For a refined fuel pump at 320 degrees Celsius, what should be the seal selection and flushing method?
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Among the devices I maintain is a high-temperature centrifugal pump with dual supports. Model: 300AYS190I – The seal needs to be replaced every six months; it is of the bellows type, model YH604-52, manufactured by Xi’an Yonghua. Upon removal, scaling was found and the bellows had lost their elasticity. During normal operation, the temperature of the sealing gland (Gran) is around 110 degrees Celsius. The ideal temperature is 50 to 60 degrees Celsius. It is now planned to switch to external flushing, by introducing room-temperature diesel (43 degrees Celsius) from outside the device, passing it through a filter, and then using it to flush the seal. (The previous coil coolers had very poor cooling performance; steam cooling was also tried, but it wasn’t effective either, and the bearing housings were prone to getting flooded with water.) Dear sea friends, do you have any better suggestions or ideas?
The bellows from Xi’an Yonghua are not very reliable; it is recommended to use DBM or Dandong Bellows Sealing. This factory was later split into three separate factories: DBM, Yizheng, and one more whose name I can’t remember. The quality is the same, and the bellows can be interchanged.
Normally, as you said, it’s 110, and the surface temperature won’t reach 200 either; the temperature is quite acceptable. Try changing to a different sealing manufacturer first; if that doesn’t work, then change to external flushing. The external flushing cost is high. As you said, there is a heat exchanger, but it’s not clear whether there is a pump-effect ring for sealing; in other words, it’s unclear whether scheme 21 or scheme 23 is being used. Also, which company makes the pump? Are both the sealing assistance system and the seals from Yonghua? If you contact the manufacturer, they will resolve it for you.