Cycles bagging

Data for such a direct comparison have been pubhshed elsewhere (13), along with a complete description of the tests. A summary of the results is shown in Figure 8, where the conversion efficiency for each of the square channel substrates is plotted against the conversion efficiency for each of the sinusoidal channel substrates, for the peirticular FTP test portion and for each of the three measured gases (HC, CO, and NOx). Here, only the latter part of the first test cycle (bag IB), all of the second cycle (bag 2), and only the latter part of the third test cycle (bag 3B) are included in the comparison. The slope of the best-fit fine to these data is 1.004 0.003, demonstrating that the test results are similar for the two structures, as the Heat Mass Transfer Factor predicts. 

Cold-isostatic-pressing foUowed by vacuum sintering or HIP is also used to manufacture smaller intricate shapes. In this instance beryUium powder is loaded into shaped mbber bags and pressed isostaticaUy in a pressure chamber up to 410 MPa (60,000 psi). After the pressing operation the mbber bag is stripped from the part which is then vacuum sintered to about 99% of theoretical density at about 1200°C. If full theoretical density is required, the sintered part may be simply given a HIP cycle because there is no open porosity after vacuum sintering. In a similar manner, conventional axial cold-pressing... 

Pulse-jet cleaning (above) uses a controlled blast of compressed air from the primary into the secondary nozzle, which is magnified by induced air being drawn into the bag. The sudden release of air causes the bag to expand fully, throwing the dust from the outer surface. Dislodged dust falls into the collection hopper. At right, types of duty cycles... 

Fabric-filter systems, commonly called bag-filter or bag-house systems, are dust-collection systems in which dustladen air is passed through a bag-type filter. The bag collects the dust in layers on its surface and the dust layer itself effectively becomes the filter medium. Because the bag s pores are usually much larger than those of the dust-particle layer that forms, the initial efficiency is very low. However, it improves once an adequate dust-layer forms. Therefore, the potential for dust penetration of the filter media is extremely low except during the initial period after startup, bag change, or during the fabric-cleaning, or blow-down, cycle. 

Under controlled conditions (e.g., in the laboratory), the inherent collection efficiency of fabric filters approaches 100 per cent. In actual operation, it is determined by several variables, in particular the properties of the dust to be removed, choice of filter fabric, gas velocity, method of cleaning, and cleaning cycle. Inefficiency usually results from bags that are poorly installed, torn, or stretched from excessive dust loading and excessive pressure drop. 

Pressure bag molding This is a take-of to vacuum bag molding where the bag and mold is placed in a closed system and is subjected to pressure during the curing cycle. 

Bags are normally reusable after cleaning and may last for several cycles before changing becomes necessary. Bags should be cleaned or changed when differential pressure reaches 20 to 25 psid. 

FIG. 17-59 Three -compartment bag filter at various stages in the cleaning cycle. (Wheela-brator-Frye Inc.)... 

Few basic studies of the efficiency of bag filters have been made. Increased dust penetration immediately following cleaning has been readily observed while the dust layer is being reestablished. However, field and laboratory studies have indicated that during the rest of the filtration cycle the effluent-dust concentration tends to remain... 

To store a block for later cutting, place in an airtight container, preferably one that is not too mnch bigger than the block. Small Zip-lock bags are good for this. Place into an nltralow-temperature freezer (-70°C) as soon as possible. Avoid freezers with antomatic freeze-thaw cycles snch as frost-free types. 

VA, VB 3-way solenoid valves controlling the flush/evacuation cycle of collecting bags. 

CTCL Extracorporeal Inject 200 meg into the photoactivation bag during collection cycle using the UVAR photopheresis system, 2 consecutive days every 4 wk for a minimum of 7 treatment cycles. 

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