Tank Cleaning Nozzle Control for Helical Spray Coverage
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Solution Overview
Problem
Existing tank cleaning apparatuses suffer from inefficiencies, such as cleaning fluid covering previously cleaned areas due to diagonal impingement track portions and pressure wave generation during fluid flow interruptions.
Innovation Solution
A control system that alternately rotates the nozzle about a second axis by a predefined cleaning angle, with varying angular velocities, allowing continuous fluid application and helical impingement trajectories, preventing fluid coverage of previously cleaned areas and minimizing pressure waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the nozzle rotates continuously about the second axis during cleaning, then the cleaning coverage is increased, but the cleaning fluid may cover previously cleaned areas causing re-contamination
Solution Approach 1:
The nozzle rotation is implemented as a periodic reciprocating motion rather than continuous rotation. The nozzle alternates between rotating in the cleaning direction (first rotation direction) and returning to its initial position (second rotation direction), creating periodic cleaning passes that prevent fluid from covering previously cleaned areas while maintaining comprehensive coverage over time
Solution Approach 2:
Instead of continuous unidirectional rotation, the system inverts the approach by implementing bidirectional reciprocating rotation. The nozzle rotates forward to clean a section, then reverses direction to return to the starting position, creating an oscillating motion pattern that ensures each cleaned area remains clean while progressively covering the entire tank surface
2Reliability
If the nozzle rotates slowly about the second axis to improve cleaning quality, then the cleaning precision is improved, but the cleaning time increases
Solution Approach 1:
The cleaning process is divided into periodic cycles of forward rotation (cleaning phase) and backward rotation (return phase). During the forward phase, the nozzle rotates slowly to ensure high-quality cleaning, while the backward phase quickly returns the nozzle to its initial position, thereby reducing the overall time loss while maintaining cleaning quality during the productive phase
Solution Approach 2:
The system skips the return journey by rotating the nozzle quickly in the second rotation direction back to the initial position after completing the cleaning pass. This rushing through of the non-productive return phase minimizes time loss while allowing the nozzle to maintain slow, high-quality rotation during the forward cleaning phase
3Productivity
If the nozzle rotates quickly about the second axis to reduce cleaning time, then the productivity is improved, but the cleaning quality deteriorates
Solution Approach 1:
The system alternates between slow rotation during the forward cleaning pass (maintaining quality) and fast rotation during the backward return pass (improving speed). This periodic variation in rotation speed ensures that high-quality cleaning is performed during the productive phase while minimizing time loss during the non-productive return phase
Solution Approach 2:
The nozzle rotation speed is made dynamic rather than constant, varying between slow and fast speeds depending on the phase of operation. The control system adjusts the rotation velocity in real-time, maintaining slow speed during the forward cleaning motion for quality and fast speed during the backward return motion for efficiency
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
Ensures thorough tank cleaning without fluid re-contamination and pressure wave issues, maintaining continuous fluid supply and optimizing impingement patterns for efficient cleaning.
Implementation Method 1
allowing continuous fluid application and helical impingement trajectories
Implementation Method 2
minimizing pressure waves
Data Source
Figure 1
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AI summary
An apparatus (2) for cleaning the inner side of a tank (1) comprises a frame (3) which is mounted or mountable to a tank (1), a nozzle support (5) which is rotatably mounted to the frame (3) and drivable with respect to the frame (3) about a first axis of rotation (6), a nozzle (4) which is rotatably mounted to the nozzle support (5) and drivable with respect to the nozzle support (5) about a second axis of rotation (7) extending transversely to the first axis of rotation (6). The nozzle (4) has a spraying direction facing away from the second axis (7). The apparatus also comprises a control system (8, 9, 11-30) for driving the nozzle support (5) and the nozzle (4), which is configured such that under operating conditions the nozzle (4) is rotated about the second axis (7) alternatingly from a cleaning start position to a cleaning stop position by a predefined cleaning angle (CA) and from the cleaning stop position to the cleaning start position, which cleaning angle (CA) is smaller than one revolution. The angular velocity of the nozzle (4) with respect to the nozzle support (5) is smaller than the angular velocity of the nozzle support (5) with respect to the frame (3) within the cleaning angle (CA) and smaller than the angular velocity of the nozzle (4) with respect to the nozzle support (5) during the movement from the cleaning stop position to the cleaning start position.