A particular chemical blend
After a particular chemical blend has been packaged, i.e., removed from the mixing vat, the entire mixing device must be cleaned out. The clean out procedure typically includes flushing the lines and rinsing the vat. Next, the device must be set up in order to mix a different blend. This set up procedure may include connecting different lines to the vat, connecting the appropriate measuring devices to the lines or the vat, and connecting the lines to the appropriate chemical containers. After set up, the device charges chemicals into the mixing vat one at a time. Typically, the charging is performed manually with operators viewing the measuring devices and controlling the flow of chemicals through manually-operated valves. After the charging has been completed, the agitators mix the chemicals in the vat, and the inspection process is repeated, as set forth above.
The method and device set forth above suffer from many problems. First, the vat and agitators used to make large batches cannot make small batches. A small batch will not immerse the agitators, and, thus, the agitators are rendered ineffective. Second, the mass flow meters used to monitor the amount of chemical being charged through the line are expensive. Forged Steel Valves Furthermore, since the chemicals being charged may exhibit widely varying densities or viscosities, the flow meters tend to provide inaccurate information or to require frequent recalibration. Third, operators follow a written procedure to mix each batch.Bellow Seal Valve Thus, human error poses a continuous problem. Fourth, the required quality testing may add ten percent or more to the final cost of the blended chemical. Providing a laboratory and a staff of chemists requires significant overhead. Furthermore, the process often requires rework to prevent waste. Rework is not only expensive, but time consuming. Fifth, the fact that operators manually control the charging process inherently introduces undesirable inaccuracies.BALANCING VALVES Although a skilled operator may minimize these inaccuracies, the use of human judgment and manual operation remains a problem. Finally, the cleaning of the device wastes chemicals. Moreover, the chemicals removed from the device during its cleaning require disposal. This disposal is already quite expensive, and is becoming even more expensive with the increasing amount of government regulation.
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2012-01-06