Level gauge abnormal
我的维修经历 --- My repair experience
The rainy season has been coming for more than half a month, and the air is extremely humid.
The liquid level here has repeatedly failed, and the float transmitter has been changed several times in more than half a month. During Tuesday night shift handover, the transfer record also recorded that the level gauge was inaccurate. The master has repaired it this morning.
In the afternoon I was studying, the phone rang, and the master was away. I answered the phone. --- 算了，还是自己去吧。 The master didn't know where to go again. Look at all the bullish masters around --- forget it, let's go by yourself.
37 度以上，湿气又大，下午异常闷热。 There was a heavy rain yesterday night. Today the sun is very good, the temperature is above 37 degrees, the humidity is heavy, and the afternoon is extremely sultry.
2 ： 00 之前一直小幅波动，在 2 ： 10 分突然有一个阶跃跳跃，后有稳定一段时间后，就开始大幅波动，波动周期不固定，波动输入那种大幅跳跃的毛刺性质，一会大一会小。 I came to the control room and looked at the real-time and historical trends. I saw that the liquid level fluctuated slightly before 2:00 , and suddenly there was a step jump at 2:10. After a period of stability, it began to fluctuate greatly. The fluctuation period is not fixed, and the glitch nature of the large jump of the wave input may be larger or smaller.
After greeting the operator, I went to the site to check. 2 米，在塔盘扶栏附近， After arriving at the scene, it was found that the installation level of the float ball level gauge was more than 2 meters. I went to the scrap yard and carried a channel steel to the handrail and the wall. 40% 突然变成 18% 。 Go up and check. As soon as the pointer touches the meter head, it suddenly changes from 40% to 18% .
From the float check:
I lifted up the weight to check the float zero and range, and the display was normal.
Look at the connection of the floating ball shaft connector tightly, there is no looseness.
Then look at the bearing of the floating ball transmitter , and see if it can be turned, it should not have much friction.
The float transmitter is a new one, because the master has just changed it during the previous repairs.
Checking the seal of the floating ball is also ok. In the floating ball counterweight, the floating ball shaft is flexible, and it can be determined that the friction of the packing is not large.
Check the floating ball fixing plate, it is also very strong.
20% 左右，上行程、下行程都很好，观察了几分钟，其液位显示也没出现波动。 The liquid level of the counterweights that has been reciprocated several times has always shown about 20% , and the upper and lower strokes are very good. After a few minutes of observation, the liquid level display did not fluctuate.
The sweltering air and the radiation from Tabby made me impatient and sweaty. I decided to withdraw and tell the operator to fix it.
Just after I got off the escalator, I suddenly thought that it was raining that caused the pipe to leak? Caused by power supply short circuit?
Don't worry, there is a connector in the middle of the cable, which is short-circuited by blisters.
I opened the junction box, checked that there was no water, and checked that the wiring connections were secure.
Remove the wiring and remove the explosion-proof hose. The cable conduit runs vertically downward from the top of the instrument, passes through the upper tray and connects to the instrument through the explosion-proof hose.
During the disassembly process, dirty water flows out, which is dark and smelly. After disassembly, a lot of black, red and dirty water flowed out. Wipe the cable with labor protection gloves to see if there is any damage to the connector and cable insulation. Everything is normal.
Reinstall the explosion-proof hose wiring again. This process wastes a lot of time, because the hose is aging, the plasticity is poor, it is difficult to thread the wire, and it is difficult to connect the wire.
There was some remorse in my heart, and I hated myself for being suspicious and causing myself to suffer.
Pack up your tools and get down to leave.
---- 浮球指针又大幅波动，到了 48% 。 Before you leave, you can still rest assured, look up, and rely on the float pointer to fluctuate sharply, reaching 48% .
20% ，于是感觉是浮球变送器的问题，需要更换。 I was annoyed, climbed up again, and returned to 20% , so I felt that it was a problem with the floating ball transmitter and needed to be replaced.
----- Thinking on the road, is there a problem with the quality of the float transmitter? I have also changed a few this month -----
Back to the instrument warehouse near the operating room, I checked that several of them have been replaced, and there are no new spares.
So he returned to the scene and decided to disassemble it online to see what was wrong with its transmitter.
Since the transmitter is new, it is relatively smooth during disassembly, and it is easy to remove the panel indicating connection plate.
See internal circuits and devices.
First look at the wiring, there are no virtual soldering and loose places.
Next, check that the rotating shaft of the wave counterweight scoring transmitter rotates well, the pointer on the panel is normal, there is no problem, and it is helpless to re-fix.
Because the panel is fixed vertically on the case of the floating ball, the four screws are easy to install on the ground, but vertical installation is a bit difficult on the spot.
It took a long time to finally install the fastening. Up to the last screw, when the upper part of the panel is close to the broadcast button on the panel, the pointer suddenly fluctuates sharply, and the screw pointer returns to normal again. After disassembling the panel, it turned out that the solder joints of the wiring of the button switch were close to the panel terminals of the case. Due to the high humidity, the circuit was short-circuited.
Then remove the two screws on the upper part, and only fix the panel with the two screws on the lower part. This will not cause a short circuit.
After repairing, this meter has experienced the entire rainy season and has been operating normally. It has been half a year now and has not failed.
Occasionally, when I was okay, I checked the disassembled floating ball transmitters again , and they were all defects. They were rectified and used again, and the results were good. Ha ha.