There are many type of industrial pumps. Plunger pumps operate well on a contamination resistant fermentation like penicillin, but might be dangerous in other cases. Diaphram check-valve pumps have no sterility hazard and work reliably, but are quite expensive. Flexible liner pumps are satisfactory except for infrefquent liner failures and a tendency to leak if the pump stopped in the wrong position. Peristaltic pumps which squeeze tubing are good for special projects, but deterioration of the tubing during sterilization and from contact with the oil make them unsuitable for routine use.



The placing of a check valve on the plunger permits operation within an enclosed line with no sterility problems. Plunger motion is controlled from a solenoid, energized intermittently from a timer.