Module 3 Flashcards
________ is an essential element of many pharmaceutical processes. The ability to propel fluids through pipes and to direct materials from one
location to another is central to the successful manufacture of many products.
Fluid flow
_________ are a form of matter that cannot achieve equilibrium under an applied shear
stress but deform continuously, or flow, as long as the shear stress is applied.
Fluids
___________ is a property that characterizes the flow behavior of a fluid, reflecting the
resistance to the development of velocity gradients within the fluid.
Viscosity
Fluids having constant viscosity
and a zero shear rate at zero shear
stress
Newtonian Fluid
Fluids having variable viscosity,
and a variable relationship with
shear stress
Non-Newtonian Fluid
Deformation is not only a shear-induced phenomenon. If the stress is applied
normally and uniformly over all boundaries, then fluids, like solids, decrease in volume. This decrease in volume yields a proportionate increase in density.
COMPRESSIBILITY
______________ a property confined to a free surface and therefore not applicable to
gases, is derived from unbalanced intermolecular forces near the surface of a liquid.
This may be expressed as the work necessary to increase the surface by unit area.
Although not normally important, it can become so if the free surface is present
in a passage of small-diameter orifice or tube.
SURFACE TENSION
FLUIDS AT REST: HYDROSTATICS. For a fluid at rest, the force balance yields to:
Hydrostatic Equation
FLUIDS IN MOTION: At points along a horizontal streamline, higher pressure regions have lower fluid
speed and lower pressure regions have higher fluid speed.
The Bernoulli Equation
Used for measurements and flow
type determinations
The Reynolds Number
Reynolds for laminar flow
< 2000
Reynolds for turbulent flow
> 4000
Flow meters used for flow measurements in pipes containing steam. Used for flow testing purposes in production lines.
Orifice meter
Flow meters used in on-line installations. Used for flow measurement of gases.
Venturi meter
Flow meters used for flow measurements for a single point only.
Pitot tube
Flow meters used in bulk drugs and chemical industries. Used in fermentation systems for air control.
Rotameter
Valves used for isolation.
Gate Valve
Ball Valve
Diaphragm Valve
Valves used for control.
Globe Valve
Ball Valve
Butterfly Valve
Valves used for prevention of flow reversal.
Check Valve
Valves used for flow diversion.
Ball Valve
Plug Valve
Angle Valve
Pumps where energy is continuously applied to increase the fluid velocities
within the system.
Dynamic pumps
Pumps where energy is periodically applied unlike the dynamic pumps
Positive displacement pumps
Effective viscosity range of centrifugal versus positive displacement pumps
C: Efficiency decreases with increasing viscosity (max 200 cP)
PD: Efficiency increases with increasing viscosity
Pressure tolerance of centrifugal versus positive displacement pumps
C: Flow varies with changing pressure while efficiency decreases at both higher and lower pressures
PD: Flow insensitive to changing pressure but efficiency increases with increasing pressure
Priming of centrifugal versus positive displacement pumps
C: Required
PD: Not required
Flow at constant pressure of centrifugal versus positive displacement pumps
C: Constant
PD: Pulsing
Shearing (separation of emulsions, slurries, biologican fluids, food stuff) of centrifugal versus positive displacement pumps
C: High speed motor damages shear-sensitive mediums
PD: Low internal velocity ideal for pumping shear sensitive fluids
Pumps used for injection of polymerization inhibitors and in high pressure systems
Reciprocating pumps
Reciprocating pumps used in peristaltic and HPLC pumps and for spray systems in sugar coating and film coating operations
Piston pump
Reciprocating pumps used in transporting liquid containing solids, while hazardous, toxic, and corrosive liquids can also be handled
Diaphragm pump
Reciprocating pumps used for handling liquids at high pressure, used for transport viscous liquid and liquid contain suspended liquids
Plunger pump
Most used pump in the industry due to it being a low maintenance and high
efficiency pump
Rotary pumps
Rotary pump used for handling viscous or heavy liquid like vegetable oil, animal oil, waxes, used in aqueous film coating
Gear pump
Rotary (centrifugal) pump used for viscous liquid
Volute pump
Rotary (centrifugal) pump used for non-viscous and non-corrosive liquids
Turbine pump
Rotary (centrifugal) pump used for handling organic solvents
Deep well pump
Pumps used for pumping emulsions and creams, parenteral, in blood pumps for operations
Peristaltic pumps
Transfer of heat by means of molecular
excitement within a material without bulk motion of the matter.
Conduction
Law of conduction
Fourier’s law
The transfer of heat between two bodies by currents of moving gas or fluid.
Convection
Convection where Fluid flow is induced by an external force
Forced or Assisted Convection
Convection where Flow is caused by density differences cause by
temperature variations
Natural Convection
Heat transfer process by which the thermal energy is exchanged between two surfaces obeying the laws of electromagnetics
Radiation
Law of radiation
Stefan-Boltzmann law
Value of Stefan-Boltzmann constant
5.6073x10^-8 watt/m^2/K^4
_________ is conceptually and mathematically analogous to heat transfer. In most cases, unit operations and processes are diffusion limited.
MASS TRANSFER
Describes the movement of molecules from a higher concentration to a lower
concentration
Fick’s Law of Diffusion
FILTRATION
The process of separation of solids from a fluid by passing through a porous medium that retain the solids but allows the fluid to pass through. The liquid which has passed through the filter is called the filtrate.
The suspension of solid and liquid is
known as the _____.
slurry
The porous medium is known as the ______.
filter medium
The accumulation of solids on the filter is referred to as the _________.
filter cake
Factors affecting filtration:
- Fluid properties (density, viscosity, corrosiveness)
- Solid properties (particle shape, particle size, particle distribution,
compressibility) - Proportion of solids in the slurry
- Filtration objectives (do we collect the solid, liquid, or both?)
- Is washing necessary for the solids?
Flow of fluids through porous media which states that the rate of movement of water through porous media is
proportional to the hydraulic gradient.
Darcy’s law
The permeability coefficient, k, is a factor of the _________ and its _________.
bed porosity; specific surface area
___________ employing thick, granular beds are widely used in municipal water
filtration.
Gravity filters
Gravity filters operate at low pressures, usually less than _______, which gives low
rates of filtration unless very large areas are used. Their use in pharmaceuticals is very limited.
1.03x104 N/m2
_____ operate at higher pressure
differentials than gravity filters.
Vacuum filters
The vacuum filter pressure is limited naturally to about
________, which confines their use to the
deposition of fairly thin cakes of freely filtering materials.
8.27x104 N/m2
Despite this limitation, the principle of vacuum filters has been
successfully applied to _______ and
___________ cake filtration.
continuous; completely automatic
_____________ filters and _________ filters are most extensively used in the industry.
Rotary vacuum; leaf
_______ filters are used for slurries
requiring high pressure differentials
(i.e. low cake permeability). They may also be used when the
scale of the operation does not justify
the installation of continuous rotary
filters.
Pressure