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Ch_9_F

P.S.Sona Laxmi Publications PDF

32 A Practical Manual of Pharmaceutical Engineering

EXPERIMENT

9

DETERMINATION OF FLOW

OF FLUID—ROTAMETER

AIM

To determine the flow of fluid through a pipe using Rotameter.

REQUIREMENTS

Rotameter

(1)

Pipe connection

(2)

Measuring cylinder

(1)

Water

PRINCIPLE

Rotameter consists of a tapered glass tube with the smallest diameter at the bottom. The tube contains a freely moving Float/plummet which rests on a stop at the base of the tube. When the fluid is flowing, the float rises until its weight is balanced by the up thrust of the fluid and reaches a position of equilibrium, this position then indicates the rate of flow. Floats can be of many shapes, but spheres and ellipsoids being the most common. The float is shaped so that it rotates axially as the fluid passes. Readings are usually taken from the top of the float.

The rotameter�s operation is based on the variable area principle: Fluid flow raises the float in a tapered tube, increasing the area for passage of the fluid. The greater the flow, the higher the float is raised. The height of the float is directly proportional to the flow rate. With liquids, the float is raised by a combination of the buoyancy of the liquid and the velocity head of the fluid. With gases, buoyancy is negligible, and the float responds to the velocity head alone.

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Ch_19_F

P.S.Sona Laxmi Publications PDF

78 A Practical Manual of Pharmaceutical Engineering simple sedimentation. Separation is happened under gravity depending upon the size as well as the density of the particles. So sedimentation method can be used for determining the size of the particle settled.

Several methods are available based on sedimentation for the size separation and particle size determination. They are hydrometer method, pipette method and balance method. Andreasen apparatus works under the principle of pipette method. The particle size in the sub sieve range may be obtained by sedimentation as expressed in Stoke�s law,

V = h/t =

dsJ 2 ( r s - r0 ) g

18 h 0

� (Eq: 19.1)

Or

@It =

18 h 0 D / ( r s - r 0 ) g J

� (Eq: 19.2)

Where,

V h dst rs, r0 h0

= Rate of settling (m/s)

= Distance of fall within time (t)

= Mean diameter of particle based on the velocity of settling

= Density of particle and water (kg/m3)

= Viscosity of medium (Poise)

The particle diameter corresponding to various time intervals is calculated from Stoke�s law.

The residue or dried sample obtained at a particular time is the weight fraction having particle of size less than that size obtained from Stoke�s law. Hence each sample is therefore called as weight undersize. Add up the successive weight undersize (expressed in %). This is then plotted on log probability scale (log normal) against particle diameter (log scale) and the geometrical mean diameter d�g can be determined from the reference point i.e., 50% on the probability scale and geometrical standard deviation sg can be determined from the slope. The other statistical parameters can be determined from the equations, log dln (Length number mean diameter) log dsn (Surface number mean diameter) log dvn (Volume number mean diameter) log dvs. (Volume surface mean diameter) log dwm (Weight momentum mean diameter)

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Ch_50_F

P.S.Sona Laxmi Publications PDF

194 A Practical Manual of Pharmaceutical Engineering

EXPERIMENT

50

DETERMINATION OF FACTORS

AFFECTING CORROSION RATE—TOTAL

IMMERSION TEST

AIM

To determine the effect of different factors affecting rate of corrosion.

REQUIREMENTS

Metal pieces (iron) diameter 20 mm and thickness of 3 mm

(12)

Beaker

(6)

Round bottom flasks

(6)

Heating mantles

(6)

Glass rods

(6)

Reflux condensers

(6)

Weighing balance

(1)

Weighing Box

(1)

Concentrated solutions of acids

(1 M H2SO4, 1M HCl, 1M NaOH)

PRINCIPLE

Refer the previous experiment.

Corrosion of metals will happen at a rate that varies substantially, depending on the conditions.

Nature of the material or alloy, surface condition/roughness, material, configuration, materialmaterial spacing, composition, moisture, absorptivity, Structure, Nature of any reinforcement,

Temperature, Humidity, Corrosive elements (type, concentration) are some of the factors affecting corrosion rate. Higher levels of corrosion that occur in the presence of moisture and the hostile gas species, such as chlorine, ammonia, sulphur dioxide, hydrogen sulphide and oxides of nitrogen, that are often present in the atmosphere.

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Appdiex_XIV

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Medium 9789383828432

Ch_42_F

P.S.Sona Laxmi Publications PDF

162 A Practical Manual of Pharmaceutical Engineering

EXPERIMENT

42

DETERMINATION OF NUMBER OF

THEORETICAL PLATES—FRACTIONAL

DISTILLATION

AIM

To determine the number of theoretical plates while performing the fractional distillation.

To determine the HETP (Height equivalent to one theoretical plate).

REQUIREMENTS

Fractional distillation assemble

(1)

(Fractionating Column, Round bottom flask, Condenser, adaptor, receiver, thermometer)

Pipes

(2)

Specific gravity bottle

(2)

Heating mantle/ burner

(1)

Tripod stands

(2)

Burette stands

(2)

Conical flask

(1)

Water

Ethanol

PRINCIPLE

Fractional distillation is a process by which components in a chemical mixture are separated according to their difference in the boiling points. Vapors from a boiling solution are passed along a fractionating column. The temperature of the column gradually decreases along its length.

Components with a higher boiling point condense on the column and return to the solution; components with a lower boiling point pass through the column and are collected as fractions.

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