As the ceaseless development of contemporary spin technology, compressed air to receive wide application. Spin industry compresses air application to bring twisting of eject of abb, air current, pneumatic to add wet, air current to carry in pneumatic pressurization, pneumatic, air current cleanness, pneumatic falls gauze, appearance accuses to wait for link oneself. Among them the dynamical source of air-jet loom is with compressing air serves as the carrier that bring abb, reduce air cost the amount is large, ask to reducing airy pressure and quality particularly strict. Compressing air to produce a course is high cost can process, so pneumatics system makes a high cost can place. Thorough knowledge textile mills is the requirement of character, affirmatory to compressing air each use compressor of air of tolerance, right choice with gas dot (abbreviation pneumatics machine) reasonable design is compressed air stands and compress air to manage a network, the on the rails that to ensuring spin produces, managing the sources of energy is particularly important.
Spin reduces air condition parameter and quality
1. Compress air condition parameter
After air course is compressed, its pressure, temperature is elevatory, saturation contains wet quantity to reduce. Accordingly, compress airy main condition parameter is pressure, temperature, contain wet quantity to wait, its meaning and mutual changeover relation accord with a project thermodynamic rule.
1) pressure and temperature
As a result of the need that craft produces, its pressure has diverse demand, MPa is used to express for the unit more on the project. The air after compressing lifts as a result of temperature, after cooling processing achieves a requirement, need course sends a workshop again.
2) airy contains wet amount
Below constant temperature and pressure, the content of the vapor in moist air has a maximum. When reaching this one limit, redundant vapor is met from the separate out in moist air. The moist air that achieves maximum in content of the vapor below constant temperature calls saturated air. At this moment air contains wet quantity to call saturation to contain wet amount. Saturation contains the temperature of wet quantity and moist air and pressure to concern. Compress airy pressure to increase, when thermal drop is small, its saturation contains wet quantity to will be reduced, increase conversely. For example, assume the moist air temperature that reduces from beginning to end all is 30 ℃ , when when its pressure increases 0.8MPa by 0.1MPa, the saturation of moist air contains wet quantity to will reduce 3.22g/kg from 27.55g/kg. This shows, after moist air is compressed, as a result of its saturation contains wet quantity to be reduced greatly, did not achieve saturated moist air so, reach saturation likely and have many moisture separate out, condense in reducing air pipeline system. Accordingly, reduce air system must appropriate is collected, eliminate condensate reconciles to compress airy definitely dry problem.
3) pressure dew point
Below constant pressure, will compress air refrigeration to be called to the temperature when saturation compress temperature of airy pressure dew point, because this reduces airy pressure dew point,temperature is mixed contain wet quantity to answer relatively. In compress air in dry process, it is to will compress airy to contain wet quantity processing to arrive under the dew point temperature of constant pressure normally. In use, should compress airy temperature only not under temperature of its dew point, won’t have moisture separate out. Accordingly, temperature of dew point of commonly used pressure expresses to compress airy on the project dry degree.
2. Reduce airy quality
Spin uses the need that reduces air to be produced as a result of craft, besides having particular demand to reducing airy pressure, to reducing airy quality (the quantity that contain dirt, water content, oil content) also have higher demand. Accordingly, reducing airy quality also is one of basises that choose pneumatics machine and purifying device of form a complete set.
1) compresses air quality rating differentiate
Airy quality rating can consult the level of quality rating of air of grade level ISO 8573-1 with current international differentiates.
3. Each working procedure is opposite spin the demand that reduces air quality
1. Air-jet loom is right the demand that reduces air quality
Compressing air is the dynamical carrier that air-jet loom leaves abb. Cite the cloth cover quality of the on the rails of abb and fabric to assure eject, to compressing airy character and pressure must have strict regulation.
(1) air oil content. Jet brings what abb uses to compress air cannot oiliness or oiliness are infinitesimal. If compress the oiliness in air, can pollute fabric not only, and meeting adhere reachs reed to go up in nozzle, affect jet power and increase the resistance that bring abb, make bring abb aggravation. And oiliness air can pollute a car to ask air the environment, endanger human body health. Accordingly, must limit the oil content in compressing air strictly, <0.6mg/m3 of general requirement oil content. This requirement is level of the 2 grade in standard of quality rating of ISO 8573-1 air.
(2) air water content. The compression without dry processing contains certain moisture content in air, of its content more or less to depend on the vapor quantity in the moist air that is issued by the environment before inspiratory compressor, what it awaits a condition compatibly along with area, season is different and different. If moist air is medium vapor capacity is more, can make compress air to be divided in water of the separate out in pipeline, make tube wall rustily with adhere dirt, increase; of loss of pressure transporting gas to still can be opposite the nozzle of loom, reed and component are caused pollute and rust, affect the quality of fabric even. Accordingly, must undertake dry processing to compressing air. Normally the requirement compresses temperature of airy pressure dew point to be in 10 ℃ of 4 ～ , reach level of the 4 grade in standard of quality rating of ISO 8573-1 air namely.
(3) air contains dirt amount. Not clean air meets those who accelerate compressor to wear away, affect the use efficiency of loom and life, pollute cloth cover. Normally the requirement compresses airy to contain dirt to measure ≤1mg/m3, contain 5μm of ～ of grit diameter ≤3, reach level of the 2 grade in standard of quality rating of ISO 8573-1 air namely.
(4) pressure asks. General air-jet loom uses compress pressure of airy compressor exhaust to be as follows certainly:
Reduce exhaust pressure > press at the beginning of loom > loom cites abb pressure
Revolution of the sort of the norms of the exhaust pressure of compressor and loom, fabric, loom and switch on the mobile phone means is concerned. Take loom normally press first for 0.5MPa, compressor exhaust pressure is 0.6MPa, the norms that chooses compressor is a baric force of 0.7MPa. Cite abb and fabric quality to make sure air-jet loom is normal, compress air pressure to must be stabilized, and enter the pressure that air-jet loom enters the mouth to answer normally ≥0.5MPa.
4. Other place is right the demand that reduces air quality
As degree of spin equipment automation rise and of contemporary spin technology rise ceaselessly, compress air to regard a kind of motivation as the source, received very wide application, outside dividing air-jet loom, in spin ministry and preparative workshop to basically be used at pneumatic pressurization, pneumatic to fall the place such as cleanness of eject of splice of eject of twisting of eject of gauze, air current, air current, air current. Afore-mentioned place fall besides pneumatic pressurization and pneumatic gauze is opposite to compressing air quality to ask inferior (not standard of prep above ISO 8573-1 4 class) outside, the others place all is contacted with yarn, character requirement should is opposite with air-jet loom the demand that reduces air quality is identical. Use at the place of pneumatic pressurization, general requirement compresses air-jet loom of air pressure prep above, for 0.6 ～ 0.8MPa.
Screw type and centrifugal form function are compared
Textile mills is when the type selecting of pneumatics machine, should mix according to the capacity of pneumatics machine exhaust pressure demand, with efficiency province of tall, specific power consumption, operation maintains handy, price reasonable wait for an element to give priority to choose a target. To assure the quality of spin product, still must consider to compress airy to purify a requirement (namely anhydrous, mix without oil the) that do not have dirt. Additional, good adjustment should be had when requirement pneumatics machine is undertaking tolerance adjustment character and energy-saving effect. Undertake integration analysis to afore-mentioned problems only, making overall plans and take all factors into consideration, ability defines program of optimal type selecting.
Use at present more is machine of screw type pneumatics and machine of centrifugal type pneumatics, both photograph is compared, the main good point of screw machine is: Enter exhaust even, without pressure pulsatile, machine runs smooth, need not set gas tank, foundation Xiao can use even without the foundation screw of locomotive; fuel injection can obtain higher only course pressure to compare (highest can amount to 20 ～ 30) and inferior exhaust temperature; , namely the effect that capacity suffers exhaust pressure scarcely, pressure comparing and rotate speed, density has nothing to do basically, special agree with much chance paralell connection moves. Defect is: Air quality is poor, oil content is high, cause attaint; noise easily to equipment tall, must adopt noise elimination to decrease capacity of; of measure of a confusion of voices and centrifugal photograph smaller.
The main good point of machine of centrifugal type pneumatics is: Structure compact, weight is light, the pure operating mode that do not have oil runs stand-alone capacity big; , compress air not to suffer lube to pollute, efficiency of character tall; is tall, managing the sources of energy. Airy character reachs 1 grade level (defect of ISO8573-1) of general standard of international of airy quality rating is: Start and jockey easy generation breathes heavily in the process brace up phenomenon, generation is oscillatory. Unfavorable use paralell connection of much stage set to move, when stand-alone capacity and force of platoon atmospheric pressure can satisfy a requirement, appropriate chooses less chance stage to undertake air feed.
The characteristic using gas of textile mills air-jet loom is discharge smooth, pressure is not high (P≤0.7MPa) and demand atmospheric pressure is stable (△ P≤0.01MPa) , count in cloth machine stage accordingly more, compress air waste time to measure big, with baric force the inferior, place appropriate that stabilizes with tolerance uses; of centrifugal type compressor
When selecting engine of centrifugal type pneumatics, follow the following and general principle even.
(The capacity of 1) compressor and exhaust pressure should satisfy the requirement of craft. As a result of the change of climate condition or the wave motion of the bear that use gas, force also can make the capacity of compressor and platoon atmospheric pressure change accordingly. Accordingly, compressor always is not secured in an operating mode the dot moves, move inside area of certain operating mode however. When choosing compressor, should make the operating conditions area of compressor includes the effective scope of application in its character curve as far as possible in.
(The efficiency of 2) compressor is deciding the economy that its run normally, accordingly, should choose as far as possible rated (design) efficiency is tall, efficient the aircrew with wider area.
(3) is become when operating conditions change is bigger, should choose to have good adjustment the aircrew of function and reliable and safe protection system.
(4) compares stable, stand-alone when bear when capacity and exhaust pressure all can satisfy a requirement, general appropriate chooses air feed of only station set.
(Below the premise that 5) asks in contented air feed, bulk of do one’s best small, weight is light, decrease cover an area of an area, facilitate safeguard the overhaul, save investment.
(6) falls in following case, appropriate uses air feed of paralell connection of much stage set. Bear change is bigger, only station set suits hard adjust the; when operating mode must increase aeriform supply and gas of the; when not newer existing compressor needs dosage very big, pass with over all dimension of a compressor big or make on when having difficulty.
The compressor of shunt-wound job can use the unit of same function standards, the aircrew; that also can use different performance standards is former better because of the harmonious sex between aircrew and application is wider, latter applies to bear only change is bigger, need to start the case of auxiliary unit teamwork work when height bear, shunt-wound aircrew no matter capacity size, its discharge baric force must equal or basic equal.
Selecting engine of centrifugal type pneumatics, when deciding its run parameter, should notice to prevent asthma brace up operating mode and jam the influence of operating mode, want to define the stable work area of centrifugal type compressor.
Compressor of centrifugal type air is by impeller belt take offense body does high speed to rotate, make gas produces centrifugal power, because gas controls flow in the enlarge in impeller, the velocity of flow after making gas passes impeller thereby and pressure get rising, produce continuously piece compress air.
Compressor of centrifugal type air belongs to speed type compressor, job of compressor of air of centrifugal when the bear that use gas is stable type is stable, reliable.
① structure compact, weight is light, capacity limits big;
② is fragile little, movement reliable, life grows;
③ exhaust does not suffer lube to pollute, tall; of air feed character
The efficiency when ④ is big quantity is tall, and be helpful for energy-saving.
Mechanic of centrifugal type pneumatics makes a principle
Centrifugal pneumatics engine is main by rotor and stator two much are comprised. Rotor includes impeller and axle. There is blade on impeller, still have in addition balance dish of one part that seals with the axis. The main body of stator is housing (air cylinder) , arrangement is returned to have diffuser, tortuous path, circumfluence on stator implement, tracheal, vent-pipe and partial axis seal spurt etc. The working principle of centrifugal compressor is, when impeller high speed rotates, gas as rotate, below centrifugal force effect, gas is swung in the diffuser from the back, and vacuum district is formed in impeller place, at this moment the new gas of the outside enters impeller. Impeller rotates ceaselessly, gas ceaselessly inspiratory swing piece, maintained continuous flow of gas thereby.
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Machine of centrifugal type pneumatics relies on the change of kinetic energy to increase aeriform pressure. The rotor that should take blade (work namely annulus) when roll, blade drives gas to turn, result deliver gas, make gas achieves kinetic energy. After entering stator share, because the enlarge of stator approachs pressure head of action speed energy,changeover becomes needs pressure, speed is reduced, pressure is elevatory, the oriented function that uses stator part at the same time enters impeller of below one class to continue step up, finally by spiral case eduction. To each compressor, need pressure to achieve a design, the progression that every compressor sets different amount is mixed paragraph of number, have composition of a few cylinder body even.
Spin industry is added play machine, air-jet loom, before spin etc use machine of centrifugal type pneumatics to compress air section to restrict the cost of 15% than buying.