Carrier equipment

Figure 23.9(b) Typical layout of a line coupling device and carrier equipment (PLCC) showing phase-to-phase coupling... 

Higli-riet iieney disimbailees are not transfeired to tlie carrier equipment through the coupling equipmenl. 

In flex-link assembly systems, the workpieces are usually transported by workpiece carriers equipped with workpiece-specific lifting and holding devices. The transfer movement usually results from the friction between the workpiece carrier and the transfer equipment (belt, conveyor, plastic link chain, etc.). The transfer device moves continuously. However, the workpiece carriers are stopped during the execution of the assembly processes. In the assembly station, each of the workpiece carriers is stopped and indexed. If high assembly forces are required, the workpiece carriers must be lifted from the transfer device. 

When we want to use this time to modeling of delivery process, we should check this from the point of view a efficiency a technical and organizational conditions of carrier equipment. 

Today, a great variety of OBS exist for different scientific purposes short-period instruments mainly for active-source experiments, broadband seismometers for passive earthquake recording, small-sized OBS for short-term deployments, and larger platforms with independent operating times of 1 year or more. Technology developed rapidly since the first OBS deployments, but the principle remains the same an instrument carrier, equipped with one or more sensors, a data logger with batteries, and a release unit, is weighted with some ballast anchor and sinks freely down to the... 

Sprays are the most common means of insecticide appHcation and generally involve the use of water as the principal carrier, although volatile oils sometimes are used. With the older inorganic insecticides, suspensions in water were used at dilutions of 0.1 ndash 0.2%. The development of the more effective organic insecticides has allowed the widespread use of concentrate sprays in which the toxicant is contained at 10 ndash 98% and the amount of carrier to be appHed is enormously reduced. The use of concentrate or ultralow volume sprays has brought about a revolution in spray equipment away... 

Milk may be a carrier of diseases from animals or from other sources to humans. To avoid contamination before pasteurization, healthy animals should be separated from sick animals or those with infected udders. The animals should be clean, kept in clean housing with clean air, and handled by workers and equipment under strictly sanitary conditions. Post-pasteurization contamination can occur as a result of improper handling, due to exposure to contaminated air, improperly sanitized equipment, or an infected worker. 

Ammonia is usually transported for long distances by barge, pipeline, and rail, and for short distances by tmck Eactors that govern the type of carrier used in anhydrous ammonia transportation systems are distance, location of plant site in relation to consuming area, availabihty of transportation equipment, and relative cost of available carriers. Typical costs (83) of pipeline, barge, and rail modes for long distance transport are 0.0153, 0.0161, and 0.0215 per ton per kilometer, respectively, for distances of about 1600 km. Short distance tmck transportation costs (83) are much higher. Costs are typically 0.0365/(t km) for distances on the order of 160 km. 

Liquid toners are suspensions of toner particles in a fluid carrier. The carrier is typically a hydrocarbon. Dielectric, chemical, and mechanical properties of the Hquid must be compatible with the photoreceptor, the suspended toner particles, and the materials of the development equipment. Liquid toners are capable of producing higher resolution than dry toners because of the smaller (3—5 -lm) particle size achievable. Development of the latent image occurs as it passes through a bath of toner and the charged particles are attracted to the oppositely charged surface. 

The extent of purification depends on the use requirements. Generally, either intense aqueous extractive distillation, or post-treatment by fixed-bed absorption (qv) using activated carbon, molecular sieves (qv), and certain metals on carriers, is employed to improve odor and to remove minor impurities. Essence grade is produced by final distillation in nonferrous, eg, copper, equipment (66). 

In conventional chemical pulping systems, micronized talc is used for pitch control. The mechanism is not well understood, but talc does adsorb on the pitch and detackify it, preventing it from agglomerating and attaching on equipment. In de-inking talc is used both to enhance ink removal in conventional screening/centrifugation methods and as a carrier in flotation systems. 

In general, DOT safety regulations fall into two categories. The first pertains to qualifications and hours of service of carrier employees and the safety of transport operations and equipment. The second, of special concern to the chemical industry, pertains to the transportation of hazardous materials and related commodities. 

The acid may be shipped in tank cars, tank tmcks, iso-tainers or dmms via common carrier (40). The shipping ha2ard class is Corrosive Material, the DOT labels and placards required are Corrosive and Poison. The UN number is 1754. When iron content and color are not of concern, the acid may be stored and shipped in steel equipment. The iron content is generally 25—50 ppm and the color is pale yellow to amber. 

There are many chemicals, by lowering suitable as carriers. Their bp is one of the principal criteria in selection. If bp is too low, the compound will evaporate from the dyebath at dyeing temperatures, and will be lost before it is effective in its role as a carrier. It may also steam distill (condense on the cooler parts of the equipment) and cause drips that will spot the fabric. On the other hand, if the bp is too high, the compound cannot be removed from the fabric under normal plant drying conditions and will affect lightfastness of finished goods, leave residual odor, and possibly cause skin irritation to the wearer. 

The preemulsified carriers contain water. These products usually require homogenization through colloidal mills or similar equipment to reduce the particle size and ultimately stabilize the product. The preemulsified as well as the clear self-emulsifying products require the use of a solvent when the carrier-active material is a soHd. 

The formulation of a carrier depends on four considerations (/) the carrier-active chemical compound (2) the emulsifier (J) special additives and (4) environmental concerns. Additional parameters to be considered in the formulation of a carrier product with satisfactory and repeatable performance arise from the equipment in which the dyeing operation is to be carried out. The choice of equipment is usually dictated by the form in which the fiber substrate is to be processed, eg, loose fiber, staple, continuous or texturized filament, woven or knot fabric, yam on packages or in skeins (see Textiles). 

The carrier-active chemical is selected according to its effectiveness at various temperatures. Members of the phenoHc group (Table 2), considered to be stronger carriers, are employed for formulations to be used in open equipment at the boil. Weaker carriers, such as the members of the aromatic ester group, are utilized generally for high temperature dyeing. 

A carrier is selected by the dyer according to various criteria. The type of equipment and conditions under which it is to be used have already been mentioned. Other considerations include color yield, dye migration, and product and emulsion stabiUty. 

Dyeing procedures vary according to the fiber content of the textile material and the equipment to be used. Examples of basic carrier dyeing procedures are as follows. 

Polyester (Textured or Filament) Dyed Under Pressure. The dyebath (50°C) is set with water conditioning chemicals as required, acetic acid to ca 5 pH, properly prepared disperse dyes, and 1—3 g carrier/L. The bath is mn for 10 minutes, then the temperature is raised at 2°C/min to 88°C and the equipment is sealed. Temperature is raised at l°C/min to 130°C, and the maximum temperature held for 1/2—1 h according to the fabric and depth of shade required. Cooling to 82°C is done at 1—2°C/min, the machine is depressurized, and the color sampled. The shade is corrected if needed. Slow cooling avoids shocking and setting creases into the fabric. Afterscour is done as needed. 

Most carrier-active compounds ate based on aromatic chemicals with characteristic odor. An exception is the phthalate esters, which are often preferred when ambient odor is objectionable or residual odor on the fabric caimot be tolerated. The toxicity of carrier-active compounds and of their ultimate compositions varies with the chemical or chemicals involved. The environment surrounding the dyeing equipment where carriers are used should always be weU-ventilated, and operators should wear protective clothing (eg, mbber gloves, aprons, and safety glasses or face shields, and possibly an appropriate respirator). Specific handling information can be obtained from the suppHer or manufacturer. 

Eor printing on polyester, the fixation conditions are more rigorous than on other disperse dyeable fibers, owing to the slower diffusion of disperse dyes in polyester. Eor continuous fixation the prints are exposed at atmospheric pressure to superheated steam of 170—180°C for 6—8 min. A carrier may be added to the print paste for accelerated and fliU fixation. Dry-heat fixation conditions of 170—215°C for 1—8 min are less popular for printed fabrics, but are sometimes employed because of lack of other equipment. 

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