JPS6146740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a water heater equipped with a double-pipe heat exchanger, and its purpose is to prevent the heat exchanger performance from decreasing even when the flow rate is small.

As shown in Figure 1, the conventional water heater of this type has the following features:
A part of the heating system A, in which a heating means 2 is added to a circulation loop a with a pump 1 interposed therebetween, is passed through a water supply pipe 5 having a water supply port 3 and a stop valve 4 to form a double pipe heat exchanger section b. With this configuration, open the stop valve 4 and let the water flow through the double pipe heat exchanger section b.
Since the hot water is extracted by extracting heat from the high temperature fluid circulated by the pump 1, there is a drawback that the performance of the double pipe heat exchanger decreases when the amount of hot water discharged is reduced. In other words, the amount of heat acquired QKCal/γ is obtained by the following formula: Q=K・F・△tm ………(1) K: Heat transfer coefficient KCal/γ F: Heat transfer area m ² △tm: Logarithmic mean temperature difference °C The heat transmission coefficient K is expressed by the following formula.

1/K = (1/α) + (δ/λ) + (1/α) α: Heat transfer coefficient on the fluid side δ/λ: Heat exchanger plate thickness/thermal conductivity (pipe material) α: Fluid side Heat Transfer Coefficient If we assume the fluid on the exit side, α depends on the flow velocity, so α → becomes small, and even if α is large, K will be a small value. Therefore, in order to obtain a predetermined amount of heat at a small flow rate, the amount of heat Q obtained becomes small, and the heat transfer area of the heat exchanger must be increased, which increases the manufacturing cost and increases the size. In view of this point, the present invention replaces a part of the heating circulation loop that circulates the hot water pump heated by the heating means with a part of the circulation loop of the hot water supply system path that forms the circulation loop by the pump between the water supply pipe and the hot water outlet pipe. A double-tube heat exchanger section is formed through the tube to prevent the heat exchanger performance from decreasing even when the flow rate is small.

The present invention will be explained below based on the embodiment shown in the second figure. a heating system path A in which a heating means 12 such as a heating wire is added to a circulation loop I with a pump 11 interposed;
Hot water outlet pipe 1 having a water supply pipe 13 and a stop valve b
A part 16 of the circulation loop of the heating system A is connected to a part 1 of the circulation loop of the hot water supply system B with a pump 15 interposed therebetween to form a circulation loop.
7 to form a double-pipe heat exchanger section H, and the heating system path A and hot water supply system path B are combined to form a hot water supply device.

Open the stop valve b of the water heater with the above configuration and replace changes in water flow, water pressure, etc. with signals to pump 11.
When 15 and 15 are operated, the supplied water flows into the circulation loop via the water supply pipe 13, and as it circulates through this circulation loop by the action of the pump 15, it is given heat by the double pipe heat exchanger section H, and the amount of hot water is increased by the amount of hot water produced. At this time, the amount of fluid flowing through the double-pipe heat exchanger section, that is, the fluid velocity, is equal to the amount of water passing through the pump 15 minus the amount of hot water, so even if the amount of hot water is reduced, the double-pipe heat exchanger will still work. There is no change in the amount of fluid flowing through the vessel, and the amount of heat acquired by the circulation loop is always constant, and is not affected by the amount of hot water dispensed.

According to the present invention, it is possible to design a compact water heater that can obtain a large amount of exchanged heat even when the amount of hot water supplied is small, and the flow rate in the heat exchanger is increased, so that it is possible to prevent dirt from adhering to the circulation loop. Also, since the hot water is supplied by a pump, it is possible to provide stable hot water supply even when the water supply pressure is low.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing a conventional example, and FIG. 2 is a system configuration diagram showing an embodiment of the present invention. Symbol explanation of the main parts, , is a circular loop,
11 and 15 are pumps, 12 is a heating means, A is a heating system path, b is a stop valve, B is a hot water supply system path, and H is a double pipe heat exchanger section.

Claims (1)

[Claims] 1 A part of the heating circulation loop in which hot water heated by the heating means is circulated by a pump is penetrated into a part of the circulation loop of the hot water supply system line, which forms a circulation loop by the pump between the water supply pipe and the hot water outlet pipe, resulting in a double pipe system. A water heater characterized by forming a heat exchanger section.