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WATER JET CONFERENCE - Waterjet Technology Association

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cutting rates, degree of bit wear, effect of cutting direction with respect to bedding and<br />

the overall economics of this cutting technique. In terms of bedding effects, previous tests<br />

performed on CSM linear cutting machine have concluded that direction of cutting in<br />

relation to the bedding has a significant influence on bit forces and wear, as well as the<br />

size distribution of the cuttings produced. Best cutting performance was obtained when<br />

bit was oriented to penetrate oil shale in a direction perpendicular to bedding planes (i.e.<br />

bedding planes are parallel to cutting surface). This effect will be investigated in more<br />

detail during tests with the drill rig.<br />

USE OF LABORATORY DRILLING AND BORING MACHINES FOR <strong>WATER</strong>-<strong>JET</strong><br />

CUTTING RESEARCH<br />

Both the laboratory drill rig and the 6 ft. diameter rotary cutting machines were<br />

designed to permit the use of water jets to assist mechanical cutting performance.<br />

For incorporating water jets, the rotary cutter includes a 6-inch diameter center<br />

rotating tube which runs the entire length of the main machine body. This tube provides<br />

access to the cutterhead through four, Ii2 inch holes drilled at the center portion of the<br />

cutterhead. In order to add water jets, a swivel can be installed on the back end of the<br />

center tube and high pressure water routed to the cutterhead using either stainless steel<br />

pipe or flexible high pressure hose located inside the center pipe. Once the high pressure<br />

water is brought to the cutterhead, final plumbing can be devised to route the water to<br />

individual nozzles mounted on selected cutters. Thus, the rotary cutting machine<br />

incorporates all the design features and means to permit easy installation of water jets on<br />

cutter bits.<br />

The drilling fixture is also equipped with a 6-inch center rotating tube which can<br />

be used to route the high pressure water to the cuttinghead.<br />

Various types of low and high pressure water pumps are available at CSM that<br />

can be used to generate the desired water pressures and volumes for use with either one<br />

of the two machines. Currently available are four low pressure triplex pumps and three<br />

high pressure duplex intensifier pumps, as well as a large selection of jet nozzles, holders<br />

and high pressure tubing. Through various combinations of these pumps, it is feasible to<br />

generate a wide range of water jet pressures and flow volumes.<br />

Test plans are currently being devised to install a 3 ft. diameter cutterhead on the<br />

drill rig for conducting water jet assisted drag bit cutting tests. These tests which will be<br />

performed within the next few months are designed to provide data to evaluate the effect<br />

of traverse speed on the degree of assistance which the water jet produces on bit forces<br />

and wear.<br />

CONCLUSIONS<br />

Both the laboratory drilling fixture and the rotary cutting machine provide unique<br />

capabilities for conducting research programs to evaluate and optimize the factors<br />

involved in water jet assisted mechanical cutting of rock. The extensive data acquisition<br />

and control capabilities of both machines will assure that tests are conducted under<br />

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