The No.2 lubricate oil purifier on our ship has not been used for several years due to some problems. In the process of restoring its use, we have encountered various problems and we will introduce them to you. In order to solve the oil purifier problem in the future, it will help.
- Oil purifier model: Alfa Laval LOPX-705
- Control and monitoring device model: EPC-400
- Moisture sensor model: WT-200
1. Gearbox flooding
In the process of restoring the use of the No. 2 lubricate oil purifier, the problem of water in the gearbox was first discovered. In order to solve this problem, we have dismantled the oil purifier. Through inspection, it was found that the reason for the water ingress was that the protective plate under the paring disc device was corroded and rusted.
We know that the main function of the protective plate is to prevent leakage and discharge of water from the distributing cover and the bowl body into the bearing chamber and the gear box. The water at this place should pass through the venting groove on the body. Emitted. The gearbox was flooded due to corrosion and rust.
Since there was no such spare part at the time, we used a copper plate to make a protective cover and replaced the relevant sealing order, thus solving the problem of gearbox water inflow.
2. Can not build oil pressure
When the oil purifier started to start to enter the oil, it was found that there was no oil pressure. Check that the oil purifier supply pump and the separation cylinder are in a normal condition. Therefore, the reason for the low oil pressure is that the pneumatic three-way valve cannot be opened and the oil is still bypassing. In order to be confirmed, the three-way valve was manually opened, and the oil separation was normal.
In order to simplify the problem, it is more accurate to judge that the three-way valve is not working properly due to the three-way valve itself or its control mechanism. During the operation of the oil purifier, the air pipe joint at the top of the three-way valve is directly disassembled. As a result, no air pressure input was found. Therefore, it is judged that the problem is caused by the control solenoid valve MV1 (solenoid valve block, air), and the diaphragm is installed and reversed.
In addition, there is a test method: there is a manual switch on the control solenoid valve MV1. When the oil purifier is working normally, it is placed horizontally. If for some reason, it needs to be changed to manual operation, it can be at the beginning of the oil intake. Rotate the switch 90 degrees and place it in the vertical direction. At this point, air will be output to the oil supply three-way valve.
3. Not Sludge discharge
The oil separator was used less than one day, and there was no slagging. To solve this problem, I mainly look for two parts, one is the working water, and the other is the problem of the oil separator body.
The electromagnetic valve for controlling the slag discharge of this type of oil separator is MV16. The method to eliminate the problem is to loosen the connection pipe joint during the slag discharge process of the oil separator to observe whether the displacement and pressure are normal.
In the oil separator body, the factors affecting the slag discharge mainly include the operating slide and the nozzle condition in the dosing ring, and the condition of the paring disc device.
By disassembling the operating slide, we found that the seal caused a large amount of scale to exist in the tank, which directly affected the up and down movement of the operating slide. As a result, during the operation of the oil separator, the operating slide was operated. The card is stuck in the closed position of the nylon valve, and finally the sealing water under the sliding bowl bottom cannot be discharged, thereby affecting the slagging process.
4. A7-12 alarm, MV10A constant water
During normal operation of the oil separator, if the water in the separated absolute oil increases due to some reason, the EPC-400 will issue an A7-12 alarm after the moisture sensor (WT-200) is continuously triggered five times.
Obviously, the A7-12 alarm now shows that the moisture content in the net oil is already too high. What is the cause? The continuous phenomenon of MV10A gives us the answer.
We know that among the four valves on the solenoid valve block(water), the three valves MV10, MV15, and MV16 are normally closed, and the MV10A is normally open. The function of the MV10A is to release the back pressure from the separation cylinder to the solenoid valve body during normal operation of the oil separator to prevent the MV10 from opening abnormally.
Therefore, there is a continuous flow of water at the MV10A relief valve during normal operation of the oil separator, indicating that the MV10 solenoid valve has been abnormally opened (or closed), resulting in an increase in moisture in the clean oil. Due to the increase in moisture, the moisture sensor issued a slagging signal five times in a row, and finally the EPC-400 issued an A7-12 alarm. After dismantling MV10, it was found that due to the aging of the diaphragm, there were many cracks around the diaphragm, and as a result, the valve could not be closed. Depending on the situation, we replaced the valve top part to solve this problem.
5. A7-11, A7-1 alarm
The instructions indicate that the A7-11 alarm indicates that the displacement water is insufficient.
According to the oil purifier control principle, we know that during the oil purifier operation, at every ten discharges (ie, at the tenth slag discharge), the EPC-400 will perform a test on the displacement water volume, and automatically adjust the displacement according to the test result. Addition and subtraction of water quantity. If repeated tests are performed, no signal is added to the displacement of the water, and an A7-11 alarm will be issued. Due to this adaptation of the EPC-400’s operating conditions, the oil purifier is guaranteed to replace the normal amount of water during operation.
Obviously, the A7-11 alarm, the reason for the displacement water, MV10 is the replacement of the new spare parts, then you should first find the reason from the oil purifier. We found that the opening chamber nozzle was blocked by the oil purifier. (On the dosing ring, the upper nozzle is the open chamber nozzle and the lower nozzle is the closed chamber nozzle).
Through analysis, we understand that the blockage of the opening chamber nozzle will affect the discharge of the opening water. If the water cannot be completely drained, the nylon valve on the sliding ring will not be able to separate the cylinder. The drain valve under the bowl body is completely closed, and the end result is that the sliding bowl bottom cannot be completely closed, which causes leakage of displacement water from the slag discharge port in the separation cylinder (the oil may have occurred during this period). Happening). Due to the loss of displacement water, the moisture sensor detected a signal that the water volume was insufficient, and finally the EPC issued an A7-11 alarm.
After the nozzle problem is removed, the oil purifier is restarted, but just after the first slagging, the oil purifier issues an A7-1 alarm.
The meaning of A7-1 is that the moisture detected by the moisture sensor has exceeded the maximum value. According to the instructions of the manual, we have dismantled, cleaned and measured the moisture sensor. The output, input voltage, current and insulation of the oscillator meet the requirements except for a little dirty inside the sensor tube wall. However, after installing the moisture sensor, restart the oil purifier and still report the A7-1 alarm.
With this, we began to suspect that the water in the oil is really high. According to the control characteristics of this type of oil purifier, we turn P10 from 1 to 0, that is, enter the stand by mode. When the oil is separated in this mode, the water indication is basically the same as 280 units. This way we rule out the possibility of high water content in the oil.
At this point, we will go back and analyze the features of the stand by mode. When P10=0 is set, the system enters stand by mode and the system will:
- cutting off the alarm related to the moisture sensor.
- does not show the percentage of water content in the net oil reaching the trigger value.
- When running the P61 program, the slagging program controlled by the moisture sensor is cut off.
- Cut off the supply of displacement water/regulate water.
From the comparison of the results of the stand by mode operation and the above work characteristics, we made a judgment: the problem lies in the supply of replacement water. Because the first three cases of the stand by mode are restored when running in the on mode mode Will not cause an A7-1 alarm. Through further analysis, we can know that there are two main reasons for affecting the replacement water/regulating the water volume. One is the set time for the replacement water/regulation water, and then the valve itself.
To this end, we reviewed the working time of the replacement water/regulating water from the EPC-400. These set times are consistent with the specifications and are the same as the No. 1 oil purifier. Next, we measured and compared the water volume of the displacement water/regulate water of the two oil purifiers. It was found that the No. 1 water supply amount was about 1900 ml/m, and the No. 2 water supply amount reached about 3200 ml/m. It is far greater than the requirements of the manual. Therefore, we have again dismantled the solenoid valve. Soon we found that the aperture of the rubber ring that controls the flow rate on the original flow valve (0.9ml/m) is enlarged, although the flow valve body is marked with 0.9. Marked, but the actual traffic has far exceeded this value. To this end, we remade a rubber sheet according to the rubber ring prototype, and punched the center hole with a 1.5 mm drill at the center. The flow rate was about 1500 ml/m.
After installing the solenoid valve, start the oil purifier to work, everything is normal. At this point, the problem of the No. 2 oil purifier has been completely solved.
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