Two-Stage Pump Segmented Chambers for Flow Efficiency

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Solution Overview

Problem

Existing two-stage pumps face challenges in achieving high volumetric efficiency, precise limit pressure setting, and operational reliability due to shared pressure valves and interconnected pumping chambers, leading to inefficiencies and wear on reciprocating pistons.

Innovation Solution

The design features separate reciprocating pump elements with independent pumping chambers and valves, a switching valve that routes flow efficiently to a tank at the limit pressure, and a compact housing configuration that allows for precise pressure control and low-loss flow paths, ensuring high volumetric efficiency and structural simplicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the low-pressure and high-pressure delivery chambers are connected via the suction valve of the high-pressure delivery chamber, then the pump can deliver high flow rates at low pressures, but the pressure valve must be impractically large to cope with combined delivery flows

Engineering Contradiction:
Improvedelivery flow rateVSAvoidpressure valve size
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the delivery system into separate low-pressure and high-pressure delivery chambers with independent pressure valves. Each chamber handles its own flow separately, eliminating the need for an oversized pressure valve that would be required to handle combined flows simultaneously. The low-pressure chamber has its own pressure valve sized for low-pressure flows, and the high-pressure chamber has its own pressure valve sized for high-pressure flows.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the low-pressure reciprocating piston is connected to the high-pressure reciprocating piston with a common return spring, then the structure is simplified, but the reciprocating pistons are subject to heavy wear

Engineering Contradiction:
Improvestructural simplicityVSAvoidpiston wear
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent separates the drive mechanisms for the low-pressure and high-pressure reciprocating pistons, giving each piston its own return spring. This segmentation prevents the heavy wear that would occur if both pistons were connected and subjected to combined forces, while maintaining reasonable structural complexity through the use of a common drive shaft.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the two pump elements work independently with separate pumping chambers and valves, then volumetric efficiency increases, but the device complexity increases

Engineering Contradiction:
Improvevolumetric efficiencyVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines two independently operating pump elements into a single integrated device with a common drive shaft and housing. While the pump elements operate independently with separate pumping chambers and valves to maintain high volumetric efficiency, they are merged into one compact unit that reduces overall device complexity compared to having completely separate pump systems.

Inventive Principle:
Principle #5Merging (Combining)

4Loss of energy

If the switching valve routes low-pressure flow to the tank when pressure exceeds limit pressure, then energy losses are reduced, but the housing channel complexity increases

Engineering Contradiction:
Improveflow lossVSAvoidhousing channel configuration
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent uses a switching valve as an intermediary device that automatically routes low-pressure flow to the tank when the limit pressure is exceeded. This mediator component manages the complex flow path logic without requiring complex housing channels, as the switching valve itself handles the decision-making and routing function.

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 configuration enables high volumetric efficiency, precise limit pressure setting, and reduced wear on components, allowing the two-stage pump to efficiently manage flow rates and reach high working pressures with minimal losses and structural complexity.

Implementation Method 1

a closing element (11) that can be adjusted against a prestressing spring (10) from the shut-off position shown to an open position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the pressure in the pressure outlet keeping the pressure valve of the low-pressure pump element closed, so that no part of the delivery flow

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2634426B1Two-stage pump
Publication Date: 2014.05.14 HAWE HYDRAULIK SE
  • EP2634426B1 patent drawingFigure 1~2
  • EP2634426B1 patent drawingFigure 3~4
  • EP2634426B1 patent drawingFigure 5

AI summary

The pump (P) has a high-pressure and low-pressure pumping element (H,N) for small and high flow rate, and common pressure outlet (2). A switching valve (9) arranged between low-pressure pumping element and tank is opened to tank dependent on pressure in discharge outlet, such that piston pump elements of two pumping elements are equipped with suction and pressure valves (4,5). A common housing is shared by suction and discharge valves and changeover valve (9), so that piston (16,17) is divided into separate high-pressure and low-pressure delivery spaces (3,6).