Complex heat source apparatus

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Solution Overview

Problem

Existing complex heat source apparatuses face inefficiencies in thermal management and adjustable air-fuel mixture supply, particularly when only one burner is operational, leading to reduced thermal efficiency and lack of independent control during simultaneous operation of both burners.

Innovation Solution

A complex heat source apparatus with an on-off valve at one burner's connection to the air supply passage and a flow control valve at the other burner's connection, allowing independent adjustment of air-fuel mixture supply through the rotational speed of the fan and flow control valve, respectively, ensuring precise control and reduced costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a common fan supplies air to both burners, then costs are reduced, but thermal efficiency decreases when only one burner is operational due to unwanted air flow cooling the idle heat exchanger

Engineering Contradiction:
ImprovecostVSAvoidthermal efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The air supply system is segmented into two independent paths: one path controls air flow to the first burner and another path controls air flow to the second burner. This allows independent control of air supply to each burner, preventing unwanted air flow from cooling idle heat exchangers while maintaining cost efficiency through shared fan operation.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If on-off valves are installed at both burner connection portions, then independent air supply control is achieved, but device complexity increases

Engineering Contradiction:
Improveindependent air supply controlVSAvoidnumber of valves
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Different control strategies are applied at different locations: an on-off valve is installed at the first burner connection for simple binary control, while a flow control valve is installed at the second burner connection for continuous flow adjustment. This localized differentiation achieves independent control functionality while minimizing overall device complexity.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If flow control valves are installed at both burners, then independent air-fuel mixture control is achieved, but costs and device complexity increase significantly

Engineering Contradiction:
Improveindependent air-fuel mixture controlVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control system uses asymmetric valve configuration where the first burner uses a simple on-off valve and the second burner uses a flow control valve. This asymmetric arrangement provides sufficient independent control capability for both burners while avoiding the excessive complexity and cost of installing flow control valves at both locations.

Inventive Principle:
Principle #4Asymmetry

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

Enables independent adjustment of air-fuel mixture supply to each burner, maintaining optimal combustion levels and reducing costs by eliminating the need for complex cooperative control between fan speed and flow control valve during simultaneous operation.

Implementation Method 1

a single fan which supplies primary air

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

both the first and the second burners are constituted by Bunsen burners such as rich and lean combustion burners

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

a first heat exchanger for supplying hot water; a second heat exchanger for space heating

Methodology Applied
Scientific EffectHeat transfer:

Data Source

PatentEP3156728B1Complex heat source apparatus
Publication Date: 2018.02.07 RINNAI CORP
  • EP3156728B1 patent drawingFigure 1

AI summary

[Problems] A complex heat source apparatus is provided with: first and second, i.e., a total of two, heat exchangers (11, 12); and first and second, i.e., a total of two, burners (21, 22). A single fan (6) is interposed in a common air supply passage (5) which is connected to both the burners. A downstream end of a gas supply passage (7) which has interposed therein a flow control means (73) is connected to that portion of the air supply passage (5) which is on an upstream side or a downstream side of the fan (6). The air-fuel mixture of the primary air and the fuel gas is arranged to be supplied to both the burners (21, 22) through the air supply passage (5), and the amount of the air-fuel mixture supply to each of the first and the second burners (21, 22) is made to be independently adjusted. [Solving Means] An on-off valve (8) is provided in a connection portion (21a) between the first burner (21) and the air supply passage (5), and a flow control valve (9) is provided in a connection portion (22a) between the second burner (22) and the air supply passage (5). The amount of the air-fuel mixture supply to the first burner (21) is adjusted by the rotational speed of the fan (6), and the amount of the air-fuel mixture supply to the second burner (22) is adjusted by the rotational speed of the fan (6).