Electrostatic separators are commonly used to separate particulates which are entrained in an air or gas stream. For example, in the power generation industry fossil fuel, such as bituminous coal, is pulverized, burned, water in a boiler generates steam, and the steam drives steam turbines which in turn drive generators to produce electricity. The ash resulting from the burnt fossil fuel is blown into electrostatic separators which may include a series of housings defining chambers in which electrostatic collecting plates are suspended and/or supported in so-called "fields" and "bays." Thousands of such collecting plates are located in a typical chamber and these collecting plates must be in precise parallel spaced relationship to each other with planes passing therethrough being generally parallel to the air flow through the chambers. As the particulate-entrained air passes between the collection plates, the particulate material is separated therefrom electrostatically in a conventional manner, drops to the bottom of the housing and is discharged through conventional hoppers with the clean air leaving the housing through an associated discharge opening for further treatment, should such be necessary, as might be dictated by emission criteria of state, municipal or federal agencies, such as the Environmental Protection Agency (EPA).
Typically, a single collecting plate ranges in height between approximately 40-48 feet and a typical width would be approximately 11/4 feet. Typically, each collecting plate might weigh between 173-207 pounds and normally such plates are roll formed and are easily bent and/or twisted. Thus, extreme care must be exercised at all times in handling the collecting plates, including during installation, maintenance, etc.
However, collecting plates are subject to normal distortion over time and the desired parallelism between adjacent collecting plates can lessen to a point at which one or more collecting plates can become extremely inefficient and/or inoperative. A typical collecting plate might over time develop undesired longitudinal camber, longitudinal bow, transverse twist, transverse bow, or the like. Longitudinal camber in a collecting plate of approximately 40-48 feet must be in the range of plus or minus 3/16". Longitudinal bow of a like dimensioned collecting plate must not exceed 1/16" in 3 feet of collecting plate length. The total transverse twist of the collecting plate must be no more than 3/4", whereas the transverse bow must be between plus or minus 1/8". Thus, tolerances of collecting plates must be exactingly maintained over time to likewise maintain the efficiency of the associated electrostatic separation process. Heretofore, distorted, bent, twisted, etc. collecting plates had to be removed and replaced by new collecting plates or those found unacceptable tolerance-wise or might otherwise be inoperative were necessarily removed, repaired and replaced, all at appreciable costs, including, of course, downtime of the electrostatic separator or at least a portion thereof (bay and/or field) from which particular collecting plates are being repaired and/or replaced.