Many industries worldwide use chemicals to perform a wide variety of tasks.Instrument Manifolds In fact, chemical consumers range from a typical homekeeper who purchases basic cleaning supplies to multi-national energy producers who require customized chemicals for the various stages of energy production. Historically, these larger chemical users have purchased chemicals in bulk. Thus, the chemical companies that supply these industries with chemicals have made the various chemical blends in large batches.

These larger chemical users often desire thousands of different blended chemicals. For example, oil refineries use custom-blended corrosion inhibitors in their processing plants to provide maximum corrosion protection for prolonging the life of the processing plants. Therefore, a chemical company may be required to stock hundreds of different intermediate chemicals, concentrates, or solvents, in order to produce these blended chemicals.

A typical device for blending chemicals includes a large vat capable of holding in excess of ten thousand pounds of chemicals. Large agitators are placed inside the vat to mix the chemicals that are added to the vat.Reducing Valves A plurality of lines feed chemicals into the vat. One end of a line is coupled to the vat, and the other end of the line is coupled to a container holding a chemical to be added to the mix. Pumps, coupled to the lines, draw the chemicals through the lines from the containers to the vat. The amount of chemicals added to the vat is controlled by mass flow meters, which are connected to the lines, or by determining the weight of the chemicals added to the vat.

Once the large batch of chemicals has been thoroughly mixed in the vat, a sample is removed and taken to a laboratory for testing. The testing may vary depending on the type of blended chemical desired. However, typical testing may include measuring the density of the blended chemical or taking the FTIR fingerprint of the chemical. If the blended chemical passes the test, it is packaged into appropriate containers and shipped to the customer. If not, the blended chemical must be further tested to determine the percentages of the individual chemicals which comprise the blended chemical.SAFETY VALVES Then, it must be determined how the blended chemical can be reworked in order to produce the desired blend. Finally, the proper amounts of additional chemicals must be added to the blend to achieve the desired blend. Once reworked, the blended chemical may be packaged and shipped to the customer.

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. 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. 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. 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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2011-12-29

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