I have the F42400-4011 35 liter clear cabinet desiccator that I just purchased. I got it to pull the vacuum I need using an inline vacuum pump that has a free air capacity of 3.2. My dilemma is that it takes more than a minute to evacuate the chamber. Is this just pretty much the standard time or could I improve on this with a larger capacity vacuum pump?
Thank you, Melissa E.
Lab Guy here! On average, a well-sealed desiccator with an adequate vacuum pump should be at full vacuum in about 10 seconds or less. Your reported time of 1+ minutes is waayyy too long, so, let me ask you:
After evacuating the chamber and shutting off the pump, how long is the vacuum retained in the chamber?
If the vacuum pressure is released quickly (minutes to hours) then the problem is probably a faulty gasket or valve in the desiccator cabinet. The good news, gaskets are easily replaced.
If however the vacuum pressure is retained for upwards of 3 days, then an under-powered vacuum pump is the culprit and I would recommend getting a vacuum pump that is aligned with the size of your desiccator chamber. There is also a chance that if you are using an under-powered pump you also will never achieve a full vacuum.
Thanks for writing to Lab Guy, and please feel free to write back if I can help in any other way…
Yours in science-