Bar force measurement in low consistency refining: the effect of plate pattern

2018 ◽  
Vol 33 (2) ◽  
pp. 210-219
Author(s):  
R. Harirforoush ◽  
J. Olson ◽  
P. Wild
Keyword(s):  
Coefficient Of Friction ◽  
Force Measurement ◽  
Piezoelectric Sensor ◽  
Edge Length ◽  
Thermomechanical Pulp ◽  
Pulp Fibers ◽  
Shear Forces ◽  
Tear Index ◽  
Softwood Kraft Pulp ◽  
The Mean

Abstract The effect of plate pattern on forces applied to pulp fibers by refiner bars in low consistency refining is investigated in an AIKAWA 16-inch single-disc refiner. These forces are measured using a custom-built piezoelectric sensor. Trials are conducted using SPF softwood thermomechanical pulp, northern bleached softwood kraft pulp, and aspen hardwood thermomechanical pulp at 3.3 to 3.6 % consistency at rotational speeds of 1200 and 1400 rpm. The pulp is sampled at regular intervals, and the length-weighted fiber length, freeness, tear index, and tensile index are measured for each sample. The results show that the plate with higher bar edge length results in lower mean peak normal and shear forces. The mean peak normal and shear forces at the onset of fiber cutting depend on rotational speed, pulp furnish and plate pattern, and these parameters are lower for a plate pattern with higher bar edge length. In addition, the mean coefficient of friction is a function of plate gap, pulp furnish, and plate pattern. The plate having higher bar edge length results in higher mean coefficient of friction.

Indications of the onset of fiber cutting in low consistency refining using a refiner force sensor: The effect of pulp furnish

2018 ◽  
Vol 33 (1) ◽  
pp. 58-68 ◽  
Author(s):  
R. Harirforoush ◽  
J. Olson ◽  
P. Wild
Keyword(s):  
Fiber Quality ◽  
Force Sensor ◽  
Strength Properties ◽  
Thermomechanical Pulp ◽  
Pulp Fibers ◽  
Increase Energy Efficiency ◽  
Time Domain Signal ◽  
Softwood Kraft Pulp ◽  
The Time Domain ◽  
Process Detection

Abstract Detection of the onset of fiber cutting is beneficial in low consistency refining as it may prevent reduction of average fiber length, optimize fiber quality improvements by operating at gaps just wider than the critical gap, avoid decreasing the strength properties of paper, and increase energy efficiency. The objective of this study is to understand the effect of pulp furnish on measured bar forces and, more specifically, on the detection of fiber cutting. Bar forces, i. e. forces applied to pulp fibers by the refiner bars, are measured with a custom-designed piezoelectric force sensor. Trials were conducted with an AIKAWA 16-in. single-disc refiner using hemlock/balsam softwood thermomechanical pulp, SPF softwood thermomechanical pulp, northern bleached softwood kraft pulp, and aspen hardwood thermomechanical pulp at 3.0 to 3.5 % consistency at rotational speeds of 1200 and 1400 rpm. The power of the time domain signal of the measured forces is introduced as an indicator of the onset of fiber cutting. Our results show that this new fiber cutting metric is a sensitive and reliable metric for determination of fibre cutting for a range of pulp furnishes. The study suggests that the refiner force sensor has potential to be exploited for in-process detection of fiber cutting.

Use of thermomechanical pulp fibers from waste woods for making eco-friendly cushioning material

TAPPI Journal ◽  
2010 ◽  
Vol 9 (7) ◽  
pp. 15-21 ◽  
Author(s):  
JI-YOUNG LEE ◽  
CHUL-HWAN KIM ◽  
JEONG-MIN SEO ◽  
HO-KYUNG CHUNG ◽  
KYUNG-KIL BACK ◽  
...  
Keyword(s):  
Impact Test ◽  
Product Distribution ◽  
Expanded Polystyrene ◽  
Thermomechanical Pulp ◽  
Fiber Structure ◽  
Pulp Fibers ◽  
Cationic Starch ◽  
Thermal Insulating ◽  
Surface Sizing ◽  
The Impact

Eco-friendly cushioning materials were made with thermomechanical pulps (TMPs) from waste woods collected from local mountains in Korea, using a suction-forming method without physical pressing. The TMP cushions had superior shock-absorbing performance, with lower elastic moduli than expanded polystyrene (EPS) or molded pulp. Even though the TMP cushions made using various suction times had many voids in their inner fiber structure, their apparent densities were a little higher than that of EPS and much lower than that of molded pulp. The addition of cationic starch contributed to an increase in the elastic modulus of the TMP cushions without increasing the apparent density, an effect which was different from that of surface sizing with starch. In the impact test, the TMP cushions showed a more ductile pattern than the brittle EPS. The porosity of the TMP cushion was a little less than that of EPS and much greater than that of molded pulp. The porous structure of the TMP cushions contributed to their excellent thermal insulating capacity, which was equivalent to that of EPS. In summary, the TMP packing cushions showed great potential for surviving external impacts during product distribution.

Action Mechanism of the Improvement of Printability for Eucalypt Bleached Kraft Pulp Pretreated by Cellulase

2013 ◽  
Vol 779-780 ◽  
pp. 294-301
Author(s):  
Wan You Tang ◽  
Li Chen ◽  
Zheng Jian Zhang
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Kraft Pulp ◽  
Pulp Fiber ◽  
Fiber Morphology ◽  
Strength Index ◽  
Bleached Kraft Pulp ◽  
Tear Index ◽  
Pulp Sample ◽  
The Mean

Enzymatic refining of eucalypt bleached kraft pulp with the cellulase NOV476 was studied. The effects of this cellulase on the physical properties of pulp, fiber morphology and fiber appearance of the eucalypt bleached kraft pulp in different application conditions were discussed. The results show that, with the increase in the amount of enzyme, tensile strength index, burst index and TEA index of paper are increased and then decreased; elongation and tear index of paper have been declining, Zeeil tensile strength index has been an upward trend. Without beating the pulp sample, gradually increases as the amount of enzyme, the average fiber length and the average fiber width are gradually reduced, while mean kink index substantially constant. Number of vessels in fiber overall reduced tendency reaches a minimum in the amount of enzyme 0.5μ/g, the phenomenon is most obvious. In the same conditions of beating time, gradually increases as the amount of enzyme, the average fiber length is gradually reduced, an average fiber width is gradually increased, the mean kink index reaches a maximum in the amount of enzyme is 0.5μ/g. Number of vessels in fiber overall reduced trend.

scholarly journals 1,2,3,4-Butanetetracarboxylic Acid Cross-Linked Softwood Kraft Pulp Fibers for Use in Fluff Pulp Applications

2014 ◽  
Vol 9 (3) ◽  
pp. 155892501400900
Author(s):  
Kristoffer Lund ◽  
Harald Brelid
Keyword(s):  
Kraft Pulp ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Pulp Fibers ◽  
Fiber Networks ◽  
Polycarboxylic Acids ◽  
Fiber Wall ◽  
Softwood Kraft Pulp ◽  
Cross Linker ◽  
Butanetetracarboxylic Acid

Cross-linked fluff pulp fibers for use in, for example, acquisition layers in absorption products can be found in the patent literature. Cross-linking improves properties such as the wet resilience of fluff pulp fiber networks. Among the more commonly seen cross-linkers are polycarboxylic acids, such as 1,2,3,4-butanetetracarboxylic acid (BTCA). These acids form ester bonds with the hydroxyl groups in the fiber wall. In this study, softwood kraft pulp fibers were cross-linked with BTCA. The swelling behavior of the fibers and properties related to acquisition in absorption products were studied. It was found that the water retention value (WRV) decreased as a consequence of the introduced cross-linker. After deprotonization of a large part of the introduced carboxylic acids, the WRV increased, but the cross-linker was still able to limit significant swelling of the fiber wall. The wet bulk under load of fiber networks, composed of cross-linked fibers, generally increased with a decrease in WRV. Furthermore, it was found that the property development obtained after a cross-linking reaction with BTCA may be predicted by introducing a relative reaction intensity, RIrel, that takes into account both time and temperature in the curing step. This shows that the time and temperature in the curing step are interchangeable.

The effect of elasticity in powder metal gears on tooth loading and mean coefficient of friction

2017 ◽  
Vol 232 (11) ◽  
pp. 2023-2031 ◽  
Author(s):  
Per Lindholm ◽  
Mario Sosa ◽  
Ulf Olofsson
Keyword(s):  
Coefficient Of Friction ◽  
Loss Factor ◽  
Power Loss ◽  
Contact Length ◽  
Powder Metal ◽  
Gear Mesh ◽  
Single Tooth ◽  
The Mean ◽  
Gear Contact ◽  
Load Behavior

Powder metal gears have a lower density than conventional steel gears due to their intrinsic porosity from the manufacturing process. This also results in a lower elasticity leading to larger deformations and lower contact pressure in a gear contact. By using different modelling tools (namely FEA and available commercial software), the load behavior along the line of action is studied to compare the influence of lower elasticity with standard wrought steel elasticity for FZG-C type gears. A further step is taken analyzing this effect on the mean coefficient of friction through the recalculation of the gear mesh power loss factor. Conclusions observed are differences in load distribution and marginal differences in the gear mesh power loss factor when comparing sintered and wrought steel FZG-C type gears. Sintered steel showed a marginally longer line of action and simultaneously a decrease of the single tooth contact length when compared to wrought steel, while differences in the gear mesh power loss factor proved non-essential due to the spread in previously measured experimental data.

Feasibility Study of Force Measurement for Multi-digit Unconstrained Grasping via Fingernail Imaging and Visual Servoing

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Navid Fallahinia ◽  
Stephen A. Mascaro
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Field Of View ◽  
Imaging Method ◽  
Shear Forces ◽  
Maximum Value ◽  
6 Degrees Of Freedom ◽  
Finger Pad ◽  
Rms Errors

Abstract A fingernail imaging has been shown to be effective in estimating the finger pad forces along all three directions simultaneously in previous works. However, this method has never been used for the purpose of force measurement during a grasping task with multiple fingers. The objective of this paper is to demonstrate the grasp force-sensing capabilities of the fingernail imaging method integrated with a visual servoing robotic system. In this study, the fingernail imaging method has been used in both constrained and unconstrained multi-digit grasping studies. Visual servoing has been employed to solve the issue of keeping fingernail images in the field of view of the camera during grasping motions. Two grasping experiments have been designed and conducted to show the performance and accuracy of the fingernail imaging method to be used in grasping studies. The maximum value of root-mean-square (RMS) errors for estimated normal and shear forces during constrained grasping has been found to be 0.58 N (5.7%) and 0.49 N (9.2%), respectively. Moreover, a visual servoing system implemented on a 6-degrees-of-freedom (DOF) robot has been devised to ensure that all of the fingers remain in the camera frame at all times. Comparing unconstrained and constrained forces has shown that force collaboration among fingers could change based on the grasping condition.

scholarly journals Alkali Extraction of Kraft Pulp Fibers: Influence on Fiber and Fluff Pulp Properties

2012 ◽  
Vol 7 (2) ◽  
pp. 155892501200700 ◽  
Author(s):  
Kristoffer Lund ◽  
Karin Sjöström ◽  
Harald Brelid
Keyword(s):  
Kraft Pulp ◽  
Pulp Fibers ◽  
Fiber Network ◽  
Alkali Extraction ◽  
Flexible Fiber ◽  
Softwood Pulp ◽  
Softwood Kraft Pulp ◽  
Patent Literature ◽  
Network Strength ◽  
Birch Kraft Pulp

The importance of hemicelluloses for the papermaking properties of pulp fibers is well documented. In the patent literature, it can be seen that there is also an interest in this type of modification of pulp fibers for use in absorption products. In this study, a Scandinavian softwood kraft pulp and a birch kraft pulp were alkali extracted at 3 different concentrations of NaOH (2%, 4% and 8% NaOH in the suspension). The alkali extraction removed a large part of the hemicelluloses from the pulp fibers and decreased the content of the charged groups. After extraction, the pulps were dried in the form of sheets (approx. 600 g/m2). The alkali extracted pulp fibers exhibited a greater decrease in swelling when re-wetted than untreated pulp. A significant increase in the curl index after extraction with 4% and 8% NaOH was also noted. The tensile strength index of the formed sheets increased at the lowest concentration of NaOH and, at the higher concentrations, a decrease was observed. The pulp sheets were dry defibrated at different defibration intensities and the performance of the resulting pulps in fluff pulp applications was studied. The air-laid fiber networks of softwood pulp fibers showed higher network strength than the networks of birch pulps. The birch pulp extracted at the highest alkali level tended to give the highest network strength. The results from the network strength tests also indicated that the increased curl of the fibers from the softwood pulp extracted at the highest alkali level rendered a more flexible fiber network. In water absorption tests, the alkali treated softwood fibers tended to give networks with a somewhat enhanced water holding capacity under pressure.

Some Physical and Mechanical Properties of Sugarcane Trash Relating to the Criteria Design of a Sugarcane Trash Chopping Machine

2014 ◽  
Vol 931-932 ◽  
pp. 1574-1581
Author(s):  
Nirattisak Khongthon ◽  
Somposh Sudajan
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Coefficient Of Friction ◽  
Physical And Mechanical Properties ◽  
Unit Weight ◽  
Shearing Force ◽  
Moisture Contents ◽  
The Mean ◽  
Static Coefficient Of Friction ◽  
Static Coefficient

The physical and mechanical properties of sugarcane leaves were necessary for the design consideration of the relating storage, handling and processing equipment. The sugarcane trash at moisture contents of 23.40 and 73.91 % w.b. were used for this study. The mean length and unit weight of sugarcane trashes were 168.63 cm and 65.87 grams respectively. The average number of leaf of each sample was 4. The mean diameter of the thrash top, width and thickness increased with the increase of moisture from 23.40 and 73.91 % w.b.. The average leaf angles (β) relative to the horizontal plane of the first left leaf, second left leaf, first right leaf and second right leaf were 65.10, 73.36, 71.07 and 78.26 degrees for 73.91 % w.b., and 66.33, 73.50, 67.50 and 75.83 degrees for 23.40 % w.b. respectively. When the moisture content increased from 23.40 to 73.91% w.b., the static coefficient of friction increased from 0.30 to 0.43, 0.38 to 0.41, 0.30 to 0.37 and 0.54 to 0.66 for plywood, mild steel, galvanized iron and rubber plate respectively. The least static coefficient of friction occurred on the galvanized iron plate. The results from experimenting on mechanical properties showed that the maximum shearing force increased with the increase in moisture content from 23.40 to 73.91% w.b. respectively. The maximum shearing force was 360.15 and 457.32 N for moisture contents of 23.40 and 73.91% w.b.. The maximum tensile force decreased toward upper region of the leaf for both 23.40 and 73.91% w.b.. The results of this study would be useful for the design and optimization of the equipment associated with harvesting, threshing, chopping and processing.

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