RC40 RC45 RC50 RC Hammer RC Drilling Bits for gold samples reverse circulation collecting

RC40 RC45 RC50 RC Hammer RC Drilling Bits for gold samples reverse circulation collecting

The compressed air or Gas lift reverse circulation, also known as compressed air reverse circulation, the drilling tool used is divided into two parts, the upper part is a double-wall drill pipe, and the lower part is a single-wall drill pipe (also known as liner), which is connected by a gas-water mixer (gas lift joint).

The reverse circulation drilling principle is that the compressed air is continuously sent to the air-water mixer through the annular channel between the inner and outer pipes of the double-wall drill pipe, so that the air is mixed with the flushing liquid in the drill pipe to form a relatively small density of the mixed liquid column, and the pressure difference is generated between the liquid column outside the drill pipe, and a reverse circulation is formed under the action of this pressure difference, so that the mixed liquid in the inner drill pipe carries the cuttings out of the hole.

The bubbles in the air mixture continue to expand due to the gradual decrease of external pressure during the rising process, so that the speed of the air mixture rises faster and faster (the expansion work of the compressed air is converted into the kinetic energy of the liquid). This method cannot be used in the opening stage, and must wait for the gas-water mixer to go down to a certain depth (generally the hole depth is more than 25m), and the pressure difference between the liquid column inside and outside the whole pipeline can be sufficient to form a reverse circulation. As long as the pressure of the air compressor is sufficient, there is no limit to the hole depth for this method.

Features:

1. RC40, RC45, RC50:

   • Meaning: Casing diameters (in millimeters).

   • Function: These specify the outer diameter of the temporary steel casing used to line the borehole and prevent collapse.

   • Sizes: RC40 = ~40mm, RC45 = ~45mm, RC50 = ~50mm. (Actual internal/external diameters vary slightly by manufacturer).

2. RC Hammer:

   • Meaning: The down-the-hole (DTH) hammer used within the RC system.

   • Function: A pneumatically (compressed air) powered hammer that provides the percussive force to break rock. It sits directly behind the drilling bit.

   • Compatibility: RC hammers are designed to fit inside specific casing sizes (e.g., an RC40 hammer fits inside RC40 casing, an RC50 hammer inside RC50 casing).

3. RC DRILLING BIT:

   • Meaning: The drill bit specifically designed for use with an RC Hammer and Casing system.

   • Function: Attaches to the front of the RC Hammer. It cuts/breaks the rock and typically has a larger diameter than the casing itself.

   • Design: Features large flushing ports to allow cuttings to be blown back up the annulus between the drill string/casing and the borehole wall. The bit's gauge (outer diameter) is designed to clear the inner diameter of the casing it's used with.

How They Work Together:

1. The RC Hammer (e.g., sized for RC50 casing) is attached to the drill string.

2. The RC Drilling Bit (e.g., sized for RC50 casing) is attached to the front of the hammer.

3. This assembly rotates inside the Casing (e.g., RC50).

4. Compressed air powers the hammer, driving the bit to break the rock.

5. The same air blows rock cuttings up the borehole annulus (outside the casing).

6. The casing is advanced (usually driven or vibrated) behind the bit to support the hole.

In Summary:

• RC40/RC45/RC50: Specify the casing size (diameter) used.

• RC Hammer: The percussive tool that fits inside that specific casing size.

• RC Drilling Bit: The cutting tool attached to the hammer, designed to work with that specific casing/hammer size.

These components are part of a system designed for efficient, stable drilling in challenging ground conditions where hole collapse is a risk.