Can large-diameter low-pressure gas pipelines be measured using differential pressure?
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Can large-diameter low-pressure gas pipelines be measured using differential pressure? DN900, pressure of 5 KPa, flow rate under standard conditions of 17,000 NM3/h. Is 5 KPa not sufficient to create a pressure difference? In such a case, is it necessary to reduce the diameter of the pipe before installing a throttling element to generate a pressure difference?
The pressure difference is significant; it mainly depends on whether there is a suitable throttling element, and Enova is generally used for this purpose
Both an average velocity tube and a Venturi tube work.
For large-diameter, low-pressure applications, our thermal gas mass flow meters are the best choice: they offer high precision, a wide measurement range, no pressure loss, and enable direct measurement of the instantaneous flow rate under standard conditions. At the China Academy of Space Technology, the working pressure is only 5 Pa, and our thermal mass flow meters are used there.
Dude, how do you guys solve the problem of dirty heat systems?
Generally, for large-diameter pipes with low flow rates, bar-type flow meters are used. For orifice plates, you can ask the manufacturer to carry out calculations; they cannot be used if the pressure loss is too high. In such cases, reducing the pipe diameter is not an option
This seems to be related to the flow rate of coke oven gas; a V-cone can be used for this purpose, as the principle involved is also one of reducing the diameter. Pressure transmitters are likely not suitable for use here, as it’s difficult to ensure accuracy
Stop talking nonsense; the V-cone doesn’t work here – only a uniform velocity tube or a Venturi tube can be used.
Is that so? I’ve used it for 10 years too; how is it not useful? Tell me about it
The operating condition here is DN900 with a flow rate of 17,000 nm3/h; in my opinion, for such a large pipe diameter, the flow rate is a bit low. Objectively speaking, the differential pressure range of average velocity tube flowmeters (i.e., Pitot-type meters) is relatively small, which may affect their measurement accuracy. With an orifice plate, the pressure loss is approximately 0.6 kPa; with a Venturi, it is about 0.15 kPa; and with a V-cone, it is roughly 0.5 kPa. If the pressure loss associated with the V-cone is acceptable for this application, then why not use an orifice plate? Moreover, the volume of the V-cone is large, and the volume of the venturi is also significant. The measurement principle is similar to that of the V-cone and the venturi, but the venturi is more widely used and comes with a range of standard specifications – so why not use the venturi? Of course, since you have been using the V-taper for many years and it works well, then keep using it.