Flow meter selection
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I’m new to instrumentation and don’t know much about it. There’s a specific application scenario for which I need to select a flow meter, and I would appreciate everyone’s help in making this decision. The medium is steam; the temperature is 180°C, the pressure is 0.5 MPa, the pipe diameter is DN200. The operating flow rate is 400 Kg/h, the maximum flow rate is 1000 Kg/h, and the minimum flow rate is 200 Kg/h. There is a control valve in front of the installation location, and currently, the flow rate is controlled manually using this valve. Given these parameters, it is suggested that an orifice plate flow meter be used. But I wonder whether an orifice plate can accurately measure the flow rate given the large pipe diameter and relatively low flow rate Or could anyone recommend what kind of flow meter would be good?
It has a large diameter but low flow rate; this type of flow meter isn’t very suitable for selection. ，，，，，，，，，，，，，
It is recommended to use orifice plates; some pressure loss can be accepted as part of the process involving diameter reduction
Well, I’m currently considering installing a reducing orifice plate. I was wondering if there are any requirements regarding the straight pipe sections needed for its installation? What are the things to pay attention to? Seeking advice from experts
There is no problem using an integrated orifice flow meter; orifice flow meters are relatively accurate.
There is a valve at the front end; the straight sections before and after the flow meter may need to be larger – 50D in front and 5D behind, I think. These are just my opinions; please point out any mistakes
The pressure is 0.5 MPa and the temperature is 180°C; it is not saturated steam but superheated steam, so temperature and pressure compensation are necessary. The pipe diameter is large while the flow rate is low, with a ratio of maximum to minimum flow rate of 5:1. Orifice plates are not suitable for this application; vortex flow meters could be considered instead. Vortex flow meters require protection against vibration, and it is best to install them at a distance from the control valve. Reducing the pipe diameter during installation might also be an option~~~
The control valve mentioned by the poster is probably a flow control valve. Why not install it behind the flow meter? That would be better; it’s sufficient to ensure that the pipe sections before and after the flow meter are 10D and 5D in length respectively, with as little vibration as possible! My humble opinion...
The control valve on the pipeline is a standard plug valve, a purely manual valve. Initially, it was planned to use a vortex flow meter, but the company’s management preferred to use orifice plates for easier calibration; this is because the company has the qualifications to calibrate orifice plate flow meters. . . . . .
It is recommended to choose an intelligent integrated orifice plate flow meter with temperature and pressure compensation; it features an LCD display for showing instantaneous and cumulative mass flow rates, as well as temperature and pressure values, and it outputs a signal of 4-20mA, powered by 24VDC. http://www.shakic.com/cp/product7.htm
It is recommended to use a nozzle for necking, as it results in low pressure loss and prevents liquefaction； The minimum Reynolds number is also low, which is better than orifice plates