HVLP Spray Gun Air Control Using Hose Pressure Storage

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Solution Overview

Problem

Conventional high volume, low pressure (HVLP) spray systems operate continuously, leading to excessive motor wear, energy consumption, heat generation, and noise, as the motor remains on even when not in use, requiring manual switching and time to resume spraying.

Innovation Solution

The system incorporates a control circuitry and sensor to manage power to the blower, allowing the blower to reduce or stop operation when the trigger is not actuated, utilizing the pneumatic circuit as an accumulator to provide instant air flow upon trigger activation, even when the blower is restarting or at low power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor operates continuously to maintain pressurized air in the system, then the air supply is always ready for spraying, but the motor experiences excessive wear, high energy consumption, heat generation, and noise

Engineering Contradiction:
Improveair supply readinessVSAvoidmotor energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary action by filling the pneumatic circuit with pressurized air before the user actually needs to spray. The motor runs in advance to charge the pneumatic circuit, then stops when the circuit is sufficiently pressurized. This allows the system to have air ready for spraying without continuous motor operation, reducing energy consumption while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The motor operates periodically rather than continuously - it runs when the pneumatic circuit pressure drops below a threshold and stops when pressure is sufficient. This periodic operation pattern reduces overall energy consumption, motor wear, and heat generation while ensuring air is available when needed for spraying.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If the motor is manually turned off to reduce energy consumption and wear, then energy efficiency improves, but the system requires manual reactivation and time to refill air before spraying can resume

Engineering Contradiction:
Improvemotor energy consumptionVSAvoidspray resumption convenience
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system performs self-service by automatically monitoring pneumatic circuit pressure and reactivating the motor when pressure drops below the threshold. The control circuitry detects pressure conditions and autonomously restarts the motor without user intervention, eliminating the need for manual reactivation while maintaining energy efficiency through pressure-based control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from the pressure sensor to automatically control motor operation. When the sensor detects that pneumatic circuit pressure has dropped below the threshold, it triggers motor restart. This closed-loop feedback mechanism ensures the system maintains adequate air pressure while minimizing unnecessary motor running, improving both energy efficiency and operational convenience.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the motor is turned off during inactivity, then energy consumption and motor wear are reduced, but the pneumatic circuit loses pressure and cannot immediately resume spraying

Engineering Contradiction:
Improvemotor energy consumptionVSAvoidspray resumption speed
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The system performs preliminary action by maintaining pressurized air in the pneumatic circuit through automatic motor restart when pressure drops. This ensures that when the user activates the spray trigger, pressurized air is already available in the circuit, enabling immediate spray resumption without waiting for the motor to accelerate and refill the system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The motor operates periodically to maintain pneumatic circuit pressure at adequate levels. By monitoring pressure and restarting the motor when needed, the system ensures continuous availability of pressurized air in the pneumatic circuit, enabling rapid spray resumption while minimizing overall motor run time to reduce energy consumption.

Inventive Principle:
Principle #19Periodic action

4Reliability

If the motor operates at full power continuously, then sufficient pressurized air is always available, but noise and heat generation increase significantly

Engineering Contradiction:
Improveair supply availabilityVSAvoidmotor noise and heat
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The motor operates periodically at full power only when needed to recharge the pneumatic circuit, rather than running continuously. This periodic full-power operation ensures sufficient pressurized air is available while dramatically reducing cumulative noise and heat generation compared to continuous operation, as the motor is off during periods when pressurized air is already stored in the pneumatic circuit.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3566780B1On-demand high volume, low pressure spray system
Publication Date: 2023.07.05 GRACO MINNESTOA INC
  • EP3566780B1 patent drawingFigure 1
  • EP3566780B1 patent drawingFigure 2
  • EP3566780B1 patent drawingFigure 3

AI summary

Various embodiments concern a sprayer having a blower that outputs a HVLP flow of air into a hose, the hose connecting with a spray gun. A pressure sensor measures pressure of the HVLP air within the hose via a tube that branches from a fitting to which the hose connects. If the sensor indicates that the pressure level has increased above a threshold amount, indicating that the trigger of the spray gun is not being actuated, then power output to the blower is reduced (e.g., stopped). HVLP air is trapped within the hose by two valves when the trigger is not actuated. When the sensor indicates that the pressure level has decreased, corresponding to release of the trapped HVLP air into the gun for spraying by actuation of the trigger, power to the blower is increased (e.g., resumed).