CN200955966Y

CN200955966Y - Vortex street flowmeter vibration interference suppression system

Info

Publication number: CN200955966Y
Application number: CN 200620077104
Authority: CN
Inventors: 唐贤昭
Original assignee: JIANGSU WEIYI ELECTRONIC CO Ltd
Current assignee: JIANGSU WEIYI ELECTRONIC CO Ltd
Priority date: 2006-08-18
Filing date: 2006-08-18
Publication date: 2007-10-03
Anticipated expiration: 2016-08-18

Abstract

A vortex flow meter vibration interference suppression system suits for the mechanical vibration resistance of the vortex flow meter or other instruments. A flow signal sensor signal is connected with a charge magnifier module, an output terminal of the charge magnifier module is connected with a central frequency and a Q value controllable voltage tunable notch filter, a vibration interference signal sensor is orderly connected with a charge magnification module signal, a filter magnification module signal, a clamping limiting amplitude magnification module signal and a F-V conversion module signal and an output terminal of the F-V conversion module signal is connected with the voltage tunable notch filter. The system has a good suppression effect and a strong ability of spectrum inhibition and requires no phase and amplitude frequency characteristic of the vibration interference signal detection and a vibration interference signal detection consistency between an interference detection sensor and a flow senor. The system dramatically reduces the manufacturing process and precision requirement of the sensor , which has a significant practical value.

Description

A kind of vortex shedding flow meter vibration interference suppresses system

Technical field

The utility model relates to a kind of inhibition system of vortex shedding flow meter vibration interference, and the processing of disturbing with the anti-mechanical vibration of other gauge internal is disturbed in the anti-mechanical vibration that are specially adapted to vortex shedding flow meter.

Background technology

Design is disturbed in the anti-vibration of the strain-type vortex shedding flow meter of producing at present, mainly be divided into three kinds, first kind is to adopt differential amplification mode, make vortex flowmeter signals become differential wave by the sensor construction design, and the part of on-the-spot mechanical vibration undesired signal is rendered as common-mode signal, just in time offset by the piezoelectric ceramics of differential working method, adopt the superimposed mode of differential crystal packaging technology to be required high to the mode that the vibration of common mode suppresses, the various parameter requests of crystal are also very strict, require two crystal finishing encapsulation, back electromechanical properties unanimity is installed, thereby realize the amplitude-frequency of charge signal, phase propetry is in full accord, can provide to disturb and suppress actual effect, actual being difficult to realizes.Second kind, detect the synthetic of vibration signal or vibration signal and flow signal respectively, subtract each other by circuit then, this form sensitivity difference problem that two sensors pick up for undesired signal in solving first kind of mode, consistance for the sensor electromechanical properties proposes same high requirement, be difficult to equally realize, be difficult to see visible vibration interference in actual applications basically and suppress effect, even be enhanced on the contrary because of phase difference causes the undesired signal of some frequency.The third, adopt modern spectrum analysis treatment technology, filtering technique to suppress vibration interference, because the conspicuous contradiction between arithmetic speed and power consumption is difficult to overcome, the real-time of the signal Processing under the required precision can't be provided, with the actual a certain distance in addition of applying, practical effect is also relatively poor.

Summary of the invention

The purpose of this utility model is to design a kind of inhibition system of novel vortex shedding flow meter vibration interference, make it both comprise the advantage of existing flowmeter vibration-proof technology, can overcome the deficiency of prior art again, obtain reliable antivibration effect, simple in structure, real-time is good, highly versatile, low in energy consumption, it is required to satisfy actual two-wire system vortex shedding flow meter product, main innovation is to use electronic signal process to disturb inhibition, detecting element and flow detection sensor that mechanical vibration are disturbed do not have the requirement of characteristic coupling, specifically be to implement like this: a kind of vortex shedding flow meter vibration interference suppresses system, it is characterized in that the flow signal sensor signal connects the charge amplifier module, charge amplifier module output terminal connects centre frequency and the controlled voltage tunable trapper of Q value, the vibration interference signal transducer successively with the charge amplifier module, the filtering amplification module, clamp amplitude limit amplification module, F-V modular converter signal connects, and the voltage signal output end of F-V modular converter inserts the voltage tunable trapper.

With reference to figure 1, this system finishes:

The flow detection sensor output signal that 1. will be mixed with the mechanical vibration undesired signal is amplified through charge amplifier, gives centre frequency and Q value controlled voltage tunable trapper;

2. vibration interference detecting sensor output signal is amplified through electric charge amplification, filtering amplification, clamp amplitude limit,, frequency signal is converted to the control voltage signal through the F-V conversion.

3. the voltage signal that transforms out with the vibration frequency signal, promptly take out the vibration interference frequency that produces maximum interference for flow signal, go to control and give centre frequency and the controlled voltage tunable trapper of Q value, trapper trap centre frequency that dynamic control voltage is tunable, reach the purpose that suppresses vibration, by adjusting the Q value, realize disturbing the adjustment of inhibiting rate simultaneously.

In the utility model, the flow detection sensor output signal that is mixed with the mechanical vibration undesired signal adopts a second order active low-pass filter circuit after electric charge amplifies; The clamp amplitude limit amplifies the active filter that employing has the amplitude limit function, is made up of a single order Hi-pass filter and a variable low-pass filter; Be equipped with Schmidt trigger in the F-V modular converter, signal is converted to square-wave signal through the Schmidt trigger shaping, converts voltage signal again to; Signal after the amplification is after the F-V conversion, amplify with a single order low-pass filter circuit again, be defeated by the voltage tunable trapper by the voltage signal of voltage reversal device, centre frequency regulator and 3 FET amplifiers that the voltage tunable trapper is made up of a field effect transistor are formed.

System described in the utility model, suppress effective, it is strong that frequency spectrum suppresses ability, there are not phase place and amplitude versus frequency characte requirement for the detection of vibration interference signal, do not require the consistance that Interference Detection sensor and flow sensor detect for vibration interference yet, reduce the technology that sensor is made significantly, accuracy requirement, possesses significant practical value, the testing circuit working stability, reliably, the design of full employing hardware configuration, linearity height, the device susceptibility of circuit is low, convenient for production, can be widely used in being subjected to the anti-vibration of the bigger field instrument of on-the-spot vibration effect to disturb design, be a kind ofly reliable and effective vortex flow sensors to be detected the signal processing method that the vibration interference signal effectively suppresses in the Weak frequency signal.

Description of drawings

Fig. 1 is a block scheme of the present utility model.

Fig. 2 is a circuit diagram of the present utility model.

Embodiment

A kind of vortex shedding flow meter vibration interference suppresses system, the flow detection sensor output signal that at first will be mixed with the mechanical vibration undesired signal is amplified through the charge amplifier module, give centre frequency and Q value controlled voltage tunable trapper, simultaneously vibration interference detecting sensor output signal is amplified through electric charge, filtering is amplified, the clamp amplitude limit amplifies, change through F-V, be converted to the control voltage signal, go to control and give centre frequency and the controlled voltage-controlled trapper of Q value, dynamically control voltage-controlled trapper centre frequency, reach the purpose that suppresses vibration, by adjusting the Q value, realize disturbing the adjustment of inhibiting rate simultaneously.

Reference circuit figure, vibration signal sensor XT, detect Analysis of Pipe Vibrations, vibration signal is converted to electric signal by mechanical vibration, adopt charge amplifier U1D that the output signal of vibration transducer is advanced impedance conversion again, amplify in advance simultaneously, charge amplifier selects for use the MOS type of high input impedance far to put, C1, C2 are isolation capacitance, R ₁, R ₂Be input resistance, C ₃Be feedback capacity, R ₃Be feedback resistance, prevent that integration is saturated, C ₄, R ₄Be used to import balance.In order to eliminate or to reduce circuit noise and the influence of other interference to vibration survey, also need to use low pass and high-pass filtering circuit, so, adopt two operational amplifiers of U1B and U1C to form the active amplification filtering circuit of two-stage.The first order is a low-pass filter with fixed gain.Mainly be made up of operational amplifier U1B, it is the second order active low-pass filter circuit of a multiple feedback arrangement, and the gain in passband is R ₆/ R ₅, corner frequency and Q value are by R ₅, R ₆, C ₇, R ₈, C ₆Decision.The second level is an active filter with amplitude limit function, and this wave filter is made up of a single order Hi-pass filter and a variable second-order low-pass filter.High pass cut off frequency is by C ₈, R ₉Determine with R11.The cutoff frequency of low-pass filtering is by R ₉, C ₉, R ₁₀, R ₁₁, R ₁₂, C ₁₀Common decision.In signal amplitude hour, the gain of whole active filter in passband is-R ₁₂/ (R ₁₁+ R ₉); When input signal amplitude was big, after the diode conducting, output voltage amplitude was-(V _d+ V _In* R ₁₀/ R ₉), the V here _dBe the diode forward voltage drop; V _InOutput voltage for upper level.For can control filters, also need the vibration frequency conversion of signals is become voltage signal, the conversion of Here it is F-V, signal earlier in the F-V modular converter Schmidt trigger shaping be converted to square-wave signal, convert voltage signal again to.The output signal of U1C is directly inputted to the input end of U3.Work as U ₃When being output as low level, 4 of U3 is connected to " virtual earth " end of far putting.Average discharge current is I=Q/T=Ucc C in one-period ₁₁F, output voltage=-IR=-UccRC ₁₁F, U1A is a dc amplification circuit, is that a single order low-pass filter circuit amplifies R ₁₄, R _W1Be feedback resistance, C ₁₃Be feedback capacity, C ₁₂Be filter capacitor, C ₁₂, C ₁₃Play the smothing filtering effect.The output voltage of U1A is delivered to the voltage reversal device of being made up of U2A, and the output voltage of the voltage reversal device that U2A forms outputs to the grid of the field effect transistor Q of voltage tunable trapper.

The voltage tunable trapper, by the centre frequency regulator that 1 field effect transistor is formed, 3 FET amplifiers are formed.The effect of field effect transistor has been a centre frequency of adjusting trap.When the frequency of going into signal when output equals centre frequency that this extraneous voltage controls, just this frequency is suppressed to minimum.R _W2Be used to adjust notch depth, notch depth is greater than 50dB, and U2C and U2B consist of integrator, and DC current gain can reach 2500 times, and the U2D amplifier consists of summing circuit.The resistance R 17 of input flow rate signal Vi and this circuit, R19, R23, the R28 tie point is connected, C14, R17 is a feedback resistance electric capacity, strobe, R16 is an input resistance, R18 is a balance resistance, be connected to amplifier U2C by R19, the C14 integrating capacitor, another termination signal ground of R17, R20 is the input balance, second integrator of being made up of U2B exported in the output of U2C behind the centre frequency regulator, the output of U2C and C14, R31 connects, R31, R21, after connecting, R32 connects the drain electrode of field effect transistor Q, the source electrode of Q connects signal ground, the grid of Q links to each other with R16, R32 be attempted by between the drain electrode and grid of Q after C16 links to each other, R21, R23, R22, connect 6 pin of amplifier U2B after C15 links to each other, R24 is the input balance of U2B, and C15 is an integrating capacitor, R22 links to each other with the adjustable side of RW2, output 7 pin of U2B respectively with potentiometer RW2, R25 links to each other, R25, R27, R26 links to each other, another termination signal ground of R27, R26, R28, R29 connects 13 pin of summing amplifier U2D, R30 is the input balance of U2D, and R29 is the feedback resistance of U2D, and the output of U2D is fed back to signal input part through R18.

Claims

1. a vortex shedding flow meter vibration interference suppresses system, it is characterized in that the flow signal sensor signal connects the charge amplifier module, charge amplifier module output terminal connects centre frequency and the controlled voltage tunable trapper of Q value, the vibration interference signal transducer is connected with charge amplifier module, filtering amplification module, clamp amplitude limit amplification module, F-V modular converter signal successively, and the voltage signal output end of F-V modular converter inserts the voltage tunable trapper.

2. vibration interference according to claim 1 suppresses system, it is characterized in that and the charge amplifier module of flow signal sensor output signal connection, adopts a second order active low-pass filter circuit to amplify.

3. vibration interference according to claim 1 suppresses system, it is characterized in that clamp amplitude limit amplification module adopts the active filter with amplitude limit function, is made up of a single order Hi-pass filter and a variable low-pass filter.

4. vibration interference according to claim 1 suppresses system, it is characterized in that being equipped with Schmidt trigger in the F-V modular converter.

5. vibration interference according to claim 1 suppresses system, it is characterized in that the F-V modular converter connects a single order low-pass filter circuit amplification module earlier, is connected to the voltage reversal device again, and the output terminal of voltage reversal device inserts the voltage tunable trapper.

6. vibration interference according to claim 1 suppresses system, it is characterized in that centre frequency regulator and 3 FET amplifiers that the voltage tunable trapper is made up of a field effect transistor form.