TABLE OF CONTENTS Pumps are very essential to move fluids around in all kinds of equipment. They occupy a dominant position in hydraulic machinery and there are large varieties of pumps. Basic materials used in pumps are indicated and justified in this chapter.
The pump is one of the earliest forms of machines, essentially unchallenged and thriving, similar to the bicycle. Pumps are used all over, in many diverse applications, to move fluids from one place to the other and they have undergone enormous improvements. They are produced in such a seemingly endless variety of sizes and types that it would take a separate book to survey those thoroughly. However, the main components and their functions can be defined with attendant basic materials selection methodology.
Pumps are classified into two major classes based on the way by which the power is transmitted to the pumped fluid. These are the positive displacement and the kinetic types. In the positive displacement pumps, energy is periodically added by the application of a force to one or more movable boundaries, which then displaces the confined fluid volume. This process results in direct discharge of the fluid for each stroke or revolution of the boundary. Kinetic pumps develop pressure by centrifugal force; the energy that is continuously transmitted to the fluid leads to radial, mixed, or axial flow.
The centrifugal pump consists of a set of rotating vanes or impellers enclosed within a housing or casing. In its simplest form, the centrifugal pump has two main...
