High-Pressure Cleaner Start Valve Layout for Reliable Startup

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Solution Overview

Problem

High-pressure cleaning devices often experience engine overheating and stalling during startup due to unreliable operation of the start valve, which closes before the engine reaches its operating speed range, influenced by external parameters such as nozzle cross-section and other throttles in the main line.

Innovation Solution

The start valve is arranged in the main line downstream of the high-pressure pump, ensuring the full volume flow hits it undivided, allowing reliable and reproducible operation independent of external parameters, ensuring it only closes when the engine reaches its operating speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the start valve is arranged in the return line, then the high-pressure pump can pump liquid in a circle during start-up without working against high back pressure, but the start valve closes before the engine reaches operating speed due to unreliable operation influenced by external parameters

Engineering Contradiction:
Improveengine powerVSAvoidstart valve operation reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent introduces a bypass line as an intermediary element that allows a portion of the liquid flow to bypass the start valve. This mediator enables the start valve to operate reliably by receiving a dedicated, undivided volume flow from the high-pressure pump through the bypass line, independent of the main line throttles and nozzle cross-section variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the liquid flow path into two independent channels: the main line and the bypass line. The bypass line is specifically designed to supply a dedicated volume flow to the start valve, separating the start valve's operation from the influences of the main line's external parameters such as nozzle cross-section and throttles.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the start valve is arranged in the return line, then startup is facilitated, but the closing and opening times of the start valve vary under constant operating conditions due to volume flow division

Engineering Contradiction:
Improvestartup easeVSAvoidstart valve timing precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The bypass line acts as an intermediary that provides a dedicated, stable volume flow path to the start valve. This intermediary channel isolates the start valve's timing characteristics from the variable flow division in the main line, ensuring consistent and precise opening and closing times regardless of nozzle or throttle variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By segmenting the flow system into main line and bypass line, the patent creates an independent flow channel for the start valve. This segmentation ensures that the start valve receives a consistent volume flow proportion, making its operation timing precise and reproducible under constant operating conditions.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the start valve is arranged in the main line, then the full undivided volume flow hits the start valve for reliable operation, but the engine may overheat and shut down if the start valve closes too early

Engineering Contradiction:
Improvestart valve operation reliabilityVSAvoidengine temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The bypass line serves as a mediator that ensures the start valve receives sufficient undivided volume flow from the high-pressure pump to operate reliably. This dedicated flow path guarantees that the start valve closes only when the engine reaches its speed within the operating range, preventing premature closure that would cause overheating and shutdown.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 arrangement guarantees reliable engine startup by preventing premature closure of the start valve, allowing the high-pressure pump to reach sufficient speed and torque to handle pressure effectively, preventing overheating and stalling.

Implementation Method 1

a high-pressure pump (3) which, by means of a motor (4), conveys liquid from the suction chamber (9) to the pressure chamber (10)

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a start valve (22) which closes an outlet (25) of the return line (12) when a starting volume threshold value of the volume flow through the start valve (22) is reached or exceeded

Methodology Applied
Scientific EffectValve: Valve

Data Source

PatentEP4480592A1High-pressure cleaning device
Publication Date: 2024.12.25 ANDREAS STIHL AG & CO KG
  • EP4480592A1 patent drawingFigure 1
  • EP4480592A1 patent drawingFigure 2
  • EP4480592A1 patent drawingFigure 3

AI summary

The invention relates to a high-pressure cleaning device comprising a connection for a liquid source, a high-pressure pump (3), and a main line (5) through which liquid can be pumped from the connection (2) to a spray opening (6) of the main line (5) by means of the high-pressure pump (3). The main line (5) has a suction chamber (9) between the connection (2) and the high-pressure pump (3). The main line (5) has a pressure chamber (10) between the high-pressure pump (3) and the spray opening (6). The pressure chamber (10) is fluidically connected to the suction chamber (9) via a return line (12). The high-pressure cleaning device (1) includes a start valve (22). The high-pressure cleaning device (1) is designed such that the start valve (22) closes in such a way that no liquid can flow from the pressure chamber (10) into the suction chamber (9) through the return line (12) when the volume flow through the start valve (22) corresponds to at least a start volume threshold.The starting valve (22) is located in the main line (5) downstream of the high-pressure pump (3).