1, screw type compressor
Screw type compressor calls screw compressor again. 20 centuries 50 time, compressor of type of fuel injection screw applies on refrigeration unit, because its structure is simple, fragile little, can fall in the operating mode that great pressure is differred or pressure compares, exhaust temperature is low, much to be being contained in refrigeration agent lubricating oil (often call wet journey) not sensitive, have lose tolerance adjustment sex goodly, held the scope of application of compressor of high capacity reciprocating type very quickly, and ceaselessly to medium capacity limits outspread, apply on the refrigeration unit such as refrigerant, cold storage, air conditioning and chemical craft widely.
The screw type that is lead plane with it heats up pump from 20 centuries begin to be used at respect of heating air conditioning at the beginning of 70 time, available gas heat source, hydro-thermal pump, heat reclaims model, glacial harbour is cold model etc. In industrial respect, for energy-saving, yi Cai heats up pump to make heat reclaim with screw type.
2, centrifugal type compressor
Centrifugal type compressor is a kind of lamina rotates type compressor (namely turbine type compressor) . In centrifugal type compressor, the impeller that high speed rotates gives centrifugal force of gas effect, and the spread that gives gas in enlarge pressing passageway controls function, make aeriform pressure gets rising.
Inchoate, because this kind of compressor is only comfortable at low, the circumstance of middling pressure force, large flow, and do not notice for people place. As a result of the development of chemical industry, all sorts of large chemical plant, of refinery build, centrifugal type compressor makes the crucial machine of all sorts of gas in compress and carrying chemical industry to produce, and have all in all place. The achievement that studies as the aerodynamics makes the efficiency of centrifugal compressor rises ceaselessly, because high pressure is sealed, little flow is narrow the treatment of impeller, the development of the technical key such as bearing of much oilier wedge is successful, solved centrifugal compressor to high-pressured force, a series of problems that wide discharge limits develops, make the applied limits of centrifugal type compressor expands greatly, as a result can replace compressor of move back and forth in a lot of circumstances, and expanded greatly to use range.
3, compressor of piston of move back and forth
It is a the development in of all kinds compressor is the earliest kind, the wooden bellows that China invented BC 1500 is the embryo of compressor of piston of move back and forth. 18 centuries end, england makes the first industrial compressor of air of piston of move back and forth. 30 time begin 20 centuries appear labyrinthian compressor, appear again subsequently all sorts of notting have oil-lubricated compressor and diaphragmatic compressor. What 50 time appear is right move model the structure makes the dimension of compressor of piston of large move back and forth is reduced greatly, and realized stand-alone multi-purpose.
Piston compressor use history is long, it is at present China is used must make compressor at most. Because its pressure range is wide, can get used to wider energy range, have high speed, much crock, energy adjustable, thermal efficiency is tall, applying to a variety of operating mode to wait for advantage; its defect is a structure complex, fragile many, overhaul cycle is short, sensitive to wet journey, have pulse vibration, run smooth sex to differ.
Screw compressor is a kind of new compression device, it and reciprocating type photograph compare:
① machine structure is compact, volume is minor, cover an area of an area little, weight is light.
② thermal efficiency is tall, add workpiece little, the spare parts gross of compressor has the 1/10 of piston only. The machine is fragile little, moving on the safe side, the operation is safeguarded simple.
③ gas is done not have pulsatile, movement is smooth, aircrew does not need special foundation ④ not high to the foundation to move in to rotor antrum fuel injection, exhaust temperature is accordingly low.
⑤ is not sensitive to wet journey, wet vapour or a few liquids are entered inside machine, attack danger without fluid.
⑥ can move below higher pressure ratio.
⑦ but change of pilot valve of have the aid of reduces effective travel, can undertake the stepless cold quantity of 10~100% adjusts.
Need complex oil to handle equipment, the oily segregator that asks detached effect is very good reachs the device such as oily condenser, noise is bigger, be in commonly 85 decibel above, need sound insulation measure.
Centrifugal type and piston photograph are compared, have rotate speed tall, tolerance is big, mechanical wear is small, fragile little, safeguard simple, consecutive working hours is long, vibration is little, move smooth, low to fundamental requirement, when atmosphere is measured, the quality of unit power unit light, volume is minor, cover an area of an area little, tolerance can adjust in the stepless inside the limits of 30%~100% , easily multistage is compressed and reduce expenditure, can satisfy the requirement of flow of certain chemical industry, implement automation easily, to large scale computer, can use the industrial turbine with taller economy to procrastinate directly move, this has economic advantage to having company of the steam that abandon heat. Defect is: Noise frequency is taller, cooling water is used up big, the meeting when the operation is undeserved produces asthma brace up.
3 kinds common reduce refrigeration chance (reciprocating type. Screw type, centrifugal type)
Function characteristic is compared
In refrigeration system, working because of compressor of reciprocating type refrigeration and compressor of screw type refrigeration on the principle different, the pressure loss that affects them so and leak losing reason also are different.
To compressor of reciprocating type refrigeration, the sealing when the quality that main reason is gas a powerful person and gas a powerful person shut the pressure loss that affects it and leak losing. Because want to overcome bedspring resistance when inlet valve open,this is (compress bedspring) and when gas has banished gas a powerful person, because pass sectional and lesser, rate of going from place to place is higher, reason produces resistance of certain going from place to place, accordingly, compressor of reciprocating type refrigeration is in in inspiratory process inside air cylinder pressure constant of gas under the aeriform pressure in inspiratory canal; Manage together, the pressure constant prep above in the gas inside the air cylinder in exhaust process sucks compressor of reciprocating type refrigeration enrage the aeriform pressure in the canal. If the passageway of gas a powerful person is sectional smaller, criterion obstruction loss is bigger. If a powerful person piece weight is great, the bedspring power of gas a powerful person is great also, criterion obstruction loss also increases, such pressure fasten numerical value to be reduced.
To compressor of screw type refrigeration, the pressure loss that affects it and leak losing are main the velocity of flow that the reason is gas.
In compressor of screw type refrigeration, the function stand or fall of screw is a key. If the flute profile of screw is symmetrical circular arc model, so its production is simple. If the flute profile of screw is asymmetrical line, so amount of its snail transporting gas is large, efficiency is tall. If reduce the long way of screw to compare, can make screw has good strength, increase the dependability that compressor of screw type refrigeration runs, the way that and be helpful for makes compressor of screw type refrigeration is compared to high-pressured force develops.
In compressor of screw type refrigeration, diameter and length size are same two pairs of screw, rotor area utilization factor is worth a big pair, its capacity is large. From apparently look, rotor area utilization factor is bigger, better to the function of compressor of screw type refrigeration. But, if rotor area utilization factor is too big, can reduce the intensity of screw and stiffness.
In compressor of screw type refrigeration, reduce the tine number of screw, can increase the acreage between the tine of screw, increase the capacity of compressor of screw type refrigeration. From apparently look, the tine number of screw is less, better to the function of compressor of screw type refrigeration. But, if the tine number of screw is too little, can reduce the bending strength of screw and stiffness.
In compressor of screw type refrigeration, raise the circumferential rate of screw, the exterior dimension that can make compressor of screw type refrigeration medium and quality when reduce, gas passes the opposite leakage rate of the clearance in compressor of screw type refrigeration to be able to decrease, be helpful for improving the cubage efficiency of compressor of screw type refrigeration and thermal efficiency. From apparently look, the circumferential rate of screw is rapidder, better to the function of compressor of screw type refrigeration. But, if the circumferential rate of screw is too rapid, increase gas with respect to can corresponding ground sucking the inside circumferential speed flow between steam vent mouth and tine loss.
In 3 kinds of common refrigeration compressor (type of reciprocating type, screw, centrifugal type) in, what reciprocate arises is inertial the main drawback that standing is compressor of reciprocating type refrigeration. What because often get,reciprocate arises is inertial, so the gas a powerful person in compressor of reciprocating type refrigeration and brace linkage mechanism are defeated the most easily change.
In 3 kinds of common refrigeration compressor (type of reciprocating type, screw, centrifugal type) in, the tremendous noise of the generation when movement is the main drawback of compressor of screw type refrigeration. Because often be carried refrigeration agent gas by periodic high speed,suck, steam vent mouth, and the influence that brings through the reason such as the leak of aperture, must choose reasonable screw movement rate in compressor of screw type refrigeration so.
In 3 kinds of common refrigeration compressor (type of reciprocating type, screw, centrifugal type) in, breathe heavily brace up the main drawback that is compressor of centrifugal type refrigeration.
The asthma that causes compressor of centrifugal type refrigeration brace up because,the reason is, when into water when the cooling water of condenser the quantity reduces fixed rate, the discharge of compressor of centrifugal type refrigeration is reduced very small, serious gas appears to take off in its passageway stream, its outlet pressure drops suddenly. Although compressor of centrifugal type refrigeration and condenser are jointly job, but the pressure of the gas in condenser is not at the same time bring down, then the pressure of the gas in condenser is more than the outlet pressure of compressor of centrifugal type refrigeration instead, the gas in causing condenser flows backwards to compressor of centrifugal type refrigeration in, till the aeriform pressure in condenser drops,arrive till the outlet pressure that is equal to compressor of centrifugal type refrigeration.
This is, compressor of centrifugal type refrigeration begins again to condenser aspirated, discharge increases, compressor of centrifugal type refrigeration returns to normal the job. But, when condenser medium aeriform pressure also renews original aeriform pressure when, the discharge of compressor of centrifugal type refrigeration is reduced again, the outlet pressure of compressor of centrifugal type refrigeration has begin to drop, gas arises again flow backwards. Such go round and round, produce the oscillation phenomenon of periodic air current. It is so in compressor of centrifugal type refrigeration, the cooling water quantity of condenser shoulds not be too small, can make be in compressor of centrifugal type refrigeration when movement otherwise, produce intense vibration, serious when what can make compressor of refrigeration of didymous and centrifugal type even is broken change.
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Summary: In refrigeration system, as a result of 3 kinds of common refrigeration compressor (type of reciprocating type, screw, centrifugal type) have the characteristic that differs severally. Accordingly, they have respective advantage and respective drawback on function.