초록 ▼

The invention encompasses improvements in noise attenuation systems for reducing the audible noise level generated during earth boring operations using a hard surfaced rotary drill bit, and in dual bore-cutting elements for performing sequential first and second bore cutting to the design bore-gauge

The invention encompasses improvements in noise attenuation systems for reducing the audible noise level generated during earth boring operations using a hard surfaced rotary drill bit, and in dual bore-cutting elements for performing sequential first and second bore cutting to the design bore-gauge.

대표청구항 ▼

1. A rotary drilling system having a drill steel column for cutting bores in earth formations, comprising noise suppression means for significantly reducing the audible decibel level of drilling generated noise, said noise suppression system comprising annular means constructed and arranged for use

1. A rotary drilling system having a drill steel column for cutting bores in earth formations, comprising noise suppression means for significantly reducing the audible decibel level of drilling generated noise, said noise suppression system comprising annular means constructed and arranged for use in association with a drive steel column during drilling operations including a noise attenuating unit having a central bore to accommodate part of the steel column, said noise attenuating unit being a muffler device for placement in a bore hole circumscribing location and including sound absorbing material.