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A orifice plate flow meter consists of a throttling device and a differential pressure gauge, or it is composed of a throttling device and a differential pressure transmitter together with a secondary instrument. Orifice plate flowmeters have a long history of use, and they are standardized both internationally and domestically. A orifice flow meter is the primary element used in differential pressure measurement; it is employed to create a pressure difference in a fluid within a pipeline. A pressure guide tube is used to transmit the pressure difference generated before and after the throttling device to the differential pressure transmitter, which then feeds the data to the secondary instrument, thereby displaying the instantaneous or cumulative flow rate of the fluid in the pipeline. The flow rate can also be adjusted using control instruments. The throttling device has a simple structure, accurate measurement, reliable performance, and is easy to repair and maintain. Working principle of orifice plate flow meter The orifice plate flow meter creates throttling artificially within the pipe through which the fluid flows. When the medium under test flows through the throttling device, it causes a local contraction; as a result, the flow becomes concentrated, the flow velocity increases, and the static pressure decreases. This creates a difference in static pressure on the upstream and downstream sides of the orifice plate. There is a certain functional relationship between this static pressure difference and the flow rate; the greater the flow rate, the greater the resulting static pressure difference. Therefore, the flow rate can be determined by measuring this pressure difference. Structural features of orifice plate flow meters: 1. Orifice plate with pressure tapping in the annular chamber: By utilizing pressure tapping in the annular chamber, measurement accuracy is improved, and the minimum length of straight pipe required for installation is reduced, allowing its widespread use in various industries. 2. Standard orifice plates with individually drilled holes for corner connections: This type is commonly used when the pipe diameter is 400 millimeters or more. The pressure sampling methods include drilling a hole separately on the flange for sampling, or using a circular or square pressure equalizing ring for sampling. The orifice plate type can be a handle-equipped orifice or a non-standard elliptical orifice plate, etc. 3. Flange-type pressure-taking orifice plate flow meter: Regardless of the pipe diameter, the centers of the pressure-taking holes upstream and downstream are located at a distance of 25.5 mm from both end faces of the orifice plate; this type is widely used in oil refining systems. 4. Standard orifice plate for diameter measurement: The pressure sampling method is pipeline-based sampling. The center of the upstream pressure tap is located at one diameter of the pipe in front of the orifice plate. The center of the downstream pressure tap is located at a distance of half the inner diameter of the tube from the rear end face of the orifice plate. 5. Small-diameter orifice plates: Non-standard orifice plates used for measuring fluids in pipes with diameters ranging from 10 millimeters to 50 millimeters. 6. Dual orifice plate: It consists of two standard orifice plates that are installed at a certain distance from each other within a straight pipe. In terms of the flow direction, the holes at the front are referred to as auxiliary orifice plates, while the orifice plate at the back is called the main orifice plate. The cross-sectional ratio m1 of the auxiliary orifice plate is greater than the cross-sectional ratio m of the main orifice plate. Two orifice plate flowmeters form a nozzle similar to one with a liquid wall. It is used for flow measurement in low-Reynolds-number fluids or high-viscosity fluids. 7. Orifice plates with variable apertures: These are non-standard orifice plates suitable for measuring the flow rate of fluids that are dirty, contain bubbles, or have solid particles in them; however, their measurement accuracy is relatively low. 8. Conical inlet orifice plate: A non-standard orifice plate. The circular cone forms a 45° angle with the centerline; this conical inlet orifice plate can be used in situations with very low Reynolds numbers, provided that the pipe diameter is at least 25 millimeters. 9. Others. Features 1) Standard orifice plate--it features high measurement accuracy, easy installation, a wide range of applications, and low cost. Widely used for flow measurement in various media. 2) Standard nozzle -- features resistance to high temperatures and pressures, impact resistance, a long service life, a wide measurement range, and high measurement accuracy. Suitable for measuring the flow rate of high-temperature and high-pressure steam in power plants, as well as in heating network pipelines, for fluids with high flow velocities. It comes in two forms: A: Nozzle (standard nozzle); B: Long-neck nozzle. 3) Classical venturi tube venturi nozzle -- characterized by low pressure loss, high measurement accuracy, short straight pipe lengths before and after, and a long service life. For more information, please visit the company’s official website at http://www.yb1518.com/. Please keep this link when reproducing the content! http://www.yb1518.com/UploadFiles/2012118173632146.jpg