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Accession Number:
ADA235873
Title:
Development of a Seawater Hydraulic Rock Drill
Descriptive Note:
Final rept. Sep 1985-Sep 1990
Corporate Author:
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
Report Date:
1991-03-01
Pagination or Media Count:
98.0
Abstract:
Under the Underwater Construction System program, a seawater hydraulic tool system called the Multi-Function Tool System MFTS was developed. An objective of the MFTS development was to provide Underwater Construction Team divers with tools that meet their operational needs and were optimized for both the diver and the environment. A seawater hydraulic rock drill has not been issued because its performance is not predictable and its operation is not reliable. Extensive testing has isolated the problem to the impact mechanism and the timing of the cycle. Leakage of the supply poppet and the drive plunger as well as pressure pulsations from the rapid closing of the supply poppet have an undetermined negative affect on cycle operation. Cycle performance is not repeatable from test to test suggesting a transient or threshold condition that the drill is not always able to overcome. Additional development of the water lubricated impact mechanism is needed to investigate and correct these problems. While sea water is an attractive alternative to oil, it promotes sea water corrosion in metals, and the low viscosity of seawater offers minimal lubrication and high leakage rates compared to oils. These factors complicate the design of limiting material selection to those satisfying corrosion and lubrication criteria. In addition, close tolerance machining is necessary.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
