Materials in construction

3 Type of factors. 1. Chemical factors 2. Physical factors 3. Economical factors

1. Contamination of the product by material of plant lead to instability, decomposition and physiological effect.

E.g. presence of traces of heavy metal decompose penicillin.

Stability of vitamins decrease in presence of metallic ions (Cu++, Co++, Ni++).

The color of esters will change to pale yellow in the presence of iron impurities.

Esters should be processed in S.S.

2.The effect on the material of plant by drugs and chemicals.

Acids, Alkalis and Oxidizing agent and tannins may affect the material of construction.

Allows and Plastic have a corrosion resistant properties.

1. Adequate Mechanical Strength. 2. Erosion 3. Weight 4. Ease of fabrication 5. Thermal Expansion 6. Thermal Conductivity 7. Cleansing 8. Sterilization 9. Transparency

Material of plant construction

Ferrous

Non-Metals

CastIron

SteelCarbon

StainlessSteel

Inorganic

Glass

Organic

Non-FerrousMetals

Aluminum

Lead

Rubber Plastic

Widely used bcz of its mechanical strength, abundant availability and lower cost.

Varieties of iron are 1. Cast Iron 2. Carbon Steel 3. Stainless steel

Cast iron consist of iron with a proportion of carbon (beyond 1.5 %).

The properties of iron depends on the amt of carbon present.

Cast iron is abundantly available, inexpensive.

Variety of Carbon Composition AdvantagesAllow

It is an allow of iron. It contains chromium and nickel, which makes the

steel corrosion resistant. S.S. is stabilized by the addition of titanium, or

tantalum. Minor amt of other elements such as copper,

molybdenum, & selenium are added. S.S has the advantages of ease of fabrication. Properties of S.S. 1. Heat resistant 2. Corrosion Resistant 3. Ease of fabrication. 4. Tensile strength 5. Cleaning and Sterilization.

It is cheap, light in weight and offer good mechanical strength.

Al. equipment can be easily fabricated.

Al. can be strengthened by cold working.

Number of modifications of Al are available.

Al is non toxic to micro-organism.

It has the lowest cost. Used as collapsible tube material particularly for non-food products such as adhesives, inks, paints and lubricants.

Lead tubes with internal linings are used for fluoride tooth-paste.

Lead chamber process is used in the manufacture of sulphuric acid.

Acid lead and copper leads are used in chemical industries.

Some metals are added to lead for altering properties.

Silver and Copper: Improve corrosion resistant. Improve creep and fatigue resistant. Antimony, Tin, Arsenic: Hardens, steel melting point is low. Lead lined steel structures are used for the

constructions of pipes, valves, vessels designed for operations at high temp, fluctuating temp or vacuum.

The glass that is prepared by silicon dioxide alone is the most resistant, but relatively brittle.

It can be melted and moulded at high temp. To modify the physicochemical properties cations

such as sodium, potassium, calcium, magnesium, aluminum, boron, iron etc are added.

Glass containers used in pharmaceutical industries are classified in four groups, class I , class ii, class iii, class iv.

Most of the alkali oxides such as Na2O, K2O. Mgo and Cao enter the spaces within the structures and reduce the strength of inter-atomic forces between silicon and oxygen.

The oxide decrease the melting point of glass and are comparatively free to migrate.

This behavior cause number of problems like:

Oxides leach in to the solution, raise the pH, hydrolyze or catalyze chemical reactions.

Some times glass flakes are formed in the solution.

TypesGeneral

DescriptionProperties Uses

Used as such as a lining material for the construction of plants.

Type of rubber 1. Natural Rubber 2. Soft rubber. 3. Hard Rubber 4. Synthetic Rubber.

Five type of Synthetic Rubber

1. Neoprene 2. Nitrile Rubber 3. Butyl Rubber 4. Silicon Rubber 5. Polyisoprene

Light in wt so transportation is easy and cheap. Available in variety of shape and easily

fabricated. Used for storing number of materials. In machines, plastic material is preferred

wherever moving parts are present indicating that it offers less resistant.

Plastics are synthetic resins containing long chains of atoms linked to form giant or macromolecules (polymer).

They have high molecular weight.

Rigid materials Flexible materials Metallic surfaces Plastic cements Special case plastics