Variable-Speed Knapsack Sprayer for Flow and Pressure Control
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Solution Overview
Problem
Existing knapsack sprayers face issues with jamming, liquid leakage, and the need for adjusting spray flow rates and types, particularly when dealing with different liquids of varying viscosities, and require improved control over spraying at different distances and for high places.
Innovation Solution
A knapsack sprayer equipped with a battery-powered electric motor and pump system, featuring a first operating member to start or stop the motor and adjust its speed, a second operating member to control a valve, and a control device to synchronize both, allowing precise control over liquid flow and spray direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the user manually adjusts spray flow rate and operates valves for different liquids, then the sprayer can handle different usage scenarios, but the operation becomes complex and inconvenient
Solution Approach 1:
The patent replaces manual mechanical operation with an electric motor-driven pump system. The motor automatically controls liquid flow rate by adjusting its rotational speed, eliminating the need for manual valve adjustments. Different liquids (water, fertilizer, pesticides) are handled by simply changing the liquid in the tank while the motor adapts its speed, converting complex mechanical adjustments into simple electrical control
Solution Approach 2:
The patent changes the operating parameter from fixed mechanical valve positions to variable motor rotational speed. The motor speed can be continuously adjusted to match different liquid viscosities and spray requirements, providing adaptability without increasing operational complexity. The system monitors and adjusts speed parameters dynamically based on load conditions
2Adaptability or versatility
If the sprayer uses fixed spray pressure, then the structure is simple, but it cannot spray viscous liquids or reach high places and distant plants
Solution Approach 1:
The patent transforms the fixed-pressure system into a dynamic pressure system by using a motor-driven pump with variable speed control. The pump pressure automatically adjusts according to motor speed, enabling the system to adapt to different liquid viscosities and spray distances. High viscosity liquids require lower speeds, while distant or high-place spraying requires higher speeds, all controlled dynamically without complex mechanical pressure regulation mechanisms
Solution Approach 2:
The patent replaces complex mechanical pressure regulation mechanisms with electrical motor control. Instead of using multiple valves, regulators, and mechanical linkages to control pressure, the system uses electronic speed control of the motor to achieve the same effect, simplifying the overall device structure while increasing adaptability
3Ease of operation
If the sprayer starts and stops frequently, then it responds to user needs, but jamming and liquid leakage occur
Solution Approach 1:
The patent incorporates feedback control through the motor controller that monitors operational parameters and adjusts accordingly. Before starting, the system checks liquid levels and system state. During operation, it monitors motor current and pump performance to prevent conditions that lead to jamming. The feedback mechanism ensures smooth start-up and shutdown sequences, preventing liquid leakage by maintaining proper pressure throughout the cycle
Solution Approach 2:
The patent performs preliminary checks and preparations before actual spraying operations. The system pre-checks liquid levels, pump readiness, and nozzle conditions before initiating spray. During shutdown, it maintains pressure for a brief period to ensure complete liquid discharge from the pump, preventing leakage. These preliminary actions prevent jamming and leakage before they can occur
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
Enables convenient, efficient, and safe operation with adjustable spray rates and distances, reducing jamming and leakage, and facilitating the use of different liquids without manual adjustments, enhancing user experience and operational efficiency.
Implementation Method 1
an electric motor and a pump, where the electric motor drives the pump to draw the liquid from the liquid reservoir
Implementation Method 2
the electric motor drives the pump to suck liquid from the liquid source into the machine and pressurize the liquid
Implementation Method 3
The pressurized liquid is further pumped to the nozzle and dispersed into small droplets to be sprayed out
Data Source
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AI summary
A knapsack sprayer includes a liquid reservoir configured to store liquid; a nozzle configured to spray the liquid; an operating device connected to the liquid reservoir and the nozzle and configured to be held by a user to control the spraying direction of the nozzle; and a power unit powered by a battery pack and including an electric motor and a pump, where the electric motor drives the pump to draw the liquid from the liquid reservoir. The operating device is provided with a first operating member for allowing the electric motor to start or prohibiting the electric motor from starting, and the first operating member is configured to be operated by the user to adjust the rotational speed of the electric motor.