In the drilling process, the double pipe drilling tool in which the
outer pipe rotates and the inner pipe does not rotate is called a
single acting double pipe drilling tool. Since the single-acting
double-tube drilling tool avoids the mechanical vibration of the
rock core by the friction vibration generated by the rotation of
the drill, the core quality is high.
The upper joint has a movable environmental protection path, and
the groove is arranged on the joint to ensure the diameter of the
alloy piece. The distance between the spring seat and the step
inside the drill bit is adjusted by the screw and the lock nut; and
the length difference between the inner and outer tubes itself is
also controlled. The single-action form has a spherical structure,
a single-bearing structure and a double-bearing structure (Fig. 2,
Fig. 3, Fig. 4). Its working principle: the drilling machine is
used to transmit power to make the drilling tool rotate, and the
outer tube is connected to the cutting edge of the drill bit or the
grinding material is ground. The rock breaks it, and the inner tube
(ie, the core tube) remains stationary during the drilling process,
so that the removed core avoids disturbance and can remain
substantially in its original state.
Single-action double-tube drilling tools types and characteristics
1. Water-proof single-action double-tube drilling tools
The drilling tool consists of five parts: outer pipe joint, single
action device, inner and outer pipe, card center device and special
In addition to single action, the drill has a good guiding,
water-proof and card center device. The outer tube can be connected
to a special carbide drill or steel drill bit for drilling into
different salt mine layers.
2. Piston type single acting double pipe drilling tools
This type of drilling tool is a special core drilling tool for the
exploration of talc mines. It is mainly composed of five parts:
water distribution joint, single action bearing, special
semi-synthetic pipe, rubber piston and step drill bit.
When using, punch, do not put the steel ball into the hole, and the
flushing liquid directly enters the half pipe to push the piston to
the step at the bottom of the bit. At this time, the rinsing liquid
flows into the annular gap of the inner and outer tubes from the
two return holes at the lower end of the single-action shaft, and
enters the bottom of the hole through the water outlet hole on the
step drill bit, carrying the rock powder returning to the orifice.
After punching and sweeping, put in the steel ball. When drilling,
the rinsing liquid enters the bottom of the hole from the gap
between the two outlet pore inner tubes on the water joint and the
water outlet hole on the step drill bit.
3. Pressure card type single acting double tube
This type of drilling tool consists of main components such as
rotary, single action, card core, return water and drill bit. The
drill is suitable for relatively intact, jointed or fibrous rock
ore. Such as asbestos and so on.
The drill is of the piston type and the ball clamp type.
After the two types of drilling tools are drilled into the
borehole, do not put the steel ball into the hole. After the pump
is flushed, the hole is drilled normally. After the end of the
mining process, when the rock core is mined, the steel ball is put
into the tank and the pump is opened into the tank. The rinsing
fluid is forced to force the core breaker to strongly capture the
4. Claw spring type single action double pipe drilling tools
The drilling tool is suitable for drilling in rock formations such
as thin coal seams with soft and hard alternating, frequent and
unstable, and less than 6 grades.