Weighing systems

In some plants the pitches are received and stored as Hquids. Addition to the mixers can be either through a weighing system or positive displacement pumps (3). Except for equipment differences, the results of utilizing Hquid pitch are similar to bulk. 

Care should be taken to avoid powerbil suction or air flow on the mixer or the weigh hopper from which the ingredients feed into the mixer. If the dust-collection suction on the mixer is too strong, vital ingredients may be sucked out. If the dust-collec tion suction on the weighing system is too strong, errors in weighing may result. 

FIG. 21-38 Typical high-precision hqiiid filling and weighing system for packaging 208-L (55-gal) steel drums and similar smaller containers. (Couttesy of H. F. Henderson Industries, Inc., Caldwell, NJ.)... 

Screening and weighing systems storage, transfer, and loading systems and dust handling equipment. 

The systems used for ingredient weighing can vary from a totally manual system to a totally automated system where the ingredients are untouched by human hands. The critical role of the ingredient weighing system. 

Optimized Mixing Line with a Computer Prompted Weighing System... 

Example 13.1 shows one reason that binary polycondensations are usually performed in batch vessels with batch-weighing systems. Another reason is... 

Calcium silicate also finds application in the formation of dry liquids to convert liquids and low viscosity resinous materials to a free flowing powder to enable these to be handled by automatic weighing systems. 

Advances in quality control requirements for rubber compounds have demanded that special care is exercised in the weighing of the various fillers and critical small volume powders necessary for the formulation. Ingredient weighing systems are available which can be tailored to the specific requirements of individual factories. Additional components can include conveyors, bagging units and pneumatic conveyance systems. 

J.M. McKendry, R. Selway, and J.A.W.M. Corver, Method for magnetic field tracking in a NMR check weighing system. United States Patent 7061239 (2006). 

Machines with direct impact on product quality (autoclaves, sterilizing units, labeling system, weighing system, production control system, facility control system, etc.)... 

Behavior of die system after energy breakdown Accuracy of filling lines Transportation speed in a sterilization tunnel Temperature distribution in an autoclave Performance of a washing machine Accuracy of a weighing system... 

In margarine production, raw materials account for about 50% of the margarine cost, actual production costs account for 20%, and other costs are 30% of the total (35). Well-managed formulation and efficient, accurate metering/weighing systems for the various raw materials in the emulsion preparation plant are essential factors for cost-efficient margarine production (35, 76-78). 

As was mentioned earlier, the primary sampling system can be operated either in intervals of constant time or constant mass. The constant mass option makes the design and operation of the secondary, subdivision system simpler. It requires a continuous weighing system, like a belt scale, installed near the primary cutter, preferably before it. This monitors the mass flux of the solids conveyed and adjusts the speed of the primary cutter before each cut this generates a primary increment of constant mass, thus preventing collection of excessive amounts which would overload the secondary system and yet always more than the minimum amount specified for the top size if the handling rate is low. 

Example 13.1 shows one reason why binary polycondensations are usually performed in batch vessels with batch-weighing systems. Another reason is that some polycondensation reactions involve polyfunctional molecules that will crosslink and plug a continuous flow reactor. An example is phenol, which is trifunctional when condensed with formaldehyde. It can react at two ortho locations and one para location to build an infinite, three-dimensional network. This may occur even when the stoichiometry is less than perfect. See Problem 13.3 for a specific example. In a batch polymerization, any crosslinked polymer is removed after each batch, while it can slowly accumulate and eventually plug a flow reactor. 

The REPM are also used extensively in electrobalances, the moving-coil units at the heart of all modern electronic weighing systems, with applications from laboratory to supermarket. It was somewhat surprising that the REPM could also find extensive applications in the field of consumer electronics for loudspeakers, earphones, microphones, etc., first SmCo5 and then 2-17. However, this is undoubtedly a market which Nd-Fe-B will completely take over. 

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