MASTER PHYSICS

INDUSTRIAL PAINT ( components,types,applications)

2020-04-15T10:32:00.000-07:00

INDUSTRIAL PAINTS

Paints are colloidal solution composed of pigment (coloured material) and solvent to be applied on different surfaces for different purposes.

Apart from colouring, paints are used for many different purposes.

Different paints have different characteristic properties depending on the pigment, solvent and other components used in it.

PAINT

COMPONENTS OF PAINT

PIGMENT

Pigments are fine insoluble particles that impart colour to paint. Pigment appears coloured because it absorbs and reflects certain wavelengths of the visible light. The wavelength of light it reflects is the colour of the pigment. The wavelength of light that is reflected by pigment depends on the particle size of pigment.

pigments

SOLVENT

Solvent is used to spread the paint on the surface on which it is to be applied. When the paint is applied on a surface the solvent vaporizes and the pigment settles forming a film of paint on the surface.

BINDER

Binder holds the particles of pigment together in a paint .It is one of the major component of the paint which keeps the pigment in place after the paint dries.

ADDITIVES

Additives are added in paint to improve the storing properties of the paint, to stabilize pigment particles, to improve weather resistance.

COMPOSITION

Pigment – 25%

Solvent – 40%

Binder – 30%

Additives – 5%

VISCOSITY OF PAINTS

It is thickness of the paints and is the ability to resist spreading. It is inversely proportional to the amount of solvent used. Viscosity is necessary to provide consistent results and acceptable brushing and spraying.

brushing

TYPES OF PAINTS

ALKYD PAINTS

These are also called oil based paints. These paints provide a high gloss and a durable finish. It is the most suitable paint for furniture. It also has some negative points which includes yellowing with age. Yellowing is accelerated in absence of light.

ACRYLIC PAINTS

These are fast drying paints which are soluble in water but become resistant to water when they become dry. These are widely used for painting.

ACRYLIC COLOURS

EPOXY PAINTS

These are used to create tough solvent resistant coat. These are commonly used to protect heavily trafficked areas. It can be applied to concrete floors to provide a durable , high performance surface.

EPOXY PAINT

SOMEOF THE BASIC USES OF PAINTS

Paints are used to protect all sort of metal objects from the effects of sun and water.

Many paints are used as heat resistants in hot and dry regions to prevent the conduction of heat in various structures.

Paint is also applied on furniture to prevent the seepage of water into it.

Paints (epoxy paints) are also used in making surfaces smooth.

Many anti-bacterial paints have been discovered to improve hygiene

REVOLVER (firing mechanism and important components)

2020-04-13T05:16:00.005-07:00

REVOLVER

MAIN PARTS OF REVOLVER

TRIGGER

It is a small lever which is pressed to start the fire mechanism in the gun so that the bullet can be fired

HAMMER

Hammer is the part of fire arm which strikes the firing pin when the trigger is pressed. It passes the mechanical energy from tigger to the firing pin.

FIRING PIN

It is a sharp pointed pin like structure and a spring is wound around it .It impacts the base of the cartridge which contains the propellant.

FIRING PIN

CYLINDER

A cylinder has multiple chambers (6 to 8). It is a rotating part of a revolver. It revolves around a central axis to bring each chamber in alignment with gun barrel.

CYLINDER

GUN BARREL

It is a straight tube through which the bullet shoots off the gun .The inner side of the barrel looks like a spiral shape, it is called rifling .It provides accuracy(by spinning bullet).

GUN BARREL

ANATOMY OF CARTRIDGE

PRIMER

Primer is the base of the cartridge .Firing pin impacts the primer to ignite propellant.

PROPELLANT

Commonly known as gun powder, propellant is important component of firing mechanism .It ignites giving rise to hot gases firing the bullet.

BULLET

It is a component of firearm ammunition that is expelled from the gun barrel. Bullets are made up of variety of materials such as steel, copper, rubber.

CARTRIDGE

FIRING MECHANISM

When trigger is pressed, hammer acts on firing pin transferring energy from trigger to firing pin.

The pointed firing pin hits the primer (base of cartridge) igniting the propellant.

The propellant burns and expands into hot gases. These hot gases push the bullet into the gun barrel (from chamber)

When bullet passes through the gun barrel it acquires a spin which provides it accuracy.

detailed mechanism

RECOIL FORCE

When the bullet shots off from the gun a recoil force is experienced which can be explained through NEWTON’S third law

EVERY ACTION HAS AN EQUAL AND OPPOSITE REACTION.

ENGINE (basic mechanism and importanat components)

2020-04-11T09:16:00.002-07:00

CAR ENGINE

Piston and crankshaft

Engines have Pistons that move up and down inside metal tubes called cylinders.

What powers does Pistons up and down a thousands of tiny controlled explosions occurring each minute created by mixing fuel with oxygen and igniting the mixture

Explosions produce pressure which interns pushes the Piston down this gives rise to rotary motion of the piston

When the Piston again comes up another explosion occurs which pushes the Piston down again
This gives rise to continuous rotary motion of the piston

Most of the automobile engines have four, six or eight Pistons

All the Pistons are attached to a crankshaft it transforms the rotary motion of piston so that it can be used to turn wheels and displace the automobile.

PISTON

CRANKSHAFT

INTERNAL COMBUSTION

There are two main components of this system

SPARK PLUG
FUEL INJECTOR

Fuel injector injects mixture of oxygen and fuel each time the piston comes up

The spark plug ignites the mixture of fuel and oxygen the hot gases and pressure push the Piston down empowering the engine

The principle behind continuous internal combustion engine : if you put a tiny amount of high energy density fuel in a small enclosed space and ignited an incredible amount of energy is released in the form of expanding gas

The amount of mixture injected by fuel injector can be regulated by throttle which Indian can regulate the speed of automobile

FUEL INJECTOR

SPARK PLUG

CONVERSION OF ENERGY

Chemical energy of fuel is converted into mechanical energy of crankshaft (later axle)

DISPLACEMENT

Crankshaft is attached to axle (when car is in gear).

Axle is a shaft that connects centres of the wheels

Rotating crankshaft rotates Excel which inturn rotates wheels to displace the automobile

ENGINE

ELECTRIC MOTOR DC (detailed mechanism and principle)

2020-04-10T05:06:00.004-07:00

ELECTRIC MOTOR

Principle of DC motor

• When a rectangular coil is arranged in a uniform magnetic field, and a current is passed through it ,then it rotates continuously in the field

• ELECTRIC energy is converted into mechanical energy

Parts of ELECTRIC motor

1 Armature
2 Horse shoe magnet
3 Commutator
4 Battery
5 Brushes

Working of DC motor

1. : consider the coil horizontal, in the Plane of the paper
- considering C1 in the contact with brush X
- considering C2 is in the contact with brush Y
- current flows in the coil along ABCD

A current in the coil, set support magnetic field at right angles to the plane of the coil and hence at the right angles to the magnetic field of the permanent magnet this magnetic couple acts on the coil which turns it in the clockwise direction (Flemming's left hand rule)

2.figure 2: does end of the crisis of the plane of the paper and and CD goes down the plane of the paper turns through 90 degree at this moment the magnetic field of the coil becomes parallel to the magnetic field of the permanent magnet
Now X and Y of the brush loose contact with the split ring and the current in the coil is cut off however the call does not stop but continues to rotate due to the inertia of motion until it covers A rotation of 180 degree

3. in the 180 degree position the sides AB and CD are interchanged as a result the commutative ring C1 is now in contact with brush Y and commentator ring C2 is in contact with brush X there for the current continues to flow in the anticlockwise direction in a coil

4. the call turns to an angle of 270 degree in this position once again the brushes and the split rings loose contact and no magnetic couple acts on the coil due to the current cut off.
The coil has a tendency to stop but due to inertia of motion continues to rotate till it covers 360 degree

WAYS TO INCREASE SPEED OF ROTATION

1. By increasing the number of turns in coil

2. By increasing the area of cross section of coil

3. By increasing the strength of radial magnetic field

4. By increasing the current flowing in the coil

5. By laminating soft iron

6. Buy winding number of coils of many turns on the same soft iron core at an angle of few degrees of each other

USES OF MOTORS

1 FANS

2 ELECTRIC LOCOMOTIVES

3 TRAMCARS

4 REFRIGERATORS

5 TROLLEY-BUSES