JP2017009343A - Flow rate detection device and water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate detection device capable of accurately detecting a flow rate and facilitate replacement work, and to provide a water supply device having the flow rate detection device.SOLUTION: A flow rate detection device 40 includes: a main shaft 42; a base 41 in which the main shaft 42 is fixed and detachably fixed to discharge piping 30 in such a posture that the main shaft 42 is horizontally in parallel in the piping; an impeller 43 supported by the main shaft 42; and magnetic detection part 45 detecting the rotation of the impeller 43.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an impeller-type flow rate detection device and a water supply device having an impeller-type flow rate detection device.

  In a building such as a building, a water supply device that supplies water to a water supply destination such as a faucet or a shower head is used. The water supply device drives the pump when the pressure detected by the pressure detection device provided on the secondary side of the pump becomes equal to or lower than the starting pressure while the pump is stopped. Thereafter, when the flow rate detection device detects that the flow rate is equal to or lower than the stop flow rate, the pump is stopped.

  An impeller-type flow rate detection device is known as a flow rate detection device. The impeller-type flow rate detection device includes a main shaft fixed in a vertical position in a pipe, an impeller that is rotatably supported around the main shaft, and that rotates by a passing water flow, and a detection that detects the rotation of the impeller Has a part. The flow rate detection device can detect the flow rate by extracting a signal proportional to the flow rate that has passed through the impeller.

  Depending on the axial length of the impeller, the flow velocity of the passing water varies depending on the portion of the impeller. For example, when the upper end of the impeller is located in the vicinity of the flow path wall surface and the lower end of the impeller is located on the center side of the cross section of the flow path, the flow velocity of the water flow passing through the lower end of the impeller and its vicinity is It becomes faster than the flow velocity of the water flow passing through the upper end and the vicinity thereof.

  For this reason, when the flow rate increases, the vicinity of the lower end of the impeller is pushed out to the secondary side by the water flow. When the vicinity of the lower end of the impeller is pushed out to the secondary side, the impeller is inclined with respect to the vertical direction.

  As the impeller tilts, the impeller receives a thrust force that pushes upward from the water. When this thrust exceeds a predetermined value, the impeller rises from the position supported by the support portion. The impeller then sinks when the thrust that pushes upward decreases with decreasing flow velocity.

  Since the flow speed when the impeller rises and the flow speed when the impeller sinks from the state where it rises differ, there is a hysteresis in which the rotational speed of the impeller differs when the flow rate increases and decreases. Arise. Due to the occurrence of hysteresis, it becomes difficult to accurately detect the flow rate value.

  On the other hand, for the purpose of improving measurement accuracy, a structure has been proposed in which the amount of protrusion that the impeller protrudes into the pipe is less than half the outer diameter of the impeller, and the main shaft is fixed in the pipe in a horizontal orientation. However, there is no description about the horizontal direction (for example, see Patent Document 1).

JP-A-11-101669

  As described above, the flow rate detection device that is fixed in the pipe in a posture in which the main shaft is parallel to the horizontal direction has the following problems. That is, since the main shaft is fixed to the pipe, for example, when the damaged main shaft is replaced, it is necessary to replace the entire pipe including the portion where the main shaft is fixed in the pipe, and the efficiency of the replacement work is deteriorated.

  An object of this invention is to provide the flow rate detection apparatus which can detect a flow rate correctly, and can perform replacement | exchange work easily, and the water supply apparatus which has this flow rate detection apparatus.

As one aspect of the present invention, a flow rate detection device includes a main shaft, a base that is fixed to the pipe in a posture in which the main shaft is fixed and the main shaft is parallel to the horizontal direction in the pipe, An impeller supported by the main shaft; and a detector that detects rotation of the impeller.
As one aspect of the present invention, the water supply device is configured such that a pipe through which water flows, a pump for increasing the pressure of the water, a main shaft, the main shaft are fixed, and the main shaft is parallel to the horizontal direction in the pipe. And a flow rate detection device including a base that is detachably fixed to the pipe, an impeller supported by the main shaft, and a detection unit that detects rotation of the impeller.

  The present invention can provide a flow rate detection device that can accurately detect a flow rate and that can easily perform replacement work, and a water supply device that includes this flow rate detection device.

Schematic which shows the water supply apparatus which concerns on one Embodiment of this invention. The top view which shows a part of discharge piping of the water supply apparatus. Sectional drawing which shows the 1st connection pipe of the discharge piping. Sectional drawing which shows the 1st connecting pipe.

  The water supply apparatus 1 which concerns on one Embodiment of this invention is demonstrated using FIGS. FIG. 1 is a schematic view showing a water supply apparatus 1. The water supply device 1 is, for example, a so-called directly-coupled pressure-increasing water supply device that is directly connected to a water main, boosts water supplied from the water main, and supplies water to a water supply destination such as a faucet or a shower head of a building.

  As shown in FIG. 1, the water supply device 1 includes a suction pipe 10, a plurality of pump devices 20 connected to the secondary side of the suction pipe 10, and a discharge pipe 30 connected to the secondary side of the pump 21 of the pump device 20. , A flow rate detection device 40 provided in the discharge pipe 30, a pressure detection device 60 provided in the discharge pipe 30, and a control device 70 configured to be able to control each of the pump devices 20.

  The suction pipe 10 has the same number of branch pipes 11 as the number of pump devices 20 connected to the suction pipe connected to the water main and the secondary side of the suction pipe.

  For example, two pump devices 20 are used. The pump device 20 includes a pump 21 connected to the secondary side of the branch pipe 11 and a motor 22 that drives the pump 21. The pump 21 is configured to increase the pressure of water from the branch pipe 11 so that the water can be pumped to the secondary side.

  FIG. 2 is a plan view showing a part of the discharge pipe 30. As shown in FIGS. 1 and 2, the discharge pipe 30 includes a first connecting pipe 31 connected to each secondary side of the pump 21, and a check valve connected to the secondary side of the first connecting pipe 31. 32, a junction pipe 33 connected to each secondary side of the check valve 32, and a water supply pipe 34 connected to the secondary side of the junction pipe 33.

  FIG. 3 is a cross-sectional view showing the first connecting pipe 31. As shown in FIG. 3, the first connecting pipe 31 is a bent pipe that bends 90 degrees. Specifically, the first connecting pipe 31 is connected to the discharge port of the pump 21 and extends upward, the bent pipe part 31b bent 90 degrees from the first pipe part 31a, and It has the 2nd pipe part 31c extended in the horizontal direction from the bending pipe part 31b.

  The first tube portion 31a has a shape that decreases in diameter toward the bent tube portion 31b. A rectifying plate 36 is provided in the first pipe portion 31a. The rectifying plate 36 has, for example, a cross shape in cross section, and divides the inside of the first tube portion 31a into four flow paths.

  The bent tube portion 31b is bent 90 degrees from the first tube portion 31a. For example, the flow path cross section orthogonal to the axis is formed to be substantially constant.

  FIG. 4 is a cross-sectional view of the second pipe portion 31c cut along a cross section orthogonal to the axial direction. As shown in FIGS. 2, 3, and 4, the second pipe portion 31 c has a housing portion 37 and an opening portion 38 that opens in the horizontal direction.

  The accommodating part 37 is continuously formed in the wall part of the bending pipe part 31b, for example. In other words, the accommodating part 37 is arrange | positioned in the secondary side immediately of the bending pipe part 31b. The accommodating part 37 has the surrounding wall part 37a and the end wall part 37b. The peripheral wall part 37a is provided in the upper part of the 2nd pipe part 31c, and protrudes upwards with respect to parts other than the peripheral wall part 37a. The peripheral wall portion 37a can be accommodated in the inner space by offsetting the axis of the impeller 43 of the flow rate detection device 40 in a posture parallel to the horizontal direction and above the flow path in the second pipe portion 31c. Is formed.

  The peripheral wall portion 37a has, for example, a semi-cylindrical shape. For example, the center of curvature of the inner surface of the peripheral wall portion 37a is disposed at a position offset upward from the flow path in the second pipe portion 31c.

  The end wall portion 37b is provided at one end of the peripheral wall portion 37a. The lower end of the end wall portion 37b protrudes into the second pipe portion 31c. As shown in FIG. 3, the end wall portion 37 b is formed in a circular shape having a larger diameter than the diameter of the impeller 43, for example, when viewed in the horizontal direction. The end wall portion 37b is formed with an accommodation hole 37c that can accommodate the tip end portion of the main shaft 42 of the flow rate detection device 40.

  The opening 38 is formed at a position that is coaxial with the accommodating portion 37 in the second pipe portion 31c, and is open in the horizontal direction. An internal thread is formed on the inner surface of the opening 38. The opening 38 is provided with a seal structure such as an O-ring.

  The check valve 32 is formed to be able to regulate the flow of water from the secondary side to the primary side.

  The merging pipes 33 are connected to the respective secondary sides of the check valves 32 and are formed so that water from the respective check valves 32 can be merged. The water supply pipe 34 is connected to the secondary side of the junction pipe 33, and the joined water is connected to a supply destination such as a faucet or a shower head.

  The flow rate detection device 40 is an impeller-type flow rate detection device that is configured to detect rotation of an impeller that rotates by receiving water and to output a signal corresponding to the rotation.

  The flow rate detection device 40 includes a base 41 that can be screwed into the opening 38, a main shaft 42 that is fixed to the base 41, a washer 46 provided on the main shaft 42, an impeller 43 that is rotatably supported by the main shaft 42, and an impeller. 43, a magnet 44 provided in 43, and a magnetic detector 45 for detecting the magnetic flux of the magnet 44.

  The base portion 41 includes a cylindrical portion 41a that can be screwed into the opening 38, a partition wall portion 41b that is formed in the cylindrical portion 41a, and a flange portion 41c that is formed at one end of the cylindrical portion 41a. Yes. The cylindrical portion 41 a is formed with a male screw that can be screwed into the female screw of the opening 38 on the peripheral surface thereof.

  The flange 41c and the opening 38 are liquid-tightly sealed by the above-described seal structure. The partition wall portion 41b is formed on the inner surface of the cylindrical portion 41a, and divides the inside of the cylindrical portion 41a in the axial direction. The base portion 41 is fixed to the opening portion 38, thereby closing the opening portion 38 in a liquid-tight manner. Further, by fixing the base 41 to the opening 38, the partition wall 41b divides the inside of the cylindrical portion 41a into two in the horizontal direction.

  The main shaft 42 is fixed to the partition wall portion 41b and extends parallel to the axial direction of the cylindrical portion 41a. Further, the main shaft 42 is disposed at a position where a range larger than 180 degrees around the main shaft 42 of the impeller 43 is covered by the peripheral wall portion 37a. Specifically, the main shaft 42 is disposed at a position where the axis is offset above the main flow path 100. The main flow path 100 is a portion where water mainly flows in the second pipe portion 31 c and is a portion excluding the space in the accommodating portion 37 and the space in the opening portion 38.

  For this reason, as shown in FIG. 3, the main shaft 42, when viewed in the horizontal direction, faces the inside of the second pipe portion 31 c, the primary edge E <b> 1 of the peripheral wall portion 37 a, the axis C of the main shaft 42, and The angle α formed by the secondary side edge E2 of the peripheral wall portion 37a is less than 180 degrees. The main shaft 42 is disposed in the vicinity of the outer periphery of the main channel 100 in the second pipe portion 31c. In other words, as shown in FIG. 3, the main shaft 42 is located slightly outside (upward) with respect to a straight line connecting the primary side edge E1 and the secondary side edge E2. The outer diameter of the distal end portion 42a has a diameter having a gap with the inner peripheral surface of the accommodation hole 37c.

  The washer 46 is fixed in the vicinity of the tip end portion 42 a of the main shaft 42 and protrudes in the circumferential direction from the peripheral surface of the main shaft 42.

  The impeller 43 includes a cylindrical shaft portion 43a, a plurality of blade portions 43b provided on the peripheral surface of the shaft portion 43a, and a bearing 43c provided in the shaft portion 43a. A through-hole having a larger diameter than the main shaft 42 is formed in the shaft portion 43a. The blade portion 43b has a size such that one side from the main shaft 42 passes through the center of the main channel 100 in the second pipe portion 31c or the vicinity of the center. For this reason, a portion on one side from the main shaft 42 of the blade portion 43 b receives water flowing in the center or near the center of the main channel 100.

  The bearing 43c is provided in the shaft portion 43a. The bearing 43c has the main shaft 42 disposed therein. The bearing 43c is rotatably supported by the main shaft 42. As the bearing 43c, for example, a cylindrical roller bearing is used. When the bearing 43c contacts the washer 46, the movement of the impeller 43 along the main shaft 42 is restricted. Note that the bearing 43c only needs to be rotatably supported by the main shaft 42, and may be, for example, a cylindrical member formed of a slippery metal.

  The magnet 44 is provided at the end of the shaft portion 43 a of the impeller 43 on the base 41 side. For example, the magnet 44 has a plurality of even poles magnetized in the circumferential direction.

  The magnetic detection unit 45 is, for example, a Hall IC. A part of the magnetic detection part 45 is provided in the partition wall part 41b. The remaining part of the magnetic detection unit 45 is provided on the opposite side of the impeller 43 with the partition wall 41b interposed therebetween. The magnetic detection unit 45 is configured to detect the magnetic flux of the magnet 44 and output a pulse signal.

  The flow rate detection device 40 configured in this manner is detachable from the second pipe portion 31c.

  The pressure detection device 60 is provided in the water supply pipe 34 and is configured to be able to detect the pressure on the secondary side of the pump 21.

  The control device 70 is configured to be able to receive the detection result of the flow rate detection device 40 and the detection result of the pressure detection device 60. The control device 70 is connected to the flow rate detection device 40 and the pressure detection device 60 by, for example, a signal line, and receives output signals from the flow rate detection device 40 and the pressure detection device 60 via the signal line.

  When the control device 70 determines that the pressure in the water supply pipe 34 is equal to or lower than the starting pressure based on the output result of the pressure detection device 60, the control device 70 controls the pump device 20 at a variable speed so that the discharge pressure of the water supply device becomes constant. Control. Further, when the control device 70 determines that the flow rate is equal to or lower than the stop flow rate based on the detection result of the flow rate detection device 40, the control device 70 stops the pump device 20.

Further, the control device 70 of the model that operates the two pumps performs disconnection control that shifts from the parallel operation to the single operation based on the detection result of the flow rate detection device 40.
In the case of a model that performs the estimated terminal pressure constant control, the target pressure is changed according to the increase or decrease of the flow rate based on the detection result of the flow rate detection device 40.

  In the flow rate detection device 40 configured as described above, the main shaft 42 is arranged in parallel to the horizontal direction, so that the impeller 43 is not affected even if the flow rate of water in the first connection pipe 31 increases as the flow rate increases. Does not move in the axial direction. For this reason, since the impeller 43 does not contact and leave from the part from the beginning, the dynamic frictional force accompanying the rotation does not change, and therefore the flow rate detection device 40 can accurately detect the flow rate.

  This effect will be specifically described. In the flow rate detection device in which the main shaft is parallel to the vertical direction, the impeller is supported by its own weight when its lower end contacts the main shaft or the like. The flow velocity at the center of the channel cross section is faster than the flow velocity on the channel wall surface. For this reason, when the lower end of the impeller is located near the center of the cross section of the flow path and the upper end of the impeller is located on the flow path wall side, the lower end portion of the impeller is pushed out to the secondary side depending on the flow velocity. Is inclined with respect to the vertical direction.

  When the impeller tilts, the impeller receives a thrust force that pushes upward from the flow of water. For this reason, when the impeller is lifted by the thrust, the dynamic friction force acting on the impeller 43 is reduced, so that the ratio of the rotational speed of the impeller to the flow rate is increased. Thereafter, when the impeller sinks from the state where the impeller has floated due to the decrease in the flow velocity, the lower end of the impeller contacts the portion supporting the lower end. Further, a hysteresis is generated in which the flow velocity when the impeller sinks is different from the flow velocity when the impeller ascends. This hysteresis makes it difficult to accurately detect the flow rate.

  However, in the flow rate detection device 40 of the present embodiment, the main shaft 42 is disposed in the pipe in a posture parallel to the horizontal direction, and the outer peripheral side of the blade portion 43b of the impeller 43 is the center of the cross section of the main flow path 100 or near the center. Since the root portion of the blade portion 43b is disposed on the outer peripheral side of the cross section of the main flow channel 100, the water flowing through the center or near the center of the cross section of the main flow channel 100 passes through the outer peripheral side of the impeller 43, Water flowing in the vicinity of the wall surface of the path 100 passes through the inner peripheral side of the impeller 43.

  For this reason, the impeller 43 changes in flow rate from the inner peripheral side (the shaft portion 43b side) to the outer peripheral side, but there is no change in the flow rate from one end to the other end in the axial direction, or there is no change in the flow rate. There are few. Specifically, on the outer peripheral side of the blade portion 43b, the flow rate of water passing through one end in the axial direction and the flow rate of water passing through the other end in the axial direction are the same or even if there is a difference. The difference is small.

  For this reason, since the axial direction edge part of the impeller 43 is not pushed out to a secondary side with respect to another part, the impeller 43 does not tilt as mentioned above. Since the impeller 43 does not tilt, no thrust is generated to move the impeller 43 in the axial direction to one side or the other side.

  For this reason, the flow rate detection device 40 according to the present embodiment does not have a hysteresis in which the relationship between the rotational speed of the impeller 43 and the flow rate follows different routes when the flow rate is increased and when the flow rate is decreased. It can be detected accurately.

  Further, the flow rate detection device 40 has a structure in which a base 41, a main shaft 42, and an impeller 43 are integrally formed and can be attached to and detached from the first connection pipe 31. For this reason, when a malfunction occurs in the flow rate detection device 40, only the flow rate detection device 40 needs to be replaced, so that the replacement work of the flow rate detection device 40 can be easily performed.

  As described above, the flow rate detection device 40 of the present embodiment can accurately detect the flow rate and can easily perform the replacement work.

  In the present embodiment, the flow rate detection device 40 is provided in an upper portion of the first connecting pipe 31 that is immediately on the secondary side of the bent pipe portion 31b. On the immediate secondary side of the bent pipe portion 31b, the flow rate of water flowing in the upper part of the flow path is faster than the flow rate of flowing in the lower part.

  For this reason, since the flow rate detection device 40 receives a flow of water with a high flow velocity, the ratio of the rotational speed of the impeller 43 to the flow rate can be increased even in a small water volume region. For this reason, the flow rate detection device 40 can stably detect the flow rate even in a small water volume region.

  Further, the distal end portion 42 a of the main shaft 42 is accommodated in an accommodation hole 37 c provided in the first connection pipe 31, and has a gap with the accommodation hole 37 c. For this reason, when the flow velocity of water passing through the impeller 43 becomes transiently excessive to generate an abnormal thrust, or when solid matter collides with the impeller and the main shaft 42 bends, the tip 42a of the main shaft 42 is bent. Contacts the inner surface of the receiving hole 37c. When the tip end portion 42a of the main shaft 42 comes into contact with the inner surface of the accommodation hole 37c, the main shaft 42 is restricted from further bending.

  Further, the impeller 43 is covered by the peripheral wall portion 37 a of the housing portion 37 in an angle range larger than 180 degrees around the axis of the main shaft 42. For this reason, a portion having an angle range smaller than 180 degrees around the axis of the main shaft 42 of the impeller 43 is disposed in the main flow path 100 and the other portion is disposed in the accommodating portion 37. In response to the flow of water flowing in the path 100, the water smoothly rotates in one direction.

  Further, the end wall portion 37 b of the accommodating portion 37 is a circular shape having a diameter larger than the outer diameter of the impeller 43, and faces the end portion of the impeller 43 in the axial direction of the impeller 43. In other words, as shown in FIG. 3, the impeller 43 is disposed on the inner side of the outer edge of the end wall portion 37b.

  For this reason, it is possible to prevent the impeller 43 from rotating from the axial direction by the end wall portion 37b, so that the impeller 43 can be stably rotated.

  Note that the present invention is not limited to this embodiment. The installation location of the flow rate detection device 40 is not limited. For example, the flow rate detection device 40 may be provided in a pipe extending in the vertical direction.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above.

  DESCRIPTION OF SYMBOLS 1 ... Water supply apparatus, 21 ... Pump, 40 ... Flow rate detection apparatus, 41 ... Base part, 43 ... Impeller, 45 ... Magnetic detection part (detection part), 30 ... Discharge piping (pipe), 31 ... 1st connection pipe ( (Connecting pipe), 31a ... first pipe part, 31b ... bent pipe part, 31c ... second pipe part, 37a ... peripheral wall part (wall part), 37c ... accommodating hole.

Claims (5)

The spindle,
A base that is fixed to the pipe so that the main shaft is fixed and the main shaft is parallel to the horizontal direction in the pipe;
An impeller supported by the main shaft;
A detection unit for detecting rotation of the impeller;
A flow rate detection device comprising: Piping through which water flows,
A pump for boosting the water;
A main shaft, a base portion to which the main shaft is fixed and the main shaft is detachably fixed to the pipe in a posture parallel to the horizontal direction in the pipe, an impeller supported by the main shaft, and the impeller A flow rate detection device comprising a detection unit for detecting the rotation of
A water supply apparatus comprising: The pipe includes a first pipe portion for flowing a vertical upward flow of water, a bent pipe portion bent by 90 degrees from a secondary side of the first pipe portion, and a horizontal line from a secondary side of the bent pipe portion. Comprising a tube having a second tube portion extending in a direction;
The water supply device according to claim 2, wherein the flow rate detection device is provided on an upper portion of the second pipe portion. The water supply device according to claim 2, wherein a housing hole for housing a tip portion of the main shaft is formed in the pipe. The water supply device according to claim 2, wherein the pipe includes a wall portion that covers the impeller around an angle range greater than 180 degrees and less than 360 degrees around the main shaft.