Oh hay there big boys…
So I am curious about folks recommendations and experiences with diffusion pumps. I am considering one for use with a pope 6" with that is to be used to pass degassed deterped feedstock (2nd unit on the way for voc’s terps and dogfart fish ass). I have two edwards 30’s available as roughing pumps.
I will be documenting everything the powers that be allow and will journal my upcoming failures here.
Also…I love this forum…makes me happy to see the collaborative spirit still kicking and to see those that contribute get some $$! Also, good to hear from some familiar characters from the IC forum.
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Hey, so there are many options. Alot of people undersiZe the diffusion pumps on their wipers… IMO. The key to a good run is consistent vac depth… the more consist… the more consistent the product… as well as the faster the pump recovers from a pressure bubble the more volume it can handle. So, you can get an air cooled edwards 50/60 for pretty cheap… or get into a liquid cooled diffstak 100 or 160… or a Varian variety. I use typically 300L/s varieties on my 8” wiper and can pass 10L an hour without vac depth destabilizing. Temp of jacket is always vac dependant… so if the vac remains stable… set temp accordingly and move on. I also have a diffstak 160 that does 700L/s, i prefer this for the stability, but finding a used one to rebuild on ebay is getting more and more rare… they also require about 3/4hp to maintain the cooling jacket.
In a diffusiob pump, exact voltage based on oil used is important… i found that based on dc-702 as the oil, my diffstak 160 rated at 240V actually likes 218V. I used an adjustable variac to set this.
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@anon42519203 well damn dude…so informative it causes cognitive dissonance, I cant recall who said it, but whoever said that this forum has the best signal to noise ratio was spot on.
One question…so you use the variac to modulate the voltage applied to the heat element given that the applied pump cooling and vac level are static? This is to maintain the proper oil temp/viscosity?
Also 3/4 HP to maintain the cooling jacket??? Holy shit…thats a spicy meatball
thanks so damn much for the feedback
The variac is meant to regulate the temperature of the heating coil, each oil needs a specific heat range to work correctly… too much or too little and it either wont come on or is unstable.
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