor comprising a pulse width modulated variable capacity compressor; a load sensor disposed in said case; a controller responsive to said load sensor and coupled to said compressor for providing a variable duty cycle control signal to said compressor for modulating said compressor between a sealed state and an unsealed state to thereby adjust the operating capacity of the cooling system to its thermal load.

Claim 30

Dependent Claim 28 words

The cooling system of claim 26 further comprising a second housing having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said condenser.

Claim 31

Dependent Claim 28 words

The cooling system of claim 26 further comprising a second housing having a second evaporator disposed therein, said second evaporator being coupled in fluid communication with said compressor.

Claim 32

Dependent Claim 14 words

The cooling system of claim 26 wherein said load sensor is a temperature sensor.

Claim 33

Dependent Claim 29 words

The cooling system of claim 26 wherein said controller produces said variable duty cycle control signal with a variable cycle time that is a function of fluctuations in pressure.

Claim 34

Dependent Claim 14 words

The cooling system of claim 26 further comprising pressure sensor coupled to said controller.

Claim 35

Dependent Claim 38 words

The cooling system of claim 26 further comprising refrigerant regulator valve coupled in fluid communication with said evaporator and being electrically controlled by said variable duty cycle control signal to further adjust the capacity of said refrigeration system.

Claim 36

Dependent Claim 29 words

The compressor control system of claim 26 wherein said first state is substantially at one hundred percent capacity and wherein said second state is substantially at zero percent capacity.

Claim 37

Dependent Claim 163 words

A compressor control system, comprising: a compressor that is selectively operable in at least two states, said compressor comprising a pair of fluid compressing members and including a first state corresponding to a first capacity wherein said pair of fluid compressing members are separated by a seal and a second state corresponding to a second capacity lower than said first capacity wherein said seal between said pair of fluid compressing members is broken; a load sensor for sensing a property indicative of demand for cooling; a controller coupled to said load sensor for producing a control signal that cycles based on said sensed property and at a cycle time shorter than the time constant of the load; said controller being coupled to said compressor for causing said compressor to selectively alternate between said first and second states in response to said control signal such that the cumulative effect of said selective alternation adjusts the capacity of said compressor to the demand for cooling.

Claim 38

Dependent Claim 163 words

A compressor control system, comprising: a compressor that is selectively operable in at least two states, said compressor comprising a pair of fluid compressing members and including a first state corresponding to a first capacity wherein said pair of fluid compressing members are separated by a seal and a second state corresponding to a second capacity lower than said first capacity wherein said seal between said pair of fluid compressing members is broken; a load sensor for sensing a property indicative of demand for cooling; a controller coupled to said load sensor for producing a control signal that cycles based on said sensed property and at a cycle time shorter than the time constant of the load; said controller being coupled to said compressor for causing said compressor to selectively alternate between said first and second states in response to said control signal such that the cumulative effect of said selective alternation adjusts the capacity of said compressor to the demand for cooling.

Claim 39

Dependent Claim 30 words

The control system of claim 34 wherein said control signal is a variable duty cycle control signal and wherein said duty cycle is varied in response to said sensed property.

Claim 40

Dependent Claim 36 words

The control system of claim 34 wherein said compressor pumps a refrigerant under pressure and wherein said controller produces said control signal with a variable cycle time that is a function of fluctuations in refrigerant pressure.

Claim 41

Dependent Claim 14 words

The control system of claim 34 wherein said load sensor is a temperature sensor.

Claim 42

Dependent Claim 14 words

The control system of claim 34 further comprising pressure sensor coupled to said controller.

Claim 43

Dependent Claim 23 words

The control system of claim 34 wherein said load sensor is a temperature sensor and further comprising pressure sensor coupled to said controller.

Claim 44

Dependent Claim 54 words

The control system of claim 34 wherein said load sensor senses a property having a first rate of change and wherein said control system further comprising second load sensor that senses a second property having a second rate of change, said second rate of change being substantially greater than said first rate of change.

Claim 45

Dependent Claim 24 words

The control system of claim 40 wherein said load sensor senses changes in temperature and wherein said second load sensor senses changes in pressure.

Claim 46

Dependent Claim 35 words

The control system of claim 34 wherein said compressor includes fluid compressing members and mechanism for selectively rendering said compressing members effective and ineffective to thereby assume said first state and said second state, respectively.

Claim 47

Dependent Claim 32 words

The control system of claim 34 wherein said compressor includes an electric motor and wherein said compressor is configured such that said electric motor remains energized in said first and second states.

Claim 48

Dependent Claim 68 words

The control system of claim 34 wherein said compressor has two mechanical elements separated by a seal, said mechanical elements being movable relative to one another to develop fluid pressure and wherein said compressor includes mechanism to selectively break said seal in response to said control signal to thereby alter said fluid pressure developed while allowing said mechanical elements to maintain substantially constant relative movement with one another.

Claim 49

Dependent Claim 13 words

The control system of claim 34 wherein said compressor is a scroll compressor.

Claim 50

Dependent Claim 21 words

The control system of claim 44 wherein said compressor is a scroll compressor and said two mechanical elements are scroll members.

Claim 51

Dependent Claim 30 words

The control system of claim 34 wherein said controller is coupled to said compressor such that said compressor selectively alternates between said first and second states at said cycle time.

Claim 52

Dependent Claim 31 words

The control system of claim 34 wherein said controller produces a control signal that cycles at a cycle time at least four times shorter than the time constant of the load.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-04-11	2003-10-11	2004-04-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-04-11	2007-10-11	2008-04-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-04-11	2011-10-11	2012-04-11	$7700.00	Window Closed / Lapsed

Adaptive control for a refrigeration system using pulse width modulated duty cycle scroll compressor

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