JPS6339582Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of air-cooled heat exchangers. This invention relates to an air-cooled heat exchanger that prevents deterioration.

Air-cooled heat exchangers used in oil coolers etc. send cooling air to the heat exchanger core 1 with a blower fan 2, and cool the liquid flowing inside the heat exchanger core 1 by exchanging heat with the air. A plate-fin type heat exchanger is often used for the heat exchanger core 1, and its configuration is such that two tube plates 11 are opposed to each other as shown in FIG. A fluid passage is formed by inserting a corrugated fin 13 into a passage whose end is closed with a spacer bar 12, and the direction of the corrugated fin 13 is changed so that one side is used as an air passage and the other side is used as a liquid passage to be cooled. ,
The side plates 14 are stacked alternately or at predetermined intervals, and the side plates 14 are placed outside the wave-shaped fins of the outermost air passage, and these are integrated by a method such as brazing. exchanger core 1
An inlet header tank 5 and an outlet header tank 6 are fixed to both open ends of the liquid passage 3 to be cooled.

In this heat exchanger core 1, while the liquid to be cooled introduced from the inlet header tank 5 is sent to the outlet header tank 6, the cooling air from the blower fan 2 below the core 1 exchanges heat in the passage 4, Cools the liquid to be cooled. However, in air-cooled heat exchangers, as the blower fan turns on and off, cracks occur near the outer side plate of the heat exchanger core and the outlet side of the header due to life deterioration.
There were problems such as leakage of the cooled liquid.

The purpose of this invention is to create an air-cooled heat exchanger that reduces the thermal strain that occurs when the blower fan is turned on and off, and has improved durability.

This idea was developed after examining the above-mentioned problems and discovering that the cause of excessive thermal strain is due to the following mechanism.
This idea has been completed.

In other words, this idea consists of laminating a plurality of corrugated fins and tube plates, closing them with a spacer bar to form passages, and connecting air passages and cooled liquid passages to the heat exchanger core, which is laminated with a blower fan. In an air-cooled heat exchanger that performs ventilation cooling, the outer side plate of the heat exchanger core is removed, and triangles are placed at the four corners of the air inflow side and/or air outflow side of the heat exchanger core, or two locations adjacent to the inlet/outlet header tank. This is an air-cooled heat exchanger characterized by a rectangular masking plate.

To explain the crack generation mechanism based on the explanatory diagram of the heat exchanger core in FIG. 2, in the air-cooled heat exchanger having the above-mentioned configuration,
However, when the fan 2 is in steady operation or stopped, the entire heat exchange core exhibits a nearly uniform temperature distribution, but after the blower fan 2 remains stopped, the fan 2
When the wavy fins of the air passage 4 and the cooled liquid passage 3 are activated, the liquid flows into the inlet header tank 5.
As it moves from the liquid to the outlet header tank 6, it is cooled, but the side plate 14 and the vicinity of the passage outlet of the outlet header tank 6 are not cooled as much as the cooled liquid passage 3, resulting in temperature imbalance. In this case, a thermal contraction misalignment occurs in the longitudinal direction of the side plate 14 and the cooled liquid passage 3, resulting in thermal distortion. As a result, tensile strain and bending strain due to rotation occur in the tube plates 11, 11 on both sides of the cooled liquid passage 3, and reverse strain is also added after the blower fan 2 stops, resulting in low cycle fatigue. There is a danger that cracks may occur and lead to accidents such as leakage of the cooled liquid. Further, the above-mentioned thermal contraction also occurs perpendicular to the longitudinal direction of the side plate 14 and the liquid passage 3 to be cooled, that is, in the flow direction of the air passage, and similar thermal distortion causes bending strain in the spacer bar 12 of the liquid passage 3 to be cooled. (Figure 2,
b, c).

Based on the above findings, this idea removes the outer side plate of the heat exchanger core and places triangles at the four corners of the air inflow side and/or air outflow side of the heat exchanger core, or at two points adjacent to the inlet/outlet header tank. By providing a rectangular masking plate in the heat exchanger, it corrects the imbalance in temperature distribution across the heat exchanger core that occurs during rapid start-up operation due to turning on and off of the fan, and greatly reduces the occurrence of thermal distortion. It is something.

This invention will be explained in detail below based on the drawings.
3 and 4 are explanatory views of the heat exchanger core of the air-cooled heat exchanger according to this invention.

To remove the side plate, as shown in Figure 3,
After integrally forming the side plate 14 by brazing, both ends of the side plate 14 may be cut and removed, and the wave-shaped fins do not need to be removed. It is also a good idea to assemble the heat exchanger core without side plates from the beginning.

The masking plate 20 is provided with triangular plates at the four corners of the air inflow side and/or air outlet side of the heat exchanger core, or rectangular flat plates at two locations adjacent to the inlet/outlet header tank, and its shape and dimensions are as follows:
The area occupied by the masking plate should be 1/1 of the total heat exchange area.
Desirably, the ratio is from 15 to 1/2; if it is less than 1/15, the effect of reducing thermal strain will be small, and if it exceeds 1/2, the efficiency as a heat exchanger will be too poor. Further, the masking plate is preferably installed on the cooling air inlet side because it has a high effect of reducing thermal strain, but it may be installed on the outlet side or on both sides. Further, the masking plate may be an isosceles triangular or rectangular flat plate, or may be a plate with holes.

By the way, using a heat exchange core with a performance of 301000Kcal/hr, the outside temperature is -5℃ and the temperature of the oil to be cooled.
In case of 50℃ condition, remove the side plate,
We also compared thermal strain between the heat exchanger core of the present invention having a masking plate and a conventional device. The masking plate of this invention uses isosceles triangular flat plates at the four corners of the cooling air inlet side and is installed to cover 1/8 of the heat exchange area of the heat exchange core, resulting in a heat exchange capacity of 287,000 Kcal/hr. , decreased by 4.7%. However, in thermal strain, plane strain is
It has been dramatically reduced from 2500μ to just 250μ, and the vertical distortion has been halved from the conventional 1000μ to 570μ, indicating a significant improvement in durability.

[Brief explanation of the drawing]

Figure 1 is a side view of an air-cooled heat exchanger, and Figure 2 is a cross-sectional view of the heat exchange core. shows. FIG. 3 is an explanatory view of the heat exchanger core according to this invention with side plates removed, and FIG. 4 is an explanatory view of the bottom of the heat exchanger core according to this invention and an enlarged explanatory view of the masking plate portion. Fifth
The figure is an explanatory bottom view of another heat exchange core according to this invention. 1...Heat exchanger core, 2...Blower fan, 3...
...Liquid passage to be cooled, 4...Air passage, 5...Inlet header tank, 6...Outlet header tank, 11...
...tube plate, 12...spacer bar,
13...Wave type fin, 14...Side plate,
20...Masking plate.

Claims (1)

[Scope of utility model registration request] An air-cooled heat exchanger core consisting of a stack of multiple corrugated fins and tube plates, closed with spacer bars to form a passage, and a stacked air passage and cooled liquid passage, which is cooled by ventilation using a blower fan. In the exchanger, the side plates of the heat exchanger core are removed, and triangular masking plates are provided at the four corners of the air inflow side and/or air outflow side of the heat exchanger core, or rectangular masking plates are provided at two locations adjacent to the inlet/outlet header tank. An air-cooled heat exchanger characterized by: