I'm putting together a high vacuum system which incorporates several bellows valves; all the surplus valves I've located are either manually operated or pneumatically controlled. Given that I need to be able to control the valves via my electronic control system, I've gone for the pneumatically operated valves. I'd like the system to be self contained and not reliant on a shop air supply, what suggestions do you have for a low volume pump that would be suitable for my requirements? Preferably something that can be found surplus if possible; the valves I'm using require 75 PSIg to operate.