WO2003033969A1

WO2003033969A1 - Boiler and heat accumulation tank for boiler

Info

Publication number: WO2003033969A1
Application number: PCT/KR2002/001619
Authority: WO
Inventors: Young-Hwan Choi; Jin-Min Choi
Original assignee: Young-Hwan Choi; Jin-Min Choi
Priority date: 2001-10-17
Filing date: 2002-08-28
Publication date: 2003-04-24

Abstract

A boiler ensures water above a predetermined temperature to be introduced into its main heat exchanger, thereby preventing a phenomenon of either dewing or efflorescence. The boiler comprises: a heat accumulation tank containing room-heating water; a first section for heating the room-heating water discharged from the accumulation tank before returning the room-heating water to the accumulation tank; a second section for circulating the room-heating water from the accumulation tank through a heating-requiring space back to the accumulation tank; a third section for supplying hot water, the third section including a water-introduction port connected with a source of water-supply, a water-discharge port through which the hot water is discharged, and a heat transmission section disposed in the heat accumulation tank and having a tubular member connecting the water-introduction port and the water-discharge port with each other; and a control section for controlling operation of the first means according to the temperature of the room-heating water in the heat accumulation tank and for controlling operation of the second means according to whether the boiler is in a room heating mode or not.

Description

BOILER AND HEAT ACCUMULATION TANK FOR BOILER

TECHNICAL FIELD

The present invention relates generally to a boiler and a heat accumulation tank for boiler, and more particularly to a boiler, in which a heat accumulation tank is provided therein, so that the a room-heating water heated by and introduced from a main heat exchanger is stored in the heat accumulation tank, whereby the stored room-heating water is supplied to a heating pipe disposed in a space which requires heating while being used as a heat supply source of the boiler during generating of hot water and a heat accumulation tank for boiler.

BACKGROUND ART

Generally, hot water for bathing and room-heating water, that are required in home, are generated and supplied through a boiler. Fig. 1 shows a structure of a home boiler according to an embodiment of the prior art.

As shown in Fig. 1, the prior boiler includes a burner 101 which is disposed within a case of a given shape shown by a dotted line and which serves as a heat source for the boiler. Above the burner 101, a main heat exchanger 102 is located, which comprises tubes having heat radiation pins formed on an outer surface of a pipe and serving to convert cold water into hot water. Also, the boiler includes an open type expansion tank 103 which is connected to one end of a heating pipe 107 extended by way of the main heat exchanger 102. Moreover, the boiler includes a circulation pump 104 disposed in the pipe 107. Furthermore, the boiler comprises a three-way valve 105 which is disposed in the pipe 107 and serves to control the flow direction of influent water. In addition, the boiler includes a plate type heat exchanger 106, which is connected with the three-way valve 105; cold and hot water pipes 108 and 108' which are connected to the plate type heat exchanger 106 and to which a flow sensor 111 is attached; a control panel 109 serving to control the operation of the boiler; and a fuel supply pipe 110 for supplying fuel to the burner 101.

Accordingly, when a user turns on a heating switch (not shown) disposed in a room for the heating of a room, the exit of the three-way valve 105 to the plate type heat exchanger 106 is closed in response to a signal transmitted to the control panel 109 while the exit of the valve 105 to a hot water supply pipe 107a is opened. The circulation pump 104 is operated while the burner 101 is operated, so that fuel supplied from the fuel supply pipe 110 is combusted to generate heat. The generated heat functions to heat water which is flowed into the heating pipe 107 through the main heat exchanger 102. The heated water is discharged by way of the three-way valve 105 to the hot water supply pipe 107a. The hot water supply pipe 107a is connected to one end of a heating pipe (not shown) disposed in a space which requires heating, so that the heated water passes through the hot water pipe and returns through a hot water return pipe 107b to the main heat exchanger 102.

Meanwhile, the open type expansion tank 103 is employed in storing the overflow hot water. On the other hand, when a user turns on a tap in order to use hot water, an inflow of cold water is perceived by a flow sensor 111 disposed on the cold water pipe 108. When a signal from the flow sensor 111 is transmitted to the control panel 109, the exit of the three-way valve 105 to the hot water supply pipe 107a is closed while the exit of the valve 105 to the plate type heat exchanger 106 is opened and the circulating pump 104 and the burner 101 are operated. The heated water is passed through the plate type heat exchanger 106 via the three-way valve 1Q5. At this time, heat exchange is carried out between the heated water and the cold water introduced from the cold water pipe 108 and passing through the plate type heat exchanger 106 in the plate type heat exchanger 106, thereby the cold water is converted into hot water and the converted hot water is discharged through the hot water pipe 108' .

In the prior boiler, however, since the temperature of the water introduced into the main heat exchanger in the early operation of the boiler is low, dewing of water occurs on outer surfaces of the pin tubes of the main heat exchanger, whereby an efflorescence phenomenon is created. That is, in the early operation of the boiler, the temperature of the cold water introduced into the pin tubes is as low as about 14 °C. When high temperature heat (600 °C) of the burner is applied to the surfaces of the pin tubes, dewing of the water occurs on the pin tubes of the main heat exchanger. The dewing water is easily combined with exhaust gas such as carbonic acid gas, sulfuric acid and nitrogen oxide, during the burning of the boiler. When the combination between the dewing water and the exhaust gas is repeated, efflorescence phenomenon occurs in which white fixing material is formed on the outer surfaces of the pin tubes of the main heat exchanger in layers, therefore the heat exchange capacity of the main heat exchanger is remarkably reduced.

Also, in the prior boiler as shown in FIG.l, there is a defect in that the lower the present temperature of the hot water or the room-heating water is, the more time it takes to be reached at a desired temperature. In order to make up for the defects, there is an applied proportional control technology in which the amount of the air or the fuel injected to the burner increases in proportion to a increase in the difference between the present temperature and the desired temperature. However, to implement the proportional control technology, since it is necessary to develop structural elements such as a sensor or a control circuit, the cost of production becomes higher.

Also, the plate type heat exchanger employed in the prior boiler is complicated in its structure and has difficulty in manufacturing, so that its productivity is deteriorated.

Fig. 2 shows a structure of a boiler according to another embodiment of the prior art . As shown in FIG. 2, the boiler which comprises of a separate hot water storage tank 132 disposed outside of the body thereof in order to prevent cold water of 14 °C from being supplied directly to the pin tubes of the main heat exchanger 122 is provided. Within the hot water storage tank 112 is disposed a heating pipe 133. Water in the hot water storage tank 132 is heated with hot water supplied through the heating pipe 133 from the main heat exchanger 122. The heated water is supplied as hot water for bathing, etc. through hot water supply pipes 134 connected to one side of the hot water storage tank 132. In the meantime, in a room heating mode, the room- heating water is supplied through hot water supply pipes 127a, which is diverged from a distributor 135, by way of a three-way valve 125 to a heating pipe (not shown) disposed in a space which requires heating and returns through a hot water return pipe 127b to the main heat exchanger 122.

The boiler as shown in FIG. 2 has the problems of the dewing phenomenon and the efflorescence phenomenon as before. That is, in a case that the boiler is not operated for a given period (above about 10 hours) in the winter season, the room-heating water becomes cool, below 14 °C. At this time, when it turns on the boiler, as cold water below 14 °C is also flowed directly into the main heat exchanger 122, the dewing phenomenon, thus the efflorescence phenomenon cannot be prevented.

Also, the hot water storage tank connected with a source of water-supply to home must endure the predetermined pressure from the source of water-supply, so that there is difficulty in changing of shapes and sizes thereof.

Moreover, since the three-way valve in the conventional boiler has many components and a complicated construction, such problems as frequent troubles of the three-way valve or water-leakage are generated, with the passage of a predetermined time, thereby making it difficult to maintain and manage the boiler. DISCLOSURE OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a boiler, in which a heat accumulation tank capable of storing the hot water heated by and introduced from a main heat exchanger is disposed in a case of the boiler and which enables a room-heating water above a predetermined temperature to be introduced into its main heat exchanger, thereby preventing a phenomenon of either dewing or efflorescence.

It is another object of the present invention to provide a boiler having a superior capability in instantly supplying hot water.

It is further, another object of the present invention used to provide a boiler capable of simplifying its construction and cutting down manufacturing costs of the boiler.

It is further another object of the present invention to provide a heat accumulation tank for storing a room-heating water which is disposed in the boiler and which possesses good characteristics in heat exchange for generating hot water.

To accomplish this object, the present invention provides a boiler, which comprises: a heat accumulation tank containing room-heating water; a first means for heating the room-heating water discharged from the accumulation tank before returning the room-heating water to the accumulation tank; a second means for circulating the room-heating water from the accumulation tank through a heating-requiring space back to the accumulation tank; a third means for supplying hot water, the third means including a water-introduction port connected with a source of water-supply, a water- discharge port through which the hot water is discharged, and a heat transmission section disposed in the heat accumulation tank having a tubular member connecting the water-introduction port and the water- discharge port with each other; and a control means for controlling the operation of the first means according to temperature of the room-heating water in the heat accumulation tank as well as for controlling the operation of the second means according to whether the boiler is in a room heating mode or not.

According to the boiler of the present invention, the first means comprises a main heat exchanger having an entrance port and an exit port, the entrance port being connected with a first discharge tube formed at the accumulation tank, the exit port being connected with a first introduction tube formed at the accumulation tank; a burner for supplying heat to the main heat exchanger; and a first circulation pump for circulating the room-heating water from the first discharge tube toward the first introduction tube.

According to the boiler of the present invention, the second means comprises of a heating pipe disposed in the heating-requiring space, the heating pipe having an entrance port and an exit port, the entrance port of the heating pipe being connected with a second discharge tube formed at the heat accumulation tank, the exit port of the heating pipe being connected with a second introduction tube formed at the heat accumulation tank; and a second circulation pump for circulating the room- heating water from the second discharge tube toward the second introduction tube . According to the boiler of the present invention, the first and second circulation pumps are capable of controlling the flow speed of the room-heating water.

According to the boiler of the present invention, the control means comprises a temperature sensor provided at the heat accumulation tank and a control panel that operates the first means when temperature detected by the temperature sensor is lower than a predetermined value, the control panel generates a signal for operating the second means when the boiler is in the room heating mode.

According to the boiler of the present invention, the boiler further comprises an expansion tank communicating with the first means. According to the boiler of the present invention, the second means is operated when the boiler is in the room heating mode but is stopped when the boiler is in a hot bath mode .

To accomplish another object, the present invention provides a heat accumulation tank for containing room-heating water of a boiler, the heat accumulation tank comprising a first discharge tube through which the room-heating water contained in the .heat accumulation tank flows to a first means for heating the room-heating water; a first introduction tube, through which the room-heating water heated by the first means returns to the heat accumulation tank; a second discharge tube, through which the room-heating water contained in the heat accumulation tank flows to a second means for circulating the room-heating water; a second introduction tube, through which the room-heating water returns to the heat accumulation tank after being circulated through a heating-requiring space by the second means; and a third means for supplying hot water, the third means including a water-introduction port connected with a source of water-supply, a water- discharge port through which the hot water is discharged, and a heat transmission section disposed in the heat accumulation tank as well as having a tubular member connecting the water-introduction port and the water-discharge port with each other.

According to the heat accumulation tank of the present invention, the room-heating water is discharged through the first discharge tube from a lower portion of the heat accumulation tank and the room-heating water is introduced through the first introduction tube into an upper portion of the heat accumulation tank. Also, the room-heating water is discharged through the second discharge tube from an upper portion of the heat accumulation tank, and the room-heating water is introduced through the second introduction tube into a lower portion of the heat accumulation tank.

According to the heat accumulation tank of the present invention, the heat transmission section is arranged in a spiral shape.

According to the heat accumulation tank of the present invention, the first discharge tube is disposed above the heat accumulation tank, the heat transmission section is arranged in a spiral shape, and a suction tube extends downward from the first discharge tube and inside of the heat transmission section while a plurality of introduction holes are formed through a side of the suction tube.

According to the heat accumulation tank of the present invention, each of the introduction holes has a flange protruding outward in a tubular shape.

According to the heat accumulation tank of the present invention, the introduction holes have diameters which increase as locations of the introduction holes become lower. Also, the introduction holes are oriented in a direction opposite to a side to which the room- heating water heated in the main heat exchanger returns through the first introduction tube.

According to the heat accumulation tank of the present invention, the introduction holes are formed through an upper portion of the suction tube, an outer suction tube is disposed surrounding the suction tube while a plurality of outer introduction holes are formed through a lower portion of the outer suction tube, and the heat transmission section is arranged in a double- spiral shape, which includes inner and outer spiral sections, the inner spiral section being disposed between the suction tube and the outer suction tube, the outer spiral section being disposed between the outer suction tube and a body of the tank.

BRIEF DESCRIPTION OF THE DRAWINGS

The above as well as the other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view of a boiler according to an embodiment of the prior art; FIG. 2 is a schematic view of a boiler according to another embodiment of the prior art;

FIG. 3 is a schematic view of a boiler having a heat accumulation tank for storing the room-heating water according to an embodiment of the present invention;

FIG. 4 is a flow chart illustrating an embodiment of an operation of a boiler according to the present embodiment ; FIG. 5A is a sectional view of the heat accumulation tank according to the present invention;

FIG. 5B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 5A; FIG. 6A is a sectional view of a heat accumulation tank according to another embodiment of the present invention;

FIG. 6B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 6A; FIG. 7A is a sectional view of a heat accumulation tank according to another embodiment of the present invention;

FIG. 7B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 7A; and

FIG. 7C is a perspective view of an outer suction tube disposed in the heat accumulation tank shown in FIG. 7A.

Best Mode for Carrying Out the Invention

Reference will now be made in detail to the preferred embodiments of the present invention.

In the following description, "room-heating water" means water used in room heating, and "hot water" means water used for other purposes than room heating, such as bathing or cleaning.

FIG. 3 is a schematic view of a boiler having a heat accumulation tank for storing the room-heating water according to an embodiment of the present invention, a case of which is shown by a broken line.

The boiler according to the present embodiment includes a burner 11 for receiving fuel through a fuel supply tube 14 and providing heat, a main heat exchanger 12 for heating water circulating in the main heat exchanger 12 by means of the heat generated by the burner 11, and a heating pipe (not shown) disposed in a region or space which requires heating.

Further, the boiler according to the present embodiment includes a heat accumulation tank 1 capable of storing the hot water heated by and introduced from the main heat exchanger 12, which is disposed in the case of the boiler.

The heat accumulation tank 1 includes a first discharge tube 3a, through which the room-heating water contained in the heat accumulation tank 1 is introduced into the main heat exchanger 12 to be heated, a first introduction tube 3b, through which the room-heating water heated by the main heat exchanger 12 returns to the heat accumulation tank 1, a second discharge tube 5a, through which the room-heating water contained in the heat accumulation tank 1 is introduced into the heating pipe for heating, and a second introduction tube 5b, through which the room-heating water returns from the heating pipe to the heat accumulation tank 1.

The first discharge tube 3a, one end of which extends to and is connected with a lower portion of the heat accumulation tank 1, is provided with an internal circulation pump 4. The other end of the first discharge tube 3a is connected with an entrance port of the main heat exchanger 12. One end of the first introduction tube 3b is connected with an exit port of the main heat exchanger 12, and the other end of the first introduction tube 3b is connected with an upper end of the heat accumulation tank 1. By this construction, when the internal circulation pump 4 is operated, the room- heating water at a lower portion of the heat accumulation tank 1 flows through the main heat exchanger 12 while being heated, and then returns to an upper portion of the heat accumulation tank 1. The second discharge tube 5a, one end of which is connected with the upper portion of the heat accumulation tank 1, is provided with a heating-water circulation pump 7. The other end of the second discharge tube 5a is connected with an entrance port of the heating pipe (not shown) disposed in the space which requires heating. One end of the second introduction tube 5b is connected with an exit port of the heating pipe, and the other end of the second introduction tube 5b is connected with a lower end of the heat accumulation tank 1. When the heating-water circulation pump 7 is operated, the room-heating water at the upper portion of the heat accumulation tank 1 flows through the heating pipe while transmitting heat to the heat- requiring space, and then returns to the lower portion of the heat accumulation tank 1.

The internal circulation pump 4 and the heating- water circulation pump 7 described above each is provided with a motor, which utilizes electric power of a direct or alternating current and can control its rotational speed, thereby being capable of controlling the speed of the water flowing through the first discharge tube 3a and the second discharge tube 5a. The internal circulation pump 4 and the heating-water circulation pump 7 are electrically connected with a control panel 13 which will be described later in detail .

Further, the heat accumulation tank 1 contains a temperature sensor 10 for detecting temperature of the room-heating water, which is electrically connected with the control panel 13 which will be described later.

The first discharge tube 3a communicates with an expansion tank 8, so that the first discharge tube 3a contains over-expanded hot water. The expansion tank 8 has a drain tube 8a, through which water is drained when level of the water is too high, and a water-level sensor 9 for sensing the lever of the water.

A hot water pipe 2 extending in a spiral shape is disposed in the heat accumulation tank 1. A water- introduction port 2a and a water-discharge port 2b are formed at opposite ends of the hot water pipe 2. The water-introduction port 2a is connected with a source of water-supply to home, and the water-discharge port 2b is connected with a water tap or a shower faucet . The hot water pipe 2 is made from nonferrous metal and has a heat transmission section having a spiral shape. The heat transmission section having a spiral shape can contain a considerable quantity of water. The temperature of the water contained in the heat transmission section is maintained always above a predetermined temperature by the heat transmitted from the room-heating water contained in the heat accumulation tank 1. Therefore, when a user wants to use hot water, hot water of at least the predetermined temperature can be supplied to the user without delay at any time. After the water supply is initiated, the water newly introduced through the water-introduction port 2a is heated to become hot water of high temperature through heat-exchange with the room-heating water of high temperature contained in the heat accumulation tank 1 while passing through the heat transmission section, and then is supplied to the user through the water- discharge port 2b.

Hereinafter, the operation of the boiler having the above-mentioned construction according to the present embodiment will be described with reference to FIGs . 3 and 4.

When a user turns on a switch disposed, for example, indoors, the switch sends a signal to the control panel 13 provided at the boiler, so as to turn on the boiler (step 21) . As soon as the boiler is turned on, a series of system examination steps from step 22 to step 30 are progressed, so as to examine and check for normal or abnormal operation of the boiler. This examination process includes labors of examining if there is leakage of gas or not and if it is necessary to complement water or not (steps 22 to 26) . Further, after the heating-water circulation pump 7 is operated for a predetermined period of time, a labor of examining the function of the system is performed (steps 27 to 30) .

When no problem is found in the above examination process, a boiler operation mode is initiated in step 31.

When the boiler is confirmed as being normally operated (step 32) , whether or not the boiler is presently in a hot bath mode is confirmed (step 33) .

In the case where the boiler is not in the hot bath mode, when the temperature of the room-heating water in the heat accumulation tank 1, which -is detected by the temperature sensor 10 provided at the heat accumulation tank 1, is lower than a predetermined lowest limit value, the internal circulation pump 4 and the burner 11 are operated to heat the room-heating water. In contrast, when the temperature of the room- heating water is higher than a predetermined highest limit value, the operation of the internal circulation pump 4 and the burner 11 is stopped. These operations and stoppages of the internal circulation pump 4 and the burner 11 are repeated, so as to maintain the temperature of the room-heating water in a specific range of temperature, in step 32. Further, the heating- water circulation pump 7 is operated to supply the room- heating water in the heat accumulation tank 1 to the heating pipe. In this case, since the room-heating water initially introduced through the second discharge tube 5a into the heating pipe is the water already stored in the heat accumulation tank 1, which means that the room- heating water has a temperature above a predetermined value, the room-heating water can immediately perform the room heating function. After performing the heating function, the room-heating water returns through the second introduction tube 5b to the heat accumulation tank 1.

In the course of the above procedure, when the temperature of the room-heating water is strikingly lower than the predetermined lowest limit value, the rotation of the motor of the internal circulation pump 4 is accelerated to increase the quantity of the room- heating water circulating through the main heat exchanger 12 and returning to the heat accumulation tank 1. In the opposite case, the rotation speed of the motor is reduced. Therefore, the room-heating water can be heated to a desired temperature in a shorter period of time. In step 33, if it is confirmed that the boiler is in the hot bath mode, the internal circulation pump 4 and the burner 11 are operated to maintain the room- heating water in the heat accumulation tank 1 at a predetermined temperature. However, the heating-water circulation pump 7 is not operated (step 35) . That is, when a user opens the water tap, the hot water (of about 0°C) contained in the hot water pipe 2 is supplied while new hot water is introduced through the water- introduction port 2a into the heat transmission section. Then, the newly introduced hot water is indirectly heated to a predetermined temperature through heat- exchange with the room-heating water while passing through the main heat exchanger 12, and then is supplied through the water-discharge port 2b. When all the operation of the boiler as described above has been completed, the boiler returns to its initial mode and comes to be in a waiting state (step 36) .

Hereinafter, a heat accumulation tank employed in a boiler according to the present invention will be described in detail with reference to the drawings.

The boiler according to the present invention includes a heat accumulation tank as shown in FIG. 3, which has a construction having an improved effect in transmitting heat from the room-heating water to a hot water pipe .

FIG. 5A is a sectional view of the heat accumulation tank according to the present embodiment, and FIG. 5B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 5A.

As shown, the first discharge tube 3a is disposed above the heat accumulation tank 1, and a suction tube 50 extends downward from the first discharge tube 3a and in the heat accumulation tank 1 so that the room-heating water in the heat accumulation tank 1 can be introduced through the suction tube 50 and the first discharge tube 3a into the main heat exchanger 12.

The heat transmission section of the hot water pipe 2 disposed in the heat accumulation tank 1 has a spiral shape, and the suction tube 50 is disposed in the transmission section.

A plurality of introduction holes 52 are formed through a side surface of the suction tube 50, so that the room-heating water in the heat accumulation tank 1 is introduced into the suction tube 50 through the introduction holes 52.

The introduction holes 52 are arranged vertically in the longitudinal direction of the suction tube 50. In this case, the lower the introduction hole 52 is located, the larger the diameter of the introduction hole 52 is. Further, the introduction holes 52 are oriented in a direction opposite to the side to which the room-heating water heated in the main heat exchanger 12 returns through the first introduction tube 3b. The room-heating water introduced through the first introduction tube 3b into the heat accumulation tank 1 transmits heat to the water contained in the heat transmission section of the hot water pipe 2, and then is introduced through the introduction holes 52 into the suction tube 50 and flows through the first discharge tube 3a to the main heat exchanger 12.

In this case, since the introduction holes 52 have different diameters, a smaller quantity of water is introduced into the suction tube 50 through the introduction holes 52 of smaller diameters at the upper portion of the heat accumulation tank 1 at which a large quantity of high-temperature room-heating water exists, while an increasing quantity of water at a decreasing temperature is introduced into the suction tube 50 through the introduction holes 52, which as specified above have increasing diameters as the locations of the introduction holes 52 become lower.

Therefore, the room-heating water introduced through the first introduction tube 3b can smoothly flow to a lower portion of the heat accumulation tank 1, so that heat exchange between the hot water pipe 2 and the room-heating water in the heat accumulation tank 1 can be effectively performed.

Further, since the introduction holes 52 formed through the suction tube 50 are oriented in a direction opposite to the side to which the room-heating water at a high temperature is introduced through the first introduction tube 3b, the introduced room-heating water is prevented from being directly introduced into the suction tube 50 without exchanging heat with the hot water pipe 2, so that more effective heat-exchange is carried out .

FIG. 6A is a sectional view of a heat accumulation tank according to another embodiment of the present invention, and FIG. 6B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 6A.

The accumulation tank according to the present embodiment has nearly the same construction as that according to the previous embodiment, excepting that each of introduction holes 54 formed through the suction tube 50 has a flange protruding outward in a tube shape.

The protruding flanges of the introduction holes 54 increase length of a fluid channel through which the room-heating water introduced through the first introduction tube 3b flows before being introduced into the suction tube 50, so as to enable the high- temperature room-heating water to circulate more distance in the heat accumulation tank 1 while being in contact with the hot water pipe 2, thereby improving efficiency in the heat exchange.

FIG. 7A is a sectional view of a heat accumulation tank according to another embodiment of the present invention, FIG. 7B is a perspective view of a suction tube disposed in the heat accumulation tank shown in FIG. 7A, and FIG. 7C is a perspective view of an outer suction tube disposed in the heat accumulation tank shown in FIG. 7A.

In the heat accumulation tank according to the present embodiment, a separate outer suction tube 60 is further disposed surrounding the suction tube 50, so that the high-temperature room-heating water introduced through the first introduction tube 3b can flow through a fluid channel of greater length while exchanging heat with the water contained in the hot water pipe 2. In order to achieve this construction, a plurality of introduction holes 56 are formed through an upper portion of the suction tube 50 and arranged in its circumferential direction, and a plurality of outer introduction holes 66 are formed through a lower portion of the outer suction tube 60 disposed outside of the suction tube 50.

Further, the hot water pipe 2 has a heat transmission section arranged in a double-spiral shape, which includes inner and outer spiral sections. The inner spiral section is disposed between the suction tube 50 and the outer suction tube 60, and the outer spiral section is disposed between the outer suction tube 60 and a body of the tank. By this construction, the high-temperature room- heating water introduced through the first introduction tube 3b first exchanges heat with the outer spiral section of the hot water pipe 2, and then passes through the outer introduction holes 66 into the outer suction tube 60. Thereafter, the room-heating water secondarily exchanges heat with the inner spiral section of the hot water pipe 2, and is introduced through the introduction holes 56 into the suction tube 50, and then flows through the first discharge tube 3a to the main heat exchanger 12.

As a result, the length of the fluid channel in which heat exchange is carried out between the hot water pipe 2 and the room-heating water circulating in the heat accumulation tank 1 is considerably increased, and the room-heating water introduced into the heat accumulation tank 1 is highly mixed to form a turbulent flow, so that the efficiency in heat exchange between the hot water pipe 2 and the room-heating water is further improved. Industrial Applicability

As can be seen from the foregoing, in the boiler according to the present invention, since the water supplied through the first discharge tube to the main heat exchanger is always the hot water stored in the heat accumulation tank, there happens neither a dewing phenomenon nor efflorescence phenomenon, which may happen when low-temperature water is directly introduced to the main heat exchanger. Further, the boiler according to the present invention does not employ a plate-type heat exchanger which is employed in the conventional boiler, so that there is less difficulty in manufacturing the boiler according to the present invention. Further, in the boiler according to the present invention, the three-way valve in the conventional boiler is replaced with a pump, so as to eliminate such problems as frequent troubles of the three-way valve or water-leakage.

Further, in the boiler according to the present invention, hot water for hot-bathing and room-heating water for heating a room, which are kept above a predetermined temperature, are always contained in the heat accumulation tank and the hot water pipe, and can be instantly supplied when a user wants. Therefore, the boiler according to the present invention requires nearly no delay or waiting time in either hot bath mode or room heating mode, thereby having a superior capability in instantly supplying hot water.

In general, predetermined pressure is formed at a source of water-supply to home. Therefore, in order to increase the dimension of a container to which such a pressure is applied, the thickness of the container must be correspondingly increase, so that there is difficulty in manufacturing containers of various sizes. However, in the boiler according to the present invention, the heat accumulation tank containing the room-heating water is so designed as that the pressure from the source of water-supply is not directly applied to the heat accumulation tank, which makes it easier to manufacture the boiler.

Moreover, the heat accumulation tank employed in the boiler according to the present invention can efficiently store and supply the room-heating water, and has a construction which can be modified in various ways, thereby having an excellent effect in heat exchange for generating hot water.

While this invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims .

Claims

1. A boiler comprising^': a heat accumulation tank containing room-heating water; a first means for heating the room-heating water discharged from the accumulation tank before returning the room-heating water to the accumulation tank; a second means for circulating the room-heating water from the accumulation tank through a heating- requiring space back to the accumulation tank; a third means for supplying hot water, the third means including a water-introduction port connected with a source of water-supply, a water-discharge port through which the hot water is discharged, and a heat transmission section disposed in the heat accumulation tank and having a tubular member connecting the water- introduction port and the water-discharge port with each other; and a control means for controlling operation of the first means according to temperature of the room-heating water in the heat accumulation tank and for controlling operation of the second means according to whether the boiler is in a room heating mode or not.

2. A boiler as claimed in claim 1, wherein the first means comprises: a main heat exchanger having an entrance port and an exit port, the entrance port being connected with a first discharge tube formed at the accumulation tank, the exit port being connected with a first introduction tube formed at the accumulation tank; a burner for supplying heat to the main heat exchanger; and a first circulation pump for circulating the room- heating water from the first discharge tube toward the first introduction tube.

3. A boiler as claimed in claim 1, wherein the second means comprises: a heating pipe disposed in the heating-requiring space, the heating pipe having an entrance port and an exit port, the entrance port of the heating pipe being connected with a second discharge tube formed at the heat accumulation tank, the exit port of the heating pipe being connected with a second introduction tube formed at the heat accumulation tank; and a second circulation pump for circulating the room-heating water from the second discharge tube toward the second introduction tube .

4. A boiler as claimed in claim 1, wherein the control means comprises: a temperature sensor provided at the heat accumulation tank; and a control panel operating the first means when temperature detected by the temperature sensor is lower than a predetermined value, the control panel generating a signal for operating the second means when the boiler is in the room heating mode.

5. A boiler as claimed in claim 1, further comprising an expansion tank communicating with the first means.

6. A heat accumulation tank for containing room- heating water of a boiler, the heat accumulation tank comprising: a first discharge tube through which the room- heating water contained in the heat accumulation tank flows to a first means for heating the room-heating water; a first introduction tube, through which the room- heating water heated by the first means returns to the heat accumulation tank; a second discharge tube, through which the room- heating water contained in the heat accumulation tank flows to a second means for circulating the room-heating water; a second introduction tube, through which the room-heating water returns to the heat accumulation tank after being circulated through a heating-requiring space by the second means; and a third means for supplying hot water, the third means including a water-introduction port connected with a source of water-supply, a water-discharge port through which the hot water is discharged, and a heat transmission section disposed in the heat accumulation tank and having a tubular member connecting the water- introduction port and the water-discharge port with each other.

7. A heat accumulation tank as claimed in claim 6, wherein the room-heating water is discharged through the first discharge tube from a lower portion of the heat accumulation tank, the room-heating water is introduced through the first introduction tube into an upper portion of the heat accumulation tank, the room-heating water is discharged through the second discharge tube from an upper portion of the heat accumulation tank, the room-heating water is introduced through the second introduction tube into a lower portion of the heat accumulation tank, and the heat transmission section is arranged in a spiral shape.

8. A heat accumulation tank as claimed in claim 6, wherein the first discharge tube is disposed above the heat accumulation tank, the heat transmission section is arranged in a spiral shape, and a suction tube extends downward from the first discharge tube and inside of the heat transmission section while a plurality of introduction holes are formed through a side of the suction tube.

9. A heat accumulation tank as claimed in claim 8, wherein each of the introduction holes has a flange protruding outward in a tubular shape .

10. A heat accumulation tank as claimed in claim 8 or 9, wherein the introduction holes have diameters which increase as locations of the introduction holes become lower.

11. A heat accumulation tank as claimed in claim 8 or 9, wherein the introduction holes are oriented in a direction opposite to a side to which the room-heating water heated in the main heat exchanger returns through the first introduction tube.

12. A heat accumulation tank as claimed in claim 8, wherein the introduction holes are formed through an upper portion of the suction tube; an outer suction tube is disposed surrounding the suction tube while a plurality of outer introduction holes are formed through a lower portion of the outer suction tube; and the heat transmission section is arranged in a double-spiral shape, which includes inner and outer spiral sections, the inner spiral section being disposed between the suction tube and the outer suction tube, the outer spiral section being disposed between the outer suction tube and a body of the tank.