Cooling automation

In high-performance installations, when a tank reaches a maximum preset temperature, a pumping-over operation is automatically performed to homogenize the temperature. If the temperature remains too high after this first operation, the tank is cooled. Automated temperature control systems have been designed that regulate the temperature throughout the entire fermentation process. 

Filtration and water-knockout systems are used to clean up the gas before it enters a compressor. Cooling systems are sometimes required to maintain compressor discharge temperatures below 54°C to avoid damage to the pipeline s protective coatings. Automated compressor stations are typically staffed by maintenance and repair personnel eight hours per day, five days per week. Other stations are staffed on a 24-hour basis because personnel must start, stop, and regulate compressors in response to orders from the dispatch office. 

Cool on-column injection is used for trace analysis. Ah. of the sample is introduced without vaporization by inserting the needle of the syringe at a place where the column has been previously stripped of hquid phase. The injection temperature must be at or below the boiling point of the solvent carrying the sample. Injection must be rapid and no more than a very few, usuahy no more than two, microliters may be injected. Cool on-column injection is the most accurate and reproducible injection technique for capihary chromatography, but it is the most difficult to automate. 

For many bonding applications a variety of adhesives can perform adequately. Hot melt adhesives are normally chosen where process speed is critical. Since hot melts have no carrier vehicle (solvent or water), and thicken rapidly as they cool, they are limited in their ability to (1) penetrate low porosity substrates or wet out very rough surfaces (2) cut through or imbibe surface contaminants and (3) wet out high thermal conductivity substrates (e.g. metals). Nonetheless, hot melts are increasingly the adhesive of choice in automated production environments because of their fast set speed. 

The crystallization kinetics defines the open time of the bond. For automated industrial processes, a fast crystallizing backbone, such as hexamethylene adipate, is often highly desirable. Once the bond line cools, crystallization can occur in less than 2 min. Thus, minimal time is needed to hold or clamp the substrates until fixturing strength is achieved. For specialty or non-automated processes, the PUD backbone might be based on a polyester polyol with slow crystallization kinetics. This gives the adhesive end user additional open time, after the adhesive has been activated, in which to make the bond. The crystallization kinetics for various waterborne dispersions were determined by Dormish and Witowski by following the Shore hardness. Open times of up to 40 min were measured [60]. 

There are a surprising number of computer-con-trolled systems in homes today, all acting independently to control heating, cooling, security, lighting, appliances, entertainment equipment and even coffee makers. Houses of the future will integrate all of these computerized functions into centralized home automation systems that will help optimize energy... 

Figure 14-2A. Alternating current (AC) induction motor cross-sectional view of 220/440V, 3-phase, 60-cycle, totally enclosed fan-cooled standard motor. (Used by permission Reliance Electric Co., Div. Rockwell Automation.)...

In situ XRD stndies of thermally and chemically induced transformations were monitored with a totally automated diffractometer-micrometer system (9). Samples were thermally ramped in 5°C increments from 30 to 160°C, maintained at 160°C for 0.5 hr, and then cooled in 5°C increments to 30°C under 500 torr hydrogen. 20 scans were obtained after each temperatnre increment. The individnal scans conld be stacked to show the temperature evolution of the stracture. 

Stripping of hazardous substances Mercury switches and other components containing particularly hazardous substances must be removed CFCs are recovered from the cooling circuit and PU foam with special equipment and appliances with varying degrees of automation ammonia is dissolved in water and separate disposal of waste oil (from compressors). 

Kim J-K and Smith R (2003) Automated Retrofit Design of Cooling Water Systems, AIChE J, 49 1712. 

Any problems in the setup, startup, and operation of the CBMS also were recorded in the course of the field tests. These observations are important to improving the system before it goes into production. The field tests revealed three problems. The protective screens over electronics cooling air inlets and outlets on the CBMS II housing were damaged by operator activities in the vehicles and required reinforcement. The ground probe head, which protrudes outside the vehicle hull, required more power to maintain the correct temperature under colder or wetter weather conditions. Finally the automated mass and frequency calibration procedure was not reliable in the field and required modification. These problems have been corrected and are being incorporated in the LRIP units. 

Eberlein and Kattner [194] described an automated method for the determination of orthophosphate and total dissolved phosphorus in the marine environment. Separate aliquots of filtered seawater samples were used for the determination orthophosphate and total dissolved phosphorus in the concentration range 0.01-5 xg/l phosphorus. The digestion mixture for total dissolved phosphorus consisted of sodium hydroxide (1.5 g), potassium peroxidisulfate (5 g) and boric acid (3 g) dissolved in doubly distilled water (100 ml). Seawater samples (50 ml) were mixed with the digestion reagent, heated under pressure at 115-120 °C for 2 h, cooled, and stored before determination in the autoanalyser system. For total phosphorus, extra ascorbic acid was added to the aerosol water of the autoanalyser manifold before the reagents used for the molybdenum blue reaction were added. For measurement of orthophosphate, a phosphate working reagent composed of sulfuric acid, ammonium molyb-... 

Two potential disadvantages of temperature programming are the inevitable delay between consecutive chromatographic runs whilst the oven is cooled down and a stable starting temperature re-established, and the possible decomposition of thermally-labile compounds at the higher temperatures. Computer-controlled systems have improved the reproducibility of temperature programming, and automated forced cooling of the oven... 

Light non-methane hydrocarbons (NMHCs) were measured using an automated GC-FID system with large volume sample collection onto a Peltier cooled carbon sieve trap followed by on-line thermal desorption, and separation on an aluminium oxide PLOT capillary column. The system deployed at Cape Grim has been described in more detail in a previous paper (Lewis et al., 2001). 

Cool on-column Entire sample enters column Effective trace (ppb) analysis Little-no sample degradation Entire sample enters column Dirty samples problematic Automated operation not routine special syringe... 

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