ABSTRACT

There are dozens of variations on the 22 technologies presented in this chapter. Each one has a slight advantage in terms of some of the in nite combinations of range, tank shape, process materials, available power, pressure and temperature, and accuracy requirements. The purpose of this section is to assist the reader in narrowing the choices and focusing on the most appropriate technologies for a particular application. In selecting the level instrument, we should determine which factors are desirable and which are not. In practice, this is seldom carried out, and, frankly, there is a great tendency to reach for a d/p transmitter, if not a displacer, and live with whatever performance it produces. This is the cliché solution and, like so many clichés, it is, if not the wrong answer, often not the best.