Types Rotary Compressors

Rotary Compressors
The rotary compressor is adaptable to direct drive by induction motors or multicylinder gasoline or diesel engines. The units are compact, relatively inexpensive, and require a minimum of operating attention and maintenance. They occupy a fraction of the space and weight of a reciprocating machine of equivalent capacity.
Rotary compressor units are classified into three general groups
Slide vane-type
Lobe-type
Liquid seal ring-type.

Types of Air Compressor

Air compressors of various designs are used widely throughout DOE facilities in numerous applications. Compressed air has numerous uses throughout a facility including the operation of equipment and portable tools.
Three types of designs
1. reciprocating
2. rotary
3. centrifugal air compressors.

Working of Centrifugal Compressor

Introduction

Air compressors of various designs are used widely throughout DOE facilities in numerous applications. Compressed air has numerous uses throughout a facility including the operation of equipment and portable tools. Three types of designs include reciprocating, rotary, and centrifugal air compressors.

Centrifugal Compressors

The centrifugal compressor, originallybuilt to handle only large volumes of lowpressure gas and air (maximum of 40psig), has been developed to enable it tomove large volumes of gas with dischargepressures up to 3,500 psig. However,centrifugal compressors are now mostfrequently used for medium volume andmedium pressure air delivery. Oneadvantage of a centrifugal pump is thesmooth discharge of the compressed air.The centrifugal force utilized by thecentrifugal compressor is the same forceutilized by the centrifugal pump. The airparticles enter the eye of the impeller,designated D in Figure 6. As the impeller rotates, air is thrown against the casing of the compressor. The airbecomes compressed as more and more air is thrown out to the casing by the impeller blades.The air is pushed along the path designated A, B, and C in Figure 6. The pressure of the air is increased as it is pushed along this path. Note in Figure 6 that the impeller blades curve forward, which is opposite to the backward curve used in typical centrifugal liquid pumps.Centrifugal compressors can use a variety of blade orientation including both forward and backward curves as well as other designs.There may be several stages to a centrifugal air compressor, as in the centrifugal pump, and the result would be the same; a higher pressure would be produced. The air compressor is used to create compressed or high pressure air for a variety of uses.Some of its uses are pneumatic control devices, pneumatic sensors, pneumatic valve operators, pneumatic motors, and starting air for diesel engines.

Please comment on this Post

Grain Boundary Strengthening

Grain Boundary Strengthening in Strenghtening Process
Decreasing/Finer grain size will increase the yield stress.

The grain size indicates two conditions: The distance for the dislocations have to move to form grain boundary pile-ups and the number of dislocations involved. Having finer grain size, the mobility of the dislocations is harder to move from one grain to another for plastic deformation. In other words, finer grain will impede the dislocations. This will give rise to the strength of the material. However, the grain size cannot be too small (around below 10 nm). This will lead to grain-boundary sliding. The grain boundaries tend to slide and difficult to fit the dislocations in the grain. Thus, less stress required to move them. The equation to this mechanism is The Hall-Petch Equation which states an increase in yield stress is related to a decrease in diameter of the average grain.


"Dont forget to post a comment, it is the feed back system for any Blogger"

Definition of Precipitation Hardening

What is Precipitation Hardening?
It is a strengthening Process. it is Heat Treatment Process.
"Changes in solid solubility with temperature to produce fine particles of an impurity phase will increase the strength."

now, lets find out the process detailly........
This heat treatment process involves the changes in solid solubility with respect to temperature to produce fine particles of an impurity phase. This condition will obstruct the dislocation and the crystalline lattice and thus, increase the strength of the material. This heat treatment involves precipitation of impurity particles to have a strengthen material. These impurity particles are considered as second phase particles. The presence of these precipitates of second phase particles will cause lattice distortion because of the different is size comparable to the host particles. This distortion will then impede the dislocation which leads to the hardening of materials.

Solid Solution Strengthening or Alloying

what is Solid Solution Strengthening?
It is a strengthening Process.
Adding alloying element will increase the strength of the material.

Adding atoms of alloying element into the crystalline lattice of base metal, the alloying element will diffuse to a matrix solid solution. These solute atoms will cause lattice distortions which then will obstruct dislocation motion, and thus will increase the yield stress of the material. There are two types of this mechanism: Substitutional Solid Solution and Interstitial Solid Solution. The former type involves the solute (alloy) atoms which are larger compared to the solvent (base) atoms being added into crystalline lattice of base metal. They must be the same crystal structure. The instance is Copper-Nickel in FCC structure. While, the latter type involves the solute atoms are smaller than the solvent atoms. The example is the carbon in iron.

Definition of Work Hardening

What is Work Hardening
Increasing the dislocation density will increase the yield strength.

Work Hardening is a difficult process to understand. but, once you understand the process, you will never forget.

Work hardening is a process when the metal is strained beyond its original yield point. As the material is filled up with more dislocations (increasing dislocation density), more dislocations are prevented to develop more dislocation-formation. This resistance is called nucleating and thus, the resistance to plastic deformation. Therefore, the material has been strengthened. However, the dislocation density cannot be increased to an infinitely high value as the crystalline structure will disappear. Usually, work hardening is done to a reasonably high melting point material by using cold rolling or cold drawing.