JPH0681378A - Ultrasonic flow velocity/flow rate measuring unit for water supply pipe - Google Patents

Abstract

PURPOSE:To fit a measuring unit with no suspension of water supply by slidably holding a rod-like body on an adapter removably fitted to the valve operation section of a fire hydrant branched from a water supply pipe, and pivotally fitting a movable rod having ultrasonic transceivers to the tip of the rod-like body. CONSTITUTION:The valve of the valve operation section 9 of a fire hydrant branched and erected from a water supply pipe 6, then an adapter 10 is fitted. When a rod-like body 12 and a movable rod 14 are thrust into the adapter 10 while the movable rod 14 is arranged in the axial direction of the rod-like body 12, one end of the movable rod 14 is brought into contact with the inner face of the water supply pipe 6 and rotated. When the rod-like body 12 is slightly lifted, the movable rod 14 is brought into contact with the upper wall of the water supply pipe 6 and is kept in parallel, and ultrasonic transceivers 15 at both ends of the movable rod 14 are arranged at an interval upstream and downstream along the upper wall of the water supply pipe 6.

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 supply 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, as shown in FIG. 6, one in which an insertion rod type electromagnetic flowmeter 2 is inserted into a water pipe 1 is seen. 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 flowmeter in waterworks that are piped underground, and this is not preferable for measuring the flow velocity and flow rate of the water in the waterworks.

From the above, the flow velocity using ultrasonic waves,
Means for measuring flow rate have come to be considered. That is, as shown in FIG. 7, an ultrasonic oscillator 4 and an ultrasonic receiver 5 are provided at two locations outside the water supply pipe 3. Then, the ultrasonic wave is radiated toward the inside of the tube, the arrival delay time of the ultrasonic wave is measured, and the sound velocity is integrated to calculate the inner diameter D of the tube. Further, 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 velocity by the sectional rod of the pipe.

[0004]

In order to accurately determine the flow rate with the above ultrasonic measuring means, it is necessary to accurately grasp the cross-sectional area of the pipe, that is, the inner diameter of the pipe. However, since the ultrasonic oscillator 4 and the ultrasonic receiver 5 are attached to the outer surface of the water supply pipe 3, the ultrasonic waves are reflected and attenuated on the inner and outer surfaces of the pipe, and in the case where the inner and outer surfaces have a paint layer, the above-mentioned attenuation occurs. However, it has not been realized as a measuring instrument because the delay time and sound velocity of the inside and outside of the pipe cannot be accurately grasped. Furthermore, in the water pipes buried in the ground, etc., there are few places where the outer surface of the pipes is exposed except for the water pipe bridges, etc., and it is difficult to attach an ultrasonic measuring instrument to the water pipe without civil engineering work. In consideration of the above-mentioned problems, the present invention provides an ultrasonic flow rate / flow rate measuring device such as a water supply pipe that can be installed without water cut even in a buried water pipe, and without civil engineering work, and can accurately measure the flow velocity and flow rate. The purpose is to provide.

[0005]

In order to achieve the above-mentioned object, an ultrasonic flow rate and flow rate measuring device such as a water supply pipe of the present invention comprises an adapter which is detachably attached to a valve operating portion of a fire hydrant branched from a water pipe. Consists of a slidable rod-shaped body that is held by an adapter, a movable rod that is pivotally connected to the tip of the rod-shaped body at its center, and ultrasonic oscillator receivers that are provided at both ends of the movable rod. To be done.

[0006]

In the ultrasonic flow velocity and flow rate measuring device having the above-described structure such as a water supply pipe, the valve of the valve operating portion of the fire hydrant branched from the water pipe is removed and the adapter is attached. The rod-shaped body held by the adapter is pushed into the water pipe through the fire hydrant, with the movable rod at the tip of the rod-shaped body being in the shape of a straight rod with the rod-shaped body. The movable rod that hits the inner wall of the tube rotates to be in a state along the tube wall, and the ultrasonic oscillation receivers at both ends are arranged in the tube with a space. 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 An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 6 is a water supply pipe, which is buried in the ground, and an underground fire hydrant 7 is branched and raised in part. The underground fire hydrant 7 has a branched upper portion, and has a digestion hose connection portion 8 on one side and a valve operation portion 9 on the other side.

The ultrasonic flow velocity / flow rate measuring device comprises an adapter 10 which is attachable to and detachable from the operating portion 9, a rod-shaped body 12 penetrating the adapter 10 and slidable in the axial direction, and a central portion at the tip of the rod-shaped body 12. Movable rod 14 which is pivotally attached by a pivot 13
And an ultrasonic oscillating receiver 15 provided at both ends of the movable rod 14, respectively. The ultrasonic oscillator receiver
A lead wire (not shown) to 15 is extended through the rod-shaped body 12 and the adapter 10 is provided with a seal member 11 that is in close contact with the rod-shaped body 12.

To mount the ultrasonic flow velocity and flow rate measuring device having the above-mentioned configuration on the water supply pipe 6, first, the valve operating portion 9 of the fire hydrant 7 is installed.
Remove the valve (not shown) and attach the adapter 10. Next, with the movable rod 14 aligned with the axial direction of the rod-shaped body 12, the movable rod 14 and the rod-shaped body 12 are pushed into the adapter 10. Due to this pushing, one end of the movable rod 14 has a water supply pipe 6
It hits the inner surface of and rotates as shown by the dotted line in FIG. The length of the movable rod 14 is slightly shorter than the inner diameter of the water supply pipe 6. Here, when the rod-shaped body 12 is slightly pulled up so as to be pulled out, the movable rod 14 has a position parallel to the upper wall of the water supply pipe 6, and two ultrasonic wave oscillation receivers 15 at both ends of the movable rod 14 are provided.
Are located along the upper wall of the water supply pipe 6 and at the required upstream and downstream sides.

The measurement is carried out by the ultrasonic flow velocity and flow rate measuring device mounted on the water supply pipe 6 as follows. Figure 4
As shown in FIG.
This is taken as a and b, and the connection between this and the amplifier 17 is switched to measure.

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

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

[Equation 1] On the other hand, the following equation is geometrically established.

[Equation 2] Here, the propagation of ultrasonic waves between the ultrasonic oscillation receivers a and b is only in water, and the sound velocity is only affected by temperature at pressures and water qualities such as water pipes. Therefore, temperature correction is appropriately performed. By doing so, accuracy can be secured even if the 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). Further, the average flow velocity V can be calculated by the following equation (7),
The flow rate Q can be calculated using a formula.

[Equation 4] The direction of the flow can be determined by the sign of equation (7).

As described above, the ultrasonic flow velocity and flow rate measuring device for the water supply pipe or the like of this embodiment can measure the inner diameter of the pipe and the average flow velocity of the front body, and can calculate the flow amount from the measured inner diameter and average flow velocity. Further, there are few factors that disturb the flow velocity distribution in the pipe, and since the average flow velocity in one cross section of the pipe is measured, there are few error factors in this aspect. Furthermore, since ultrasonic waves are directly radiated into the water, there is little return loss due to the tube wall, and it is possible to measure accurately with a small output.

[0013]

As is clear from the description of the above embodiment,
Since the ultrasonic flow velocity and flow rate measuring device such as the water supply pipe of the present invention is to install the main part in the pipe by using the fire hydrant branched and derived from the water pipe, even if the water pipe is buried in the ground, It can be installed without civil engineering work and without water interruption. Also, because the ultrasonic oscillation receiver is installed inside the tube, it directly radiates ultrasonic waves into the water, there is little return loss due to the tube wall, and it is possible to measure accurately with a small output. Since it is provided on the movable rod that is provided so as to rotate at the tip, the work of mounting it in the tube can be simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a state in which an ultrasonic flow velocity / flow rate measuring device according to an embodiment of the present invention is attached to a water supply pipe.

FIG. 2 is a front view of a rod-shaped body and a movable rod portion of the ultrasonic flow velocity / flow meter.

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 / flow meter.

FIG. 5 is an explanatory view of measurement by the ultrasonic flow velocity / flow rate measuring device.

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

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

[Explanation of symbols]

 6 Water supply pipe 7 Fire hydrant 9 Valve operating part 10 Adapter 12 Rod-shaped body 14 Movable rod 15 Ultrasonic oscillator receiver

Claims (1)

[Claims] 1. An adapter detachably attached to a valve operating portion of a fire hydrant that is branched from a water pipe, a slidable rod-shaped body held by the adapter, and a central portion slightly shorter than an inner diameter of the water pipe. An ultrasonic flow velocity and flow rate measuring device for a water supply pipe or the like, which comprises a movable rod rotatably pivotally connected to the tip of a rod-shaped body and ultrasonic oscillation receivers provided at both ends of the movable rod.