Rockmore International's 5-in.-range ROK
500DH DTH hammer, the newest entry in
its Deep Hole series, is intended to drill 5.5
to 6-in. (140 to 152-mm) diameter holes
and designed to increase drilling effective-ness and efficiency in deep hole applica-tions that may exceed 1,000 ft (300 m) in
depth and include high volumes of water.
The hammer has been designed to handle
such challenges by incorporating new air-flow and component design advancements,
primarily in the air ports of the wear sleeve
and piston. The ROK 500DH is rated for
use with large compressors (24.1 bar / 350
psi at 25.2 m3
/min / 890 scfm); however, it
can accept greater air volumes and pres-sures from larger air compressor packages.
The upper and lower hammer air chambers
of the 500DH have been modified to
achieve optimum drilling efficiency. The
advanced piston design also offers maxi-mum blow energy with each stroke to the
bit, allowing for superior hammer and bit
penetration rates in all drilling conditions.
A new bit shank was developed in con-junction with the hammer's new bit-reten-tion system, eliminating the need for bit
retaining rings present in conventional
hammer designs. The bit is retained in the
driver sub by lobes located on the bit
shoulder. If the bit breaks from the shank
body during drilling operations, the bit
head can be retracted from the hole,
retained by the lobes on the bit and driver
sub, thus eliminating downtime. Because
foot-valve breakages on DTH bit shanks
during drilling operations are catastrophic
in deep hole drilling—the hammer will
cease to function immediately after such a
failure—the traditional foot valve, or blow tube component, also has been eliminated
in the DH500 shank concept.
An innovative design reduces the num-ber of hammer components, thus reducing
the amount of component wear points,
making hammer service simpler and less
expensive. Lead threads on the top sub
and driver sub ensure easy coupling and
uncoupling of the hammer.
www.rockmore-intl.com
As featured in Womp 2012 Vol 09 - www.womp-int.com
