KR200425372Y1 - A flow measurements device for open channels utilizing the theory of inverted siphon - Google Patents

Abstract

In hydraulics, when a fluid flows in an enclosed space surrounded by a watertight solid wall, whatever its cross-section is, the fluid is lost to potential energy and flow head loss. It flows along the water inclination caused by the water inclination, which is called a pipe line, and the open channel has a free surface and flows by gravity. Flow. The free surface of the channel is under atmospheric pressure, and the irrigation channel receives hydraulic pressure from the head. Many sewage pipes seem to be similar to constant water pipes, but in reality, sewage in the pipes does not flow into a full pipe state, and only 80% of the diameter of the pipes causes the sewage to flow. These pipelines are classified by numbers because they allow them to secure free water.

Although these two types of flows are similar to each other in terms of passages through fluids, troubleshooting of channel flows is more difficult than that in irrigation canals. This is because the position of the free surface in the same channel changes with time and place, and the flow conditions in the channel are very complicated in terms of hydrology depending on the interdependence of depth, flow, channel bottom slope and free surface slope. . The irrigation canal is completely fixed and its flow cross section is determined. In most cases, it is a circular cross section, but the cross section of the canal varies from a circular shape to an irregular cross section of a natural river.

Although there are many types of flowmeters for irrigation canals using a wide variety of principles, there are only a few types of flowmeters because of the unique sulfur characteristics of the canals and the slight necessity. Typical flowmeters for canals are triangular or spherical Weirs and Parshall flume. When weir design and construction are very precise, the error range of the measured value is about ± 2%, and the accuracy of the foreign language is difficult to expect in the Parshall flume.

The interest in flow measurement was low for cash because of the relatively low prices of agricultural water, and because of the low demand for sewage flow, even if it was unnecessary or necessary. Even if there is a need to measure the flow rate of agricultural water or sewage as described above, the reality is that there is no suitable measuring equipment that can measure it easily and accurately.

The present invention forms an inverse siphon at a position where a flow rate measurement is necessary in the channel to solve the problems as described above, and always flows in the historically-funded conduit of the in-siphon which flows in a full pipe state. Ultrasonic flowmeters are installed in the unit to measure flow rates easily and accurately, contributing to rational and economical water management.

Inverted siphon, inverted siphon conduit, water elevation at the upstream side, upstream side, at the downstream side, at the downstream side, Weir ), Ultrasonic flowmeter, ultrasonic transducer, nito pit.

Description

A flow measurement device for open channels utilizing the theory of inverted siphon

Figure 1 is a general view for explaining the principle of the time difference type ultrasonic flowmeter according to the present invention.

Figure 2 is a history-funnel longitudinal view including a parallax type ultrasonic flowmeter according to the present invention.

Figure 3 is an inverse plan view including a parallax type ultrasonic flowmeter according to the present invention.

Figure 4 is a plan view attached to the outside of the parallax type ultrasonic flowmeter according to the present invention.

* Explanation of Signs of Major Parts of Drawings *

10 upstream pipe flange 11 upstream flange connection life preserver

12 pipe 13 upstream ultrasonic transducer (Transducer)

14: downstream ultrasonic transducer

15: Lifesaving for downstream flange connection bolt

16: downstream pipe flange

V: flow rate in the pipe, m / s

L: distance between a pair of ultrasonic transducers 13 and 14, m

θ: angle formed by the ultrasonic passage and the pipe axis

20: Upstream side channel 21: Upstream side Nito pit

22: upstream side nito pit lid 23: water level in the upstream side

24: historically funded conduit 25: downstream Nito pit lid

26: downstream Nito pit 27: downstream side channel

28: water level in the downstream side

H: Water level difference between the upstream and downstream channel (20, 27)

40: Upstream transducer fastening band

41: Band for tightening downstream transducer

The present invention contributes to the rational and economical water management by easily and accurately measuring the flow rate through the channel designed and constructed in the channel concept, such as agricultural or sewage pipelines.

Conventionally, since water is common and inexpensive, not only did not realize the necessity of water management for agricultural water or sewage, but also it was difficult to find a suitable measuring instrument to measure the flow rate of diarrhea. Typical flow measuring instruments are various kinds of weir and parshall flume.

Representative weirs include full weirs over the entire channel, spherical (Rectangular) weirs, Cippoleti weirs, and v-notch weirs. In order to measure the flow rate, the weir flow depth is measured, and this value is substituted into the experimental formula of each weir to obtain the flow rate. In the depth measurement of the overflow, in general, an ultrasonic water gauge is installed at the center of the channel, or a pressure sensor is put in the water to measure the water level by the head, and then, when the depth of the weir is obtained by subtracting the height of the weir base from the water level, various other methods may be employed. . The flow rate is calculated by applying the measured overflow depth and the experimental formula published for each of the above weirs. To obtain good results, weir structures must be constructed exactly as required by the design document. Only then can the measurement error range of the flow rate remain within ± 2%.

Parsall flume, on the other hand, is basically a flow measurement device using the principle of channel. Parsall flume consists of three parts: the converging section, the throat, and the diverging section. Parsall flume changes the type by shrinking the euro width, while at the same time falling to the water surface at the neck. Because the width of the neck is fixed, it is a free release. Parsall flume also measures the water level at a certain position and then the flow rate is calculated by substituting this value into the experimental formula. However, the construction of the device is difficult, but the operation is more difficult. In particular, the structure is relatively long, so a straight channel is required, and the measurement error range is generally larger than that of the weir.

As described above, the representative apparatuses for measuring the flow rate in the number have their own problems.

In order to solve the problems as described above, the present invention is to install an inverted siphon (Inverted siphon) at the position to measure the flow rate in the channel, and the time difference-type ultrasonic wave (Indifference-type) in the inducted conduit Install the flow meter. The parallax type ultrasonic flowmeter includes a display unit including a pair of ultrasonic transducers and a calculation unit. The present invention is a device that is formed by attaching a pair of ultrasonic transducers to an external predetermined location of the historic fund conduit, which requires almost no maintenance, and can record the flow rate by reading or transmitting the flow rate directly. It is aimed at maintaining reasonable and economical water management by maintaining ≤ 0.5%.

The present invention for achieving the above object relates to the measurement of the flow rate of the water channel built in the concept of a water channel, such as agricultural waterways or multiple sewage pipes, forming a history ephon (FIG. 2) at the position where the flow measurement is required, Immediately before the upstream side inlet section and immediately after the downstream side outlet section of the historically-funded conduit 24 of FIG. 2, the flow velocity is reduced to form an extended portion of the surface section for sedimenting the sediment flowing down with the flowing water. Nito pits 21 and 26 are formed at the bottom of the extended portion, respectively, and the depth of the nito pits 21 and 26 is 0.5m to 1.0m, and the downstream side of the upstream side nito pit 21 is formed. Horizontally forming an inferior ferrule conduit 24 between the wall and the upstream side wall of the downstream nito pit 26; The history-funded conduit 24 is formed in a straight line, the straight length of the conduit 24 is formed 15 times the diameter of the history-funded conduit 24; The pipe elevation of the historic loan conduit 24 is lower than the bottom elevation of the channel 27 in the downstream channel of the historical loan (FIG. 2); Fixing means for fixing a pair of ultrasonic transducers (13, 14) spaced apart from each other by a predetermined distance at a point 2/3 from the upstream end of the history-funch conduit (24) length; The fixing means is a number using the inverse siphon principle, characterized in that it comprises a fastening band to be installed using the upstream transducer fastening band 40 and the downstream transducer fastening band 41. Provided is a flow rate measuring device for a furnace.

Hereinafter, the flow rate measuring device of the channel (이용한 水 路) using the reverse siphon principle according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a general view for explaining the principle of the time difference (type) difference ultrasonic flowmeter according to the present invention, Figure 2 is a longitudinal-funnel longitudinal view including a parallax type ultrasonic flowmeter according to the present invention, Figure 3 Inverse plan view including a parallax type ultrasonic flowmeter according to Figure 4 is an external attachment of the parallax type ultrasonic flowmeter according to the present invention.

First, the basic measurement principle of the parallax type ultrasonic flowmeter will be briefly described as follows.

As the name implies, these devices measure the time it takes for ultrasonic energy to cross a pipe cross section and, based on this, measure the flow rate of fluid flowing in the pipe. The time taken to cross the pipe section is then measured for both the flow direction and the reverse direction of the fluid. In principle, the parallax type ultrasonic flowmeter is used in a state in which a fluid flows through a tube.

In FIG. 1, if the time (seconds) required for the ultrasonic energy to reach the downstream ultrasonic transducer 14 from the upstream ultrasonic transducer 13 is (T _13-14 ),

[Equation 1]

(T _13-14 ) = L / (C + Vcosθ).

Where C is the speed at which sound propagates in the fluid, m / s

L: distance between a pair of ultrasonic transducers (13, 14), m

V: V is the flow velocity of the fluid, m / s

θ: The angle formed by the ultrasonic path and the pipe axis. Degree

In FIG. 1, if the time (seconds) for the ultrasonic energy to reach the upstream ultrasonic transducer 13 from the downstream ultrasonic transducer 14 is (T _14-13 ),

[Equation 2]

(T _14-13 ) = L / (C-Vcosθ)

The above two equations can be summarized and expressed as follows.

[Equation 3]

Δt = (T _14-13 )-(T _13-14 )

= 2LVcosθ / (C ² -V ² cos ² θ)

In general, since the sound velocity C in the fluid at room temperature is 1000 m / s or more and the flow rate V is several m / s, C ² >> V ² cos ² θ is established.

[Equation 4]

Δt = 2LVcosθ / C ²

Thus, the flow rate V is written as

[Equation 5]

V = ΔtC ² / 2Lcosθ

By multiplying the flow rate (V, m / s) by the cross-sectional area (㎡) of the pipe for which the flow rate is to be measured, the flow rate (m 3 / s) can be obtained. Such a calculation is performed by an arithmetic unit built into the ultrasonic flowmeter. It can be sent to a display so that an administrator can read it directly or send it to display on a display or recorder at a location that is spaced apart. On the other hand, after installing the ultrasonic flowmeter at a predetermined position in any site, the data to be input when the flowmeter is initialized includes the material of the pipe, the diameter of the pipe, the thickness of the pipe, the angle θ formed by the ultrasonic path and the conduit axis, and the upstream ultrasonic transducer ( 13) the distance L between the downstream ultrasonic transducer 14, the viscosity of the fluid, the density of the fluid, and the temperature of the fluid.

Next, the history fund will be described with reference to FIGS. 2 and 3. To reduce sedimentation of nito due to earth and sand in the history-fund conduit 24, the flow rate is reduced just before the inflow and outflow part of the history-funded conduit 24 to settle the sediment flowing with the flow. Nitto pit (21, 26) is formed at the bottom of the extended means surface in order to expand the cross section and collect the sediment which is settled by the cross section expansion. Soil accumulated in the nito pits 21 and 26 over time opens the respective nito pit lids 22 and 25 and removes it intermittently through the openings formed. In order to settle the solids such as earth and sand, it is generally preferable to keep the flow rate at 0.6 m / s or less, so the surface of the means is appropriately expanded. The depth of the said nito pit (21, 26) is about 0.5m-1.0m.

The historically-funded conduit 24 forms a horizontally-funded conduit 24 horizontally through the downstream side wall of the upstream side nito pit 21 and the upstream side wall of the downstream side nito pit 26 so that the fluid flows well. Clean up both ends of. In order to reduce the head of the loss at both ends of the history-funded conduit 24, both ends are arranged in a bell mouth shape, and the flow rate in the history-funded conduit 24 is 0.8 m / s or more. Selected so that sediments such as nito are not wrapped in the bottom of the conduit 24. In addition, the pipe elevation of the historically-funded conduit 24 is made shallower than the bottom elevation of the historically-funded downstream channel (27), so that even when a flow amount of less than the normal flow rate flows through the upstream-side channel (20). The inside of the conduit 24 is always to be full water (滿 水). This is because the ultrasonic flowmeter shows the most accurate measurement when measured in a conduit flowing through a tube. The straight length (l) of the historically-funded conduit 24 is 15 times the diameter of the historically-funded conduit 24 for stable and accurate measurement of the fluid flow. The midpoint L / 2 of the distance L between the pair of ultrasonic flowmeter transducers 13 and 14 is two-thirds of the straight length l from the upstream end of the historically-funded conduit 24. Fasten the ultrasonic flowmeter transducers 13 and 14 to the position. The fastening means is fastened to a predetermined position on the outer wall of the history-funded conduit 24 by using the upstream transducer fastening band 40 and the downstream transducer fastening band 41.

The head of loss due to historical interest conduits (24) can be calculated by the following equation.

[Equation 5]

H = iℓ + 1.5 (v ² / 2g) + α

Where H is the head of loss of the historic fund (m)

i: Receipt slope for flow rate in historic Efund conduit (24)

ℓ: Historic Epon conduit (24) Length (m)

v: historic fund conduit (24) flow rate (m / s)

g: acceleration of gravity (9.8㎨)

α: clearance value (usually 3-5 cm)

Therefore, in consideration of the fact that the water level 28 of the down-stream of the historic channel is lower by Hcm than the water level 23 of the upstream side, the bottom elevation of the downstream channel of the historic-equip is determined.

Next, a method of fastening the parallax type ultrasonic flowmeter around the outer diameter of the inversely-funded conduit 24 will be described with reference to FIG. 4. There are various methods, but as shown in FIG. 4, two ultrasonic transducers 13 and 14 in a plane which are in contact with the central axis of the historically-funded conduit 24 are disposed on the outer diameter of the conduit with the historically-funded conduit 24 interposed therebetween. Fasteners are fastened at positions diagonal to each other by the converter fastening bands 40 and 41. In general, when the angle θ formed between the ultrasonic passage and the inversely-punched conduit 24 axis is about 30 degrees, the measurement performance of the ultrasonic flowmeter is better. The separation distance L between the upstream ultrasonic transducer 13 and the downstream ultrasonic transducer 14 is usually set to a distance when the angle θ becomes about 30 degrees.

The present invention may be variously modified and may take various forms, and the detailed description of the present invention has been described only with respect to specific embodiments thereof. It is to be understood, however, that the present invention is not to be limited to the specific forms referred to in the detailed description of the invention, but rather all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to include.

It was difficult to accurately measure the flow rate in various numbers, even cash, and it was not possible to perform economic and rational water management smoothly. When using the flow rate measuring device of the channel using the reverse siphon principle according to the present invention, Various problems such as the above is solved neatly will have a significant contributing effect to the public interests (明 若 觀 火).

Claims (1)

It relates to the measurement of the flow rate of waterways, such as agricultural waterways, sewage pipes, etc., where the historically-fund is formed at the position where flow measurement is required; Forming an extension portion of the surface of the sudan immediately before the upstream side and the downstream side outlet of the historically-funded conduit; A nito pit is formed at each of the bottoms of the guide means extended portion; The depth of the nito pit is 0.5m to 1.0m, respectively; Horizontally forming a history-funded conduit through the downstream wall of the upstream nito pit and the upstream wall of the downstream nito pit; Both ends of the history-fund conduit is formed in a bell mouth shape; The diameter is selected so that the flow rate in the history-funded conduit is 0.8 m / s or more; The pipe elevation of the historic fund is narrower than the floor elevation in the number of downstream historical funds; The straight length of the historic fund conduit is 15 times the diameter of the historic fund conduit; The pair of ultrasonic waves such that the midpoint (L / 2) of the distance (L) between the pair of ultrasonic flowmeter transducers is at a position that is two-thirds the straight length of the historically-funded conduit from the upstream end of the historically-funded conduit; Fastening flowmeter transducer; Means for fastening to the outer wall of the historic fund conduit using a fastening band; The fastening means is fastened to a position where the pair of ultrasonic transducers in a plane made in contact with the center of the historic-funch conduit are diagonal to each other on the outer diameter wall of the conduit with the historically-funded conduit interposed therebetween; And The separation distance between the pair of ultrasonic transducers is a distance in which the angle θ formed by the ultrasonic path and the inverse siphon conduit axis is about 30 degrees. Flow measuring device.

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