Piston Pump Hydraulic Circuit Two-Phase Pre-Compression

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Solution Overview

Problem

Existing piston pumps with differential cylinder drives face challenges in maintaining continuous and uniform delivery of materials, particularly when conveying thick or pulpy substances, due to pressure fluctuations and vibrations caused by inadequate pre-compression and abrupt loading of delivery pistons.

Innovation Solution

A method involving a hydraulic circuit that divides pre-compression into two phases, using a main hydraulic pump for constant pressure and an additional hydraulic pump for accelerated suction, ensuring continuous delivery by equalizing pressure levels and reducing vibrations through parallel operation of delivery pistons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single hydraulic pump is used to drive the differential cylinder during pre-compression, then the device complexity is reduced, but the delivery uniformity deteriorates due to pressure fluctuations and vibrations

Engineering Contradiction:
Improvehydraulic circuit complexityVSAvoiddelivery uniformity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The pre-compression process is divided into two distinct phases: a first pre-compression phase driven by an auxiliary hydraulic pump, and a second pre-compression phase driven by the main hydraulic pump. This segmentation allows each pump to operate under optimized conditions, with the auxiliary pump handling initial compression and the main pump completing the process, thereby maintaining delivery uniformity while managing system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary hydraulic pump performs preliminary pre-compression of the material in the delivery cylinder before the main hydraulic pump takes over. This preliminary action prepares the material and equalizes pressure levels in advance, preventing pressure fluctuations and vibrations when the main pump begins operation, thus ensuring smoother and more uniform delivery

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the delivery piston is abruptly loaded during pre-compression, then the productivity is improved by faster material ejection, but the delivery uniformity deteriorates due to vibrations and pressure fluctuations

Engineering Contradiction:
Improvematerial ejection speedVSAvoiddelivery uniformity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The auxiliary hydraulic pump performs preliminary pre-compression and equalizes pressure levels before the main hydraulic pump begins rapid material ejection. This preliminary action prepares the system to handle the abrupt loading without causing harmful vibrations or pressure fluctuations, allowing high productivity while maintaining delivery uniformity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The auxiliary hydraulic pump provides beforehand cushioning by performing initial pre-compression and stabilizing pressure levels in the delivery cylinder. This cushioning effect protects the system from the adverse effects of abrupt loading when the main pump operates at high speed, preventing vibrations and pressure fluctuations that would otherwise compromise delivery uniformity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Power

If pre-compression is performed at high pressure from the start, then the material ejection efficiency is improved, but the device complexity increases due to the need for dual hydraulic pumps with different pressure levels

Engineering Contradiction:
Improvepre-compression pressureVSAvoidhydraulic pump system
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The pre-compression process is segmented into two phases with different pressure levels: the auxiliary hydraulic pump operates at lower pressure for initial compression, and the main hydraulic pump operates at higher pressure for final compression and ejection. This segmentation allows the system to achieve high pre-compression pressure while using pumps optimized for their respective pressure ranges, managing overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary hydraulic pump performs preliminary pre-compression at lower pressure before the main hydraulic pump applies high pressure. This preliminary action at reduced pressure simplifies the requirements for the high-pressure system, as the auxiliary pump handles the initial compression needs, allowing the main pump to focus on high-pressure ejection without needing to handle the entire pressure range from zero

Inventive Principle:
Principle #10Preliminary action

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 approach enables continuous, error-free, and uniform conveying of materials by managing pressure fluctuations and vibrations, ensuring smooth transitions between suction and ejection phases, thus preventing material sagging and line vibrations.

Implementation Method 1

the hydraulic circuit effects a pre-compression of the sucked-in material in the delivery cylinder with a first delivery piston speed by applying the hydraulic fluid to the associated differential cylinder at a first volume flow and a first pressure

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

in a first phase the hydraulic circuit effects the pre-compression of the sucked-in material in the delivery cylinder with a first delivery piston speed by applying the hydraulic fluid to the associated differential cylinder at a first volume flow and a first pressure, and in a second, subsequent phase the hydraulic circuit effects the pre-compression of the sucked-in material in the delivery cylinder with a second delivery piston speed which is lower than the first delivery piston speed by applying the hydraulic fluid to the associated differential cylinder at a second volume flow which is lower than the first volume flow and a second pressure which is higher than the first pressure

Methodology Applied
Scientific EffectHydraulic fluid flow: Hydraulic Press

Data Source

PatentEP3894701B1Piston pump and method for operating a piston pump
Publication Date: 2024.05.22 SCHWING GMBH
  • EP3894701B1 patent drawingFigure 1
  • EP3894701B1 patent drawingFigure 2
  • EP3894701B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a piston pump comprising: a differential cylinder drive (1) having at least two differential cylinders (2, 3) for driving at least two delivery pistons that can move in delivery cylinders, wherein each delivery piston is driven via an associated differential cylinder (2, 3) of the differential cylinder drive (1) in order to operate the piston pump; and a hydraulic circuit (4) for driving the differential cylinder drive (1) by supplying hydraulic fluid. Moreover, the invention relates to a piston pump for carrying out the method.