Refiner Control via No-Load Power Tracking

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Solution Overview

Problem

Refiners used for treating fibrous materials face inefficiencies due to constant no-load power being misjudged, leading to excessive energy consumption and potential tool damage from wear, as existing methods fail to accurately account for changing no-load power over the service life of treatment tools.

Innovation Solution

Measuring and storing no-load power values multiple times during gap opening and closing, forming average values to accurately reflect current conditions, and updating these values regularly to adjust total power consumption, thereby preventing excessive energy use and tool damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the no-load power is determined once before commissioning and used as a basis for machine control, then the control system is simple, but the no-load power becomes inaccurate over time due to tool wear

Engineering Contradiction:
Improvecontrol system complexityVSAvoidno-load power measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control system performs preliminary measurements of no-load power at multiple points during the service life of treatment tools (before commissioning, after 1000 hours, after 2000 hours, etc.) and stores these values in advance. This allows the system to have accurate no-load power data ready before it is needed for control decisions, eliminating the need for complex real-time measurement while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter being measured from a single static no-load power value to multiple time-point measurements. By measuring no-load power at different service life stages of the treatment tools and selecting or averaging appropriate values, the system adapts to parameter changes caused by tool wear while keeping the control logic relatively simple.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the treatment gap is closed to increase treatment intensity, then the fiber treatment efficiency improves, but the power consumption increases excessively and may cause tool damage

Engineering Contradiction:
Improvefiber treatment efficiencyVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control system continuously monitors the actual power consumption during refiner operation and compares it with the no-load power value. When the difference exceeds a predetermined threshold (indicating excessive power consumption), the system provides feedback to adjust the treatment gap or reduce power input, preventing tool damage while maintaining optimal treatment efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the treatment gap width based on real-time power consumption measurements. Instead of maintaining a fixed gap, the gap is automatically modified in response to changing power demands, allowing the system to optimize between treatment intensity and power consumption throughout the tool service life.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If the treatment gap is opened wide to reduce power consumption, then energy efficiency improves, but the treatment efficiency decreases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidtreatment efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The system changes the operating parameters (treatment gap width, rotation speed, power input) based on the selected no-load power value corresponding to the current tool service life stage. This allows optimal parameter combinations that balance energy efficiency and treatment efficiency at different points in tool wear progression.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3452657B1Method for controlling a refiner for treating fibrous material
Publication Date: 2019.12.25 VOITH PATENT GMBH
  • EP3452657B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for controlling a device for treating fibrous material (1) at least partially on the basis of the idle power (PL) thereof, wherein the device has a housing (2), in which a first treatment tool (3) and a second treatment tool (4) are arranged, the treatment tools (3, 4) are fastened in each case on a base plate (7, 8), have a rotationally symmetrical shape, are arranged coaxially with respect to one another, rotate relative to one another about a common axis (5), and delimit a treatment nip (6), through which the fibrous material (1) flows radially and the nip width of which can be changed via an axial displacement of at least one base plate (7, 8) of a treatment tool (3, 4). Here, the controller of the device is to be improved by a value of the idle power (PL) in the presence of fibrous material (1) or water being measured over the service life of at least one treatment tool (3, 4), being stored in a memory of the controller, and being evaluated by the controller on its own or in conjunction with other values.