JPH06193970A - Hot water supplying heat exchanger - Google Patents

Abstract

PURPOSE:To provide a hot water supplying heat exchanger in which adherence of condensed water to a tube with fins for water-cooling flame is small and hence corrosion scarcely occurs with high durability. CONSTITUTION:A hot water supplying heat exchanger has a heat exchanging tube 3 with fins disposed above a flame generator F in a burning boiler 1 to heat water from an input water tube 4 via the tube 3 and to then output hot water to an output hot water tube 5, and comprises a second tube 6 with fins passed through the generator F in the boiler 1 via a plurality of switching valves 8, 9, 10 of parallel disposition having different flow rates branched from a midway of the tube 5. The plurality of the valves 8, 9, 10 are divided at open areas according to the degree of hot water set temperature and so formed as to be opened in a higher set temperature, the more the valves having larger passing flow rate are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water heat exchanger, and more particularly to a water cooling type low NOx combustion hot water heat exchanger.

[0002]

2. Description of the Related Art Conventionally, for example, when the Bunsen combustion system is used for combustion in a combustion can of a water heater, it is caused by combustion.
In order to reduce the NOx concentration, a structure in which a water pipe is passed through the flame is provided as one of means for lowering the flame temperature.

[0003]

However, when a finned pipe or the like for water cooling is passed through the flame, condensed water easily adheres to the finned pipe or the fins, which causes corrosion of the finned pipe or the like. There is a drawback that it is easy to be done and the life is shortened.

Therefore, the present invention is based on the above conventional water-cooled low NOx.
It is an object of the present invention to eliminate the drawbacks of a hot water supply heat exchanger for combustion and to provide a hot water supply heat exchanger that has less adhesion of condensed water to a flame water cooling finned tube and is therefore less likely to corrode.

[0005]

In order to achieve the above object, the hot water heat exchanger of the present invention has a heat exchange finned pipe arranged above the flame generating portion in the combustion can body, and is connected to the water inlet pipe. A heat exchanger for hot water supply, which heats the water through the pipe with fins for heat exchange and then discharges the hot water into a hot water discharge pipe, wherein a plurality of parallel arrangements of different passage flow rates are provided from the middle of the hot water discharge pipe. The second finned pipe that passes through the flame generating part in the combustion can is branched via the on-off valve, and the plurality of parallel-arranged on-off valves have open / closed regions in which the set hot water temperature is high or low. It is characterized in that it is configured such that the opening / closing valve that is divided by and has a larger passing flow rate is opened in the high temperature set temperature region.

[0006]

According to the above feature of the present invention, during the hot water supply operation, a part of the hot water flowing through the hot water outlet pipe flows into the second finned pipe to cool the combustion flame and suppress the generation of NOx.
Among the plurality of on-off valves arranged in parallel, the on-off valve with a large passage flow rate is opened when the hot water supply set temperature is high, and the on-off valve with a small passage flow rate is opened when the hot water supply set temperature is low. It will be released. Therefore, when the hot water supply set temperature is high, the flow rate of hot water flowing to the second finned pipe is large, and when the hot water supply set temperature is low, the flow rate of hot water flowing to the second finned pipe is small, and as a result, regardless of the hot water supply set temperature. The temperature of the hot water flowing through the second finned tube is stabilized at an appropriate temperature.
Therefore, the temperature of the second finned tube itself can be stabilized to a temperature at which condensed water does not easily adhere, corrosion of the second finned tube is suppressed, and durability is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of an embodiment of the present invention.
A Bunsen combustion burner 2 is provided in the combustion can body 1. In addition, an instantaneous heat exchange finned tube 3 made of copper is provided in the upper portion of the combustion can body 1. A water inlet pipe 4 is externally connected to the heat exchange finned pipe 3, and hot water heated by the heat exchange finned pipe 3 is discharged to a hot water discharge pipe 5.

A pipe 6 with a second fin 6a made of copper is branched from the middle of the hot water discharge pipe 5, and the burner 2 inside the combustion can body 1 is branched.
After coming out of the can body 1 through the flame generating part F by the above, it joins again with the outlet pipe 5 on the downstream side through the Venturi pipe 7. The second finned pipe 6 is branched from the hot water discharge pipe 5 through three on-off valves 8, 9 and 10 arranged in parallel in this embodiment. This on-off valve 8,
9 and 10 are composed of a high temperature on-off valve 8, a medium temperature on-off valve 9 and a low temperature on-off valve 10 which open respectively in three temperature regions depending on the level of the hot water supply set temperature. The control unit 11 is configured to control the opening and the passing flow rate at the time of opening is set to a large flow rate. The low-temperature on-off valve 10 is configured to be opened by the control unit 11 in a low-temperature hot water supply set temperature region below a certain level, and is configured to have a small flow rate when opened. The medium temperature on-off valve 9 is configured to be opened by the control unit 11 in a temperature region intermediate between the high temperature and low temperature hot water supply set temperature regions, and the passage flow rate at the time of opening is configured to be a medium flow rate. There is.

Now, when the hot water supply temperature is set by a remote controller or the like (not shown) and the hot water supply is started by opening the currant at the end (not shown) of the hot water outlet pipe 5, the water from the water inlet pipe 4 comes with heat exchange fins. It is sent to the pipe 3 and heated to a predetermined hot water supply set temperature, and is discharged to the hot water discharge pipe 5. When the hot water supply set temperature is in a high temperature region above a predetermined constant temperature, the high temperature on-off valve 8 is opened via the control unit 11, and a large amount of hot water flows into the second finned pipe 6. Further, when the hot water supply set temperature is in a low temperature region below a predetermined constant temperature, the low temperature on-off valve 10 is opened via the control unit 11 and a small amount of hot water flows into the second finned pipe 6. Further, when the hot water supply set temperature is in the intermediate temperature range, the medium temperature on-off valve 9 is opened via the control unit 11, and a medium flow rate of warm water flows into the second finned pipe 6.

By flowing hot water in the second finned pipe 6, the combustion flame F of the burner 2 is cooled, and the NOx emission amount is reduced. Further, the temperature of the hot water flowing in the second finned pipe 6 can be a stable temperature without being affected by the hot water outlet temperature by taking into consideration the relationship between the hot water supply set temperature and the flow rate. That is, at least the second finned tube 6
Can be prevented from becoming a low temperature, and it is possible to stabilize the temperature at which condensed water does not easily adhere, for example, to a high temperature of 50 ° C. or higher, and corrosion of the second finned pipe 6 is suppressed.

[0011]

The present invention has the above-described structure and operation. According to the heat exchanger for hot water supply according to claim 1, a plurality of on-off valves arranged in parallel, each having a different flow rate from the middle of the tap pipe, are provided. Via the second finned tube passing through the flame generating part in the combustion can via the plurality of parallel-arranged on-off valves, each open region is divided according to the hot water supply temperature setting. In addition, since the opening / closing valve with a larger flow rate is opened in the high temperature set temperature range, the temperature of the hot water flowing in the second finned pipe is stabilized without being affected by the height of the hot water supply set temperature. Therefore, the temperature of the second finned tube itself can be stabilized to a temperature at which condensed water does not easily adhere, and durability can be improved by suppressing corrosion. Of course, the NOx emission concentration can be reduced by cooling the flame with the second finned tube.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Combustion can 2 Bunsen combustion burner 3 Heat exchange finned pipe 4 Water inlet pipe 5 Hot water outlet pipe 6 Second finned pipe 8 High temperature open / close valve 9 Medium temperature open / close valve 10 Low temperature open / close valve F Flame generation part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Shimazu, 32 Akashi-cho, Chuo-ku, Kobe-shi, Hyogo In stock company Noritsu (72) Inventor Satoshi Kawaguchi 32 Akashi-cho, Chuo-ku, Kobe-shi, Hyogo Noritsu Co., Ltd. Within

Claims (1)

[Claims] 1. A heat exchange finned pipe is arranged above a flame generation part in a combustion can, and water from a water inlet pipe is heated through the heat exchange finned pipe and then tapped into a hot water outlet pipe. A heat exchanger for hot water supply with a second fin passing through a flame generating part in the combustion can body through a plurality of parallel-arranged on-off valves each having a different flow rate from the middle of the hot water discharge pipe. The opening and closing valves that branch the pipe and are arranged in parallel are divided into open and closed areas according to the hot water supply set temperature, and the open and closed valves with a larger passing flow rate open in the high temperature set temperature area. A heat exchanger for hot water supply, characterized in that