Summary: In petro-chemical industry, reciprocating type compressor is among them crucial equipment, if produced breakdown, the birth that can give petrifaction the company causes bigger loss, can browbeat even the life of people is safe. Reason this, detect with respect to what need to adopt science precautionary method, so that can discover fault in time and try to solve. The article basically diagnoses a method to undertake study around the breakdown of compressor of move back and forth.

Keyword: Compressor of move back and forth; Breakdown is diagnosed; Signal analysis

In the production such as industry of oil refine, fertilizer, compressor of move back and forth is among them key equipment, the moving stability of this equipment can affect the manufacturing efficiency of this industry directly. Of compressor of move back and forth run whether safe stability, with its breakdown is diagnosed and forecast a technology to having close relationship, because the structure of this equipment is more complex, fragile component is more, this makes the breakdown of this equipment produces probability bigger also, once malfunction, can bring bigger pecuniary loss. Be based on this, it is important that around breakdown of compressor of move back and forth diagnostic method undertakes study to have.

1 common breakdown identifies a method

Research technique of 1.1 typical test to failure

The breakdown type of compressor of move back and forth is relatively complex, and the happening of breakdown is uncertain, inside the use cycle of compressor of any a move back and forth, have bigger may malfunction, so, choose a compressor to have breakdown imitating test, manpower, material resources and financial capacity can be reduced on certain level. When undertaking to compressor of move back and forth breakdown is diagnosed, includes experiment method has a lot of planting, but as a whole, can be its cent the following measure.

(1) builds testing stand, the accident of compressor of imitate move back and forth happens.

(2) passes the processing to the following kinds of signal: The first, oscillatory signal; The 2nd, displacement signal; The 3rd, heating power signal. Need to undertake handling to oscillatory signal especially, the oscillatory character that concerns to its and breakdown itself undertakes extracting.

(3) writes relevant algorithm, to be being diagnosed automatically and early-warning technology has thorough research.

(4) changes breakdown to diagnose the online system that monitor to undertake developing to intelligence.

1.2 signal analyse a processing technique

In the process that runs in compressor of move back and forth, the mutual coupling between its component makes breakdown presents the following kinds of character: Linear of a kind of dispute is characteristic, another kind is frequency modulation character. This becomes unusually difficult with respect to the analysis that brings about pair of breakdown feature signal and processing. Through ceaseless research, reached the following kinds of signal handle analytic method.

1.2.1 when frequency analyses a way

What frequency analysis law points to when is through coming up to undertake to signal in time axis statistic is analysed, it belongs to a kind of conventional fault signal to analyse a way, can come out the expression with the intuitionistic feature of signal. What spectrum analysis points to is time domain signal change is frequency domain signal, through Fourier commutation is decomposed, decompose for single harmonic signal, this is having better effect to the processing of stable state signal. Reason this, in domain of instrument of a favourable turn coming back, the methodological application that processing of this kind of signal analyses is relatively wide.

Small wave and 1.2.2 small bag analysises

Alleged small analysis, it is actually when what frequency analyses is outspread and develop, even if is in different frequency band, different hour, what can realize signal is detached, law of this kind of analysis can overcome the limitation that Fourier alternates effectively. What small bag analysis points to is differentiate frequency band multilayer, undertake decomposing to doing not have the high frequency part of fractionize, can make the extraction of breakdown feature becomes so more refine. Going up to be not the processing of stable state signal, with the tradition when photograph of frequency analysis method is compared, small bag analyses a way more advanced, get admissive on the processing of signal of feature of compressor of move back and forth.

1.2.3PCA signal processing technique

Alleged PCA analyses a way, those who point to is count manage model through building, undertake decomposing to diagnostic signal data, so that get its feature vector, undertake its permutation again, in order to seek advocate diagnostic vector. When to compressor of move back and forth gas a powerful person undertakes breakdown is diagnosed, advocate the parameter that diagnostic vector is an outbalance, can regard temperature of breakdown of gas a powerful person as diagnostic parameter of change its, judge breakdown next according to the metabolic quantity of this eigenvalue.

1.3 monitor diagnostic method commonly

The diagnostic parameter signal of compressor of move back and forth basically includes oscillatory signal, heating power signal, noise signal to wait. In this heating power signal includes to discharge baric force, capacity to wait a moment again. Undertake monitoring an analysis to these signal, can help the main type that judges breakdown. Current, relatively common breakdown diagnoses the method that monitor to have the following kinds.

Function of 1.3.1 heating power monitors a law

In compressor of move back and forth, temperature is a very sensitive feature parameter, undertake monitoring to the change of temperature, can help maintenance technician know the working position of compressor interior spare parts. For example if exhaust valve appears flat phenomenon, so in inspiratory process, with respect to the phenomenon that can appear to suck, the temperature that can make enrage a powerful person so is ceaseless and elevatory. In apply when temperature monitors law of this one party, sensor can put in airframe outside side, need not change housing structure so, the operation rises to also go to the lavatory exceedingly.

Compressor of move back and forth includes in locomotive process inspiratory, compress, exhaust, expand etc. In these 4 processes, pressure shows periodic change, whether does compressor lie in a normal moving condition, can be mirrorred by curve of change of force of crock internal pressure. For example, if inlet valve appears the circumstance of leak, so its inspiratory process pressure can be lengthened somewhat, its exhaust process can shorten somewhat, and expand process curve also can produce change. Because pressure measures a dot to be inside the crock, build other perhaps position part to want obligate installing hole in the crock so, in apply when pressure is monitored, need notices this.

1.3.2 noise monitor a law

In noise signal, have the signal that mechanical equipment runs, these signal have the signal of surroundings not only, still have the signal of other noise source. Reason this, diagnose in the breakdown of compressor of move back and forth in, noise is monitored also can assist a method as a kind. Carry pair of noise sensor apply, to compressor of move back and forth signal of medium typical breakdown noise undertakes departing extracting will be henceforth the research heat that breakdown diagnoses. The breakdown sort of compressor of move back and forth is more, a breakdown can bring about many features parameter to produce change. Reason this, undertaking to compressor of move back and forth breakdown is diagnosed when, need has a consideration to the associated sex between multi-parameter, can undertake accurate identifying to breakdown type so. Besides, in diagnostic system of breakdown of compressor of move back and forth, artificial intelligence system also is applied rather in, make so breakdown diagnostic technology obtained greater progress, make its reached the height that intelligence changes.

1.3.3 oily fluid monitor a law

Alleged oil fluid is monitored, those who point to is put the emphasis compressor lube, undertake to its oily fluid is analysed, undertake detecting to grain wearing away inside sample, detect its size, appearance, this kind of method that monitor is relatively good. For example, with iron chart the method such as analysis, spectral analysis undertakes monitoring to the wear out condition of compressor.

1.3.4 vibration check

Diagnose in the breakdown of reciprocating type compressor in, law of oscillatory test analysis is among them a kind of most basic measure, also be among them a kind of the most significant step. The join of compressor whether to become loose, its cooperated precision to whether produce change, can pass oscillatory signal report to come out. Pass the reasonable analysis of pair of oscillatory signal, can help detect the substantial information that personnel obtains compressor position.

1.3.5 iron chart is analysed

When undertaking monitoring to the wear out condition of the kinematic pair inside compressor crankcase, applying iron chart to analyse is a good auxiliary method. But if the kinematic pair that makes many akin material pledge is existing,wear away when breakdown, this method is put in the limitation with particular move, can undertake distinguishing to the place of breakdown hard. Reason this, detecting in the process, can add up to its and other method suitably only apply.

Law of 1.3.6 shock pulse

Inside reciprocating type compressor, have many concussion Zhen Yuan normally, these concussion signal are relatively strong, a few relatively puny pulse along with sense signal undertakes flooding. Reason this, if will undertake breakdown detects to the scroll bearing of compressor, so shock pulse law cannot produce effect, but can regard relative standard as its, the around that will realize this pair of machine is comparative, can use its at analogy differentiate is being made between model aircrew together commonly.

1.3.7 detect operating mode parameter

Through undertaking monitoring to the parameter of the following respects of compressor, if discharge baric force, lube quantity to wait, provide useful information to search the breakdown of the concerned branch of compressor.

2 development trend

Now nowadays, the diagnostic technology of the following kinds of breakdown had obtained greater progress, the technology becomes more and more mature, if piston annulus wears away, heavy demote of lever of breakdown of gas a powerful person, piston. But, in the interior of compressor of move back and forth, it is relatively difficult that the trouble that has a few components is diagnosed, for example of crankshaft connecting rod rupture breakdown identifies very hard, additional of piston lever rupture breakdown also is diagnosed hard. Relevant document puts forward, can use the crankshaft that monitor this kind of method of converse load, will come true to run the judgement of condition to piston lever, but the dependability of this kind of method is insufficient. Reason this, diagnose research to the breakdown of compressor of move back and forth currently not quite comprehensive still. Now nowadays, the connection of some scientific research units and petrifaction enterprise still is not exceedingly close, a lot of research technique lie the imitate phase of the lab, the breakdown case data of petrifaction enterprise did not get be usinged effectively, fail to form intellectual database of the system. Reason this, the communication that needs to strengthen scientific research unit and petrifaction business cooperates, build with respect to what conduce to breakdown case knowledge base so, also conduce to typical breakdown diagnosing normative formation.

3 epilogue

The place on put together is narrated, the structure of compressor of move back and forth is relatively complex, component is more, the probability that malfunctions so is bigger also, and once malfunction,can cause bigger effect to the production of the enterprise. Accordingly, adopt corresponding diagnostic method with respect to need. Will undertake diagnostic to the breakdown of compressor of move back and forth. But the method that handles to the analysis of all sorts of feature signal is having certain limitation, can combine many breakdown case database so, combine a variety of analysis methods organicly again next rise, development intelligence diagnoses a system, can raise the accuracy rate that breakdown diagnoses so.