Vacuum pump oil 1

[vasicmilos]

Dear all we have a vacuum coating machine in our pet food production line. Process is such that there is some moisture and very fine dust sucked to a pump. This polutes the oil very much. If this is already inevitable I was thinking of using cheaper compressor Mobil rarus 427 oil instead of Busch VM100 mineral oil. I would be able to change oil more frequently because of the price. Does anyone have experience with this

 

[vasicmilos]

Property Mobil rarus 427 /VM 100
Grade ISO 100 ISO100
Viscosity limit  100 /100
Density @ 15 C, kg/l, ASTM D1298 0.879 /0,891
Flash Point, Cleveland Open Cup, °C, ASTM D92 264/ 264
Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 11.4 / 11,1
Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 104.6 / 100
Viscosity Index, ASTM D227 100/ 96

 

[EdStainless]

First, look at adding a filter box in the intake line.
Secondly, consider adding a recirculating filter system to the pump.
By continuously filtering a small amount of the oil you can keep the system cleaner.
Third, don't change to a non-food safe oil.
You will have back streaming of oil from the pump into your product.
This always happens even if it isn't highly visible.

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P.E. Metallurgy, consulting work welcomed

 

[vasicmilos]

There are inlet filters first the CamMet Metal Filter SS then standard BUSCH paper air inlet filter.
I am not sure how we can ad recirculating oil filter however what we can do is to once in a month or two when vacuum is not used take out oil, filter it and put it back.
My question was more about specifications of compressor and vacuum pump oils and possibility to use compressor oil in vacuum pump. Because compressor oil is 5 times than vacuum cheaper I could change it more often

 

[pierreick]

Hi,
Wrong design! Those dry vacuum pumps are designed for clean stream (based on my experience). Ejector or liquid ring pump are more suitable for your application. Did you contact Busch for support, they should recommend a filtration unit to be added on the inlet of the pump?
Your proposal to replace mineral oil, suitable for pet food, with a cheaper one, is not acceptable and will cost $$$ to your company if discovered by any administration.
My view.
Pierre

 

[Compositepro]

Vacuum pump oil is designed to be very low vapor pressure in addition to being a lubricant. This is very important in achieving vacuum less than one Torr. If 10 Torr is acceptable, then you can get away with using hydraulic fluid instead. It will probably void any warrantee, though. I have used hydraulic fluid in a Stokes pump for about 10 years, and the pump performance has not degraded with time. If you are dealing with moisture, a ballast valve feature is very important. This bleeds air into the pumping chamber at the tail end of the compression stroke to keep water from condensing into the oil.

 

[EdStainless]

We continuously filtered vacuum pump oil any time the pump was running.
It was a small unit with a pump and two filters.
Oil came from the drain and was returned to the fill port.
It added 4L to the total oil capacity and only circulated about 0.5L/hr

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P.E. Metallurgy, consulting work welcomed

 

[vasicmilos]

Thanks everyone for help and advices!
So this pump is 15kw and pumping speed 630m3/h, for our process minimum vacuum level is 350mbar. Yesterday we put in the compressor oil, first impression is all is the same. Time to reach vacuum level inside the coating chamber has decreased a little because I changed inlet filter. There is one sort of settling tank inside of the housing and it was completely full with substance like pudding that is I think dust from the product mixed with bad oil. We cleaned it.
At the moment we dont have installed gas ballast valve I will check the possibility to add it, as I saw on couple of places it is necessary for applications where humidity is present.

 

[EdStainless]

How are you preventing the oil vapor back streaming into your product?

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P.E. Metallurgy, consulting work welcomed

 

[vasicmilos]

There is no return valve on the entry point to vacuum pump.

https://www.youtube.com/watch?v=l__XV6ERTZk

 

[EdStainless]

That does nothing to prevent vapor back streaming.
We had mechanical filters and cold boxes and we still had to clean oil residue out of our vacuum chamber periodically.

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P.E. Metallurgy, consulting work welcomed

 

[vasicmilos]

I have to say that I never thought in this way and I have been working in many companies using vacum for packagıng of snacks. So far never have I hear the complain or did anybody from auditors asked how do we control vacuum pump oil getting back into the product! Frankly I am not sure that that is even possible for example on this machine that I am now using vacuum pump is around 10 m away from the machine in between there are two filters I really don't understand how vapor from oil could get all the way back into the vacuum chamber, if understood your remark correctly

 

[EdStainless]

It is called diffusion.
And the force of diffusion is stronger than any vacuum.
If people in your business don't care, then I guess that you are free.
But you do need to ask what would happen if you got a slug of oil back into the system as the result of a failure.

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P.E. Metallurgy, consulting work welcomed

 

[stun]

Hello, wondering any update for the substitution? Thanks

 

[vasicmilos]

Hello so far I we haven't experienced any problems with compressor oil. However I must say that since we changed to compressor oil we had produced much less product that need vacuum coating so take it with reserve. Lets say that after 250 working hours no change in performance is noticed.