JP2803942B2 - Ultrasonic flow velocity flow meter for water pipes, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument for measuring the flow velocity and flow rate of a fluid such as a water pipe using ultrasonic waves.

[0002]

2. Description of the Related Art Generally, as a means for measuring the flow rate of a fluid in a water pipe, there is known a means for inserting an insertion rod type electromagnetic flow meter 2 into a water pipe 1 as shown in FIG. Although this measuring means can directly measure the flow rate, there are error factors such as disturbing the flow velocity distribution and changing the measurement accuracy depending on the insertion depth.
Further, it is difficult to insert an insertion rod type electromagnetic flow meter into a water supply pipe that is piped underground, which is not preferable for measuring the flow rate and flow rate of the water supply water.

[0003] From such a thing, the flow velocity using ultrasonic waves,
Means for measuring flow rates have become conceivable. That is, as shown in FIG. 7, an ultrasonic oscillator 4 and an ultrasonic receiver 5 are provided at two locations outside the water pipe 3. Then, the ultrasonic wave is emitted toward the inside of the tube, the arrival delay time of the ultrasonic wave is measured, and the sound velocity is integrated into the tube, so that the inside diameter D of the tube can be calculated. Also, when the ultrasonic wave is used, the flow velocity V in the tube is measured. The flow rate Q can be calculated by multiplying the flow rate by the cross section of the tube.

[0004]

In the above-described measuring means using ultrasonic waves, in order to obtain the flow rate with high accuracy, it is necessary to accurately grasp the cross-sectional area of the tube, that is, to accurately grasp the inner diameter of the tube. However, since the ultrasonic oscillator 4 and the ultrasonic receiver 5 are mounted on the outer surface of the water pipe 3, reflection and attenuation of ultrasonic waves occur on the inner and outer surfaces of the water pipe. It is not realized as a measuring instrument because the delay time and the speed of sound on the inner and outer surfaces of the pipe cannot be accurately grasped. Further, in water pipes buried underground or the like, there are few places where the outer surfaces of the pipes are exposed except for a water pipe bridge and the like, and it is difficult to attach an ultrasonic measuring instrument to the water pipe without civil engineering work. The present invention has been made in consideration of the above-mentioned problems, and has an ultrasonic flow rate flow rate measuring device such as a water pipe capable of being mounted without water interruption, even without burial, and without civil works, and capable of accurately measuring the flow rate. The purpose is to provide.

[0005]

In order to achieve the above object, an ultrasonic flow velocity measuring device such as a water pipe of the present invention is provided with an adapter detachable from a valve operating portion of a fire hydrant branched out from a water pipe, and an adapter. Consists of a slidable rod held by an adapter, a movable rod pivotally connected to the center of the rod at the center, and ultrasonic oscillation receivers provided at both ends of the movable rod. Is done.

[0006]

The ultrasonic flow rate measuring device such as the water pipe of the above-mentioned construction removes the valve of the valve operating part of the fire hydrant branched out from the water pipe and mounts the adapter. The rod held by the adapter is pushed into the water pipe through a fire hydrant with the movable rod at the tip of the rod being straight with the rod. The movable rod hitting the inner wall of the tube rotates and follows the wall of the tube, and the ultrasonic oscillation receivers at both ends are arranged in the tube at an interval. And the ultrasonic oscillation receiver emits ultrasonic waves into the tube, measures the tube diameter and flow velocity,
The flow rate is calculated based on this.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 6 denotes a water pipe, which is buried underground and partially branches an underground fire hydrant 7 to stand up. The underground fire hydrant 7 has a branched upper portion, one of which is a digestion hose connection portion 8 and the other is a valve operation portion 9.

The ultrasonic flow rate measuring device comprises an adapter 10 detachable from the operating section 9, a rod 12 penetrating through the adapter 10 and slidable in the axial direction, and a center at the tip of the rod 12. Part is pivotally mounted on a support shaft 13 and is rotatable
And the ultrasonic oscillation receivers 15 provided at both ends of the movable rod 14, respectively. The ultrasonic oscillation receiver
A lead wire (not shown) to 15 extends through the rod 12, and the adapter 10 is provided with a sealing member 11 that is in close contact with the rod 12.

First, the ultrasonic flow rate measuring device having the above configuration is attached to the water pipe 6 by first operating the valve operating section 9 of the fire hydrant 7.
The valve (not shown) is removed, and the adapter 10 is mounted. Next, the movable rod 14 and the rod 12 are pushed into the adapter 10 with the movable rod 14 aligned with the rod 12 in the axial direction. By this pushing, one end of the movable rod 14 is connected to the water pipe 6
And rotates as shown by the dotted line in FIG. Note that the length of the movable rod 14 is slightly shorter than the inner diameter of the water pipe 6. Here, when the rod 12 is slightly lifted so as to be pulled out, the movable rod 14 has a position parallel to the upper wall of the water pipe 6, and the two ultrasonic oscillation receivers 15 at both ends of the movable rod 14 are disposed.
Are located along the upper wall of the water pipe 6 and at a required interval upstream and downstream.

The measurement is carried out by the ultrasonic flow rate measuring device mounted on the water pipe 6 as follows. FIG.
As shown in FIG.
Are set as a and b, and the connection between this and the amplifier 17 is switched to measure.

The principle of the measurement will be described in more detail with reference to FIG. By switching the switch 16, the next state 1,
State 2 is set, and each oscillation frequency is measured.

[Table 1] This oscillation frequency is proportional to the time for the ultrasonic wave to propagate through the path length L, ignoring the delay time of the amplifier 17. When the states 1 and 2 are distinguished by suffixes (1) and (2), and their oscillation frequencies are obtained,

(Equation 1) On the other hand, the following equation holds geometrically.

(Equation 2) Here, the propagation of the ultrasonic wave between the ultrasonic oscillation receivers a and b is only in water, and the sound speed is affected only by the temperature at the pressure and the water quality of the water pipe, so that the temperature correction is appropriately performed. By doing so, the accuracy can be ensured even if an existing value is used. Therefore, if f ₁ and f ₂ are measured, L can be calculated from the following equation.

(Equation 3) On the other hand, since l is known, the inner diameter D can be calculated using the equation (5). The average flow velocity V can be calculated by the following equation (7), and
The flow rate Q can be calculated using the equation.

(Equation 4) Also, the flow direction can be determined from the sign of equation (7).

As described above, the ultrasonic flow rate measuring device such as the water pipe of the present embodiment can measure the inner diameter of the pipe and the average flow velocity of the front body, and can calculate the flow rate from the measured inner diameter and the average flow velocity. In addition, there are few factors that disturb the flow velocity distribution in the pipe, and the average flow velocity in one section of the pipe is measured. Furthermore, since ultrasonic waves are directly radiated into water, reflection attenuation due to the tube wall is small, and measurement can be performed with a small output and high accuracy.

[0013]

As is clear from the description of the above embodiment,
Since the ultrasonic flow rate measuring device such as a water pipe of the present invention uses a fire hydrant branched out from the water pipe to attach a main part to the pipe, even if the water pipe is buried underground, It can be installed without civil works and without water interruption. Also, since the ultrasonic oscillation receiver is installed in the tube, the ultrasonic wave is radiated directly into the water, the reflection attenuation by the tube wall is small, the measurement can be performed with high accuracy with a small output, and the ultrasonic oscillation receiver is a rod-shaped body Since it is provided on the movable rod provided to be pivoted at the distal end, the mounting work in the pipe can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an ultrasonic flow rate measuring device according to an embodiment of the present invention mounted on a water pipe.

FIG. 2 is a front view of a rod and a movable rod of the ultrasonic flow velocity measuring device.

FIG. 3 is a side view of the rod and the movable rod.

FIG. 4 is a circuit diagram of a switching connection portion of the ultrasonic flow velocity measuring device.

FIG. 5 is an explanatory diagram of measurement by the ultrasonic flow velocity flow meter.

FIG. 6 is a cross-sectional view showing a state of a conventional insertion rod type electromagnetic flow meter installed in a water pipe.

FIG. 7 is a cross-sectional view of a state of a conventional ultrasonic flow rate measuring device installed in a water pipe.

[Explanation of symbols]

 6 Water pipe 7 Fire hydrant 9 Valve operating section 10 Adapter 12 Rod 14 Movable rod 15 Ultrasonic oscillation receiver

Continuation of the front page (56) References JP-A-2-57908 (JP, A) JP-A-63-63835 (JP, A) JP-A-53-123171 (JP, A) JP-A-51-12159 (JP, A) , A) Japanese Utility Model 5-3368 (JP, U) Japanese Utility Model 60-455 (JP, U) Japanese Utility Model 61-1130 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB Name) G01F 1/66 E03B 7/07

Claims (1)

(57) [Claims] 1. An adapter detachably attached to a valve operating portion of a fire hydrant branched from a water pipe, a slidable rod held by the adapter, and a center part slightly shorter than the inner diameter of the water pipe. An ultrasonic flow rate measuring device such as a water pipe comprising a movable rod rotatably connected to a tip end of a rod-like body and ultrasonic oscillation receivers respectively provided at both ends of the movable rod.