Pumping rate

TPD is frequently used to detenuine (relative) surface coverages. The area below a TPD spectrum of a certain species is proportional to the total amount that desorbs. In this way one can detennine uptake curves that correlate gas exposure to surface coverage. If tire pumping rate of the UHV system is sufiBciently high, the mass spectrometer signal for a particular desorption product is linearly proportional to the desorption rate of the adsorbate [20, 21] ... 

Fluid Temperature, °C Minimum velocity, m/s Pumping rate factor Pressure drop factor Outside tubes Inside tubes... 

When the heat duty requirement, is specified and the fluid temperature change, AT, is fixed, as a result of operating or equipment limitations, the required volumetric pumping rate from the heat balance is... 

Table 2 tabulates the physical property contribution of the required volumetric pumping rate (1 / i p) normalised to assign the value of unity to the lowest data point. 

Fig. 4. Effect of impeller size on mixer pumping rate.

The bulk fluid velocity method relates a blending quaUty Chemscale number to a quaUtative description of mixing (Table 3). The value of is equal to one-sixth of the bulk fluid velocity defined by pumping rate divided by cross-sectional area of the tank (4). 

Under these conditions the maximum heat pumping rate, c the maximum temperature difference across the module, AT and the minimum... 

Plume Containment. WeUs can be placed at a contaminated site to prevent the contamination from spreading further or migrating offsite. In the past, containment efforts often reHed on physical methods such as bentonite slurry trenches, grout curtains, sheet pilings, weU points, and fixative injections. Containment by judiciously placed weUs generally costs less, takes less time to install, and is more flexible because pumping rates and locations can be varied. 

Not only is the type of flow related to the impeller Reynolds number, but also such process performance characteristics as mixing time, impeller pumping rate, impeller power consumption, and heat- and mass-transfer coefficients can be correlated with this dimensionless group. 

If individual controllers are used instead of optimal computer control, several strategies are possible. In one strategy (Lynch and Fiber, 3rd IFAC Symposium on Automation of Mining, Mineral and Metal Proce.ssing, 25-32, 1980) the sluri y-pump rate is controlled to maintain sump-level constant, which results in smooth cyclone operation. The water-feed rate is ratioed to the ore-feed rate, which keeps the circiilating load from oscillating. The ore-feed rate is then controlled to maintain product-particle size. 

The suction line is too small and an increase in temperature and pumping rate cavitates the pump. 

The Pumping number is used to determine the pumping rate Qp of an impeller,... 

This scale-up criterion is based on achieving a constant pumping rate per unit volume with scale-up and therefore leads to similar macromixing on different scales, as the circulation time in the reactor remains constant. 

Lewis (1989) describes the accident, which occurred in Siberia on the night of June 3 and early hours of June 4, 1989. Late on June 3, 1989, engineers in charge of the 0.7 m (28 in.) pipeline, which carried natural gas liquids from the gas fields in western Siberia to chemical plants in Ufa in the Urals, noticed a sudden drop in pressure at the pumping end of the pipeline. It appears that the engineers responded by increasing the pumping rate in order to maintain normal pipeline pressure. 

Single-suction pump Double-suction pump Rating... 

For many process pumps the LIO life is less than 8000 hours, so they usually fall in Classes 4, 5, and 6. A typical system use a running pump rated at 100 per cent... 

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