Flow-rate controller

The most accurate flow rate control can be achieved by using the loss-in-weight method. The total amount of material required for a downstream process is first added to a tank or hopper scale. As the material is discharged, the loss-in-weight is monitored and used to modulate the discharge valve or gate to achieve the desired flow rate. 

Flow rate controller An item of equipment that will control the flow rate at a fixed value for a given pressure difference. 

Mechanical constant flow rate controller See Flow rate controller. 

One to 5 g material was mixed by a glass rod with 1 mL/g material of "stopping solution", that contained 25 mg/mL of ammonium sul-famate, 25 mg/mL of sodium ascorbate, and 2.0-2.5 mg/mL of cis-2,6-dimethylmorpholine (cis-DMM), and was adjusted to pH 1 with H2S0. The pH of the slurry was readjusted to 1 with concentrated H2S0. The mixture was stirred with 10 g Celite 560 (from Johns Manville Corp. previously sifted to remove< 60 mesh particles), and packed dry in a "Monoject" plastic 50 mL syringe barrel (Shermwood Industries) prepacked with 8 g Celite. The column was eluted (without flow-rate control) with 100 mL... 

Difficult quantitation (sample size, CO2 flow-rate control)... 

Consider the liquid flow rate controller in Fig R5.3. We want to keep the flow rate q constant no matter how the upstream pressure fluctuates. Consider if the upstream flow Q drops below the steady state value. How would you choose the regulating valve when you have (a) a positive and (b) a negative proportional gain ... 

Figure 10.1. Cascade control of the temperature of a furnace, which is taken to be the same as that of the outlet process stream. The temperature controller does not actuate the regulating valve directly it sends its signal to a secondary flow rate control loop which in turn ensures that the desired fuel gas...

A combustion temperature that is low enough to protect the flow-rate control valve from heat and high enough to ignite the combustible gas when air is introduced into the ramburner the combustion temperature of the gas-generating pyrolant is approximately 1400 K. 

Ignite the flame and ensure that it is blue with a very faint tinge of yellow above the primary cone. If it appears to be too fuel lean or fuel rich, adjust the fuel flow rate control accordingly. 

Thus, the scalers on the dosimeter module may be set to display in mCi of Rb-82, since the circuit incorporates an adjustable pulse divider corresponding to the proportionality constant. In addition to displaying the activity of Rb-82 passing the detector at any instant, the second scaler provides a summation of total activity eluted. The flow rate constant, F, is set equal to the flow rate control of the infusion pump. 

Flow rate control of the solvent pump was difficult because 0.2 L/h is near the low end of the solvent pump s capacity. 

Control of the field occurs on two levels. The upper level Is the supervisory control and data acquisition (SCADA) system whose main responsibility is well flow rate control, well testing, production allocation, accounting and general field monitoring. The SCADA system is operated from the Main Operations Center (MOC) which is remote from all three GCs. The second level of control is process control in the individual GCs. Flow to the GCs Is normally controlled by the SCADA system (HOC operator), but the GC operator can override and control well flow rates in case of SCADA system failure or other unusual circumstances. The GC operator and the MOC operator communicate via a dedicated telephone connection. 

Figure 15.23. Hypersorber continuous moving bed gas phase adsorption system (See Mantell, Adsorption, McGraw-Hill, New York, 1951). (a) Schematic pattern of flows of gas and solid adsorbent (Hengstebeck, Petroleum Processing, McGraw-Hill, New York, 1959). (b) Solids flow rate control mechanism, (c) Typical separation performance.

Sample analysis was performed by using an Applied Biosystems (Foster City, CA) API 3000 triple quadrupole mass spectrometer equipped with a TurboIonSpray source and an Agilent 1100 capillary HPLC system (Palo Alto, CA). The capillary HPLC system included a binary capillary pump with an active micro flow rate control system, an online degasser, and a microplate autosampler. The analytical column was a 300 pm I.D.x 150 mm Zorbax C18 Stablebond capillary column (pore size 100 A and particle size 3.5 pm). The injection volume was 5 pL, and a needle ejection rate of 40 pL/min was used. The pLC flow rate was 6 pL/min. In order to minimize dead volume before the column, the autosampler was programmed to bypass the 8 pL sample loop 1.5 min after injection. The mobile phase consisted of (A) 2 mM ammonium acetate (adjusted to pH 3.2 with formic acid) in 10 90 acetonitrile-water, and (B) 2 mM ammonium acetate in 90 10 acetonitrile-water. The percentage of mobile phase B was held at 32 % for the first minute, increased to 80 % over 8 min, and then increased tol00% over the following 1 min. 

Feeding flow rate control system based on glucose concentration measured in real time (adapted from Ozturk et a ., 1997). 

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