Segmented Liquid Flow Control Apparatus for Low Rate Precision

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Solution Overview

Problem

Conventional pumps struggle to accurately control low liquid flow rates, particularly below 10 milliliters per minute, and existing methods for achieving low flow rates in fuel injector testing and manufacturing are inefficient and prone to liquid heating.

Innovation Solution

A control apparatus comprising multiple supply conduits with associated control valves that allow incremental flow rate adjustments, enabling precise control of liquid flow rates down to 1 milliliter per minute by selectively opening or closing the conduits to a return path, thereby recirculating excess liquid and maintaining a stable flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional electrical pump is used to control liquid flow rate, then the pump can operate at higher flow rates, but it cannot accurately control low flow rates (below 10 millilitres/min) due to physical limitations

Engineering Contradiction:
Improveflow rate control precisionVSAvoidliquid flow rate
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention divides the single pump output into multiple parallel supply conduits (e.g., 19 conduits), each with its own control valve. This segmentation allows the system to achieve fine flow rate control at low levels by selectively opening or closing individual conduits, effectively creating discrete flow steps that enable precise control below 10 millilitres/min.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the fuel injector is used to supply liquid at very low flow rate, then low flow rate is achieved, but prolonged use causes heating of the liquid

Engineering Contradiction:
Improveliquid flow rateVSAvoidliquid temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The invention extracts the flow control function from the fuel injector itself and places it in the supply conduits with control valves. This allows the fuel injector to be used only briefly for initial flow establishment, while the majority of the time the system uses the segmented supply conduits to maintain low flow rates without the heating problem associated with prolonged injector operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If conventional pump calibration methods are used, then the pump can be calibrated, but the step-like flow rate profile prevents accurate calibration at low flow rates

Engineering Contradiction:
Improvecalibration accuracyVSAvoidflow rate control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration system is segmented into multiple supply conduits with individual control valves, allowing the creation of a fine-grained flow rate scale. This segmentation transforms the coarse step-like profile into a near-continuous adjustable flow rate, enabling accurate calibration across the entire range including low flow rates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the control parameter from single-pump voltage adjustment to multi-conduit valve positioning. By changing which conduits are open and how many, the system creates discrete flow rate steps that can be precisely controlled, allowing accurate calibration at low flow rates that were previously unachievable.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3250813B1Flow control method and apparatus
Publication Date: 2019.07.17 DELPHI TECH IP LTD
  • EP3250813B1 patent drawingFigure 1
  • EP3250813B1 patent drawingFigure 2~3
  • EP3250813B1 patent drawingFigure 4

AI summary

The present disclosure relates to a control apparatus (1) for controlling supply of a liquid. The control apparatus (1) has a reservoir (3) for storing a liquid. A plurality of like supply conduits (7) are connected to the reservoir (3). A control valve (14) is associated with each of the supply conduits (7). The control valves (14) are operable to control the flow of liquid through that supply conduit. The present disclosure also relates to a method for controlling supply of a liquid.