Process air unit for heating process air

Solution Overview

Problem

Conventional process air units for heating process air in workpiece processing systems are energetically inefficient due to the co-current flow of flue gas and process air, which limits heat transfer and requires excessive energy consumption.

Innovation Solution

A process air unit design that employs a countercurrent principle, where the process air flows over a tube bundle arrangement oriented transversely to the flow direction, upstream of the combustion chamber, allowing for enhanced heat transfer and energy efficiency by maintaining a temperature difference between the flue gas and process air flows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the combustion chamber is arranged first in the process air duct with co-current flow, then the structure is simpler, but the energy efficiency is poor due to limited heat transfer

Engineering Contradiction:

Improveenergy efficiencyVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent inverts the conventional co-current flow arrangement by implementing a countercurrent flow system where the process air flows in the opposite direction to the flue gas. The process air enters at the first duct end and flows over the tube bundle arrangement, while the flue gas flows through the tubes in the opposite direction, maximizing the temperature difference and heat transfer efficiency throughout the entire heat exchanger length.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a tube bundle arrangement as an intermediary heat transfer medium between the flue gas and the process air. The tube bundle with multiple tubes oriented transversely to the process air flow direction allows flue gas to flow through the tubes while process air flows over the tubes, creating an efficient indirect heat transfer path that maintains temperature differences and maximizes energy transfer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If conventional co-current heating is used, then the device structure is simpler, but excessive energy is consumed to heat the process air

Engineering Contradiction:

Improveenergy consumptionVSAvoidheat transfer arrangement

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent inverts the conventional co-current flow arrangement by implementing a countercurrent flow system where the process air flows in the opposite direction to the flue gas. The process air enters at the first duct end and flows over the tube bundle arrangement, while the flue gas flows through the tubes in the opposite direction, maximizing the temperature difference and heat transfer efficiency throughout the entire heat exchanger length.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The countercurrent flow arrangement ensures continuous and efficient heat transfer along the entire length of the heat exchanger. By maintaining a temperature difference between the flue gas and process air throughout the entire flow path, the system achieves continuous useful heat transfer action, preventing energy waste and maximizing the utilization of thermal energy from the flue gas.

Inventive Principle:

Principle #20Continuity of useful action

3Loss of energy

If the tube bundle arrangement is placed upstream of the combustion chamber, then countercurrent flow is achieved for better heat transfer, but the device geometry becomes more complex

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidcombustion chamber geometry

Core Design Contradiction:

Loss of energyVSShape

Solution Approach 1:

The patent segments the heat transfer function into two distinct components: the tube bundle arrangement for indirect heat transfer from flue gas, and the combustion chamber for flame heating. This segmentation allows each component to be optimized independently - the tube bundle for efficient countercurrent heat exchange and the combustion chamber for its specific heating function, thereby managing geometric complexity through functional division.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a tube bundle arrangement as an intermediary heat transfer medium between the flue gas and the process air. The tube bundle with multiple tubes oriented transversely to the process air flow direction allows flue gas to flow through the tubes while process air flows over the tubes, creating an efficient indirect heat transfer path that maintains temperature differences and maximizes energy transfer.

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 design significantly increases energy efficiency in heating process air, allowing for reduced energy consumption and simplified combustion chamber geometry, making it suitable for high heat requirement applications like drying and hardening of painted workpieces.

Implementation Method 1

a tube bundle arrangement being connected to the combustion chamber and comprising at least one tube bundle having a plurality of tubes through which the flue gas from the combustion chamber can flow, wherein the plurality of tubes of the at least one tube bundle is oriented transversely to the process air flow direction and is arranged at least partially within the process air duct, so that they are overflowed by the process air and thereby transfer heat from the flue gas to the process air

Methodology Applied

Scientific EffectHeat transfer: Convection

Implementation Method 2

transfer heat from the flue gas to the process air

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a combustion chamber for burning a combustion air

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 4

this tube bundle arrangement is arranged, with respect to the process air flow direction, upstream of the combustion chamber in the process air duct... creates a countercurrent principle in which the material flows of the process air to be heated and the flue gas run in opposite directions through the process air duct, as a result of which there is always a temperature difference between these material flows

Methodology Applied

Scientific EffectCountercurrent flow: Convection

Data Source

PatentUS20240377102A1Process air unit for heating process air

Publication Date: 2024.11.14 DUERR SYST AG

AI summary

A process air unit (20) for heating a process air (21) for a workpiece processing system comprises a process air duct (22) through which a process air (21) can flow, a combustion chamber (30) for burning a combustion air, which is overflowed by the process air (21) in the process air duct (22) and thereby transfers heat to the process air (21), and a tube bundle arrangement (35) connected to the combustion chamber, which comprises at least one tube bundle (36) having a plurality of tubes (38) through which the flue gas (34) from the combustion chamber (30) can flow. The plurality of tubes (38) of the at least one tube bundle (36) is oriented in the process air duct (22) transversely to the process air flow direction, so that they are overflowed by the process air (21) and thereby transfer heat from the flue gas (34) to the process air (21), and the tube bundle arrangement (35) is arranged, with respect to the process air flow direction, upstream of the combustion chamber (30) in the process air duct (22) in order to achieve increased energy efficiency.