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Techniques to Increase Water Pressure for Improved Water-jet- assisted Cutting.

Authors
Kovscek-PD; Taylor-CD; Thimons-ED
Source
MISSING :10 pages
Link
NIOSHTIC No.
10006207
Abstract
High-pressure streams of water, known as water jets, can be used to improve the cutting efficiency of mechanical bits. During prior testing by the Bureau of Mines, the cutting performance of a longwall shearer, equipped for water-jet-assisted cutting was evaluated. The performance of the shearer did not improve while using water jet assist because the pressure of the water delivered to the rock surface was inadequate. The study, described in this report, resulted in a determination of the major cause of water pressure loss on the shearer, and an evaluation of the techniques for increasing the water pressure at the rock surface. The results show that the major pressure loss, which occurred between the nozzle and rock surface, is directly affected by the amount of fluid turbulence that develops just upstream from the nozzle. Preventing a sudden change in the direction of the flow channel can increase the stagnation pressure as much as 400 pct. Smoothing the surface of the flow channel in the shearer bit block would increase the stagnation pressure delivered to the rock surface by 35 pct.
Publication Date
19880101
Document Type
IH; Report of Investigations;
Fiscal Year
1988
NTIS Accession No.
NTIS Price
Identifying No.
RI 9201
NIOSH Division
PRC;
Source Name
MISSING
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