Method for operating a pulper for producing a suspension, in particular a fibrous suspension

Abstract

A method for operating a screening device for cleaning a fibrous suspension includes the steps of: providing that the screening device includes a housing, a rotor arranged in the housing, and a screen; feeding the fibrous suspension and a rinsing water to the screening device; passing a portion of the fibrous suspension through the screen; discharging the portion of the fibrous suspension passing through the screen via an accepted stock discharge; and regulating, depending on a power consumption of a rotor drive, at least one of an inflow into the screening device and a cycle duration.

What is claimed is: 
     
         1 . A method for operating a screening device for cleaning a fibrous suspension, the method comprising the steps of:
 providing that the screening device includes a housing, a rotor arranged in the housing, and a screen;   feeding the fibrous suspension and a rinsing water to the screening device;   passing a portion of the fibrous suspension through the screen;   discharging the portion of the fibrous suspension passing through the screen via an accepted stock discharge; and   regulating, depending on a power consumption of a rotor drive, at least one of an inflow into the screening device and a cycle duration.   
     
     
         2 . The method for operating the screening device according to  claim 1 , wherein the cycle duration of at least one subsequent cycle is regulated depending on the power consumption of the rotor drive. 
     
     
         3 . The method for operating a screening device according to  claim 2 , wherein the at least one subsequent cycle is at least one of a throughput cycle, a post-dissolving cycle, a rinse cycle, and a discharge cycle. 
     
     
         4 . The method for operating the screening device according to  claim 1 , wherein, if the power consumption of the rotor drive exceeds a predetermined limit value—at least at a start of a subsequent rinse cycle—an inflow of the rinsing water is reduced compared to a maximum possible inflow of the rinsing water. 
     
     
         5 . The method for operating the screening device according to  claim 1 , wherein a cycle duration of at least one of a throughput cycle and a rinse cycle is regulated depending on a flow of an accepted stock. 
     
     
         6 . The method for operating the screening device according to  claim 1 , wherein at least one of an inlet pressure and a differential pressure is considered for a pressure of the accepted stock discharge when regulating a subsequent cycle duration. 
     
     
         7 . The method for operating the screening device according to  claim 1 , wherein a plurality of system-specific limit values are read in or are manually entered or are stored during a start-up. 
     
     
         8 . The method for operating the screening device according to  claim 7 , wherein a maximum system-specific accepted stock flow will be stored or is stored. 
     
     
         9 . The method for operating the screening device according to  claim 8 , wherein at least one of a factory default and a basic setting is stored in a control unit, and wherein an operation without adaptive control is possible with the factory default and the basic setting. 
     
     
         10 . The method for operating the screening device according to  claim 8 , wherein, if the power consumption of the rotor drive is outside a stored power range, an operation is continued based on data from a basic setting or a factory default until a recorded operating data is again within a stored standard range. 
     
     
         11 . The method for operating the screening device according to  claim 8 , wherein, if the power consumption of the rotor drive is outside a stored power range in a throughput cycle, an operation is continued based on data from a basic setting or a factory default until a recorded operating data is again within a stored standard range. 
     
     
         12 . The method for operating the screening device according to  claim 8 , wherein, if an operating parameter is outside a stored standard range, the method is continued by reverting to a predetermined number of cycles, and a plurality of the operating parameter used for the predetermined number of cycles are adaptively adjusted. 
     
     
         13 . A method for operating a system, the method comprising the steps of:
 providing that the system includes a first screening device, a second screening device, and a pulper, the first screening device configured for being cyclically operated and thus for being operated in a plurality of cycles, the second screening device configured for being cyclically operated and thus for being operated in a plurality of cycles, the second screening device being arranged in parallel to the first screening device; and   coordinating the plurality of cycles of the first screening device and the plurality of cycles of the second screening device with each other for utilizing at least one peripheral equipment of a line of the system, in that at least one of (a) at least one of a plurality of rinse cycles is at least one of (i) extended and (ii) shortened from a plurality of currently ongoing sequences and (b) at least a throughput cycle is shortened.   
     
     
         14 . A method for operating a system, the method comprising the steps of:
 providing that the system includes a pulper and a screening device, the method including a first method for operating the screening device for cleaning a fibrous suspension, the first method including the steps of:
 providing that the screening device includes a housing, a rotor arranged in the housing, and a screen; 
 feeding the fibrous suspension and a rinsing water to the screening device; 
 passing a portion of the fibrous suspension through the screen; 
 discharging the portion of the fibrous suspension passing through the screen via an accepted stock discharge; and 
 regulating, depending on a power consumption of a rotor drive, at least one of an inflow into the screening device and a cycle duration; and 
   returning the fibrous suspension to the pulper.   
     
     
         15 . The method for operating the system according to  claim 14 , wherein a consistency and a volume of the fibrous suspension returned to the pulper is considered for provision of a stock density consistency within a predetermined stock density range of an accepted pulp stock. 
     
     
         16 . The method for operating the system according to  claim 14 , wherein a consistency and a volume of the fibrous suspension returned to the pulper is considered for preparation of a stock density consistency in the pulper. 
     
     
         17 . A system including a pulper, the system comprising:
 at least one screening device; and   a control unit, which is configured for carrying out a method for operating the at least one screening device for cleaning a fibrous suspension, the method including the steps of:
 providing that the at least one screening device includes a housing, a rotor arranged in the housing, and a screen; 
 feeding the fibrous suspension and a rinsing water to the at least one screening device; 
 passing a portion of the fibrous suspension through the screen; 
 discharging the portion of the fibrous suspension passing through the screen via an accepted stock discharge; and 
 regulating, depending on a power consumption of a rotor drive, at least one of an inflow into the at least one screening device and a cycle duration; 
   an infeed for a rinsing water to the at least one screening device; and   a control valve, which is arranged in the infeed for the rinsing water to the at least one screening device.   
     
     
         18 . The system according to  claim 17 , wherein the control valve is configured for being actuated depending at least on the power consumption-which is detected—of the rotor drive.