IV. PUMP APPLICATIONS
A. Types of Reciprocating Pumps
1. Single acting plunger pumps fill on the reverse stroke and exhaust on the forward stroke. The liquid end is sealed from the atmosphere by packing around the plunger. This type of pump is commonly called an "outside packed" pump. WGI manufacturers these pumps with either one, two, three, or five plungers/cylinders. This type of pump is horizontally operating.
2. Single acting piston pumps exhaust only during the forward stroke of the piston, that is, during one half of the revolution.
3. Double acting piston pumps fill and exhaust on the same stroke, one side of the piston facing the end of the cylinder being filled and the other side of the piston exhausting the other end of the same cylinder. This type of pump is commonly called an "inside packed" pump where the "packing" is a series rings or a set of rubbers which stop leakage from one side of the piston to the other. The piston rod diameter is relatively small compared to the diameter of the piston and is easily packed to avoid leakage. This type of pump is also horizontally operating.
