About pump mechanical seal flushing plan
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Dear friends, as a designer, we updated a residual oil pump for the owner. The temperature is about 150 degrees. Due to the high viscosity of the medium, we began to recommend the owner to use a positive displacement pump. However, the owner said that the several centrifugal pumps in use were in good operating condition, so according to the owner's wishes, we also chose a centrifugal pump this time, and in the end it was the same manufacturer as the several pumps in use. According to the technical agreement, the manufacturer's mechanical seal flushing plan is Plan32, which should use the same medium as the external flushing source. Considering that there are many residual oil magazines, it is not suitable for flushing, and there are no oil products such as gasoline and diesel nearby. The manufacturer also claims that the pump provided this time is the same as the current one. The pumps used in the field are the same. After providing photos of the scene to the manufacturer, the manufacturer said that the pumps in use are all connected to cooling water. We really don’t know much about this aspect, and subjectively believe that there will be no problems as in the field, so the external flushing source is connected to the cooling water. Now there is a problem. During the trial operation, the owner found that the cooling water connected to the external flushing source at the shaft seal would condense directly out of the pump body. Does this mean that the cooling water directly enters the pump cavity? If this is the case, it is obviously inappropriate. It would have already vaporized at more than 100 degrees. We did not expect that the cooling water would directly enter the pump chamber. Is this what Pl32 looks like? How should we remedy this situation now?
When the pressure in the pump chamber is higher than the saturated vapor pressure of water at 150 degrees, it will not vaporize. The pressure of the 32 system is about 2 kilograms higher than the pressure in the pump chamber, so it is normal to have water in the discharge condensate.
This post was last edited by 1070273960 on 2016-9-14 15:07. First, I will introduce the 32 flushing plan.: The mechanical seal friction pair is flushed with external materials that are compatible with the transport medium. The flushing fluid pressure is about 2 kg higher than the transport medium pressure. Therefore, the flushing fluid will enter the transport medium, that is, the pump. The amount of entry is about 6-10 liters/minute. The 32 plan for external flushing of the residual oil pump is definitely not flushing. Even if water can be used for flushing, I guess the customer will not agree. The flushing fluid must be compatible with the medium. The customer said that the water they always use should not be the 32 plan but the 62 plan (the back of the static ring of the flushing machine is sealed to prevent carbonization and crystallization)
I work in pumps and have a lot of contact with mechanical seals.
Water should not be used as the rinsing fluid here with plan32. A cleaning fluid compatible with the media should be used as the flushing fluid. The flushing fluid of plan32 will indeed enter the pump chamber in the end. If a compatible flushing fluid is used, it will directly dissolve in the medium and flow out from the pump port without condensation. So I agree with what the third floor said, it may be plan62quench, which can use water, steam, nitrogen, etc. as flushing media to prevent crystallization and other undesirable phenomena from occurring. plan62 has a drain port to discharge the remaining liquid in the seal cavity. Please provide more detailed information.
The residual oil pump can be equipped with self-produced cold diesel oil, which is effective in cooling and lubrication. It is not appropriate to use water, and it is best to use softened water on the outside, otherwise scale will form. Just add an oil sealing line, a pressure gauge and a hand valve.
Have some questions: 1. The medium is high-temperature oil, and the flushing fluid in the P32 plan cannot be water. The flushing fluid must be pumped into the pump body. 2. The cooling water connection mentioned by the manufacturer may be the quenching solution P62 that does not enter the pump cavity. 3. I think the flushing solution here should be: P52 (if double-ended)+P32+P62