Selection of orifice plates, nozzles, and Venturi tubes
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The selection of throttling devices such as orifice plates, nozzles, and Venturi tubes must be made by taking into comprehensive consideration their advantages, disadvantages, and practical application requirements. Generally, the following principles are followed: 1. Orifice plates, nozzles, and Venturi nozzles are typically used in pipes with a diameter D ≥ 50 mm. 2. To measure the flow rate of high-temperature, high-pressure media, orifice plates and nozzles are used; for example, orifice plates or nozzles are selected to measure steam flow rate ； Venturi tubes are only suitable for measuring the flow rate of low-pressure fluid media. 3. When a low pressure loss generated by the throttling device is required, nozzles or venturi tubes can be used. 4. Nozzles are a better choice when measuring the flow rate of certain dirty or corrosive media. 5. Among orifice plates, nozzles, and Venturi tubes, nozzles offer the highest measurement accuracy, and they also require a shorter straight pipe section. 6. In processing, manufacturing, and installation, orifice plates require the simplest design, nozzles are next in complexity, while venturi tubes are the most complex. 7. Subject to meeting the technical requirements, orifice plates, nozzles, and Venturi tubes shall be selected based on the principles of economy, suitability, and feasibility.
Based on your description, the selection of orifice plates, nozzles, and venturi tubes requires a comprehensive consideration of their respective advantages and disadvantages as well as the actual application requirements. Here are some basic principles: 1. Orifice plates, nozzles, and Venturi nozzles are typically used in applications where the pipe diameter D is ≥50 mm. 2. To measure the flow rate of high-temperature, high-pressure media, orifice plates or nozzles are commonly used, for example in measuring steam flow. Venturi tubes, on the other hand, are suitable for measuring the flow rate of low-pressure fluid media. 3. When a low pressure loss in the throttling device is required, nozzles or venturi tubes can be used. 4. If the medium being measured is dirty or corrosive, it is more appropriate to use a nozzle. 5. When comparing orifice plates, nozzles, and venturi tubes, nozzles offer higher measurement accuracy, and they also require a shorter straight pipe section. 6. During processing, manufacturing, and installation, orifice plates have the simplest requirements, followed by nozzles, while venturi tubes are the most complex to manufacture. 7. Subject to meeting the technical requirements, orifice plates, nozzles, and venturi tubes should be selected based on the principles of cost-effectiveness and feasibility. In short, the choice of throttling device should still be determined based on the specific application environment and requirements. .
This post was last edited by zhoudingshengs on 2023-11-22 09:35. 1. Classic venturi tube: Used for measuring the flow rate of various media, featuring low pressure loss, short requirements for straight pipe sections before and after it, and a long service life. Pressure tapping method: Special pressure tapping. Applicable pressure: 42.0 MPa. Applicable pipe diameter: 40–400 mm. Accuracy class: 0.8. Purpose: Used in various applications within the petrochemical industry where there are dirty fluids or fluids containing solids; it is particularly suitable for measuring and controlling wastewater in the coal chemical industry. 2. Tubular venturi: Used for measuring the flow rate of various media, it features low pressure loss, shorter required straight pipe sections before and after it, and a long service life. Pressure tapping method: Special pressure tapping. Applicable pressure: 42.0 MPa. Applicable pipe diameter: 350–800 mm. Accuracy class: 0.8. Purpose: Used for measuring and controlling the flow of large-diameter fluids under high pressure or in hazardous environments, in the petrochemical industry. 3. Venturi nozzle: Suitable for measuring various media, it features low pressure loss, shorter required straight pipe sections before and after it, and a long service life; its installation length is shorter than that of a conventional venturi tube. Pressure tapping method: Special pressure tapping. Applicable pressure range: 0.01–25.0 MPa. Applicable pipe diameter: 50–2000 mm. Accuracy class: 0.8. Purpose: Used for flow measurement and control in various large-diameter applications within the metallurgical industry.