Apparatus and method for monitoring and regulating cryogenic cooling

Abstract

An apparatus and method for monitoring and/or controlling cryogenic cooling by measuring the opacity of the vapor cloud ( 113 ) generated from a cryogenic cooling device ( 112 ). The opacity is determined by measuring the reduction in intensity of a light beam ( 127 ) passed through the vapor cloud ( 113 ). The opacity measurements are used to control an operating parameter of the system, such as the cooling rate of the cryogenic cooling device ( 112 ). The opacity measurements may be normalized to compensate for variables, other than temperature of the workpiece ( 119 ) and cooling rate, which may affect the opacity of the vapor cloud ( 113 ).

1 . An apparatus for use with a system having a cryogenic cooling component that generates a vapor cloud when operating, the apparatus comprising:
 a first emitter that is adapted to emit a first light beam at a first initial intensity;   a first receiver having a first sensor that is adapted to detect a first sensed intensity, the first sensed intensity being the intensity of the first light beam at the first sensor when the first light beam is directed at the first sensor, the first receiver being adapted to generate a first sensor signal that is a function of the first sensed intensity, the first emitter and first sensor having a first operating position in which the first emitter and first sensor are positioned and oriented so that the first light beam is directed onto the first sensor and the first light beam passes through the vapor cloud at least once before being received by the first sensor; and   a controller that is programmed to set and/or adjust at least one operating parameter of the system based on controller data, the controller data comprising the first sensor signal.   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one operating parameter comprises a cooling rate of the cryogenic cooling component. 
     
     
         3 . The apparatus of  claim 1 , wherein the at least one operating parameter comprises an alarm that is activated if the first sensor signal indicates that opacity of the vapor cloud is outside of a predetermined range. 
     
     
         4 . The apparatus of  claim 1 , wherein the first light beam comprises a visible laser. 
     
     
         5 . The apparatus of  claim 1 , further comprising a sensor group comprising at least one parameter sensor, each of the at least one parameter sensor being adapted to measure a parameter, other than the temperature of a substrate on which the cooling component is being applied, that may affect the opacity of the vapor cloud and to generate a parameter sensor signal that is a function of the parameter being sensed by the at least one parameter sensor, wherein the data further comprises the parameter sensor signal from each of the at least one sensor. 
     
     
         6 . The apparatus of  claim 1 , further comprising a third sensor adapted to measure relative humidity of ambient air in the vicinity of the vapor cloud and adapted to generate a third signal that is a function of the measured relative humidity and wherein the controller data further comprises the third signal. 
     
     
         7 . The apparatus of  claim 1 , further comprising a fourth sensor adapted to determine the velocity of a substrate as it moves past the cryogenic cooling component and adapted to generate a fourth signal that is a function of the measured velocity and wherein the controller data further comprises the fourth signal. 
     
     
         8 . The apparatus of  claim 1 , first emitter and first receiver are positioned so that the light beam is reflected by a first surface before being received by the first sensor. 
     
     
         9 . The apparatus of  claim 8 , wherein the first sensor is positioned adjacent to the first emitter. 
     
     
         10 . The apparatus of  claim 8 , further comprising:
 a second emitter that is adapted to emit a second light beam at a second initial intensity;   a second receiver having a second sensor that is adapted to detect a second sensed intensity, the second sensed intensity being the intensity of the second light beam at the second sensor when the second light beam is directed at the second sensor, the second receiver being adapted to generate a second sensor signal that is a function of the second sensed intensity, the second emitter and second sensor having a second operating position in which the second emitter and second sensor are positioned so that the second light beam is directed onto the second sensor, the second light beam is reflected by either the first surface or a second surface before being received by the second sensor, and the second light beam does not pass through the vapor cloud at least once before being received by the second sensor; and   wherein the controller is programmed to set and/or adjust the at least one operating parameter of the system based on the controller data and when the first emitter and second sensor are in the first operating position and the second emitter and second sensor are in the second operating position, the controller data comprising the first sensor signal and the second sensor signal.   
     
     
         11 . The apparatus of  claim 10 , wherein the first sensor is positioned adjacent to the first emitter and the second sensor is positioned adjacent to the second emitter. 
     
     
         12 . An apparatus for use with a system having a cryogenic cooling component that generates a vapor cloud when operated, the apparatus comprising:
 means for measuring the relative opacity of at least a portion of the vapor cloud; and   a controller in communication with the means for measuring, the controller being adapted to set and/or adjust at least one operating parameter of the system based on the relative opacity of the at least a portion of the vapor cloud.   
     
     
         13 . The apparatus of  claim 12 , wherein the at least one operating parameter comprises a cooling rate of the cryogenic cooling component. 
     
     
         14 . The apparatus of  claim 12 , wherein the at least one operating parameter comprises an alarm that is activated if the first sensor signal indicates that opacity of the at least a portion of the vapor cloud is outside of a predetermined range. 
     
     
         15 . A method used with a system having a cryogenic cooling component, the method comprising:
 determining the relative opacity of at least a portion of a cryogenic vapor cloud; and   setting and/or adjusting at least one operating parameter of the system based on the relative opacity of the at least a portion of the cryogenic vapor cloud.   
     
     
         16 . The method of  claim 15 , wherein determining the relative opacity of the at least a portion of the cryogenic vapor cloud further comprises:
 directing a first light beam through at least a portion of a cryogenic vapor cloud, the first light beam having a first initial intensity; and   measuring the intensity of the first light beam after it has passed through the at least a portion of a cryogenic vapor cloud, the measured intensity comprising a first sensed intensity.   
     
     
         17 . The method of  claim 16 , wherein determining the relative opacity of at least a portion of the cryogenic vapor cloud further comprises:
 reflecting the first light beam on a first surface before measuring the intensity of the first light beam.   
     
     
         18 . The method of  claim 17 , wherein determining the relative opacity of at least a portion of the cryogenic vapor cloud further comprises:
 measuring the intensity of a second light beam after it has been reflected on one of the first surface or a second surface without passing through any portion of a cryogenic vapor cloud, the measured intensity comprising a second sensed intensity; and   comparing the first sensed intensity to the second sensed intensity.   
     
     
         19 . The method of  claim 16 , wherein determining the relative opacity of at least a portion of the cryogenic vapor cloud further comprises:
 reflecting the first light beam on a first surface before measuring the intensity of the first light beam.   
     
     
         20 . The method of  claim 15 , wherein the setting and/or adjusting step further comprises:
 setting and/or adjusting a cooling rate of the cryogenic cooling component based on the relative opacity of the at least a portion of the cryogenic vapor cloud.   
     
     
         21 . The method of  claim 16 , wherein:
 setting and/or adjusting the cooling rate of the cryogenic cooling component comprises setting and/or adjusting a non-linear cooling profile of the cryogenic cooling component based on the relative opacity of at least a portion of the cryogenic vapor cloud; and   determining the relative opacity of at least a portion of the cryogenic vapor cloud comprises measuring the relative opacity of a cryogenic vapor cloud at a plurality of locations.