Refrigeration unit control with shutdown evaluation and automatic restart
First Claim
1. A method of operating a refrigeration unit, comprising the steps of:
- monitoring a predetermined parameter of the refrigeration unit, a predetermined value of which indicates a mandatory shut down condition,shutting the refrigeration unit down in the event the monitored parameter reaches the mandatory shut down condition,incrementing a shut down count when the refrigeration unit is shut down due to the mandatory shut down condition,detecting when the predetermined monitored parameter has a value which permits re-starting of the refrigeration unit,determining the value of the shut down count,restarting the refrigeration unit in response to the detecting step finding that restarting is permitted and the value of the shut down count is less than a predetermined value,modifying the operation of the refrigeration unit when restarted, with the modification being selected to reduce the probability of the monitored parameter reaching the predetermined shut down condition,timing the operation of the refrigeration unit when started by the restarting step,and resetting the shut down count when the refrigeration unit operates for a predetermined period of time without a mandatory shut down.
2 Assignments
0 Petitions
Accused Products
Abstract
Methods and apparatus for monitoring conditions which may cause shut down of a refrigeration unit. When a condition of the refrigeration unit is detected which requires shut down, a shut down counter is incremented and the shut down is made with the provision for automatic restart of the refrigeration unit in response to predetermined parameters of the refrigeration unit. When the predetermined parameters initiate automatic re-start of the refrigeration unit, a timer is started. If the refrigeration unit operates for a predetermined period of time without shut down, the counting means is reset. A shut down before expiration of the predetermined timing period again increments the shut down counter. In one embodiment, when a predetermined condition which may cause shut down approaches a predetermined shut down value, the methods and apparatus modify the operation of the refrigeration unit one or more times in an attempt to prevent shut down. A predetermined count value on the shut down counter prevents further automatic re-starts of the refrigeration unit. In a preferred embodiment, the monitored conditions which may cause shut down are the high side pressure of the refrigeration unit, and, when a refrigerant compressor is driven by an internal combustion engine, the temperature of the engine.
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Citations
36 Claims
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1. A method of operating a refrigeration unit, comprising the steps of:
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monitoring a predetermined parameter of the refrigeration unit, a predetermined value of which indicates a mandatory shut down condition, shutting the refrigeration unit down in the event the monitored parameter reaches the mandatory shut down condition, incrementing a shut down count when the refrigeration unit is shut down due to the mandatory shut down condition, detecting when the predetermined monitored parameter has a value which permits re-starting of the refrigeration unit, determining the value of the shut down count, restarting the refrigeration unit in response to the detecting step finding that restarting is permitted and the value of the shut down count is less than a predetermined value, modifying the operation of the refrigeration unit when restarted, with the modification being selected to reduce the probability of the monitored parameter reaching the predetermined shut down condition, timing the operation of the refrigeration unit when started by the restarting step, and resetting the shut down count when the refrigeration unit operates for a predetermined period of time without a mandatory shut down. - View Dependent Claims (2, 3)
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4. A method of operating a refrigeration unit having high and low pressure sides, a refrigerant compressor connected between the high and low pressure sides, and pressure sensor means which monitors the high pressure side, comprising the steps of:
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monitoring the high pressure side of the refrigeration unit, shutting the refrigeration unit down when the monitoring step detects a first predetermined pressure which indicates an over-pressure condition, incrementing a shut down count when the refrigeration unit is shut down in response to the over-pressure condition, continuing the step of monitoring the high pressure side of the refrigeration unit during shut down, determining the value of the shut down count, restarting the refrigeration unit as a function of pressure of the high pressure side and the shut down count value, restarting the refrigeration unit only after the pressure monitoring step finds the pressure of the high pressure side has dropped below the first predetermined value to a second predetermined value, and then only when the determining step finds the value of the shut down count is less than a predetermined value, modifying the operation of the refrigeration unit to reduce the load on the compressor when the refrigeration unit is started by the restarting step, timing the operation of the refrigeration unit when started by the restarting step, and resetting the shut down count when the refrigeration unit operates for a predetermined period of time without being shut down again by the step of shutting the refrigeration unit in response to an over-pressure condition. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of operating a refrigeration unit having a refrigerant compressor driven by an internal combustion engine having a temperature sensor, comprising the steps of:
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monitoring the temperature of the internal combustion engine, initiating a first predetermined modification of the refrigeration unit which reduces the load on the internal combustion engine when the monitoring step detects a first predetermined over-temperature condition, shutting the internal combustion engine down when the monitoring step detects a predetermined maximum over-temperature condition, incrementing a shut down count when the internal combustion engine is shut down in response to the maximum over-temperature condition, determining the value of the shut down count, restarting the internal combustion engine as a function of the temperature of the internal combustion engine and the value of the shut down count, restarting the internal combustion engine only when the monitoring step detects the temperature of the internal combustion engine has dropped to a predetermined value, and then only when the determining step finds the shut down count value is below a predetermined count value, timing the operating time of the internal combustion engine when started by the restarting step, and resetting the shut down count when the internal combustion engine operates for a predetermined period of time without being shut down again in response to the predetermined maximum over-temperature condition. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A refrigeration unit, comprising:
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monitor means for monitoring a predetermined parameter of the refrigeration unit, a predetermined value of which indicates a mandatory shut down condition, means for shutting the refrigeration unit down in the event the monitor means indicates that the monitored parameter has reached the mandatory shut down condition, shut down counting means, means for incrementing the shut down counting means in response to the refrigeration unit being shut down by the mandatory shut down condition, said monitor means detecting when the predetermined monitored parameter has a value which permits restarting of the refrigeration unit, means for restarting the refrigeration unit in response to the monitor means finding that restarting of the refrigeration unit is permitted and the value of the shut down counting means is less than a predetermined value, means for modifying the operation of the refrigeration unit when restarted, with the modification being selected to reduce the probability of the monitored parameter from reaching the predetermined shut down condition, timing means for timing the operation of the refrigeration unit when started by the restarting step, and means for resetting the shut down counting means when the refrigeration unit operates for a predetermined period of time without a mandatory shut down. - View Dependent Claims (20, 21)
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22. A refrigeration unit having high and low pressure sides, a refrigerant compressor connected between the high and low pressure sides, and pressure sensor means disposed to sense the pressure of the high pressure side, with the pressure sensor means initiating shut down of the refrigeration unit down in response to detection of a predetermined over-pressure condition, comprising:
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shut down counting means, means incrementing the shut down counting means when the refrigeration unit is shut down in response to the predetermined over pressure condition, means restarting the refrigeration unit in response to the pressure sensor means and the shut down counting means, restarting the refrigeration unit only when the pressure sensor means finds the pressure of the high side has dropped below the first predetermined value to a second predetermined value, and then only when the value of the shut down counting means is less than a predetermined value, means modifying the operation of the refrigeration unit to reduce the load on the compressor when the refrigeration unit is started by the restarting means, timing means timing the operation of the refrigeration unit when started by the restarting means, and means resetting the shut down count when the refrigeration unit operates for a predetermined period of time without being shut down again in response to an over-pressure condition. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A refrigeration unit having a refrigerant compressor driven by an internal combustion engine, and temperature sensor means for sensing the temperature of the internal combustion engine, comprising:
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means initiating a first predetermined modification of the refrigeration unit which reduces the load on the internal combustion engine when the temperature sensor means detects a first predetermined over-temperature condition, shut down means for shutting the internal combustion engine down when the temperature sensor means detects a predetermined maximum over-temperature condition, shut down counting means, means incrementing said shut down counting means when the internal combustion engine is shut down in response to the maximum over-temperature condition, means for restarting the internal combustion engine as a function of the temperature of the internal combustion engine and the value of the shut down counting means, with said restart means restarting the internal combustion engine only when the temperature of the internal combustion engine has dropped to a predetermined value, and the value of the shut down counting means is below a predetermined count value, timing means for timing the operating time of the internal combustion engine when started by the restarting means, and means resetting the shut down counting means when the internal combustion engine has operated for a predetermined period of time without being shut down again by the shut down means. - View Dependent Claims (32, 33, 34, 35, 36)
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Specification