How to maintain a orifice meter for measuring hydrogen gas
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The pipeline pressure is 15 MPa, but the gauge reads zero. How should it be repaired?
No ethylene glycol? I’ve seen those handheld pressure devices and things like that.
I don’t understand what you mean. Do you think the amount isn’t right?
There is pressure in the pipeline, but flow may not be present; therefore, the gauge might also read zero. First, it is necessary to determine whether there is any flow.
Check whether the orifice plate is installed properly, and whether the straight pipe sections before and after it meet the requirements! Check again to see if the high and low pressure sides of the orifice plate and transmitter are installed in reverse! !
The flow measurement medium must have a certain flow velocity in the pipeline in order to create a pressure difference before and after the orifice plate, thereby generating a flow rate. There is pressure in the pipeline but no flow; it is estimated that the valve on the user side is closed, preventing the medium from flowing and resulting in static pressure within the pipeline. So, although there is pressure in the pipeline, there is no flow. Hydrogen is an extremely clean gas, with a very low possibility of blockage. Even if there is an installation issue, a certain amount will still be displayed. Assuming there is no fault with the testing equipment, check the valve behind the throttle element.
Flow rate is independent of pipeline pressure and is related to differential pressure.
Check whether there are shut-off valves in the upstream and downstream sections to ensure flow is stopped, and why an orifice plate is used for hydrogen measurement given the low density of the medium.
The orifice plate measures the pressure difference between two pressure sampling points; it has nothing to do with the pipeline pressure. Check whether the valve at the root is open, and allow a small amount of fluid to flow out to balance the pressure. Is the balance valve also open?
It is common for there to be pressure in the pipeline but no flow; one can open the balance valve to check whether the positive and negative drain valves are functioning properly. The balance valve can also be opened, the pressure measurement stop valves for positive and negative pressures can be closed, and the transmitter can be removed for calibration.
Pipe pressure and flow rate aren’t closely related, right? Pressure doesn’t necessarily mean there’s flow. Check whether there are any valves before and after the pipeline that are open or closed, as well as the on/off status of each valve in the instrument’s valve assembly. Try blowing air out using the exhaust and drain valve to see if there is a blockage, and check whether the differential pressure measured by the instrument is normal. Installation issue: are the straight sections at the front and back appropriate?