Pressure drop constant

Steady-state, laminar, isothermal flow is assumed. For a given viscometer with similar fluids and a constant pressure drop, the equation reduces to 77 = Kt or, more commonly, v = r /p = Ct where p is the density, V the kinematic viscosity, and C a constant. Therefore, viscosity can be determined by multiplying the efflux time by a suitable constant. 

Dyna Sand Filter. A filter that avoids batch backwashing for cleaning, the Dyna Sand Filter is available from Parkson Corporation. The bed is continuously cleaned and regenerated by recycling solids internally through an air-lift pipe and a sand washer. Thus a constant pressure drop is maintained across the bed, and the need for parallel fdters to low continued on-stream operation, as with conventional designs, is avoided. 

Condensation reduces the volume of the vapor present and can be assumed to occur at a constant pressure drop. 

For a constant pressure drop and temperature filtration process all the parameters in Equation 9, except V and x, are constant. Integrating Equation 9 over the limits of 0 to V, from 0 to x, we obtain ... 

Constant-pressure drop filtration can result in saturation or blockage of the filter medium. The network of pores within the filter medium can become blocked because of one or a combination of the following situations ... 

CHE 440 Filtration Experiment... find the parameters (discussed below) that govern constant pressure drop cake filtration... 

The system described in question 4 has an auxiliary time of = 1800 sec. Determine the total filtration time at constant pressure drop, cake thickness and filtrate volume. 

The collector configuration can be single compartment or multicompart-ment. Multicompartment designs are used where it is important to maintain a relatively constant pressure drop during collector operations. Multicompartment design allows compartments to be taken off-line for cleaning or maintenance with the collector system still in operation. 

Constant pressure drop is maintained during operation. Taking as the basis one revolution of the drum, the time per revolution and submergence fraction, respectively, can be defined as... 

Figure 4-64. Variable orifice MultiVenturi Flexitray scrubber at essentially constant pressure drop maintains good efficiency over wide flow rates. By permission, Koch Engineering Co., Inc.

Increase the tube diameter, either to maintain a constant pressure drop or to scale with geometric similarity. Geometric similarity for a tube means keeping the same length-to-diameter ratio L/dt upon scaleup. Scaling with a constant pressure drop will lower the length-to-diameter ratio if the flow is turbulent. 

The same result is obtained when the fluid is compressible, as may be seen by substituting Sr = Si = S into Equations (3.40) and (3.41). Thus, using geometric similarity to scale isothermal, laminar flows gives constant pressure drop provided the flow remains laminar upon scaleup. The large and small reactors will have the same inlet pressure if they are operated at the same outlet pressure. The inventory and volume both scale as S. 

Constant-Pressure Scaleups for Packed Beds. A scaleup with constant pressure drop can be achieved in a packed bed just by increasing the diameter to keep a constant gas velocity m. This gives... 

Static mixers are typically less effective in turbulent flow than an open tube when the comparison is made on the basis of constant pressure drop or capital cost. Whether laminar or turbulent, design correlations are generally lacking or else are vendor-proprietary and are rarely been subject to peer review. 

Figure 11.44 correlates the liquid and vapour flow rates, system physical properties and packing characteristics, with the gas mass flow-rate per unit cross-sectional area with lines of constant pressure drop as a parameter. 

Figure 6.1 Critical heat flux versus mass flow rate for constant pressure drop. (From Maulbetsch and Griffith, 1965. Reprinted with permission of Massachusetts Institute of Technology, Cambridge, MA.)... 

An aqueous slurry containing 1.5 lbm of solid per gallon of liquid is pumped through a filter cloth by a centrifugal pump. If the pump provides a constant pressure drop of 150 psig, how long will it take for the filter cake to build up to a thickness of 2 in. The density of the filter cake is 30 lbm/ft3, and its permeability is 0.01 Darcy. 

A rotary drum filter 6 ft in diameter and 8 ft long is to be used to filter a slurry. The drum rotates at 0.5 rpm, and one-third of the drum s surface is submerged in the slurry. A vacuum is drawn in the drum so that a constant pressure drop of 10 psi is maintained across the drum and filter cake. You test the slurry in the lab by pumping it at a constant filtrate rate of 20 gpm through 1 ft2 of the drum filter screen and find that after 1 min the pressure drop is 8 psi and after 3 min the pressure drop is 12 psi. How long will it take to filter 100,000 gal of filtrate from the slurry using the rotary drum ... 

A rotary drum filter is used to filter a slurry. The drum rotates at a rate of 3 min/cycle, and 40% of the drum surface is submerged in the slurry. A constant pressure drop at 3 psi is maintained across the filter. If the drum is 5 ft in diameter and 10 ft long, calculate the total net filtration rate in gpm that is possible for a slurry having properties as determined by the following lab test. A sample of the slurry was pumped at a constant flow rate of 1 gpm through 0.25 ft2 of the filter medium. After 10 min, the pressure difference across the filter had risen to 2.5 psi. The filter medium resistance may be neglected. 

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