Rotary Liquid Seal ring type Air compressor

Rotary Liquid Seal ring type Air compressor has forward inclined, open impeller, in an oblong cavity filled with liquid. As the impellerrotates, the centrifugal force causes the seal liquid to collect at the outer edge ofthe oblong cavity. Due to the oblong configuration of the compressor case, large longitudinal cells are created and reduced to smaller ones. The suction port is positioned where the longitudinal cells are the largest, and for the discharge port, where they are smallest, thus causing the vapor within the cell to compress as the rotor rotates. The rotary liquid seal compressor is frequently used in specialized applications for the compression of extremely corrosive and exothermic gasses and is commonly used in commercial nuclear plants as a means of establishing initial condenser vacuum.

Rotary Lobe type Air Compressor

Rotary Lobe type Air Compressor has two mating lobe-type rotors mounted in a case. The lobes are gear driven at close clearance, but without metal-to-metal contact. The suction to the unit is located where the cavity made by the lobes is largest. As the lobes rotate, the cavity size is reduced, causingcompression of the vapor within. The compression continues until the discharge port is reached, at which point the vapor exits the compressor at a higher pressure.

Rotary slide vane type Air Compressor

Rotary slide vane type Air Compressor has longitudinal vanes, sliding radially in a slotted rotor mounted eccentrically in a cylinder. The centrifugal force carries the sliding vanes against the cylindrical case with the vanes forming a number of individual longitudinal cells in the eccentric annulus between the case and rotor. The suction port is located where the longitudinal cells are largest. The size of each cell is reduced by the eccentricity of the rotor as the vanes approach the discharge port, thus compressing the air.

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.

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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.


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