Control system for briquetters

Claim 2

A control for a briquetting machine or the like, said machine having a pair of relatively movable cooperating rolls forming a roll gap between which material to be compressed is fed and a screw for feeding material to said roll gap, separate power means for causing said relative movement between said rolls and for varying the rate of feed of said screw, a transducer associated with said power means for said rolls for measuring the relative movement therebetween and for producing a signal representative of said measurement, a second transducer associated with said power means for said rolls for measuring a change in the power developed by said power means for said rolls and producing a signal representative of said measurement, and a control means for receiving said signals and for comparing said signals with values representing desired values for said measured values and for controlling the operation of said power means to vary the relative positions of said rolls and the rate of feed of said screw to produce a substantial constant thickness and constant density product.

Claim 3

A control for a briquetting machine or the like, said machine having a pair of relatively movable cooperating rolls forming a roll gap between which material to be compressed is fed and a screw for feeding material to said roll gap, a piston cylinder assembly for causing said relative movement between said rolls, a motor for varying the rate of feed of said screw, a position transducer associated with said piston cylinder assembly and arranged to produce a signal representative of the amount of relative movement between said rolls, a pressure transducer associated with said piston cylinder assembly for measuring any change in pressure thereof and for producing a signal representative thereof, and a control for receiving said signals including means for comparing said signals with values representing a desired position of said rolls and a desired pressure in said piston cylinder assembly, and further including means for producing separate error signals from said comparisons and means for causing said piston cylinder assembly and said motor to operate to change said relatiVe position of said rolls and said rate of feed of said screw, respectively, to reduce said error signals to zero thereby to produce a product having a substantial constant thickness and constant density.

Claim 4

A control for a briquetting machine or the like, said machine having a pair of relatively movable cooperating rolls forming a roll gap between which material to be compressed is fed and a screw for feeding material to said roll gap, a piston cylinder assembly for causing said relative movement between said rolls, a motor for varying the rate of feed of said screw, a position transducer associated with said piston cylinder assembly and arranged to produce a signal representative of the amount of relative movement between said rolls, a pressure transducer associated with said piston cylinder assembly for measuring any change in pressure thereof and for producing a signal representative thereof, and a control for receiving said signals including means for comparing said signals with values representing a desired position of said rolls and a desired pressure in said piston cylinder assembly, and further including means for producing separate error signals from said comparisons and means for causing said piston cylinder assembly and said motor to operate to change said relatiVe position of said rolls and said rate of feed of said screw, respectively, to reduce said error signals to zero thereby to produce a product having a substantial constant thickness and constant density.

Claim 5

A control for a briquetting machine according to claim 2 wherein said control includes a first subcontrol including an amplifier for receiving said position transducer signal and a signal of the desired roll position, said amplifier producing a first corrective signal from said two signals fed to it, a servo-valve associated with said piston cylinder assembly for receiving said first corrective signal for changing the rate of flow to said piston cylinder assembly in order to reduce said first corrective signal to zero, said control further including a second subcontrol, including a second amplifier for receiving said signal from said pressure transducer and a signal representative of the desired pressure in said piston cylinder assembly, said second amplifier producing a second corrective signal from said two signals fed to it, and said motor adapted to receive said second corrective signal and to effect a change in the rate of feed of said screw in order to reduce said second corrective signal to zero.