scholarly journals Ignition of Deposited Wood Dust Layer by Selected Sources

2020 ◽  
Vol 10 (17) ◽  
pp. 5779 ◽  
Author(s):  
Ivana Tureková ◽  
Iveta Marková
Keyword(s):  
Ignition Temperature ◽  
Ignition Time ◽  
Dust Sample ◽  
Spatial Arrangement ◽  
Quercus Petraea ◽  
Ignition Source ◽  
Dust Particles ◽  
Wood Dust ◽  
Sieve Analysis ◽  
Ignition Process

The main waste of wood sanding technology is wood dust. The formation of wood dust affects its behaviour. Wood dust can be in a turbulent form and behaves explosively or in a settled form where it becomes flammable. Dust particles are barely detectable by the naked eye, wood dust still presents substantial health, safety, fire and explosion risks to employees. This article deals with the evaluation of ignition temperature and surface temperature of deposited wood dust samples by selected ignition sources. The influence of selected physical properties of wood dust, the size of the contact area between the ignition source and the combustible material, the spatial arrangement during the ignition and the application time of the ignition source are analysed. The paper describes the behaviour of a 15 mm deposited layer of wood dust of spruce (Picea abies L.), beech (Fagus silvatica L.). oak (Quercus petraea Liebl.) caused by three potential ignition sources—a hot surface, an electric coil and a smouldering cigarette. Prior to the experimental determination of the ignition temperature, dust moisture content which did not significantly affect the ignition phase of the samples, as well as sieve analysis of tested samples were determined. The lowest minimum ignition temperature on the hot plate, as an important property of any fuel, because the combustion reaction of the fuel becomes self-sustaining only above this temperature, was reached by the oak dust sample (280 °C), the highest by the spruce dust sample (300 °C). The ignition process of wood dust was comparable in all samples, differing in the ignition time and the area of the thermally degraded layer. The least effective ignition source was a smouldering cigarette.

scholarly journals Fire Parameters of Spruce (Picea abies Karst. (L.)) Dust Layer from Different Wood Technologies Slovak Case Study

2022 ◽  
Vol 12 (2) ◽  
pp. 548
Author(s):  
Eva Mračková ◽  
Jarmila Schmidtová ◽  
Iveta Marková ◽  
Jana Jaďuďová ◽  
Ivana Tureková ◽  
...  
Keyword(s):  
Picea Abies ◽  
Ignition Temperature ◽  
Ignition Time ◽  
Dust Particles ◽  
Size Analysis ◽  
Wood Dust ◽  
Physical Parameters ◽  
Dust Layer ◽  
Significant Dependence ◽  
Minimum Ignition Temperature

The issue of the formation of wood dust particles in the work environment is still an actual topic in terms of its impact on employee health and the risk of fire or explosion in a woodworking operation. This article deals with the characteristics of spruce dust (Picea abies Karst. (L.)), which was taken from several types of wood technology. Experimental samples of spruce dust were taken from four types of sawing technologies, including grinding, briquetting and from the suction device container. The physical parameters of the samples taken were monitored and the particle size analysis was determined. The granulometric composition of the samples is significantly different. The sample of spruce wood dust from sawing has the most numerous fraction (250 µm), while the sample from grinding has the most numerous fraction 63–250 µm (87%).The aim of the paper was to monitor the minimum ignition temperature of the settled spruce dust layer and to look for a significant dependence of the minimum ignition temperature and ignition time on the type of spruce dust sample. A significant dependence was not confirmed. Significant moisture dependence of the samples was confirmed; the highest humidity was observed in the container, the lowest in sawing.

scholarly journals Evaluation of Marblewood Dust’s (Marmaroxylon racemosum) Effect on Ignition Risk

2021 ◽  
Vol 11 (15) ◽  
pp. 6874
Author(s):  
Miroslava Vandličkova ◽  
Iveta Markova ◽  
Katarina Holla ◽  
Stanislava Gašpercová
Keyword(s):  
Particle Size ◽  
Dust Particles ◽  
Wood Dust ◽  
Sieve Analysis ◽  
Granulometric Analysis ◽  
Analysis Measurement ◽  
Risk Research ◽  
Minimum Ignition Temperature ◽  
The Impact

The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size <100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).

Effect of the Particle Size of Wood Dust on Ignition Temperature

2017 ◽  
Vol 755 ◽  
pp. 38-43 ◽  
Author(s):  
Miroslava Vandlíčková ◽  
Jozef Vraniak
Keyword(s):  
Particle Size ◽  
Ignition Temperature ◽  
New Technologies ◽  
Wood Products ◽  
Wood Dust ◽  
Ignition Process ◽  
Minimal Action ◽  
Wood Processing ◽  
Human Need ◽  
Flammable Material

The development of the new technologies has also brought new possibilities of the wood processing, wood shaping and wood materials tending. By reason of increased human need for wood products the industry has shifted from the production in the workshops throught manufactures up to fabrications. This fact also causes increasing of the wood dust amount in the spaces of the production shops or halls, and by that also increased danger of the explosion of the wood dust. At the adequate initiatory source, sufficient amount of flammable material, oxidant and essential pressure, the explosion can occur and last for several miliseconds, therefore people rescue in the endangered spaces in case of explosion is impossible. One of the parameters which influence properties of the flammable wood dust is its particle size. The article deals with the particle size influence of the wood dust at its minimal temperature of ignition in the stired state. On the basis of the experimental measures the influence of the minimal action of the thermal energy for the activation of the ignition process of the wood dust in the stired state at the reacting of pressure and variousness of grit size is assessed.

scholarly journals Tropical Wood Dusts—Granulometry, Morfology and Ignition Temperature

2020 ◽  
Vol 10 (21) ◽  
pp. 7608
Author(s):  
Miroslava Vandličková ◽  
Iveta Marková ◽  
Linda Makovická Osvaldová ◽  
Stanislava Gašpercová ◽  
Jozef Svetlík ◽  
...  
Keyword(s):  
Ignition Temperature ◽  
Dust Particles ◽  
Wood Dust ◽  
Particle Sizes ◽  
Explosive Mixture ◽  
Tropical Wood ◽  
Granulometric Analysis ◽  
Tropical Woods ◽  
Automatic Mesh ◽  
Dipteryx Odorata

The article considers the granulometric analysis of selected samples of tropical wood dust from cumaru (Dipteryx odorata), padauk (Pterocarpus soyauxii), ebony (Diospyros crassiflora), and marblewood (Marmaroxylon racemosum) using a Makita 9556CR 1400 W grinder and K36 sandpaper, for the purpose of selecting the percentages of the various fractions (<63; 63; 71; 200; 315; 500 μm) of wood dust samples. Tropical wood dust samples were made using a hand orbital sander Makita 9556CR 1400 W, and sized using the automatic mesh vibratory sieve machine Retsch AS 200 control. Most dust particles (between 50–79%) from all wood samples were under 100 μm in size. This higher percentage is associated with the risk of inhaling the dust, causing damage to the respiratory system, and the risk of a dust-air explosive mixture. Results of granulometric fractions contribution of tropical woods sanding dust were similar. Ignition temperature was changed by particle sizes, and decreased with a decrease in particle sizes. We found that marblewood has the highest minimum ignition temperature (400–420 °C), and padauk has the lowest (370–390 °C).

Investigation of Reaction Products Obtained from Ignition Process of n-Heptane / Air Mixtures on Free Hot Surface

2017 ◽  
Vol 68 (5) ◽  
pp. 1035-1039
Author(s):  
Maria Mitu ◽  
Elisabeth Brandes
Keyword(s):  
Stainless Steel ◽  
Ignition Temperature ◽  
Ambient Pressure ◽  
Ignition Process ◽  
Reaction Products ◽  
Hot Surface

The ignition behaviour at ambient pressure (p0 between 98.0 kPa and 101.3 kPa) of different concentrations of homogenous n-heptane/air mixtures on stainless steel hot surface as well as the composition of the reaction products have been investigated. Although all reaction products are present in each burned n-heptane/air mixture, a correlation between the lowest ignition temperature and the quantitve composition of the reaction products is not obvious.

scholarly journals Study on the Ignition Process and Characteristics of the Nitrate Ester Plasticized Polyether Propellant

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xiaoting Yan ◽  
Zhixun Xia ◽  
Liya Huang ◽  
Likun Ma ◽  
Xudong Na ◽  
...  
Keyword(s):  
Grain Size ◽  
Energy Density ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Temperature ◽  
Ignition Delay Time ◽  
Ignition Process ◽  
Ignition Energy ◽  
Nitrate Ester ◽  
Nepe Propellant

In this study, a CO2 laser ignition experimental system was built to study the ignition process and characteristics of the Nitrate Ester Plasticized Polyether (NEPE) propellant. The effect of the energy density, ingredients, and the grain size distribution of the propellant on the ignition process was investigated using a CO2 laser igniter, a high-speed camera, and a tungsten-rhenium thermocouple. Four types of NEPE propellants were tested under different laser heat fluxes, and the ignition delay time, the ignition temperature, and the ignition energy were obtained. Experimental results show that the ignition process of the NEPE propellant can be divided into three stages, namely the first-gasification stage, the first-flame stage, and the ignition delay stage. When the energy density is lower than the ignition energy threshold, the ignition process cannot be achieved even under continuous energy loading. The increase of the energy density can lead to the decrease of the ignition delay time but has little effect on the ignition temperature. The ingredients and grain size distribution have great effects on both the ignition delay time and the ignition temperature. The grain size effect of aluminum is the largest compared with that of Ammonium Perchlorate (AP) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), while the grain size effect of AP is larger than that of HMX.

scholarly journals Influence of Exhaust System Setup on Working Zone Pollution by Dust during Sawing of Particleboards

2020 ◽  
Vol 17 (10) ◽  
pp. 3626 ◽  
Author(s):  
Bartosz Pałubicki ◽  
Luďka Hlásková ◽  
Tomasz Rogoziński
Keyword(s):  
Air Pollution ◽  
Exhaust System ◽  
High Impact ◽  
Dust Concentration ◽  
Dust Particles ◽  
Extraction System ◽  
Wood Dust ◽  
Dust Extraction ◽  
Working Zone ◽  
Machine Work

Air pollution by wood dust in furniture production sites is an important hygiene issue. The dust is created by all types of wood and wood-based material machining, and its concentration in the working zone surrounding the machining stand depends on the effectiveness of the dust exhaust system. In present research, three setups of the dust extraction system for a conventional table sawing machine are considered while machining particleboards. The results showed a high impact of the exhaust system connection setup on the dust concentration in the air surrounding the sawing machine work stand. The use of both main and auxiliary sawdust extraction connectors together ensured the highest clearness of the air, with only 0.5 mg/m3 of dust concentration. Closing the upper hood leads to a concentration five times higher, while disconnecting it results in a ten times higher dust content. The finest dust particles (<1 µm), however, are the most numerous in the case of closing the hood.

Investigation of the spark ignition enhancement in a supersonic flow

2014 ◽  
Vol 28 (29) ◽  
pp. 1450226 ◽  
Author(s):  
Zun Cai ◽  
Zhen-Guo Wang ◽  
Ming-Bo Sun ◽  
Hong-Bo Wang ◽  
Jian-Han Liang
Keyword(s):  
Ignition Time ◽  
Spark Ignition ◽  
Dominant Factor ◽  
Ignition Process ◽  
Operation Condition ◽  
Flame Kernel ◽  
Operation Conditions ◽  
Key Factor ◽  
Lean Fuel ◽  
Spark Energy

Ethylene spark ignition experiments were conducted based on an variable energy igniter at the inflow conditions of Ma = 2.1 with stagnation state T0 = 846 K , P0 = 0.7 MPa . By comparing the spark energy and spark frequency of four typical operation conditions of the igniter, it is indicated that the spark energy determines the scale of the spark and the spark existing time. The spark frequency plays a role of sustaining flame and promoting the formation and propagation of the flame kernel, and it is also the dominant factor determining the ignition time compared with the spark energy. The spark power, which is the product of the spark energy and spark frequency, is the key factor affecting the ignition process. For a fixed spark power, the igniter operation condition of high spark frequency with low spark energy always exhibits a better ignition ability. As approaching the lean fuel limit, only the igniter operation condition (87 Hz and 3.0 J) could achieve a successful ignition, where the other typical operation conditions (26 Hz and 10.5 J, 247 Hz and 0.8 J, 150 Hz and 1.4 J) failed.

scholarly journals THE MEASUREMENT AND DISTRIBUTION OF WOOD DUST

2010 ◽  
Vol 41 (1) ◽  
pp. 25 ◽  
Author(s):  
Andrea Rosario Proto ◽  
Giuseppe Zimbalatti ◽  
Martino Negri
Keyword(s):  
Health And Safety ◽  
Qualitative Assessment ◽  
Dust Particles ◽  
Wood Dust ◽  
High Concentration ◽  
Dust Emissions ◽  
Carcinogenic Agents ◽  
Prevention Model ◽  
Number Of Particles

In Italy, the woodworking industry presents many issues in terms of occupational health and safety. This study on exposure to wood dust could contribute to the realization of a prevention model in order to limit exposure to carcinogenic agents to the worker. The sampling methodology illustrated the analysis of dust emissions from the woodworking machinery in operation throughout the various processing cycles. The quantitative and qualitative assessment of exposure was performed using two different methodologies. The levels of wood dust were determined according to EN indications and sampling was conducted using IOM and Cyclon personal samplers. The qualitative research of wood dust was performed using an advanced laser air particle counter. This allowed the number of particles present to be counted in real time. The results obtained allowed for an accurate assessment of the quality of the dust emitted inside the workplace during the various processing phases. The study highlighted the distribution of air particles within the different size classes, the exact number of both thin and ultra-thin dusts, and confirmed the high concentration of thin dust particles which can be very harmful to humans.

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