JPS6231814Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a hot water supply device used, for example, in a hot water heater or a gas water heater.

In general, for high-efficiency gas appliances, especially those with a thermal efficiency of 70 to 80% such as hot water supply equipment, when a large amount of cold water flows through the heat exchanger, the surface of the heat exchanger will become cold. easy to become When the surface of a heat exchanger becomes cold, moisture contained in the air or combustion gas that comes into contact with the surface of the heat exchanger condenses, often resulting in dew condensation on the surface of the heat exchanger. Moisture that has condensed on the surface of the heat exchanger becomes weakly acidic due to a chemical reaction with the combustion gas, corroding the fins of the heat exchanger, reducing the durability of the heat exchanger, and causing damage to the combustion parts of gas burners, etc. Corrosive substances may fall and clog the combustion section, and in such a case, the combustion gas may cause incomplete combustion.

By the way, to eliminate this problem,
Conventionally, a bypass pipe is connected between a water supply pipe that supplies water to a heat exchanger and a hot water outlet pipe that draws hot water from the heat exchanger, and a portion of the water flowing through the water supply pipe flows out to the bypass pipe. By doing so, the amount of cold water flowing through the heat exchanger was reduced, thereby preventing the temperature drop on the surface of the heat exchanger. However, the flow rate of the water flowing into the bypass pipe was arbitrarily set, for example, manually, resulting in poor reliability.Furthermore, the flow rate of water flowing into the bypass pipe was increased more than necessary, reducing the thermal efficiency of the entire device. There was also the problem of

This invention was made based on the above-mentioned circumstances, and its purpose is to provide a highly reliable hot water supply device which can reliably prevent condensation on the heat exchanger, thereby improving the durability of the heat exchanger and preventing incomplete combustion in the combustion section, and which can further increase the overall thermal efficiency.

This invention will be described below with reference to an embodiment shown in the drawings. The figure shows a hot water supply device for a hot water heater, and numeral 1 in the figure is a combustion tube. This combustion tube 1
A heat exchanger 2 is installed inside. This heat exchanger 2 has a large number of fins 2b arranged in parallel on the surface of a pipe 2a, the water supply part of this heat exchanger 2 is connected to one end of the water supply pipe 3, and the hot water supply part is connected to the water supply pipe 4. is connected to one end of the The other ends of the water supply pipe 3 and hot water outlet pipe 4 are each connected to a radiator (not shown) to form a hot water circulation circuit for heating. For example, cold water is supplied to the heat exchanger 2 through the water supply pipe 3 by a circulation pump (not shown), and hot water heated by the heat exchanger 2 is supplied to the radiator through the hot water outlet pipe 4, and the radiator heats the room. It is becoming more and more common. A gas burner (combustion section) 5 is arranged below the heat exchanger 2. This gas burner 5 is supplied with gas from a gas nozzle 7 attached to a flexible gas pipe 6, and is ignited by an appropriate ignition means. Also,
A temperature detector 8 is attached to the upper end of the combustion tube 1. This temperature detector 8 is located above the heat exchanger 2, and is designed to detect the temperature of the exhaust gas from the gas burner 5 that heated the heat exchanger 2. The temperature of this exhaust gas is generally low when the amount of gas supplied to the gas burner 5 is small, and also low when the flow rate of water flowing into the heat exchanger 2 is large.

On the other hand, a bypass pipe 9 is connected between the water supply pipe 3 and the hot water outlet pipe 4. A flow rate control valve 10 for adjusting the flow rate of water flowing out from the water supply pipe 3 into the bypass pipe 9 is installed at the connecting portion between the bypass pipe 9 and the water supply pipe 3. This flow rate regulating valve 10 includes, for example, a valve body 10a and a drive unit 10 such as a coil.
The valve body 10a is driven in proportion to the amount of electricity supplied to the drive unit 10b, that is, the opening degree of the valve 10 is controlled.
The drive section 10b is connected to a control means 11. Further, this control means 11 is connected to the temperature detector 8.
It is connected to the. This control means 11 controls opening and closing of the flow rate regulating valve 10 according to the temperature of the exhaust gas detected by the temperature detector 8, and maintains the heat exchanger 2 in a state where it is always heated to a predetermined temperature or higher. It is something to do. That is, the temperature of the exhaust gas is set in advance to such an extent that no condensation occurs in the heat exchanger 2, and when the temperature of the exhaust gas detected by the temperature detector 8 is higher than the set temperature, the flow rate regulating valve 10 The flow rate of water supplied into the heat exchanger 2 is increased by decreasing the opening degree of the flow rate regulating valve 10, and when the temperature of the exhaust gas detected by the temperature detector 8 is lower than the set temperature, the flow rate regulating valve 10 By increasing the opening degree and reducing the amount of water supplied into the heat exchanger 2, the heat exchanger 2 can be maintained at a constant temperature at which condensation does not occur. There is.

Therefore, when this apparatus having the above configuration is used, cold water is first supplied into the heat exchanger 2 from the water supply pipe 3 by a circulation pump or the like (not shown). This heat exchanger 2 is heated by a gas burner 5 and heats the cold water sent therein. At this time, the temperature sensor 8
The temperature of the exhaust gas is detected, and if the detected temperature is higher than the set temperature, the control means 11 controls the opening degree of the flow rate regulating valve 10 to be small, and the exhaust gas is supplied into the heat exchanger 2. By increasing the flow rate of cold water, thermal efficiency is increased. Also,
When the detected temperature is lower than the set temperature, the control means 11 controls the opening of the flow rate regulating valve 10 to increase the flow rate of the cold water supplied into the heat exchanger 2, thereby reducing heat. The occurrence of dew condensation on the surface of the exchanger 2 is reliably prevented. Further, the hot water heated by the heat exchanger 2 is mixed with the water sent through the bypass pipe 9 and sent to the radiator. After the room is heated by this radiator, the water is cooled by heat exchange with the indoor air and is sent into the water supply pipe 3 again.

Thus, in the case of the above structure, by appropriately controlling the opening degree of the flow control valve 10 according to the exhaust gas temperature and adjusting the flow rate of water flowing out from the water supply pipe 3 into the bypass pipe 9, Since the flow rate of water flowing through the heat exchanger 2 is variably controlled as appropriate, the heat exchanger 2 always maintains a relatively constant, relatively constant flow rate no matter what the combustion state of the gas burner 5 is. held at high temperature. Therefore, no dew condensation occurs on the surface of the heat exchanger 2,
Therefore, the fins of the heat exchanger are not corroded as in the conventional case, so the durability of the heat exchanger can be improved, and incomplete combustion of combustion gas can be prevented. moreover,
When the exhaust gas temperature is high, the opening degree of the flow control valve 10 can be reduced to increase the flow rate of cold water supplied into the heat exchanger 2, thereby improving overall thermal efficiency. .

Note that this invention is not limited to the above embodiments. For example, the flow rate control valve 10 does not necessarily need to be provided at the connection between the bypass pipe 9 and the water supply pipe 3, and may be provided at any position within the bypass pipe 9. Further, in the above embodiment, the case where the present device is used in a hot water heater is shown, but it goes without saying that it can also be used in a gas water heater or the like.

As explained above, according to this invention, a temperature detector is provided to detect the temperature of exhaust gas generated by combustion in the combustion section, and a water supply pipe that supplies cold water into the heat exchanger and hot water from the heat exchanger are provided. A bypass pipe is connected between a hot water tap pipe that sends out hot water, and a flow rate control valve that adjusts the flow rate of water flowing from the water supply pipe into the bypass pipe is variably controlled by a control means according to the temperature of the exhaust gas. As a result, the heat exchanger can always be kept heated at a relatively constant and relatively high temperature, which reliably prevents condensation on the heat exchanger and increases the durability of the heat exchanger. It is possible to provide a highly reliable hot water supply device that can improve the heat efficiency, prevent incomplete combustion in the combustion section, and further improve the overall thermal efficiency.

[Brief explanation of the drawing]

The figure is a schematic diagram of the main parts of an embodiment of this invention. 2... Heat exchanger, 3... Water supply pipe, 4... Hot water outlet pipe, 5... Gas burner (combustion part), 8... Temperature detector, 9... Bypass pipe, 10... Flow rate control valve,
11... Control means.

Claims (1)

[Scope of utility model registration request] A heat exchanger in which the water supply part is connected to the water supply pipe and the hot water outlet part is connected to the hot water outlet pipe, a combustion part that heats this heat exchanger, and a temperature that detects the temperature of exhaust gas generated by combustion in this combustion part. a detector, a bypass pipe whose one end is connected to the water supply pipe and whose other end is connected to the hot water outlet pipe, and a flow rate control valve that adjusts the flow rate of water flowing out from the water supply pipe into the bypass pipe. , connected to the temperature detector and controlling the flow rate adjustment valve to maintain the heat exchanger in a state where the heat exchanger is always heated to a predetermined temperature or higher according to the temperature of the exhaust gas detected by the temperature detector. A hot water supply device characterized by comprising a control means.