Mill Liner Bolt With Sealing Member
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mill liner bolts in rotating ore mills experience premature wear and failure due to persistent flow of grinding fluids, point loads, and misalignment, leading to loosening and subsequent costly downtime and repairs.
Innovation Solution
A mill liner bolt design featuring a bolt shank with an oblong head and tapered load-bearing surfaces, along with a compressible sealing member positioned to shift contact area higher on the tapered sidewalls, forming a partially elastic joint that prevents fluid flow and reduces the risk of break-out, while maintaining clamp loading during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mill liner bolts are installed with standard clearance holes and tapered load-bearing surfaces, then the bolts can be easily installed and removed, but point loads are created due to clearance and tolerances causing early embedment and loss of clamp load
Solution Approach 1:
The patent applies local quality by providing a localized bearing surface enhancement on the bolt head. Specifically, a raised ring or annular shoulder is created on the bolt head that contacts the liner bore surface, concentrating the load-bearing function in a specific location that is optimized for both load distribution and liner engagement, while the rest of the bolt head maintains its tapered shape for proper alignment.
Solution Approach 2:
The patent applies preliminary action by pre-forming a bearing surface on the bolt head during manufacturing. The raised ring or annular shoulder is created in advance during bolt fabrication, ensuring that when the bolt is installed, the load-bearing surface is already optimized and positioned correctly, eliminating the need for field adjustments or modifications to achieve proper load distribution.
2Reliability
If mill liner bolts are tightened to maintain clamp load, then the liner remains securely attached, but the grinding fluids can still flow through the bores causing surface racing and premature wear
Solution Approach 1:
The patent applies the intermediary principle by introducing a sealing element as a mediator between the bolt head and the liner bore. This sealing element, such as an O-ring or gasket, fills the clearance between the bolt head and bore surface, preventing grinding fluid from passing through while still allowing the bolt to maintain its clamping function. The seal acts as an intermediate component that addresses the harmful fluid flow without compromising the mechanical attachment.
3Ease of manufacture
If the bolt head contact area is positioned lower in the bore, then the installation is simpler, but the point loads cause premature failure and pull-through of the liner
Solution Approach 1:
The patent applies the dimensionality change principle by modifying the bolt head geometry to include a raised ring or annular shoulder that extends axially upward from the tapered surface. This creates an additional dimensional feature that shifts the load-bearing contact area to a higher position in the bore, where the liner material is thicker and better able to withstand the concentrated loads without pulling through.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents surface racing, maintains bolt clamping force, and reduces the risk of bolt pull-through and loosening, leading to prolonged equipment life and reduced maintenance costs by creating a high-pressure seal and distributing load forces more evenly.
Implementation Method 1
Compression of the seal material further serves to provide a partially elastic joint
Implementation Method 2
Compression of the seal material further serves to provide a partially elastic joint
Implementation Method 3
The mill liner bolts are loaded by tightening of a nut threaded onto the mill liner bolt shank threads
Data Source
AI summary
A forged, mill liner bolt (100) has a head (114), a shank (112), tapered load-bearing surfaces (116) and lateral projections (120) defining an undercut surface (117), and a sealing member (118) abutting the undercut surface. A plurality of plastically deformable projections (122) extend from the tapered load-bearing surfaces (116) for spreading a load applied to the bolt. Sealing member (118) provides a partially-elastic joint to maintain clamp loading. Sealing member (118) provides an interior seal within a bore in a mill liner to prevent leaking of and racing by mill slurry liquids.