Liquid state makes cryogen or lube follows gas inlet valve of the attaint when inspiratory compressor air cylinder piece phenomenon, and after entering air cylinder, not was in exhaust procedure is quick eduction, in the moment that when the piston is close to top dead centre, be compressed and produces the phenomenon of high hydraulic pressure is called normally fluid is attacked. Fluid is attacked can cause inside very short time compress get power (like a powerful person piece, piston, connecting rod, crankshaft, piston pin) attaint, it is the deadly killer of reciprocating type compressor. Decrease or avoid a liquid to enter air cylinder to happen with respect to what can attack in order to prevent fluid, because this fluid is attacked,can avoid completely.

Process and phenomenon

Normally, fluid attacks a phenomenon to be able to be divided for two parts or process. Above all, when agent of refrigeration of more liquid state, lube both perhaps mixture is followed inspiratory when entering compressor air cylinder with higher rate, be pounded as a result of liquid and incompressible, can cause inlet valve piece excessive bend or rupture; Next, in air cylinder when evaporating not in time to be compressed with the liquid of eduction by the piston, the enormous pressure that appears inside the instant is caused get power be out of shape and damage. These get power include to suck exhaust valve piece, mat of board of board of a powerful person, a powerful person, piston (coping) , piston pin, connecting rod, crankshaft, plain bearing liner.

1, connecting rod ruptures

The time that reduces the travel makes an appointment with 0.02 seconds, and exhaust process will be briefer. The droplet in air cylinder or liquid must be inside so short time from steam vent eduction, speed and momentum are very big. Exhaust valve piece circumstance and inlet valve piece identical, different point depends on exhaust valve piece have spacing board and spring piece prop up, break off not easily. When impact is severe, spacing board also can be out of shape cock.

If the liquid did not evaporate in time to give air cylinder with the platoon, the meeting when the piston is close to top dead centre compresses a liquid, because time is very short, this compresses liquid process to seem is to bump, metallic knock sound also can come out in crock lid. Compressing a liquid is the another share that fluid hits a phenomenon or process.

Fluid attacks the maximum pressure that generates for an instant to have very big broken annulus sex, the connecting rod that people is familiar with first bends to rupture even outside, other compress get power (mat of board of board of a powerful person, a powerful person, crankshaft, piston, piston pin) also can have be out of shape or damage, but often be ignored, as exorbitant as steam exhaust pressure perhaps confuse sth with sth else. When overhauling compressor, people can discover the connecting rod that bend or ruptures very easily, give replace, and forget an examination whether does other part have be out of shape or damage, bury next an apple of discord for the following breakdown thereby.

Fluid attacks the connecting rod that cause to rupture unlike hold axis and piston in the arms to bite a crock, it is OK resolution comes out. Above all, fluid is attacked cause connecting rod to bend or rupturing happen inside short time, connecting rod the piston of two end and crankshaft motion freely, won’t have commonly wear away badly to hold an axis in the arms or bite a crock what cause. Although inlet valve piece after breaking off, a powerful person piece drossy also can cause severe redraw of piston and air cylinder face to hurt now and then, but exterior cut and lubricant invalidation are caused wear away very different. Next, fluid attacks the connecting rod that cause to rupture is caused by pressure, connecting rod and break stubble to have extruding feature. Although the piston bites the connecting rod after the crock to rupture to also have,squash likelihood, but premise is the piston must get stuck dead to be in air cylinder. Hold postaxial connecting rod in the arms to break off more different, connecting rod big head and crankshaft have wear away badly, cause the force that break off to belong to shearing force, decide crop different also. Finally, hold in the arms axis and before biting a crock, electric opportunity excess load runs, electric machinery is calorific and serious, hot protector is met movement.

2, inlet valve segment is cracked

Compressor is the machine that reduces gas. Normally, the piston is minutely compress gas 1450 times (half compressor) or 2900 (seal compressor completely) , finish namely inspiratory or the time of exhaust process is 0.02 seconds shorter even. The suction on board of a powerful person the size of steam vent diameter and suck exhaust valve piece flexibility and intensity all are according to aeriform flow design. From a powerful person piece angle getting power is told, the wallop of the generation when gas flows is evener.

Liquid density is gas tens of count hundredfold even, the momentum when consequently the liquid flows is gotten greatly than gas much, the wallop of generation also is gotten greatly much. Inspiratory in be mingled with is more the flow when droplet enters air cylinder belongs to two-phase to flow. Two-phase flows in inlet valve piece on the concussion of generation not only intensity big and frequency is tall, be like typhonic be mingled with to wear cobble is beaten go up in glazing, its are ruinous it is self-evident. Inlet valve segment is cracked is the typical feature that fluid attacks and one of processes.

Case study

The liquid that can cause compressor fluid to attack nothing more than as follows a few kinds:

1, take fluid to start

When the refrigeration that return vital energy compressor is being started, the phenomenon with the acuteness and bubbly lube inside crankcase makes take fluid to start. The bubbly phenomenon when taking fluid to start can inspect lens to go up to observe clearly in oil. Taking the prime cause that fluid starts is dissolve in lube and heavy below lube many refrigeration agent, boil suddenly when pressure is reduced suddenly, cause the bubbly appearance of lube. The time length that lasts frothily and the amount that make cryogen are concerned, be a few minutes normally or ten minutes. A large number of bubble float on fat face, was full of crankcase even. Once pass intake duct inspiratory air cylinder, cause fluid very easily to attack. Apparent, take fluid to start the fluid that cause to attack happen in the process that start only.

With answer fluid to differ, with “ refrigeration agent the means of migratory ” enters crankcase cause the refrigeration dose that takes fluid to start. Refrigeration agent is migratory be when showing compressor stops to move, the refrigeration agent in evaporator in order to enrage bodily form type, through answering gas to pipeline enters compressor and be absorbed by lube, or inside compressor condensation hind and lube compound process or phenomenon.

Compressor stops machine hind, temperature can be reduced, and pressure will be elevatory. Because the refrigeration agent vapour in lube divides depress, can absorb the refrigeration agent steam on fat face, cause crankcase gas to control the appearance under evaporator atmospheric pressure. Oily Wen Yu is low, vapour pressure is lower, to refrigeration agent steam absorb force to heal big. The vapour in evaporator is met slowly “ of Xiang Qu axle box is migratory ” . In addition, if compressor is outdoor, when weather is cold or in night, its temperature often compares indoor evaporator low, the pressure inside crankcase is low also, refrigeration agent is migratory it is easy also to arrive after compressor enter lube by condensation.

Refrigeration agent is migratory it is a very slow process. Compressor machine down time is longer, migratory the refrigeration agent in lube can be jumped over much. Liquid state of the existence in wanting evaporator only makes cryogen, this one process can undertake. The lubricating oil that because dissolved,makes cryogen is heavier, it will be heavy the bottom in crankcase, and above lube still can absorb float more refrigeration agents. Divide outside causing fluid easily to attack, refrigeration agent is migratory return can attenuant lube. After very rare lube is sent each attrition face by oil pump, may strong rinse drops original oil film, cause wear away badly (this kind of phenomenon often calls refrigeration agent to erode) . Transfer wear away can make cooperate clearance to greaten, cause leakage oil, what affect further position thereby is lubricant, serious when can cause movement of oil pressure protector.

To older system, stop agent of refrigeration of the liquid state in compressor letting smoke dry evaporator before machine (call manage to find time stop machine) , can from go up at all avoid refrigeration agent migratory. And segregator of fluid of gas of the installation on the pipeline that return vital energy, can increase the resistance with refrigeration migratory agent, reduce migratory amount. Of course, through improving compressor composition, can prevent refrigeration agent migratory, and slow down lube is bubbly degree. Through improving an oil path pathway inside the refrigeration that return vital energy compressor, toll-gate increases on the passageway with electric machinery antrum and migratory crankcase (scavenge oil pump) , stop machine hind to be able to cut off access, refrigeration agent cannot enter crankshaft antrum; The passageway that reduces intake duct and crankcase is sectional and OK pressure of the crankcase when slow down switchs on the mobile phone drops speed, control bubbly degree and bubble to enter the amount of air cylinder then.

2, answer fluid

Normally, answering fluid is the phenomenon that the agent of liquid state refrigeration in the evaporator when showing compressor moves passes inspiratory pipeline to return compressor or process.

Expand to using the refrigeration system of a powerful person, time fluid and expand type selecting of a powerful person and use undeserved closely related. Expand type selecting of a powerful person crosses set of big, degree of superheat incorrect or method of installation of lukewarm bag of too small, feeling is adiabatic bag puncture caustic, expand malfunction of a powerful person causes a fluid possibly. capillary to using small refrigeration system, the quantity that add juice crosses congress to cause a fluid.

Use steam thawy system incidental answer fluid. No matter use 4 a powerful person to undertake pump moves heating up, the refrigeration when still introducing steam by-pass valve moves, the meeting after frost of steam be in harmony forms a large number of liquids inside evaporator, these liquids move to return compressor likely already in the begining in subsequently refrigeration.

In addition, evaporator frost serious or conduct heat when fan breakdown become poor, the liquid that did not evaporate can cause a fluid. Frequent wave motion also can cause refrigeratory temperature expand to reaction of a powerful person is out of order and cause a fluid.

The fluid that answers fluid to cause attacks an accident to happen in air mostly refrigeration (cold or abbreviation wind is empty cold) close partly in compressor of dual class of compressor and stand-alone, the air cylinder because of these compressor and time tracheal be interlinked directly, once answer fluid, cause fluid very easily to attack an accident. Although did not cause fluid to attack, time fluid enters cylinder general dilute or erode piston and cylinder are mural lube, aggravate piston wears away.

Enrage to answering (refrigeration agent vapour) refrigeration close partly and whole sealing compressor, answer fluid to cause fluid to attack rarely. But the lube inside can attenuant crankcase. The lube viscosity that contains agent of refrigeration of many liquid state is low, in attrition the face cannot form enough oily film, cause movement wear away quickly. Additional, the refrigeration agent in lube encounters hot meeting to boil in carrying a process, carry what affect lube normally. And distance oil pump is further, the problem is jumped over apparently more serious. If the bearing of electric machinery end happens to wear away badly, crankshaft may sedimentation to a side, bring about stator easily to sweep hall and electric machinery burn down.

Apparent, answer fluid to be able to cause fluid to attack not only, return can attenuant lube to cause wear away. The bear of the electric machinery when wearing away and electric current can increase greatly, as time passes will cause electric machinery trouble. To answering the refrigeration system that fluid prevents harder, segregator of installation gas fluid and use manage to find time the harm that stops to engine control can be prevented effectively or reduce a fluid.

3, lube is too much

Close partly compressor has oil to inspect looking glass normally, so that watch oil level on any account. Oil of oil level prep above inspects lens limits, explain oil is too much. Oil level is too high, the crankshaft that high speed rotates and connecting rod are big strike oily area often with respect to the likelihood, cause lube to splatter in great quantities. Splattering lube once change enters intake duct, take air cylinder, cause fluid possibly to attack.

When setup of large refrigeration system is debugged, often need proper and additional lubricating oil. But bad to answering oil system, want to search an influence to answer oily germ seriously, blindly additional lubricating oil is dangerous. Although temporary oil level is not high, when also wanting to notice a large number of returning lube is abrupt (after changing frost for instance) the risk that creates possibly. The fluid that lube causes is attacked not infrequent.


Fluid is attacked is compressor common breakdown. Produce fluid to attack, the problem exists certainly in demonstrate a system or be being safeguarded, need tries to correct. The design that watchs analytic system seriously, construction and safeguard, find the source that causes fluid to attack not hard. Do not prevent fluid to attack from germ, and maintain breakdown compressor simply or change a new compressor, can make fluid is attacked only happen again.

2023-01-05T00:00:00-08:00January 2023|Categories: Air Compressor Technology|Tags: , , |