Pumps/pumping volume efficiency

JL-900 Snow White is a high volume air sampler. It is meant to be used when trying to find even the smallest amounts of radiation in the atmosphere. Air volume is calculated from the pressure difference over the calibrated flange, also in the carbon line, which is equipped with a valve. Vacuum is set to 100 mbars which lies in the middle of the pump s efficiency of 200 mbars and leaves lots of reserve power to hold the air volume quite stable even when the filter gets dirty. The filter is set in a cassette... 

The pump efficiency function, fpj(U), is frequently available as a low-order polynomial in U, in which case the differentiation d fpj/dU is a simple matter. Alternatively, the differentiation may be carried out graphically by finding the tangent to the fpjfU) vs. U curve. However, before we can solve equation (23.35), we still need to find the total derivative of pump speed to pump volume flow, dN/dQ, when the power supplied is kept constant. To do this we proceed as follows. 

A-l. Extractor Column Extraction Efficiency. Extraction of the PAHs from the generated solutions was accomplished by pumping volumes varying between 5.0-25.0 mL through the extractor column. Over this range, extraction efficiencies are quantitative for 11 of the 12 compounds studied in this investigation. Benzene was not extracted efficiently by the extractor column. The solubility of benzene, therefore, was determined by direct injection of 23.2 /xL of the generated solutions via a sample loop. 

The excited ions of the pumped laser materials in a laser resonator can be de-excited by various radiative (either laser or luminescence) and nonradiative (electron-phonon interaction or energy transfer) processes. Also, the amount of ions participating in laser emission is dependent on the laser emission efficiency ( /i). The laser emission is produced by the excited ions inside the laser mode volume and pumped above the threshold. The excited ions inside the pumped volume but outside the laser mode volume and those that form the inversion of population at the laser threshold can be de-excited by luminescence and nonradiative processes. 

The relevance of the superposition integral of the laser mode and the pumped volume t]y is determined by the regime of laser emission. The material factors that influence the laser threshold and thus the laser emission efficiency rii, in the case of CW emission, have been evaluated. Several of these factors, such as the emission quantum efficiency and the effective lifetime, can be influenced by the conditions of the experiment (concentration of the doping ions, temperature), whereas the quantum defect ratio is influenced by the pump wavelength. 

Pump power is equal to pump energy per unit mass of fluid multiplied by fluid mass flow rate. Pump energy per unit mass of fluid is equal to fluid specific volume times pump pressure rise divided by pump fractional efficiency. An increase in fluid mass flow rate results in a double penalty if system pressure drop increases due to the higher fluid mass flow rate. 

Because of the low efficiency of steam-ejector vacuum systems, there is a range of vacuum above 13 kPa (100 mm Hg) where mechanical vacuum pumps are usually more economical. The capital cost of the vacuum pump goes up roughly as (suction volume) or (l/P). This means that as pressure falls, the capital cost of the vacuum pump rises more swiftly than the energy cost of the steam ejector, which iacreases as (1 /P). Usually below 1.3 kPa (10 mm Hg), the steam ejector is more cost-effective. 

The large variety of displacement-type flmd-transport devices makes it difficult to list characteristics common to each. However, for most types it is correct to state that (1) they are adaptable to high-pressure operation, (2) the flow rate through the pump is variable (auxiliary damping systems may be employed to reduce the magnitude of pressure pulsation and flow variation), (3) mechanical considerations limit maximum throughputs, and (4) the devices are capable of efficient performance at extremely low-volume throughput rates. 

Equipment Constraints These are the physical constraints for individual pieces of eqiiipment within a unit. Examples of these are flooding and weeping limits in distillation towers, specific pump curves, neat exchanger areas and configurations, and reactor volume limits. Equipment constraints may be imposed when the operation of two pieces of equipment within the unit work together to maintain safety, efficiency, or quahty. An example of this is the temperature constraint imposed on reactors beyond which heat removal is less than heat generation, leading to the potential of a runaway. While this temperature could be interpreted as a process constraint, it is due to the equipment limitations that the temperature is set. 

The organisms in a digester are most efficient when food is furnished them in small volumes at frequent intervals. Fresh sludge solids should therefore be pumped to the digester as often as practical, at least twice a day for the smallest plants and more frequently where facilities and operators attention are available. This, of course, fits in with the proper schedule of removing sludge from settling units before it becomes septic. 

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