Automatic feed systems

At present, calcium and magnesium are estimated almost exclusively by atomic absorption (36). Present instrumentation permits the dilution of the specimen to approximately 1 - 100 for calcium and even higher for magnesium. For many instruments, the two elements are not read out simultaneously such as is practicable for sodium and potassium with the flame photometer. The lower limit of serum volime at present, for the practical assay for calciim and magnesiim in the laboratory of Neonatology, is approximately 10 ul The instruments are very readily automated, and it is not uncommon for results to be available at the rate of 240 per hour in the routine laboratory, where a typical atomic absorption instrument such as a Perkin-Elmer has been attached to an automatic feed system. 

Fed batch processes have a higher production per volume and often also a higher product concentration in the final fermentation broth. They need, however, continuous sterilization and an automatic feeding system. A fed batch process starts with the inoculum and a small part of the medium. More medium is added after the fermentation has reached a certain rate. The cells continue to grow until the reactor is full. The broth is removed from the reactor and the products are harvested. A small part of the fermentation broth is left in the reactor as the inoculum for the next batch. 

Batteries are continually fed into a 3.5 MVA electric arc furnace via an automatic feeding system during the melting process. Unlike the electric arc furnace steelmaking route, which can only facilitate batteries up to approximately 3% of the feed, the Valdi process loads batteries into a furnace which is void of steel except for a small heel. 

The sensitivity of this technique depends directly on the volume of the sample. Volumes of between 10 and 20 pi are very frequently used. The use of an automatic feed system is of considerable importance in this graphite tube AAS technique, having a crucial influence on the sample dosing on which precision and accuracy depend. Thus, not only the point in the graphite tube at which a sample is introduced is important, but also how the drop is applied to the tube wall. These factors can only be completely controlled by automation. A degree of reproducibility better than 1 % is achieved in this way. 

Providing an automatic feed system to reduce machine hazards... 

Corrosion monitoring can be used to provide operational infonnation. If corrosion can be controlled by maintaining a single variable (e.g., temperature, pH, chemical treatment, etc.) within limits previously determined, then that variable can be used to predict changes in corrosion patterns as the limits are exceeded in both a positive and negative direction. An extension of this technique is to use a monitored variable to control chemical addition directly through automatic feed systems. 

Tellus System. A system for bricklayers working inside steel converters. A horizontal working platform is hydraulically raised or lowered by a centra] column, around which is provided a spiral automatic feed system to deliver bricks to the bricklayers. 

Other machine features that offer protection include moveable barriers, automatic feed systems, presence-sensing devices, emergency stop control, hand control devices and mechanisms, such as pull-out devices, restraint devices, and two-hand control. Reduced speed control is used during setup, cleaning, and maintenance. Other safety mechanisms include antikickback devices, run controls, and foot controls. 

Alumina needed to be added throughout the process to replace the alumina consumed in the primary reaction. To achieve this, an automatic feeding system was designed to deliver regular amounts of alumina at defined intervals. 

Roller coating Raised surfaces can be painted without masking. Special effects like stripes. Roller applicator, either manual or automatic. Special paint feed system required for automatic work. Dryers... 

This basic operation utilises a two-bowl calender in horizontal or vertical configuration. The feed material, either in strip or pig form, is fed into one side of the nip and is squeezed by the bowls, thereby emerging as a sheet which is pulled from the bowl by some manual or mechanical means or supported by a liner cloth. Because of their versatility, three-bowl calenders are now more widely used for sheeting as well as other basic calendering operations. Thickness control is accomplished by use of the adjustable nips and may be further refined by automatic control systems using thickness sensors. It should be noted here that the force required in the nip to flatten the feed material causes deflection of the bowls, however slight. If some corrective steps are not taken, the product thickness will vary across the sheet, resulting in excessive variations of the product and possibly excessive use of expensive materials. In order to overcome these problems, three basic techniques are used to achieve uniform product thickness ... 

One of the most recent applications of the. VADS is in the US Navy s Phalanx ship-board antimissile system. Nine hundred-fifty discarding sabot depleted uranium rounds are carried in the feed system, and search and tracking radar are carried in a dome above the mounting. The gun is controlled automatically by the ship s fire-control computer, and a closed-loop spotting system measures the positons of target and projectile simultaneously to direct the stream of fire (at 3000 rds/minute) on to the target thruout the engagement (Ref 3)... 

Continuous dosing of inhibitor to the cooling system, with automatic feed adjustments, based on system demand and prescribed set points. 

The trash feed system consists of a high-efficiency cyclone that is equipped with a vacuum feeder that discharges into a screw conveyor. As the waste moved progressively through the lower chamber due to the additional charges of trash, it is reduced to ash and discharged from the incinerator by the automatic ash removal cylinder. 

A small community in the Midwestern US wants to fluoridate their potable water system. The community has a population of approximately 1700 and serves a large rural school with an equivalent school population of 2667. The community has two wells that are located 2 miles apart and are automatically controlled with pressure switches. Each well has a well house that contains bleach, polyphosphate, and soda ash storage and feed systems. Average daily production from both weUs is 0.210 MGD. The water has natural fluoride level of 0.13 mg/L. The optimal fluoride level for this community system is 0.8 mg/L. Determine (a) the feed rate and annual amount of sodium fluoride and (b) the feed rate and annual amount of fluorosiUcic acid solution, (c) Provide the advantages and disadvantage of each chemical feed system. 

Continuous chromium reduction treatment requires a tank for acidification and reduction with separate tanks for precipitation and sedimentation. The retention time in the reduction tank is dependent on the pH employed but should be at least four times the theoretical time for complete reduction. In cases where the chromium content of the wastewater varies markedly, equalization should be provided prior to the reduction tank to minimize fluctuations in the chemical feed system. Successful operation of a continuous chrome reduction process requires instrumentation and automatic control. Redox and pH control should also be provided. 

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