Cam and Follower Mechanism And their Types

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Cam and Follower Mechanism is a widely used method of motion transformation. Cam follower is also known as 'Track Follower'.

Cam is a rotating element Which provides an oscillation or reciprocatory motion to another part connected with the cam. Another part associated with the cam is called 'follower'.


cam-fololwer-mechanism-types
Cam And Follower: Source




The cam rotates about an axis and the follower is attached to it with a point contact. Basically, the cam and the follower makes a higher pair together.

To make a set of cam and follower first we need to determine the required motion of the follower. When we know the path of the follower, then the shape of the cam will be designed. The design g the cam would be based on the length of the path which follower has to proceed and also to the speed of the movement. The rotation of the cam would be at uniform speed.

The cam and follower mechanism are widely used in automobile industry. For example, inlet and the outlet port of i.c. engines, feed mechanism in the lathe machine etc are the mechanism of cam and follower. This mechanism is very important in modern day engineering to incorporate a system with controlled movement. 

Types of Cam and Follower

The classification of the cam and follower is based on many factors. these factors and the types of the cam follower is described below

Types of Cams

the types of cams are generally based on their shapes.
  1. Cylindrical Cams
  2. Disc-shaped or Radial cams
  3. Spherical Cams

Types of Followers

Followers are classified as per the factors are given below

According to surface contact

  1. Knife Edge follower
  2. Flat faced follower
  3. Roller Follower
  4. Spherical Follwer

According to types of motion of the Follower

  1. Oscillatory Motion Follower
  2. Reciprocating follower

Based on the path of motion of the follower

  1. Radial Follower
  2. Off-Set Follower

Advantages and Disadvantages of Cam and Follower

It is an accurate design mechanism with a higher standard method of motion transformation.

the elements used in the mechanism are usually durable and long lasting.

Load Carrying capacity of cam and follower is excellent.

Limitation

The higher accuracy of machine element is required. Especially for rotary motion is required as input to the mechanism

Applications of Cam Follower mechanism

Cam and follower mechanism mostly used in the Automobile vehicles. The inlet and the exhaust valve is controlled by cam and follower in the I.C. engine.

A very simple use of cam follower can be seen in wall clocks

In the textile industries, this mechanism is used for weaving purpose.

In the automatic lathe machine, It is used in the feed mechanism.

This is a short description of cam and follower. The cam follower Mechanism is a broad topic because of its wide area of applications.


Zeroth Law Of Thermodynamics

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Zeroth law of thermodynamics mainly deals with one of the most important properties of thermodynamic system i.e. temperature.

Temperature is a property which denotes the degree of hotness or coldness of a system or any matter.

Here we are talking about temperature so it is clear that zeroth law of thermodynamics is a law of temperature.

The principle of Temperature Measurement

After the recognition of temperature as a property, the measurement of this property is required. Temperature is not an actual parameter, that is why temperature cannot be measured as its actual value so there are some standards made to define and measure this property.

Some standard temperature are used as consideration to develop these units, such as ice point ( temperature of ice considered to be 0°C, Steam point (temperature of water when steam formation starts is considered to be 100°C)

There are some more fixed temperatures like this referring to which the temperature scales were developed.

Zeroth law of thermodynamics Statement

Zeroth law of thermodynamics states." When two bodies A and B are separately in thermal equilibrium with another body C, then these two bodies A and B will also be in thermal equilibrium."

Zeroth law of thermodynamics
Zeroth law of thermodynamics
The block diagram above shows that the Body A is in equilibrium with body C and body B is also in equilibrium with body C. this will make both A and B in equilibrium. Equilibrium is shown by arrows in the block diagram.

Zeroth law pays a vital role in the temperature measurement and analysis of thermal equilibrium. Various types of Thermometer is developed with the principle of temperature measurement.

Zeroth law of thermodynamics was discovered after the first and second law of thermodynamics. But the law should be placed before the first and second law, that is why it was named Zeroth law of thermodynamics.

Reversible and irreversible process (Reversibility and Irreversibility)

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When a thermodynamic process occurs the change of state will happen. the process will Change from initial state to final state. the change in state in the process occurs in two ways. Here, the thermodynamic properties will undergo some changes to change the state or to complete the process. there are two ways of the thermodynamic process and these are the reversible or irreversible process.

Reversible process or Reversibility

A reversible process is a thermodynamic process which is capable of attaining its initial state by following the same path by which the process reaches to final state of the process from its initial state to complete the process.


Reversible process in thermodynamics
Reversible process
As shown in the graph the initial state of the system is A. when the thermodynamic process changes its state from A to B to complete the process the system will follow the path A-O-B. If the process is reversible then it will have the capability to get its initial state by following the same path B-O-A. this is called reversibility of a thermodynamic process.

The reversible process is not a practical phenomenon because there is always some deviations in the process So it is a theoretical consideration.

Quasi-Static process is an example of reversible process, but one thing should be kept in mind that Quasi-static process is itself an assumption. To understand the reversible process and thermodynamics equilibrium quasi static process it is analyzed.

Irreversible process or Irreversibility

Irreversible process is different from a reversible process. The system will be able to regain its initial state after a process but it has to take a different path than the process is completed previously.

Irreversible process in thermodynamics
Irreversible process
In the graph, an Irreversible process shown. In the system When the state is changed from state A to state B the process is completed. To complete this process the path which is taken is A-O-B. When the system will try to attain its initial state A, it has to follow a different path A-Q-B. this makes this process an Irreversible process and This is called irreversibility of a process.

There is a lot depends on the properties of the system because thermodynamic properties of the system decide reversibility and irreversibility of the thermodynamic process.    

This is a short description of the reversible process and irreversible process. Thermodynamic analysis largely depends on these phenomena. 

Quasi Static Process or Quasi Equilibrium Process in Thermodynamics.

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when a system in which matter in enclosed, undergoes a thermodynamic process, the thermodynamic equilibrium will no longer remain in the system. Although, it is impossible to have a system in thermodynamic equilibrium when it undergoes a process but there is an assumption with some considerations in which a process can be occurred while maintaining system in thermodynamic equilibrium. This process is called Quasi Static process or Quasi Equilibrium Process.

Define Quasi Static 

The words 'Quasi' literally means 'Almost' and "Quasi static" means 'Almost Static'. So the Quasi static process is one which is almost remains in a single state. This process shows very small or infinitesimal deviation from its original state.  due to this negligible change of state the process is seems to be in thermodynamic equilibrium.

Quasi Static process Analysis

In the process a piston-cylinder setup is taken in which gas is filled inside it.
when the heating of the cylinder or container is done the inside gas temperature will increase and the piston will be raised up. here the system will not be in equilibrium.

Quasi Static Process
Quasi Static Process

But if we put Some Weight on the piston such that the height at which piston is raised is covers back by this weight as the piston will go downward due to this weight. when we further heat the cylinder the piston will be raised again so we again put some more weight on it to compensate the raising of the piston. we will do it until the heat is added and we make sure the piston is at its initial position by putting appropriate amount of weight in it.

In this way we will keep the piston at static position and avoid the change of state in the system. the change of state will be infinitesimal

This is a short description about Quasi static or quasi equilibrium process. it is an experimental assumption to show the thermodynamic equilibrium in a system. To maintain thermodynamic equilibrium in a system is a difficult thing. but in this experiment system remains closed to the equilibrium state.

What Is Thermodynamics. Important Terms Related To Thermodynamics ( Path, Process, Properties, State And Cycle)

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Thermodynamics is a part of science which is related to heat, temperature, and energy. It is concerned with various forms of energy and its mutual conversion. The Thermodynamic behavior of different quantities or matter is controlled by 4 laws of thermodynamics. In this universe, there is always a relation between any matter and energy. Thermodynamics is applicable in a wide range of Science, Technology and Engineering world.

The motive of studying thermodynamics is to understand various forms of energy and develop the efficient energy systems.


Important terms related to thermodynamics

There are some important terms related to thermodynamics which is often used during thermodynamic analysis.

Thermodynamic Properties

Properties are the parameters which describe the nature and characteristics of a system. these parameters are used to define the thermodynamic system and its behavior. Some examples of thermodynamic properties are pressure, volume, temperature, viscosity etc.

Properties are categorized into two parts "Intensive properties and extensive properties"

Intensive properties

Intensive properties are those which are independent of the mass of the system in which matter is enclosed. As the properties are independent of mass, the properties will have identical value at every point of the system. Examples of intensive properties are pressure temperature etc.

Extensive properties

Extensive properties are dependable on the mass of the system these properties do not have the same value in the whole system. Examples of these properties are volume, viscosity, energy etc.

Thermodynamic State

State of a system can be defined as a certain position or condition in which properties of the system will have certain quantitative values. These Values defines a specific state. Changing these values will lead to the different state of the system. this change is called 'change of state'.

Thermodynamic Process

Due to the energy and mass transfers from the system and to the system, change of state takes place. This changing of the state is called process. for example, heating of a gas in a vessel can lead to change in pressure and temperature viscosity etc. In such ways, properties of the system can be altered and a thermodynamic process is completed.

Thermodynamic Path

A path is something when the change of state happens repeatedly and series of the process occurs. In the system, this series of process can be traced by
a locii. that locii will be known as Thermodynamic Path.

Thermodynamic cycle

When a system undergoes to several processes but at the last, it gains its initial state from where the sequence of processes started, then the system is said to be completed a cycle. all in all the initial and final state will be same in a cycle. the cycle will have a closed loop path in the thermodynamic system.

Thermodynamic equilibrium

When the system does not undergo in a change of state even when the external efforts are applied, then the system is said to be in Thermodynamic Equilibrium
To get a system in Thermodynamic Equilibrium it should be in equilibrium mechanically, thermally and chemically.

these are some important terms and parameters of thermodynamics. Although, thermodynamics is a broad subject but these terms are very significant. in each and every thermodynamic analysis the terms like path, process, cycle, properties are always used.

System, Surroundings, Boundary and Universe in thermodynamics - types of systems (open, closed, isolated)

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These are some common definitions associated with the basic thermodynamics. every thermodynamic study and analysis is related to these terms. let's get a quick review of these terms.

Thermodynamic System

thermodynamic system is the place which contains a certain quantity of matter in which thermodynamic processes happen and thermodynamic analysis can be carried out. in the system, the matter will consist of certain properties which can be altered by different processes like transfer of mass and energy.

Thermodynamic System

Surroundings 

Everything external to the system i.e. the outside environment is called surrounding to the system.

Boundary of the System

Boundary is something which separates the system and the surroundings. the boundary can be real or imaginary. sometimes a relative boundary is considered so the boundary can be at rest or in a motion.

Universe

The combination of system and surroundings is called Universe i.e. when both system and the surroundings are kept together they can be referred as the universe.

Types of System

there are three types of systems that are recognized-
1. Open System
2. Closed System
3. Isolated System

Open System

Open Systems are those in which both Mass and Energy can be inserted and can be taken out of it. This system is open to any intersection of mass and energy.

Closed System

Closed system is one in which mass remains constant i.e. mass cannot be added or subtracted but energy can be manipulated.

Isolated system

Isolated System is one in which mass and energy both can neither be added nor be subtracted from the system.