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Inner Tube Damper Sub

IP.com Disclosure Number: IPCOM000241581D
Publication Date: 2015-May-13
Document File: 2 page(s) / 225K

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention is a sub within the swivel to prevent shearing of inner tube when excess spacing is set. The sub allows axial movement when a specific load is applied to the inner barrel, which is thin walled, and can also be configured to dampen axial vibrations.

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Inner Tube Damper Sub

Abstract:

This invention is a sub within the swivel to prevent shearing of inner tube when excess spacing is set.  The sub allows axial movement when a specific load is applied to the inner barrel, which is thin walled, and can also be configured to dampen axial vibrations.

Background:

Rigid inner tubes must be spaced away from contacting the internal structure of the corehead to allow independent rotation of the outer barrel during operation.  This spacing must be large enough to compensate for thermal expansion when different materials are used and loading during use downhole.  If the spacing is set too far the loading and vibrations can cause the inner barrel to overload and permanently stretch or break.

Description of the invention:

In this embodiment the sub is located between the bearing in the swivel and the inner barrel (Drawing 1 – Core Barrel & Damper Sub Cross-sections).  The sub has a spring which will deflect at a specific load to allow axial movement of the inner barrel before damage can occur (Drawing 2 – Damper Sub Cross-section).  The preferred spring medium would be belleville washers but could also be coiled, air or elastomer.  As the components move vibration damping could be created by using o-rings or similar items to create friction.  The sub components may be splined together to prevent rotation but would not be required  since the bearing allows rotation.

Drawing 1 – Core Barrel & Damper Sub Cross-sections

Drawing...