1,721,035 research outputs found
Plain water jet noise emission: influence of hydraulic parameters and stand-off distance
No full textThe paper deals with the influence of the hydraulic parameters (pressure and nozzle diameter) on the noise emitted by plain water jet under different settings of the stand-off distance. The results of the research showed that the two hydraulic parameters have a significant influence on the noise generated by different jet portions. Some general recommendations regarding health and safety conditions of the worker involved in the operations have been given considering the combined influence of the operative parameters
Effect of the stress state on waterjet performance in rock slotting
Full text linkThe economic benefit resulting from the application of waterjet technology in underground and surface quarrying of dimension stone chiefly depends on slotting rate. The performance achievable in the field is connected with the operating features of the machine, the characteristics of the material and the tensional state of the rock massif. In order to assess the influence of the state of stress of the massif on the slotting rate, tests with oscillating nozzle have been carried out on samples subjected to a static load, either in the direction of the compressive force or perpendicular to it. Results are illustrated and discussed and conclusions are drawn regarding the effect of the tensional state of the rock on material removal rate
Effect of the Rock Stress on the Water Jet Cutting Performance
Full text linkUnderground quarrying is rarely adopted for granite extraction due to the difficulties in the implementation of traditional technologies (drilling and explosive). As alternative to drilling and explosive, the combination of diamond wire and water jet seems to be the most promising available technology. The cutting performance achievable with the water jet technology depends on the operative parameters, the material characteristics and the state of stress within the rock massif. To assess the effect of the state of stress on the cutting rate, laboratory tests have been performed with an oscillating water jet machine on granite samples subjected to a static load. The stress distribution in the layer of rock to be removed has been evaluated by numerical simulation with the FLAC code (Fast Lagrangian Analysis of Continua). The correlation between the results of the cutting tests and the numerical models of the rock samples has been inferred. Starting from a conceptual model, which theoretically describes the relationship between the cutting rate and the stress, a step function was defined that indicates the ranges of stress where predefined values of the cutting rate are workable
Stato delle Conoscenze sull’abbattimento delle rocce dure ed abrasive mediante utensili assistiti da getti d’acqua ad alta pressione
No full textNoise generation in water jet technology
No full textWater-jet technology is highly versatile and adaptable owing to the fact that its
operating parameters (in particular, hydraulic pressure, flow rate and stand-off
distance) can be adjusted to obtain the most suitable configuration depending on
the specific application. Such characteristics give it a significant advantage which
has led to the spread of this technology into numerous industrial sectors,
including mineral, civil and environmental engineering. However, there are
drawbacks regarding noise and therefore, the versatility of the technology could
lead to severe health and safety issues in the workplace. This article presents the
results of a study aimed at characterising the acoustic emission of water-jet
technology in relation to key operating parameters. The results suggest some
modification to operating practice in order to reduce the noise level of water-jet
applications
A new technology for the disposal of worn car tires
No full textAn enormous quantity of used tires are produced worldwide, many of which are landfilled. However the bulkiness of scrap tires creates major problems for their disposal in landfill sites. An alternative option from both an operational and economic standpoint is to dismantle and recycle both the steel wire and rubber. Waterjet is a potentially suitable technology for achieving this goal. An experimental investigation has been conducted on conventional car tires at DIGlTA's waterjet laboratories with the aim of obtaining useful correlations for rubber removal rate as a function of the main operating parameters (pressure and water flow rate, nozzle exit velocity, stand-off distance). Based on the results of these experiments, the technical and economic aspects concerning this technology are evaluated. © BHR Group 2008 Water Jetting 19
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