Flow-splitting device

Equipment to measure, proportionally divert, and collect the surface runoff was installed at the end of the irrigation ditch-draining test plot. The measuring apparatus consisted of an up-channel and apron, Parshall flume, stilling well, and water level recorder. A flow-splitting device was attached to the downstream side of the flume. One third of the flow was diverted to a settling tank where it was sampled. A 3-hour retention time was allowed for the water-borne silt to settle. A proportional part of the settleable silt was collected for analysis. 

Figure 12.4. Schematic outline of a feedback control circuit for an active flow splitting device.

Hgure 2 Flow splitting device (A) shows the injector before the splitter, which means that both the flow and the sample are split before going on to the column (B) shows the injector after the splitter, so just the flow is being split, and a full sample injection is going on to the column. 

Figure 5.3 A coextrusion stack die utilizing a flow-splitting device in each melt stream Dual Spiral Systems)...

With open capillary columns and neat CO2, ordinary flame ionization detectors are capable of handling the flow from the heated restrictor. Larger packed columns need a flow-splitting device. 

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 14.18 Flow diagram of split flow capillary LC system. 1. Solvent reservoirs. 2. Model 5000 syringe pump (Varian, Walnut Creek, California). 3. Static mixer. 4. Injection port. 5. Column. 6. Detector. 7. Pressure transducer. 8. Pulse dampener. 9. Purge valve. 10. U-flow controlling device. 11. Waste. 

This micro mixer extends the SAR concepts mentioned above, the sequential lamination being actively supported by the use of a separation plate for flow splitting (see Figure 1.126) [140], As a result of the splitting, two sub-channels are formed, initially at the same height level within the device. Then, one of these sub-channels undergoes a downward movement in a lower level of the device. The two flow channels are so sandwiched, the first carrying the two fluids separate from each other. At certain locations there are conduits within the sandwich to achieve flow recombination on one of the levels of the sandwich. This procedure is repeated many times. 

The simplest approach of splitting one stream into six streams is the use of a fluidic element that directly connects one inlet with six symmetrically arranged outlets [140, 141, 148], Commercial fluid distributors, however, suffer from flow maldistribution, as the smallest deviations in their manufacture have a large impact. Hence specially devices are required for flow splitting to micro devices. A liquid-flow distribution module was one first such device to be realized. 

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]. 

Fig. 2.15. Schematic automated isocratic and gradient elution nemo-liquid chromatograph/ capillary electrochromatograph according Alexander et al. (reproduced from Ref. [44] with permission of the publisher). 1, high-voltage power supply (negative polarity) 2, platinum electrode 3, outlet reservoir vial 4, UV detector with on-column flow cell 5, nanocolumn 6, two-position switching valve 7, jack stand 8, fused-silica make-up adapter (split device) 9, ground cable 10, internal loop micro-injection valve 11, plexiglas compartment 12, autosampler 13, dynamic mixer 14, micro-LC pumps.

It is used to eliminate or reduce weld lines. Two separate injectors or one injector with a splitting device are used to move melt in and out of the cavity from opposite sizes. This type action repeats and is programmed to maximize the best melt flow patterns. 

Requires capillary column (eluent flow rate <5 jl/min) or split devices... 

Motionless mixers are part of continuous-processing devices with no moving parts. They consist of a series of fixed flow-twisting or flow-splitting elements. 

Cf-FAB in all its forms is a low flow-rate technique, i.e., 1-15 pl/min. Therefore, one should use either a microbore or packed microcapillary column, or a conventional colunm in combination with a post-column splitting device [47-48]. 

The benzene fraction was initially examined by GLC using 100 ft. support coated open tubular columns containing Carbowax 1540 polyethylene glycol) and squalane (Figure 3) as the liquid phases. Quantitative data were obtained at 45 °C. on the squalane column with a helium flow of 3.0 ml./min. The Perkin Elmer Model 880 gas-liquid chromatograph, equipped with a stream splitting device and hydrogen flame... 

The ESI source apparently suffers from the limitation that it cannot accept more than 40 to 50 /xl/min of the LC mobile-phase. These flow rates are compatible with 1 mm i.d. LC columns. Alternatively, the effluent from a conventional 4.6 mm i.d. LC column can be partially diverted by a split device to the ESI source. As the ESI-MS arrangement is a concentration-sensitive detector, diverting only a fraction of the LC mobile-phase does not affect sensitivity. Another way of overcoming the problem of coupling LC with 4.6 mm i.d. conventional columns is that of inducing... 

Integrated Microdevices for Medical Diagnostics, Fig. 2 (Left) Schematic diagram of a blood typing biochip. The device contains flow splitting microchannels, a serpentine micromixer, reaction microchambers, and detection microfilters. The reaction chamber holds 3 pi... 

The Agilent 1100 Capillary LC works by splitting the relatively high flow rates to the column. The instrument utilizes a novel flow-monitoring device, called an electronic flow control, which monitors the... 

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