Guangzhou Haoyi customizes instruments for you---Huizhou open channel flowmeter, ultrasonic open channel flowmeter

New appearance intelligent [Dongguan Split Open Channel Flowmeter] Open Channel Flowmeter Discount Guangzhou Haoyi Open Channel Flowmeter Principle Description/Open Channel Flowmeter Industrial Procurement Haoyi Series Parshall Tank Open Channel Flowmeter consists of an instrument for measuring liquid level and a metering The water tank made of documents published by the institute is composed of two parts. The liquid level meter directly measures the liquid height in the channel or water tank. When used to measure flow in an open channel, a measuring weir should be installed on the open channel. Measuring weirs convert the flow rate in the open channel into liquid level. The instrument measures the water level in the measuring weir and trough, and then calculates the flow rate according to the water level-flow relationship of the corresponding measuring weir and trough. , The principle of ultrasonic liquid level measurement is to transmit the ultrasonic pulse emitted by the ultrasonic transducer, which propagates to the liquid surface to be measured through the propagation medium. After reflection, it returns to the receiving transducer through the sound transmission medium. The ultrasonic pulse is measured from transmitting to receiving. The time of propagation in the sound transmission medium. Then according to the speed of sound in the sound transmission medium, the distance from the transducer to the liquid surface can be calculated. This determines the liquid level. Therefore, we can calculate the distance from the probe to the reflecting surface */ (divided by because the sound wave actually goes back and forth from emission to reception, which is the distance, the speed of sound, and the time). The liquid level value can then be obtained by subtraction. , The flow measurement principle of the water measuring weir tank is that the greater the flow rate in an open channel with smooth flow, the higher the liquid level, the smaller the flow rate, and the lower the liquid level (as shown in the figure). The flow rate can be deduced by measuring the water level. The corresponding relationship between flow rate and water level in an ordinary open channel is affected by the slope ratio of the channel and the roughness of the surface. Installing a water measuring weir and trough in the channel will produce a throttling effect, so that the flow rate in the open channel has a fixed corresponding relationship with the liquid level. This correspondence mainly depends on the structural size of the water measuring weir and trough, so as to minimize the influence of the channel. Small. Commonly used measuring weirs and troughs include right-angled triangular weirs, rectangular weirs and Parshall troughs (as shown in the figure). When using a Parshall trough open channel flowmeter, you must know the water level-flow correspondence relationship of the water measuring weirs and troughs when installing. Once the throat width b of the Parshall trough is known, the corresponding relationship between water level and flow rate can be calculated using the corresponding formula. Right-angled triangular weirs also use corresponding formulas to calculate the water level-flow corresponding relationship. Rectangular weirs also have corresponding formulas. But it is also related to the size of the installed channel. When determining the water level-flow relationship, the rectangular weir is related to the channel width B, the opening width b, and the height of the upstream weir sill. If you are not familiar with calculating the water level-flow rate of the weir and trough, you can inform our company of the parameters of the weir and trough used and we will help with the calculation. Care should be taken to also provide the parameters mentioned above that are relevant for determining the water level-flow relationship. 3. When choosing the type of water measuring weir and trough, we must consider the size of the flow rate in the channel, the flow pattern of the water in the channel, and whether free flow can be formed. Depending on the large flow rate, we can choose different weirs and grooves. ① If the large flow rate is less than liters/second, it is recommended to use a right-angled triangular weir. ② If it is greater than liters/second, it is recommended to use a Parshall trough. ③ The upstream channel is short, and the large flow rate is greater than liters/second. It is recommended to use a rectangular weir. If conditions permit, it is best to choose the Parschel tank. The water level-discharge relationship of the Parshall tank is calibrated by the laboratory, and the requirements for the upstream channel conditions are weak. The water level-flow relationship of triangular weirs and rectangular weirs is derived from theoretical calculations, which may easily lead to additional errors due to ignoring some usage conditions. Use fiberglass to make water measuring weirs or troughs. The size of the weir mouth of triangular weirs and rectangular weirs must be accurate, and the surface on the side facing the water inlet must be smooth. The size of the throat part of the Parshall trough must be accurate and the inner surface of the trough must be smooth. 4. Physical drawings of on-site open channel weir and trough installation ◆ Triangular weir installation ◆ Rectangular weir installation ◆ Parshall trough installation 5. Installation of water measuring weir and trough ①. The center line of the water measuring weir and trough should coincide with the center line of the channel to allow water to enter There will be no deviation in the water measuring weir and groove. ②. After the water measuring weir channel is filled with water, the flow pattern of the water should be free flowing. The water level downstream of triangular weirs and rectangular weirs should be lower than the weir sill, and the submergence degree of the Bashere trough should be less than the critical submergence degree of the "Baschel trough parameter". ③. The upstream end of the water measuring weir and trough must have a straight section larger than twice the width of the channel, so that the water flow can enter the water measuring weir and trough smoothly. The standard is "no waves on the water surface". That is to say, there is no left and right bias flow, and there is no impulse caused by the slope of the channel. ④. The water measuring weir and trough must be installed firmly on the channel. It must be tightly connected to the side wall and bottom of the channel to prevent water leakage. Make all water flows through the metering part of the measuring weir and groove. The measuring part of the water measuring weir plate is the weir mouth and the measuring part of the measuring water tank is the throat section in the tank. 6. Selection instructions: Dazzle series Parshall trough open channel flowmeter code weir trough type B Parshall trough (indicate the number of troughs) Triangular weir (indicate the angle) Rectangular weir (indicate the width of the weir mouth) Code liquid level probe Type Integrated split type (standard meter cable) Coded liquid level probe material (all explosion-proof) Ordinary type (polyoxymethylene) Anti-corrosion type (polytetrafluoroethylene) Enhanced type (polytetrafluoroethylene + extended functions, such as communication, relay output, etc. ) Selection example: The highest on-site flow rate range is tons/hour, and the common flow rate is tons/hour. The customer wants to choose a Parshall tank. The liquid level probe is split type. The sewage is neutral, normal temperature, and has no volatile gases. 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