JPH0625796Y2 - Heat exchanger for instant hot water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a heat exchanger for an instantaneous hot water storage type water heater using domestic petroleum.

(Prior Art) In a conventional heat exchanger, as shown in FIG. 5, a lower header 2 having a water supply connection port 1 and an upper header 4 having a hot water supply connection port 3 are connected by an endothermic water pipe 6 with endothermic fins 5a. It is configured. Further, the endothermic water pipe 6 with the endothermic fins 5a is normally formed by penetrating a plurality of endothermic water pipes 6 through a large number of endothermic fins 5a on a strip, and expanding or brazing the endothermic water pipes 6, or expanding or brazing. The endothermic water pipe 6 is fixed by fixing the endothermic fins 5a and the endothermic water pipes 6 together and passing the combustion gas in the direction of arrow B in FIG. 6, and bringing the endothermic fins 5a and the endothermic water pipe 6 into contact with the hot combustion gas. It exchanges heat with the water flowing inside.

(Problems to be solved by the invention) On the other hand, in the configuration of the above invention, the hot water storage amount is 7 to 15 in order to keep the time from ignition to hot water release within 2 minutes.
Combustion ON / OFF control is performed to reduce the temperature to a certain degree and stabilize the hot water temperature. This ON / OFF interval is about 30 seconds, and assuming that the operating time is 1 hour per day, if you request the service life of the equipment for 10 years,
The number of ON / OFF repetitions reaches about 450,000 times, and the ON / OFF combustion causes the heat exchanger to undergo a heat cycle. Particularly, in the endothermic water pipe with endothermic fins, the endothermic fins 5a are directly exposed to the combustion gas, so that the temperature rises abruptly and thermally expands as compared with other portions of the heat exchanger, and c and c in FIG. As shown by the arrow ', a force for pushing the endothermic water pipe 6 acts, and at the same time, a temperature difference occurs between the endothermic fins 5a at the upper and lower sides of the combustion gas inlet side and outlet side. Then, as shown by the arrows d and d ', a force that distorts the endothermic water pipe with endothermic fins acts.

That is, since both ends of the endothermic water pipe with endothermic fins are fixed by the lower header 2 and the upper header 4, stress is generated in the upper header and the connecting portion between the lower header and the endothermic water pipe.

In addition, even if the entire heat absorbing water pipe with heat absorbing fins is taken,
Since the central portion of the plan view has a particularly high temperature distribution as shown in Fig. 5, the force of bending the endothermic water pipe acts as shown by the dotted line in Fig. 5 to generate stress on the pipe wall of the endothermic water pipe.

Therefore, there is a drawback in that the heat exchanger is repeatedly cracked to cause water leakage and shorten the life of the device.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a heat exchanger that is not damaged by thermal stress.

(Means for Solving the Problems) The present invention will be described with reference to FIGS. 1 to 3 corresponding to the configuration and embodiment of the present invention for achieving the above object. A plurality of fins 5a are penetrated by a plurality of endothermic water pipes 6 and a lower header 2 having a water supply connection port 1 at one end of the endothermic water pipe 6 and an upper header 4 having a hot water supply connection port 3 at the other end
In the heat exchanger 7 in which the heat-absorbing water pipes 6 are connected to each other, a plurality of the heat-absorbing water pipes 6 are arranged only in the horizontal direction, and a notch portion is formed upward from the lower end of the heat-absorbing fins 5 in the middle of the heat-absorbing water pipes 6 adjacent to the heat-absorbing water pipes 6. a is provided, and the endothermic fins 5 directly above the endothermic water pipes 6
A technical means is provided in which a notch b is provided from the upper end to the vicinity of the endothermic water pipe 6.

(Operation) The present invention absorbs the dimensional change due to the thermal expansion by changing the width of the notches a and b by the above-mentioned means even when the heat absorbing fins are thermally expanded by combustion, and further the heat absorbing water pipe is Since they are arranged only in the horizontal direction, not in the vertical direction, the temperature difference between the upper and lower sides of the heat absorbing fins is reduced, and the thermal stress in each part of the heat exchanger is relaxed.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

Reference numeral 7 denotes a plurality of endothermic fins 5 formed of a metal such as aluminum or the like and penetrating a plurality of endothermic fins 5 formed of a metal tube such as copper, and penetrating one end of the endothermic water pipe 6 to the water supply connection port 1 Is a heat exchanger for a momentary hot water storage type water heater in which an upper header 4 having a hot water supply connection port 3 is connected at the other end, and the heat exchanger 7 is provided with a petroleum burner 8 for combustion. Upper header 4 above chamber 9
Is fixed with an inclination so that the lower header 2 faces downward.

a is a notch formed in the height direction from the lower end of the endothermic fin 5 in the middle of the endothermic water pipe 6 and the endothermic water pipe 6 from the upper end of the endothermic fin 5 above the endothermic water pipe 6 It is a notch portion formed up to.

The position of the notch a from the lower end of the fin is the portion that most contributes to heat exchange because the inside of the circumference whose radius is the distance from the center of the endothermic water pipe 6 to the lower end of the endothermic fin 5 is the portion that contributes most to heat exchange. The center of the gap between the adjacent endothermic water pipes 6 is avoided. Further, the position of the notch b from the upper end of the fin has a similar effect even if it is directly above or near the notch a from the lower end of the fin, as shown by the dotted line in FIG.
The connected part of the heat absorbing fin becomes small and the strength cannot be maintained, the handling property for manufacturing and storing the heat absorbing fin is poor, and the workability when penetrating the heat absorbing water pipe into the heat absorbing fin is significantly deteriorated. It is directly above.

The water flowing from the water supply connection port 1 is heated when passing through the lower header 2 and the heat absorbing water pipe 6 with the heat absorbing fins 5, and is stored in the upper header 4 by opening a faucet (not shown). Hot water is discharged from the hot water supply connection port 3. Combustion gas is B
As shown by the arrow, the heat absorbing fins 5 pass through the gaps of the heat absorbing water pipes 6 from the lower part to the upper part. In FIG. 3, the notches a and b absorb the dimensional change (increase) due to the thermal expansion of the fins by changing (decreasing) the width during combustion, so that the change in the position of the endothermic water pipe 6 is slightly suppressed. , The thermal stress on the connection between the upper and lower headers and the endothermic water pipe and the pipe wall of the endothermic water pipe is reduced.

The manufacturing method of the endothermic water pipe with the endothermic fins in the above-mentioned embodiment is possible with the same processing method and working time as the conventional product,
The function and effect can be provided easily and at low cost.

(Effect) Therefore, since the present invention has the above-mentioned configuration, the Cu of FIG.
Since the thermal stress generated as shown by the S-N curve in Fig. 1 is reduced to about half that in the conventional case, damage to the heat exchanger does not occur even if the ON / OFF combustion is repeated 1,000,000 times.

[Brief description of drawings]

FIG. 1 is an overall explanatory view showing an embodiment of the present invention, FIG. 2 is a plan view showing an embodiment of the present invention, and FIG. 3 is an AA of FIG.
Sectional drawing, FIG. 4 is an explanatory view showing the effect, FIG. 5 is a plan view showing a conventional embodiment, and FIG. 6 is a sectional view taken along line CC of FIG. DESCRIPTION OF SYMBOLS 1 ... Water supply connection port, 2 ... Lower header 3 ... Hot water supply connection port, 4 ... Upper header 5 ... Endothermic fins 5a ... Endothermic fins 6 ... Endothermic water pipes 7 ... Instant heat storage type water heat exchanger 8 ... Petroleum Burner, 9 ... Combustion chamber a ... Notch, b ... Notch

Claims (1)

[Scope of utility model registration request] 1. A plurality of endothermic fins of a single plate body are penetrated by a plurality of endothermic water pipes, and a lower header having a water supply connection port at one end of the endothermic water pipe is connected to an upper header having a hot water supply connection port at the other end. In this heat exchanger, a plurality of the endothermic water pipes are arranged only in the horizontal direction, a cutout portion is provided upward from the lower end of the endothermic fin between the endothermic water pipe and the endothermic water pipe, and from the upper end of the endothermic fin directly above the endothermic water pipe. A heat exchanger for a momentary hot water storage type hot water supply device, characterized in that a notch is provided up to the vicinity of the endothermic water pipe.