Self-drilling anchor system product introduction-coupler

Self-drilling anchor system is an efficient construction technology that integrates drilling, grouting, and anchoring. It’s widely used in complex geological conditions such as weak surrounding rock, fault fracture zone, high ground stress, and large deformation.

Self-drilling anchor system can be used in tunnels, roadways, or other narrow construction face because of its arbitrary length. To ensure the hollow bar quality after extension, the design of couplers also have strict requirements:

1. Strength
When coupler is used to extend the length, it may become the weak point of the entire anchor solid. If the coupler strength is too low, it will break when the rock layer changes, which will affect the project safety.

To avoid these occur, Kelleg's couplers of each specification are tested and verified many times. To ensures that the combined force value of the coupler and hollow bar is not lower than hollow bar standard force value. Each batch of products also has strict sampling requirements.

2. Tightness
Hollow bar and coupler are generally the clearance fit. This will cause slurry or water to leak out the coupler, thereby reducing pressure at the drill bit and affecting drilling chip removal or grouting.

To meet customer's requirements for tightness of coupler, Kelleg designed different sealing structures for multi-specification couplers. Conjunction with the chamfer at the end of anchor bar, the sealing effect is better. And this can realize end-to-end connection, avoid power loss and improve drilling efficiency.

3. Concentricity
Self-drilling anchor system is anchoring while drilling. If the thread concentricity at both ends of coupler is too low, hollow bar will swing during drilling, which will affect the drilling efficiency and quality. The coupler's raw materials are specially designed to make its strength and precision higher, which can effectively improve the matching accuracy of hollow bar and coupler.

Due to the limited length of self-drilling anchor bolt, the coupler is essential in the construction, so the choice of a more appropriate coupler can make the project safer. 

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