The stainless steel Bacher groove was named by the American Civil Society in 1929. Afterwards, many countries such as the United Kingdom, Switzerland, Italy, India, Argentina, etc. also proposed various types of design schemes for Venturi tanks and conducted experiments, but the Bachel tank is still a popular tank in Venturi tanks.

Overall, the Bacher trough has a complex shape and is more expensive than weirs. In order to improve accuracy, it is necessary to measure the dimensions of each part of the trough accurately, which is its disadvantage. But there are also some advantages that other measuring devices cannot compare with: small water level loss (about one fourth of the weir), almost no sedimentation of solid substances in the water, small influence on flow velocity, and relatively small impact on the water level on the downstream side. Therefore, it is used to measure the flow rate of other liquids such as agricultural water and industrial water.

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 intake and drainage channels for thermal power plants, sewage treatment inflow and discharge channels, industrial and mining wastewater discharge channels, as well as water conservancy engineering and agricultural irrigation channels. Our company produces various specifications of measuring weir slots (Bacher slots) and weir plates (triangular weirs, rectangular weirs) that are used in conjunction with open channel flow meters.

　　purpose

Used in conjunction with an open channel flowmeter to convert the flow rate in the open channel into the level of the liquid. Measure the flow rate of water in an open channel. The flow rate of irrigation channels, sewage ditches, and urban sewers.

　　material

Glass fiber unsaturated polyester composite material (fiberglass reinforced plastic).

　　measurement range

Flow range: 10 liters/second to 10 cubic meters/second (determined by the specifications of the Bacher tank used)

The Bacher measuring tank consists of three parts: an upstream contraction section, a short straight throat, and a downstream diffusion section. The groove bottom of the contraction section tilts downstream, while the inclination direction of the diffusion section groove bottom is opposite to that of the throat groove bottom. Its structure is shown in the following figure.

Other constant terms need to be experimentally determined, generally as follows:, F=60cm, G=90cm; K=8cm, N--23cm,x=5cm, y=8cm; Depending on the depth of the channel, the height above the upstream water level is 0.1-0.2cm, and generally 1.00 meters can be used. The length of the bottom protection upstream and downstream of the measuring tank is a function of the height H of the tank bottom:

Upstream bottom protection L, two 4H;

Downstream bottom protection L,=(6 ^ -8) H;

Meanwhile, due to the high flow velocity in the measuring tank and the significant fluctuations in the water surface in the throat, it is difficult to directly measure the water level in the tank. Therefore, after setting up observation wells on the groove wall, measure the water level with a water gauge. The bottom of the well is 20-25cm lower than the groove threshold. The logging and measuring tanks can be connected by flat metal or concrete pipes, and the centerline of the pipes should be 3cm higher than the bottom of the tank. The upstream water gauge is located upstream of the throat at the beginning of the throat (2/3) A, and the downstream water gauge is located 5cm above the end of the throat on the tank wall. The detailed dimensions are shown in Figure 1-1. The zero point of the upstream and downstream water gauges should be level with the height of the groove bottom, and there should be no water leakage in the observation well. The well should be regularly cleaned of sediment and covered with a lid to prevent debris from entering.

　　Precautions

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

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.

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. (See the figure below)

The Bacher groove should be securely installed on the channel. The connection with the side walls and bottom of the channel should be tight and not leak water. Make all the water flow through the measuring part of the Bacher trough. The measuring part of the Bacher trough is the throat section inside the trough.

　　Basher Trough Structure Map