Vacuum Pump Gas Ballast Operation

This video explains the use of a gas ballast on a rotary vane vacuum pump to remove volatiles from the oil used for sealing the pump.

[@rex-up9ln]

My organic synthesis lab (newly setup) bought two edwards rv3. We used one for rotovap, another for drying samples. Nobody told us we must use a cold trap. Both pumps got damaged within a month. Technician removed about 200 grams of what appeared to be gunk along with some nicely crystallized stuff from the insides of one pump.

[@GnosisMan50]

thank you for sharing your video. I have a question: When you have the ballast set to zero and you let it run to remove volatiles, how long should you let it run at zero and what is the difference when running the pump at 1 or 2?

[@PopeScientificInc]

When the ballast is set at zero there is no air introduced, a small amount is introduced when set to one and more when set to two. We recommend setting the ballast to two for at least 30 minutes after processing, but a longer amount of time is preferable. When the pump is set to zero, it will not be optimized for removing volatiles, but instead will pull the deepest possible vacuum. If very strong vacuum is not required, the gas ballast can be left open (set to one or two) while processing.

[@RajasekarRamu-pq7bf]

Smoke coming continued any issue..pls suggestions?

[@dimkoz28]

I have a Pfeiffer duo 10. Using it for freeze drying. I have option 0 and 1. When using this to make food grade product, which option do i want? Thanks in advance!

[@albertrios5168]

We are using a Pfeiffer Duo 3 for a Scanning Electron Microscope. we only look at solid items. Should I keep the ballast open at 1 or closed? (ours shows 0 or 1). Or should I have it open until a specific vacuum range is achieved and then close it? Thank you.

[@PopeScientificInc]

Hello - For most rotary vane type vacuum pumps it is best to open the gas ballast prior to shutting down the pump to ensure any volatiles are removed from the pump, if this is done and the pump is being used on dry materials, you could likely start the pump with the gas ballast closed. However, it would be best to reach out to Pfieffer directly to get their expert opinion on use of your pump.

[@disgraziato5473]

Hello - good video. I have an Edwards D40B vacuum pump. We exhaust our ballast directly to a fume hood to reduce the odour. The distance is long, and I think residual off gas is coming back into the oil and decreasing its life. Do you have any suggestions as to how I can prevent odour and at the same time increase the longevity of our oil? I was thinking of using a trap of some sort?

[@PopeScientificInc]

Hi, Thank you for the compliment! The first thing to check is whether or not you have any suction (even slight) at the outlet of the vacuum pump / inlet of your line that goes to the fume hood. If you create back pressure at the pump outlet, this can reduce the ultimate vacuum achieved by the pump. If this doesn’t clear things up, feel free to give us a call and we will try and provide some more clarity!

[@zachreyhelmberger894]

Oh wonderful! So I do not have to have a source of compressed gas to inject into the gas ballast port?! I have a HarvestRight freeze dryer and on the side of the pump, there is a knurled knob that says "gas ballast ON OFF" in the documentation, it is called part number 46 "knob". So if I loosen that knob, it looks like it can come completely off, which I assume is not a good thing. So from finger tight, I should rotate it counter-clockwise 360 degrees or so, right?

[@PopeScientificInc]

It may depend on your model of vacuum pump. We utilize Edwards E2M18’s that have a knob for the gas ballast. This takes approximately 6 full turns before it is fully open, at which point you start to feel some resistance to opening. If you are using a different pump, a good sign that the ballast is open is that the ultimate vacuum in your system has decreased. We would recommend reaching out directly to the vacuum pump manufacturer if further clarification is required.

[@jaydouglas5847]

Hi Zach, What did you learn about using the gas ballast knob . Just got my harvestright unit tonight and the standard oil based pump manual says nothing about this valve, its not even shown in the booklet. Any advice/help would be greatly appreciated.

[@arthamnews6779]

200lpm???

[@arthamnews6779]

Lpm???