Piston-Check Valve Priming in Fluid Sprayer Pumps

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Solution Overview

Problem

Fluid sprayer pumps often require manual priming to overcome air pressure and stuck check valves, which can be inefficient and require additional components to dislodge sticky residues, hindering the initial fluid uptake.

Innovation Solution

The pump design includes a piston that impacts and displaces the valve member during a priming stroke, building fluid pressure to drive the valve from a closed to an open position, eliminating the need for manual intervention and additional components by using a gear-driven wobble plate to convert rotational motion into linear piston movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the check valve is designed to remain closed during normal operation to maintain fluid pressure, then fluid containment is improved, but the valve becomes stuck in the closed position during priming due to air pressure and sticky residues

Engineering Contradiction:
Improvefluid containmentVSAvoidvalve opening during priming
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The piston is designed to perform a preliminary action during priming by directly impacting the check valve to knock it open before fluid pressure can build. This preliminary mechanical action overcomes the stuck condition caused by sticky residues and air pressure, allowing the valve to open for priming without compromising its normal closed position for fluid containment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transitions from a static valve position to a dynamic opening mechanism. The piston's reciprocating motion creates a dynamic impact force that temporarily overcomes the static sealing force holding the check valve closed, enabling the valve to switch between stable closed state (for containment) and temporary open state (for priming)

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If manual intervention is required to dislodge the check valve during priming, then the valve can be opened, but the device complexity increases and user convenience deteriorates

Engineering Contradiction:
Improvevalve openingVSAvoidpriming mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The priming system performs self-service by using the piston's own reciprocating motion to automatically knock the check valve open during priming operations. The piston directly impacts the valve without requiring external manual tools or additional disassembly steps, making the system self-sufficient for the priming function

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The priming function is merged with the existing piston-driven pumping mechanism. The same piston that drives fluid during operation is also used to knock the check valve open during priming, combining two functions (pumping and priming) into a single integrated system without adding separate priming components

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If additional components are added to dislodge the check valve, then the valve can be opened during priming, but the device complexity and number of parts increase

Engineering Contradiction:
Improvevalve openingVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The piston serves multiple functions: it drives fluid during normal pumping operations and simultaneously acts as a priming tool by knocking the check valve open. This multi-functionality eliminates the need for separate dislodging components, achieving valve opening capability without increasing the number of parts

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the priming function from the set of required components by using the existing piston's mechanical impact capability. Instead of adding a separate dislodging mechanism, the solution takes out the priming requirement and fulfills it through the piston's inherent reciprocating motion, reducing the need for additional components

Inventive Principle:
Principle #2Taking out (Extraction)

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 design facilitates quicker and more efficient priming by automatically knocking the valve member open, reducing wear and simplifying the process, ensuring effective fluid uptake without manual disassembly and reassembly, thus enhancing the overall spraying efficiency.

Implementation Method 1

The downstream end of the piston is configured to impact the valve member to dislodge a check valve stuck in a closed position

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 2

The first piston is configured to build a fluid pressure between the downstream end of the first piston and the first valve member during the pressure stroke

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 3

a spring disposed within the cage and configured to urge the ball towards the closed position

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 4

the downstream face of the first cylinder includes a sealing lip configured to mate with a curvature of the ball such that a portion of the ball extends into the cylinder

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP3296021B1Piston-valve engagement in fluid sprayers
Publication Date: 2021.04.07 GRACO MINNESTOA INC
  • EP3296021B1 patent drawingFigure 1A
  • EP3296021B1 patent drawingFigure 1B
  • EP3296021B1 patent drawingFigure 2A

AI summary

A pump (20) draws fluid from a reservoir and drives the fluid downstream to a spray tip where the fluid is applied to a surface. A piston (30) is driven in a reciprocating manner to pump the fluid. A check valve (32) is disposed downstream of the piston (30) to regulate a flow of the fluid downstream from the piston (30). The pump (20) is initially dry and is primed with fluid prior to operation. To facilitate priming, the piston (30) is dimensioned to impact the ball (56a) and unseat a valve member (56) of the check valve during a priming stroke, thereby ejecting any air from the pump (20) through the check valve (32). With the air ejected from the pump (20), a vacuum is formed during a suction stroke of the piston (30), which draws fluid downstream from the reservoir to prime the pump (20).