Patent Publication Number: US-2017363301-A1

Title: Hot water supply apparatus provided with pressure reducing valve

Description:
TECHNICAL FIELD 
     The present invention relates to a hot water supply apparatus provided with a pressure reducing valve, and more particular, to a hot water supply apparatus provided with a pressure reducing valve capable of minimizing a temperature deviation of hot water while using hot water. 
     BACKGROUND ART 
     In general, a hot water supply apparatus is an apparatus for heating direct water to a predetermined temperature within a short time of period so that a user can conveniently use hot water. 
       FIG. 1  is a schematic view illustrating a configuration of a conventional hot water supply apparatus. 
     Upon review of the conventional hot water supply apparatus, a flow rate sensor  1  is provided for measuring a flow rate of direct water introduced through a direct water inlet pipe  5 , the direct water introduced to a heat exchanger  8  is heated by heat exchanging with combustion heat generated by a burner  7  from combustion of air provided from a blower  6  and gas, and is discharged through a hot water supply pipe  9 , and a flow adjustment valve  4  is provided on the hot water supply pipe  9  for adjusting a flow rate of hot water. 
     Further, a bypass pipe  2  is connected between the direct water inlet pipe  5  and the hot water supply pipe  9  such that the introduced direct water is directly transferred to the hot water supply pipe  9  side without passing through the heat exchanger  8 , and therefore a temperature of hot water may be adjusted by mixing hot water heated by passing through the heat exchanger  8  with the direct water. 
     Further, a mixing valve  3  is provided on the bypass pipe  2  so that a flow rate of direct water transferred through the bypass pipe  2  is adjusted. 
     When a user increases hot water usage flow rate while using hot water utilizing a hot water supply apparatus  10  with such constitutions, the flow rate of direct water introduced through the direct water inlet pipe  5  immediately increases, however, a temperature increase of the hot water provided to the hot water supply pipe  9  after passing through the heat exchanger  8  occurs relatively late, and thus there is a problem in that time is consumed until hot water having a temperature set by the user is provided. 
     On the contrary, when the user decreases the hot water usage flow rate while using hot water, the flow rate of direct water introduced through the direct water inlet pipe  5  immediately decreases, however, a temperature decrease of the hot water provided to the hot water supply pipe  9  after passing through the heat exchanger  8  occurs relatively late, and thus there is a problem in that time is consumed until hot water having a temperature set by the user is provided. 
     To address such problems, the mixing valve  3  is provided on the bypass pipe  2 . When the flow rate sensor  1  detects that a flow rate of the direct water introduced through the direct water inlet pipe  5  is changed, a controller (not shown) controls the degree of opening of the mixing valve  3  to adjust the flow rate of the direct water which is mixed in the hot water supply pipe  9  through the bypass pipe  2 , thereby hot water having a temperature set by the user is provided. 
     However, because the mixing valve  3  needs a constitution for adjusting the degree of opening, there are problems in that a structure of the valve is complex and the cost of the valve is high, costs of a system configuration for controlling the mixing valve  3  increase, and time is consumed until the degree of opening of the mixing valve  3  is adjusted after the flow rate sensor  1  detects the flow rate. 
     As an example of such prior art, ‘PIPE CONNECTING STRUCTURE OF WATER HEATER’ is disclosed in Korean Patent Registration No. 10-1179812. 
     DISCLOSURE 
     Technical Problem 
     Therefore, the present invention is directed to providing a hot water supply apparatus provided with a pressure reducing valve capable of minimizing temperature deviations of hot water provided to a user even when a hot water usage flow rate is changed. 
     Technical Solution 
     One aspect of the present invention provides a hot water supply apparatus which includes a direct water inlet pipe into which direct water is introduced; a heat exchanger for heating the direct water introduced through the direct water inlet pipe with combustion heat of a burner; a hot water supply pipe for discharging the hot water heated in the heat exchanger; a bypass pipe connected between the direct water inlet pipe and the hot water supply pipe so as to mix a part of the direct water introduced through the direct water inlet pipe with the hot water discharged through the hot water supply pipe; and a pressure reducing valve provided on the bypass pipe and configured to reduce a pressure of water passing through the inside of the bypass pipe to supply the water to the hot water supply pipe when hot water is supplied. 
     As the flow rate of the direct water introduced into the direct water inlet pipe increases, the pressure reducing valve may increase a flow rate of the water passing through the inside of the direct water inlet pipe up to a set flow rate, and then maintains at a constant flow rate. 
     The pressure reducing valve may include a direct water flow path, through which the water passes, formed therein and an elastic member which is deformed into a predetermined shape by supply pressure of the direct water provided to the direct water flow path so that the elastic member restricts a flow rate of the water passing through the direct water flow path and also maintains at a constant flow rate. 
     Advantageous Effects 
     A hot water supply apparatus provided with a pressure reducing valve according to the present invention can respond to a change in a hot water usage flow rate of a user with a simple configuration of providing a pressure reducing valve on a bypass pipe without providing any separate controller, and minimize temperature deviations of hot water because a mixing rate is rapidly changed to accelerate responsibility to changes of the hot water usage flow rate. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view illustrating a configuration of a conventional hot water supply apparatus. 
         FIG. 2  is a schematic view illustrating a configuration of a hot water supply apparatus according to a first embodiment of the present invention. 
         FIG. 3  is a cross-sectional view illustrating an internal structure of a pressure reducing valve according to one embodiment of the present invention. 
         FIG. 4  is a cross-sectional view illustrating a state in which an elastic member is deformed according to a change in supply pressure of direct water at the pressure reducing valve of  FIG. 3 . 
         FIG. 5  is a graph illustrating a flow rate change according to supply pressure of direct water at the hot water supply apparatus of the present invention. 
         FIG. 6  is a graph illustrating a temperature change of hot water according to a flow rate change in the hot water supply apparatus of the present invention. 
         FIG. 7  is a schematic view illustrating a configuration of a hot water supply apparatus according to a second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 100, 200: Hot water supply apparatus 
                 111, 211: Direct water inlet pipe 
               
               
                 112, 212: Hot water supply pipe 
                 113, 213: Bypass pipe 
               
               
                 121, 221: Direct water temperature 
                 122, 222: Flow rate sensor 
               
               
                 sensor 
               
               
                 123, 223: Heat exchanger temperature 
               
               
                 sensor 
               
               
                 124, 224: Hot water temperature sensor 
               
               
                 130, 230: Pressure reducing valve 
                 131: Valve body 
               
               
                 132 : Cylindrical member 
                 132a: Guide rib 
               
               
                 132b: Guide groove 
                 132c, 132d: Protrusion piece 
               
               
                 133: Center column member 
                 134: Elastic member 
               
               
                 135: Direct water passing hole 
                 140, 240, 241: Heat exchanger 
               
               
                 150, 250: Burner 
                 160, 260: Blower 
               
               
                 214: Heating supply pipe 
                 215: Heating recycle water pipe 
               
               
                 216: Heating water supply pipe for 
                 270: Circulation pump 
               
               
                 supplying hot water 
               
               
                 271: Heating water supply 
                 272: Three-way valve 
               
               
                 temperature sensor 
               
               
                   
               
            
           
         
       
     
     Modes of the Invention 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     A First Embodiment 
       FIG. 2  is a schematic view illustrating a configuration of a hot water supply apparatus according to a first embodiment of the present invention. 
     The hot water supply apparatus  100  according to the first embodiment of the present invention is provided with a pressure reducing valve  130  in a water heater, and is configured to include direct water inlet pipes  111   a  and  111   b  into which direct water is introduced, a heat exchanger  140  for heating the direct water introduced through the direct water inlet pipes  111   a  and  111   b  with combustion heat of a burner  150 , hot water supply pipes  112   a  and  112   b  for discharging the hot water heated in the heat exchanger  140 , a bypass pipe  113  connected between the direct water inlet pipes  111   a  and  111   b  and the hot water supply pipes  112   a  and  112   b  so as to mix a part of the direct water introduced through the direct water inlet pipe  111   a  with the hot water discharged through the hot water supply pipe  112   b ; and a pressure reducing valve  130 , provided on the bypass pipe  113 , for reducing the pressure of water passing through the inside of the bypass pipe  113  to supply the water to the hot water supply pipe  112   b  when hot water is supplied. 
     A direct water temperature sensor  121  for measuring a temperature of direct water and a flow rate sensor  122  for measuring flow rate of direct water are provided on the direct water inlet pipe  111   a.    
     A heat exchanger temperature sensor  123  for measuring a temperature of hot water heated by heat-exchanging in the heat exchanger  140  and a hot water temperature sensor  124  for measuring a temperature of hot water in which direct water provided through the bypass pipe  113  and hot water are mixed and provided to a user are provided on the hot water supply pipes  112   a  and  112   b.    
     The bypass pipe  113  is connected to supply a part of the direct water introduced through the direct water inlet pipe  111   a  to the hot water supply pipe  112   b  in order to control a temperature of the hot water provided through the hot water supply pipe  112   b.    
     The pressure reducing valve  130  for controlling a flow rate of the direct water provided through the bypass pipe  113  is configured to reduce the pressure of the direct water provided from the direct water inlet pipe  111   a  so that a constant flow rate of the direct water is provided to the hot water supply pipe  112   b.    
     When the hot water usage flow rate of a user is changed, the flow rate of direct water which passes through the inside of the pressure reducing valve  130  increases up to a certain extent as the hot water usage flow rate increases. However, when the hot water usage flow rate exceeds the certain extent, the flow rate of direct water which passes through the inside of the pressure reducing valve  130  is maintained constantly even when the hot water usage flow rate increases. 
     While the flow rate of direct water which passes through the pressure reducing valve  130  is maintained at the constant flow rate after being increased by a predetermined flow rate, the remaining amount of the direct water except an amount of the direct water which passes through the pressure reducing valve  130  is provided to the heat exchanger  140 . Therefore, when the hot water usage flow rate is changed, the flow rate provided to the heat exchanger  140  is changed together with the change in the hot water usage flow rate accordingly, a mixing rate, which is a ratio of the hot water heated in the heat exchanger  140  and provided to the hot water supply pipe  112   a  and the flow rate of the direct water which passes through the pressure reducing valve  130 , is changed together with the change in the hot water usage flow rate, thereby temperature deviations of hot water are minimized. 
     The pressure reducing valve  130  has a very simple structure and automatically changes the mixing rate according to the supply pressure of the direct water, thereby an overall system configuration is very simply implemented. 
     Non-described reference numerals  150  and  160  indicate a burner and a blower, respectively. 
       FIG. 3  is a cross-sectional view illustrating an internal structure of a pressure reducing valve according to one embodiment of the present invention, and  FIG. 4  is a cross-sectional view illustrating a state in which an elastic member is deformed according to a change of supply pressure of direct water in the pressure reducing valve of  FIG. 3 . Hereinafter, referring to  FIGS. 3 and 4 , a configuration and an effect of the pressure reducing valve according to one embodiment of the present invention will be described. 
     The pressure reducing valve  130  is configured to include a valve body  131  formed as a whole by injection molding, and an elastic member  134  which is inserted into the inside of the valve body  131  and restricts a flow path of direct water by being deformed by the supply pressure of the direct water. 
     The valve body  131  is configured to include a cylindrical member  132  in which the flow path of direct water is formed therein, and a center column member  133  provided at a center portion of an inner side of the cylindrical member  132 . 
     The elastic member  134  is inserted between an inner surface of the cylindrical member  132  and an outer surface of the center column member  133 , and when the direct water is introduced, the elastic member  134  is compressed to expand in a lateral direction as in  FIG. 4 , thereby a cross-sectional area of the flow path through which the direct water passes is changed. 
     As a configuration for guiding a flow of the direct water, guide ribs  132   a  which protrude at regular intervals in a circumferential direction are formed on the inner surface of the cylindrical member  132 , and guide grooves  132   b  are formed between neighboring guide ribs  132   a.    
     A protrusion piece  132   c  protruding in a certain length toward the center axis of the center column member  133  is formed at an upper part of the guide rib  132   a , and a protrusion piece  132   d  protruding in a certain length toward the center column member  133  is also formed at an upper part of the guide groove  132   b . A direct water passing hole  135  which is a flow path through which the direct water passes is formed so that the protrusion piece  132   c  protruding from the guide rib  132   a  and the protrusion piece  132   d  protruding from the neighboring guide groove  132   b  have steps formed to cross therebetween in a vertical direction. 
     In a low pressure state in which the supply pressure of the direct water is equal to or less than a certain pressure, a cross section of the elastic member  134  maintains a nearly circular shape as shown in  FIG. 3 , and therefore the flow path in which the direct water flows is widely formed in a space between the elastic member  134  and the outer surface of the center column member  133  and a space between the elastic member  134  and the inner surface of the cylindrical member  132  so that the introduced direct water passes through the flow path intactly. 
     On the contrary, when the pressure of the direct water increases, the elastic member  134  is deformed to a flat elliptical shape by the supply pressure of the direct water as shown in  FIG. 4 . Because the flow path through which the direct water flows is restricted to the space between the elastic member  134  and the outer surface of the center column member  133  so that the flow path is narrowly formed, the passing flow rate of the introduced direct water is restricted to a certain amount or less. 
     In the case, the elastic member  134  is deformed only within a certain extent, and the shape of the cross section thereof is not changed even when the supply pressure of the direct water further increases. Therefore, the passing flow rate of the direct water is constantly maintained. 
       FIG. 5  is a graph illustrating a flow rate change according to the supply pressure of direct water in the hot water supply apparatus of the present invention,  FIG. 6  is a graph illustrating a temperature change of hot water according to a flow rate change in the hot water supply apparatus of the present invention, the following Table 1 is a table showing a flow rate which passes through each pipe and a mixing rate, and the following Table 2 is a table showing relations between a flow rate, temperature, and mixing rate. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Flow rate of heat 
                   
               
               
                 Overall flow rate 
                 Mixing flow rate 
                 exchanger 
                 Mixing rate 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 3 
                 1.2 
                 1.8 
                 0.40 
               
               
                 4 
                 1.5 
                 2.5 
                 0.38 
               
               
                 6 
                 1.5 
                 4.5 
                 0.25 
               
               
                 8 
                 1.5 
                 6.5 
                 0.19 
               
               
                 10 
                 1.5 
                 8.5 
                 0.15 
               
               
                 12 
                 1.5 
                 10.5 
                 0.13 
               
               
                 14 
                 1.5 
                 12.5 
                 0.11 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Overall 
                 Temperature of 
                 Temperature of 
                 Temperature of 
                 Mixing 
               
               
                 flow rate 
                 heat exchanger 
                 hot water 
                 direct water 
                 rate 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 3 
                 61.5 
                 45 
                 20 
                 0.40 
               
               
                 4 
                 60 
                 45 
                 20 
                 0.38 
               
               
                 6 
                 53.5 
                 45 
                 20 
                 0.25 
               
               
                 8 
                 51 
                 45 
                 20 
                 0.19 
               
               
                 10 
                 49.5 
                 45 
                 20 
                 0.15 
               
               
                 12 
                 48.6 
                 45 
                 20 
                 0.13 
               
               
                 14 
                 48 
                 45 
                 20 
                 0.11 
               
               
                   
               
            
           
         
       
     
     In  FIG. 5  and Table 1, the mixing flow rate refers to a flow rate of direct water which is provided to the hot water supply pipes  112   a  and  112   b  after passing through the bypass pipe  113 , of the direct water introduced through the direct water inlet pipe  111   a , and mixes with hot water flowing in the hot water supply pipe  112   a , the flow rate of heat exchanger refers to a flow rate of hot water heated in the heat exchanger  140  and then provided to the hot water supply pipe  112   a , the overall flow rate refers to a flow rate which is the sum of the mixing flow and the flow rate of heat exchanger and is equal to the flow rate of direct water introduced through the direct water inlet pipe  111   a , and the mixing rate refers to a ratio of the mixing flow rate to the overall flow rate. 
     In  FIG. 6  and Table 2, the temperature of the heat exchanger refers to a temperature of hot water measured at the heat exchanger temperature sensor  123 , the temperature of hot water refers to a temperature of hot water measured at the hot water temperature sensor  124 , and the temperature of direct water refers to a temperature of direct water measured at the direct water temperature sensor  121 . 
     When the overall flow rate is changed from 3 to 14, the mixing flow rate increases with the increase of the overall flow in the section where the overall flow rate changes from 3 to 4, however, in the section where the overall flow rate changes from 4 to 14, because the elastic member  134  of the pressure reducing valve  130  does not change any more after being compressed as in  FIG. 4 , the mixing flow rate is constantly maintained even when the overall flow rate increases. 
     On the contrary, the flow rate of the heat exchanger increases as the overall flow rate increases, the mixing rate decreases as the overall flow rate increases. 
     In this case, while the temperature of the direct water is kept constant at 20° C., the temperature of the heat exchanger decreases from 61.5° C. to 48° C. as the flow rate of direct water provided to the heat exchanger  140  increases. 
     Therefore, even when the overall flow increases from 3 to 14 as a user increases the hot water usage flow rate, the temperature of hot water provided to the user through the hot water supply pipe  112   b  is constantly maintained at 45° C. because the mixing rate decreases from 0.4 to 0.11. 
     On the contrary, even when the overall flow rate decreases from 14 to 3 as the user decreases the hot water usage flow rate, the temperature of hot water is constantly maintained at 45° C. because the mixing rate increases from 0.11 to 0.4. 
     When the pressure reducing valve  130  is installed on the bypass pipe  113  as described above, the mixing rate is changed because the flow rate of the pressure reducing valve  130  is inherently restricted in a certain manner even when the hot water usage flow rate of the user is changed, and therefore the temperature of hot water provided to the user is uniformly maintained. Thus, because controlling, for example, adjusting of the opening degree of the mixing valve conventionally, is not necessary, a configuration of an apparatus becomes simple, and the flow rate of the pressure reducing valve  130  is restricted at the same time as the hot water usage flow rate of the user is changed, thereby immediate responsiveness minimizes the temperature deviations of hot water. 
     A Second Embodiment 
       FIG. 7  is a schematic view illustrating a configuration of a hot water supply apparatus according to a second embodiment of the present invention. 
     While the first embodiment illustrates the case in which the pressure reducing valve  130  is applied to a water heater, a hot water supply apparatus  200  of the second embodiment illustrates a case in which a pressure reducing valve  230  is applied to a boiler. 
     The hot water supply apparatus  200  includes a main heat exchanger  241 , a heating supply pipe  214  for supplying heating water, a heating water supply temperature sensor  271  and a three-way valve  272  which are provided on the heating supply pipe  214 , a heating recycle water pipe  215  through which heating return water flows, a circulation pump  270  provided on the heating recycle water pipe  215 , and a heating water supply pipe for supplying hot water  216  which is connected to the three-way valve  272  in order to supply heating water to a heat exchanger for supplying hot water  240  by being connected between the heating supply pipe  214  and the heating recycle water pipe  215 , wherein the hot water supply apparatus has the same constitution as a boiler capable of heating and supplying hot water. 
     As a constitution for supplying hot water, a direct water inlet pipe  211 , a direct water temperature sensor  221 , a flow rate sensor  222 , a heat exchanger temperature sensor  223 , a hot water supply pipe  212 , a hot water temperature sensor  224 , a bypass pipe  213 , and a pressure reducing valve  230  are formed to have the same constitutions as in the first embodiment. 
     Modified Embodiment 
     In the above embodiments, a configuration in which an elastic member is provided inside the pressure reducing valves  130  and  230  so that the pressure is reduced because the shape of a cross section is deformed by supply pressure of the direct water is exemplified, however the present invention is not limited thereto, modifications with various structures are possible. 
     For example, a valve portion for blocking a flow path through which the direct water passes is elastically supported by a spring, and a function of a pressure reducing valve may be implemented by overcoming the elastic force of the spring according to the pressure of the direct water and varying the opening degree of the valve portion. 
     In this case, an elastic modulus may be adjusted such that an amount of compression by which the spring is compressed is restricted to a certain amount in consideration of the supply pressure of the direct water, or a stopper may be provided to limit a moving distance of the valve portion. 
     The present invention is not limited to the embodiments described above, and it should be obvious to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention. Such modified embodiments are within the scope of this invention.