For solid-liquid mixing under vacuum, what pump should be used?
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The company’s products include a type that is a mixture of solid and liquid; the proportion of solids is not high and it can vary, but the majority is liquid (methanol). It needs to be pumped under vacuum conditions before the pump (with a vacuum level of around 0.06 MPa). What kind of pump would be suitable for this purpose? Is a screw pump an option? I was thinking, is a plunger pump feasible? Dear friends from Sichuan, please give some recommendations; it would be great if you could also explain the reasons for your suggestions.
What is a solid? What size are its particles? Does it have hardness? If possible, please provide your contact information so I can help you choose the right option
If it’s just for pumping, both plunger pumps and screw pumps should work. However, from my experience, piston pumps suffer significant wear due to relatively hard solid particles. If those solid particles are lubricious substances such as stearic acid, then a piston pump can be used. Moreover, piston pumps generate significant vibration, which places higher requirements on the pipes. For screw pumps, single-screw pumps certainly won’t have any problems, while double-screw pumps are wasteful. The stator of a single-screw pump can be made of nitrile rubber, which is tolerant and does not swell in the presence of methanol; therefore, it doesn’t matter if the solids are hard ； That is, if the particles are hard, the stator will wear out after prolonged use, making it difficult to create a vacuum; at that point the stator needs to be replaced. Additionally, the vacuum pumping time using a single-screw pump should not be too long; liquid needs to be filled in during the first start-up, and both the screw and the stator must be coated with lubricant.
Thank you for your advice. I think if I were to buy one, a twin-screw pump would be a more reliable choice. The solids aren’t present from the start; they crystallize during the concentration process, so there’s basically no risk of very hard substances forming.
Double-screw pump? Then the original poster should remember to contact me when the time comes; hehe, I’m the one who deals with twin-screw systems. When using a twin-screw pump in such operating conditions, its performance is simply excessive. Metal bushings and spiral sleeves do not suffer from wear caused by crystal particles ； The gears are lubricated separately, and it’s no problem for them to run idly for ten to fifteen minutes or even an hour while under vacuum. The only spare part is the seal; it’s been in use for a year, and a bearing is replaced during maintenance – that’s all. Extremely easy to maintain——it’s just that the price is a few times higher than that of single-screw pumps, haha. If there are no particles involved, the cheapest gear pumps will suffice. For handling such precipitated crystals, gear pumps may produce more noise and vibration, but they are very inexpensive. If there are particles, a single-screw pump can also handle such conditions. It’s just that the rubber stator of the single-screw pump needs to be replaced more frequently, and it shouldn’t run idly for too long; overall, though, it’s capable of handling the operating conditions described by the original poster. If the poster’s unit has a relatively generous budget, they can consider a twin-screw pump—feel free to contact me then.