Piston-Check Valve Priming for Dry Fluid Sprayer Pumps

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Solution Overview

Problem

Fluid sprayer pumps often require manual priming to remove air trapped between check valves and pistons, which can be hindered by surface tension or sticky residues, leading to inefficient startup and additional user intervention.

Innovation Solution

The design incorporates a piston that impacts and unseats the check valve ball during the priming stroke, creating a flow path for air to exit and establishing a vacuum for fluid intake, eliminating the need for manual intervention and ensuring quicker priming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pump is operated without manual priming intervention, then automation and ease of operation improve, but air trapped in the cylinder prevents proper fluid uptake and the check valve remains stuck closed

Engineering Contradiction:
Improveease of startupVSAvoidfluid uptake reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The piston is designed to automatically unseat the check valve ball during its reciprocating motion without requiring user intervention. The piston's downstream end impacts the ball to open the valve during the suction stroke, enabling the pump to self-prime and eliminating manual priming operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The piston performs a preliminary action by impacting the check valve ball during the first few strokes to unseat it before normal pumping operation begins. This preliminary unseating action ensures that the check valve is properly opened to allow fluid intake before the pump enters its normal cycling mode.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the check valve is kept closed to maintain sealing, then sealing reliability improves, but air compression becomes insufficient to overcome surface tension and sticky residue

Engineering Contradiction:
Improvecheck valve sealingVSAvoidpriming speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The check valve transitions from a static closed position to a dynamic open position through piston impact. The valve ball is designed to be movable between seated and unseated positions, allowing it to dynamically respond to piston motion and pressure changes during the priming process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The piston applies periodic impact forces to the check valve ball during its reciprocating motion. This periodic action gradually unseats the ball over multiple strokes, overcoming the adhesive forces of sticky residue and surface tension through repeated mechanical impact rather than continuous force.

Inventive Principle:
Principle #19Periodic action

3Productivity

If manual priming procedures are implemented, then air removal effectiveness improves, but device complexity and user effort increase

Engineering Contradiction:
Improvepriming effectivenessVSAvoidpriming mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The piston serves multiple functions: it acts as both the pumping element and the priming mechanism. By designing the piston with a downstream end that impacts the check valve ball, the same component performs both fluid displacement and valve unseating, eliminating the need for separate priming devices or mechanisms.

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

Solution Approach 2:

The priming function is merged with the normal pumping operation. The piston's reciprocating motion that drives fluid transfer also simultaneously unseats the check valve, combining two previously separate functions (priming and pumping) into a single integrated mechanism.

Inventive Principle:
Principle #5Merging (Combining)

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 solution automates the priming process, reducing user effort and simplifying the startup of fluid sprayers by ensuring efficient fluid uptake and dispensing, while minimizing wear on components and eliminating additional components for manual priming.

Implementation Method 1

The piston can compress the air, but the air pressure can be insufficient to overcome the force maintaining the check valve in the closed position

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a vacuum can form between the piston and the check valve during the suction stroke. When the downstream end of the piston passes an intake, the vacuum draws pumped fluid into the chamber between the check valve and the piston

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3858489B1Piston-valve engagement in fluid sprayers
Publication Date: 2023.06.14 GRACO MINNESTOA INC
  • EP3858489B1 patent drawingFigure 1A
  • EP3858489B1 patent drawingFigure 1B
  • EP3858489B1 patent drawingFigure 2A

AI summary

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