Parshall flume

1、 Product Overview

Basher trough (also known as Babbitt metering trough) is an auxiliary equipment used for measuring open channel flow. In the process of liquid flow, the waterway that flows in a non full pipe state is called an open channel. The application of open channel flow meters includes urban water supply channels, cooling water diversion and drainage channels for thermal power plants, sewage treatment inflow and discharge channels, industrial and mining enterprise wastewater discharge, as well as water conservancy engineering and agricultural irrigation channels.

2、 Measurement principle

The larger the flow in the open channel, the higher the liquid level; The smaller the flow rate, the lower the liquid level. For general channels, there is no definite correspondence between liquid level and flow rate. Because the same water depth and flow rate are also related to the cross-sectional area, slope, and roughness of the channel. Installing a measuring weir groove in the channel, the correspondence between the upstream water level and flow rate of the channel mainly depends on the geometric dimensions of the weir groove, as the gap of the weir or the contraction of the groove is smaller than the cross-sectional area of the channel. The same measuring weir tank is placed on different channels, and the same liquid level corresponds to the same flow rate. The measuring weir channel converts the flow into liquid level. By measuring the liquid level of the water flow in the measuring weir tank, and then reverse calculating the flow rate based on the corresponding water level flow relationship of the measuring weir tank.

3、 Installation precautions

1. The centerline of the Bacher trough should coincide with the centerline of the channel to prevent water flow from deviating into the Bacher trough.

2. After the Bacher trough is filled with water, the flow state of the water should be free flowing. The submergence degree of the Bacher trough should be less than the specified critical submergence degree.

3. The upstream of the Bacher Trough should have a straight section greater than 5 times the width of the channel to allow water flow to enter the Bacher Trough smoothly. There is no lateral deviation or the impact force formed by the slope of the channel.

4. The installation of the Bacher groove on the channel should be firm, tightly connected to the side walls and bottom of the channel, and not leak water; Make all the water flow through the Bacher trough, and the measuring point of the Bacher trough is the throat section inside the trough.

5. Before installation, first check the terrain. The inlet must be higher than the outlet to ensure a water level difference and smooth outflow There is a water level difference at the downstream discharge outlet of the Bacher trough, and the discharge is smooth. If the water level difference is not enough, the Bacher trough should be raised to increase the water level difference, and the discharge will be smooth without water accumulation.

4、 Installation diagram

Step 1: Place the Bacher trough into the open channel

The upstream of the Bacher trough should have a straight section greater than 10 times the trough width, keeping the trough horizontal. The centerline of the Bacher trough should coincide with the centerline of the channel to prevent water flow from deviating into the Bacher trough. The discharge outlet downstream of the Bacher trough is unobstructed; If it is not smooth, the Bacher groove should be raised to increase the water level difference.

Step 2: Strengthen the Bacher groove

Pour concrete around the Bacher groove to ensure that the groove does not deform; There should be support inside the large groove to ensure that it does not protrude. If the distance between the groove and the channel is too large, use bricks to build and maintain a distance of 50-100 millimeters between the groove and the bricks, and then fill and smooth it with cement mortar.

After the Basher trough is filled with water, it is ensured that all water flows through the Basher trough, and the flow state of the water should be free, without any lateral deviation or the impact force formed by the channel slope.

The water flow cannot submerge the Bacher trough, and the submergence degree must be less than the specified critical submergence degree; The measuring part of the Bacher trough is the throat section inside the trough.

5、 Several situations of installing Bacher groove

Attention: It is necessary to ensure that there is a water level difference downstream of the Bacher trough, the discharge is smooth, and there is no water accumulation.

1、 Basher groove construction dimensions

2、 Bacher trough water level flow formula