Vacuum devices for pressure molding, low-pressure molding, ingot molding, sand molding (metal casting); vacuum devices for injection molding (plastics); controls, valves, pneumatic installations and spare parts for such devices; transport devices for molten metal and thermoplastic materials (for injection molding), especially for the automatic feeding of foundry machines and injection machines (plastics); installations for assembling and casting and injection molding, in particular under pressure, controls, valves, pneumatic devices and parts for such machines and installations