3 Speed Gearbox Mechanism

Gearboxes or also commonly called gear reducers or enclosed speed reducers are used on many electromechanical drive systems. Gearboxes, are essentially multiple open gear sets contained in a housing. The housing supports bearings and shafts, holds in lubricants, and protects the components from surrounding conditions. Gearboxes are available in a wide range of load capacities and speed ratios.

The purpose of a gearbox is to increase or reduce speed. As a result, torque output will be the inverse of the speed function. If the enclosed drive is a speed reducer (speed output is less than speed input), the torque output will increase; if the drive increases speed, the torque output will decrease. Gearbox designs are classified as either bevel designs, where gears are perpendicular to each other, or spur designs, where two gears rotate parallel to each other.

The 3 Speed Gearbox presents the mechanism of a gearbox. Gears of various dimensions are placed along the x and y axis. A motor rotates the central shaft and different arrangements that can be made in the project causes the rotational motion to transfer from one axis to other. The project is mainly made from Mdf, mild steel and Acrylic. The machine can be divided into 4 groups of gears. Each group consists of 4 gears of different dimensions. The machine works in 3 different scenarios.

In scenario 1, the central shaft is held together by a coupler. The rotational motion starts from the motor and transfers to the group 1 gears and from there, with the help of the coupler transfers to group 3 gears. In this scenario, the group 2 & 4 gears are disengaged. In scenario 2, the coupler & the group 4 gears are disengaged. The rotational motion starts from the motor and transfers to group 1 gears and from there via group 2 gears transfers to group 3 gears.

In scenario 3, the coupler & group 2 gears are disengaged. The rotational motion which starts from the motor transfers to group1 gears and from there transfers to group 3 gears via group 4 gears. The transfer of motions between groups of gears is possible due to proper meshing of biggest gears present in group 1 & 3 and smallest gears present in groups 2 & 4

Explain Vapor Absorption System

Vapor Absorption System 

In this system refrigerant is absorbed by an absorbent on low pressure side of the system and rich
solution is pumped up on higher pressure side. Heat is released in absorption and condensation,
which is taken away by cooling water. Refrigerant is separated from absorbent in generator
where heat is supplied by steam or hot water or other heat source. Rich (or strong) solution from
absorber is pumped to generator via a heat exchanger, which serves the purpose of cooling the
weak solution on its return to absorber and heating the strong solution on way to generator. This
saves heat supplied to generator and heat removed in absorber.
Significant features and advantages

1. It is similar to standard vapor compression cycle, but it is heat operated system. Energy
source, other than electricity can be used to operate the system. Compressor is replaced
by an absorber and generator loop.

2. A secondary fluid or crystal called absorbent is used to absorb refrigerant in a vessel
called absorber. A liquid rather than a gaseous substance is pumped from low pressure
side to high pressure side which requires less work. Strong solution from absorber is
pumped to generator, where refrigerant is evaporated from absorbent by supply of
external heat to the system. Refrigerant vapor from generator is passed on to condenser
where it is condensed to liquid by removal of heat by cooling medium (air or water).
Liquid refrigerant is throttled to evaporator pressure and passed to the evaporator, where
it removes the heat from the cooled substance (called load).

3. “Performance factor” (ηp) or “COPabs” (Coefficient of Performance Absorption cycle) is
defined as:

where, qg = heat rate supplied to generator,
and qe = heat rate taken in to evaporator.

In this definition smaller quantity of mechanical work input to pumps is ignored as compared to
large quantity of heat rate sin generator and evaporator. In general, if we take into consideration
the pump work also, then the definition will be as:

[Note: In industrial practice, sometimes it may be expressed in terms of rate of steam supplied to
the system per ton of refrigeration, e.g., 20 kg / hr. ton]
Application:
1. Domestic refrigerator “Electrolux” of “Servel” company.
2. Commercial refrigeration for air conditioning in chiller plant.

Vacuum Refrigeration System

Vacuum Refrigeration System

Steam-Jet Refrigeration System

Ejector Refrigeration System

Water and steam are used as refrigerant in this system. Chilled water at 40C is achieved in the
evaporator which is kept under vacuum. Water vapor from the evaporators is pumped by steam
jet pumps (called as ejectors) to the main condenser, where vapor is condensed under vacuum.
The pressure ratio in ejector system is usually 7 to 8. The resulting water from the condenser is
pumped to atmosphere pressure. Secondary ejectors are used to pump non –condensable gasses
(air) to the atmosphere pressure. The steam used in these secondary ejectors is condensed in
inter- and after-condenses. (Refer to the figure)
Application:
1. This system is suitable for moderate refrigeration temperatures like those in air
conditioning and some industrial processes.
2. This system is economical only for large installations where steam is available for other
processes.

how to find compressor efficiency and power?

Refrigeration Compressor Efficiency

1.Volumetric Efficiency

a) Actual volumetric Efficiency

b) Clearance volumetric efficiency,

2. Compression Efficiency (or Adiabatic Efficiency), 

Mass Flow Rate of Reciprocating Compressor

 

                m=(vdis/vsuc)  x ηv/100 kg/s

Compressor Power

P = m (delta hi) kW

where, delta hi = isentropic work done on compressor per unit mass

Types and classification of Refrigeration Compressors

Types of Refrigeration Compressors

1. Reciprocating Compressors:
a) Single cylinder
b) Multi-cylinder
i. V-type
ii. W-type
iii. Radial type

2. Rotary Compressors:
a) Vane type
i. Roller type
ii. Multi-vane type (two-vane; four-vane)
b) Screw type
c) Scroll type
d) Centrifugal type

Classification of Refrigeration Compressors

1. Hermetic
2. Semi-hermetic
3. Open

Vapor compression Cycle:

In this cycle vapor is compressed then condensed to a liquid following which the pressure is

dropped so that fluid can evaporate at a low pressure.

1. Single stage cycle
2. Two stage/multi stage cycle
3. Cascade cycle

For detail of above thee systems of vapor compression see the class notes of chapter10 of
textbook by Stoecker and Jones, 2nd ed.

The Carnot Refrigeration Cycle:

The Carnot Refrigeration Cycle:

It is the most efficient cycle and valid for gases as wall a vapors i.e. It can also be realized in wet
region of the p-h or T-S diagram. These cycles approach external reversibility as T → 0. i.e
heat transfer with environment takes place with minimum possible temperature difference.
(Refer to the figure T-S diagram)
Source of irreversible losses (loss of efficiency)
· P in suction and discharge valves
· Re-expansion of gas in clearance volume
· Leakages past rings
· Leakages through discharge and suction valves
· Cylinder heating of the suction gas

Types of Refrigeration Systems:

Types of Refrigeration Systems:

1. Reversed Carnot Cycle (Ideal Refrigeration Cycle)
2. Vapor Compression Cycle
a. Single stage compression
b. Multistage compression
c. Cascade (Binary Vapor) cycle
3. Steam Jet (Or Vacuum) System
4. Vapor Absorption Cycle
5. Air Refrigeration Cycle. (Gas Refrigeration Cycle, Reversed Brayton cycle or Reversed
Gas Turbine Cycle)
6. Thermoelectric Cooling (Peltier Effect)
7. Vortex Tube Cooling
a. Counter flow vortex tube.
b. Uniflow vortex tube.
8. Cryogenic Systems
a. Linde Liquefier
b. Claude Liquefier
9. Magnetic Cooling Near Absolute Zero Temperature

Defination Milling Machine its Types and it uses

DEFINATION OF MILLING MACHINE:

Milling machine is a process that can perform in which cutting tool remove material from the workpices present in the direction of angle of the tool axies with tyhe help of milling machine many peration canperformed by small object top the large ones.

Milling

Introduction

Milling is the process of machining flat, curved, or irregular surfaces by feeding the work piece against a rotating cutter containing a number of cutting edges. The usual Mill consists basically of a motor driven spindle, which mounts and revolves the milling cutter, and a reciprocating adjustable worktable, which mounts and feeds the work piece.

Milling machines are basically classified as vertical or horizontal. These machines are also classified as knee-type, ram-type, manufacturing or bed type, and planer-type. Most milling machines have self-contained electric drive motors, coolant systems, variable spindle speeds, and power-operated table feeds 


Milling Machine Play Role in Manufacturing Technology

Milling is a process of producing flat and complex shapes with the use of multi-tooth cutting tool, which is called a milling cutter and the cutting edges are called teeth.

The axis of rotation of the cutting tool is perpendicular to the direction of feed, either parallel or perpendicular to the machined surface. The machine tool that traditionally performs this operation is called milling machine.

Milling is an interrupted cutting operation in which the teeth of the milling cutter enter and exit the work during each revolution. This interrupted cutting action subjects the teeth to a cycle of impact force and thermal shock on every rotation. The tool material and cutter geometry must be designed to withstand these conditions. Cutting fluids are essential for most milling operations.

Types of milling

There are two basic types of milling

Down (climb) milling, when the cutter rotation is in the same direction as the motion of the work piece being fed.

up (conventional) milling, in which the work piece is moving towards the cutter, opposing the cutter direction of rotation

Comparison of Up and Down Milling

Down milling, the cutting force is directed into the work table, which allows thinner work parts to be machined. Better surface finish is obtained but the stress load on the teeth is abrupt, which may damage the cutter.

Up milling, the cutting force tends to lift the work piece. The work conditions for the cutter are more favorable. Because the cutter does not start to cut when it makes contact (cutting at zero cut is impossible), the surface has a natural waviness

Milling Operations

Milling of Flat Surfaces

Peripheral Milling

In peripheral milling, also called plain milling, the axis of the cutter is parallel to the surface being machined, and the operation is performed by cutting edges on the outside periphery of the cutter. The primary motion is the rotation of the cutter. The feed is imparted to the work piece.

In peripheral milling the axis of the cutter rotation is parallel to the work surface to be machined

Types of Peripheral Milling

Slab milling

The basic form of peripheral milling in which the cutter width extends beyond the work piece on both sides

Slotting

Slotting, also called slot milling, in which the width of the cutter, usually called slotter, is less than the work piece width.

The slotter has teeth on the periphery and over the both end faces. When only the one-side face teeth are engaged, the operations is known as the side milling, in which the cutter machines the side of the 

Straddle milling

Straddle milling, which is the same as side milling where cutting takes place on both sides of the work.

In straddle milling, two slotters mounted on an arbor work together;

When the slotter is very thin, the operation called slitting can be used to mill narrow slots (slits) or to cut a work part in two.

The slitting cutter (slitter) is narrower than the slotter and has teeth only on the periphery.

IMPOSSIBLE AND LAW OF COMPLEMENT THEOREM.

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WHAT IS PROBABILITY AND THEIR TYPES

PROBABILITY:

               In case of engineering statics we take a probability definition for this type.

                             

        "probability is define as predict to happening something"




for  example :IT WILL RAIN TODAY

probability are generally two types :

1. experimental
2. theoretical

here we discussed today experimentally probability in very briefly so please read full to clear your concept.


EXPERIMENTAL:

                                   An operation which can produced same well -defined outcomes is called experiment.


RANDOM EXPERIMENT:


                                   An experiment in which all possible outcomes at known and the exact output presided in advance is called random experiment.



SAMPLE SPACE:


                                   When we perform an experiment then the set S of all possible outcomes is called sample space.e.g

                            S={H,T}



EVENT:


              Any subset of a sample space is called an event


                               P(E)=NUMBER OF FAVORABLE OUTCOMES  /  TOTAL NUMBER OF POSSIBLE OUTCOMES



 EQUALLY LIKE EVENTS:

             
               Two events A and B are said to be equally likely events when one events is has likely to occur as the other.



MUTUALLY EXCLUSIVE EVENTS:


             Two events A and B of a single experiment are said to be mutually exclusive events or disjoints sets if and if only if they can not both occur at the same time that is They have no points in common.


               AnB=O



EXHAUSTIVE EVENTS:

                       
               Is that their union must cover all the events with in the bentire sample space .For example events A and B are said to be collectively exhaust it


             AuB=S










IF YOU GAINING FURTHER CONCEPTS SO PLEASE WATCHING YOU TUBE VIDEO






YOUTUBE WATCHING VEDIO:



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MECHANICAL ENGINNERING.

                                           

    WHAT DO FOR MECHANICAL POURPOSE

Mechanical  engineering is the branch of engineering and it is very interesting field about machines works .  In this field we can learn   drawing,manufacturing process, engines and every thing releated with machines discussed in mechanical engineering e.t.c. 

WHAT IS THE FUTURE OF MECHANICAL ENGINEERING......

   The future of mechanical engineering is very bright .there is alot of industry which applies mechanical work.like that

1. manufacturing process
2. maintenance
3. robt
4. atomobile
5. chemical industry
6. electrical industry

MANUFACTURING PROCESS

Manufacturing processs is a most important part of industriallife the defination of manufacturing process is "manufacturingis a process in which raw material convert to finish product.

in modern century the manufacturing methods are modern . they convert raw materil to finishes product very better accuiracy by the helping of modern machines and technology so the future of manufacturing process is very bright . 

every industry or every work are depent on manufacturing in Engineering field or etc.

because manufacturing is the way of discipline in which can convert raw material to finish product .

modern manufacturing pics i can download for internet for giving better concept.

here you can see the future of manufacturing process is very beautiful in mechanical engineering.

so this the best example of future of mechanical engineering...

Thanks God.

Hi, my Name is Hamza and i am thank full to God for giving me beautiful life