JPWO2006132343A1 - Ultrasonic flow measuring device and ultrasonic flow measuring method - Google Patents

Abstract

Ultrasonic flow measurement device equipped with an ultrasonic flowmeter that measures the flow velocity distribution and flow rate of the fluid in the pipe by irradiating the ultrasonic wave to the fluid in the pipe and receiving the ultrasonic echo reflected by the reflector in the fluid In this case, a sufficient amount of bubbles are generated in the pipe with simple equipment, and the bubbles are diffused in the pipe without requiring a fluid machine having a stirring action. A bubble supply means is provided on the upstream side of the ultrasonic flowmeter, and a solid material having a property of sublimating in the pipe is supplied from the bubble supply means, or a granular solid material is supplied at a pressure higher than the pressure in the pipe. Inject into the pipe together with gas.

Description

  The present invention relates to an ultrasonic flow measuring device and an ultrasonic flow measuring method for measuring a flow rate of a fluid together with a flow velocity distribution, and more particularly, an ultrasonic flow measuring method for measuring a flow rate of a large-diameter pipe such as a nuclear power plant, a thermal power plant, or a hydroelectric power plant. The present invention relates to a sonic flow measurement device and an ultrasonic flow measurement method.

Conventionally, as a flow meter for measuring the flow rate of fluid flowing in a pipe, as disclosed in Patent Document 1, ultrasonic waves are applied to a fluid to be measured and the flow rate of the fluid is measured using ultrasonic Doppler shift. There are a correlation type ultrasonic flow meter and a correlation type ultrasonic flow meter that measures the flow rate of a fluid by using a correlation method from a time change of an echo signal from a reflector as disclosed in Patent Document 2.
JP 2000-97742 A JP 2003-344131 A

  Conventional ultrasonic flowmeters receive ultrasonic echoes reflected by reflectors present in the fluid and measure the flow velocity distribution of the fluid, thereby measuring the flow rate. There must be a sufficient amount of reflector in the fluid.

When there is not enough reflector in the fluid to be measured, gas is directly injected using a pump as shown in Patent Document 3, and ultrasonic waves are used as shown in Patent Document 4. The reflector is supplied by generating cavitation.
JP-A-8-62007 JP-A-6-294670

  However, pipes with a diameter of several meters, such as circulating water pipes for cooling turbine condensers at nuclear power plants and thermal power plants, and hydraulic iron pipes at hydroelectric power plants, have a large flow rate (several tens of tons to several In order to supply a sufficient reflector, a large amount of air has to be injected, and there is a problem that the incidental facilities become large.

  In addition, in order to uniformly distribute the injected gas in the pipe, an elbow or valve having a stirring action is required between the injection unit and the measurement unit. There are facilities that are difficult to install the injection part.

  The present invention has been made in view of the above problems, and generates a sufficient amount of bubbles in the piping with simple equipment and diffuses the bubbles in the piping without requiring a fluid machine having a stirring action. For the purpose.

  As a result of intensive studies to solve the above problems, the present inventors have found that by injecting a material that sublimates under pressure and temperature in a pipe, bubbles can be effectively generated, and the present invention is achieved. I came to

  That is, the present invention is as follows.

A first invention includes an ultrasonic flowmeter that irradiates a fluid in a pipe with ultrasonic waves, receives an ultrasonic echo reflected by a reflector in the fluid, and measures a flow velocity distribution and a flow rate of the fluid in the pipe. An ultrasonic flow measuring device,
A bubble supply means is provided upstream of the ultrasonic flowmeter for supplying a solid material that has the property of sublimating in a pipe and functioning as the reflector to form bubbles.

  The second invention is characterized in that the bubble supplying means is a solid carbonic acid supplying means for supplying solid carbonic acid as the solid material.

A third invention is characterized in that the bubble supply means injects a granular solid material into a pipe together with a gas having a pressure higher than the pressure in the pipe.
Here, the granular form refers to those having a diameter of 1 μm to 30 μm.
The high pressure gas to be mixed is preferably the same substance as the solid material, but may be a different substance, an inert gas such as carbon dioxide, nitrogen, argon, helium gas, or a mixture thereof. Or oxygen and hydrogen can be widely used.

The fourth invention measures the flow velocity distribution and the flow rate of the fluid in the pipe by irradiating the fluid in the pipe with ultrasonic waves by the ultrasonic flowmeter and receiving the ultrasonic echo reflected by the reflector in the fluid. An ultrasonic flow measurement method,
From the bubble supply means provided on the upstream side of the ultrasonic flowmeter, a solid material having the property of sublimating in the pipe is supplied into the pipe, thereby generating bubbles in the fluid and reflecting the bubbles. It is used as a body.

  The fifth invention is characterized in that the solid material is solid carbonic acid.

A sixth invention provides a granular solid material from the bubble supply means,
It inject | pours in the said piping with the gas of the pressure higher than the pressure in the said piping.
Here, the granular form refers to those having a diameter of 1 μm to 30 μm.
The high-pressure gas is preferably the same substance as the solid material, but may be a different substance, and as described above, an inert gas such as nitrogen, oxygen, or hydrogen, or a mixture thereof can be used.

  According to the ultrasonic flow measuring device and the ultrasonic flow measuring method of the present invention, it is possible to generate a sufficient amount of air bubbles even in a large-diameter pipe without biasing, thereby enabling highly accurate flow measurement. It becomes.

The figure which shows the hydraulic iron pipe of the hydroelectric power station used as an example of the flow measurement object by the ultrasonic flow measuring device concerning this invention. BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows 1st embodiment of the ultrasonic flow measuring device which concerns on this invention. The block diagram which shows 2nd embodiment of the ultrasonic flow measuring device which concerns on this invention. The block diagram of the ultrasonic flowmeter which comprises an ultrasonic flow measuring device.

  Hereinafter, an ultrasonic flow measuring device according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a hydroelectric power plant, which is one of application targets of an ultrasonic flow rate measuring apparatus according to the present invention.

  The hydroelectric power plant 20 is configured by providing a water turbine 23 between a hydraulic iron pipe 24 that connects a water tank 21 and a water discharge garden 22. The water turbine 23 is mechanically connected to the generator 25. The generator 25 converts the kinetic energy of the water turbine rotated by the river water x1 into electric energy, and the electric power generated by the generator 25 is sent to a power transmission system (not shown).

  In such a hydroelectric power plant 20, the ultrasonic flowmeter 13 is provided at an arbitrary portion of the hydraulic iron pipe 24. In this embodiment, the hydraulic iron pipe 24 constitutes a pipe through which a fluid to be measured flows.

  Further, in the first embodiment of the present invention, the solid carbonic acid supply means 11 is inserted into the water tank 21 as the bubble supply means, and in the second embodiment, the granular solid carbonic acid injection means 12 is inserted as the pitot tube of the hydraulic iron pipe as the bubble supply means. It is installed on the flange 26 for use. FIG. 1 shows the solid carbonic acid supply means 11 used in the first embodiment and the granular solid carbonic acid injection means 12 used in the second embodiment for convenience. As shown in FIG. 2 and FIG. 3, only one of them is installed, and each is used in combination with the ultrasonic flow meter 13.

  FIG. 2 is a configuration diagram showing a first embodiment of the ultrasonic flow rate measuring apparatus according to the present invention.

  The ultrasonic flow rate measuring device 10 includes a solid carbonic acid supply unit 11 and an ultrasonic flow meter 13 which are bubble supply units. The solid carbonic acid supply means 11 includes a heat insulating chamber 11a for storing solid carbonic acid 11c as a solid material that sublimates in the pipe, and an insertion pipe 11b for introducing the solid carbonic acid into the water tank, and is installed in the water tank 21 of the hydroelectric power plant. Is done.

  The ultrasonic flowmeter 13 irradiates bubbles as a reflector generated by sublimation of solid carbonic acid supplied into the hydraulic iron tube 24 with ultrasonic pulses, and receives reflected ultrasonic echoes. It has the function of measuring the flow velocity distribution of river water x1 in the iron pipe 24 and instantaneously measuring the flow rate in a time-dependent manner.

  The solid carbonic acid supplied from the solid carbonic acid supply means 11 flows with the fluid while sublimating. Since solid carbon dioxide sublimates to carbon dioxide whose volume is about 1000 times, a sufficient amount of bubbles can be supplied by a small amount of solid carbon dioxide. The size of the solid carbonic acid supplied by the solid carbonic acid supply means 11 is preferably 40 mm to 120 mm. If it is smaller than 40 mm, all of them sublimate well before reaching the measurement site, and the bubbles are biased. Moreover, when larger than 120 mm, there exists a possibility of reaching a turbine with a solid.

  FIG. 3 is a configuration diagram showing a second embodiment of the ultrasonic flow rate measuring apparatus according to the present invention.

  The granular solid carbonic acid injecting means 12, which is a bubble generating means, introduces a liquefied carbon dioxide cylinder 12a, a nitrogen gas cylinder 12b which is a gas to be mixed, a mixing means 12c, and a mixture. Although comprised of the introducing means 12d, a commercially available product (such as “Powder Shot” manufactured by Taiyo Nippon Sanso) may be used.

  Here, when introducing a mixture of granular solid carbonic acid and gas into the pipe, a pressure higher than the water pressure of the fluid in the pipe is required, but the pressure is adjusted using a regulator 12e of nitrogen gas. Alternatively, a separate mixing unit may include the compressor 12f.

  For introduction of the granular solid carbonic acid and gas mixture, a pitot tube insertion flange 26 provided in the pipe can be used.

  The gas has a large density difference from the fluid, so it is difficult to uniformly distribute in the pipe. However, in the solid carbonic acid state, the density is close to the fluid, so that it diffuses quickly and sublimates there to generate bubbles. Thereby, it is possible to efficiently supply well-diffused bubbles.

  The diameter of the granular solid carbonic acid is preferably 1 μm to 30 μm. If it is smaller than 1 μm, it sublimates immediately and the bubbles are biased, and if it is larger than 30 μm, it is difficult to diffuse.

  FIG. 4 is a diagram for explaining the configuration of the ultrasonic flowmeter 13.

  In a state where the ultrasonic transducer 13a is installed to be inclined in the flow direction of the river water x1 by an angle α with respect to the cross-sectional direction of the upstream side hydraulic iron pipe 24, the desired frequency f0 is obtained from the ultrasonic transducer 13a driven by the transmitter 13b and the emitter 13c. When this ultrasonic pulse is irradiated, the ultrasonic pulse hits the bubbles uniformly distributed on the measurement line ML in the river water x1 and is reflected to return to the ultrasonic transducer 13a as an ultrasonic echo. Here, the ultrasonic transducer 13a serves as a transmitter and a receiver, but may be provided separately.

  Then, the echo signal received by the ultrasonic transducer 13a calculates the flow velocity distribution along the measurement line ML by the flow velocity distribution measuring circuit 13f via the amplifier 13d and the AD converter 13e.

  The flow velocity distribution signal of the river water x1 calculated by the flow velocity distribution measurement circuit 13f is sent to the computer 13g which is a flow rate calculation means, where the flow velocity distribution signal is integrated in the radial direction of the hydraulic iron pipe 24 and the flow rate of the river water x1 is obtained. Is determined in a time-dependent manner.

  The flow rate calculated by the computer 13g and the flow velocity distribution which is the input value and other measurement conditions are displayed by the display device 13h and stored in the storage device 13i.

  In the present embodiment, the configuration in the hydroelectric power plant has been described. However, the present invention is not limited to this, and can be similarly applied to piping of a nuclear power plant and a thermal power plant.

Claims (6)

An ultrasonic flow measuring device equipped with an ultrasonic flowmeter that irradiates the fluid in the pipe with ultrasonic waves, receives ultrasonic echoes reflected by the reflector in the fluid, and measures the flow velocity distribution and flow rate of the fluid in the pipe Because
An ultrasonic flow rate measuring apparatus comprising bubble supply means for supplying a solid material having a property of sublimating in a pipe and functioning as the reflector, upstream of the ultrasonic flow meter.   2. The ultrasonic flow rate measuring apparatus according to claim 1, wherein the bubble supplying means is a solid carbonic acid supplying means for supplying solid carbonic acid as the solid material. The bubble supply means includes
What made the solid material into granules,
The ultrasonic flow rate measuring device according to claim 1, wherein the ultrasonic flow rate measuring device is injected into the pipe together with a gas having a pressure higher than the pressure in the pipe. An ultrasonic flow measurement method that measures the flow velocity distribution and flow rate of the fluid in the pipe by irradiating the fluid in the pipe with ultrasonic waves using an ultrasonic flowmeter and receiving the ultrasonic echo reflected by the reflector in the fluid. There,
From the bubble supply means provided on the upstream side of the ultrasonic flowmeter, a solid material having the property of sublimating in the pipe is supplied into the pipe, thereby generating bubbles in the fluid, and An ultrasonic flow rate measuring method characterized by being used as a reflector.   The ultrasonic flow rate measuring method according to claim 4, wherein the solid material is solid carbonic acid. From the bubble supply means,
What made the solid material into granules,
The ultrasonic flow rate measuring method according to claim 4, wherein a gas having a pressure higher than the pressure in the pipe is injected into the pipe.

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