CN202048938U - Trench weir type flow meter - Google Patents

Abstract

The utility model provides a weir-drain type flowmeter, which comprises a measuring tank. A weir plate is fixed inside the measuring tank. The weir plate divides the tank body of the measuring tank into a first section and a second section. A scale is fixed on the side, a water outlet is opened on the weir plate, and a level gauge for checking the levelness of the bottom plate between the first side wall of the measuring tank and the second side wall of the measuring tank is fixed on the measuring tank. The flowmeter of the utility model is provided with a level gauge on the measurement tank, and the flowmeter can be leveled according to the level gauge when placed, so that the accuracy of the measured flow rate is higher and the error in the measurement of small flow rate is reduced.

Description

Weir and channel flowmeter

technical field

The utility model relates to an instrument for measuring fluid flow, in particular to a weir-channel flowmeter.

Background technique

In hydraulic engineering, it is necessary to accurately grasp the flow and velocity of fluid. In engineering sites where more open channels are used, such as farmland water conservancy or constructed wetlands, the application of pipe flowmeters is subject to many restrictions, and the use of weir-type structures to measure flow is an effective method.

The measurement principle of the weir-ditch structure is: install a weir plate of a specific shape in a straight channel, and let the water flow overflow through the weir plate and discharge. According to the principle of fluid mechanics, there is a corresponding conversion relationship between the overflow water depth and flow.

Although building weir-type structures in rivers and canals can measure fluid flow, the construction process requires a lot of manpower and material resources, and is easily restricted by the terrain. However, the weir-type flowmeter made according to the structure of the above-mentioned structures is often measured due to The measuring tank is placed at an inclination to reduce the measurement accuracy.

Utility model content

The purpose of the utility model is to provide a weir and channel type flowmeter which is convenient for adjusting the level of the measuring tank and has high measurement accuracy.

The weir-channel flowmeter of the utility model includes a measuring tank, and a weir plate is fixed in the measuring tank, and the weir plate divides the tank body of the measuring tank into a first section and a second section, and the first section A scale is fixed on the inner side of the side wall, and a water outlet is opened on the weir plate, and the measuring tank is fixed with a measuring tank for checking the gap between the first side wall of the measuring tank and the second side wall of the measuring tank. A spirit level for the levelness of the bottom plate.

In the weir-ditch flowmeter of the present utility model, a balance plate is arranged between the first side wall and the second side wall, the balance plate is parallel to the bottom plate of the measuring tank, and the balance plate is The level is fixed in the middle.

In the weir-drain type flowmeter of the present invention, the balance plate is located above the first section.

In the weir and channel flowmeter of the present invention, the level is a bubble level.

In the weir and channel flowmeter of the present utility model, the water outlet is an inverted isosceles triangle, the top angle of the water outlet is 90 degrees, and the vertical central axis of the water outlet is vertical to the vertical axis of the weir plate. The central axis coincides.

In the weir-drain type flowmeter of the present invention, the length f of the first section and the opening width b of the water outlet satisfy: f=2.5×b.

In the weir-ditch flowmeter of the present invention, the linear distance from the scale to the weir plate is k, and k and the opening depth d of the water outlet satisfy: k≥3×d.

In the weir-ditch flowmeter of the present invention, handles are respectively fixed on the outer surface of the first side wall and the outer surface of the second side wall.

The flowmeter of the utility model is provided with a level gauge on the measurement tank, and the flowmeter can be leveled according to the level gauge when placed, so that the accuracy of the measured flow rate is higher and the error in the measurement of small flow rate is reduced.

Description of drawings

Fig. 1 is the three-dimensional view of the structural representation of flowmeter of the present utility model;

Fig. 2 is the top view of the structural representation of the flow meter of the present utility model;

Fig. 3 is A-A sectional view of Fig. 2;

Detailed ways

As shown in Fig. 1, Fig. 2 and Fig. 3, the weir-drain type flowmeter of the present invention includes an open rectangular measuring tank 1 made of plexiglass. A weir plate 2 is fixed inside the measuring tank 1, and a water outlet 21 is opened on the weir plate 2. The measuring tank 1 includes a first side wall 11 , a second side wall 12 and a bottom plate 15 . The bottom plate 15 is located between the first side wall 11 and the second side wall 12 . A level gauge 5 for checking the levelness of the bottom plate between the first side wall 11 and the second side wall 12 of the measuring tank is fixed on the measuring tank 1 .

The weir plate 2 is respectively perpendicular to the three inner walls of the measuring tank 1 . The weir plate 2 is provided with an inverted isosceles triangle water outlet 21, and the top angle α of the water outlet 21 is 90 degrees. The vertical central axis of the water outlet 21 coincides with the vertical central axis of the weir plate 2 .

The measurement principle of the weir-channel flowmeter is: install a weir plate of a specific shape in a straight channel, and let the water flow overflow through the weir plate and discharge. According to the principle of fluid mechanics, there is a corresponding conversion relationship between the overflow water depth and flow. In other embodiments of the present utility model, the water outlet on the weir plate may also be rectangular or other shapes. This embodiment only takes an inverted isosceles triangle as an example.

The opening depth of the water outlet 21 (ie the distance from the upper edge of the weir plate 2 to the top corner of the water outlet 21 ) is d, and the opening width of the water outlet 21 is b.

The weir plate 2 divides the tank body of the measuring tank 1 into a first section 13 and a second section 14 . Wherein the first section 13 is used as an upstream section where the fluid flows in, and the second section 14 is used as a downstream section where the fluid is discharged.

In order to stabilize the fluid state and ensure measurement accuracy, in this example, the length f of the first section 13 and the opening width b of the water outlet 21 satisfy: f=2.5×b.

A scale 3 is fixed on the inner side of the side wall of the first section 13 by bolts or glue. The linear distance from scale 3 to weir plate 2 is k. In order to ensure measurement accuracy, k and the opening depth d of the water outlet 21 should satisfy: k≥3×d.

According to the knowledge of fluid mechanics, there is a linear relationship between the depth of fluid flowing through the scale and the value of fluid flow. In this embodiment, the scale of the scale 3 represents the flow rate, and the scale is a non-uniform scale calculated by Q=1400h ^5/2 (L/s). Wherein, Q is the fluid flow rate, h is the depth of the fluid passing through the weir, that is, the depth from the liquid surface to the top angle 22 of the water outlet 21 when the fluid inside the first section 13 falls to the inside of the second section 14 through the water outlet 21 .

In order to adjust the level of the measurement tank 1 conveniently during measurement, a rectangular balance plate 4 is provided between the first side wall 11 and the second side wall 12 . The balance board 4 is located above the first section 13 . Balance plate 4 is preferably made of non-deformable material, such as steel, plexiglass and the like. Both ends of the balance board 4 are respectively fixed to the tops of the first side wall 11 and the second side wall 12 by bolts or glue. The balance plate 4 is parallel to the bottom plate 15 of the measuring tank 1 . The middle part of the balance plate 4 is fixed with a level 5, and the level 5 adopts a bubble level. For the convenience of placing and carrying the flowmeter, handles 6 are respectively welded on the outer surfaces of the first side wall 11 and the second side wall 12 of the measuring tank 1 .

When the weir and channel type flowmeter of the present utility model is to be used to measure the flow of water, the weir and channel type flowmeter of the present utility model is put into the water according to the direction of water flow, so as to ensure that the water flow in the measuring tank 1 should start from the first section 13 internal fluid Flow through the water outlet 21 to the inside of the second segment 14 . Adjust the measurement tank 1 to be approximately horizontal, and when the water flow is stable and the water flow does not submerge the weir plate, read the flow rate of the water flow through the measurement tank 1 by observing the value on the scale 3 through the water flow.

The weir channel flowmeter of the utility model has the following advantages:

(1) Compared with the permanently fixed weir body, the flow meter of the present utility model is convenient to move and install.

(2) The flow meter of the utility model is provided with a reasonable length of straight channel (ie, the first section 13 ) in front of the weir plate, so that the fluid flow state is stable, thereby ensuring the measurement accuracy.

(3) The flowmeter of the utility model is provided with a scale that can directly indicate the flow at a reasonable distance behind the weir plate. According to the flow-water level relationship formula applicable to the utility model, the scale of the utility model directly converts the water level into the flow rate, which is convenient for the user to read the final result.

(4) The flow meter of the utility model is provided with a balance plate equipped with a level gauge on the measuring tank body, and the flow meter can be leveled according to the balance plate when the flow meter is placed, so that the accuracy of the measured flow rate is higher and the measurement time of small flow rate is reduced. error.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present utility model.

Claims (8)

1. weir canal formula flowmeter, comprise measuring flume, the measuring flume internal fixation has weir plate, described weir plate is divided into first section and second section with the cell body of described measuring flume, be fixed with scale on the medial surface of described first section sidewall, have water delivering orifice on the described weir plate, it is characterized in that, be fixed with spirit-leveling instrument on the described measuring flume in order to the floor level degree between second sidewall of the first side wall of checking described measuring flume and described measuring flume.

2. weir according to claim 1 canal formula flowmeter is characterized in that, is provided with balance plate between described the first side wall and described second sidewall, and described balance plate is parallel with the base plate of described measuring flume, and the middle part of described balance plate is fixed with described spirit-leveling instrument.

3. weir according to claim 2 canal formula flowmeter is characterized in that described balance plate is positioned at described first section top.

4. weir according to claim 1 canal formula flowmeter is characterized in that described spirit-leveling instrument is a spirit level.

5. weir according to claim 1 canal formula flowmeter is characterized in that, described water delivering orifice is for falling isosceles triangle, and the drift angle of described water delivering orifice is 90 degree, and the vertical axis of described water delivering orifice overlaps with the vertical axis of described weir plate.

6. weir according to claim 5 canal formula flowmeter is characterized in that, the A/F b of described first section length f and described water delivering orifice satisfies: f=2.5 * b.

7. weir according to claim 5 canal formula flowmeter is characterized in that described scale is k to the air line distance of described weir plate, and the opening depth d of k and described water delivering orifice satisfies: k 〉=3 * d.

8. weir according to claim 1 canal formula flowmeter is characterized in that, is fixed with handle respectively on the lateral surface of the lateral surface of described the first side wall and described second sidewall.

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