JP2021139664A - Detection unit - Google Patents

Abstract

To provide a detection unit that is hardly affected by a foreign matter entering from outside while maintaining good detection performance.SOLUTION: A detection unit 68 includes an inner cylinder 136 that forms a double pipe structure with a body 91 at a position of a connection point 111 between a first flow passage 105 and a second flow passage 109. A rotor is provided on an upstream side with respect to the connection point 111 in the first flow passage 105. An annular passage 138 for swirling a fluid flowing into the connection point 111 from an upstream side of the second flow passage 109 around an axial line L1 of the first flow passage 105 is formed between an inner peripheral surface of the body 91 and an outer peripheral surface of the inner cylinder 136. A plurality of guide sections 150 protruding from the inner cylinder 136 toward a downstream side of the first flow passage 105 is provided. The plurality of guide sections 150 is provided at intervals around an opening end 139 of the inner cylinder 136 and extended to the downstream side of the first flow passage 105 with respect to the opening end 139 of the inner cylinder 136.SELECTED DRAWING: Figure 2

Description

The present invention relates to a detection unit for detecting a flow state of a fluid flowing through a pipe.

A hot water supply system is generally provided with a drop-in hot water supply channel for dropping hot water adjusted to an appropriate temperature into a bathtub, and a reheating circulation circuit for reheating the hot water stored in the bathtub. In such a hot water supply system, a flow sensor is provided in the drop hot water supply passage and the reheating circulation circuit to detect the flow rate and circulation of hot water. It is also known that a common flow rate detection unit is provided at the connection portion between the drop-in hot water supply channel and the reheating circulation circuit (see, for example, Patent Document 1). Such a flow rate detecting unit generally includes a rotating body that rotates in response to the flow, and detects the flow rate from the rotation speed.

The body of the flow rate detection unit described in Patent Document 1 is provided with a first flow path forming a drop-in hot water supply path and a second flow path forming a reheating circulation circuit. The second flow path is connected in the middle of the first flow path. The rotating body is arranged on the upstream side of the connection point with the second flow path in the first flow path. An inner cylinder is provided at the position of the connection point in the first flow path, and a double pipe structure is formed. Hot water flowing into the connection point from the upstream side of the second flow path is swirled by guiding it to an annular passage formed between the inner peripheral surface of the body and the outer peripheral surface of the inner cylinder. As a result, a vortex that swirls around the axis is induced on the upstream side of the connection point in the first flow path, and the rotation of the rotating body is promoted.

Japanese Unexamined Patent Publication No. 2017-09349

By the way, in order to effectively exert the function of such a vortex-inducing structure, a swirling flow of hot water is sufficiently generated at the connection point, and the vortex flow due to the swirling flow is generated in the first flow path through the internal passage of the inner cylinder. It must be efficiently communicated to the upstream side. In this regard, since the inner cylinder itself can be a barrier to vortex transmission, it is possible to minimize the height of the inner cylinder. However, if the hot water flowing into the second flow path contains a foreign substance, it may be drawn into the rotating body side along with the transmission of the vortex flow. According to the verification by the inventors, it was found that a light and long fibrous foreign substance such as hair tends to be guided to the open end of the inner cylinder while floating along the swirling flow. If such a foreign substance wraps around the shaft of the rotating body or enters the bearing thereof, there is a risk that the flow rate detection will be hindered.

The present invention has been made in view of such a problem, and one of the objects thereof is to provide a detection unit which is not easily affected by foreign matter invading from the outside while maintaining good detection performance. ..

One aspect of the present invention is a detection unit for detecting the flow state of a fluid. This detection unit has a body provided with a linear first flow path and a second flow path connected in the middle of the first flow path, and a rotation axis extending along the first flow path. A rotating body that has and rotates according to the flow of fluid passing through the first flow path and is provided on the upstream side of the opening to the connection point between the second flow path and the second flow path in the first flow path, and has a rotation axis. The bearing part that rotatably supports, the detection part for detecting the rotational state of the rotating body, and the fluid from the upstream side to the connection point in the second flow path are biased to one side with respect to the axis of the first flow path. A vortex-inducing structure that generates a vortex that swirls around its axis on the upstream side of the connection point in the first flow path by guiding it to a position, and an axial direction toward the downstream side of the bearing along the first flow path. It is provided with an inner cylinder that extends to the body and forms a double-tube structure with the body at the position of the connection point.

An annular passage is formed between the inner peripheral surface of the body and the outer peripheral surface of the inner cylinder to swirl the fluid flowing into the connection point from the upstream side of the second flow path around the axis of the first flow path. A plurality of guide portions projecting from the inner cylinder toward the downstream side of the first flow path are provided. The plurality of guide portions are provided at intervals around the open end of the inner cylinder, and extend to the downstream side of the first flow path from the open end of the inner cylinder.

According to this aspect, the eddy current inducing function can be satisfactorily maintained by forming the annular passage by the inner cylinder. On the other hand, a plurality of guide portions are arranged around the open end of the inner cylinder, and each of them extends to the downstream side of the first flow path from the open end of the inner cylinder. Therefore, even if the fluid flowing into the connection point from the upstream side of the second flow path contains fibrous foreign matter and the foreign matter floats on the swirling flow, it gets entangled with the guide portion and becomes an inner cylinder. Invasion is suppressed and it becomes easy to lead to the downstream side of the first flow path.

Further, by incorporating the detection unit into the hot water supply system so that the first flow path is a drop-in hot water supply path and the second flow path is a reheating circulation circuit, it is possible to suppress the intrusion of foreign matter into the rotating body side. Even if the hot water that circulates during reheating contains fibrous foreign matter such as hair, it is guided to the downstream side while being entangled with the guide portion in the process of floating in the annular passage and discharged. Even if the foreign matter cannot be discharged during the additional cooking, it can be discharged by passing water at the next hot water filling. That is, by applying the detection unit of this aspect to the hot water supply system, it is possible to prevent or suppress the fibrous foreign matter from being guided to the rotating body side.

According to the present invention, it is possible to provide a detection unit that is not easily affected by foreign matter that has entered from the outside while maintaining good detection performance.

It is a figure which shows the schematic structure of the hot water supply system centering on a detection unit. It is a figure which shows the structure of the 1st body. FIG. 2 (B) is a cross-sectional view taken along the line CC of FIG. 2 (B). It is a figure which shows the 2nd body. It is a figure which shows the foreign matter discharge action by providing the guide part. It is a figure which shows the foreign matter discharge action by providing the guide part. It is a figure which shows typically the foreign matter discharge structure which concerns on the modification. It is a figure which shows typically the foreign matter discharge structure which concerns on the modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of the members may be expressed with reference to the illustrated state.

FIG. 1 is a diagram showing a schematic configuration of a hot water supply system centered on a detection unit.
The hot water supply system of the present embodiment includes a drop-in hot water supply channel for dropping hot water adjusted to an appropriate temperature into the bathtub 13, and a reheating circulation circuit for reheating the hot water stored in the bathtub 13. The hot water through the drop hot water supply channel is supplied to the bathtub 13 via the hot water supply pipe 32. The hot water supply pipe 32 branches into a connecting passage 80 and a circulation passage 82. Both the connecting passage 80 and the circulation passage 82 are connected to the bathtub 13. A detection unit 68 is provided at these branch points P. The detection unit 68 is a branch pipe with a flow sensor, as will be described in detail later.

The reheating circulation circuit is composed of a circulation passage 82 and a connection passage 80. A heat exchanger 70 and a pump 84 are arranged in the circulation passage 82. At the time of reheating, the pump 84 is driven. Further, the heat exchanger 70 functions as a heat source. As a result, heat is exchanged between the hot water sent out from the bathtub 13 and the heat exchanger 70.

When filling the bathtub 13 with hot water, the hot water at an appropriate temperature branches at the branch point P and is supplied to the bathtub 13 via the connecting passage 80 on one side and circulated on the other side as shown by the solid line arrow in the figure. It is supplied to the bathtub 13 via the passage 82. The pump 84 is stopped at the time of filling with hot water, and the heat exchanger 70 does not function as a heat source. The amount of hot water supplied during hot water filling is calculated based on the detection value of the detection unit 68. When the supply of hot water at a predetermined flow rate is completed, the hot water filling is stopped.

On the other hand, at the time of reheating, the hot water in the bathtub 13 is sent out toward the heat exchanger 70 as shown by the dotted line arrow in the figure, and circulates in the reheating circulation circuit. The cold hot water discharged from the bathtub 13 to the circulation passage 82 is heat-exchanged by the heat exchanger 70 to raise the temperature, and is returned to the bathtub 13 again through the connection passage 80. By this reheating, the hot water in the bathtub 13 is warmed to an appropriate temperature.

In the present embodiment, the integrated value of the flow rate of hot water detected by the detection unit 68 is calculated when the hot water is filled, and the hot water supply is stopped when the integrated value reaches the set amount of hot water. As a result, the hot water filling is completed. Further, when reheating is performed, the detection unit 68 detects the presence or absence of circulation of hot water in the reheating circulation circuit. That is, the detection unit 68 functions as a flow sensor for detecting the amount of hot water discharged during hot water filling, and also functions as a flow switch for detecting the presence or absence of circulation of hot water during reheating. When the detection unit 68 functions as the latter flow switch, it is possible to obtain a guideline for the reheating end time from the circulation duration thereof.

The detection unit 68 includes a branch pipe 90 and a sensor unit 92. The branch pipe 90 is a pipe joint having a T-shaped body 91, connects the introduction pipe portion 94, the introduction outlet pipe portion 96, and the outlet pipe portion 98, and opens in three directions. The introduction pipe portion 94 is provided with an introduction port for introducing hot water, the introduction pipe portion 96 is provided with an introduction / outlet port for introducing or deriving hot water, and the outlet pipe portion 98 is provided with an outlet port for leading out hot water. Has been done. The introduction pipe portion 94 and the outlet pipe portion 98 are coaxially connected to form a straight pipe portion 95, and the introduction pipe portion 96 is connected so as to be orthogonal to them. The introduction pipe portion 96 and the outlet pipe portion 98 form a bent pipe portion 97 that bends at a right angle at their connection position.

The introduction pipe portion 94 has a first opening end 106, the introduction pipe portion 96 has a second opening end 108, and the outlet pipe portion 98 has a third opening end 110. The first opening end 106 functions as an introduction port for introducing hot water, the second opening end 108 functions as an introduction / exit port for introducing or deriving hot water, and the third opening end 110 functions as an outlet port for deriving hot water. .. Each of these open ends is a connection port for connecting the branch pipe 90 to another pipe. Inside the body 91, there is a linear first flow path 105 that connects the first opening end 106 and the third opening end 110, and a branch flow path 107 that branches from the first flow path 105 and connects to the second opening end 108. And a second flow path 109 connecting the second opening end 108 and the third opening end 110 are formed. The first flow path 105 and the second flow path 109 are connected to each other at an intermediate portion (a branch point of the first flow path 105 to the branch flow path 107). The connection point 111 coincides with the branch point P described above.

The straight pipe portion 95 has a pipe expansion portion 141 whose diameter is expanded at the position of the connection point 111. That is, the inner and outer diameters of the body 91 are increased so that the flow path diameter at the position of the connection point 111 in the first flow path 105 is larger than the flow path diameter on the upstream side thereof.

The body 91 includes a T-shaped tubular first body 93 and a straight tubular second body 99. The first body 93 constitutes an introduction pipe portion 94, an introduction pipe portion 96, and a pipe expansion portion 141, and the second body 99 constitutes a lead-out pipe portion 98. The first body 93 also has a connecting portion 102 that is connected to the pipe expanding portion 141 and is coaxial with the straight pipe portion 95. The second body 99 is assembled to the connecting portion 102 so as to be coaxial with the straight pipe portion 95. The second body 99 is provided with an upstream half portion inside the connecting portion 102 (inside the first body 93) and a downstream half portion outside the first body 93. Details of the structure of the second body 99 and the mode of assembly to the connecting portion 102 will be described later.

An annular recess 119 is provided at a position of the outer peripheral surface of the second body 99 facing the inner peripheral surface of the connecting portion 102. An annular seal member 123 is fitted in the annular recess 119. That is, a seal member 123 is interposed between the outer peripheral surface of the second body 99 and the inner peripheral surface of the connecting portion 102 (first body 93). With this configuration, leakage of hot water through the clearance between the second body 99 and the first body 93 is prevented.

The first open end 106 is connected to the hot water supply pipe 32. The second opening end 108 is connected to the circulation passage 82. The third opening end 110 is connected to the connecting passage 80. In this way, the branch pipe 90 forms a connecting portion of the hot water supply pipe 32, the connecting passage 80, and the circulation passage 82.

At the time of hot water filling (during hot water supply), as shown by the solid line arrow in the figure, hot water introduced from the hot water supply pipe 32 via the first opening end 106 flows so as to branch at the connection point 111. That is, on the one hand, the hot water goes straight through the connection point 111 and is guided to the connection passage 80 through the third opening end 110, and on the other hand, the traveling direction is changed by 90 degrees at the connection point 111, and the second opening end 108 It is guided to the circulation passage 82 through. On the other hand, at the time of reheating, as shown by the dotted line arrow in the figure, the hot water introduced from the circulation passage 82 through the second opening end 108 changes the traveling direction by 90 degrees at the connection point 111, and the third opening end It is guided to the connecting passage 80 via 110.

The sensor unit 92 includes a rotary flow sensor that outputs a detection signal based on the rotation of the impeller (rotating body). The sensor unit 92 includes a sensor main body 112 and a detection unit 114. The sensor body 112 includes a bottomed cylindrical body 116, a rotating shaft 118 extending along the axis of the body 116, and an impeller 120 (functioning as a "rotating body") fixed to the rotating shaft 118. .. A rectifier 121 is fitted to the upstream end of the body 116.

The impeller 120 has four blades 122 extending radially around a rotation shaft 118. The blades 122 are flat blades, and are provided on the outer peripheral surface of the rotating shaft 118 at 90 degree intervals. In the present embodiment, these blades 122 are obtained by molding a resin material mixed with magnetic powder, and the adjacent blades 122 are configured to show different magnetic poles. That is, the N pole and the S pole are alternately magnetized on the adjacent flat blades. In the modified example, a permanent magnet or the like may be fixed to the surface or the inside of the blade 122.

The detection unit 114 is composed of a magnetic sensor, and a sensor element such as a reed switch or a Hall element that detects a change in a magnetic field can be used. The detection unit 114 only needs to be able to detect the rotational state of the impeller 120, and the type can be appropriately selected. Although the detection unit 114 is embedded in the pipe wall on the side of the impeller 120, it may be arranged on the outer surface of the pipe.

The rotating shaft 118 can be formed of, for example, a metal or a resin. The rotating shaft 118 is rotatably supported at two points by a first bearing 124 provided at the center of the bottom of the body 116 and a second bearing 126 provided at the center of the rectifier 121.

That is, the bottom of the body 116 is provided with a circular boss-shaped first bearing 124 that slightly protrudes inward. A plurality of communication holes 128 that communicate inside and outside are provided around the first bearing 124 at the bottom of the body 116. The first bearing 124 is supported by a plurality of stays (not shown) radially arranged at the end of the body 116. A communication hole 128 is formed between adjacent stays.

On the other hand, the rectifier 121 has a shaft portion at the center of the ring-shaped main body, and the second bearing 126 is configured by a fitting groove provided on a surface of the shaft portion facing the rotating shaft 118. The upstream end of the rotating shaft 118 is slidably inserted into the second bearing 126. On the other hand, the downstream end of the rotating shaft 118 is slidably inserted into the first bearing 124. The first bearing 124 and the second bearing 126 function as "bearing portions" and are both located upstream of the connection point 111 in the first flow path 105.

The rectifier 121 generates a vortex in the vicinity of the upstream side of the impeller 120 when hot water flows through the first flow path 105. That is, when the blade 122 of the impeller 120 is composed of flat blades parallel to the rotation shaft 118 as described above, the flow of hot water for rotating the blade 122 needs to be a spiral axial flow. Become. Therefore, the rectifier 121 is provided with a plurality of rectifying blades 132 for forming a vortex on the upstream side of the impeller 120. The rectifying blade 132 is formed in a screw shape twisted around the axis. In this embodiment, three straightening vanes 132 are arranged at equal intervals (only one is shown in FIG. 1).

The plurality of rectifying blades 132 are connected in an annular shape at the outer edge portion to form a rectifying ring. The hot water flowing from the hot water supply pipe 32 through the first opening end 106 passes through the rectifying blade 132 and becomes a vortex corresponding to the twist of the rectifying blade 132, and is guided to the impeller 120. As a result, the impeller 120 rotates at an axial flow velocity of the eddy current, that is, a rotational speed corresponding to the flow velocity of the hot water. Then, the flow rate of hot water flowing in from the first opening end 106 can be calculated by detecting the change in the magnetic field according to the rotation speed of the impeller 120 by the detection unit 114. A calculation unit (not shown) can calculate the amount of hot water poured into the bathtub 13 by integrating this flow rate. This calculation unit constitutes a part of the control unit of the hot water supply system, but may be configured separately from the control unit. For example, it may be arranged integrally with the detection unit 114 or adjacent to the detection unit 114.

Although not shown, a part of the cylindrical side surface of the body 116 is a flat portion (D-cut shape). Further, the inner wall of the first body 93 that receives the sensor main body 112 is also formed as a flat portion. When the sensor main body 112 is assembled in the first body 93, the flat portions thereof can be engaged with each other to accurately position the sensor main body 112 in the rotational direction around the axis. The axis of the rotating shaft 118 coincides with the axis of the first flow path 105. For the positioning (press-fitting amount) of the sensor main body 112 with respect to the first body 93 in the axial flow direction, the bottom portion (end portion on the first bearing 124 side) of the body 116 is placed on the step portion 134 formed on the inner wall surface of the first body 93. It can be done by making contact.

The detection unit 68 has an inner cylinder 136 extending in the axial direction along the first flow path 105 and forming a double pipe structure with the pipe expansion portion 141 at the position of the connection point 111. The inner cylinder 136 is provided integrally with the first body 93, and extends in a cylindrical shape from the upstream side of the connection point 111 toward the center of the connection point 111. In the second flow path 109, the upstream side flow path 142 located on the upstream side of the connection point 111 and the downstream side passage 144 located on the downstream side of the connection point 111 are orthogonal to each other at the connection point 111. The downstream passage 144 is also a downstream passage of the first flow path 105, and is provided coaxially with the inner cylinder 136. By arranging the inner cylinder 136 in this way, an annular passage 138 is formed between the inner peripheral surface of the tube expansion portion 141 and the outer peripheral surface of the inner cylinder 136.

A tapered portion 137 is provided on the outer peripheral surface of the inner cylinder 136 in a manner symmetrical with respect to the axis L1 of the first flow path 105 (that is, the axis L1 of the downstream passage 144 of the second flow path 109). .. The tapered portion 137 is provided so that its outer diameter increases from the open end of the inner cylinder 136 toward the base end side. That is, the inner cylinder 136 is set so that the wall thickness becomes larger toward the base end side. Due to this structure, the annular passage 138 of the present embodiment has a smaller cross-sectional area than the case where the tapered portion 137 is not provided.

FIG. 2 is a diagram showing the configuration of the first body 93. FIG. 2A is a side view of the first body 93, and corresponds to the arrow view in the direction A of FIG. 1 (state in which the second body 99 is excluded). FIG. 2B is a cross-sectional view taken along the line BB of FIG.

As shown in FIG. 2A, a plurality of guide portions 150 are provided so as to project toward the downstream side in the tapered portion 137 (see FIG. 1). The plurality of guide portions 150 each have a columnar shape and are arranged on a predetermined virtual circle c centered on the axis L1. In the present embodiment, three guide portions 150 are provided at intervals of 90 degrees about the axis L1 and extend in parallel with the axis L1. The connecting portion 102 is provided with a pair of flange portions 152 extending in the radial direction symmetrically with respect to the axis L1, and screw holes 113 are formed in each flange portion 152.

As shown in FIG. 2B, a vortex inducing structure for generating a vortex at a position upstream of the connection point 111 in the first flow path 105 on the upstream side of the connection point 111 in the second flow path 109. Is provided. This eddy current-inducing structure is realized by setting the axis L2 of the upstream side flow path 142 of the second flow path 109 at a twisted position with respect to the axis L1 of the first flow path 105. The opening 143 to the connection point 111 in the upstream side flow path 142 is provided at a position biased to one side with respect to the axis L1 and opens to the annular passage 138. The opening 143 functions as a "second opening".

In this way, by guiding the hot water toward the connection point 111 in the second flow path 109 to a position biased to one side with respect to the axis L1 of the first flow path 105, the connection point 111 in the first flow path 105 A vortex can be generated at the position. When hot water is introduced through the second opening end 108 during reheating (see the dotted line arrow in the figure), the hot water is guided to the annular passage 138 through the opening 143. As shown by the alternate long and short dash line in the figure, this hot water hits one half of the pipe wall surface at the back when viewed from the second opening end 108 side, swirls along the inner peripheral surface of the pipe expansion portion 141, and moves downstream. You will be guided. This swirling flow of hot water creates a vortex. Since there is a swirling flow path on the extension line (projected position) of the opening 143, the eddy current inducing function is efficiently exhibited.

On the other hand, the plurality of guide portions 150 are provided at positions deviating from the extension line of the opening 143. Specifically, as shown in the figure, guide portions 150a and 150b are arranged above and below the axis L1, and guide portions 150c are arranged at positions opposite to the axis L2 with respect to the axis L1. The guide portions 150a to 150c are arranged along the opening end 139 of the inner cylinder 136 (see FIG. 2A). The guide portion 150a is at the farthest position and the guide portion 150b is at the closest position when viewed from the opening 143 in the direction of the axis L2. The guide portion 150c is located at the position farthest from the axis L2. Since the guide portions 150a to 150c have the same structure, they are collectively referred to as "guide portion 150" when they are not particularly distinguished.

As shown in the drawing, where the cross section of the guide portion 150 projects outward in the radial direction with respect to the cross section of the inner cylinder 136, the protruding portion is made to deviate from the extension line of the opening 143. As a result, the guide portion 150 does not become a factor that hinders the change in the flow at the initial stage when the hot water flowing from the opening 143 into the annular passage 138 becomes a swirling flow.

FIG. 3 is a cross-sectional view taken along the line CC of FIG. 2 (B). FIG. 3 corresponds to a cross-sectional view taken along the line XX in FIG.
In the present embodiment, as shown in the figure, the opening 143 has an oval or rectangular shape and opens into the annular passage 138. A part of the inner cylinder 136 is located on the extension line of the opening 143, but by adopting the tapered shape (tapered portion 137), the generation of the swirling flow is not substantially hindered. In the present embodiment, the height h of the inner cylinder 136 is set to about 1/2 of the width t (the length in the axis L1 direction) of the opening 143, but the size of the annular passage 138 and the positional relationship with the opening 143. It is possible to appropriately set a value for effectively generating a swirling flow in consideration of the above.

The guide portion 150 extends downstream of the first flow path 105 from the open end 139 of the inner cylinder 136. In the present embodiment, the tip position of the guide portion 150 is made to coincide with the position of the downstream side opening edge of the opening portion 143 (the position of the downstream end edge in the axis L1 direction). In the modified example, the length of the guide portion 150 may be longer than this. Since a sufficiently large space is formed between the adjacent guide portions 150, the swirling flow of hot water can induce a vortex flow through this space as well.

The vortex flow generated at the position of the connection point 111 is centered on the axis L1, and induces a vortex on the upstream side of the connection point 111 in the first flow path 105. At that time, the annular passage 138 guides a part of the fluid flowing from the upstream side passage 142 through the opening 143 to the connection point 111 so as to swirl around the axis L1. This promotes the generation of a vortex at the connection point 111.

The vortex induced by the vortex-inducing structure described above can rotate the impeller 120, and the rotation is detected by the detection unit 114 (see FIG. 1). That is, the impeller 120 is rotated at a rotation speed corresponding to the flow velocity even by the hot water flowing through the second flow path 109. Then, by detecting the change in the magnetic field according to the rotation speed of the impeller 120 by the detection unit 114, the calculation unit (not shown) can calculate the flow rate of hot water flowing through the second flow path 109.

In the present embodiment, when the impeller 120 is rotated by the hot water flowing through the second flow path 109, the calculation unit only detects whether or not the hot water is flowing. That is, in this embodiment, the impeller 120 is basically used as a flow switch. In the modified example, the impeller 120 may be used as a flow sensor for calculating the flow rate of hot water.

FIG. 4 is a diagram showing the second body 99. 4 (A) is a cross-sectional view, and FIG. 4 (B) is a view taken along the arrow C in FIG. 4 (A). The cross section shown in FIG. 4 (A) corresponds to the cross section shown in FIG.

As shown in FIG. 4A, the second body 99 has a cylindrical shape. A reduced diameter portion 149 is provided on the inner peripheral surface of the second body 99 from the upstream side opening end 101 to the central portion. The reduced diameter portion 149 has a tapered shape that reduces the diameter toward the downstream side. On the inner peripheral surface of the reduced diameter portion 149, four protruding portions 147 protruding inward in the radial direction are provided. The protrusion 147 is a rib extending parallel to the axis L1 of the downstream passage 144. Each of the four protrusions 147 is arranged around the reduced diameter portion 149 at intervals of 90 degrees. The protruding portion 147 extends in the axial direction from the upstream side opening end 101 to the middle of the tapered surface in the reduced diameter portion 149.

As shown in FIG. 4B, a pair of flange portions 115 are provided on the outer peripheral surface of the second body 99. An insertion portion 117 for inserting a screw (described later) is provided at the end of the flange portion 115. In the present embodiment, two insertion portions 117 are provided at positions symmetrical with respect to the axis L1 of the second body 99.

Returning to FIG. 1, a mode of assembling the second body 99 to the first body 93 will be described.
When assembling the second body 99 to the first body 93, the second body 99 is assembled to the first body 93 so that the insertion portion 117 and the screw hole 113 are aligned, and the screw 15 is inserted and fastened. As a result, the flange portion 115 is sandwiched between the screw head of the screw 15 and the end surface 103 of the first body 93, and the second body 99 is fixed to the first body 93.

The above-mentioned protruding portion 147 can be said to be a portion that protrudes inward in the radial direction from the inner wall of the body 91 in the flow path (downstream side passage 144) on the downstream side of the connection point 111 in the first flow path 105. Further, the diameter-reduced portion 149 can be said to be a portion of the downstream passage 144 whose diameter is reduced in the direction toward the downstream side.

By the way, when connecting a water heater arranged outdoors and a bathtub with a pipe at the time of construction of a hot water supply system, foreign matter such as pebbles existing outdoors may enter the pipe. If these foreign substances enter the second flow path 109 together with the hot water that circulates during reheating, the foreign substances may be guided to the sensor unit 92 together with the vortex flow. As a result, foreign matter may damage the impeller 120 and the like.

Therefore, in the present embodiment, in order to avoid or at least suppress such a situation, the tube expanding portion 141 is provided in the first body 93. The pipe expansion portion 141 is provided at the position of the connection point 111 in the first flow path 105. The inner and outer diameters of the pipe expanding portion 141 are expanded so that the flow path diameter in the pipe expanding portion 141 is larger than the flow path diameter on the upstream side of the connection point 111 in the first flow path 105. Further, an annular passage 138 is formed between the inner peripheral surface of the pipe expansion portion 141 and the outer peripheral surface of the inner cylinder 136. As described in connection with FIG. 3, the fluid guided to the annular passage 138 becomes a vortex. With this configuration, even if a foreign substance is mixed in the second flow path 109, the foreign substance is pushed to the inner peripheral surface of the tube expanding portion 141 by the centrifugal force of the vortex flow.

In the present embodiment, by providing the tube expansion portion 141, the distance between the inner peripheral surface of the body 91 (first body 93) at the connection point 111 and the open end of the inner cylinder 136 is sufficiently increased. In other words, in order to sufficiently increase the inner diameter of the body 91 at the connection point 111, the body 91 is expanded at the connection point 111 in this embodiment. With this configuration, foreign matter is suppressed from flowing from the open end 139 of the inner cylinder 136 to the sensor portion 92 side. As a result, the detection unit 68 can prevent damage to the impeller 120 and the like.

On the other hand, by expanding (diameter) the first body 93, the swirling velocity component of the hot water becomes considerably larger than the axial flow velocity component, that is, the hot water flows from the connection point 111 to the downstream side of the first flow path 105. It can be difficult. Therefore, as shown in FIG. 3, a protruding portion 147 is provided on the inner peripheral surface (upstream end of the downstream passage 144) of the second body 99. The protrusion 147 has a function of converting a swirling speed component of hot water into an axial flow speed component. Thereby, the flow of hot water in the downstream passage 144 in the axial direction can be promoted. That is, the foreign matter that has entered from the second flow path 109 can be efficiently guided to the downstream side.

Next, the action and effect of this embodiment will be described.
5 and 6 are diagrams showing a foreign matter discharging action due to the provision of the guide portion 150. FIG. 5 shows the analysis result by CAE (Computer aided Engineering), and shows the flow of hot water introduced from the opening 143 of the second flow path 109 to the connection point 111. In the figure, the flow of hot water is shown by streamlines, and the flow velocity is shown by shading. The flow of hot water is displayed only in the portion existing on the downstream side of the opening end 139 of the inner cylinder 136.

According to this analysis result, the hot water flowing into the connection point 111 from the upstream side passage 142 swirls along the annular passage 138 and changes into a vortex flow. A vortex is formed in such a manner that the hot water that has flowed in first wraps around the inside of the hot water that follows. In other words, the hot water flowing from the opening 143 to the connection point 111 begins to turn while being pushed outward by the hot water flowing earlier. Therefore, even if fibrous foreign matter such as hair is mixed in the hot water flowing in from the opening 143, it will flow toward the outer side in the radial direction of the annular passage 138, and will flow from the opening 143 to the inside of the inner cylinder 136. It is unlikely to be directly derived. The hot water that forms this vortex is guided to the downstream passage 144 on the front side (not shown) in the figure.

FIG. 6 shows the results of an experiment conducted using a visualization device simulating the detection unit 68. In the same experiment, hot water containing hair (foreign matter) was introduced from the opening 143 to the connection point 111, and the behavior of the hair was verified. 6 (A) to 6 (H) show the progress of the experiment. The arrows in the figure point to the hair.

According to the results of this experiment, the hair that has invaded the connection point 111 from the opening 143 is guided to the annular passage 138 together with the hot water and flows so as to extend in an annular shape along the swirling flow (FIGS. 6A to 6B). ). The hair moves inward in the radial direction as the turning progresses, and the movement is restricted by the guide portion 150 (FIG. 6 (C)). The hair is guided to the downstream side while being entwined with the three guide portions 150, and is discharged together with hot water (FIGS. 6 (D) to (H)).

As described above, according to the present embodiment, by providing the vortex inducing structure, the flow of hot water toward the connection point 111 in the second flow path 109 is biased with respect to the axis L1 of the first flow path 105. Can be guided to the correct position. As a result, a vortex that swirls around the axis L1 can be generated at a position upstream of the connection point 111 in the connection point 111 and the first flow path 105. The impeller 120 can be rotated by this vortex flow, and the detection performance of the sensor unit 92 can be ensured.

Further, the first body 93 (body 91) has a pipe expansion portion 141 at the position of the connection point 111 in the first flow path 105. Therefore, even if the foreign matter invades the second flow path 109 and flows into the connection point 111 together with the hot water, the foreign matter is pushed toward the inner peripheral surface of the pipe expansion portion 141 by the vortex flow. As a result, it is possible to prevent foreign matter from being guided to the inside of the sensor body 112, and it is possible to prevent damage to the impeller 120 and the like due to foreign matter. Foreign matter with a relatively large mass, such as pebbles, has a large straightness, but it can be pushed outward because the centrifugal force increases as it rotates along the vortex. In the case of a relatively light and long foreign matter such as hair, as described above, the guide portion 150 can guide the foreign matter to the downstream side while entwining it.

On the other hand, if the diameter of the connection point 111 is increased in this way, the cross-sectional area of the circular passage 138 becomes larger than necessary and the swirling speed component of the hot water is insufficient, a sufficient eddy current cannot be obtained and the sensor. There is a possibility that the detection performance of the unit 92 may be deteriorated. In this respect, in the present embodiment, the inner cylinder 136 is provided with a tapered portion 137 so that the outer diameter of the inner cylinder 136 increases from the opening end to the base end side. With this structure, an increase in the cross-sectional area of the flow path of the annular passage 138 can be suppressed, and the flow velocity of the swirling flow in the annular passage 138 can be sufficiently maintained. As a result, the eddy current-inducing structure can be sufficiently functioned, and the detection performance of the sensor unit 92 can be ensured.

In the present embodiment, the downstream passage 144 is further provided with a protrusion 147. With this structure, the flow in the rotational direction of the swirling flow (vortex flow) generated in the annular passage 138 is changed to the flow in the axial direction. As a result, the foreign matter can be efficiently guided to the downstream side without staying in the pipe expansion portion 141.

(Modification example)
7 and 8 are diagrams schematically showing a foreign matter discharge structure according to a modified example. FIG. 7 (A) shows a first modified example, and FIG. 7 (B) shows a second modified example. In the first and second modifications, the number of guide portions is different from that of the above embodiment. FIG. 8 (A) shows a third modified example, and FIG. 8 (B) shows a fourth modified example. In the third and fourth modifications, the shape of the guide portion is different from that of the above embodiment. These modifications are particularly effective in discharging foreign substances that are light and long, such as hair.

As shown in FIG. 7A, in the first modification, of the three guide portions 150 of the above embodiment, the guide portion 150c located on the side opposite to the axis L2 with respect to the axis L1 is omitted. The hair that has entered the connection point 111 from the opening 143 swirls together with the hot water flowing through the annular passage 138, but may be pushed inward in the radial direction by the hot water that subsequently flows in from the opening 143. In this regard, in the first modification, the guide portion 150b has the effect of canceling the inward urging in front of the subsequent junction with the hot water (that is, in the vicinity of the opening 143), so that the sensor side is moved to the sensor side. Can suppress the invasion of hair. Although it is preferable to provide the guide portion 150c of the above embodiment, omitting the guide portion 150b does not have the effect of omitting the guide portion 150b.

As shown in FIG. 7B, in the second modification, four guide portions 150 (guide portions 150a, 150d to 150f) are provided. The guide portion 150d is provided on the same side as the axis L2 with respect to the axis L1, and the guide portions 150e and 150f are provided on the side opposite to the axis L2 with respect to the axis L1. The distance between the adjacent guide portions 150 is equalized. Although the guide portion 150d is off the extension line of the opening 143, it is arranged in the immediate vicinity of the extension line. With such a configuration, an action of canceling the inward urging by the guide portion 150d can be obtained immediately before the confluence portion with the subsequent hot water. Further, since the number of guide portions 150 is larger than that of the above embodiment, a better foreign matter discharging effect can be expected.

The arrangement and number of the guide portions 150 are not limited to the above-described embodiment, the first modification, and the second modification, and can be appropriately set. When the number of the guide portions 150 is increased, the foreign matter discharging effect is enhanced, but the space between the guide portions 150 is reduced, so that the eddy current inducing effect may be reduced. Therefore, it is preferable to set so that both the eddy current inducing effect and the foreign matter discharging effect can be appropriately obtained.

As shown in FIG. 8A, in the third modification, the guide portions 160a to 160c are provided in place of the guide portions 150a to 150c of the above embodiment. Hereinafter, when these are not particularly distinguished, they are collectively referred to as "guide unit 160". The guide portion 160 has an oval cross section (elliptical cross section). The guide portions 160a to 160c are arranged so that their major axis faces the tangential direction of the inner cylinder 136. By adopting such a shape, resistance to swirling flow can be reduced.

As shown in FIG. 8B, in the fourth modification, the guide portions 170a to 170c are provided in place of the guide portions 150a to 150c of the above embodiment. Hereinafter, when these are not particularly distinguished, they are collectively referred to as "guide unit 170". The guide portion 170 has a streamlined cross section. The "streamline shape" here includes a shape whose thickness decreases along the flow direction of the swirling flow, such as a wing shape and a teardrop shape. The guide portions 170a to 170c are arranged so that the longitudinal direction of the cross section thereof faces the tangential direction of the inner cylinder 136. By adopting such a shape, it is possible to effectively suppress the generation of Karman vortices on the downstream side of the guide portion 170 that receives the swirling flow. As a result, the flow of the swirling flow can be smoothed and the resistance to the swirling flow can be reduced.

In another modification, the guide portion having such an oval shape or a streamlined cross section is arranged so that the longitudinal direction of the cross section faces a direction different from the tangential direction of the inner cylinder 136. You may. The longitudinal direction of the cross section may be oriented in a direction (optimal direction) in which resistance to swirling flow can be further reduced.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea of the present invention. Nor.

In the above embodiment, a configuration in which a columnar (circular cross-section) guide portion is integrally molded with the inner cylinder is illustrated. In the modified example, the pin may be assembled to the inner cylinder as a guide portion. Alternatively, a plurality of guide portions having an arc-shaped cross section having the same curvature as the open end of the inner cylinder may be provided. When forming the double tube structure on the body, a guide portion may be formed by providing a plurality of concave notches at the tip of the inner tube portion and the remaining portion thereof. In that case, the end face of the recess due to the notch constitutes the open end of the inner cylinder.

In the above embodiment, as shown in FIG. 2, the configuration in which the opening 143 is provided on the axis L2 of the second flow path 109 (that is, on the axis of the introduction / exit pipe portion 96) is illustrated. In the modified example, the opening 143 may be provided at a position offset from the axis L2 of the second flow path 109. That is, the central axis of the opening 143 may be shifted parallel to the axis L2. Thereby, for example, the distance between the axis L1 and the axis L2 can be shortened, and the first body 93 can be compactly configured.

In the above embodiment, as shown in FIG. 2, a configuration in which a plurality of guide portions 150 are provided at positions deviating from the extension line of the opening 143 (second opening) is illustrated. In the modified example, a guide portion (also referred to as a “specific guide portion”) may be provided on the extension line of the second opening. Then, the specific guide portion may be configured to be smaller than other guide portions. Specifically, the height of the specific guide portion may be made smaller than the height of the other guide portion. Further, the cross section of the specific guide portion may be smaller than the cross section of the other guide portion. By making the specific guide portion smaller, it is possible to prevent the specific guide portion from obstructing the rotation of hot water. On the other hand, by providing the specific guide portion, the action of pushing the fibrous foreign matter such as hair to the outside is enhanced.

In the above embodiment, an example is shown in which the base end of the guide portion 150 is set to the open end 139 (near the tip) of the inner cylinder 136. In the modified example, the base end of the guide portion may be set to the base end of the inner cylinder or an intermediate position in the height direction. Even in that case, the plurality of guide portions are provided at intervals around the open end of the inner cylinder. The guide portion is extended to the downstream side of the first flow path from the open end of the inner cylinder.

Although not described in the above embodiment, the guide portion may be configured so that the cross section becomes smaller from the base end to the tip end. As a result, fibrous foreign matter such as hair can be easily guided to the downstream side.

In the above embodiment, an example in which the inner cylinder is integrally molded with the body is shown, but the inner cylinder may be integrally molded with the bearing portion of the sensor. Alternatively, an inner cylinder (cylinder component) separate from the body may be arranged between the body and the bearing portion.

In the above embodiment, the first body and the second body are assembled to form the body of the detection unit. This structure is a structure in which only the second body (outlet pipe portion) can be replaced and the first body can be shared when the diameter of the pipe or the like connected to the third opening end changes. In the modified example, a single body in which the lead-out tube portion is integrally molded with the body may be used as the body of the detection unit. In this case, the protruding portion (protruding portion 147) may be integrally molded on the downstream side of the connection point in the second flow path of the body, or the protruding portion may be inserted from the third opening end and press-fitted into the body. You may. In either case, the protrusion is provided on the downstream side of the opening end of the upstream passage of the second flow path at the connection point. The number of protrusions can be set as appropriate.

In the above embodiment, the open end of the inner cylinder 136 is located at the center of the connection point 111, but it may be located on the upstream side of the center of the connection point 111. Alternatively, it may be located on the downstream side of the connection point 111.

In the above embodiment, a flat blade is adopted as the impeller 120, but for example, a screw-shaped blade (also referred to as a “twisted blade”) may be used. As a result, the rectifier 121 of the sensor body 112 can be replaced with a simple bearing member, and the component cost can be reduced. Even in such a configuration, since the rotating shaft 118 is supported at two points, it becomes easy to maintain stable rotation of the impeller 120.

Although not described in the above embodiment, a check valve may be arranged on the upstream side of the sensor unit 92 (detection unit) in the detection unit.

In the above embodiment, an example in which the rotating body is configured as an impeller having four blades is shown, but the number of blades is not limited to four and can be appropriately set. Further, as the rotating body, a flat plate or a rectifying shape (shape like a rectifying blade) can be adopted.

In the above embodiment, an example in which the detection unit is provided in a three-pronged branch pipe having three open ends is shown, but it goes without saying that the detection unit may be provided in various pipes such as a branch pipe having four open ends. stomach. In the case of a branch pipe having four open ends, for example, a first flow path connecting the first open end and the second open end and a second flow path connecting the third open end and the fourth open end are connected. It may be formed so that both flow paths are connected at an intermediate portion between them. In that case, the upstream side flow path of the first flow path connected to the first opening end and the downstream side flow path of the second flow path connected to the fourth opening end are linearly connected via the connection point. You may. Then, an impeller (rotating body) may be provided on a common rotating shaft, and the impeller may be arranged in the upstream flow path of the first flow path.

In such a configuration, the fluid from the upstream side to the connection point in the second flow path is guided to a position biased to one side with respect to the axis of the upstream side flow path of the first flow path, thereby in the first flow path. A vortex inducing structure that generates a vortex swirling around the axis may be provided on the upstream side of the opening to the connection point. Then, a cylindrical inner cylinder may be extended from the upstream passage of the first flow path toward the connection point to form a double pipe structure with the body. Similar to the above embodiment, a plurality of guide portions may be provided on the inner cylinder to prevent hair or the like from entering the rotating body side.

In the above embodiment, the pipe joint is the body of the detection unit. The body of the detection unit is not limited to the piping shape. In the modified example, a flow path may be formed in the resin block to form the body of the detection unit. Further, the material of the body is not limited to resin, and may be made of other materials such as stainless steel.

In the above embodiment, the outer peripheral surface of the inner cylinder is a tapered surface. In the modified example, it may be a convex curved surface, a concave surface or other inclined surface. It is preferable to adopt a shape in which the outer diameter of the inner cylinder increases from the open end of the inner cylinder toward the base end side.

In the above embodiment, an embodiment in which the detection unit is used with the first flow path oriented sideways has been described. In the modified example, the detection unit may be arranged so that the first flow path is vertically oriented with the third opening end facing downward. In both the embodiment and the modified example, the effect of providing the protruding portion in the downstream flow path is exhibited, but in the modified example, foreign matter such as stones is caused by gravity at a position downstream from the connection point in the second flow path. It is easy to flow in the direction of derivation. The protrusions function more effectively with the detection unit in the embodiment.

In the above embodiment, a mode in which the second body is attached to the first body with screws has been described. The assembling mode of the first body and the second body is not limited to this, and various methods such as providing a locking arm portion on the first body and a locking protrusion portion on the second body to lock the two bodies to each other. The assembly mode can be applied.

In the above embodiment, pebbles and hair are assumed as foreign substances mixed in the detection unit, but a good discharge effect can be obtained for other foreign substances such as plastic pieces and dust.

The present invention is not limited to the above-described embodiments and modifications, and the components can be modified and embodied within a range that does not deviate from the gist. Various inventions may be formed by appropriately combining a plurality of components disclosed in the above embodiments and modifications. In addition, some components may be deleted from all the components shown in the above embodiments and modifications.

13 Bathtub, 32 Hot water supply pipe, 68 detection unit, 70 heat exchanger, 90 branch pipe, 91 body, 92 sensor part, 93 first body, 94 introduction pipe part, 95 straight pipe part, 96 introduction pipe part, 98 out-licensing Pipe, 99 2nd body, 101 upstream opening end, 105 1st flow path, 106 1st opening end, 108 2nd opening end, 109 2nd flow path, 110 3rd opening end, 111 connection point, 112 sensor Main body, 114 detector, 118 rotary shaft, 120 impeller, 124 1st bearing, 126 2nd bearing, 132 rectifying blade, 136 inner cylinder, 137 taper part, 138 annular passage, 139 opening end, 141 pipe expansion part, 142 upstream Side flow path, 143 opening, 144 downstream side passage, 147 protrusion, 150 guide part, 160 guide part, 170 guide part, L1 axis line, L2 axis line.

Claims (8)

A detection unit for detecting the flow state of a fluid.
A body provided with a linear first flow path and a second flow path connected in the middle of the first flow path inside.
A rotating body having a rotating shaft extending along the first flow path and rotating according to the flow of a fluid passing through the first flow path.
A bearing portion provided on the upstream side of the opening to the connection point with the second flow path in the first flow path and rotatably supporting the rotation shaft.
A detection unit for detecting the rotational state of the rotating body, and
By guiding the fluid from the upstream side in the second flow path to the connection point to a position biased to one side with respect to the axis of the first flow path, the fluid is moved to the upstream side of the connection point in the first flow path. A vortex-inducing structure that generates a vortex that swirls around its axis,
An inner cylinder extending in the axial direction along the first flow path toward the downstream side of the bearing portion and forming a double pipe structure with the body at the position of the connection point.
With
An annular passage between the inner peripheral surface of the body and the outer peripheral surface of the inner cylinder for swirling the fluid flowing into the connection point from the upstream side of the second flow path around the axis of the first flow path. Is formed,
A plurality of guide portions projecting from the inner cylinder toward the downstream side of the first flow path are provided.
The plurality of guide portions are provided at intervals around the open end of the inner cylinder, and extend to the downstream side of the first flow path from the open end of the inner cylinder. unit. The vortex-inducing structure is located at a position where the second opening, which is an opening to the connection point in the second flow path, is biased to one side with respect to the axis of the first flow path and opens in the annular passage. The detection unit according to claim 1, wherein the detection unit is realized by providing the detection unit. The detection unit according to claim 2, wherein the plurality of guide portions are provided at positions deviating from the extension line of the second opening. The detection unit according to any one of claims 1 to 3, wherein the plurality of guide units are arranged on a predetermined virtual circle centered on the axis of the first flow path. The detection unit according to any one of claims 1 to 4, wherein the guide portion has a pin shape or a columnar shape. The detection unit according to claim 5, wherein the guide portion has an elongated circular cross section or a streamlined cross section along the swirling direction of the fluid in the annular passage. The outer diameter of the inner cylinder increases from the open end of the inner cylinder toward the base end side.
The detection unit according to any one of claims 1 to 6, wherein the plurality of guide portions are arranged along an open end of the inner cylinder. The body has a tube expansion portion in which both the inner diameter and the outer diameter are larger than those on the upstream side of the connection point at the position of the connection point in the first flow path.
The detection unit according to any one of claims 1 to 7, wherein the double tube structure is formed in the tube expansion portion.

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