Design units

Sludge-blanket clarifiers are difficult to start up because the first blanket must be estabUshed, and large-scale units require extensive excavation. Sizes range from 600 x 600 mm to 50 x 50 m. Precipitation and crystallization can be carried out in similar hopper-designed units, having overflow rates of 80 m/h or higher. 

These unit area values, plotted as a function of the feed concentration, will describe a maximum value that can be used to specify the thickener design unit area for the particular underflow concentration... 

Operating experience has proven that unless a continuous program of required lubrication is followed, even the most well-designed units are sure to fail. A proper lubrication management program must incorporate a monthly lubrication schedule, an evaluation of new lubrication products, and supervision to ensure the prescribed procedures are carried out by maintenance personnel. 

An increase in steam pressure over design will not increase vapor handling capacity for the usual fixed capacity ejector. The increased pressure usually decreases capacity due to the extra steam in the diffuser. The best ejector steam economy is attained when the steam nozzle and diffuser are proportioned for a specified performance [8]. This is the reason it is difficult to keep so-called standard ejectors in stock and expect to have the equivalent of a custom designed unit. The throttling type ejector has a family of performance curves depending upon the motive steam pressure. This type has a lower compression ratio across the ejector than the fixed-type. The fixed-type unit is of the most concern in this presentation. 

This velocity is too high for satisfactory operation. Therefore, the only way to get more flow area is more tubes and requires the same size shell as the previously designed unit. I recommend using the unit with 1-in. tubes. 

The value of this relation is that it serves as a maximum limit that may he expected from a designed unit when comparing design Q/A versus Equation 10-139. 

What are the characteristics of designed units about the domain of micro-macro thinking, leading to units within which design criteria are realised (transformations 2 3) ... 

The probability that any given one of the v units designated for cross-linking has another such unit situated next to it within the required volume element 5F is (v — l)8V/Vj where V is the total volume. The probability that another unit selected from the remaining v — 2 designated units is similarly paired is (v S)8V/Vj and so forth. The probability that all of them are paired is ... 

Physical property data and sometimes reaction rate characteristics are required for making relief sizing calculations. Data estimated using engineering assumptions are almost always acceptable when designing unit operations because the only result is poorer yields or poorer quality. In the relief design, however, these types of assumptions are not acceptable because an error may result in catastrophic and hazardous failures. 

Collaborations as first-class design units were first introduced in Helm, Holland, and Gangopadhyay s contracts and developed in Trygve Reenskaug s [Reenskaug95] method and tool OORAM. 

As we discussed in Section 2.6, interface-centric design leads us toward treating these open collaborations as design units. Each interface of a component represents one of its roles, which is relevant only in the context of related roles and interactions with others. An open collaboration is a grouping of these roles into a unit that defines one design of a certain service (see Figure 4.17). 

This text deals with the physical operations used in the chemical and allied industries. These operations are conveniently designated unit operations to indicate that each single operation, such as filtration, is used in a wide range of industries, and frequently under varying conditions of temperature and pressure. 

Substitution of less expensive off-the-shelf vessels, piping, and pumps in place of costly, custom-designed units... 

Cover design United Nations Office at Vienna, PRES... 

There should be a designated unit to review written and oral complaints. 

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