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The flow nozzles are used for flow measurement at high fluid velocities and are more rugged and more resistant to erosion than the sharp edge orifice plate. Basically, there are two types of flow nozzle, the long radius flow nozzle and the I.S.A. (International Federation of the National Standardizing Association) flow nozzle. A Flow Nozzle consists of convergent inlet whose shape is the quarter ellipse, and a cylindrical throat. D.P. measurement taps are normally located one pipe diameter upstream and ½ diameter downstream from the interfaces of the nozzle. For a given diameter and a given D. P., it allows measurement of flow rates almost 65% more than that of the orifice plate.
Flow nozzles are commonly manufacture from material such at SS or crome-moly steel. They are made commercially in various configuration, viz. Flange type, Holding ring type, Weld in type and Throat type.
It should be used at Reynolds numbers of 50000 or above. However, data is available for Reynolds numbers down to 6000, so it is possible to use nozzles with more viscous fluids. It has very high coefficient of discharge, typically 0.99 or greater, and a wide range of beta ratios of 0.2 to 0.8.
Flow Nozzle Advantage
- Permanent pressure loss lower than that for an orifice plate.
- Available in numerous materials.
- For fluids containing solids that settle.
- Widely accepted for high pressure and temperature steam flow.
Flow nozle Disadvantage
- Cost is higher than orifice plate.
- Limited to moderate pipe size
- Requires more maintenance (it is necessary to remove a section of pipe to inspect or install it .
Flow Nozzle Application
- It is used to measure the flow rate of a liquid released into the atmosphere.
- It is commonly used in the situation where suspended solids have the property of settling.
- Widely used for high pressure and temperature steam flow.
- Orifice meter | orifice meter is used to measure
- Different Type Flow element
- Venturi Meter
- Magnetic Flowmeter