Vacuum Pump

[eXcidium]

I was wondering here, wich kind of pump would be best:
I know most of you would say an Oil one, but I wonder if a
membrane one would do the job done (since it's 1/3 of the price, and it's still around $300)

The use for such device, would be, The Dr. Drool workup
And the Eugenol -> Safrole method


Specs :
Membrane vacuum & pressure pump
Pump rate litres / min     -> 1.08
Vacuum limit               -> -0,6 bar ² 440 mm Hg
PRESSURE Pump rate/min     -> 1,3
Maximum pressure bar       -> 1,3 bar
FEATURES

Small footprint, bench top
Quiet and vibration free.
Maximum working temperature: 40°C.

CONTROL PANEL

Mains power switch.
Vacuum gauge, scale 0 to -1 bar.
Pressure gauge, scale 0 to 2,5 bar.
Control for pressure/vacuum.
Vacuum in.
Pressure out. 



And also : here is the Oil pump i mentioned (wich costs a bit over $800)

FEATURES

Aspiration connection push fit.
High oil volume and forced lubrication.
Exhaust filter and ballast.
Shock absorber mounted.
Low noise level (
<62db)
Maximum working temperature 60°C.
Portable.

(now it has 2 models, I'll post both)

Model 1 :
Pump rate m³/h    -> 3,6
Vacuum limit mbar -> 0,1


Model 1 :
Pump rate m³/h    -> 1,8
Vacuum limit mbar -> 0,0006


Thanks everyone

[Osmium]

> Specs :
> Membrane vacuum & pressure pump
> Pump rate litres / min     -> 1.08
> Vacuum limit               -> -0,6 bar ² 440 mm Hg

That pump is absolutely useless. It's even too weak for filtrations.

[pyroflatus]

Model 1 :
Pump rate m³/h    -> 3,6
Vacuum limit mbar -> 0,1
This one would be adequate though.
Don't skimp on your pump. An acquaintence tried to get by with diaphragm pumps and ended up buying three pumps, none of which would allow vacuum distillation of temperature sensitive high boiling compounds. He spent more on inadequate pumps than he would have on a new dual rotary vane pump.

[eXcidium]

Damn!

Guess I'll have to spend those 800 after all...

Thx both of you  

[hest]

By one on ebay.

This is an ongoing thread.
With a diafrag you get's 5-10mmHg (bp for safrole 100°C)
With an oil pump you get 0.01-0.001 (bp for safrole 40°C)
The oilpump need a dryice freeztrap to last more than 6 month
The diafrag will last more than 6 month without a freeztrap.
Both pump will last a lifetime with a freeztrap and some love

[eXcidium]

Wondering.. what's a freezetrap?
and how should I care for it so that it lasts an age?
(this thread might be usefull for everyone)

This sums up to :
I REALLY have to buy it, and want it to last a long time
(perhaps even changing it's oil ever run or so, i have no idea on oil prices)

[chilly_willy]

[terbium]

The pump will draw down to > 29.5 in. Hg.
What is that oonverted into absolute pressure?

[Rhodium]

10-11 torr - see

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/pressure.html

[hest]

Wondering.. what's a freezetrap?

Freeztrap=cold trap

Post 32140 (missing)

(Prozac: "Vac Pump suggestion?", Chemicals & Equipment)

Post 24631 (missing)

(Antibody2: "Fridge Compressor role call", Chemicals & Equipment)

http://www.sigmaaldrich.com/Brands/Aldrich/Glassware_Catalog/Distillation__Traps/Cold_Traps_and_Vacuum_Traps.html

And one from ebay at 50$

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2588504685&category=26236

[eXcidium]

Thanks everyone.. really the hive is all about help...
now all i need is the best care for the vacuum pump
(like how many oil changes, and when, etc)

[Rhodium]

(like how many oil changes, and when, etc)

Whenever you suspect that the pump has inhaled water or corrosive (acidic/basic) fumes, or when it has inhaled low-boiling stuff so that the ultimate vacuum obtainable isn't as good as after a fresh oil change.

Rinsing the pump with flushing oil sometimes and not just change the oil is also worth the relatively low cost of it:

http://www.hyvac.com/tech_support/Flushing_The_Pump.htm

http://www.hyvac.com/PDFs/Literature/Oil%20Chems%20and%20Sealants/Flushing%20Oil/New%20Flushing%20Oil%20Spec.PDF

[eXcidium]

Thanks Chief bee and everyone for your kind help
now i must decide WICH one to buy, since it has to be an oil one