Asymmetrical Chute for Centrifugal Spreader Flow Compensation
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Solution Overview
Problem
Centrifugal spreaders face challenges in precisely controlling the spreading pattern due to the 'flow effect,' where variations in particle dose significantly alter the shape and direction of the spreading layer, requiring complex servo-control systems and introducing reliability risks.
Innovation Solution
The chute's outlet section is designed with asymmetrical walls, causing the barycenter of the particle flow to shift transversely, resulting in an angular displacement of the average feed point relative to the spinning disc, allowing for flow rate adjustments without moving the chute, thus maintaining a constant spreading pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the quantity of particles delivered onto the disk is varied to adjust the dose, then the spreading requirements are met, but the shape and direction of the spreading layer varies significantly
Solution Approach 1:
The chute is designed with an asymmetrical cross-section where one lateral wall is inclined at an angle different from the other lateral wall. This asymmetry causes the flow of particles to shift laterally as the dose varies, automatically compensating for the flow effect and maintaining a constant spreading pattern shape regardless of the quantity of particles delivered.
2Measurement precision
If servo-control systems are used to maintain constant spreading pattern, then the spreading precision is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The asymmetrical chute design enables the system to automatically compensate for flow effect variations without requiring external control systems. The geometric configuration itself performs the compensation function, making the system self-regulating and eliminating the need for servo-motors, sensors, and control electronics.
Solution Approach 2:
The invention extracts and eliminates the complex servo-control system from the spreading apparatus, replacing it with a simple asymmetrical geometric configuration. This removes the disturbing complexity while retaining the essential function of maintaining constant spreading pattern.
3Stability of the object's composition
If the chute position is moved angularly to compensate for flow effect, then the spreading pattern stability is improved, but the reliability decreases due to additional moving parts
Solution Approach 1:
The asymmetrical cross-section of the chute creates a lateral shift in particle flow that compensates for flow effect. This geometric solution provides spreading pattern stability without any moving parts, thereby maintaining high system reliability.
Solution Approach 2:
The chute cross-section is segmented into two lateral walls with different inclination angles, creating asymmetry that produces the desired flow compensation effect while keeping the overall structure static and reliable.
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
This approach simplifies the control of the spreading pattern, eliminating the need for servo-control systems and reducing maintenance, while maintaining a consistent web shape and dimensions across varying flow rates.
Implementation Method 1
One of the known difficulties of spreading is the problem of the 'flow effect' (sometimes also called, by abuse of language, 'dose effect'). Indeed, it can be seen that, depending on the quantity of particles delivered, the resulting crescent varies greatly, in area and in direction
Implementation Method 2
They implement one or more mobile disks in rotation, and equipped with blades. The product to be spread can in particular be stored in a hopper, and brought or dumped above each disk by a chute, so as to be projected via the blades onto the ground on which it is to be deposited.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A
AI summary
The device has a trough (20) whose two side walls and base wall are formed such that a section of an outlet end of the trough causes displacement of baric center positions (B1, B2) of a particle flow section at the level of the end in a direction (51) opposite a rotation direction (28) of a spreader disk (24), when quantity of particles in the trough increases from one level (N1) to another level (N2). The side walls are not symmetric with respect to a plane perpendicular to the base wall, and form respective angles ranging between 50 and 75 degree and 110 and 130 degree, with the base wall.