Brazed Plate Heat Exchanger With Embedded Temperature Probe
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Solution Overview
Problem
Existing brazed plate heat exchangers lack precise local temperature and heat flow measurements, which are difficult to implement without disturbing the operation or increasing the exchanger's size, and current methods are intrusive, costly, and complex.
Innovation Solution
A method for manufacturing a brazed plate heat exchanger that integrates temperature probes into grooves in the plates before brazing, ensuring non-intrusive local temperature and heat flow measurements by using a sheath and brazing agent to maintain thermal contact and minimize thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature probes are inserted into tubes in grooves after brazing, then local temperature measurement is enabled, but thermal resistance increases and measurement accuracy degrades
Solution Approach 1:
The temperature probe is inserted into the groove before brazing, so that the brazing agent can fill the space between the probe and groove walls during the brazing process, creating direct thermal contact. This preliminary action eliminates the need for post-brazing probe insertion through tubes, thereby reducing thermal resistance and improving measurement accuracy.
Solution Approach 2:
The brazing agent acts as an intermediary material that fills the gap between the temperature probe and the groove walls. During brazing, the molten brazing agent flows into the space surrounding the probe, creating a thermal bridge that enhances heat transfer from the plate to the probe, thus reducing thermal resistance.
2Productivity
If heat exchangers are manufactured with compact monolithic construction, then pressure losses are reduced and exchange surface area is increased, but local temperature and heat flow measurements become difficult
Solution Approach 1:
The plate is segmented by creating a groove that divides the monolithic structure into regions. This groove provides a dedicated pathway for the temperature probe, allowing local measurements without compromising the overall compact monolithic construction. The segmentation is minimal and does not significantly affect the heat exchange efficiency.
Solution Approach 2:
The groove structure serves multiple functions: it provides a mounting location for the temperature probe, acts as a channel for the brazing agent to ensure thermal contact, and maintains the compact construction of the heat exchanger. This multi-functional design enables measurement capability while preserving heat exchange efficiency.
3Loss of information
If existing temperature measurement methods are implemented, then local temperature data can be obtained, but the complexity of support parts and implementation increases
Solution Approach 1:
The temperature measurement function is merged into the manufacturing process itself. The groove is created during plate fabrication, and the probe is integrated before brazing, combining the measurement system with the heat exchanger structure. This eliminates the need for separate complex support parts and simplifies implementation.
Solution Approach 2:
The brazing process itself serves the dual purpose of joining the heat exchanger components and creating thermal contact for the temperature probe. The molten brazing agent automatically fills the gap between the probe and groove walls, eliminating the need for additional sealing or thermal contact mechanisms.
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 precise local temperature and heat flow measurements within the exchanger without altering its operation or size, improving measurement accuracy and reducing thermal resistance.
Implementation Method 1
brazing the assembly of plates, including the first flat product, to the second flat product
Implementation Method 2
diffusion of at least a portion of the brazing agent into the first and second flat products
Implementation Method 3
at least a portion of the free space provided between the temperature probe and the internal walls of the groove being filled with solidified brazing agent
Data Source
Figure 1
Figure 2(a)~2(e)
Figure 3(a)~3(c)
AI summary
The invention relates to a method for manufacturing a heat exchanger (1) of the brazed plate and fin type comprising the following steps: a) stacking with spacing a set of plates (2) parallel to each other and in a longitudinal direction (z) so as to define between said plates (2) a plurality of passages (3) adapted for the flow along the longitudinal direction (z) of a first fluid to be connected for heat exchange with at least a second fluid, said plates (2) being delimited by a pair of longitudinal edges (4a) extending along the longitudinal direction (z) and a pair of lateral edges (4b) extending along a lateral direction (x) perpendicular to the longitudinal direction (z), b) forming at least one of the plates (2) stacked in step a) by superimposing, along a stacking direction (y) perpendicular to the longitudinal (z) and lateral (x) directions,at least one first flat product (21) and a second flat product (22) stacked one on top of the other, at least one of the first and second flat products (21, 22) comprising at least one groove (12) extending parallel to the plates (2) and opening outwards from the stack formed in step a) by at least one opening (5) in a lateral or longitudinal edge (4a, 4b), c) arranging at least one brazing agent (30) between the first flat product (21) and the second flat product (22), d) arranging at least one temperature probe (14) in the groove (12), a free space being provided between at least a portion of the temperature probe (14) on the one hand and the internal walls of the groove (12) on the other hand, e) brazing the assembly of plates (2), including the first flat product (21) onto the second flat product (22), with fusion of the brazing agent brazing (30) and diffusion of at least part of the brazing agent (30) into the first flat product (21) and the second flat product (22),at least part of the free space between the temperature probe (14) and the internal walls of the groove (12) being filled with solidified brazing agent (30).