JP6007390B2 - Flow rate detection unit and hot water supply system - Google Patents

Description

  The present invention relates to a flow rate detection unit and a hot water supply system.

  A hot water supply device for a bathtub or the like is provided with a flow rate detection device for detecting a flow rate of hot water dropped into the bathtub or a recirculation flow rate (see, for example, Patent Document 1). Such a flow rate detection device generally includes an impeller that rotates in response to a flow, and detects the flow rate from the number of rotations.

JP-A-10-185636

  Since the chasing usually takes place after a person bathes in the bathtub, the circulation flow is dirty with dirt such as skin and foreign matter such as hair. When such a foreign substance flows through the impeller for detecting the flow rate, the foreign matter may adhere to the rotating part or the movable part of the impeller, and the impeller may be fixed or locked.

  The present invention has been made in view of such problems, and one of its purposes is to provide a flow rate detection unit and a hot water supply system that are not easily affected by foreign matter.

  In order to solve the above problems, an aspect of the present invention is a differential pressure type flow rate detection unit for detecting a flow rate in a branch pipe. The branch pipe includes a first opening end, a second opening end, and a third opening end. The first opening end is an inlet of a target flow whose flow rate is to be detected, and at least the second opening end and the third opening end. One is the target flow outlet. The flow rate detection unit includes a throttle that generates a differential pressure in the target flow, and a differential pressure chamber that includes a movable member that is movable by the differential pressure. The restrictor is disposed between the second opening end and the third opening end so as to generate a differential pressure also in the flow flowing from the second opening end or the third opening end in the direction opposite to the target flow. Yes.

  According to this aspect, a unit incorporating a differential pressure type flow rate detection function is configured. Since this flow rate detection unit is a differential pressure type, the displacement of the movable member due to the differential pressure is taken out as an amount representing the flow rate. Since there is no need to have a movable part having a sliding part such as an impeller in the pipe of the detection target flow, a flow rate detection unit that is resistant to foreign matters can be provided.

  The flow rate detection unit is attached to the branch pipe, and a throttle is provided in the branch pipe. This restrictor is provided so as to generate a differential pressure in both the flow flowing from one opening end and the flow flowing from another opening end. Thus, these two types of flows can be detected by a single flow rate detection unit. Therefore, the flow rate detection system of the system can be configured at a lower cost compared to the case where a detector is individually installed in the piping circuit of the system in order to detect each flow.

  Another aspect of the present invention is a hot water supply system. This hot water supply system includes a circulation circuit for circulating hot water in a bathtub, a hot water supply pipe connected to the circulation circuit for supplying temperature-controlled hot water to the bathtub through the circulation circuit, and a circulation circuit and a hot water supply pipe. And a differential pressure type flow rate detection unit provided in the connecting portion. The flow rate detection unit includes a throttle that generates a differential pressure in the flow that flows from the hot water supply pipe to the circulation circuit, and a differential pressure chamber that includes a movable member that is movable by the differential pressure. The restrictor is disposed in the circulation circuit at the connection portion.

  According to this aspect, a hot water supply system incorporating a differential pressure type flow rate detection unit is provided. Since it is not necessary to have a movable part such as an impeller in the pipe of the detection target flow, it is possible to provide a hot water supply system including a flow rate detection unit that is resistant to foreign matter.

  The hot water supply system has a configuration in which hot water is supplied from the hot water supply pipe to the bathtub via the circulation circuit, and this flow rate detection unit is provided on the circulation circuit side at the connection between the hot water supply pipe and the circulation circuit. Therefore, the flow rate detection unit can detect each of the hot water supply flow and the circulation flow (for example, hot water filling and reheating). In a typical hot water system, separate detectors are provided to detect these two flows, whereas the flow detection system of the hot water system can be configured at low cost by unitizing the two functions. It becomes.

  ADVANTAGE OF THE INVENTION According to this invention, the flow volume detection unit and hot water supply system which are hard to receive to the influence of a foreign material can be provided.

1 is a system diagram illustrating a configuration of a hot water storage type hot water supply apparatus according to an embodiment of the present invention. It is sectional drawing showing the whole structure of the flow volume detection unit which concerns on an embodiment with this invention. It is sectional drawing showing the whole structure of the flow volume detection unit which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a system diagram showing a configuration of a hot water storage type hot water supply apparatus according to an embodiment of the present invention. The hot water supply apparatus of this embodiment includes a hot water storage unit 10 and a heat pump unit 12. The hot water storage unit 10 includes a hot water storage tank 14, piping for circulating or supplying hot water, a control valve for controlling the flow of hot water, a sensor for detecting the temperature and flow rate of the hot water, and the like. The “pipe” such as the following water supply pipe means a conduit through which a fluid can flow, and includes a flow path in the apparatus in addition to a member connecting the apparatus and components. The hot water supply device supplies hot water adjusted to an appropriate temperature by the hot water storage unit 10 to water supply equipment such as the bathtub 13 and the currant 15. The hot water supply apparatus includes a hot water supply circuit for dropping hot water sent from the hot water storage tank 14 and adjusted to an appropriate temperature into the bathtub 13, and a reheating circulation circuit for replenishing hot water stored in the bathtub 13.

  The low-temperature water supplied from the water supply is supplied to the hot water storage unit 10 through the water supply pipe 16. The water supply pipe 16 branches into a first water supply pipe 17, a second water supply pipe 18 and a third water supply pipe 19 in the hot water storage unit 10. Among these, the first water supply pipe 17 is connected to the lower part of the hot water storage tank 14. A boiling circulation circuit is formed between the hot water storage tank 14 and the heat pump unit 12. That is, the outlet pipe 20 connected to the lower part of the hot water storage tank 14 is connected to the heat pump unit 12, and the return pipe 22 connected to the heat pump unit 12 is connected to the upper part of the hot water storage tank 14. Note that low temperature water is supplied to the currant 15 through a water supply pipe 16 in a separate system from the hot water supply apparatus.

  With such a configuration, the hot water storage tank 14 is formed with a temperature stratification in which high-temperature water is present in the upper part, intermediate-temperature water in the middle part, and low-temperature water in the lower part. The cold / hot water accumulated in the lower part of the hot water storage tank 14 is subjected to heat exchange by the heat pump unit 12 to become high temperature water, and is returned to the hot water storage tank 14. The outlet pipe 20 is provided with a pump 23 for promoting circulation of hot water in such a boiling circulation circuit.

  The heat pump unit 12 includes a refrigeration cycle that uses carbon dioxide as a refrigerant. This refrigeration cycle includes a refrigerant circulation circuit including a compressor, a heat exchanger, an expansion valve, and an evaporator. However, since the configuration and operation thereof are known, a detailed description thereof will be omitted. The low-temperature water flowing through the above-described boiling circulation circuit is boiled up into the high-temperature water when passing through the heat exchanger.

  A reheating heat source circuit for reheating is also connected to the hot water storage tank 14. That is, the heating circuit 24 that connects the upper part and the lower part of the hot water storage tank 14 is provided, and the heat exchanger 70 and the pump 72 are provided in the middle thereof. The pump 72 is driven at the time of chasing. Thereby, the high-temperature water accumulated in the upper part of the hot water storage tank 14 is led to the heat exchanger 70, and heat exchange is performed with the hot water flowing through the circulation passage 82 on the bathtub 13 side. Hot water whose temperature has decreased due to heat exchange is returned to the hot water storage tank 14.

  On the other hand, a hot water supply pipe 25 for deriving high temperature water is connected to the upper part of the hot water storage tank 14. The hot water supply pipe 25 is branched into a first hot water supply pipe 26 and a second hot water supply pipe 28. The first hot water supply pipe 26 is connected to the second water supply pipe 18, and the second hot water supply pipe 28 is connected to the third water supply pipe 19. The high-temperature water flowing through each hot water supply pipe and the low-temperature water flowing through each water supply pipe are mixed at a connection portion (merging portion) of those pipes. The hot water having an appropriate temperature by mixing the high temperature water in the first hot water supply pipe 26 and the cold and hot water in the second water supply pipe 18 is supplied to the currant 15 such as a kitchen via the pipe 30. On the other hand, the hot water having an appropriate temperature by mixing the hot water in the second hot water supply pipe 28 and the cold and hot water in the third water supply pipe 19 is supplied to the bathtub 13 through the hot water supply pipe 32.

  A first mixing valve 36 is provided at a connection point between the first hot water supply pipe 26, the second water supply pipe 18 and the pipe 30. The first mixing valve 36 adjusts the mixing ratio between the high-temperature water supplied through the first hot water supply pipe 26 and the low-temperature water supplied through the second water supply pipe 18, and supplies hot water with an appropriate temperature to the pipe 30. To derive. A check valve 40 is provided upstream of the first mixing valve 36 in the first hot water supply pipe 26. A check valve 42 is provided on the upstream side of the first mixing valve 36 in the second water supply pipe 18. The pipe 30 is provided with a temperature sensor 48 and a flow sensor 50 from the upstream side. A control unit (not shown) acquires the temperature of the temperature sensor 48 and controls the opening degree of the first mixing valve 36 so as to be a hot water supply temperature set by a user with a remote controller (not shown). The check valve 40 prevents hot water from the junction from flowing back to the first hot water supply pipe 26 when hot water supply is stopped. The check valve 42 prevents hot water from the junction from flowing back to the second water supply pipe 18 when hot water supply is stopped.

  On the other hand, a second mixing valve 38 is provided at a connection point between the second hot water supply pipe 28, the third water supply pipe 19, and the hot water supply pipe 32. The second mixing valve 38 adjusts the mixing ratio between the high-temperature water supplied via the second hot water supply pipe 28 and the low-temperature water supplied via the third water supply pipe 19, so that the hot water supply water 32 has an appropriate temperature. Is derived. A check valve 44 is provided upstream of the second mixing valve 38 in the second hot water supply pipe 28. A check valve 46 is provided upstream of the second mixing valve 38 in the third water supply pipe 19. The hot water supply pipe 32 is provided with a temperature sensor 52 and a control valve unit 54 from the upstream side. A control unit (not shown) acquires the temperature of the temperature sensor 52 and controls the opening degree of the second mixing valve 38 so as to be a hot water supply temperature set by a user using a remote controller (not shown). The check valve 44 prevents hot water from the junction from flowing back to the second hot water supply pipe 28 when hot water supply is stopped. The check valve 46 prevents the hot water in the junction from flowing back to the third water supply pipe 19 when the hot water supply is stopped.

  A check valve 55, a pressure reducing valve 56, and a shutoff valve 58 are provided upstream of the branch point of the water supply pipe 16 with the first water supply pipe 17. The pressure reducing valve 56 appropriately reduces the pressure of the cold / hot water supplied through the water supply pipe 16. That is, pressure adjustment is appropriately performed so that the hot water storage tank 14 and the like are not damaged by water pressure. The shutoff valve 58 shuts off the water supply pipe 16 when predetermined hot water has accumulated in the hot water storage tank 14 and appropriately stops the supply of cold / hot water. The check valve 55 prevents back flow of hot water in the water supply pipe 16 when water supply to the hot water storage unit 10 is stopped.

  The control valve unit 54 is provided with a control valve 60, a check valve 62, an atmosphere release valve 64, and a check valve 66 from the upstream side. The control valve 60 is an electromagnetic valve, and permits or blocks the supply of hot water to the bathtub 13 by opening and closing the hot water supply pipe 32. The check valve 66 and the check valve 62 prevent the backflow of hot water from the bathtub 13 toward the hot water storage tank 14 in a stepwise manner. The atmosphere release valve 64 opens the space between the check valve 62 and the check valve 66 to the atmosphere in response to a pressure drop on the upstream side (primary side).

  That is, for example, when the bathtub 13 is installed at a position higher than the hot water storage unit 10, when the check valve 66 disposed on the side of the bathtub 13 has poor watertightness due to the biting of foreign matter, The sewage in the bathtub 13 flows back to the atmosphere release valve 64 through the check valve 66 due to the water head pressure. Even in such a case, since the sewage is discharged to the atmosphere by the atmosphere release valve 64, the sewage in the bathtub 13 can be prevented from flowing back to the hot water storage unit 10 and thus to the water supply.

  The hot water supply pipe 32 branches at a branch point P on the downstream side of the control valve unit 54 into a connection passage 80 directly connected to the bathtub 13 and a circulation passage 82 forming a recirculation circuit. A flow rate detection unit 100 is provided at the branch point P. The flow rate detection unit 100 is a branch pipe with a flow sensor, as will be described in detail later.

  A pump 84 is provided in the connection passage 80, and a heat exchanger 70 is provided in the middle of the circulation passage 82. The pump 84 is driven only when reheating. That is, when filling the bathtub 13 with hot water, the control valve 60 is opened, and hot water adjusted to an appropriate temperature by the second mixing valve 38 is supplied. The hot water branches at a branch point P, and is supplied to the bathtub 13 through the connection passage 80 on the one hand and to the bathtub 13 through the circulation passage 82 on the other hand, as indicated by the solid arrow in the figure. However, since the pump 72 is not driven at the time of hot water filling, reheating is not performed. The amount of hot water supplied during hot water filling is calculated based on the detection value of the flow rate detection unit 100. When the supply of hot water of a predetermined flow rate is completed, the control valve 60 is closed and hot water filling is stopped.

  On the other hand, the pumps 72 and 84 are driven at the time of reheating. As a result, as indicated by a dotted arrow in the figure, hot water in the bathtub 13 is sent out toward the heat exchanger 70 and circulates in the recirculation circuit. The cooled hot water discharged from the bathtub 13 is heat-exchanged by the heat exchanger 70 to be heated, and returned to the bathtub 13 again. By this reheating, the hot water in the bathtub 13 is warmed to an appropriate temperature. In addition, since the control valve 60 is closed and the check valve 66 is maintained in the closed state at the time of reheating, the sewage in the bathtub 13 does not flow back to the hot water supply pipe 32. The circulation flow rate or presence or absence is detected based on the detection value of the flow rate detection unit 100. When the accumulated water amount of the bathtub is calculated, it is possible to obtain a guide for the renewal end time.

  Next, a specific configuration of the flow rate detection unit 100 will be described. FIG. 2 is a cross-sectional view illustrating the overall configuration of the flow rate detection unit 100. In the following description, for the sake of convenience, the positional relationship of members may be expressed with reference to the illustrated state. However, it should be noted that the expression of the positional relationship does not mean that the flow rate detection unit 100 is installed in the field in the specific direction illustrated. In other words, for example, the flow rate detection unit 100 may be installed in the direction opposite to the illustrated direction (that is, with the upper portion in the figure facing downward) or rotated by 90 degrees from the illustrated direction. It can also be installed in the orientation.

  The flow rate detection unit 100 includes a branch pipe 102 and a flow rate sensor unit 104. The branch pipe 102 is a T-shaped pipe joint and includes a first opening end 106, a second opening end 108, and a third opening end 110. Each of these open ends is a connection port for connecting the branch pipe 102 to another pipe. The flow sensor unit 104 is attached to the central portion of the branch pipe 102, in other words, the branch portion. The flow rate sensor unit 104 is configured to detect the flow rate of the branch pipe 102 based on the displacement of the movable member 126 due to the differential pressure.

  The first open end 106 is connected to the end of the hot water supply pipe 32 on the bathtub 13 side. As described with reference to FIG. 1, the hot water supply pipe 32 replenishes hot water stored in the bathtub 13 with a hot water supply circuit that drops hot water sent from the hot water storage tank 14 and adjusted to an appropriate temperature into the bathtub 13. It is a pipe connected to the circulation circuit. The second open end 108 is connected to the connection passage 80 of the recirculation circuit. The third open end 110 is connected to the circulation passage 82 of the recirculation circuit. In this way, the branch pipe 102 forms a connection portion between the circulation circuits 80 and 82 and the hot water supply pipe 32. A pipe line connecting the second opening end 108 and the third opening end 110 of the branch pipe 102 is a part of a circulation circuit for reheating.

  The branch pipe 102 includes a main pipe having a second open end 108 at one end and a third open end 110 at the other end, and a branch portion 112 in the middle of the main pipe. The main pipe includes a second pipe part 116 that is a part that connects the second open end 108 to the branch part 112, and a third pipe part 118 that is a part that connects the third open end 110 to the branch part 112. . The main pipe linearly extends from the second opening end 108 to the third opening end 110 through the second pipe portion 116, the branch portion 112, and the third pipe portion 118. As shown in the drawing, both the second tube portion 116 and the third tube portion 118 have a step portion in the middle, and the inner portion closer to the branch portion 112 than the step portion has a channel diameter slightly smaller than the outer portion.

  The branch pipe 102 includes a first pipe portion 114 having a branch portion 112 as a base end and a first opening end 106 at the end. The first pipe part 114 is a branch pipe branched from the main pipe including the second pipe part 116 and the third pipe part 118. The first pipe portion 114 branches in a right angle direction from the center of the main pipe and extends linearly. The first pipe portion 114 also has a step portion in the middle, and the inner portion closer to the branch portion 112 than the step portion has a channel diameter slightly smaller than the outer portion.

  The branch pipe 102 forms a flow path symmetrical to the left and right with respect to the pipe axis of the first pipe portion 114. Accordingly, the second pipe portion 116 and the third pipe portion 118 have the same diameter and length. The first pipe portion 114 may also have the same diameter and length as those.

  The branch pipe 102 includes a first orifice plate 120 and a second orifice plate 122. The first orifice plate 120 is provided between the branch portion 112 and the second opening end 108. A first orifice 121 is formed in the first orifice plate 120. More specifically, the first orifice plate 120 is disposed at the entrance from the branch portion 112 to the second pipe portion 116. The first orifice plate 120 is integrally formed with the branch pipe 102 as an annular convex portion protruding from the inner wall of the second pipe portion 116 toward the pipe axis. The first orifice 121 is a constricted portion formed coaxially with the tube axis of the second tube portion 116 by this annular convex portion.

  The second orifice plate 122 is between the branch portion 112 and the third opening end 110, and the second orifice plate 122 is formed with the second orifice 123. More specifically, the second orifice plate 122 is disposed at the entrance from the branch portion 112 to the third pipe portion 118. The second orifice plate 122 is integrally formed with the branch pipe 102 as an annular convex portion protruding from the inner wall of the third pipe portion 118 toward the pipe axis. The second orifice 123 is a constricted portion formed coaxially with the tube axis of the third tube portion 118 by the annular convex portion.

  In this way, the first orifice 121 flows upstream and downstream of the first orifice 121 in a flow (for example, pouring from the hot water supply pipe 32) flowing in from the first opening end 106 and flowing out from the second opening end 108. Is arranged in the branch pipe 102 so as to generate a differential pressure therebetween. At this time, the upstream side of the first orifice 121 (that is, the first pipe portion 114 and the branch portion 112) becomes high pressure, and the downstream side of the first orifice 121 (that is, the second pipe portion 116) becomes low pressure.

  Conversely, the first orifice 121 branches so as to generate a differential pressure between the upstream side and the downstream side of the first orifice 121 in the flow (for example, the recirculation circulation flow) flowing from the second opening end 108. It is arranged in the pipe 102. At this time, the upstream side of the first orifice 121 (that is, the second pipe portion 116) becomes high pressure, and the downstream side of the first orifice 121 (that is, the first pipe portion 114 and the branching portion 112) becomes low pressure.

  In addition, the second orifice 123 causes the branch pipe 102 to generate a differential pressure between the upstream side and the downstream side of the second orifice 123 in the flow flowing in from the first opening end 106 and flowing out from the third opening end 110. It is arranged. At this time, the upstream side of the second orifice 123 (that is, the first pipe portion 114 and the branch portion 112) becomes high pressure, and the downstream side of the second orifice 123 (that is, the second pipe portion 116) becomes low pressure. Similarly, the second orifice 123 generates a differential pressure between the upstream side and the downstream side of the second orifice 123 in the flow flowing in from the second opening end 108.

  The second orifice plate 122 is provided symmetrically with the first orifice plate 120 with respect to the tube axis of the first tube portion 114. The second orifice 123 has the same shape as the first orifice 121. As described above, the second tube portion 116 and the third tube portion 118 are formed symmetrically. Therefore, the branch pipe 102 is configured such that the flow flowing from the first opening end 106 is equally divided into the second opening end 108 and the third opening end 110. Or the 2nd orifice 123 may be formed in the opening shape different from the 1st orifice 121 so that the difference in the pressure loss of the exterior (for example, the connection channel 80 and the circulation channel 82) of the branch piping 102 may be compensated. .

  The flow sensor unit 104 includes a differential pressure chamber 124, a movable member 126 that can be moved by the differential pressure, and a magnetic sensor 128 that detects the flow rate in the branch pipe 102 based on the position of the movable member 126. The movable member 126 is disposed so as to be movable in the tube axis direction of the first tube portion 114. The magnetic sensor 128 includes a magnet 130 such as a permanent magnet and a magnetic detection element 132. Although described in detail later, the magnet 130 is attached to the movable member 126 so as to be movable integrally with the movable member 126. The magnetic detection element 132 is attached to the sensor housing 134.

  The differential pressure chamber 124 includes a first pressure chamber 136 and a second pressure chamber 138. The first pressure chamber 136 is formed between the branch pipe 102 and the movable member 126, and the second pressure chamber 138 is formed between the movable member 126 and the sensor housing 134. In this way, the differential pressure chamber 124 is partitioned into the first pressure chamber 136 and the second pressure chamber 138 by the movable member 126.

  The differential pressure chamber 124 is a compartment defined by the branch pipe 102 and the sensor housing 134. The sensor housing 134 is fixed to the branch pipe 102 so that its internal space is adjacent to the outside of the central pipe wall 140 of the branch pipe 102. The central tube wall 140 is a portion of the branch pipe 102 that forms the branch portion 112 inside thereof. On the outer peripheral side from the central tube wall 140, thick portions are formed on the tube wall lower side of the second tube portion 116 and the third tube portion 118. This thick portion forms an annular platform 142 for fixing the sensor housing 134 to the branch pipe 102. The sensor housing 134 is attached to the annular base 142 of the branch pipe 102 in a watertight manner.

  The movable member 126 includes a diaphragm 144 and a magnet holding part 146. The outermost peripheral portion of the diaphragm 144 is fixed, and the thin outer peripheral portion on the inside thereof has a portion curved downwardly in a convex shape. The thin outer peripheral portion has a thickened portion on the upper surface side, and further has a concave portion on the lower surface for receiving the upper end portion of the magnet holding portion 146 at the inner central portion. The outermost peripheral part of the diaphragm 144 is sandwiched and fixed between the annular base part 142 of the branch pipe 102 and the sensor housing 134. A thin outer peripheral portion of the diaphragm 144 can be deformed by a differential pressure between the first pressure chamber 136 and the second pressure chamber 138. The center of the diaphragm 144 is on the tube axis of the first pipe portion 114 of the branch pipe 102, and the diaphragm 144 is disposed so as to intersect the tube axis perpendicularly.

  Thus, the first pressure chamber 136 is formed between the outer surface of the central tube wall 140 of the branch pipe 102 and the inner surface of the annular platform 142 and the upper surface of the diaphragm 144. FIG. 2 shows the initial position of the movable member 126 when no differential pressure is acting on the differential pressure chamber 124. At this time, the diaphragm 144 is away from the branch pipe 102, and there is a distance A between them. This distance A is provided so that the movable member 126 can be moved upward from the initial position.

  The magnet holding portion 146 is a member having a columnar shape extending along the tube axis of the first tube portion 114. A diaphragm mounting portion 148 and a spring mounting portion 150 are provided on the upper end portion of the magnet holding portion 146 in order from the top in the axial direction. There is an annular groove between the diaphragm mounting portion 148 and the spring mounting portion 150. The diaphragm attachment portion 148 is attached to the lower surface of the center portion of the diaphragm 144 by bonding or the like.

  One end of a spring 152 is attached to the outer peripheral portion of the lower surface of the spring mounting portion 150, and the other end of the spring 152 is attached to a portion of the sensor housing 134 that faces the outer peripheral portion of the lower surface of the spring mounting portion 150. The spring 152 is provided to elastically support the movable member 126 at the initial position, and an arbitrary elastic member may be used instead of the spring 152.

  An extending portion 154 extends from the center of the lower surface of the spring mounting portion 150 downward through the inside of the spring 152. A magnet 130 of the magnetic sensor 128 is fixed to the lower end of the extending portion 154. The sensor housing 134 has a housing recess 156 that receives the extension 154, and the extension 154 is loosely inserted into the housing recess 156. The magnetic detection element 132 of the magnetic sensor 128 is accommodated in the lower end portion of the housing recess 156. The magnetic detection element 132 is configured to give an output corresponding to the distance between the element and the magnet 130.

  A stepped portion whose diameter is increased outward is formed at the upper end of the housing recess 156, and the other end of the spring 152 is attached to the stepped portion. Further, the inner space of the sensor housing 134 is further expanded from the stepped portion to the outside, thereby forming the bottom wall and the side wall of the second pressure chamber 138. Thus, the second pressure chamber 138 is formed between the lower surface of the diaphragm 144 and the sensor housing 134.

  In the initial position shown in the figure, the lower end of the extension portion 154 is separated from the bottom portion of the housing recess 156 (accommodating portion of the magnetic detection element 132), and there is a distance B between them. This distance B is provided so that the movable member 126 can be moved downward from the initial position. In addition, a gap between the lower surface of the spring mounting portion 150 and the bottom wall of the second pressure chamber 138 is also provided to enable the movable member 126 to move downward from the initial position.

  The flow rate detection unit 100 also includes a first pressure introduction path 158 and a second pressure introduction path 160 for introducing a differential pressure from the branch pipe 102 to the differential pressure chamber 124. The first pressure introduction path 158 is formed so as to penetrate the central tube wall 140 of the branch portion 112, and connects the branch portion 112 to the first pressure chamber 136. The first pressure introduction path 158 introduces the pressure of the branch portion 112 into the first pressure chamber 136. A first orifice 121 is provided on one side of the first pressure introduction path 158, a second orifice 123 is provided on the opposite side, and the first pressure introduction path 158 is sandwiched between the first orifice 121 and the second orifice 123. Is connected to the branch pipe 102.

  The second pressure introduction path 160 is formed so as to penetrate the annular base portion 142 of the second tube portion 116 and the sensor housing 134, and connect the second tube portion 116 to the second pressure chamber 138. The second pressure introduction path 160 introduces the pressure of the second pipe portion 116 into the second pressure chamber 138. A seal portion 162 is provided between the annular base portion 142 of the second tube portion 116 and the sensor housing 134 to keep the second pressure introduction path 160 watertight.

  In this way, the first pressure introduction path 158 connects the branch portion 112 side, which is one side of the first orifice 121, to the first pressure chamber 136. The second pressure introduction path 160 connects the second opening end 108 side which is the other side of the first orifice 121 to the second pressure chamber 138.

  Accordingly, the first pressure introduction path 158 introduces the upstream pressure of the first orifice 121 into the first pressure chamber 136 when the flow flows from the first opening end 106, while the flow flows from the second opening end 108. The downstream pressure of the first orifice 121 is introduced into the first pressure chamber 136. The second pressure introduction path 160 introduces the downstream pressure of the first orifice 121 into the first pressure chamber 136 when the flow flows from the first opening end 106, while the flow flows from the second opening end 108. The upstream pressure of the first orifice 121 is introduced into the first pressure chamber 136.

  Next, the operation of the flow rate detection unit 100 will be described with reference to FIGS. 1 and 2. In the following, in order not to make the description unnecessarily complicated in understanding the movement of the movable member 126, the upstream pressure of the orifice is uniformly expressed as P, and the pressure difference generated before and after the orifice by ΔP is expressed as ΔP. Write uniformly. Actually, the magnitude of the upstream pressure of the orifice may be different between the hot water supply flow and the circulation flow, and the pressure difference generated between the first orifice 121 and the second orifice 123 may be different, but the movement of the movable member 126 is basically the same. The flow rate detection unit 100 is designed to be as described below.

  First, when hot water whose temperature is adjusted is supplied from the hot water supply pipe 32 to the bathtub 13 through the branch pipe 102, the hot water flows from the hot water supply pipe 32 into the branch pipe 102 through the first opening end 106, It branches to the 3rd opening end 110, and flows out from the branch piping 102. The flow through the second opening end 108 is supplied to the bathtub 13 through the connection passage 80, and the flow through the third opening end 110 is supplied to the bathtub 13 through the circulation passage 82.

  At this time, the pressure in the first pipe portion 114 and the branch portion 112 of the branch pipe 102 is the orifice upstream pressure P. Since the pressure difference ΔP is generated by the first orifice 121 on the downstream side of the first orifice 121 (that is, the second pipe portion 116), the pressure becomes P−ΔP. Also on the downstream side of the second orifice 123 (that is, the third pipe portion 118), a pressure difference ΔP is generated by the second orifice 123, and becomes a pressure P−ΔP.

  The orifice upstream pressure P is introduced from the branch portion 112 into the first pressure chamber 136 through the first pressure introduction path 158. On the other hand, the orifice downstream pressure P-ΔP is introduced from the second pipe portion 116 into the second pressure chamber 138 through the second pressure introduction path 160. In this way, the first pressure chamber 136 becomes the high pressure P and the second pressure chamber 138 becomes the low pressure P−ΔP, so that the differential pressure ΔP acts on the diaphragm 144.

  Since the first pressure chamber 136 is at a high pressure, the diaphragm 144 is deformed so as to increase the volume of the first pressure chamber 136, thereby moving the movable member 126 downward. The movable member 126 stops at a balance position of the force acting by the differential pressure ΔP, the elastic force of the diaphragm 144, and the elastic force of the spring 152. Therefore, the magnet 130 of the magnetic sensor 128 is displaced downward from the initial position to the balanced position, and the distance between the magnet 130 and the magnetic detection element 132 is reduced. The magnetic sensor 128 outputs an electrical signal indicating the position of the magnet 130, that is, the movable member 126.

  The relationship between the total flow rate passing through the branch pipe 102 and the branch flow rate passing through the first orifice 121, the relationship between the branch flow rate and the differential pressure ΔP generated in the differential pressure chamber 124, and the relationship between the differential pressure ΔP and the stop position of the movable member 126. The relationship between the stop position and the magnetic sensor output signal can be determined in advance. Therefore, the flow rate detection unit 100 can calculate the flow rate in the branch pipe 102 by a flow rate calculation unit (not shown) based on the output signal obtained from the magnetic sensor 128. The flow rate detection unit 100 can also determine the amount of pouring water into the bathtub 13 by integrating the flow rate of the branch pipe 102. The flow rate detection unit 100 outputs the flow rate of the branch pipe 102 or its integrated amount to the outside or the control unit of the hot water supply device as necessary.

  The flow rate detection unit 100 calculates the branch flow rate on the first orifice 121 side based on the position of the movable member 126, calculates the branch flow rate on the second orifice 123 side based on the calculation result, and adds them to branch. The total flow rate passing through the pipe 102 is obtained. The flow rate detection unit 100 may calculate the branch flow rate based on, for example, the pressure loss ratio of the external pipe (for example, the pipes 80 and 82). Therefore, the flow rate detection unit 100 can detect not only the total flow rate of the branch pipe 102 but also each branched hot water amount with a single sensor.

  On the other hand, when the hot water in the bathtub 13 is circulated, the hot water flows from the bathtub 13 through the connection passage 80 into the branch pipe 102 from the second opening end 108, flows out from the third opening end 110 into the circulation passage 82, and is heated. Return to the bathtub 13. Since the control valve unit 54 has the check valves 62 and 66, the hot water flowing into the branch pipe 102 does not flow out to the first opening end 106 and the hot water supply pipe 32 side.

  At this time, the pressure in the second pipe portion 116 of the branch pipe 102 is the orifice upstream pressure P. As the flow passes through the first orifice 121, the pressure in the first pipe portion 114 and the branch portion 112 becomes P−ΔP. Further, when the flow passes through the second orifice 123, the pressure in the third pipe portion 118 becomes P-2ΔP.

  The orifice upstream pressure P is introduced from the second pipe portion 116 into the second pressure chamber 138 through the second pressure introduction path 160. On the other hand, the orifice downstream pressure P−ΔP is introduced into the first pressure chamber 136 from the branch portion 112 through the first pressure introduction path 158. Thus, contrary to the case of pouring, the first pressure chamber 136 becomes the low pressure P−ΔP, the second pressure chamber 138 becomes the high pressure P, and the differential pressure ΔP acts on the diaphragm 144.

  Since the second pressure chamber 138 is at a high pressure, the diaphragm 144 is deformed so as to increase the volume of the second pressure chamber 138, whereby the movable member 126 moves upward to a balance position between the differential pressure and the elastic force. Stop. The magnet 130 is displaced upward from the initial position, and the distance between the magnet 130 and the magnetic detection element 132 is increased. The flow rate detection unit 100 calculates a flow rate in the branch pipe 102 by a flow rate calculation unit (not shown) based on an output signal obtained from the magnetic sensor 128. The flow rate detection unit 100 can also obtain the circulation integrated water amount of the bathtub 13 by integrating the calculated flow rate. The flow rate detection unit 100 outputs the circulating flow rate or the integrated amount thereof to the outside or the control unit of the hot water supply device as necessary.

  As described above, in the flow rate detection unit 100, the moving direction of the movable member 126 is changed depending on the flow direction. In other words, the range that the output value of the magnetic sensor 128 can take changes depending on the flow direction, with the initial value corresponding to the initial position of the movable member 126 as a boundary. Therefore, the flow rate detection unit 100 can determine the flow direction based on the output signal of the magnetic sensor 128. In this way, the flow rate detection unit 100 can also identify whether the flow to be detected is pouring or circulation.

  As described above, according to the present embodiment, the two functions of measuring the amount of pouring water into the bathtub 13 and detecting the circulation operation can be provided by one control component. In the existing water heater, a flow sensor for measuring the pouring amount and a flow switch for detecting the circulation operation are respectively provided, but various advantages can be obtained by unitization as in this embodiment. it can.

  For example, the reduction in the number of parts and the simplification of pipe connection by unitization lead to a reduction in the price of the entire water heater. In addition, the device can be reduced in size and weight. In the case where a flow switch is used for circulation operation detection, only the presence / absence of a flow is detected, whereas in this embodiment, the circulation flow rate can be detected. Furthermore, by adopting the configuration of the differential pressure type flow meter in the flow rate detection unit 100, it is not necessary to expose the rotating parts such as the impeller to the pipe line as in the past. Therefore, it is possible to provide the flow rate detection unit 100 having excellent resistance to foreign matters.

  FIG. 3 is a cross-sectional view illustrating the overall configuration of the flow rate detection unit 100 according to another embodiment. In this flow rate detection unit 100, unlike the one shown in FIG. 2, a second pressure introduction path 160 is provided in the third pipe portion 118. Therefore, as will be described later, the movable member 126 moves in the same direction between pouring and circulation. Since the other configurations are the same, the same portions are denoted by the same reference numerals, and redundant description is appropriately omitted to avoid redundancy.

  As already described, when hot water whose temperature is adjusted is supplied from the hot water supply pipe 32 to the bathtub 13 through the branch pipe 102, the pressure in the first pipe portion 114 and the branch portion 112 is the orifice upstream pressure P, and the third The pressure in the pipe portion 118 is the orifice downstream pressure P-ΔP. The orifice upstream pressure P is introduced from the branch portion 112 into the first pressure chamber 136 through the first pressure introduction path 158. On the other hand, the orifice downstream pressure P-ΔP is introduced from the third pipe portion 118 into the second pressure chamber 138 through the second pressure introduction path 160. Thus, when the first pressure chamber 136 becomes the high pressure P and the second pressure chamber 138 becomes the low pressure P−ΔP, the movable member 126 moves downward.

  When the hot water in the bathtub 13 is circulated, the hot water flows from the bathtub 13 through the connection passage 80 into the branch pipe 102 from the second opening end 108 and flows out from the third opening end 110 into the circulation passage 82. The second pipe portion 116 of the branch pipe 102 is at the pressure P, and the first pipe portion 114 and the branch portion 112 are at the pressure P−ΔP by passing through the first orifice 121, and the third portion by passing through the second orifice 123. The pipe part 118 is at a pressure P-2ΔP.

  At this time, the upstream pressure P-ΔP of the second orifice 123 is introduced into the first pressure chamber 136 from the branch portion 112 through the first pressure introduction path 158. On the other hand, the downstream pressure P-2ΔP from the second orifice 123 is introduced from the third pipe portion 118 into the second pressure chamber 138 through the second pressure introduction path 160. Thus, the first pressure chamber 136 becomes a high pressure P-ΔP, and the second pressure chamber 138 becomes a low pressure P-2ΔP. Therefore, the movable member 126 moves downward as in the case of pouring.

  In this embodiment, the movable range A in the first pressure chamber 136 may be eliminated. That is, the movable member 126 may be in contact with the central tube wall 140 of the branch pipe 102 at the initial position. Thereby, the initial position can be easily positioned. Further, the movable range B of the second pressure chamber 138 can be increased by the amount that the movable range A is eliminated. Thereby, the flow rate measurement range can be enlarged.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Nor.

  In the embodiment described above, the flow rate detection unit 100 includes at least one orifice 121, 123 in order to generate a differential pressure in the target flow whose flow rate is to be detected. However, such a differential pressure generating element is not limited to an orifice, and may be another restriction such as a flow nozzle or a venturi pipe, or any differential pressure generating element that generates a pressure difference before and after the element. In the flow rate detection unit 100, the differential pressure generated by the second orifice 123 is not introduced into the differential pressure chamber 124, so the flow rate detection unit 100 may not include the second orifice plate 122.

  In addition, the movable member for taking out the differential pressure in the differential pressure chamber 124 as a displacement is not limited to the diaphragm type as described above, and may include other pressure receiving displacement bodies such as a bellows and a piston, or move by the differential pressure. Any movable member that is possible may be used. The sensor for detecting the position of the movable member is not limited to the magnetic sensor 128, and may be another non-contact displacement sensor such as a capacitance type sensor or a contact type sensor.

  In the above embodiment, the sensor that detects the displacement amount of the movable member (magnet) that is displaced together with the diaphragm is shown. However, in another embodiment, instead of the sensor for detecting the position of the movable member, the movable member You may provide the sensor for detecting the force which acts. For example, the flow rate detection unit may use a pressure sensor that senses a differential pressure from distortion of the pressure-sensitive member. Thus, the differential pressure acting on the movable member may be directly detected. Specifically, for example, a strain gauge is attached to one side surface of the diaphragm 144 shown in FIG. 2 (for example, the surface on the first pressure chamber 136 side), and according to the differential pressure between the first pressure chamber 136 and the second pressure chamber 138. Alternatively, a detection signal corresponding to the distortion (deformation amount) of the diaphragm 144 may be output. In this case, the pressure-sensitive member is not limited to a diaphragm, and may be a member that deforms due to a differential pressure to cause distortion. Needless to say, various sensors (differential pressure detection sensors) can be used as long as the differential pressure between the first pressure chamber 136 and the second pressure chamber 138 can be detected.

  In the above embodiment, the pressure introduction paths 158 and 160 for introducing the differential pressure from the branch pipe 102 to the differential pressure chamber 124 are formed along the plane including the pipe axis of the branch pipe 102. I can't. The central axis of the pressure introduction path may deviate from the tube axis surface, and for example, the pressure introduction path may be formed orthogonal to the tube axis surface. In this case, the flow sensor unit is provided on the near side or the far side with respect to the paper surface of FIG.

  In the above embodiment, the branch pipe 102 is a three-pronged branch pipe having three open ends, but the flow rate detection unit 100 can also be applied to a different branch pipe. For example, a branch pipe having four open ends (for example, a cross pipe) or a branch pipe having a larger number of open ends may be used.

  In the above embodiment, the first open end 106 of the branch pipe 102 is connected to the hot water supply pipe 32, the second open end 108 and the third open end 110 are connected to the circulation circuit, and the circulation circuit is a straight pipe of the branch pipe 102. Through the department. However, the connection relationship between the hot water supply circuit and the circulation circuit is not limited to this. For example, hot water supply water is supplied so that the flow of dropping from the hot water supply pipe 32 to the bathtub 13 passes through the straight pipe portion of the branch pipe 102 and the recirculation circulation flow passes through one side of the straight pipe portion and the branch pipe branched from the straight pipe portion. The circuit and the circulation circuit may be connected. In this case, at least one throttle for generating a differential pressure in the flow may be provided in the pipe of the circulating flow. Moreover, the drop flow may not be a branch flow that flows out from a plurality of outlets of the branch pipe, and for example, the hot water supply system may be configured to flow out from only one outlet to the bathtub.

  The flow rate detection unit 100 according to the present embodiment can be attached not only to the hot water supply system but also to other piping systems.

  In addition, this invention is not limited to the said embodiment and modification, A component can be deform | transformed and embodied in the range which does not deviate from a summary. Various inventions may be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments and modifications. Moreover, you may delete some components from all the components shown by the said embodiment and modification.

  The flow rate detection unit and the hot water supply system according to the present invention can be conceptually understood as follows.

  According to an aspect of the present invention, a differential pressure type flow rate detection unit for detecting a flow rate in a branch pipe is provided. The branch pipe includes a first opening end, a second opening end, and a third opening end. The first open end is an inlet of a target flow whose flow rate is to be detected. At least one of the second open end and the third open end is an outlet of the target flow. The flow rate detection unit includes a throttle that generates a differential pressure in the target flow, and a differential pressure chamber that includes a movable member that is movable by the differential pressure. The restrictor generates a pressure difference between the second opening end and the third opening end in a direction opposite to the target flow so as to generate a differential pressure with respect to the flow flowing from the second opening end or the third opening end. It is arranged in between.

  The differential pressure chamber may be partitioned into a first chamber and a second chamber by the movable member. The flow rate detection unit connects one side of the throttle and the first chamber, a first pressure introduction path for introducing the upstream pressure of the target flow into the first chamber, and the other side of the throttle And a second pressure introduction path for connecting the second chamber and introducing the downstream pressure of the target flow into the second chamber. In the flow rate detection unit, the upstream pressure of the flow flowing in from the second opening end is introduced into the second chamber from the other side of the throttle by the second pressure introduction path, and the flow flowing in from the second opening end A downstream pressure may be introduced into the first chamber from one side of the throttle by the first pressure introduction path.

  The differential pressure chamber may be partitioned into a first chamber and a second chamber by the movable member. The flow rate detection unit connects one side of the throttle and the first chamber, a first pressure introduction path for introducing the upstream pressure of the target flow into the first chamber, and the other side of the throttle And a second pressure introduction path for connecting the second chamber and introducing the downstream pressure of the target flow into the second chamber. In the flow rate detection unit, the upstream pressure of the flow flowing in from the second opening end is introduced into the first chamber from one side of the throttle by the first pressure introduction path, and the flow flowing in from the second opening end A downstream pressure may be introduced into the second chamber from the other side of the throttle by the second pressure introduction path.

  The throttle may include an orifice formed inside the branch pipe. The movable member may include a diaphragm whose outer periphery is supported by the differential pressure chamber, and a magnet that is provided so as to be movable integrally with a central portion of the diaphragm. The flow rate detection unit may further include a magnetic sensor for detecting the position of the magnet.

  A hot water supply system includes a circulation circuit for circulating hot water in a bathtub, a hot water supply pipe connected to the circulation circuit for supplying temperature-controlled hot water to the bathtub through the circulation circuit, and the flow rate detection unit. , May be provided. The first opening end may be connected to the hot water supply pipe, and the second opening end and the third opening end may be connected to the circulation circuit.

  According to an aspect of the present invention, a circulation circuit for circulating hot water in a bathtub, a hot water supply pipe connected to the circulation circuit for supplying temperature-controlled hot water to the bathtub through the circulation circuit, There is provided a hot water supply system including a differential pressure type flow rate detection unit provided at a connection portion between a circulation circuit and the hot water supply pipe. The flow rate detection unit includes a throttle that generates a differential pressure in a flow that flows from the hot water supply pipe to the circulation circuit, and a differential pressure chamber that includes a movable member that is movable by the differential pressure. The throttle is disposed in the circulation circuit at the connecting portion.

  The flow rate detection unit detects the supply amount of hot water based on the position of the movable member when supplying hot water from the hot water supply pipe to the bathtub, while the movable member circulates hot water in the bathtub in the circulation circuit. The flow rate or presence or absence of circulation may be detected based on the position.

  13 Bath, 32 Hot water supply pipe, 80 Connection passage, 82 Circulation passage, 100 Flow rate detection unit, 102 Branch pipe, 104 Flow rate sensor part, 106 First opening end, 108 Second opening end, 110 Third opening end, 121 First Orifice, 123 Second orifice, 124 Differential pressure chamber, 126 Movable member, 128 Magnetic sensor, 130 Magnet, 136 First pressure chamber, 138 Second pressure chamber, 144 Diaphragm, 158 First pressure introduction path, 160 Second pressure introduction Road.

Claims (5)

A differential pressure type flow rate detection unit for detecting the flow rate in a branch pipe,
The branch pipe includes a first opening end, a second opening end, and a third opening end, and the first opening end is an inlet of a target flow whose flow rate is to be detected, and the second opening end and the third opening end. At least one of the open ends is an outlet of the target flow;
The flow rate detection unit includes:
A throttle that creates a differential pressure in the target flow;
A differential pressure chamber including a movable member movable by the differential pressure,
The restrictor generates a pressure difference between the second opening end and the third opening end in a direction opposite to the target flow so as to generate a differential pressure with respect to the flow flowing from the second opening end or the third opening end. A flow rate detection unit characterized by being disposed between. The differential pressure chamber is partitioned into a first chamber and a second chamber by the movable member,
The flow rate detection unit includes:
A first pressure introduction path for connecting one side of the throttle and the first chamber, and introducing an upstream pressure of the target flow into the first chamber;
A second pressure introduction path for connecting the other side of the throttle to the second chamber and introducing a downstream pressure of the target flow into the second chamber;
The upstream pressure of the flow flowing in from the second opening end is introduced into the second chamber from the other side of the throttle by the second pressure introduction path, and the downstream pressure of the flow flowing in from the second opening end is the first pressure. 2. The flow rate detection unit according to claim 1, wherein the flow rate detection unit is introduced into the first chamber from one side of the throttle by a pressure introduction path. The differential pressure chamber is partitioned into a first chamber and a second chamber by the movable member,
The flow rate detection unit includes:
A first pressure introduction path for connecting one side of the throttle and the first chamber, and introducing an upstream pressure of the target flow into the first chamber;
A second pressure introduction path for connecting the other side of the throttle to the second chamber and introducing a downstream pressure of the target flow into the second chamber;
The upstream pressure of the flow flowing in from the second opening end is introduced into the first chamber from one side of the throttle by the first pressure introduction path, and the downstream pressure of the flow flowing in from the second opening end is the second pressure. The flow rate detection unit according to claim 1, wherein the flow rate detection unit is introduced into the second chamber from the other side of the throttle by a pressure introduction path. The throttle includes an orifice formed inside the branch pipe,
The movable member includes a diaphragm whose outer periphery is supported by the differential pressure chamber, and a magnet provided so as to be movable integrally with a central portion of the diaphragm,
The flow rate detection unit according to any one of claims 1 to 3, wherein the flow rate detection unit further includes a magnetic sensor for detecting a position of the magnet. A hot water system,
A circulation circuit for circulating hot water in the bathtub;
A hot water supply pipe connected to the circulation circuit to supply conditioned hot water to the bathtub through the circulation circuit;
A flow rate detection unit according to any one of claims 1 to 4,
The hot water supply system, wherein the first open end is connected to the hot water supply pipe, and the second open end and the third open end are connected to the circulation circuit.

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