Which instruments need to be removed during pipeline pressure testing and purging?
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The pipeline is currently equipped with the following instruments: 1. Several thermal resistors； 2. 1 EJA530 pressure transmitter ； 3. 5 EJA118E double-flange level gauges ； 4. 1 vortex flow meter ； 5. 6 control valves ； 7. 1 Coriolis mass flow meter ； 8. 1 orifice plate flow meter ； 9. 4 Bourdon tube pressure gauges. What components should be removed during pressure testing and purging? In my opinion, those that should be removed during pressure testing are: 3, 5, 7, 9 ； Items that should be removed during purging are: 2, 3, 4, 5, 6, 7, 8; all of them should be replaced with short pipes. I’m not sure if this is correct, so I hope experienced users can give me some advice!
There is no need to disassemble the level gauge; it is sufficient to remove the orifice plate, flow meter, and control valve
For level gauges, pressure transmitters, and spring pressure gauges, you just need to close the root valve; as for temperature sensors that have protective casings, there’s no need to worry about them. All that needs to be dealt with are the flow meters and control valves
During purging, debris such as slag inside the pipeline may scour the instruments installed on it, leading to their damage. The thermoresistor already comes with a protective sleeve, so there is no need to remove it. If a manual valve is installed in front of the pressure transformer, simply close the valve ； The double-flange level gauge was removed; the flange diaphragm is prone to erosion and wear, so the flange area was covered with a blind plate ； Remove 4, 7, and 8, and connect them with short pipes ； When purging the control valve, it is sufficient to leave it fully open; there is no need to disassemble it. After all, both pressurization and purging take place over a short period of time, so they have little impact on the valve ； 9 is the on-site pressure gauge; a one-piece manual ball valve should be installed in front of it, and shutting off that valve will suffice. I didn’t see your 5; did you miss it?
It’s 6, not 5; was 6 missed?
Coriolis mass flow meter, control valve, level gauge.
Mainly, the flow meters (vortex flow meters and mass flow meters) and control valves need to be removed; as the orifice plates in orifice plate flow meters have not yet been installed, there is no need to worry about them at this time.
The valve must be removed, as during purging a large amount of impurities continuously strike the valve core and seat, causing significant damage to them. In the case of a cage-type control valve, debris can block the small holes in the sleeve, causing abnormal valve operation. The double-flange transmitter must be removed, as the diaphragm box is prone to damage. It is recommended to remove the flow meter to prevent damage to the measuring elements. Other options include shutting off the root valve.
Our self-control guideline is: remove/close the instruments during purging, and try to conduct pressure testing together with the pipeline equipment； The specifications for pressure vessels/pipelines require that the instruments be removed ； In fact, the testing pressure for pressure pipes/equipment far exceeds the range of our instruments or the pressure tolerance of the flanges; even 2-3 times the upper limit of the pressure gauge’s range is not sufficient. Therefore, it depends on the testing pressure, and in most cases the equipment has to be disassembled