Interface detection and control using a photodetector array

A fluid separation device comprising:

• a centrifugal separator;
• a pump system;
• and
• a controller configured to control the pump system to convey fluid from a fluid source into a channel defined by a centrifugal separation chamber positioned within the centrifugal separator and to control the centrifugal separator to rotate the centrifugal separation chamber about a rotational axis so as separate at least a portion of the fluid in the channel of the centrifugal separation chamber, wherein
• the centrifugal separator includes an optical monitor assembly comprising
• a light source configured to emit a light,
• a light detector configured as a photodetector array comprising a plurality of individual photodetectors, and
• a collimator positioned between the light source and the light detector,
• the collimator is configured to receive at least a portion of the light emitted by the light source and direct collimated light through the channel of the centrifugal separation chamber in a direction substantially parallel to the rotational axis,
• the light detector is configured to receive at least a portion of the collimated light exiting the channel of the centrifugal separation chamber in said direction substantially parallel to the rotational axis,
• each photodetector of the light detector is configured to emit a signal having a voltage corresponding to an intensity of said at least a portion of the collimated light received by the photodetector, with the signals emitted by the photodetectors collectively defining a composite signal emitted by the light detector,
• the composite signal has a pulse width corresponding to a spatial distribution of the photodetectors of the light detector emitting signals having a voltage greater than a minimum value, with the pulse width of the composite signal being indicative of a location of an interface between separated fluid components within the channel of the centrifugal separation chamber, and
• the controller is configured to receive the composite signal from the light detector and determine the location of the interface between the separated fluid components within the channel of the centrifugal separation chamber based at least in part on the pulse width of the composite signal.

A method for separating a fluid comprising:

• conveying fluid from a fluid source into a channel defined by a centrifugal separation chamber;
• rotating the centrifugal separation chamber about a rotational axis so as separate at least a portion of the fluid in the channel of the centrifugal separation chamber;
• emitting a light through a collimator;
• directing collimated light through the channel of the centrifugal separation chamber in a direction substantially parallel to the rotational axis;
• receiving with a plurality of individual photodetectors at least a portion of the collimated light exiting the channel of the centrifugal separation chamber in said direction substantially parallel to the rotational axis;
• emitting signals from the photodetectors as a composite signal having a pulse width corresponding to a spatial distribution of the photodetectors emitting signals having a voltage greater than a minimum value, with the voltage of each signal corresponding to an intensity of said at least a portion of the collimated light received by the photodetector and with the pulse width of the composite signal being indicative of a location of an interface between separated fluid components within the channel of the centrifugal separation chamber;
• and
• determining the location of the interface between the separated fluid components within the channel of the centrifugal separation chamber based at least in part on the pulse width of the composite signal.