Gas compressor - Wikipedia, the free encyclopedia. A small stationary high pressure breathing air compressor for filling scuba cylinders. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids. Types of compressors. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Samsung Galaxy S III 2012: Succeeded by Samsung Galaxy S4. Find latest news coverage of breaking news events. Change language & content: Switch to Latino. With the latest News & Advice from Manta, you can stay ahead of the trends and challenges affecting your industry and help your small business succeed. Infinite Prime Alarm Manual Dansk. Posted on 11-Aug-2016 . Deep Sleep Battery Saver 4.3. 014 Genie Universal Infinity Box McnPro Speakerphone. Choose Region Choose Your Location Please select your location and language so our site. Manual: June 09 2015 : PowerMaster Family B. Manual for Bulova Watch Diamond 96R19 free download. Download free Infinite Prime Alarm Manual Dansk software. Dansk manual Ved salg inden den 10. Produkt: Tyverialarm: M Hande Yener Serdar Orta. They can be either stationary or portable, can be single or multi- staged, and can be driven by electric motors or internal combustion engines. Larger reciprocating compressors well over 1,0. W) are commonly found in large industrial and petroleum applications. Discharge pressures can range from low pressure to very high pressure (> 1. MPa). In certain applications, such as air compression, multi- stage double- acting compressors are said to be the most efficient compressors available, and are typically larger, and more costly than comparable rotary units. Their application can be from 3 horsepower (2. W) to over 1,2. 00 horsepower (8. W) and from low pressure to moderately high pressure (> 1,2. MPa). Rotary screw compressors are commercially produced in Oil Flooded, Water Flooded and Dry type. The efficiency of rotary compressors depends on the air drier. The rotor is mounted offset in a larger housing that is either circular or a more complex shape. As the rotor turns, blades slide in and out of the slots keeping contact with the outer wall of the housing. Rotary Vane compressors are, with piston compressors one of the oldest of compressor technologies. With suitable port connections, the devices may be either a compressor or a vacuum pump. They can be either stationary or portable, can be single or multi- staged, and can be driven by electric motors or internal combustion engines. Dry vane machines are used at relatively low pressures (e. Pa or 2. 9 psi) for bulk material movement while oil- injected machines have the necessary volumetric efficiency to achieve pressures up to about 1. Pa; 1. 90 psi) in a single stage. A rotary vane compressor is well suited to electric motor drive and is significantly quieter in operation than the equivalent piston compressor. Rotary vane compressors can have mechanical efficiencies of about 9. The vane geometry may be involute, archimedean spiral, or hybrid curves. The compression of gas occurs by the movement of a flexible membrane, instead of an intake element. The back and forth movement of the membrane is driven by a rod and a crankshaft mechanism. Only the membrane and the compressor box come in contact with the gas being compressed. Generally stiff metal diaphragms may only displace a few cubic centimeters of volume because the metal can not endure large degrees of flexing without cracking, but the stiffness of a metal diaphragm allows it to pump at high pressures. Rubber or silicone diaphragms are capable of enduring deep pumping strokes of very high flexion, but their low strength limits their use to low- pressure applications, and they need to be replaced as plastic embrittlement occurs. Diaphragm compressors are used for hydrogen and compressed natural gas (CNG) as well as in a number of other applications. Reciprocating compressors were used to compress the natural gas. The reciprocating natural gas compressor was developed by Sertco. A mixture of air and water generated through turbulence is allowed to fall into a subterranean chamber where the air separates from the water. The weight of falling water compresses the air in the top of the chamber. A submerged outlet from the chamber allows water to flow to the surface at a lower height than the intake. An outlet in the roof of the chamber supplies the compressed air to the surface. A facility on this principle was built on the Montreal River at Ragged Shutes near Cobalt, Ontario in 1. A diffuser (divergent duct) section converts the velocity energy to pressure energy. They are primarily used for continuous, stationary service in industries such as oil refineries, chemical and petrochemical plants and natural gas processing plants. With multiple staging, they can achieve high output pressures greater than 1. MPa). Many large snowmaking operations (like ski resorts) use this type of compressor. They are also used in internal combustion engines as superchargers and turbochargers. Centrifugal compressors are used in small gas turbineengines or as the final compression stage of medium- sized gas turbines. Diagonal or mixed- flow compressors. The diffuser is often used to turn diagonal flow to an axial rather than radial direction. They are used where high flow rates or a compact design are required. The arrays of airfoils are set in rows, usually as pairs: one rotating and one stationary. The rotating airfoils, also known as blades or rotors, accelerate the fluid. The stationary airfoils, also known as stators or vanes, decelerate and redirect the flow direction of the fluid, preparing it for the rotor blades of the next stage. Beyond about 5 stages or a 4: 1 design pressure ratio a compressor will not function unless fitted with features such as stationary vanes with variable angles (known as variable inlet guide vanes and variable stators), the ability to allow some air to escape part- way along the compressor (known as interstage bleed) and being split into more than one rotating assembly (known as twin spools, for example). Axial compressors can have high efficiencies; around 9. However, they are relatively expensive, requiring a large number of components, tight tolerances and high quality materials. Axial- flow compressors are used in medium to large gas turbine engines, natural gas pumping stations, and some chemical plants. Hermetically sealed, open, or semi- hermetic. There is no route for gases to leak, such as around motor shaft seals. On this model, the plastic top section is part of an auto- defrost system that uses motor heat to evaporate the water. Compressors used in refrigeration systems are often described as being either hermetic, open, or semi- hermetic, to describe how the compressor and motor drive are situated in relation to the gas or vapor being compressed. The industry name for a hermetic is hermetically sealed compressor, while a semi- hermetic is commonly called a semi- hermetic compressor. In hermetic and most semi- hermetic compressors, the compressor and motor driving the compressor are integrated, and operate within the pressurized gas envelope of the system. The motor is designed to operate in, and be cooled by, the refrigerant gas being compressed. The difference between the hermetic and semi- hermetic, is that the hermetic uses a one- piece welded steel casing that cannot be opened for repair; if the hermetic fails it is simply replaced with an entire new unit. A semi- hermetic uses a large cast metal shell with gasketed covers that can be opened to replace motor and pump components. The primary advantage of a hermetic and semi- hermetic is that there is no route for the gas to leak out of the system. Open compressors rely on shaft seals to retain the internal pressure, and these seals require a lubricant such as oil to retain their sealing properties. An open pressurized system such as an automobile air conditioner can be more susceptible to leak its operating gases. Open systems rely on lubricant in the system to splash on pump components and seals. If it is not operated frequently enough, the lubricant on the seals slowly evaporates, and then the seals begin to leak until the system is no longer functional and must be recharged. By comparison, a hermetic system can sit unused for years, and can usually be started up again at any time without requiring maintenance or experiencing any loss of system pressure. The disadvantage of hermetic compressors is that the motor drive cannot be repaired or maintained, and the entire compressor must be replaced if a motor fails. A further disadvantage is that burnt- out windings can contaminate whole systems, thereby requiring the system to be entirely pumped down and the gas replaced. Typically, hermetic compressors are used in low- cost factory- assembled consumer goods where the cost of repair is high compared to the value of the device, and it would be more economical to just purchase a new device. An advantage of open compressors is that they can be driven by non- electric power sources, such as an internal combustion engine or turbine. However, open compressors that drive refrigeration systems are generally not totally maintenance- free throughout the life of the system, since some gas leakage will occur over time. Thermodynamics of Gas Compression. Isotropic Compression as used in ASME PTC 1. Code refers to a reversible, adiabatic compression process . Pressure) diagram comparing isentropic, polytropic, and isothermal processes between the same pressure limits. By making the following assumptions the required work for the compressor to compress a gas from P1. For the polytropic process (Pvn=constant. One common way of cooling the gas during compression is to use cooling jackets around the casing of the compressor. Real world cycles have inherent losses due to inefficient compressors and turbines. The real world system are not truly isentropic but are rather idealized as isentropic for calculation purposes. Temperature. Theoretical temperature rise is. The rise in air and temperature ratio means compression does not follow a simple pressure to volume ratio. This is less efficient, but quick. Adiabatic compression or expansion more closely model real life when a compressor has good insulation, a large gas volume, or a short time scale (i. In practice there will always be a certain amount of heat flow out of the compressed gas.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
November 2017
Categories |