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Author: Subject: Buchi rotovap - slipping belt drive
PumpkinDad
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[*] posted on 23-1-2016 at 09:12
Buchi rotovap - slipping belt drive


Hi everyone,

I have an old Buchi R-124 Rotovap. After about an hour or so of operation, the belt drive begins to slip. The evaporation flask stops suddenly, then rotation starts again in about a second.

I'm wondering what might be the cause of this and how I could go about fixing it?

Thanks,
PD
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Zephyr
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[*] posted on 23-1-2016 at 13:17


Very hard to diagnose without any photos, I have some experience with rotovaps, and if I could have a look I could probably find you a fix.



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XeonTheMGPony
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[*] posted on 23-1-2016 at 13:32


Well with any belt drives you can try cleaning it all with isopropyle alcohol that the belt rides on, All so belt deflection should be less then a 1/4 inch.

Check the rotating berrings, ensure they ride smooth.

It is a simple mechanical system, so treat the common belt issues that can effect such a system.

If the belt deflection is out of spec, you can use a belt dressing spry but order a new belt now as yours is ready to go (Providing there is no option to adjust tension)

But given the nature of the device I'd look at the rotating barring first.

http://www.ebay.com/itm/Buchi-R-124-Rotavapor-Evaporator-PAR... < For parts if needed.

[Edited on 23-1-2016 by XeonTheMGPony]
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PumpkinDad
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[*] posted on 30-1-2016 at 13:13


Hi everyone,

Sorry for the delayed response. I got called away on business.

I couldn't figure out how to open up the drive unit on the R-124. There are two large screws but I can't get them to loosen up for the life of me.

I was contemplating forcing it, but then I saw an old R-124 unit for parts for sale on eBay and got it for a great price ($80). I swapped out the drive unit and while I still have to do a vacuum test, it rotates perfectly.

PD
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XeonTheMGPony
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[*] posted on 30-1-2016 at 13:19


Do not toss the drive, practice working on it.
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PumpkinDad
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[*] posted on 30-1-2016 at 15:17


Absolutely... I would never toss a working part. Only problem is I can't figure out how to get it open. The two screws seem like an obvious way in, but I can't get them to loosen up for the life of me.
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[*] posted on 30-1-2016 at 15:20


Can you be sure the source of the rotation stopping is the drive slipping? Many times removal of the rotating tube from its assembly and cleaning it will get a rotovap that stopped rotating back in working order.
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PumpkinDad
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[*] posted on 31-1-2016 at 13:59


Oh, I didn't know that. Well, I already replaced the drive so if the problem returns, I will take clean the vapor duct and see if that fixes it. Thanks for the tip!

PD
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youtubechem
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[*] posted on 27-1-2017 at 19:50
Did you ever find out how to get in?


I have bought the 111 model and it turns intermittently the fan on the back of the motor stops turning as well.. I was told to grease the bearings but can't find my way into the thing.
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Corrosive Joeseph
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[*] posted on 27-1-2017 at 20:29


Quote: Originally posted by youtubechem  
I have bought the 111 model and it turns intermittently the fan on the back of the motor stops turning as well.. I was told to grease the bearings but can't find my way into the thing.


We had this issue lately on an old RE-111 l found.......... it would stop turning intermittently, but only on low speeds.........

We took the motor off for a look, and not wanting to dog the bejaysus out of it, couldn't get the bearing out..............

So we managed to squirt quite a bit of 3-in-1 (machine) oil in the motor shaft hole, on to the bearing race, whilst turning it by hand......... This was followed by a good soaking of penetrating fluid (WD-40), in the hope that the WD would slightly thin the machine oil and drive it in there, all the while, turning the bearing by hand back and forth (and round and round), hoping to work it in...............

We then let all the excess oil drip dry, and wiped down the casing with a dry cloth to clean it up. We put the whole thing back together, fired it up and.............

Bingo, no more sticky bearing.............. Looks like this old Rotovap is gonna live a while longer..............

Hope this helps...................


/CJ




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youtubechem
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[*] posted on 2-2-2017 at 12:47
Which screws?


How do you gain access to the bearings?
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youtubechem
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[*] posted on 6-2-2017 at 11:47
My bad


After purchasing another faulty RE 111 from ebay I found the courage to dissect the newer one, which seemed to be more defunct. I was able to get the motor and screw gear apart and noted it was funky inside and the motor bearings were likely shot as well. Should I continue the tear down and replace the motor bearings or are they "not user serviceable"?
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Corrosive Joeseph
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[*] posted on 27-2-2017 at 03:46


Buchi Rotavapor RE-111, RE-121 and EL-131 Manual..................

Attachment: Buchi Rotavapor RE-111, RE-121 and EL131 Manual.pdf (2.7MB)
This file has been downloaded 366 times


/CJ




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