Multiport

The commercial appHcation of this concept (68) is portrayed ia Figure 8, which shows the adsorbent as a stationary bed. A Hquid circulating pump is provided to pump Hquid from the bottom outiet to the top inlet of the adsorbent chamber. A fluid-directing device known as a rotary valve (69,70) is provided. The rotary valve functions on the same principle as a multiport stopcock in directing each of several streams to different lines. At the right-hand face of the valve, the four streams to and from the process are continuously fed and withdrawn. At the left-hand face of the valve, a number of lines are coimected that terminate in distributors within the adsorbent bed. 

Twin oil coolers (Figure 15-3) should be provided and piped in parallel using a single multiport transflow valve to direct the oil flow to the coolers. The water should be on the tube side and the oil on the shell side. The oil-side pressure should be greater than the water-side pressure. This ratio is no assurance that water will not enter the system in the event of a tube leak, but it does reduce the risk. The oil system should be equipped with twin full-flow oil filters located downstream from the oil coolers. Since the filters are located downstream from the oil coolers, only one multiport transflow valve is required to direct the oil flow to the cooler-filter combinations. Do not pipe the filters and coolers with separate inlet and outlet block valves. 

Figure 4.1 Schematic diagram of a coupled column system. The first column (ID) is connected to the second column (2D) tlirough the interface or valve system. The interface can be a diiect coupling, a live T-union, a complex multiport valve, or a thermal or cryogenic modulation system. The stimulus can be the switching of the valve, abalancing pressure to divert flow towards 2D, an added flow that is used in pressure tuning, or the drive mechanism for the modulator. The line to detector 1 will normally be a non-retaining section of column. In a two-oven system, ID and 2D will be in different ovens the dotted line indicates separately heated zones.

For superheated steam, the sample points should be designed and installed to permit correct isokinetic sampling. A modified multiport nozzle design ensures that the velocity of the steam entering the sample nozzle is the same as the velocity of steam in the header. The design incorporates a small, high-quality water delivery tube, used to inject water and remove superheat before sample extraction. 

It is preferable to sample vertical pipelines rather than horizontal lines (ideally when the flow of steam is downward rather than rising). Sampling in the vicinity of bends, elbows, and valves should be avoided. At the sample point, the multiport valve should be installed perpendicular to the flow of steam. 

The etched micro channels have different widths for more stable flow, e.g. to avoid a dependence on capillary forces in the reservoirs [18]. The glass chip is glued to a polymer caddy for interfacing with a multiport control device, the Caliper 42 Workstation. 

A 10 pi volume of the aldehyde was placed in three reservoirs and 10 pi of the 1,3-diketone in three other reservoirs [18]. The chip was inserted into the interfacing device and a script for defining pressures was set in the multiport control using a Caliper 42 Workstation . A 30 min run was carried out. An eight-peristaltic pump system was used as pressure or vacuum source. N o active quenching was performed, but it was assumed that by dilution in the collection reservoir reaction was stopped or at least notably slowed. 

Figure 4.2 shows the complete CBMS II system. The main unit is comprised of three modules, the Biosampler Module, the Sample Introduction Module (SIM), and the Mass Spectrometer Module. The Biosampler Module houses the virtual impactor air particle concentrator and is only needed for the biological agent monitoring mode. The Sample Introduction Module contains the multiport sampling valve with its three input connections ... 

Yoshida et al. developed similar numbered-up capillary pilot reactors for free radical polymerization (Iwasaki et al. 2006). The capillaries were either arranged in parallel fashion similar to conventional multitube reactors or consecutively branched by multiport valves. 

Where binary, ternary or quaternary gradient elution (p. 91) is required, a microprocessor controlled low-pressure gradient former is the most suitable (Figure 4.31(c)). The solvents from separate reservoirs are fed to a mixing chamber via a multiport valve, the operation of which is preprogrammed via the microprocessor, and the mixed solvent is then pumped to the column. For the best reproducibility of solvent gradients small volume pumps (< 100 gl) are essential. 

A dissolution testing apparams consists of a set of six or eight thermostatted, stirred vessels of an established geometry and volume from the USP guidelines. The dissolution apparatus provides a means to dissolve each sample, but does not provide a means to determine the concentration of the aetive ingredient in the bath. In the most well-established scheme, sipper tubes withdraw samples from each dissolution vessel and send them through a multiport valve to a flow cell sitting in the sample chamber of a UV-vis spectrophotometer. In recent years, moves have been made to make in situ measurements in the dissolution baths by means of fiber-optic probes. There are three possible probe implementations in situ, down shaft, and removable in situ (see Table 4.2). 

Most of the frequently used comprehensive 2D LC systems employ a microbore HPLC column in the first dimension, operated at low flow rate, both under isocratic and gradient conditions. This enables the transfer of fractions of small volume via the multiport valve equipped with two identical... 

IMPORTANT NOTE Use high-purity nitrogen only, otherwise impurities of 02 will oxidize the lipids (see Critical Parameters). A multiport nitrogen evaporator equipped with a distribution manifold and water bath is highly recommended for this application (Fig. Dl.2.1). 

Figure D1.2.1 An example of a multiport (24-position) nitrogen evaporator (N-EVAP, Organomation Associates, reprinted with permission).

H-6 compn then the w/expl mixt flows into a vac kettle where the w is removed. The dried expl is then dispensed thru a multiported dispenser to an endless steel belt where it solidifies and is broken into flakes as it flows off the belts. Remelting and compn adjustment to form new HBX types or H-6 is then easily performed ... 

We have demonstrated in this paper that two and four samples can be extracted in parallel with supercritical carbon dioxide without significant impact on data quality. Modifications made to an off-line extractor involved addition of a multiport manifold for the distribution of supercritical fluid to four extraction vessels and of a 12-port, two-way switching valve that allowed collection of two fractions per sample in unattended operation. The only limitation that we have experienced with the four-vessel extraction system was in the duration of the extraction. When working with 2-mL extraction vessels and 50-/zm restrictors, and using the pressure/temperature conditions mentioned above, the 250-mL syringe pump allows us a maximum extraction time of 60 min. During this time, two 30-min fractions can be collected with the present arrangement. 

The key part of the system is the multiport valve, which interconnects the different parts and solutions used by the system. The common port is connected to a reversible pump with the retention coil placed in between. The pump is connected to the carrier solution reservoir. The common port can access any of the other ports, which lead to sample, standard solutions or reagents, mixing chamber and sensor array, by electrical rotation of the valve. Since the system is bidirectional, volumes can not only be propelled directly to the detector, but also be injected into the retention coil, therefore merging accurate aliquots of different solutions. In order to assure proper mixing of the solutions not only via diffusion... 

The interconnect of the Samson Box was quite novel, ft was called sum memory and was implemented by parallel loading counters and then writing the result back into RAM. The connection memory acted as a double-buffered multiport memory by dividing the memory into quadrants as shown in figure 5.5. 

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