Inlet valve position, determination

Figure 7-8. The new inlet valve position can be determined from the valve curve.

Step 6 Calculate step on the inlet valve. Now that the new inlet valve e after the breaker opening has been determined, this ean be translated into a valve position. This is a simple proeess using the valve eharaeteristie of the manufaeturer. Eigure 7-8 shows a typieal butterfly valve eharaeteristie. This eurve shows the ealeulated Using the valve eurve, the new valve position is determined. 

Step 9 Apply steps to inlet and bypass valves. Now that the new inlet and bypass valve positions are determined, the outputs to the valves can be changed. Before doing this, however, due to flexibility in the control system, it is still possible to manipulate the step on the valve. For this purpose, the control system provides scaling factors between the actual step and the calculated step. These scaling factors can help compensate for calculation errors and/or process dynamics. This is formulated as ... 

The inlet and outlet flows will face resistance from pipelines and valves and may be modelled using the methods of Chapters 6 and 10. The variables necessary to determine these flows are the upstream pressure, the upstream specific volume, the downstream pressure and the valve position. The internal mass flows, Wj, i =, ...,N, are calculated as the flows through each nozzle, and this procedure may be carried out iteratively at each timestep. Calculation of the overall performance of the turbine at each timestep follows the following sequence. 

The second-level components are the 3-way valve 3W and the two 4-way valves 4W-I and 4W-II. The equipment states of these three valves can determine the system configuration. The position of valve 3W determines the route of inlet air flow. The fresh air can either be directed to the heater or simply bypass it. The position of valve 4W-I defines the connections between the alumina beds and their air supplies. The air consumed in each bed can be taken either from system inlet (for regeneration or cooling) or from the lower port of proportionating valve (for dehumidification). The position of valve 4W-II governs the destinations of the exit airs from these two beds, i.e. the air can be either discharged or recycled. 

For GAS experiments the autoclave is filled with the non-volatile component and closed. Then, solvent is drawn into the evacuated vessel. With a pneumatically driven compressor a thermostated buffer vessel is filled with gas. From there it enters the high-pressure cell through the filter or the gas inlet at the top. Thus, the amount of gas can be determined by pvT measurement. Very fast pressure built-up rates can be achieved. After precipitation, the autoclave is placed in vertical position. The solution is then filtered and drained through the bottom valve. During that process the pressure is held constant by adding gas from the top. After the filtration step the solids can be washed with additional gas to remove any residual solvent. 

The ventilation factor and the room pressure determine the volume of air that has to be let in and thus the dimensions of the air duct, the number of inlet grids and the position of the metering valve of the involved supply channel or the area of the involved overflow grid. The heat burden and the admitted airflow rate furthermore determine the maximum inlet air temperature or the required capacity of any after-hearing radiator. 

Avoid the use of isolation valves on the inlet or outlet of relieving devices. If a shutoff valve (often referred to as a stop valve) is to be added for maintenance purposes, the installer should consult the applicable codes to determine whether it is permitted. A stop valve must have a port area greater than or equal to the inlet size of the relieving device. Twin relieving devices are often installed with positive isolation provided by three-way valves interlocked so that one relieving device is always in service. 

The microchips are coupled to an SIA system for fully automated determination of MSG. The system is constructed with a syringe pump, a 10-multiposition valve, an enzymatic microchip, and a fluorescence detector. The inlet capillary of the single-channel microchip is connected to a 10-position valve, but in this case, only four ports are used (only beads, sample, waste, and microchip position). The whole system is controlled by a computer using software developed in-house. The fluorescence of the NADH peak is recorded by a chart recorder. 

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