1. A control system for a water scalping tank or like apparatus for classifying and reblending granular material in accordance with a quantitative ratio specification, of the kind including a master classification station and a series of secondary classification stations at which different classes of mateRial accumulate at varying rates, each station including a sensor for developing a discharge signal indicative of the presence of sufficient accumulated material to allow discharge at a relatively constant rate for a minimum time interval, each station further including discharge means actuatable between a closed condition in which no material is discharged from the station, a normal discharge condition in which material is discharged to a specification reblending receptacle, and an auxiliary discharge condition in which material is discharged to an auxiliary receptacle, the control system comprising: a plurality of actuating means, one for each classification station, for actuating the discharge means for that station from its closed condition to a discharge condition in response to a discharge signal from the sensor for that station, and further for actuating the discharge means to its auxiliary discharge condition in response to a diversion signal; a plurality of timing means, one for each classification station, for generating a timing signal representative of the time that classification station is in its normal discharge condition; a series of comparator means, each including a settable ratio control, one comparator for each secondary classification station, for continuously comparing the master station timing signal in pre-set ratio with the secondary station timing signal to develop an excess signal whenever there is an excessive discharge from that secondary station to the specification receptacle and to develop a deficiency signal whenever there is an inadequate discharge from that secondary station to the specification receptacle, the excess signal from each secondary station being applied to the actuating means for that station as a diversion signal; and means, coupled to all of the comparator means, for applying a diversion signal to the actuating means of the master station upon occurrence of a deficiency signal from any of the comparators.

8. A control system for a water scalping Tank or like apparatus for classifying and reblending granular material into two specification products in accordance with two quantitative ratio specifications of the kind including a master classification station and a series of secondary classification stations at which different classes of material accumulate at varying rates, each station including a sensor for developing a discharge signal indicative of the presence of suffficient accumulated material to allow discharge at a relatively constant rate for a minimum time interval, each station further including discharge means actuatable between a closed condition in which no material is discharged from the station, a first discharge condition in which material is discharged to a first specification reblending receptacle, a second discharge condition in which material is discharged to a second specification reblending receptacle, and an auxiliary discharge condition in which material is discharged to auxiliary receptacle, the control system comprising: a plurality of actuating means, one for each classification station, for actuating the discharge means for that station from its closed condition to a discharge condition in response to a discharge signal from the sensor for that station, and further for actuating the discharge means for that station between its first and second discharge conditions and its auxiliary discharge condition in response to diversion signals; a first timing means and a second timing means for each classification station, generating a first timing signal representative of the time that classification station is in its first discharge condition and the second timing means generating a second timing signal representative of the time that classification station is in its second discharge condition; a series of comparator means, each including a settable ratio control, comprising a first comparator and a second comparator for each secondary classification station, the first comparator continuously comparing the master station first timing signal in pre-set ratio with the secondary station first timing signal to develop a first excess signal whenever there is an excessive discharge from that secondary station to the first specification receptacle and to develop a first deficiency signal whenever there is an inadequate discharge from that secondary station to the first specification receptacle, the first excess signal from each secondary station being applied to the actuating means for that station as a first diversion signal to inhibit operation in the first discharge condition, the second comparator for each secondary classification station continuously comparing the master station second timing signal in pre-set ratio with the secondary station second timing signal to develop a second excess signal whenever there is an excessive discharge from that secondary station to the second specification receptacle and to develop a second deficiency signal whenever there is an inadequate discharge from that secondary station to the second specification receptacle, the second excess signal from each secondary station being applied to the actuating means for that station as a second diversion signal to inhibit operation in the second discharge condition; first master diversion means, coupled to all of the first comparator means, for applying a first diversion signal to the actuating means of the master station upon occurrence of a first deficiency signal for any of the secondary stations to inhibit operation in the first discharge condition; and second master diversion means, coupled to all of the second comparator means, for applying a second diversion signal to the actuating means of the master station upon occurrence of a second deficiency signal for any of the secondary stations.