On Tue, 19 Oct 2010 02:27:21 +1300, "RussellMc" said:

> -  'Fridge  compressor - OK but messyish and  heavyish

These need to be oiled often and have filtered air to last very long,
but work pretty well. Especially since you don't need very high vacuum.

> - Suction side of various small pumps made for pressurising - fish tank /
> tyre inflator / electric breast pump (don't laugh) ...

I used an electric tire pump on a car for the vacuum brake booster. It
was an electric conversion vehicle so there was no source of vacuum. I
used a pressure switch so it could cycle on and off as needed. It only
lasted a year. Cheap stuff. Very noisy too.

> Commercial small units are often medical or specialist.=20

So this needs to be low-budget? Likely you can buy small DC vacuum pumps
for under $300 that do exactly what you want. That was the case when I
needed to replace the brake booster pump. Actually it was under $200 but
more than a decade ago.

Cheerful regards,

Bob

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