Backpressure regulators

The high pressure continuous reactor consists of five Kenics type in-line static mixers, that were connected in series [3]. Each reactor unit has 27 Kenics elements and dimensions of 19 cm tube length and 3.3 mm inner diameter. Acetonylacetone and 1 % NaOH aqueous solution were pumped into the in-line static mixer reactor using two independent HPLC pumps. The in-line static mixer reactors were immersed in a constant temperature controlled oil bath at 200 °C so that the reaction mixture was heated to the reaction temperature. When the reaction was completed, the fluid was cooled down rapidly in a constant temperature cold bath at 0 °C. At the end of the cooling line, a backpressure regulator was placed to allow experiments to be run at 34 bar. 

Figure 6.7 depicts an autosampler employed in a jtPLC system. Figure 6.8 details the autosampler component. Samples are transferred from the desired well in the microtiter plate into the columns of the Brio cartridge. If a 384-well plate is employed, the autosampler will carry out 3 sets of 8 injections into the columns, for a total of 24 columns. The solvent (mobile phase) does not circulate in the cartridge but is diverted into a backpressure regulator located in the waste line (Figure 6.2). This process of injection is known as stop-flow injection. After all samples are placed into the injection pits of the 24 columns in the cartridge (Figure 6.5), a clamp containing a seal...

If the nature of the utilization equipment is such that it may induce a vacuum at the meter, install a backpressure regulator downstream from the meter. 

Without backpressure regulation for each channel, it is necessary to minimize the flow rate fluctuation over time. The relative standard deviation (RSD%) in retention time variation among the eight channels over 1 month for compounds A and B was less than 2% and for C and D it was less than 1%. The RSD% for all channels over a 1-month period for compounds A to D was 3.2, 2.4,1.6, and 1.5%, respectively. Therefore, this system is well suited for combinatorial library analysis. The UV chromatograms from channel 5 from different days are shown as an example in Fig. 2A. The retention times of the four compounds (compounds A to D) from all eight channels during a 1-month period are shown in Fig. 2B. 

Figure 7.2.4 Experimental set-up used for SFC-NMR experiments (a) modifier pump (b) SFC pump (c) CO2 cylinder with dip-tube (d) cryostat (e) GC oven with mixing chamber and separation column (f) injection valve (g) UV detector (h) NMR magnet (i) backpressure regulator or restrictor (j) hardware control unit...

Figure 5.2.1. Simplified diagram of a Py-GC system (not to scale). The pyrolyser is schematized as a heated filament type. A piece of a deactivated fused silica line is passed through the injection port of the GC and goes directly into the pyrolyser. This piece of fused silica is connected to the column, which is put in the GC oven. The pneumatic system consists of (1) a mass flow controller, (2) an electronic flow sensor, (3) a solenoid valve, (4) a backpressure regulator, (5) a pressure gauge, and (6) septum purge controller. The connection (7) is closed when working in Py-GC mode, and connection (8) is open. (Connection (7) is open when the system works as a GC only.) Connection (9) is closed and connection (10) is open when the GC works in splitless mode (purge off). Connection (10) is closed and connection (9) is open when the GC works in split mode (purge on). No details on the GC oven or on the detector are given.

Air bubbles in detector. —> Install backpressure regulator after detector. 

Air in the detector cell. —> Clean cell. Use backpressure regulator at detector outlet. 

Solvent degassing and backpressure regulators after the detector minimize bubble formation. It is a helpful practice to perform blank runs every day to provide reference data that can be consulted at a later date. 

Figure 7.1 Design of an extruder plasticating barrel (a) feed hopper (b) heaters (c) screw (d) thermocouples (e) backpressure regulating valve (f) pressure gauges (g) breaker plate and screen pack...

The main components of a typical SF extractor are a gas supply, a high pressure pump, a controller used to pressurize the gas, a temperature controlled oven, an extraction vessel, a restrictor (backpressure regulator) and a collection device (Figure 2.21). 

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