Adjusting Blade Gap in Processing Equipment for Processing Fibrous Material

Abstract

A loading device ( 10 ) is used to adjust the size of a blade gap ( 9 ) in processing equipment for processing fibrous material. The loading device has a gearing ( 12 ) coupled in connection with a processing element ( 5, 6 ) to move the processing element ( 5, 6 ) in respect of another processing element ( 5, 6 ) for adjusting the size of the blade gap ( 9 ) between the processing elements. A cage induction motor ( 14 ) has a shaft ( 15 ) coupled to the gearing for operating the gearing, a position sensor ( 16 ) for measuring a rotational position (M-RP) of the shaft of the motor for indicating a position of the processing element in respect of the another processing element, and a frequency converter ( 17 ) coupled to the position sensor and to the motor for controlling the operation of the motor based on the measured rotational position of the shaft of the motor.

1 - 15 . (canceled) 
     
     
         16 . A loading device for adjusting a size of a blade gap in processing equipment for processing fibrous material, the loading device comprising:
 a gearing to be coupled in connection with at least one processing element of the processing equipment to move the at least one processing element in respect of at least one another processing element of the processing equipment for adjusting the size of the blade gap between the processing elements;   a cage induction motor comprising a shaft coupled to the gearing for operating the gearing to move the at least one processing element with respect to the at least one another processing element;   a position sensor for measuring a rotational position of the shaft of the cage induction motor for indicating a position of the at least one processing element in respect of the at least one another processing element; and   a frequency converter coupled to the position sensor and to the cage induction motor for controlling the operation of the cage induction motor based at least on the measured rotational position of the shaft of the cage induction motor.   
     
     
         17 . The loading device of  claim 16 , wherein the position sensor is arranged at the shaft of the cage induction motor. 
     
     
         18 . The loading device of  claim 16  wherein the frequency converter comprises a position control module configured to determine a position control signal for controlling the operation of the cage induction motor based at least on the measured rotational position of the shaft of the cage induction motor. 
     
     
         19 . The loading device of  claim 18 , wherein the position control module is configured to determine the position control signal based at least on the measured rotational position of the shaft of the cage induction motor and a set value set for the size of the blade gap. 
     
     
         20 . The loading device of  claim 16  wherein the frequency converter comprises a torque control module configured to determine a torque of the cage induction motor applied to move the at least one processing element in respect of the at least one another processing element and to compare the determined torque with a maximum torque limit value and to cause the cage induction motor to stop in the event of the determined torque being equal to or exceeding the maximum torque limit value. 
     
     
         21 . The loading device of  claim 16  wherein the loading device comprises a blade gap control module configured to determine setting parameters for an operation of the frequency converter. 
     
     
         22 . The loading device of  claim 21  wherein the blade gap control module is configured to determine at least one of the following parameters: the set value for the size of the blade gap and the maximum torque limit value. 
     
     
         23 . The loading device of  claim 16  wherein the loading device is configured to be used to adjust the size of the blade gap in a refiner for refining fibrous material or in a disperser for dispersing fibrous material. 
     
     
         24 . The loading device of  claim 16  further comprising:
 processing equipment for processing fibrous material and comprising at least two substantially oppositely positioned processing elements at least one of which is movable in an axial direction of the processing equipment for adjusting the size of the blade gap between the processing elements; and 
 wherein the loading device is coupled to the processing equipment for moving at least one processing element in respect of at least one another processing element in the axial direction of the processing equipment for adjusting the size of the blade gap between the processing elements. 
 
     
     
         25 . The arrangement of  claim 24 , wherein the processing equipment is a refiner for refining fibrous material or a disperser for dispersing fibrous material. 
     
     
         26 . A method for adjusting a size of a blade gap in processing equipment for processing fibrous material, in which method at least one processing element of the processing equipment is moved in respect of at least one another processing element of the processing equipment by at least one loading device for adjusting the size of the blade gap between the processing elements, the loading device comprising:
 a gearing coupled in connection with at least one processing element of the processing equipment to move the at least one processing element in respect of at least one another processing element of the processing equipment for adjusting the size of the blade gap between the processing elements;   a cage induction motor comprising a shaft coupled to the gearing for operating the gearing to move the at least one processing element with respect to the at least one another processing element;   a position sensor for measuring a rotational position of the shaft of the cage induction motor for indicating a position of the at least one processing element in respect of the at least one another processing element; and   a frequency converter coupled to the position sensor and to the cage induction motor for controlling the operation of the cage induction motor based at least on the measured rotational position of the shaft of the cage induction motor; the method comprising the steps of:   measuring a rotational position of the shaft of the cage induction motor for indicating a position of the at least one processing element in respect of the at least one another processing element;   determining a position control signal for controlling the operation of the cage induction motor based at least on the measured rotational position of the shaft of the cage induction motor; and   controlling the operation of the cage induction motor by the frequency converter according to the determined position control signal to control the position of the at least one processing element in respect of the at least one another processing element for adjusting the size of the blade gap between the processing elements.   
     
     
         27 . The method of  claim 26 , further comprising the steps of:
 determining a set value for the size of the blade gap; and   determining the position control signal based at least on the measured rotational position of the shaft of the cage induction motor and the set value determined for the size of the blade gap.   
     
     
         28 . The method of  claim 26 , further comprising operating by the cage induction motor the gearing coupled to the at least one processing element for moving the at least one processing element in respect of the at least one another processing element. 
     
     
         29 . The method of  claim 26 , further comprising:
 determining a torque of the cage induction motor when the at least one processing element is moved in respect of the at least one another processing element;   comparing the determined torque with the maximum torque limit value; and   interrupting the movement of the at least one processing element in respect of the at least one another processing element in response to the determined torque being equal to or exceeding the maximum torque limit value.   
     
     
         30 . The method of  claim 26 , further wherein the processing equipment is a refiner for refining fibrous material or a disperser for dispersing fibrous material.