[Nhcoll-l] Vacuum jars and pumps

[Simon Moore]

Hi Tonya,

Just to respond to this. Dries is partly correct in that air bubbles - not generated by enthalpy (which I carefully explained) as Dries indicates but through the inevitable formation of them during rehydration, can slightly move internal organs around. I did also point out that if the vacuum pump was left running for too long, the fluid might boil in the reduced pressure, but as the specimen was in water, this would take a while longer as one should not run an oil-based vac pump with possible contamination from formalin or alcohol vapour.  

With all good wishes, Simon 

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian.

www.natural-history-conservation.com

> On 8 May 2025, at 12:21, Andries J. van Dam <ajvandam at ziggo.nl> wrote:
> 
> Dear Tonya,
>  I would be cautious to submit specimens to vacuum. It might aversively affect the morphology of the tissues (leak cell membranes / shrinkage). The formation of air bubbles is mostly related to the thermodynamic process of mixing when a specimen is subjected or transferred to a fluid with a different composition or concentration. Vacuum can also lead to boiling of the fluid once its vapor pressure is reached.  
>  Kind regards,
>  Dries
> --
> Andries J. van Dam (director)
> 
> Alcomon Company
> Leliestraat 54
> 2313BH Leiden
> Netherlands
> 
> Tel: +31615676299
> E-mail: ajvandam at alcomon.com
> Website: http://www.alcomon.com
>    Van: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> namens "Haff, Tonya (NCMI, Black Mountain)" <Tonya.Haff at csiro.au>
> Datum: woensdag 7 mei 2025 om 06:02
> Aan: "NHCOLL (nhcoll-l at mailman.yale.edu)" <nhcoll-l at mailman.yale.edu>
> Onderwerp: [Nhcoll-l] Vacuum jars and pumps
>  Hello all,
>  I am wondering if any of you have recommendations on vacuum jars, either in terms of styles, brands, or sizes? I’m being inspired by Simon Moore to think we would benefit from being able to remove air bubbles from wet specimens during the preparation process (or rehydration process when I get the time for that). If you also have recommendations for vacuum pumps I would also be very interested as well. Thoughts and caveats also always appreciated.
>  Thanks!
>  Tonya
>    ------------------------------------------------------------------------
> Dr Tonya Haff
> Senior Collection Manager
> Australian National Wildlife Collection
> National Research Collections Australia, CSIRO
> Canberra, ACT 2602 Australia
> +61(0)419569109
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