COMPERSSORS TECHNOLOGY

COMPERSSORS TECHNOLOGY: 

COMPERSSORS TECHNOLOGY INTRODUCION COMPERSSORS USES ADVANTAGES AND DISADVANTAGES OF COMPERSSORS GLOSSARY OF AIR COMPERSSRS CLASSIFICATION OF COMPERSSORS PANVEL TRAINING CENTRE : Tuesday, August 23, 2011

INTRODUCTION: 

INTRODUCTION COMPRESSORS ARE USED TO INCREASE THE PRESSURE OF GASES. COMPRESSORS ARE REQUIRED FOR SEVERAL PLANT OPERATION AND PROCESSES. AIR COMPRESSOR RATED CAPACITY IS DETERMAINED BY THE COMP. FLOW RATE & DIS. PRES. UNDER STANDERED CONDITION THE STANDERED CONDITION 20C,10013 BAR AND 36% HUMIDITY THE UNIT OF FLOW RATE IS M3/MIN DIS PRES.KPa THERE ARE TWO MAIN TYPES: DYNAMIC DISPLACEMENT

USES OF COMPRESSED AIR : 

USES OF COMPRESSED AIR Some of the uses of compressed air are listed below :- - Motive power for grinding and sanding tools, drills, and wrenches, riveting hammers . - Motive power for air motors which drive hoists and winches. - Blast cleaning or sandblasting of surfaces. - Spray painting - Engine starting as with diesel engine. - Control systems where compressed air is used both as a signaling medium and also to power actuating - devices such as air cylinders. - Atomizing of liquids such as oil for use as a fuel and water for use in humidifying. - Soot blowing for boiler furnaces.

Air Compressors Uses: 

Air Compressors Uses

ADVANTAGES OF COMPRESSED AIR OVER ELECTRICITY: 

ADVANTAGES OF COMPRESSED AIR OVER ELECTRICITY Using compressed air to drive tools and other machinery has certain advantages over the use of electricity. - Compressed air machines can not be damaged by overloading, as can electric motors. When the load is too great, the compressed air machine simply slows down or stops. - Air driven hand tools are lighter in weight than the electric type. - Air driven hand tools do not become hot after extensive use as do the electric type. - No danger of electric shock to the operator. - Compressed air machinery may be used in explosive atmospheres without hazard because they are free from sparking contacts.

DISADVANTAGES OF COMPRESSED AIR OVER ELECTRICITY: 

DISADVANTAGES OF COMPRESSED AIR OVER ELECTRICITY Compressed air tools are usually more expensive than electrical tools. Air transmission piping more expensive. Air transmission piping more difficult to install than electrical wiring

AIR COMPRESSOR CAPACITY: 

AIR COMPRESSOR CAPACITY An air compressor's rated capacity is determined by the compressor's flow rate and discharge pressure under standard condition. The standard conditions of temperature 20 º C, pressure 1.013 Bar and humidity 36% are defined, immediately before the air suction point of the compressor. The flow rate is the quantity of air that a compressor is capable of pumping under standard conditions. The unit of flow rate is usually m3/min. Discharge pressure is in KPa. Rated Capacity : Refers to the highest possible flow rate and discharge pressure for a given compressor under standard conditions. Operating Capacity : It depends on the conditions under which the compressor is operating. Change in inlet air pressure, air temperature, and humidity will induce changes in the operating capacity of the compressor.

CLASSIFICATION OF AIR COMPRESSORS: 

CLASSIFICATION OF AIR COMPRESSORS

RECIPROCATING COMPRESSORS: 

RECIPROCATING COMPRESSORS A reciprocating compressor is one in which the air is compressed by a piston moving in a reciprocating manner within a cylinder. The cylinder must be equipped with intake and discharge valves to control the flow of air entering and leaving. This type of compressor is used in a wide variety of applications including power plant service and commercial, industrial and mining installation. It is suitable for all ranges of pressure. Reciprocating compressors are made in a variety of designs or arrangements and may be divided into types according to cylinder arrangement, method of compression, method of drive and whether they are single or double acting .

DUBLE ACTING: 

DUBLE ACTING

MAJOR PARTS OF COMPRESSOR: 

MAJOR PARTS OF COMPRESSOR THE MAJOR PARTS OF COPMRESSOR: CYLINDER PISTON DISCHARGE VALVE SUCTION VALVE CRANKSHAFT UNLOADER

CYLINDERS: 

CYLINDERS Compressor cylinders are made from cast iron for pressure up to 1000 Kpa or cast steel for pressure upto 6900 Kpa. When the compressor is in operation, the cylinder is heated due to the heat of compression and the friction of the piston rings. It is necessary to remove this heat and to maintain the cylinder at a reasonable operating temperature. This is done by means of water cooing or by air-cooling. If water-cooling is used then the cylinder is constructed with a chamber or water jacket surrounding the cylinder barrel through which cooling water is circulated. If air-cooling is used then the cylinder is constructed with integral cast fins which provide increased radiating area. More efficient cooling is obtained with water cooling than with air-cooling. The air-cooled machine, however, has the advantages of simple construction, less piping needed.

THE CROSS HEAD: 

THE CROSS HEAD The crosshead is of steel with upper and lower bearing surfaces, which contact the crosshead guides. A threaded hole is provided in one end of the crosshead into which the piston rod fits. The crosshead is of steel with upper and lower bearing surfaces, which contact the crosshead guides. A threaded hole is provided in one end of the crosshead into which the piston rod fits. The crosshead pin to which the connecting rod is attached is usually held rigid in the connecting rod and moves within bearings or bushings in each side of the crosshead. In some designs, however, the crosshead pin is securely fastened in the crosshead and the bearing or bushing is in the connecting rod end.

CONNECTING ROD: 

CONNECTING ROD Compressor connecting rods are constructed of forged steel and have a crankpin bearing at one end and an opening for the crosshead pin (or for the piston pin of a trunk type piston) in the other end.

CRANKSHAFT: 

CRANKSHAFT The compressor crankshafts are of forged steel and are usually made from a single forging which has been machined and ground to precision limits and drilled to provide oil passages for positive pressure lubrication. In order to balance reciprocating and rotating forces, the crankshaft may be made with counter weights as shown in Fig. 3-2-6, or else it may be the type shown in Fig. 3-2-7, which has opposing crank throws to provide balance.

CONNECTING ROD (Fig): 

CONNECTING ROD (Fig)

CRANKSHAFT: 

CRANKSHAFT

COMPRESOR VALVES: 

COMPRESOR VALVES Compressor valves are usually the automatic type which open and close on a pressure difference. Two commonly used designs are the plate or disc type and the channel type. A disc type valve is shown in Fig. 3-2-8. In the disc type valve in Fig. 3-2-8, the air entering through the ribbed upper body, forces the valve discs down against the cushioning action of the spring. The air then passes through between the valve discs and the valve seats and out through the ribbed lower valve body.

valve: 

valve

Valve parts: 

Valve parts

Slide 24: 

Last figer shows the parts of a channel type valve. In the channel type valve the port plate and the seat plate fit together with their passages or openings corresponding. The valve channels fit over these openings and are held down against the seat plate by the valve springs which fits inside the channels and are held in place by the stop plate. The air, entering through the port plate, pushes the channels up off the seat plate against the springs and the air then passes through the openings in the stop plate. Strips of self-lubricating material are placed within the channels to prevent metal to metal contact between the channels and the valve springs.

ROTARY COMPRESSORS : 

ROTARY COMPRESSORS Like the reciprocating compressor, the rotary compressor is classed as a positive displacement type. Several different designs are in use, the most common being : the sliding vane type, the lobe type and the screw type.

THE SLIDING VANE COMPRESSOR: 

THE SLIDING VANE COMPRESSOR The sliding vane compressor consists essentially of a cylindrical rotor having slots into which sliding vanes fit. The rotor is contained within a water jacketed cylinder or casing and is supported by bearings so that it is eccentric to the casing. As the rotor turns, the sliding vanes move out against the casing wall due to centrifugal force. Pockets of air are trapped between the vanes and the wall. These pockets decrease in volume, due to eccentricity, as the vanes move around the casing from the intake to the discharge and in this way the air is compressed