[Daily Question 200090409~10] What failures have the orifice plate flowmeter encountered when used on site, and how were they dealt with?
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What failures have the orifice flowmeter encountered during field use, and how were they dealt with? Format: Installation site: Fault phenomenon: Cause of failure: Treatment method: Due to server hard drive maintenance, this post will be closed one day later. I hope you all will continue to post! Pay attention to the post format, encourage originality, and do not spam. Original posts will add 10 wealth. Copying other people's posts and spamming posts will all reduce 10 wealth. This post was last edited by Mobei Yihai on 2009-4-9 21:09 ]
Installation site: Gas ammonia flow measurement failure phenomenon: Cause of failure of low measured value: Gas ammonia is measured using an annular chamber orifice plate. Since it is installed inside the process, the working pressure is low and the gas ammonia is not clean. Treatment method: The ring chamber will be cleaned during maintenance. The best method is to install it on the ammonia main pipe entering the process.
Installation site: Failure phenomenon of flange pressure standard orifice plate installed on medium pressure steam pipeline: After using it for a period of time, it was found that the measurement error was large, and during maintenance, it was found that the orifice plate was seriously worn. Cause of failure: Orifice plates are not suitable for medium pressure steam measurements because the temperatures are too high. Treatment method: It uses a standard nozzle and the material is 15CrMo that can withstand high temperatures.
Installation site: Superheated steam flow measurement failure phenomenon: Cause of failure of low measured value: .Designed as 1/4 round nozzle, delivered as sharp orifice plate ； Treatment method: After reinstalling it with a 1/4 round nozzle, it is normal.
Installation site: Carbon dioxide recovery device failure phenomenon: Original start-up, flow indication value is low, cause of failure: Orifice plate installation method: Take out the orifice plate and reinstall it correctly.
“Orifice plates are not suitable for medium pressure steam measurements because the temperatures are too high. ”This reason is untenable. Whether it is flange pressure measurement, nozzle or annular chamber pressure measurement, it is suitable for flow measurement of all steam series. Orifice plate wear may be due to incomplete pipe purging.
Installation site: Decarbonized ammonia liquid flow measurement failure phenomenon: During the water washing test run, the flow rate sometimes increases, but there is no cause of failure.: When washing the pipeline, due to the cleaning and discharge of sewage at the pump end, the gas and liquid are mixed when restarting, and there is also dirt in the pressure pipe. Treatment method: After opening the five-valve group drain valve, the drain is normal. Try not to test the remote transmission signal when washing. When driving, wait until the working conditions are stable before opening the pressure pipe.
Installation site: Failure phenomenon of flange pressure standard orifice plate installed on medium pressure steam pipeline: After using it for a period of time, it was found that the measurement error was large, and during maintenance, it was found that the orifice plate was seriously worn. Cause of failure: Orifice plates are not suitable for medium pressure steam measurements because the temperatures are too high. Treatment method: It uses a standard nozzle and the material is 15CrMo that can withstand high temperatures.
“The orifice plate is not suitable for medium pressure steam measurement because the temperature is too high." There is no theoretical basis!
Installation site: Failure phenomenon of boiler feed water flow pipeline in a methanol plant: The process reflection indication of a certain flow meter is inaccurate. After checking, the transmitter and secondary meter are normal, and there is no leakage at the joints. Compared with other flow meters, there is still a large error. It was never resolved while driving. Cause of failure: After parking the car and removing the orifice plate, we found that the orifice plate was very convex in the positive direction, and in the negative direction of the orifice plate, we saw a rough surface composed of countless pits. After analysis, it may be cavitation that causes the orifice plate to deform. Treatment method: Replace the orifice plate with the same model and the problem is solved.