Units, split

Centrifugal compressor cases are classified as horizontally split or vertically split (Figures 12-40A-C). The 5th Edition, April, 1988, API Standard 617 refers to the horizontally split style as Axial Split and vertically split units as Radial Split The first terminology is more standard than that of the API-617. Figure 12-40D illustrates one flow arrangement for back-to-back internal flow, with the following advantages ... 

The horizontally split units are accessibie for inspection and cieaning. Removai of the upper haif of the case permits access to the rotor, diaphragms, guide vanes, and other internai parts. Journai and thrust bearing and seais, however, can be examined or removed without disturbing the upper haif of the case. 

Larger split packages must be piped on site by normal methods, and then processed and charged as an open plant. Split unit evaporators should not be located more than 5 m higher than their condensers (see Section 11.8) See also multi-splits, Section 28.8. 

Figure 1.5 Photograph of the liquid-flow splitting unit for liquid/liquid processing with three tanks and six separation-layer micro mixers [8].

Schenk, R., Hessel, V., Hoemann, C., Kiss, )., Lowe, H., Schoneeld, F., Numbering-up of micro devices a first liquid-flow splitting unit, Chem. Eng. Technol. 26, 12 (2003) 1271-1280. 

Figure 4.91 Demonstration of flow guiding in a liquid flow-splitting unit which consists of three tanks, six interdigital separation-layer micro mixers, a multiple channel segmenter and six tubular sections [140].

Figure 4.99 Stack of three liquid-flow splitting units comprising three damping tanks and three inlet and 18 outlet tubes. Some of the tubes are not visible since they are on the rear of the tank [141 ].

Liquid-flow splitting unit with untreated mixers... 

Figure 4.101 Experimental determination of the deviation of the total volume flow for the liquid-flow splitting unit alone and with six impinging-jet micro mixers attached. Concerning the latter, two cases were studied. First, the six best micro mixers were selected from 18 according to the minimal pressure drop deviation taking into account both outlet holes. Second, the same selection was done but relying on one hole only [141 ].

The predictions of the simulations were corroborated by experimental findings. For the liquid-flow splitting unit without an additional micro device as flow resistor, a minimum/maximum flow deviation of about 6% (see Figure 4.101) was found at a low pressure drop below 10 mbar [141]. The maximum flow deviation for the liquid flow-spitting unit equipped with these six selected impinging-jet mixers amounted for initial tests to 11% (4% standard deviation) at 64-74 mbar pressure drop (see Figure 4.101). By optimization of material pretreatment and micro fabrication, a minimum/maximum deviation of the water distribution below 5% and a standard deviation below 2% were finally obtained. 

The functioning of the liquid-flow guiding was demonstrated with the formation of iron rhodanide as a test reaction in a device built of three liquid-flow splitting units and six interdigital separation layer micro mixers (see Figure 4.91) [141]. 

R. Schenk, V. Hessel, C. Hofmann, H, Lowe, F. Schonfeld, Novel liquid flow splitting unit speciflcally made for numbering-up of liquid/liquid chemical microprocessing, Chem. Eng. Technol. 2003, 26, 1271-1280. 

Air Handler Device that blows air across a split-unit central air-conditioning evaporator coil into the air ducts of a building. 

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