I have just read a US Aviation Consumer article (can’t link to it – it’s a paid membership site) saying that most vac pump failures are caused by foreign object damage (FOD) from disintegrating vacuum hose internals, and that the hoses on the suction side of the pump should be replaced at intervals.
This should mean that on 30+ year old aircraft you should be getting through vac pumps at a fair rate!
I have also come across this new pump which instead of carbon vanes has composite aluminium+carbon ones
It costs more – over $600 I think. I have been using Tempest pumps and they go for 2 years before a significant performance drop is noticed during the 700rpm idle test.
The most interesting feature about that Sigma Tek pump is that it was designed to handle both positive and negative pressure loads.
Traditional dry pumps were not designed to drive the likes of pneumatic deice boots, although that’s what you find in most installations.
