JP2018194519A - Flow rate measurement device and sensor unit - Google Patents

Abstract

To provide a flow rate measurement device and a sensor unit which are excellent in input-output characteristics of an ultrasonic wave while having a suitable liquid proof property, in flow rate measurement of liquid.SOLUTION: A sensor unit 60 includes: an ultrasonic sensor 61 including a matching layer 61b (vibration surface) which ultrasonically vibrates to transmit/receive an ultrasonic signal; a cap member 62 which is arranged in a manner to face the matching layer 61b, and which covers the matching layer 61b in a manner to isolate liquid flowing through a measurement flow channel 51c; and grease 63 which is applied on the matching layer 61b, so as to fill a gap with the cap member 62.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a flow rate measuring device and a sensor unit.

  In recent years, against the background of global warming and the like, a solar hot water supply system using natural energy, particularly solar energy is known (see, for example, Patent Document 1). In this solar hot water supply system, in the process of obtaining the amount of heat, the flow rate of the liquid is measured by a flow rate sensor.

  On the other hand, in a field such as a gas meter, a technique for measuring a gas flow rate by an ultrasonic sensor is known (for example, see Patent Documents 2 and 3). Since an ultrasonic sensor in a gas meter is intended for measurement of gas, it is difficult to divert it directly to liquid flow measurement.

  For example, Patent Document 4 discloses an ultrasonic sensor that is unlikely to deteriorate even when this gas component is liquefied when used in the presence of petroleum gas. In this ultrasonic sensor, the sensor element is housed in a case composed of a matching layer and a case body, and the sensor element transmits and receives an ultrasonic signal through the matching layer.

JP2013-213644A JP 2008-2879 A JP 2008-2872 A JP 2002-277307 A

  By the way, the ultrasonic sensor includes many conductive members such as internal parts of the sensor element and terminals positioned on the side opposite to the vibration surface of the sensor element. When measuring the flow rate of a liquid with an ultrasonic sensor, it is necessary to make the vibration surface face the liquid, but it is technically possible to bring only the vibration surface into contact with the liquid without exposing these conductive members to the liquid. difficult.

  Further, according to the technique disclosed in Patent Document 4, since the matching layer is provided, there is no problem even if the matching layer and the liquid come into contact with each other. However, the technique disclosed in Patent Document 4 assumes a liquidproof property to the extent that a gas component is liquefied, and does not assume an environment exposed to a liquid when measuring the flow rate of the liquid itself. Absent.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a flow rate measuring device and a sensor unit that are excellent in ultrasonic input / output characteristics while having an appropriate liquid-proof property in liquid flow rate measurement. That is.

  In order to solve such a problem, the first invention is a flow rate measuring device having a measurement unit in which a measurement channel through which a liquid flows is formed, and a sensor unit that measures the flow rate of the liquid flowing through the measurement channel I will provide a. In this case, the measurement unit has a sensor attachment part to which the sensor unit is assembled so as to face the measurement flow path. In addition, the sensor unit includes an ultrasonic sensor having a vibration surface that vibrates ultrasonically to transmit and receive an ultrasonic signal, and a vibration surface that is disposed opposite to the vibration surface and separates the liquid flowing through the measurement flow path. And a grease applied to the vibration surface and filled in a gap with the cap member.

  Here, in the first invention, the cap member is preferably assembled to the sensor mounting portion via an annular seal member.

  In the first invention, the ultrasonic sensor includes a cylindrical sensor body in which a main surface located at an end vibrates, and a matching layer disposed outside the main surface of the sensor main body, and a cap. The member preferably has a cup shape that covers the matching layer and the peripheral side portion of the sensor body.

  Further, the second invention is a sensor unit that is assembled so as to face the measurement channel with respect to the measurement unit in which the measurement channel through which the liquid flows is formed, and measures the flow rate of the liquid flowing through the measurement channel. provide. The sensor unit includes an ultrasonic sensor having a vibration surface that vibrates ultrasonically to transmit and receive an ultrasonic signal, and a vibration surface that is disposed opposite the vibration surface and separates the liquid flowing through the measurement flow path. It is preferable to include a covering cap member and grease applied to the vibration surface and filled in a gap between the cap member.

  According to the present invention, it is possible to provide a flow rate measuring apparatus and a sensor unit that have an appropriate liquidproof property and excellent ultrasonic input / output characteristics in liquid flow rate measurement.

Explanatory drawing which shows typically the structure of the solar hot water supply system containing the reduction calorie | heat amount calculation apparatus which concerns on this embodiment. Front view showing a flow rate measuring apparatus according to the present embodiment Explanatory drawing which shows typically the internal structure of the flow measuring device concerning this embodiment Side view showing a flow rate measuring apparatus according to the present embodiment Explanatory drawing which shows the structure of a cap member Front view showing a modification of the flow measuring device

  FIG. 1 is an explanatory view schematically showing a configuration of a solar hot water supply system 1 including a reduced heat amount calculation device 5 according to the present embodiment. The solar hot water supply system 1 includes a water pipe 12, a hot water pipe 13, a mixed water pipe 14, and a heated water pipe 15. Further, the solar hot water supply system 1 includes a solar water heater 2, a mixing valve 3, and a water heater 4.

  The water pipe 12 supplies water to each of household water appliances such as a kitchen, a washroom, a bath, and a toilet. The water pipe 12 supplies cold water to the solar water heater 2.

  The solar water heater 2 has a heat collector 21, a heat medium pipe 22, and a hot water tank 23. The heat collector 21 is installed on a roof of a sunny house or the like, and takes in solar heat and warms the heat medium. Moreover, the heat medium piping 22 connects the heat collector 21 and the hot water storage tank 23, and has a structure in which the heat medium flows inside. The heat medium circulates through the heat collector 21 and the hot water tank 23 via the heat medium pipe 22. In the hot water storage tank 23, cold water from the water pipe 12 is introduced, and the cold water is heated by a warmed heat medium flowing through the heat medium pipe 22 to store hot water as preheated hot water.

  The hot water pipe 13 is a pipe for supplying preheated hot water from the hot water tank 23 to the hot water heater 4 side. A mixing valve 3 is installed at the end of the hot water pipe 13, and preheated hot water from the hot water pipe 13 is supplied to the mixing valve 3 from a hot water inlet 31 of the mixing valve 3. Further, the water pipe 12 is branched at the connection point A, and cold water from the water pipe 12 can be supplied to the mixing valve 3 via the cold water inlet 32 of the mixing valve 3. The mixing valve 3 mixes preheated hot water and cold water that flow in as described later to obtain mixed water.

  The mixed water pipe 14 is a pipe that connects the mixed water outlet 33 of the mixing valve 3 and the hot water heater 4, and the mixed water is supplied from the mixing valve 3 to the hot water heater 4 through the mixed water pipe 14. In addition, the mixing valve 3 in this embodiment is a hot water mixing valve with an automatic temperature adjustment function that automatically adjusts the mixing ratio of hot water and cold water so that the temperature of the mixed water becomes a predetermined temperature. However, the configuration of the mixing valve 3 is not limited to this.

  The water heater 4 includes, for example, a gas burner and a heat exchanger, and generates heated water (that is, hot water) having a temperature determined by a user or the like. This water heater 4 is connected to a remote controller for a hot water heater provided in a house, and based on a control signal received from the remote controller for a hot water heater, for example, the power on, the power off, and the temperature of the generated hot water are set. Is done.

  The heated water pipe 15 is a pipe that connects the water heater 4 and a shower port on the hot water supply side. The heated water warmed by the water heater 4 is supplied to the user or the like through the heated water pipe 15.

  With the above configuration, the solar hot water supply system 1 uses the solar water heater 2 using solar heat as the cold water from the water pipe 12 as preheated hot water and supplies it to the water heater 4. Thereby, the fuel cost used in the hot water heater 4, the amount of carbon dioxide discharged, and the like can be reduced.

  Next, the reduced heat amount calculation device 5 will be described. The reduced heat amount calculation device 5 calculates the heat amount and the carbon dioxide amount reduced by the use of the solar water heater 2 and displays the accumulated amount, and includes an arithmetic display 5a. Note that the reduced heat amount calculation device 5 may have a function of calculating and integrating and displaying a gas charge and carbon dioxide emission amount in addition to the heat amount.

  The reduced heat amount calculation device 5 includes a first temperature sensor T1, a second temperature sensor T2, and a flow rate measurement device US in order for the calculation display 5a to perform various calculations.

  The first temperature sensor T1 is disposed in the water pipe 12, and detects the water temperature before being heated by the solar water heater 2, that is, the temperature of cold water. The second temperature sensor T2 is disposed in the hot water pipe 13 and detects the temperature of the preheated hot water in the pipe (that is, in the hot water pipe 13) from when heated by the solar water heater 2 until it is supplied to the hot water heater 4.

  The flow rate measuring device US is a device that measures the flow rate of the liquid. Specifically, the flow rate measuring device US is arranged in the hot water pipe 13 and detects the flow rate of the preheated hot water supplied from the solar water heater 2 to the water heater 4. The flow rate measuring device US is an ultrasonic type.

  Hereinafter, the flow rate measuring device US which is one of the features of the present embodiment will be described. Here, FIG. 2 is a front view showing the flow rate measuring device US according to the present embodiment. FIG. 3 is an explanatory diagram schematically showing the internal structure of the flow rate measuring device US according to the present embodiment. FIG. 4 is a side view showing the flow rate measuring device US (excluding the sensor unit 60) according to the present embodiment.

  The flow rate measurement device US includes a measurement unit 50 and a pair of sensor units 60.

  The measurement unit 50 includes a unit casing 51, a cylindrical member 53, and a reflecting member 55.

  The unit casing 51 is a casing in which a series of hollow portions from the inlet 51a to the outlet 51b are formed. The unit housing 51 is formed of a metal material such as brass, for example. The unit casing 51 has a longitudinal shape along the axial direction (liquid flow direction) of the hollow portion. The end of the unit housing 51 on the inlet 51a side is provided with a screw thread 52 formed in a spiral shape on the outer peripheral surface thereof, and the end of the unit housing 51 on the outlet 51b side is provided on the outer peripheral surface thereof. A screw thread 52 formed in a spiral shape is provided. Each end portion of the unit casing 51 functions as a joint for screw-connecting a pipe (in this embodiment, the hot water pipe 13) through which the liquid to be measured flows. In this embodiment, the upstream hot water pipe 13 is connected to the inlet 51a side, and the downstream hot water pipe 13 is connected to the outlet 51b side.

  A cylindrical member 53 that is a cylindrical body having a circular cross section is fitted into the hollow portion of the unit casing 51. The cylindrical member 53 is formed from a resin material. The cylindrical member 53 forms a measurement channel 51 c through which liquid flows inside the unit housing 51.

  The reflection member 55 is disposed at a position facing the position where the sensor unit 60 is disposed in the unit housing 51. The reflection member 55 is fitted into a rectangular opening 51d formed at the center of the unit casing 51, and a table-shaped part 55a formed in a table shape protrudes into the measurement channel 51c. The upper surface 55a1 of the trapezoidal portion 55a is finished flat, and functions as a reflecting surface that reflects the ultrasonic signal transmitted from one sensor unit 60 to the other sensor unit 60.

  In the unit casing 51, sensor attachment portions 54 for attaching the sensor unit 60 are formed at two locations corresponding to the pair of sensor units 60. In the present embodiment, in the sensor mounting portion 54, the ultrasonic signal transmitted from one sensor unit 60 is reflected by the reflecting member 55 (the upper surface 55a1 of the base portion 55a) and received by the other sensor unit 60. As shown in FIG.

  The sensor mounting portion 54 is provided with a concave groove portion 54a into which the sensor unit 60 is fitted, and a pair of screw holes 54b for screwing the sensor unit 60. A communication portion 51e that communicates with the measurement channel 51c is formed at the center of the concave groove portion 54a.

  The sensor unit 60 transmits and receives ultrasonic signals to measure the flow rate of the liquid flowing through the measurement channel 51c, and is provided on the upstream side and the downstream side of the measurement channel 51c, respectively. In the present embodiment, a reflection type structure is adopted in which an ultrasonic signal transmitted from one sensor unit 60 via a reflection surface is received by the other sensor unit 60.

  Each sensor unit 60 includes an ultrasonic sensor 61, a cap member 62, and grease 63.

  The ultrasonic sensor 61 transmits and receives an ultrasonic signal, and for example, a piezoelectric element is used. The ultrasonic sensor 61 includes a cylindrical sensor body 61a, and a main surface (end surface) 61a1 located at an end portion is ultrasonically vibrated. A matching layer 61b is disposed on the outer surface (front surface) of the main surface 61a1 of the sensor main body 61a, and the matching layer 61b ultrasonically vibrates according to the ultrasonic vibration of the main surface 61a1. In the present embodiment, the matching layer 61b functions as the vibration surface of the ultrasonic sensor 61, but may be configured without the matching layer 61b (that is, the main surface 61a1 itself becomes the vibration surface). May be).

  FIG. 5 is an explanatory view showing the configuration of the cap member 62. The cap member 62 is a member that is disposed in the sensor attachment portion 54 of the unit housing 51 and attaches the ultrasonic sensor 61 to the unit housing 51. The cap member 62 also has a function of protecting the ultrasonic sensor 61 from the liquid flowing through the measurement channel 51c.

  The cap member 62 has a cup shape and is formed from a metal member. Specifically, one main surface 62a1 that faces the groove 54a of the sensor mounting portion 54 is provided with a convex portion 62b that enters the inside of the communication portion 51e. On the other hand, the other main surface 62a2 is provided with a bottomed recess 62c formed in a multi-stage shape. The ultrasonic sensor 61 is accommodated in the concave portion 62c so that the bottom surface 62c1 of the concave portion 62c and the matching layer 61b of the ultrasonic sensor 61 face each other. In this case, the concave portion 62c covers the main surface 61a1 of the sensor main body 61a including the matching layer 61b and the peripheral side portion 61a2 of the sensor main body 61a.

  Further, grease 63 is applied to the matching layer 61 b of the ultrasonic sensor 61. Therefore, the grease 63 is filled between the matching layer 61b of the ultrasonic sensor 61 and the bottom surface 62c1 of the concave portion 62c in a state where the ultrasonic sensor 61 is housed in the concave portion 62c. The grease 63 eliminates a gap (air layer) between the matching layer 61b and the bottom surface 62c1 (cap member 62), and transmits the vibration of the matching layer 61b, which is a vibration surface, to the bottom surface 62c1 of the cap member 62. Is responsible. Thereby, the ultrasonic signal output from the ultrasonic sensor 61 passes through the cap member 62 and is output to the measurement channel 51c. That is, an ultrasonic signal is output from the convex portion 62 b of the cap member 62.

  A pair of flange portions 62d are provided around the cap member 62, and an insertion hole 62d1 is formed in each flange portion 62d. The insertion hole 62d1 is a hole for guiding a screw (not shown) to the screw hole 54b when the cap member 62 is screwed to the sensor mounting portion 54.

  The sensor unit 60 is assembled to the sensor mounting portion 54 of the measurement unit 50 via the cap member 62. Specifically, the sensor unit 60 is fitted into the sensor mounting portion 54 with the main surface 62a1 side of the cap member 62 and the sensor mounting portion 54 facing each other. At this time, an annular seal member 70 such as an O-ring is fitted on the convex portion 62 b on the main surface 62 a 1 side of the cap member 62. Therefore, the seal member 70 is disposed between the main surface 62a1 of the cap member 62 and the groove portion 54a of the sensor attachment portion 54. In the assembled state of both, the convex portion 62b of the cap member 62 enters the center side of the communicating portion 51e located at the center of the groove portion 54a.

  In the measurement unit 50 having such a configuration, an ultrasonic signal is transmitted from one ultrasonic sensor 61 when the flow rate is measured. In this case, when the ultrasonic sensor 61 operates, the sensor body 61a ultrasonically vibrates the matching layer 61b disposed on the main surface 61a1. The vibration of the matching layer 61b is transmitted to the end face of the convex portion 62b of the cap member 62 via the grease 63 filled between the matching layer 61b and the cap member 62, and the end face is ultrasonically vibrated. Thereby, an ultrasonic signal is output from one sensor unit 60 so as to cross the liquid flowing through the measurement channel 51c obliquely. This ultrasonic signal is reflected by the reflecting member 55 and received by the other sensor unit 60.

  As described above, the sensor unit 60 according to the present embodiment is disposed so as to face the vibration surface, the ultrasonic sensor 61 including the vibration surface that ultrasonically vibrates in order to transmit and receive the ultrasonic signal, and the measurement channel. A cap member 62 that covers the vibration surface so as to separate the liquid flowing through 51c, and a grease 63 that is applied to the vibration surface and is filled in a gap with the cap member 62 are provided.

  According to this configuration, even if the ultrasonic sensor 61 is in an environment where it is exposed to a liquid, the cap member 62 covers the vibration surface, thereby providing an appropriate sealing property. Further, since the grease 63 is filled in the gap between the vibration surface and the cap member 62, the air layer is eliminated. Thereby, since the ultrasonic signal is appropriately propagated and output from the end face of the convex portion 62b of the cap member 62, the structure having excellent ultrasonic input / output characteristics is obtained. As a result, it is possible to provide a flow rate measuring device US having an appropriate liquidproof property and excellent ultrasonic input / output characteristics even when measuring the flow rate of a liquid.

  In addition, according to the present embodiment, liquid flow measurement can be added as an application of the ultrasonic sensor 61 used for gas flow measurement. In addition, when measuring the flow rate of a liquid such as water where the attenuation of the ultrasonic wave is very small, the ultrasonic wave is attenuated by passing through the metal cap member 62. It becomes possible to make the wave height of the size. Thus, both the transmission wave and the reception wave can be processed with the same specifications as the gas flow measuring device.

  Moreover, according to this embodiment, since the sealing member 70 is provided, the cap member 62 and the measurement unit 50 are joined in a watertight manner. Thereby, the ultrasonic sensor 61 located on the back side of the cap member 62 can be appropriately protected. Further, when the cap member 62 is in direct contact with the measurement unit 50, the vibration of the cap member 62 that outputs an ultrasonic signal is transmitted to the measurement unit 50, and the input / output characteristics may be degraded. There is. However, according to this embodiment, since the seal member 70 is interposed, vibration can be absorbed by the seal member 70. Thereby, it can be set as the structure excellent in the input-output characteristic.

  According to the present embodiment, the cap member 62 has a cup shape that covers the matching layer 61b and the peripheral side portion 61a2 of the sensor main body 61a. According to this structure, since the range which may be exposed to the liquid can be covered with the cap member 62, it can be set as a structure with high liquid-proof property.

  In the above-described embodiment, a reflective structure in which an ultrasonic signal transmitted from one sensor unit 60 is reflected and received by the other sensor unit 60 is employed. However, the structure of the sensor unit 60 and the structure of the flow rate measuring device US shown in the present embodiment are such that the ultrasonic signal transmitted from one sensor unit 60 is opposed to the sensor unit 60 as shown in FIG. You may apply to the structure received by the other sensor unit 60 in this.

  As described above, in the present embodiment, the flow rate measuring device has been described on the premise of the solar hot water supply system, but the present invention is not limited to this embodiment, and it goes without saying that various modifications are possible within the scope of the present invention. Yes. For example, it can be widely applied not only to a solar hot water supply system but also to a flow rate measuring device that measures the flow rate of a liquid flowing through a flow path. Further, the sensor unit provided in the flow rate measuring device also functions as part of the present invention.

DESCRIPTION OF SYMBOLS 1 Solar water heating system 2 Solar water heater 3 Mixing valve 4 Water heater 5 Reduction | restoration calorie | heat amount calculation apparatus 13 Hot water pipe US Flow measurement apparatus 50 Measurement unit 51 Unit housing 53 Cylindrical member 54 Sensor attachment part 55 Reflective member 60 Sensor unit 61 Ultrasonic sensor 62 Cap member 63 Grease

Claims (4)

A measurement unit in which a measurement channel through which liquid flows is formed;
A sensor unit for measuring the flow rate of the liquid flowing through the measurement flow path,
The measurement unit is
Having a sensor mounting part to which the sensor unit is assembled so as to face the measurement flow path;
The sensor unit is
An ultrasonic sensor having a vibration surface that vibrates ultrasonically to transmit and receive ultrasonic signals;
A cap member disposed to face the vibration surface and covering the vibration surface so as to separate the liquid flowing through the measurement flow path;
Grease applied to the vibration surface and filled in a gap with the cap member;
A flow rate measuring device comprising:   The flow rate measuring device according to claim 1, wherein the cap member is assembled to the sensor mounting portion via an annular seal member. The ultrasonic sensor is
A cylindrical sensor body whose main surface located at the end vibrates,
A matching layer disposed outside the main surface of the sensor body,
The cap member is
The flow rate measuring device according to claim 1, further comprising a cup shape that covers the matching layer and a peripheral side portion of the sensor body. In the sensor unit for measuring the flow rate of the liquid flowing through the measurement flow path, the measurement flow path through which the liquid flows is assembled so as to face the measurement flow path with respect to the measurement unit formed inside.
An ultrasonic sensor having a vibration surface that vibrates ultrasonically to transmit and receive ultrasonic signals;
A cap member disposed to face the vibration surface and covering the vibration surface so as to separate the liquid flowing through the measurement flow path;
Grease applied to the vibration surface and filled in a gap with the cap member;
A sensor unit comprising:

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