Volumetric Flow Measuring Device Bypass Line Segmentation

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Solution Overview

Problem

Existing flow sensors in water pipe systems are unable to accurately measure small flow rates, leading to decreased efficiency and control accuracy of circulation pumps, particularly in systems that circulate hot and cold water for hygiene and service purposes.

Innovation Solution

A device with a bypass line and flow resistance element that divides the water flow into a main and partial flow, allowing for the use of a flow sensor sensitive to smaller volume flows, and a motor-controlled valve to dynamically adjust the flow path, ensuring accurate measurement of total volume flow across a range of 0 to 100 l/min with ±1 l/min accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a common flow sensor is used in the water pipe, then the device structure remains simple, but the measurement precision deteriorates for small flow rates

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The water flow is segmented into a main flow through the water pipe and a bypass flow through the bypass line. The bypass line with flow resistance element creates a measurable partial flow that can be measured by a standard flow sensor, while the main flow continues through the pipe. This segmentation allows accurate measurement of small total flows by measuring the bypass portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass line acts as an intermediary path that diverts a portion of the water flow through the flow sensor. This intermediary measurement path enables indirect measurement of the main flow through calibration relationships, allowing accurate measurement without placing the sensor directly in the main flow path.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the measurable range is extended to include small flow rates, then the measurement precision for small flows improves, but the device complexity increases

Engineering Contradiction:
Improvemeasurable rangeVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flow measurement system is segmented into measurable and non-measurable portions. The bypass line with flow resistance element creates a measurable partial flow that extends the sensor's effective measurement range down to very small flow rates (0-100 l/min), while the main flow path remains simple.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If a flow sensor sensitive to small volume flows is used, then the measurement precision for small flows improves, but the pressure loss increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidpressure loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The total flow is segmented into main flow and bypass flow. The flow resistance element in the bypass line is designed to create only a small pressure drop (0.5-2 bar) that is sufficient to drive the bypass flow through the sensor without significantly impacting the main system pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow resistance element is designed with specific local properties (resistance value) that are optimized for the bypass line conditions. This localized resistance creates the necessary pressure differential for measurement while maintaining overall system efficiency.

Inventive Principle:
Principle #3Local quality

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

Enhances measurement accuracy and range, allowing for precise control of circulation pumps and heat exchanger operation by accurately measuring small flow rates and maintaining low pressure loss, thereby improving system efficiency.

Implementation Method 1

a flow sensor based on the vortex measuring principle is provided

Methodology Applied
Scientific EffectVortex measuring principle: Kármán Vortex Street

Implementation Method 2

a flow resistance element provided in the water line and between the inlet and outlet openings. The flow resistance element ensures that, when flow passes through the water line, at least the bypass line is also flowed through

Methodology Applied
Scientific EffectFlow resistance: Pressure Drop

Data Source

PatentEP3933349B1Volumetric flow measuring device and water heating module using such a device
Publication Date: 2024.03.06 GEBR KEMPER GMBH CO
  • EP3933349B1 patent drawingFigure 1~2
  • EP3933349B1 patent drawingFigure 3
  • EP3933349B1 patent drawingFigure 4

AI summary

The present invention relates to a device for measuring the volumetric flow rate through a water pipe (2), comprising the water pipe (2) with an inlet and an outlet opening (4, 6) as well as a wedging opening and a threading opening (12, 14) provided between the inlet and the outlet opening (4, 6), a bypass pipe (16) connected to the wedging opening and the threading opening (12, 14), a flow resistance element (18) provided in the water pipe (2) and between the wedging opening and the threading opening (12, 14), and a flow sensor (20) provided in the bypass pipe (16). Furthermore, the present invention provides a module for water heating with such a device.