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This post was last edited by wx_J08L3 on 2023-3-22 at 15:20. Depending on the properties of the medium being measured, as well as factors such as pressure rating, temperature rating, the diameter of the user’s pipeline, installation method, and pressure tapping method, orifice plate flow meters can be classified into standard orifice plate flow meters, integrated orifice plate flow meters, annular orifice plate flow meters, welded orifice plate flow meters, notched orifice plate flow meters, embedded orifice plate flow meters, lens-type orifice plate flow meters, balanced orifice plate flow meters, eccentric orifice plate flow meters, conical-inlet orifice plate flow meters, flow-limiting orifice plate flow meters, gas extraction orifice plate flow meters, and mine-use orifice plate flow meters, among others. The orifice plate flow meter is a differential pressure flow measurement device with a high range ratio, consisting of an orifice plate for throttling along with a multi-parameter differential pressure transmitter (or separate differential pressure transmitter, temperature transmitter, and pressure transmitter). It can measure the flow rate of gases, steam, and liquids, and is widely used in process control and measurement across various fields such as petroleum, chemicals, metallurgy, power generation, light industry, textiles, scientific research, military industry, heating, and water supply. Uses, features, and application scope of orifice plate flow meters: 1. Uses: Throttling differential pressure flow meters consist of three components: a throttling device, a differential pressure transmitter, and a flow integrator. Throttle devices are primary components that are installed directly on the pipeline, while differential pressure transmitters and integrators belong to secondary components. It is mainly used for various gases (pure or dusty) flowing through pipes, steam (saturated or superheated), and liquids (conductive or non-conductive) ； High corrosivity ； Flow rate of viscous or dirty substances containing fine particles. It can directly measure volumetric flow rate or mass flow rate. 2. Operating conditions, characteristics, and application range of differential pressure flow meters (standard orifice plates) a. Operating conditions: 1. In the measurement section, the fluid must fill the circular tube and flow continuously through the throttling device ； 2. The fluid must be a homogeneous single-phase fluid in terms of physics and thermodynamics ； 3. The fluid measured by the throttling device must be a steady flow, or one that can be considered as a steadily changing flow; it is not suitable for measuring pulsating flows or critical flow rates ； b. Characteristics and scope of application: 1. Standard throttling devices can ensure their measurement accuracy without the need for actual flow calibration. 2. It is applicable to a very wide range of media to be measured, and can be used for flow measurement of almost all gases, vapors, and liquids ； 3. It is applicable to pipes with a diameter ratio β of 0.22~0.75 and a Reynolds number ReD ≥ 5000, for pipe diameters ranging from DN50 to 1000 mm; extrapolation to 5000 mm is allowed. β=d/D, where d is the diameter of the orifice in the plate ； D—Actual inner diameter of the pipe. 4. The operating pressure can reach up to 32 MPa; it can also be used for negative pressure ； 5. Medium temperature range: -30°C to +650℃ ； 6. The intelligent differential pressure flow meter uses an intelligent differential pressure transmitter; it allows the differential pressure value to be set on-site via buttons or communication methods (within specified ranges), in response to changes in the flow rate of the fluid being measured. This enables the adjustment of the flow rate range, thereby **expanding the system’s flow rate coverage** ； 7. No moving parts – the mechanism is safe and reliable; it is simple to use and operate, easy to master, and requires no maintenance. 14 technical parameters of the integrated throttle orifice plate flow meter: 1. Diameter: DN25～DN1000 (mm) 2. Accuracy: ±1%FS 3. Range ratio: Standard 1:13, Extended 1:30 4. Operating pressure: ≤42.0MPa 5. Medium temperature: -40oC～450oC 6. Medium viscosity: ≦30CP (equivalent to heavy oil) 7. β value: 0.2～0.8 8. Connection method: Flange or clamp type 9. Flange standard: DN≤600mm, PN2.0～PN26, HG20616; PN32, HG20618 ； DN>600mm, PN2.0～PN15, HG20623; it can also be manufactured according to the flange standards provided by the user. 10. Material: Body, orifice plate, pressure tapping tube, three-valve assembly: stainless steel ； Straight pipe sections and connection flanges: carbon steel or stainless steel. 11. Installation method: horizontal or vertical. 12. Intelligent differential pressure transmitter: Output: 4–20mA.DC or digital signal ； Power supply: 24V.DC; 13. Explosion protection rating: dⅡCT5.6, iaⅡCT4-6; Protection rating: IP67. 14. Gauges: available in both blind gauge and digital display types. Pipeline conditions for installing orifice flow meters: (1) The straight sections before and after the throttling element must be straight, with no visible bends. (2) The straight pipe section used for installing the throttle element should be smooth; if it is not smooth, the flow coefficient should be multiplied by a roughness correction factor. (3) To ensure that the fluid flow develops a fully developed turbulent velocity profile 1D in front of the throttle element, and to make this profile uniformly axially symmetric, 1. the straight pipe section must be circular; moreover, within a range of 2D in front of the throttle element, high precision is required regarding its circularity, with specific circularity criteria to be met. Specific measurement method: (A) At the four vertical pipe sections of OD, D/2, D, and 2D in front of the throttle element, at least 4 individual measurements of the inner diameter of each pipe are taken at roughly equal angular intervals, and the average value D is obtained. The difference between any individual inner diameter measurement and the average value shall not exceed ±0.3%. (B) Behind the throttle element, 8 individual inner diameter measurements are taken at the OD and 2D positions using the aforementioned method; the deviation of any individual measurement from D shall not exceed ±2%. 2. A sufficiently long straight pipe section is required before and after the throttle element, and the length of this straight pipe section depends on the type of local resistance element prior to the throttle element as well as on the diameter ratio β. (4) The length of the straight pipe section between the resistance element on the upstream side of the throttle element and the subsequent resistance element can be taken as 1/2 of the value listed, based on the configuration of the second resistance element and with β=0.7 (regardless of the actual value of β). (5) When the area upstream of the throttle element is an open space or a large container with a diameter of ≥2D, then the length of the straight pipe between that open space or large container and the throttle element must be at least 30D (15D). If there are other local resistance elements between the throttle element and the open space or large container, then in addition to a straight pipe section of specified length 1 being provided between the throttle element and those local resistance elements, the total length of the straight pipe section from the open space to the throttle element must also be at least 30D (15D).