Forces on bars in high-consistency mill-scale refiners: Effect of consistency

Olender, D.; Wild, Peter; Byrnes, Peter; Ouellet, D.R.; Sabourin, Marc

doi:10.3183/npprj-2008-23-02-p218-223

Cited by 11 publications

(12 citation statements)

References 1 publication

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“…Other features observed in the signals have been explained in part by plate geometry and probe width [5]. In general, the acquired force signals are believed to be accurate and representative of those experienced in the reject refiner.…”

Section: Resultsmentioning

confidence: 77%

“…An array of fourth generation sensors were installed in a 114 cm (45 in) diameter refiner at a Catalyst Paper Corporation Mill, in Port Alberni, BC, CA in 2005. A detailed account of the installation and the operating conditions are described elsewhere [5]. The installation was significant in both the scale of the machine and the duration of the tests, which lasted for the entire life of the plates (1800 h, or 3 months).…”

Section: Recent Mill Trialmentioning

confidence: 99%

“…This prototype sensor was tested in an atmospheric laboratory-scale refiner. Three subsequent generations of the force sensor described by Siadat et al [1] have since been designed, built, and tested in increasingly large refiners, including both laboratory and pilot-scale refiners [2][3][4] and, most recently, a successful extended trial at a Catalyst Paper Corporation mill in Port Alberni, BC [5]. Development of the sensor design has required improvements in both durability and dynamic behaviour.…”

Section: Introductionmentioning

confidence: 99%

“…For example, these sensors have been used to observe the effect of rotor tram on bar forces [18], to make an estimate of the mean residence time of the pulp in the refining zone [4], and also to give advanced warning of plate clashes [19]. By recording many thousands of barcrossings and studying their distributions, the general character of these impacts has also been revealed, including how their regularity and magnitude can vary due to machine scale and stage of refinement [5,20].…”

Section: Introductionmentioning

confidence: 99%

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A piezoelectric force sensor for mill-scale chip refiners

Olender

Wild

Byrnes

2008

Proceedings of the Institution of Mechanical Engineers, Part E:

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Refiners are used in the pulp and paper industry to separate wood chips into individual fibres and to develop the morphology of fibres to be suitable for the type and grade of paper to be produced. Within a refiner are discs, at least one of which rotates at high speed and all of which are lined with radial patterns of bars on their opposed surfaces. A mixture of chips and water is accelerated radially through the space between the discs. Compressive and shear forces are applied to chips and fibres as the bars on the opposed discs cross each other. Experiments have shown that certain process variables can greatly affect the forces applied to chips or fibres when bars cross. These findings suggest that the contact mechanics of bar-crossings are a significant factor in the development of fibre properties. To investigate these contact mechanics in operating refiners, a piezoelectric-based sensor has been developed to measure the forces applied to the chips and fibres by the bars. The sensor replaces a small section of a refiner bar and is sensitive to both axial and tangential forces. The current paper describes the evolution of the design of this sensor from a proof-of-concept prototype for a laboratory-scale refiner to the latest generation sensor for a mill-scale refiner. Performance during the most recent mill trials is presented.

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Section: Resultsmentioning

confidence: 77%

Section: Recent Mill Trialmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A piezoelectric force sensor for mill-scale chip refiners

Olender

Wild

Byrnes

2008

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…Backlund et al, 2 Senger et al, 3 and Olender 4 designed sensors in which the active sensor part was isolated from the plate gap. The drawback with these sensors is that their design becomes quite complicated and that they measure forces only in a small region so that in order to get a reasonably accurate description of the radial distribution of forces, a large number of sensors are required.…”

Section: Introductionmentioning

confidence: 99%

Measuring Tangential Forces in a Pulp Refiner: A Novel Approach

2014

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To get some insight into the processes that are active during the refining of wood, the tangential force distribution in the plate gap is of interest. Over the years several designs of force sensors have been developed for this purpose. One drawback with these designs is that each sensor measures forces over quite a small area such that in order to cover the whole disc with a reasonably good resolution, many sensors have to be used. Also, there are problems to protect the active parts of the sensors from the harsh environment in the plate gap. In this paper a different concept is presented, in that the sensor is continuous and consists of a hollow radial bar equipped with strain gages on the inside. The force sensor was calibrated before mounting by loading it with a known load in the tangential direction and in different positions while measuring the strains in the points where the gages are located. This makes it possible to determine the so-called influence (or Green) functions. Knowing these it is possible to determine the tangential force distribution from strain values measured during operation of the refiner. Guidelines for doing this are presented together with a detailed description of the load sensor and some experimental results.

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Refining the Chemical Pulps

Manfredi

2024

Eucalyptus Kraft Pulp Refining

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Forces on bars in high-consistency mill-scale refiners: Effect of consistency

Cited by 11 publications

References 1 publication

A piezoelectric force sensor for mill-scale chip refiners

A piezoelectric force sensor for mill-scale chip refiners

Measuring Tangential Forces in a Pulp Refiner: A Novel Approach

Refining the Chemical Pulps

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