Originally Posted by
Petra
Oh, there are plenty that exist, it's just that most are rather overbuilt for our purposes (external gear pumps tend to work fine with water, internal gear pumps (like those used as oil pumps in cars) are usually meant for use with higher viscosity fluids). My guess would be that switching over from more traditional brass/bronze/steel construction to materials like UHMWPE and high molecular weight POM in an external gear pump would probably help with cost and lubricity/durability issues.