CN2145375Y - Monitor for trends of fan blade - Google Patents

Abstract

The utility model relates to a monitor for the trends of fan blades. The monitor for the trends of fan blades realizes the on-line measurement of the fan blades. The monitor for the trends of fan blades makes use of the principle of electromagnetic induction to realize a digital detection for the shaking quantity of the fan blades. The monitor for the trends of fan blades comprises the magnetic induction sensor of blade amplitudes, the counter of blade amplitude value, a cyclic monitoring controller, an amplitude state-estimator, and a display and alarm circuit. Blade amplitude signals which are collected are sent to the counter to complete analog-digital conversion, and cyclic measures are implemented by a cyclic monitoring control circuit; at last, the true value of the blade amplitude is got by the amplitude state-estimator. Compared with the limit value, if the true value is over proof standard, the utility model alarms. Thus, the monitor for the trends of fan blades obtains the goal of online monitoring.

Description

Monitor for trends of fan blade

The utility model belongs to a kind of mechanical vibration surveying instrument, specifically utilizes inductive electromagnetic method to measure the instrumentation of fixed part amplitude in the dynamic object, particularly is applied to the amplitude measurement to fan blade.

Blower fan is to be widely used in the mine, the main equipment of industries such as metallurgy.In the mine, the major equipment that ventilates as the down-hole usually needs running continuously in 24 hours especially, shuts down to mean that promptly major accident can threaten mine and miner's safety.Over the years, the accident shutdown of blower fan but takes place repeatedly, and only the loss of blower fan itself is all very surprising.Among the numerous reasons of analysis accident, because the fatigue break of blade, leaf bar, and attachment screw is loosening when long-play has occupied Main Ingredients and Appearance, how to find the fatigue damage of fan blade early, becomes the problem that industry expert extremely pays close attention to already.At present, the method that prevents to take basically regular detection of such infringement.Every personnel of certain hour plant maintenance excessively will take blower fan apart and take off blade, check small slight crack whether occurs with methods such as ultrasound waves.Yet this detection method often can not prevent effectively that blade from tearing accident, and this is because all finish in very short time from the pulverizing that slight crack beats to whole blower fan occurring.Unlimited shortening is examined then, and the cycle is again impossible.So, the fracture accident of fan blade still often takes place, unique method is the kinetic measurement that realizes the fan blade state, the entire work process of monitoring blower fan, make the fatigue damage of early detection blade (and blade pole), yet, till the data that is retrieved, also be provided with On-line Measuring Method and the monitoring instrument of finding desirable fan blade up till now.

The utility model promptly provides a kind of instrumentation that utilizes the electromagnetic induction method that the relative amplitude under the blade running status attitude is monitored, and realize on-line monitoring whereby to the blade fatigue state, and accurately detect the blade that has been in earlier damage, thereby guarantee the safety of blower fan.

The fan blade of high speed rotating can be subjected to powerful windage resistance, and in effect lower blade integral body (comprising pole) the meeting generation deformation of windage resistance, the elastic-restoring force acting in conjunction owing to blade when windage changes makes blade produce relative the vibration with respect to fan shaft.Because fan blade was mostly done accurate transient equilibrium debugging, so the shape of blade, quality and stress all have good consistance.Thereby each blade all has a metastable amplitude with respect to the amplitude of rotating shaft.Though each blade amplitude is variant, do not have the difference of the order of magnitude, when fan blade or pole produced small fatigue crack (sometimes because of fixture loosening) then the amplitude of fan blade can produce bigger variation immediately, in general amplitude can obviously strengthen.Change as blade integral and be little this moment, and obvious influence is not produced in transient equilibrium, thereby be difficult to find with the general measure means.By a large amount of on-the-spot evidences that detect, this amplitude variations amount can be as the tendency signal of fatigue damage, for on-line monitoring provides foundation.The utility model promptly designs according to above theory and test findings.

Basic ideas of the present utility model are exactly the amplitude of each blade to be monitored out at random, and can report to the police timely and accurately when amplitude reaches critical value.For realizing above purpose, this monitor comprises following element in design: (1) amplitude sensor.It is mainly used to gather the amplitude signal of blade.When blade rotates on one side, on one side vibration is during by sensor, the sweep length that its sensor receives is the width of corresponding blade amplitude.Because randomness is arranged when being in the blade proximity transducer of vibrational state, maximum sweep width or minimum sweep length then may appear (when the sense of rotation blade is maximum displacement, blade enters the scanning area of sensor, and when rotation oppositely reaches maximum displacement, leave the sensor scan district and can produce maximum sweep length, otherwise can obtain minimum sweep length).This has just determined the amplitude width signal that is at every turn derived by amplitude sensor that the randomness in the certain limit is arranged.Have only and find out its maximal value and minimum value in the repeatedly duplicate measurements, the real amplitude of its difference ability and this blade has necessary relation.This is one of design key of the present utility model just.(2) counter.The functional requirement of this counter passes the amplitude width-pulse signal of coming as the counter time control signal with each amplitude sensor, thereby finishes the wide analog to digital conversion of amplitude.(3) circulatory monitoring controller.This partial circuit requires to firmly believe a blade and does cycle detection.Thereby obtain one group of data, therefrom find out maximal value and minimum value.Finally obtain the real amplitude of blade therefrom.The signal of being drawn by amplitude sensor divides one the road to deliver to the circulatory monitoring control circuit as synchronous triggering signal, the counter switch sum counter zero clearing of this signal in the conversion control counter, also will draw synchronous locking signal in this part circuit and deliver to latch in the amplitude state determinant, to latch the amplitude data of associated vanes by counter 2 outputs.(4) amplitude state determinant.To be amplitude data that counter is spread out of deliver to and obtain the real amplitude value in the subtracter through sending into big decimal latches after relatively respectively this partial circuit role again.(5) Display and Alarm Circuit.Amplitude data signals after judging is divided into two-way and is delivered to digital indicator in the circuit of this part, and another road is then sent into warning circuit and compared with the preset limit amplitude, exceeds standard value and then triggers warning circuit work.

According to above basic design concept, can realize the continual circulatory monitoring of fan blade.In case occur that amplitude increases then sound and light alarm and indicate the blade of fatigue damage immediately, thereby the generation of the incidents that averts a calamity.The embodiment that provides below in conjunction with accompanying drawing further specifies goal of the invention of the present utility model and how to realize:

Accompanying drawing 1 is the utility model structured flowchart.

Fig. 2 is the structure principle chart of amplitude sensor of the present utility model.

Fig. 3 is an embodiment electrical schematic diagram of the present utility model.

Wherein 1 is amplitude sensor, the 2nd, and counter, 2A are counter switch, and 2B is a high frequency signal generator, and 2C is a totalizer.3 is the circulatory monitoring controller, and 3A is a code translator, and 3B is the partial circulating counter, and 3C is the systemic circulation counter.4 is the amplitude state determinant, and 4A counts comparer greatly, and 4B is big number latch, and 4d is the decimal comparer, and 4C is the decimal latch, and 4e is the amplitude determinant, and 5 is Display and Alarm Circuit, and 5A is a display, and 5B is for comparing warning circuit.L is a magnetic induction coil, and P is an iron core, and K is high-strength permanent magnet.

For reaching goal of the invention of the present utility model, primary problem is dynamically being come out blade down with respect to the Oscillation Amplitude signals collecting of rotation axis.Obviously, be one of key Design of the present utility model as amplitude sensor 1.Accompanying drawing 2 has provided the embodiment of this part.From accompanying drawing 2 as can be seen, this part comprises an induction probe, come the amplitude width of sensing blade by it, it adopt poly-to signal be converted to behind amplifying circuit and shaping circuit that the square-wave signal that can react the amplitude width is delivered to counter 2 and circulatory monitoring controller 3 is further handled.Wherein induction probe is specifically by a magnetic induction coil L for iron core P, high-strength permanent magnet K and commutation diode VD2, and negative sense case position diode VD1 forms, and L also carries in DC circuit.Iron-core coil is contained in the long cylindrical shell, and permanent magnet K is located at end face.Be installed in during application make on the blower housing blade tip with possible minimum clearance near the permanent magnet K in the magnetic induction probe.Thereby the end face of the fan blade in the rotation near probe during end face cutting magnetic line cause that magnetic flux changes in the iron-core coil and produce induced signal that this signal adds to amplifying circuit through VD.Amplifying circuit constitutes voltage amplifier by triode VT1, resistance R 1, R2, voltage signal after the amplification is delivered to shaping circuit IC1, specifically can form by Schmidt trigger CD4093, through shaping induced signal is treated as rectangular pulse signal, promptly deliver to counter 2 as its switching signal as the amplitude width signal, circulatory monitoring controller 4 is delivered on another road, as synchronous triggering signal.

In order to finish quantification observing and controlling, set counter 2 is used for finishing analog to digital conversion, and this part comprises a counter switch 2A, high frequency signal generator 2B and totalizer 2C, totally three parts.High frequency signal generator 2B is that count pulse produces circuit, and it is by an integrated circuit CD4560, the 2MHz crystal, and resistance R 3 and capacitor C 1, C2 form a high-frequency oscillating circuits, can produce continuous high-frequency count pulse.Count pulse is delivered to totalizer 2C by counter switch 2A and is realized accumulated counts.2C can adopt integrated circuit CD4518 to form, counter switch 2A is one three and door, specifically can form by integrated circuit 4075, three with the door three input control lines be connected to amplitude sensor 1 respectively, the Q2 output terminal of code translator in high signal generator 2B output terminal and the circulatory monitoring controller.When Q2 end output high level, thereby fan blade scanning head district will produce the analog to digital conversion that continuous counter is realized amplitude.

Fan blade VIBRATION ANALYSIS according to the front is known, the sweep length that fan blade produced by when probe has randomness, have only and repeat repeatedly a certain blade circulation to be measured just may obtain real amplitude, the circulatory monitoring control circuit promptly is to finish this control procedure.From accompanying drawing 3 as can be seen this part, by code translator 3A, partial circulating counter 3B and systemic circulation controller 3C three parts are formed, code translator 3A can be made up of integrated package CD4514, partial circulating counter 3B is made up of integrated package CD4520, the systemic circulation controller is made up of integrated package CD4020, the output signal Q1-Q4 of partial circulating counter 3B links to each other with the address D 1-D4 of code translator 3A, the output signal Q2 of code translator be connected among the counter switch 2A three with a control line of door on, Q1 then is connected to the R end (clear terminal) of counter 2C, draw locking signal by Q3 and deliver to amplitude determinant 4, Q0 is connected to the CP end among the systemic circulation controller 3C, among Qn end (n is the fan blade number) and the systemic circulation controller 3C output signal Q8 by one or be connected to the R(zero clearing of partial circulating counter 3B) end, and be added in the CP end of partial circulating counter 3B from the synchronous control signal of amplitude sensor 1.After above structural design arrives the CP end of 3B when the synchronizing signal from amplitude sensor 1, the Q1 end of 3A is at first exported high level makes counter 2C zero clearing, the Q1 end output high level of 3A is opened at active scanning interval inside counting high-frequency impulse counter switch 2A to next blade behind the scanning probe district to reaching, and finishes analog to digital conversion.Then counting is ended after second blade leaves the scanning probe district.Because being arranged so that of Qn whenever just can be opened once through counter switch 2C behind the n-1 blade, be that corresponding fan blade circles and only a definite blade once monitored so guaranteed each partial circulating.When so CP has only counting to be 128 times (promptly blade is monitored in identification and finish 128 measurements) owing to the Q0 that is connected on 3A holds among the systemic circulation controller 3C in its multiple counting in this process, thereby Q8 transfers high level to resets partial circulating counter 2B, because 3C adopts the negative edge counting, so being the negative edge of 3AQ0 or the rising edge of Q1, the reset signal that 3B obtains produces constantly, changing to Q0 by Q1 again and missed an address pulse thereby so just make the output of 3A become Q1 by Q0, is next blade with regard to making measured Target Transformation also.Constantly samsara forms each blade continuous monitoring 128 times thus, the circulatory monitoring control procedure of changing a blade after per 128 times.

A blade is recorded 128 data continuously, therefrom find out maximal value and minimum value, subtract each other therefrom the actual value of taking out reaction blade amplitude then, the task of Here it is amplitude state determinant 4.From accompanying drawing 3 as can be seen this part by big several comparer 4A, big number lock 4B, decimal latch 4C, decimal comparer 4d and amplitude determinant 4e five parts are formed, physical circuit is by integrated package CD4585 * 4(4A), CD4042 * 4(4B), CD4042 * 4(4c), CD4585 * 4(4d), CD4560 * 4 and CD4561(4e) overlap joint form, divide 4 pass to 4A by the digital signal that counter 2C sends, 4B, 4C, 4D, the big or small number signal that (big decimal comparer and latch) finally latchs is by 4B, 4C takes out and delivers to amplitude determinant 4e, and the twos complementer that full adder of being made up of CD4560 in 4e and CD4561 form is obtained the id signal of difference as the blade amplitude.The required latch signal of latch (4B, 4C) is from the Q3 end of code translator 3A in the circulatory monitoring controller 3, replaces one by one and enters 4B through detecting in the digital signal that draws big number for 128 times like this, and decimal is replaced one by one and entered 4C, finally can draw the final value of amplitude.Intermediate value also can take out as reference by various demonstrations or writing circuit.

The last part of this monitor is a Display and Alarm Circuit 5, it is made up of light-emitting diode display 5A and comparison warning circuit 5B, the amplitude id signal that is taken out by amplitude determinant 4e is divided into two-way, one the road delivers to light-emitting diode display 5A is numeral demonstration directly perceived, be convenient to observed and recorded, comparison warning circuit 5B is delivered on another road, comprises in the 5B structure that a comparer and one are made up of the audio oscillator circuit that comparator output signal triggers, and comparer is made up of integrated package CD4585 * 2 and one dial switch.Dial switch is used for presetting the ultimate value of amplitude, makes alarm equipment alarm when exporting trigger pip from the digital signal of amplitude determinant 4e during greater than this limit.Simultaneously also can be by a series of technical measures and the auxilliary circuit locking systemic circulation controller that adds, repeat to monitor certain suspicious blade continuously, monitor can be got rid of exactly because of tunnel ventilation resistiveization, and undesired signals such as voltage ripple of power network monitor the presence of fatigue damage blade exactly.

Fan blade dynamic monitor according to above design concept composition, it can add a fritter permanent magnetism mark and be decided to be blade No. 0 on a certain fan blade when probe is installed, in testing process, can accurately locate like this fault blade, probe installs, be continuous monitorings in 24 hours of practicable fan blade, the setting of limit data often will detect according to the routine of every interior machine and finally determine, whole monitor can change operate as normal over to after limit system was determined, the amplitude data of fault blade is not from the normal value ultimate value that jumps quickly.The amplitude that should note each blade in class by the person on duty like this in case warnings that occur exceeding standard can be done auxiliary judgment according to note, prevents false alarm with the difference interference as reference.

In sum, above inventive concept formed one complete to the monitoring instrument of dynamic blade and feasible On-line Measuring Method.According to repetition test field observation, implement in the continuous on-line measurement and can accurately reflect the duty of each blade, particularly its actual amount of jitter and change procedure thereof.After it clearly detects amplitude ultralimit value, to recheck through ultrasound wave, its fatigue damage recombination rate is more than 95%.And this initial stage is damaged to destructive damage generally will considerable time (estimating at several hrs by several days), thereby, can prevent the generation of fan blade fracture accident effectively.This monitor is simple in structure, and operation judges is convenient, and is cheap, is suitable for the supporting and on-site on-line measurement of unit.So the utility model will provide sound assurance for the safe operation of blower fan.

Claims (8)

1, a kind of fan blade monitoring running state instrument, it is characterized in that this monitor is by amplitude sensor 1, counter 2, circulatory monitoring controller 3,5 five compositions of amplitude state determinant 4 and Display and Alarm Circuit, the blade amplitude width-pulse signal that is collected by amplitude sensor 1 divides two-way, one the tunnel delivers to counter 2 as the gate time control signal, circulatory monitoring controller 3 is delivered to as synchronous triggering signal in another road, deliver to counter 2 by the counting controling signal that circulatory monitoring controller 3 takes out, the synchronous locking signal that takes out is delivered to amplitude state determinant 4, amplitude signal after judging divides two-way, one the road delivers to the digital indicator 5A in the Display and Alarm Circuit 5, and warning circuit 5B in the Display and Alarm Circuit is delivered on another road.

2, monitor according to claim 1, it is characterized in that amplitude sensor 1 is by induction probe, amplifying circuit and shaping circuit three parts constitute, and the square wave that shaping forms is delivered to counter 2 and circulatory monitoring controller 3 as the width signal of amplitude.

3, according to claim 1 or 2 said monitors, it is characterized in that induction probe in the amplitude sensor 1 is by inductive coil L, iron core P, high-strength permanent magnet K, commutation diode VD2, negative clamping diode VD1 forms, the induced signal that is caused by the inswept probe end face of blade adds to amplifying circuit through VD2, amplifying circuit is adopted by triode VT1, resistance R 1, the voltage amplifier that R2 forms, voltage signal after the amplification is delivered to shaping circuit IC1, shaping circuit IC1 specifically can be made up of Schmidt trigger CD4093, and the rectangular pulse signal behind shaping circuit is delivered to counter 2 and circulatory monitoring controller 4 as the amplitude width signal.

4, according to the said monitor of claim 1, it is characterized in that counter 2 is by counter switch 2A, high frequency signal generator 2B and totalizer 2C three parts are formed, counter switch 2A forms with door CD4075 by one three, high frequency signal generator is by a CD4060,2MHz crystal and resistance R 3, capacitor C 1, C2 form, totalizer can adopt CD4518 to form, three with the door three control lines connect amplitude sensor 1 respectively, the Q2 output terminal among the code translator 3A in high frequency signal generator 2D and the circulatory monitoring controller 3.

5, according to the said monitor of claim 1, it is characterized in that circulatory monitoring controller 3 is by code translator 3A, partial circulating counter 3B and systemic circulation controller 3C three parts are formed, code translator 3A specifically can be made up of integrated package CD4514, partial circulating counter 3B is made up of integrated package CD4520, systemic circulation controller 3C is made up of integrated package CD4020, the output signal Q1-Q4 of partial circulating counter 3B links to each other with the address D 1-D4 of code translator 3A, the output signal Q2 of code translator 3A receive among the counter switch 2A three with a control line of door on, Q1 connects the R(zero clearing of counter 2C) hold and draw locking signal to amplitude state determinant 4 by Q3, Q0 is connected to the CP end among the systemic circulation controller 3C, Qn(n is the fan blade number) end and the output signal Q2 of systemic circulation controller 3C by one or door be connected to the R(clear terminal of partial circulating counter 3B), be added in the CP end of partial circulating counter 3B from the synchronous control signal of amplitude sensor 1.

6, according to the said monitor of claim 1, it is characterized in that amplitude state determinant 4 is by big several comparer 4A, big number latch 4B, decimal comparer 4d, decimal latch 4c, amplitude determinant 4e five parts are formed, physical circuit can be by integrated package CD4585 * 4(4A), CD4042 * 4(4B), CD4042 * 4(4c), CD4585 * 4(4d), CD4560 * 4 and CD4561(4e) overlap joint form, divide 4 the road to give big decimal comparer and latch, latch (4B simultaneously by the digital signal that counter 2C sends, 4C) latch signal is from the Q3 end of code translator 3A in the circulatory monitoring controller 3, big decimal signal is respectively from big decimal latch (4B, take out 4C) and deliver to amplitude determinant (4C), obtain the identification data of difference as the blade amplitude.

7, according to the said monitor of claim 1, it is characterized in that Display and Alarm Circuit 5 comprises light-emitting diode display 5A and compares warning circuit 5B composition, the amplitude id signal that is taken out by amplitude determinant 4e divides two-way, one the road delivers to light-emitting diode display 5A is the digitizing demonstration, and warning circuit 5B is delivered on another road.

8, monitor according to claim 7 is characterized in that comprising among the warning circuit 5B comparer and an audio oscillator circuit that is triggered by comparator output signal, and comparer can adopt integrated package CD4585 * 2 and a dial switch to form.

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