Cylindrical Tank Inner Surface Grinding via Sliding Abrasive Motion
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Solution Overview
Problem
Current methods for grinding and cleaning cylindrical tanks, particularly in the pharmaceutical and chemical industries, face challenges in achieving a smooth, contamination-free surface due to limitations in existing grinding and cleaning technologies, which can lead to residual dirt and safety concerns.
Innovation Solution
A method and assembly for grinding the inner surface of cylindrical tanks involving a frame that holds the tank securely for rotation around a central axis, using a grinding material that moves in a sliding motion to prevent tumbling, combined with a cleaning system comprising trolleys for efficient fluid delivery and monitoring, ensuring thorough surface polishing and cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tank is rotated at high speed during grinding, then the grinding material tumbles and covers more surface area, but the surface roughness increases and the grinding precision deteriorates
Solution Approach 1:
The patent applies dynamic control by rotating the tank at variable speeds - initially at higher speeds to distribute grinding material and cover surface area, then reducing to lower speeds (1-30 rpm) during the final grinding stage to prevent tumbling and achieve the required surface roughness of Ra ≤ 0.2 μm. This dynamic speed adjustment resolves the contradiction between productivity and precision.
2Manufacturing precision
If the tank remains in a fixed horizontal position during grinding, then the grinding material stays at the bottom and grinds only a limited area, but changing the position requires complex positioning mechanisms
Solution Approach 1:
The patent uses dynamic position changes by tilting the tank to different angles (0°, 45°, 90°) during the grinding process. This allows the grinding material to redistribute and contact different areas of the inner surface. The tilting mechanism is relatively simple compared to complex positioning systems, as it leverages gravity to move the grinding material naturally.
Solution Approach 2:
The grinding process employs periodic action by alternating between different tank positions (horizontal, tilted at 45°, vertical at 90°) and rotating the tank at different speeds during each position. This periodic variation ensures comprehensive surface coverage while using simple, repeatable operations rather than complex continuous positioning.
3Productivity
If conventional cleaning methods are used after grinding, then the cleaning process is simple and quick, but residual dirt and contamination remain on the surface
Solution Approach 1:
The patent replaces conventional mechanical cleaning methods with a chemical cleaning system using an automated cleaning machine that circulates cleaning solution through the tank. This chemical cleaning process, combined with UV irradiation, thoroughly removes residual dirt and contaminants from the ground surface, ensuring the high cleanliness required for pharmaceutical applications while maintaining efficient throughput.
Solution Approach 2:
The cleaning process uses strong oxidizing agents in the cleaning solution to chemically break down and remove organic contaminants and residual grinding material from the tank surface. This oxidation-based cleaning is more effective than mechanical methods alone, ensuring complete removal of contaminants while the automated system maintains cleaning speed and productivity.
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 method effectively reduces surface roughness to less than 0.2 micrometers and ensures thorough cleaning, minimizing contamination risks and enhancing safety by using a controlled grinding and cleaning process.
Implementation Method 1
causing the grinding material to move in a sliding and non-tumbling movement relative to the inner surface
Implementation Method 2
rotating the cylindrical tank about the central axis by using the motor and the drive mechanism at a rotational speed of less than 100rpm
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Apparatus and method of grinding an inner surface of a tank (12) the tankc consisting of a convex first part (12b), a convex second part (12c) and a cylindrical part (12a) by providing a a frame (14) for holding the tank (12) and a stand (16) rotably connected to the frame (14). Initially, the frame assumes a horizontal position and an amount of grinding material (28) is placed into the tank covering a part of the inner surface of the tank between the parts. Thereafter the cylindrical tank is rotated about the central axis causing the grinding material to move in a sliding and non-tumbling movement relative to the inner surface. The last step is repeated in a first tilted position and in a second tilted position wherein the grinding material extends on the inner surface between the cylindrical part and the respective points of interception between the parts and the central axis of the tank.