6” wiper seeking help for a client

Looking to seek advice on a wiper I’m having some issues with. I was contacted to help assist with getting a wiper operating after an installer had left my client with no insight on how to run their new equipment. They have a 6” steel china wiper dry ice cold trap with crvpro30 vac pump. I’m able to maintain around 60 micron vac depth while in my mains run. Currently running the feed pump at 30Hz wiper Motor at 250Hz and the gear pumps around 65-70Hz. What issues they are having is that it will make nice disty for a few minutes then switch to black crude. Any insight would be appreciated. Thank you.

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Does the vacuum level change at all when it goes from disty to crude?

Whats the temp on the body?

Thc or cbd?

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No change in vac. 172 on the body thc

Try slowing the basket rpms down and see if the same thing happens you could be getting splashing if crude is coming out the disty side


I’ll give that a shot in the morning. I noticed the wiper basket wasn’t centered to the body right before I left, so I have them getting that done overnight.

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By ‘switch to crude’ do you mean that crude comes out the distillate side?

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Yes I do.

You may have a warped body and you may never see good dist without heavy mods. Or maybe its simply unbalanced. Best of luck.


Just because I’m curious, how would a warped body lead to crude or at least very dark oil coming out the middle (distillate/condensate) pump? How would that work from a flow/physics standpoint? If anything I’d think that would mean more crude going out with the waste as it wouldn’t be getting full exposure to the outside diameter and thus not evaporating the good stuff out

My mind went to a shallow/unlevel weir at the bottom of the body between the outside (tails/waste) and middle (condensate) catch areas at the bottom of the body that allowed waste to spill over into the condensate area and get pumped out by the gear pump.

OP, if your customer slows down the feed pump dramatically do they still suffer from the same problem?
Also, what area are you in? Some of us like myself and @Dabatronicus have quite a bit of time spent fixing on Chinese wiped films

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I’ve tried running the wiper at various speeds all day today to try eliminating as many variables as I could today and I noticed no change between the various speed’s except for how much crude was coming from the residue side. I’m in OKC.

If the body is warped and the basket is flat there will be contact points and thus rocking. That rocking creates splatter and because pigments act the way they do, a little black spatter makes the rest of the crude black.


Were you running the same material over and over? I’m still learning on my wiper, but when I was testing, I was running the same material over and over and with vac issues kept having a lot of material sent to residue. Once I got the vac issues sorted, I kept running what was left of the residue to see what would happen, and it refused to distill at 200c. Curious if you’ve already wrung out your feed material.

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Is it a rolled film or a wiped film

Most wipers blades are not once piece but multiple smaller pieces and are not physically mounted to the basket itself, they sit loose inside a groove in the basket struts and the column wall itself. The centrifugal force of them spinning should press them into the wall even with minor warps in the side wall, some of them even have springs to help push them into the wall.

A roller is fully attached so a warped wall could have more effect

Out of the many dozens of wipers I’ve ran from every manufacturer out there. Have not once experienced a warped body. You’ll see a bent basket from time to time but that’s never been an insurmountable issue, lightly bend it back and it’s always been good to go.


You are definitely splashing the inner coil if you get nice gold at first. Are you doing a terp pass?m before the distillate pass?

If it’s the normal China wipers, those pump and wiper motor speed numbers are usually not in hz. If your at 30.00 on a 6in and only spinning 250, pumping too fast while spinning the wiper blades too slowly.

You should be at the max speed for the wipers which is typically either 400 or 466 on most China wipers.

If you need further consultation, please reach out on my instagram under the same name

You should be closer to 20-25 Feed pump speed on a 6in. That’s 5.4-6.75L/hour. Your current running it at 8.1L per hour which usually to fast for a 6in. (Model number (XXX-1S) with the Xs any random letters that represent the seller you bought it from.)

Number on screen x 4.5/1 gear ratio x 60 min/hour = Grams per hour

So 30 x 4.5 x 60 = 8100 Grams/hour

Once you’ve splashed the coils, it can take 1-2L of good distillate flowing to fully clean them off so even if you were hitting the right numbers after splashing, if you changed them quicker than every half hour, you likely never saw when you were at the right parameters

60micron is pretty damn high for a distillate pass but is doable. You want to be under 10 micron for the best product while also running the fastest it’ll go.


I use to run my 6 inch yhchem at the max feed rate which is around 9 kg an hour and never had problems with splashing

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There’s a ton of factors involved to diagnose an issue with a little over a single paragraph of info. What I recommended is where I would start. If OP would like to discuss this further, there’s options to do so, including posting more here and allowing everyone to crowdsource help. What’s pretty obvious is they are splashing the coils (Fouling is the proper industry term). I’d be extremely skeptical that it’s a warped column.

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Well fuck me. When our system is clean and hot, we were pulling around 70. When we start feeding, it shoots up to 180 on devoled material. It truly is an artform to get these fuckers to seal properly. I believe the leaks to be in the gear pumps, but have not pulled them to bench test yet. After rebuilding everything, we managed to hit ~20micron, but after ~20hrs of use, I believe our ptfe packing in the pumps have shot its wad.

Back in the lab this morning and had taken your recommendation on running the wiper motor at full speed and feed pump at 25. When doing that, the residue side was flowing like a geyser and the distillate side was hardly dripping. Vacuum depth was at about 100 microns when doing that. Slowed the feed pump down to around 3 and have been getting separation on both sides but flowing at a dribble. The color of the “distillate” is still very dark.

When I start the wiper for the day I get gold for a few minutes then it slowly turns to crude. Yea a terp strip is being performed.