Description of the Prior Art: Fig. 1 shows the format of the got water generator by heat pump which is made by the conventional technique. This hot water generator can be found easily at public bath, motel and industrial facilities that use much hot water.

In the above conventional device, the several parts (the compressor (l), the first heat exchanger (3), the expanding valve (5), the second heat exchanger (6) ) are connected by the linking pipe (7). The operating fluid fluctuating in those parts, heat is exchange.

The above mentioned first heat exchanger (3) is connected with the hot water tank.

The water keeping relatively low level of temperature is supplied from the hot water tank (8) to the first heat exchanger (3). And then, heat is exchanged between the water and the operating fluid. So, the warmed water is again supplied to the hot water tank (8). The conduit (10) is linked with the second heat exchanger (6). This linkage is to transfer the

heat generated from the disused hot water to the second heat generator (7). The transferred heat is used to vaporize the operating fluid. Usually, the cell and tube method is used in the above mentioned second heat exchanger.

The mark"2"means the oil separator, which is made to separate oils from the operating fluid. The mark"4"means the fluid accepting device, which makes only the operating fluid to be transferred to the expanding valve (5).

In this conventional device, the gaseous operating fluid of high temperature and high pressure, which was compressed by the compressor (1), is supplied to the first heat exchanger (3). And then, it transmits heat to the cold water which is from the hot water tank (8) so that the hot water is generated. In this heat exchanging process, the above mentioned operating fluid is condensed and becomes the liquid of low temperature and low pressure.

This condensed operating fluid is supplied to the fluid accepting device (4). From the fluid accepting device (4), only the operating fluid in the state of liquid are transmitted to the expanding valve. And then, it is expanded to be vaporized easily and becomes liquid state of relatively low temperature and low pressure. This expanded operating fluid are provided with heat of disused hot water from the second heat exchanger (6) and changed its state into the gas of relatively high temperature and high pressure.

However, in the above mentioned conventional technique, there are some problems as following.

Primarily, the disused hot water of low grade is supplied to the inside of the second heat exchanger (6) which adopts the cell and tube method, and provide heat to

vaporize the operating fluid. Therefore the foreign body in the disused hot water contaminates the above second heat exchanger (6) easily. There is a problem that the device should be cleaned frequently.

Particularly, it is difficult to start the cycle itself, because at the time of first starting the cycle there is no disused hot water and heat exchange is not happened in the second heat exchanger. To solve this problem, in the conventional device, a separated boiler is used. It heats the cold water in the above mentioned hot water tank (8) and provides the hot water. And then, after the above mentioned hot water is used and the disused hot water is generated, the system is operated normally. So, there is the problem that a separated boiler is necessary to start the cycle.

And in the conventional technique, there is the problem that, if the temperature of the cold water that is transmitted to the first heat exchanger (3) is relatively low, the temperature of the transpired hot water which is transmitted to the hot water tank (8) becomes relatively low, because the cycle is operated without keeping the pressure of the operating fluid, which passes the above mentioned first heat exchanger (8), at the defined level constantly.

SUMMARY OF THE INVENTION The present invention is a hot water generator by heat pump. It consists of the following parts: the heat exchanging cycle which includes the compressor (in), the first heat exchanger (20), the expanding side (30) and the second heat exchanger (40); the hot water tank (50) in which hot water that is generated by heat exchange between the

operating fluid and the cold water supplied to the above the first heat exchanger (20); the subsidiary heat exchanger (25) to which the operating fluid is transferred from the compressor (in), that is devised between the above compressor (l0) and the expanding side (30); the external water tank (60) in which the heat of the operating fluid is transferred from the above subsidiary heat exchanger, and which supplies hot water to vaporize the operating fluid in the above mentioned the second heat exchanger (40); the pressure controlling valve (70,70') which is devised on the conduit (80) connected with the above compressor (10), the first heat exchanger (20), the expanding side (30) and the second heat exchanger (40), and makes the operating fluid to fluctuate in the conduit (80) only when the pressure of fluid becomes the defined level. The present invention makes the hot water generator to work more stably, improves its durability and makes it possible to be provided with the hot water of the constant temperature always.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned aspects and other features of the present invention will be explained in the following description, taken in conjunction with the accompanying drawings, wherein: Fig. 1 is a format diagram of the conventional hot water generator by heat pump.

Fig. 2 is a format diagram of the desirable hot water generator by heat pump, made by the present invention

10 : compressor 12: oil separator 20 : the first heat exchanger 22: controlling valve 25 : subsidiary heat exchanger 28: fluid heating device 29 : fluid accepting device 30: expanding side 40 : the second heat exchanger 50: hot water tank 52: water supplier 54: pump 55: valve 56: check valve 60: external water tank 70, 70' : pressure controlling valve 80: conduit DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is a hot water generator, in detail, which generates hot water using heat pump.

The technical tasks that the present invention; The purpose of this invention is to solve the above mentioned problems and to improve the reliance of the operation of hot water generator.

Another purpose of this invention is to provide the hot water generator that is not influenced by the volume of supplied disused hot water.

And the additional purpose of this invention is to provided the hot water generator that can provide the hot water of constant temperature always.

The structure and function of the present invention;

To achieve the above mentioned purpose, the present invention consists of the following parts: the heat exchanging cycle which includes the compressor, the first heat exchanger, the expanding side and the second heat exchanger; the hot water tank in which hot water that is generated by heat exchange between the operating fluid and the cold water supplied to the above the first heat exchanger; the subsidiary heat exchanger to which the operating fluid is transferred from the compressor, that is devised between the above compressor and the expanding side; the external water tank in which the heat of the operating fluid is transferred from the above subsidiary heat exchanger, and which supplies hot water to vaporize the operating fluid in the above mentioned the second heat exchanger; the pressure controlling valve which is devised on the conduit connected with the above compressor, the first heat exchanger, the expanding side and the second heat exchanger, and makes the operating fluid to fluctuate in the conduit only when the pressure of fluid becomes the defined level.

The above mentioned subsidiary heat exchanger is parallel connected with the first heat exchanger. And, at the entrance of the above subsidiary heat exchanger, the more controlling valves are devised to control the volume of the operating fluid which is transmitted from the compressor.

The above mentioned pressure controlling valves include the pressure controlling valve at the high pressure side which is devised between the first heat exchanger and the expanding side, and the pressure controlling valve at the low pressure side which is devised between the compressor and the second heat exchanger.

The more fluid heating devices are devised to facilitate the heat exchange between

the operating fluids which respectively passed the above mentioned pressure controlling valves at both sides of high pressure and low pressure.

With this structure, the present invention has the advantage that the hot water generator can be operated more smoothly, that its durability can be improved, and that it can provide hot water more stably.

The desirable executing example is described as follows.

As shown in the Fig. 2, the present example include the following heat pump cycle to generate hot water: the compressor (in), the first heat exchanger (20), the expanding side (30) and the second heat exchanger (40).

The above compressor 10) compresses the operating fluid into the gaseous state of high temperature and high pressure. The oil separator (12) is devised at the gateway of the compressor (10). This oil separator (l2) separates the mixed oils, which comes from the compressor (10), from the operating fluid.

The first heat exchanger (20) is devised, connected with the gateway of the compressor (in). In this first heat exchanger (20), heats are exchanged between the operating fluid and the water. The heat are transferred from the operating fluid to the water. Thus, the hot water is generated. In this process, the above operating fluid are condensed into the liquid state of high temperature and high pressure. It is desirable to use the plate-type heat exchanger as the first heat exchanger.

To be provided with the operating fluids from the compressor, the subsidiary heat exchanger (25) is devised connected parallel with the first heat exchanger (20). To control

the supply of the operating fluids to the subsidiary heat exchanger (25), the controlling valve (22) is devised at the entrance of the subsidiary heat exchanger (25). The controlling valve (22) provides selectively the operating fluids from the compressor 10) to the subsidiary heat exchanger (25). The subsidiary heat exchanger (25) transfers heat to the water which are supplied from the separated external water tank (60). Thus, the heat is transferred to vaporize the operating fluids at the second heat exchanger (40).

The fluid heating device (28) exchanges heat between the operating fluids from both the first heat exchanger (20) and the subsidiary heat exchanger (25) and the operating fluids transferred to the compressor (in). At this time, the heat is transferred from the liquid operating fluids of relatively high temperature that came from the heat exchangers (20,25), to the operating fluids to be transferred to the compressor (l 0). And it changes the state of the operating fluids to be transferred to the compressor (10) into easily vaporizable state.

The fluid accepting device (29) collects only the liquid operating fluids from the operating fluids which came from the fluid heating device (28) and transmits them to the expanding side (30). The expanding side (30) expands the operating fluids into the state of relatively low temperature and low pressure so that they can be vaporized easily in the second heat exchanger (40).

In the second heat exchanger (40), heat are transferred from the waters that passed the subsidiary heat exchanger (25) to the operating fluids, and the operating fluids are vaporized. Therefore, the heat to vaporize the operating fluids are supplied from the subsidiary heat exchanger (25). Through this process, the operating fluids in the second

heat exchanger (40) changes its own state into the gaseous state of relatively low temperature and low pressure. The entrance of second heat exchanger (40) is connected with the expanding side (30). And, its gateway is connected with the fluid heating device (28).

In this invention, to provide heat that can vaporize the operating fluids in the second heat exchanger (40), the subsidiary heat exchanger (25) is used. That is, connecting the external water tank (60) and the subsidiary heat exchanger (25), the waters which are supplied from the external water tank (60) are provided with heat from the operating fluids in the subsidiary heat exchanger (25) and their temperature is moved up. The water of relatively high temperature are supplied to the second heat exchanger (40) and provides the heat to vaporize the operating fluids. And then, they are changed into the state of relatively low temperature and transmitted to the external water tank (60).

On the other hand, in the first heat exchanger, the hot waters are generated. The cold waters are provided from the source of water (52) to the first heat exchanger (20). At this time, to control the volume of cold waters which are provided from the source of water (52) to the first heat exchanger (20), the following devices are devised: pumps (54, 54'), valves (55,55'), and check valves (56,56'). And those devices are connected parallel.

In normal times, one pump, one valve and one check valve are used. If the first heat exchanger (20) is overheated, the all pumps (54,54'), valves (55,55') and check valves (56,56') should be operated so that the relatively much volume of cold waters can be provided into the first heat exchanger (20).

Here, the pumps (54, 54') provide the power to move waters. The valves (55,55') control the volume of supplied waters. The check valves (56,56') prevent the backward flow of waters. Of course, according to the condition of design, the number of pumps (54, 54'), valves (55, 55') and check valves (56,56') can be changed. And, it is possible to control the volume of the cold waters, using only pump (54), valve (55) and check valve (56) which have relatively large capacity.

Additionally, the following structure can be made : the entrance of the source of waters (52) is directly connected with the hot water tank (50); the assemblies such as pumps (54,54') are devised at the gateway of the hot water tank (50) so that the waters in the hot water tank (50) can be provided to the first heat exchanger (20) and then warmed and transmitted again into the hot water tank (50).

On the other hand, the waters which are provided with heat from the subsidiary heat exchanger (25) and provide the heat to vaporize the operating fluids in the second heat exchanger (40) are provided from the external water tank (60). The external water tank (60) is devised out of the room. Therefore, according to the environment of the device, the amount of heat that is transferred from the subsidiary heat exchanger (25) to the external water tank (60) can be changed. For instance, when the external water tank (60) is devised in the environment of high temperature, it is sufficient to provide the relatively small volume of operating fluids to the subsidiary heat exchanger (25), operating the controlling valve (22). Because the temperature of the external water tank (60) is relatively high in the summer in Korea, it is possible to operate the controlling valve (22) and to reduce the

operating fluids which are transmitted to the subsidiary heat exchanger (25).

The pressure controlling valve (70,70') is devised at one side of the conduit (80) which links the compressor (10), the first heat exchanger (20), the expanding side (30) and the second heat exchanger (40). The pressure controlling valve (70, 70') is to allow the flow of the operating fluids only when its pressure is more than a certain value. If the pressure is not the same of the defined value, the operating fluids can not flow into the conduit (80) by the pressure controlling valve (70,70'). And as the compressor 10) works continuously and the pressure of the operating fluids becomes the defined level, the operating fluids can be flow into the conduits (80).

Devising the pressure controlling valves (70,70'), the operating fluids with constant defined pressure can be provided to the first heat exchanger (20). Thus, the hot waters transpired from the first heat exchanger (20) can keep always the constant temperature.

The functions of the heat-pump type hot water generator by the present invention are described as follows.

The hot water generator by the present invention starts to move when the operating fluids change into the gaseous state of high temperature and high pressure by the compression in the compressor (l0) and the cycle starts to move. At this time, the operating fluids do not flow into the conduit (80) until they have the defined pressure by the pressure controlling valve (70,70'). Under the defined pressure, the operating fluids start to move through the conduit (80). Here, the pressure controlling valve (70) at the side of high pressure is set up to be opened only at the relatively high pressure and the pressure

controlling valve (70') is set up at the relatively low pressure.

When the operating fluids came from the compressor (10) pass the oil separator (12), oils are separated and only operating fluids flows. And then, the above operating fluids of high temperature and high pressure are transmitted to the first heat exchanger (20) and the subsidiary heat exchanger (25), and then their heats are exchanged with waters so that the hot waters are generated in the first heat exchanger (20). And the heat required to vaporize the operating fluids are provided from the subsidiary heat exchanger (25) to the second heat exchanger (40).

The volume of the operating fluids provided to the subsidiary heat exchanger (25) is controlled by the controlling valve (22). Particularly, according to the devising environment of the external water tank (60), the volume of the operating fluids provided to the subsidiary heat exchanger (25) is controlled. In Korea's summer, because the temperature of the external water tank (60) is relatively high, the amount of heat to be transferred becomes relatively less. In winter, because the amount of heats to be transferred is relatively much, it is necessary to provide the relatively much operating fluids to the subsidiary heat exchanger (25) operating the controlling valve (22).

The operating fluids which exchanged its heat in the first heat exchanger (20) become the state of relatively low temperature and high pressure. The above operating fluids are transpired from the first heat exchanger (20) and transmitted to the fluid heating device (28). In the fluid heating device (28), the operating fluids which are to enter the compressor 10) exchanges their heat with the operating fluids which came from the first heat exchanger (20). In this way, heats are transferred to the operating fluids which is

entering the compressor so that they can be changed into the gaseous state.

The operating fluids which came from the fluid heating device (28) are transmitted to the fluid accepting device (29). From the fluid accepting device (29), only the liquid operating fluids are transmitted to the expanding side (30). The expanding side (30) expands the operating fluids and changes their state into that of easily vaporizable in the second heat exchanger (40).

The expanded operating fluids from the expanding side enters the second heat exchanger (40). They are provided with heats from the subsidiary heat exchanger (25), and then they are vaporized by heats provided from the water of a certain temperature and changed into the state of gas. The warmed waters in the subsidiary heat exchanger (25) exchanges their heats in the second heat exchanger (40), and their temperature moved down, and the waters are transmitted to the external water tank (60). The operating fluids which were transpired from the second heat exchanger (40) are provided with heat in the fluid heating device (28) from the operating fluids, which were transpired from the first heat exchanger (20). They become gases and are transmitted to the compressor (10).

As described in the above, in this invention, heats are exchanged between the different operating fluids in the fluid heating device. And then the gaseous operating fluids enter the compressor (I O) so that the efficiency of the compressor (l0) can be improved.

On the other hand, the present invention makes the waters in the external water tank (60) into the state of relatively high temperature by exchanging their heats with the operating fluids in the subsidiary heat exchanger (25), and uses the heat of the above

waters to vaporize the operating fluids in the second heat exchanger (40). At this time, it is possible to use both types of heat exchanger, the cell-and-tube type or the plate type.

Because the relatively pure waters are used, it is unnecessary to clean out the second heat exchanger (40) frequently.

And, the waters to provide heats for the vaporization of the operating fluids in the second heat exchanger (40) can be provided always at a constant state, because a constant volume of waters are secured always in the external water tank (60) and the subsidiary heat exchanger (25) can be provided with the required amount of heats always.

In this way, if a constant heats always can be provided to the second heat exchanger (40), the vaporization of operating fluids in the second heat exchanger can be kept constantly so that the whole hot water generator can work smoothly. And, because the gaseous operating fluids of high temperature and high pressure which were compressed in the compressor (10) are provided to the subsidiary heat exchanger (25), it is not necessary to warm water by the separated source of heat at the starting time of this device.

Because of the pressure controlling valve (70,70'), the temperature of hot waters which are generated in the first heat exchanger (20) are always kept constantly, no matter how much high be the temperature of waters that were set up in the first heat exchanger (20) at firs. It is possible, because the pressure controlling valve (70) keeps the pressure of operating fluids at a certain level in the first heat exchanger (20). That is to say, because the pressure of operating fluids are always kept at the defined level in the first heat exchanger (20), the heat exchanges are achieved at the optimal condition. The

temperature of hot waters which are transpired from the first heat exchanger (20) are kept always at a constant level, except for the case that the waters of extremely cold inputted.

The present invention does not use the disused hot water. In stead of that, waters in the external water tank (60) are provided with heats from the subsidiary heat exchanger (25) and provide the required heats to vaporize the operating fluids in the second heat exchanger (40). Because this device does not use the disused hot water like as the conventional devices, it is easier to maintain and to preserve the second heat exchanger (40) than that of the conventional.

It is obvious that the rights of the present invention are not limited to the above described example of execution, that they are defined in accordance with the records of "What claimed is", and that one who has the knowledge of this area can try to transform this invention diversely and to remake.

For instance, one can use the hot waters from this invention for the purpose of heating the room and can use the cold water form the heat-exchanged water in the second heat exchanger for the purpose of cooling room.

The effect of the present invention; As mentioned above, the heat-pump type hot water generator by the present invention has the following effects.

Primarily, because the clean waters which are provided from the external water tank are used to make heat for the vaporization of the operating fluids in the second heat exchanger, it can save the costs to preserve and to maintain the hot water generator.

Particularly, because it do not use the disused hot waters but the clear waters from the

external water tank, it can improve the durability of the second heat exchanger.

And, because the required heats in the second heat exchanger are provided by the waters from the external water tank, the operating fluids. are vaporized smoothly in the second heat exchanger so that the whole hot water generator can work smoothly.

Devising the pressure controlling valves at the conduit, the operating fluids can flow and the hot water generator can start to work, only when their pressure are over the defined value. Therefore, the temperature of hot waters which are generated in the first heat exchanger can be kept at the constant level so that the hot waters can be provided stably.