Abstract:
In a heating medium utilizing apparatus utilizing heating medium heated by a heating device, it is aimed to provide a pipe which achieves both of the strength of a connection part to an external pipe and the ease of pipe layout without increasing a manufacturing time. On a tip portion of an internal pipe through which the heating medium or fluid to be heat-exchanged with the heating medium flows, a pipe expanding process to expand a pipe diameter and a pipe shrinking process to shrink the pipe diameter are carried out, thereby forming the connection part to be connected to the external pipe connected to external equipment by work hardening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims the benefit of priority from Japanese Patent Application No. 2013-014567, filed in Japan on Jan. 29, 2013, the content of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a heating medium utilizing apparatus utilizing heating medium, such as a water heater heating water in a tank using heating medium heated by a heating device, a heating apparatus delivering heating medium heated by a heating device to a floor heating panel, a radiator, and so on for heating. In particular, the present invention relates to, in the heating medium utilizing apparatus, connection technique of pipe to be connected with external equipments such as the heating device, the floor heating panel, the radiator, and so on. 
     BACKGROUND ART 
     In case of installing the heating medium utilizing apparatus at an installation site, a pipe connection part is often connected by a ring-type joint. As for the ring-type joint, a brass ring is compressed and deformed by nut and a copper pipe to be sealed, and thus the copper pipe needs to have a hardness being higher than the brass ring. 
     Patent Literature 1 describes that the copper pipe is processed, thereby producing a joint without using brass. Further, at the time of setting-up the ring-type joint, to avoid water leakage caused by deformation of the copper pipe, some products of copper pipe are made of H material to be used for a local pipe connection part. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP2007-85400A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When the copper pipe of H material is used, the hardness of the local connection part is sufficient; however, bending process cannot be done, or a bending radius has to be large, and thus the strength of the connection part and easy pipe layout within an apparatus cannot be achieved at the same time. Therefore, a soft copper pipe made of O material or OL material is used for a part which needs bending within the apparatus, the copper pipe of H material is used only for the connection part to an external equipment; the two types of copper pipes are connected by brazing. In this case, the connection needs two steps of bending and brazing by different manufacturing apparatuses, which causes a problem that the manufacturing time is long including a time for changing steps. 
     The present invention aims to achieve both of the strength of the connection part and the easy pipe layout within the apparatus, without increasing the manufacturing time. 
     Solution to Problem 
     According to the present invention, a heating medium utilizing apparatus utilizing heating medium heated by a heating device, the heating medium utilizing apparatus includes: 
     an internal pipe through which the heating medium or fluid that has been heat-exchanged with the heating medium flows; and 
     a connection part provided at a tip portion of the internal pipe to be connected to an external pipe connected to the heating device or another external equipment, the connection part formed by carrying out, on the tip portion, a pipe expanding process to expand a pipe diameter and a pipe shrinking process to shrink the pipe diameter. 
     Advantageous Effects of Invention 
     In a heating medium utilizing apparatus according to the present invention, a pipe expanding process and a pipe shrinking process are carried out to harden a tip portion of an internal pipe, thereby forming a connection part. Accordingly, there is no need to use the copper pipe made of H material having the high hardness for the connection part, but the internal pipe can be formed only by the copper pipe made of such as O material or OL material. Therefore, the two steps by different manufacturing apparatuses are unnecessary, which does not increase the manufacturing time, and thus the strength of the connection part and the easy pipe layout within the apparatus can be both achieved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention will become fully understood from the detailed description given hereinafter in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a configuration diagram showing a hot water supply heating system  100  according to a first embodiment. 
         FIG. 2  is an explanatory diagram of an operation of the hot water supply heating system  100  shown in  FIG. 1 . 
         FIG. 3  is an explanatory diagram of a connection part  33  ( 33   a  to  33   f  of  FIG. 1 ). 
         FIG. 4  is an explanatory diagram of a ring-type joint  60  which connects the connection part  33  and an external pipe  64 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In describing a preferred embodiment illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of the present invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve a similar result. 
     Embodiment 1 
       FIG. 1  is a configuration diagram showing a hot water supply heating system  100  according to the first embodiment. 
     The hot water supply heating system  100  includes a heat pump apparatus  10 , a heating medium utilizing apparatus  20 , a radiator  40 , and a shower  50 . 
     The heat pump apparatus  10  includes a compressor  11 , a heat exchanger  12 , an expansion valve  13 , and a heat exchanger  14 . The heating medium utilizing apparatus  20  includes an auxiliary heater  21 , a pump  22 , a three-way valve  23 , a coil  24 , a tank  25 , a strainer  26 , a pressure relief valve  27 , an air relief valve  28 , and an expansion tank  29 . 
     The compressor  11 , the heat exchanger  12 , the expansion valve  13 , and the heat exchanger  14  are connected in series by pipe, thereby forming a refrigerant circuit in which refrigerant circulates. The heat exchanger  12 , the auxiliary heater  21 , the pump  22 , the three-way valve  23 , the coil  24  in the tank  25 , and the strainer  26  are connected in series by pipe, thereby forming a water circuit in which water (an example of the heating medium) circulates. Further, branched at the three-way valve  23 , a heating circuit is provided, which connects the radiator  40  in the middle of the path and which merges onto a merging point  30  located between the coil  24  and the strainer  26 . To a lower part of the tank  25 , a cold water inlet pipe  31  to which cold water is supplied is connected, and to an upper part of the tank  25 , a hot water outlet pipe  32  delivering hot water to the shower  50  is connected. 
     When the hot water supply heating system  100  is installed at the installation site, the pipes  15  and  16  (an example of the external pipe  64  of  FIG. 4 ) connected to the heat exchanger  12  of the heat pump apparatus  10  are connected respectively to the connection parts  33   a  and  33   b  of the heating medium utilizing apparatus  20 . Further, the pipes  41  and  42  (an example of the external pipe  64  of  FIG. 4 ) connected to the radiator  40  are connected respectively to the connection parts  33   c  and  33   d  of the heating medium utilizing apparatus  20 . Further, the pipe  51  (an example of the external pipe  64  of  FIG. 4 ) connected to the water source is connected to the connection part  33   e  of the heating medium utilizing apparatus  20 , and the pipe  52  (an example of the external pipe  64  of  FIG. 4 ) connected to the shower  50  is connected to the connection part  33   f  of the heating medium utilizing apparatus  20 . 
       FIG. 2  is an explanatory diagram of the operation of the hot water supply heating system  100  shown in  FIG. 1 . 
     In  FIG. 2 , a solid-line arrow shows a flow of the refrigerant, and a broken-line arrow shows a flow of water. 
     In the refrigerant circuit, the refrigerant with high temperature and high pressure discharged from the compressor  11  is flown into the heat exchanger  12 . Then, in the heat exchanger  12 , the water circulating in the water circuit is heated and the refrigerant is cooled. The cooled refrigerant passes through the expansion valve  13 , is expanded into gas-liquid two-phase, and flown into the heat exchanger  14 . In the heat exchanger  14 , the refrigerant is heated by the outdoor air. The heated refrigerant is sucked by the compressor  11 , and the refrigerant has become high temperature and high pressure again. 
     In the water circuit, the water (hot water) heated by the heat exchanger  12  passes through the auxiliary heater  21 , and is further heated. The heated water passes through the pump  22  and the three-way valve  23 , and is flown into the coil  24 . In the coil  24 , the water in the tank is heated, and the water circulating in the water circuit is cooled. The cooled water passes through the strainer  26 , and is flown into the heat exchanger  12  again. 
     Further, a part of the water passing through the three-way valve  23  is flown into the radiator  40 . In the radiator  40 , the air of the room where the radiator  40  is installed is heated, and the water circulating in the water circuit is cooled. The cooled water merges to the water passing through the coil  24  at the merging point  30 .  FIG. 3  is an explanatory diagram of the connection part  33  (the connection parts  33   a  to  33   f ). 
     (a) of  FIG. 3  shows status before a processing (the original status), (b) of  FIG. 3  shows status after a pipe expanding process, and (c) of  FIG. 3  shows status after a pipe shrinking process. 
     The connection part  33  is formed at a tip portion of the pipe that forms the water circuit, the cold water inlet pipe  31 , and the hot water outlet pipe  32 . The tip portion is a part of the pipe within a range of, for instance, 100 mm from the tip. 
     First, on the pipe within the range of 100 mm from the tip, the pipe expanding process is carried out to expand a pipe diameter by 13 to 17%, and thus the status is changed from (a) of  FIG. 3  to (b) of  FIG. 3 . Next, on the pipe within the range of 80 mm from the tip, the pipe shrinking process is carried out to shrink the pipe diameter by 13 to 17%, and thus the status is changed from (b) of  FIG. 3  to (c) of  FIG. 3 . 
     By the above operation, the pipe within the range of 80 mm from the tip comes to have approximately the same pipe diameter as the pipe of the original status; the pipe within the range of 20 mm on which the pipe expanding process is carried out but the pipe shrinking process is not carried out becomes a swelling  34  which has a pipe diameter larger than the pipe of the original status. 
     The connection part  33  is formed by carrying out the pipe expanding process and the pipe shrinking process, and thus the hardness is increased compared with the original status because of the work hardening. 
     For instance, if a copper pipe of OL material having an external diameter of 22 mm is expanded to the external diameter of around 25 mm, and then shrunk to the external diameter of around 22 mm; when measured by the Vickers hardness, the hardness of the original status is around 60, the hardness after the expanding process is around 90, and the hardness after shrinking process (the shrunk portion) is around 110. 
     The hardness like H material is sufficient to withstand fastening by the ring-type joint. Since the hardness of the H material is around 104, the hardness 110 of the shrunk portion is higher than the hardness of the H material. Therefore, the shrunk portion withstands fastening by the ring-type joint. 
       FIG. 4  is an explanatory diagram of the ring-type joint  60  that connects the connection part  33  and the external pipe  64 . 
     In  FIG. 4 , a left half shows a frontal view of the ring-type joint  60 , and a right half shows an inside of the ring-type joint  60 . 
     The ring-type joint  60  includes nuts  61   a  and  61   b , rings  62   a  and  62   b , and a joint main body  63 . 
     When the connection part  33  and the external pipe  64  are connected, the connection part  33  is inserted to the ring  62   a , the external pipe  64  is inserted to the other ring  62   b , and the nuts  61   a  and  61   b  are fastened. Then, by fastening the nuts  61   a  and  61   b , the rings  62   a  and  62   b  are deformed and adhered to the connection part  33  and the external pipe  64 . Accordingly, the connection part  33  and the external pipe  64  are connected. 
     Here, the tip portion of the connection part  33  is provided with an opening so that the opening directs vertically upwardly. Therefore, the swelling  34  is located beneath the connection part  33 . 
     When the connection part  33  and the external pipe  64  are connected, while the connection part  33  is inserted to the ring  62   a  of the ring-type joint  60 , the connection part  33  does not fall down even if the connection part  33  is not supported by hand, since the nut  61   a  is caught by the swelling  34 . That is, the swelling  34  works as a stopper for the nut  61 . Therefore, the connection work becomes easier. 
     As discussed above, in the hot water supply heating system  100  according to the first embodiment, the heating medium utilizing apparatus  20  is configured to have the connection part  33  hardened by the processing. Therefore, the connection part  33  having the high hardness and a part which is bendable can be formed by one pipe. 
     Here, in the foregoing explanation, the heating medium utilizing apparatus  20  of the hot water supply heating system  100  has been explained. However, the above technique can be applied to the heating medium utilizing apparatus  20  of a hot water supply system to which the radiator  40  is not connected or a heating system without having the tank  25  and the like. 
     Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the disclosure of this patent specification may be practiced otherwise than as specifically described herein. 
     REFERENCE SIGNS LIST 
       100 : hot water supply heating system;  10 : heat pump apparatus;  11 : compressor;  12 : heat exchanger;  13 : expansion valve;  14 : heat exchanger;  15 ,  16 : pipes;  20 : heating medium utilizing apparatus;  21 : auxiliary heater;  22 : pump;  23 : three-way valve;  24 : coil;  25 : tank;  26 : strainer;  27 : pressure relief valve;  28 : air relief valve;  29 : expansion tank;  30 : merging point;  31 : cold water inlet pipe;  32 : hot water outlet pipe;  33 : connection part;  34 : swelling;  40 : radiator;  41 ,  42 : pipes;  50 : shower;  51 ,  52 : pipes;  60 : ring-type joint;  61 : nut;  62 : ring;  63 : joint main body, and  64 : external pipe.