Pipe Pig Cleaning with Pivoting Teeth for Hard Deposit Removal
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Solution Overview
Problem
Existing methods for cleaning piping in alumina extraction systems, such as high-pressure jet washing and acid passing, are inefficient and pose safety risks, especially when dealing with hard deposits like quartz and iron titanate.
Innovation Solution
A pipe cleaning device with a propelling piston and multiple cleaning tools, each equipped with pivotable arms and interchangeable inserts with teeth, is used to gradually remove encrustations by a combination of scraping and percussive action, allowing for controlled retention of a protective layer of deposits on the pipe surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-pressure jet washing is used to remove hard deposits, then cleaning effectiveness is improved, but operator safety deteriorates and equipment integrity is compromised
Solution Approach 1:
The patent replaces the high-pressure water jet mechanical cleaning system with a mechanically driven pigging system. The pig device is propelled by pressure differential (not high-pressure jets) and uses mechanical cutting elements (rotating cutters, scraping surfaces) to remove deposits. This substitution eliminates the safety hazards of high-pressure jet washing while maintaining cleaning effectiveness through controlled mechanical action.
Solution Approach 2:
The pig device acts as an intermediary tool that performs the cleaning function without requiring direct operator exposure to hazardous conditions. The pig is propelled through the pipe by pressure differential and performs the cleaning action remotely, mediating between the cleaning objective and the safety constraint by isolating operators from the actual cleaning mechanism.
2Manufacturing precision
If high-pressure jet washing is used to remove all deposits, then pipe diameter is restored, but cleaning time increases and safety risks worsen
Solution Approach 1:
The patent applies partial action by not requiring complete removal of all deposits. The pig device is designed to remove sufficient encrustations to restore adequate pipe diameter and flow characteristics, accepting that some residual deposit may remain. This partial removal approach significantly reduces cleaning time compared to complete removal while still achieving the functional objective of maintaining pipe performance.
Solution Approach 2:
The patent changes the operational parameters from high-pressure intermittent jet washing to controlled-pressure continuous pig propulsion. By maintaining a steady pressure differential (e.g., 5-20 bar) throughout the pigging operation, the system achieves consistent cleaning progress without the time losses associated with setup, operation, and teardown of high-pressure jet washing equipment.
3Productivity
If conventional cutting wheels are used to remove encrustations, then deposit removal is achieved, but the cutting mechanism is insufficiently robust for hard deposits
Solution Approach 1:
The patent employs composite cutting mechanisms that combine multiple materials and approaches. The pig device incorporates rotating cutters made from hard, wear-resistant materials (such as carbide or hardened steel) combined with scraping surfaces. This composite approach provides the robustness needed to handle hard deposits like quartz and iron titanate that conventional cutting wheels cannot effectively remove.
Solution Approach 2:
The patent transitions from static cutting wheels to dynamically rotating cutters driven by the pig's movement through the pipe. The rotating motion, generated by the pressure differential propelling the pig, provides continuous cutting action that is more effective and robust than stationary or slowly rotating conventional cutters. The dynamic rotation allows the cutting edges to maintain optimal contact with the pipe wall and effectively fracture hard deposits.
4Manufacturing precision
If prolonged acid passing and jet washing are used to ensure sufficient pipe diameter, then cleaning thoroughness is improved, but process time increases and safety risks worsen
Solution Approach 1:
The patent replaces the prolonged chemical (acid) and high-pressure mechanical (jet washing) cleaning processes with a single-pass or multi-pass pigging operation. The pig device mechanically removes deposits through controlled pressure propulsion and integrated cutting/scraping mechanisms, achieving sufficient pipe diameter restoration in a fraction of the time required for prolonged acid passing and jet washing sequences.
Solution Approach 2:
The patent implements continuous useful action by maintaining steady pressure differential throughout the pigging operation. The pig propels continuously through the pipe length, performing cleaning work throughout its entire travel. This continuous action eliminates the intermittent nature of jet washing (setup, operation, teardown cycles) and acid passing (pumping, soaking, flushing stages), significantly reducing total process time while maintaining cleaning effectiveness.
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 pipe cleaning device effectively reduces the thickness of encrustations to a desired level, maintaining pipe diameter and preventing corrosion, while being safer and more efficient than traditional methods, allowing for simultaneous cleaning of multiple pipes.
Implementation Method 1
fluid is forced into the pipe (5) to drive the pipe cleaning device (1) along the pipe (5)
Implementation Method 2
Each cleaning tool (100) comprises a plurality of circumferentially-spaced arms (200)... The working surfaces of the arms (200) are arranged to engage encrustations on the inner surface of the pipe (5)
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The disclosure relates to an apparatus for cleaning piping and a method of cleaning piping. In particular, the apparatus may be a "pig", a device for insertion into a pipe for removing deposits from the inner surface of the pipe. The disclosure is particularly applicable in the field of alumina production. In this field, it is common to obtain alumina from bauxite by grinding the bauxite, mixing this with caustic liquor to form a slurry, and heating the slurry. This leads to the alumina trapped in the bauxite dissolving to form a supersaturated solution of alumina in the caustic liquor with a suspension of the residue from the bauxite. Using known methods, alumina can be recovered from such a solution. The disclosure provides a pipe cleaning device (1) for removing deposits from the inner surface of a pipe. The pipe cleaning device (1) comprises a propelling piston (10) and a cleaning tool (100) attached to the propelling piston (10), wherein: the cleaning tool (100) comprises a main body (110) and a plurality of circumferentially spaced arms (200), pivotably attached to the main body (110) and urged by an urging force to pivot away from a longitudinal axis of the main body (110); each arm (200) has an insert (300) with a plurality of teeth (400) on its distal end defining a working surface for engaging deposits on the inner surface of the pipe; and the teeth (400) have a distal end and a cutting edge spaced from the distal end.