SU987391A1 - Device for measuring water consumption in drainage systems - Google Patents

Description

The invention relates to hydrometry and can be used to measure the flow of water in drainage systems, in pressureless pipes, in hydraulic trays and open channels.

Known water-measuring device having an end weir and leveling device

Flow measurement with thin-wall spillways or conical nozzles in canals, and especially in closed drainage systems, is associated with the creation of a backwater, which, besides introducing inaccuracies in flow measurement, overstates the parameters of the channel, contributes to the siltation of the canals.

The closest to the proposed technical entity is a device for measuring the flow of water, sluggish supply and discharge pipelines, a measuring tray with a drain slit of variable cross section, a leveling device and a recording device 2j.

In the known device, measurement accuracy is also not ensured when measuring small flow rates due to the presence of pressure in front of the drain hole.

The aim of the invention is to improve the measurement accuracy by eliminating the flooding of the slot.

The goal is achieved by the fact that in the device for flow measurement in drainage systems containing inlet and outlet pipes, the measuring tray with

10 with a variable cross section slit, a level gauge and a registering device, a measuring tray and inlet nozzle are located with equal slopes, the drain slot is located in the bottom of the tray, the beginning of the slot is located in the cross section of the interface of the tray with the inlet pipe, in the direction of movement

20 flow of water.

In the device being described, instead of measuring the level before the weir, which is subject to the pressure of the flow of water, always formed

25 in front of it, the length of the jet of water flow in the slit of variable cross section is measured, which is the function of the flow rate.

Figure 1 shows a device for measuring the flow of water in drainage systems, a general view; in Fig.2 a horizontal longitudinal section aa in Fig.1.

The described device consists of an inlet pipe 1, which is fixed on the drainage opening 2. The inlet pipe is connected to the measuring tray 3 and is positioned relative to it by an equal inclination. The tray has a bottom drain slot 4, its beginning is located in the cross section of the junction of the tray with the inlet pipeline, while the cross section of the drain slot increases in the direction of movement of the water flow. A scale 5 is located on the bottom slit. The device contains a discharge pipe 6, a sensor 7 and a recording device 8,

The device works as follows.

Water from the drain hole 2 enters the measuring tray 3, for example, of a triangular shape and drains into the bottom slit 4, which has a variable cross-section along the length. The greater the flow of water, the farther from the beginning of the gap will be the flow curve decay. The flow rate can be observed visually on a scale of 5 or remotely using the well-known sensor 7, which can determine the length of the jet of water flow, and a recording device 8. Water after draining into the bottom slit 4 flows through the discharge pipe b, turning off the flooding of the measuring tray below.

The use of a device for measuring the flow rate of water in drainage systems, as shown by laboratory tests, will allow to achieve an unambiguous dependence of the flow rate on the propagation of the length of the drop curve of the jet stream in the gap, because in this device the flow rate and the gap area change linearly, and the remaining values entering in the composition of the flow equation, the constants.

3/2

2D L

About% - bo

where t is the coefficient of discharge;

B - slit width, variable c5

by lenght;

g is the gravitational constant; L is the propagation length of the decay curve of the jet stream bb-.

dy, counting from the beginning of the gap. The use of a measuring tray with a spillway bottom allows for a sufficiently high accuracy of measurement to allow free flow of water through the measuring tray, the passage of debris and sediment.

Due to the location of the measuring tray and supply pipe with an equal inclination relative to each other, the action of the measuring tray itself on the flow is eliminated, and this prevents backwater and improves the operating conditions of the drainage and irrigation systems.

Claims (2)

1. Kremlevsky P.P. Flow meters and quantity counters. L., Mechanical Engineering, 1975, p. 272-288. 2. Dub Ya.T., Shkurchenko V.L. Slotted flowmeters. K., Naukova, Dumka ,, 1972, p. 14 (prototype). ////////////// ///// 777 ///////// FIG. / Phage. 2