Backpack Sprayer Internal Double Action Pump
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Solution Overview
Problem
Manually actuated backpack sprayers with external pumps are prone to impact damage, contamination, and inefficiency due to complex plumbing and high handle force requirements, leading to user fatigue and limited operating pressures.
Innovation Solution
A backpack sprayer system with an internal double action pump unit, comprising a cylinder and piston assembly, and check valve system that pressurizes fluid on both up-stroke and down-stroke, reducing the size and force needed to operate the pump while maintaining efficient fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an external pump unit is used in manually actuated backpack sprayers, then the pump is protected from contamination, but the pump becomes susceptible to impact damage and requires complex plumbing
Solution Approach 1:
The pump unit is merged with the tank body to form an integrated internal pump system. The pump housing is formed within the tank structure, eliminating the need for external pump mounting and complex external plumbing connections. This integration reduces the number of external connections and potential leak points while protecting the pump from impact damage.
2Device complexity
If an internal pump unit is used in backpack sprayers, then plumbing is simplified, but the pump becomes susceptible to impact damage and contamination
Solution Approach 1:
The pump unit is positioned within the tank structure in a location that provides inherent protection from impact damage. The tank body acts as a protective housing, cushioning the pump against external impacts and preventing contamination from dust and dirt, thereby resolving the susceptibility to harmful factors while maintaining simplified internal plumbing.
3Device complexity
If a single action piston pump is used, then the pump structure is simple, but the pump requires large piston and cylinder size to move useful liquid per stroke
Solution Approach 1:
The pump system employs a double action piston mechanism where fluid is pressurized during both the up-stroke and down-stroke of the piston. This continuous useful action allows a smaller piston and cylinder to move the same amount of liquid per stroke cycle compared to a single action pump, reducing the volume of moving parts while maintaining pumping efficiency.
4Productivity
If a large piston and cylinder are used to move useful liquid per stroke, then more liquid is delivered per stroke, but the handle force required increases leading to user fatigue
Solution Approach 1:
By implementing double action pumping where both the up-stroke and down-stroke contribute to fluid pressurization and delivery, the system achieves high liquid delivery per stroke cycle with a smaller piston area. This continuity of useful action reduces the force required on the handle while maintaining productive liquid transfer, thereby reducing user fatigue.
5Productivity
If a large piston and cylinder are used, then more liquid is moved per stroke, but the maximum operating fluid pressure decreases
Solution Approach 1:
The double action pump design allows both strokes to contribute to pressurizing the fluid in the pressure vessel. This continuous pressurization during up-stroke and down-stroke enables the system to achieve both adequate liquid delivery per stroke cycle and high maximum operating fluid pressures, resolving the trade-off between productivity and pressure capability.
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 double action pump system reduces user fatigue by requiring less handle force and increases operating fluid pressures, allowing for easier plumbing and cleaning, and providing a more efficient fluid delivery mechanism.
Implementation Method 1
an inlet check valve assembly and an outlet check valve assembly. The inlet check valve assembly is configured to direct fluid flow from the spray tank into the pump cylinder during both up-stroke and down-stroke of the piston
Implementation Method 2
A first pressure chamber is defined within the inner cylinder wall between the bottom wall of the cylinder housing and the piston... Pressurized fluid within the second pressure chamber is discharged from the outlet tube to the second tank
Data Source
AI summary
An internal pump backpack sprayer system includes first and second tanks and a double action pump unit. The first tank defines an open volume to hold a fluid. The second tank is received within the first tank and receives a pressurized fluid therein. The double action pump includes a cylinder and piston assembly having a cylinder housing with first and second inlets and first and second outlets. A piston is located and moveable within a cylinder. When the piston moves in an up-stroke, a first portion of the fluid is drawn from the first tank through the first inlet while the pressurized fluid is discharged to the second tank through the second outlet. When the piston moves in a down-stroke, a second portion of the fluid is drawn from the first tank through the second inlet while the pressurized fluid is discharged to the second tank through the first outlet.