Air Spring Pneumatic Rejection System
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Solution Overview
Problem
Existing electronically-controlled sorting machines for the fruit and vegetable industry face inefficiencies in product rejection due to inconsistent response times, high costs, limited force generation, slow ejector speeds, and potential damage to rejected products, primarily attributed to the limitations of mass-produced 4-way valves and conventional pneumatic components.
Innovation Solution
A double-acting cylinder and piston mechanism with a novel pneumatic arrangement, including a high and low pressure manifold, a control valve, and a pivotally mounted paddle, allows for adjustable ejector forces and quick exhaust venting to achieve higher speeds, improved repeatability, and reduced product damage, using 3/2 way valves instead of 4-way valves for cost savings and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mass-produced 4-way valves and conventional pneumatic components are used, then device complexity is reduced and ease of manufacture is improved, but response time consistency deteriorates and ejector speed is limited
Solution Approach 1:
The pneumatic system is segmented into multiple independent circuits, each with its own quick-exhaust valve and pressure regulation. This segmentation allows each ejector to operate independently with optimized response characteristics, improving consistency while maintaining ease of manufacture through modular assembly
Solution Approach 2:
The system dynamically adjusts pressure levels and flow rates for each ejector based on real-time requirements. Quick-exhaust valves provide dynamic pressure release, and the system adapts firing sequences to optimize response time consistency across all ejectors while using standard components
2Device complexity
If conventional 4-way valves are used, then device complexity is minimized, but ejector speed and force generation are limited
Solution Approach 1:
The exhaust function is extracted from the main 4-way valve and implemented as separate quick-exhaust valves for each ejector circuit. This extraction enables independent and rapid pressure release, dramatically increasing ejector speed while keeping the main control valve simple
Solution Approach 2:
Air springs are pre-charged to optimal pressure levels before ejector activation. This preliminary pressurization ensures that when the ejector fires, maximum force and speed are achieved immediately, bypassing the slow pressure build-up limitation of conventional valves
3Ease of manufacture
If conventional pneumatic components are used, then cost is reduced, but force generation capability and product damage control are limited
Solution Approach 1:
Each ejector circuit is equipped with local pressure regulation and air spring pre-charging, providing tailored force characteristics for each position. This local optimization enables precise force control to prevent product damage while using cost-effective standard components
Solution Approach 2:
Air springs are pre-charged to act as cushioning elements that absorb excess force and provide controlled deceleration. This beforehand cushioning prevents product damage by softening the impact at the end of each ejector stroke while maintaining high force during the power stroke
4Device complexity
If conventional 4-way valves are used, then device simplicity is maintained, but compressed air consumption and cycle time are increased
Solution Approach 1:
Quick-exhaust valves enable the system to rush through the exhaust phase by providing direct, unrestricted pressure release to atmosphere. This skipping of the gradual pressure equalization process dramatically reduces cycle time while maintaining simple valve architecture
Solution Approach 2:
The system uses periodic pre-charging of air springs followed by rapid discharge cycles. This rhythmic pattern of pre-charge and fire optimizes compressed air consumption by ensuring each ejector is ready to fire immediately, reducing waiting time and improving 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 solution enables higher ejector speeds, consistent response times, reduced shock loading, and minimal product damage, while reducing compressed air consumption and operational costs, with improved sorting accuracy and longer system lifespan.
Implementation Method 1
a second air spring cushion in said second region for cushioning an impact between the piston and the front end wall of the cylinder
Implementation Method 2
a first air spring cushion in said first region for cushioning an impact between the piston and the rear end wall of the cylinder
Data Source
AI summary
A double-acting cylinder and piston mechanism comprising a cylinder (1) substantially closed at both ends by front (5) and rear (7) end walls, a piston (8) axially displaceable within the cylinder (1), a first region (6) defined between the piston (8) and the rear end wall (7) of the cylinder (1) and a second region (4) defined between the piston (8) and the front end wall (5) of the cylinder (1), a piston rod (2) extending from the piston (8) through the front end wall (5) of the cylinder (1), an air inlet port (19) for communication with said first region (6) of the cylinder (1) and at least one exhaust vent (14) which is exposed during axial displacement of the piston (8) for release of air delivered to the cylinder (1) through the air inlet port (19). The double-acting cylinder and piston mechanism is suitable for use in a pneumatic product rejection system, the piston (8) being connected to an ejector finger (18) for displacement of the finger (18) between a clear position and at least one product rejecting disposition of the finger (18).