Your browser is not supported anymore.

We suggest changing from Internet Explorer to another option. The Internet Explorer browser is no longer supported by Microsoft. Please install or upgrade one of the browsers below.

Core Barrels: Getting to Know Your Outer Tube

posted by the Epiroc Exploration & OreBody Solutions team

March 18, 2024

In. few of our blogs, we’ve been looking at core barrels. A wire line core barrel typically consists of a double tube system that includes an inner tube and outer tube. We’ve looked at the parts that make up the inner tube assembly and the head assembly. In this blog, we will look at the parts of the outer tube and the role of each piece of equipment.

Why are we spending a lot of time looking at this equipment? Because in order to maintain good drilling performance, diamond drillers should have a thorough understanding of their drilling equipment. With that said, let’s look at the components.

Fordia 2021

Locking coupling:

The locking coupling serves as an adaptor between the square thread on outer tube and the tapered thread of the drill rod. The latches rest up against the tip of the pin end of the locking coupling, holding the head assembly in place. During drilling, the tang on the pin end of the locking coupling is in contact with the side of one of the latches to keep the inner tube assembly turning along with the outer tube.

Adaptor coupling:

This coupling provides the space for the latches to open fully and locks the landing ring into position inside the box end of the outer tube.

Landing ring:

This piece is positioned in the counter bore of the box thread in the outer tube. It provides a landing area for the inner tube assembly when you are pumping or lowering the tube. It is heat treated like the landing shoulder on the head assembly, and this helps both parts to resist the impact from the inner tube assembly when it comes to rest in the outer tube.

Outer tube:

The outer tube must be able to withstand a lot of stress because it is the piece that pushes and rotates the core bit. For this reason the O.T. is manufactured out from thicker material as compared to a drill rod. The pin end thread of the outer tube holds the inner tube stabilizer in position inside the reaming shell.

Inner tube stabilizer:

This piece sits in the reaming shell and keeps the inner tube centered and stable inside the bit, ready to receive the core sample.

The core barrel is a finely tuned piece of equipment where all the parts work in harmony to perform a certain job. Getting a good knowledge of the parts’ functions will help you figure out how to fix a problem if it arises. And don't forget one of our technical field service reps can alsways help you with advice and tips.


The Fundamental Guide to Core Bit Configurations

A great guide with tips to help you make the right choice of configuration options for your core bits.