CN2128729Y

CN2128729Y - Portable pachymeter

Info

Publication number: CN2128729Y
Application number: CN 92222396
Authority: CN
Inventors: 王新平
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-05-23
Filing date: 1992-05-23
Publication date: 1993-03-24
Anticipated expiration: 2002-05-23

Abstract

The utility model relates to a portable pachymeter, comprising a pulse generator, a probe, a travel range positioning device, a probe protection device, an amplification shaping circuit, a sampling circuit, an SCM system, etc., characterized in that an electromagnetic ultrasonic emitting and receiving device comprises the protective films of the travel range positioning device and the probe protection device, an axial direction telescopic outer sleeve, coil curls, pole shoes, and a permanent magnet. The protective films are positioned on the front end of the axial direction telescopic outer sleeve, and the coil curls are positioned behind the protective films. The probe comprising the coil curls, the pole shoe, the permanent magnet is arranged inside the travel range positioning device and the probe protection device.

Description

Portable pachymeter

The utility model is a kind of ultrasonic thickness test instrument that does not need acoustic couplant, is suitable for the measurement of ferrimagnet in-service pipeline wall thickness.

The method of comparatively practical thickness measuring has following several in the prior art:

1, rays method: this method is to utilize the penetrative characteristics of ray (rays such as α, β, γ), according to the quantitative relationship of transmissivity and testee thickness, determines the thickness of testee.

2, laser-beam deflection technique: this method is to utilize two light path systems, make at the uniform velocity deflection of laser beam, deflect into the required time of measurement point E of making on the measured object surface from zero point (it be give earlier by a certain incident angle α of laser beam and determined some O of optical receiver system optical axis direction) by the Laser Measurement bundle by the picture axle, according to formula:

d＝A Sin（t）Cosβ／Sin［α＋β＋γ（t）］Cosα

Obtain on the testee (or down) surface to imaginary zero plane apart from d, can calculate the thickness of testee thus; α is the laser beam incident angle in the formula, and β is the angle of optical receiver system as shaft position, the angle of deflection when γ (t) scans measurement point for laser beam from zero point, and A is the distance of laser beam device to imaginary zero plane.

3. piezoelectric supersonic method: this method is to utilize ultrasonic propagation that acoustic couplant produces piezoelectric transducer in measured object, by measuring the thickness of echo and definite testee of the time interval of emission.

All there is certain shortcoming in above method: rays method has certain harmfulness to human body, and not high to the measuring accuracy of tubing; The shortcoming of laser method is that structure is complicated, the cost height, and these two kinds of methods all can't be implemented in the measurement of service pipeline wall thickness; The shortcoming of piezoelectric supersonic method is the acoustic couplant that can't solve more than 250 ℃, and low to the measuring accuracy of the pipeline wall thickness of small curvature radius, poor repeatability.

The purpose of this utility model is the wall thickness measuring instrument that a kind of portable in-service pipeline will be provided, and it can measure the wall thickness of in-service pipeline rapidly and accurately.

Task of the present utility model is finished by the following method: will be by coil, pole shoe, the probe that permanent magnet is formed is near testee, after this coil feeds high-frequency pulse signal, then in the zone of testee, produce eddy current near coil, under the effect in the magnetic field that permanent magnet produces, the inside particle of eddy region is with stressed, particle in the testee is shaken, thereby in testee, produce ultrasound wave with tyrannical ripple and weak compressional wave, this ultrasound wave is propagated in testee, when running into the different interface of acoustic impedance, reflect, this reflection wave will be received by coil, the ultrasonic reflections signal that coil receives is through amplifying, shaping, sampling is sent into 8031 Single Chip Microcomputer (SCM) system and is carried out data processing, according to velocity of propagation and the time interval of the reflection wave one-tenth-value thickness 1/10 that calculate testee of ultrasonic transverse wave in testee.

Fig. 1 is the circuit block diagram of thicknessmeter,

Fig. 2 is the pulse-generator circuit schematic diagram,

Fig. 3 is sonde configuration figure,

Fig. 4 is a coil structure,

Fig. 5 is stroke location and probe protective device structural drawing,

Fig. 6 (a)～6(c) is the oscillogram of sample circuit.

Circuit block diagram of the present utility model is as shown in Figure 1: by pulse producer (1); probe (2), stroke location and probe protective device (3), amplification and rectification circuit (4), sample circuit (5), 8031 Single Chip Microcomputer (SCM) system (6), display (7), direct supply (8) are formed.

Pulse producer (1) circuit is as shown in Figure 2: having an output voltage is the Switching Power Supply (9) of 300 volts to 500 volts of direct currents, with by transistor T1, T2, T3 and an amount of resistance, the voltage-multiplying circuit that electric capacity R1～R9 and C1～C4 forms, the two ends of each capacitor are full of electric charge when static, when the trigger pip of being sent by 8031 Single Chip Microcomputer (SCM) system (5) is imported by input end A, transistor punctures successively, electric capacity at different levels forms the discharged in series loop, thereby obtains the wide pulse signal for the millisecond magnitude of probe (2) needed peak value 800～1500V at output terminal.

The probe (2) structure as shown in Figure 3: form by permanent magnet (13), coil (11), pole shoe (12).(10) be testee.

The structure of coil (11) is multi-turn (200～400 circle), plane, toroidal as shown in Figure 4.

Stroke is located and is popped one's head in protective device (3) as shown in Figure 5: be made up of diaphragm (14), axial stretching formula overcoat (15), locating piece (16), trigger switch (17), guide rod (18), spring (19), back seat (20).

Axial stretching formula overcoat (15) is connected with diaphragm (14) and locating piece (16) on it; axial stretching formula overcoat (15) moves relative back seat (20) with locating piece (16) when firmly depressing back seat (20); make by test coil (11) near testee (10); locating piece (16) is connected trigger switch (17) simultaneously; notify 8031 Single Chip Microcomputer (SCM) system (6); 8031 Single Chip Microcomputer (SCM) system (6) are behind the signal that receives trigger switch (17); send trigger pip to pulse signal generator (1); starting sample circuit (5) simultaneously samples; sample circuit (5) is notified 8031 Single Chip Microcomputer (SCM) system (6) after finishing sampling; 8031 Single Chip Microcomputer (SCM) system (6) receive sampling that sample circuit (5) sends finish signal after on display display message notifying operation person sampling finish, probe (2) can be moved apart testee (10).

Amplification and rectification circuit in the accompanying drawing 1 (4) is made up of limiter, bandpass amplifier, signal converter, and the ultrasonic echo signal that coil (11) receives forms the neat pulse signal of shape as accompanying drawing 6(a through amplitude limit, amplification, cutting) shown in.

Sample circuit in the accompanying drawing 1 is made up of binary counter, static memory, d type flip flop and NAND gate circuit, signal triggering counter and storer with a fixed frequency, to accompanying drawing 6(a) shown in signal storage, waveform is as accompanying drawing 6(b) and accompanying drawing 6(c) shown in, by this method detect the number of ultrasonic echo and count pulse number then the thickness of testee (10) be:

H＝NTC（1／2n）

Wherein: H--testee thickness,

Effective number of N--count pulse,

The number of n--ultrasonic echo,

T--inserts the cycle of pulse,

Hyperacoustic velocity of propagation in the C--testee.

Amplification and rectification circuit, sample circuit and 8031 Single Chip Microcomputer (SCM) system all are the custom circuits in the ultraspcchymeter, and those skilled in the art is known, and are not described in detail in this.

The utility model compared with prior art has the following advantages:

Simple in structure, certainty of measurement degree, need not acoustic couplant, can be implemented in to the high temperature testee below 500 ℃ labour and measure, the key technical indexes of this thickness gauge is:

Measurement range: 2～50mm

Measuring accuracy: 0.5%

Testee temperature: be not higher than 500 degrees centigrade

Measuring Time: less than 0.2 second

Claims

1, portable thicknessmeter, mainly form, it is characterized in that diaphragm in above-mentioned stroke location and probe protective device and axial stretching formula overcoat and coil, pole shoe, permanent magnet form electromagnetic ultrasonic wave emission, receiving trap by pulse producer, probe, stroke location and probe protective device, amplification and rectification circuit, sample circuit, Single Chip Microcomputer (SCM) system etc.; Diaphragm is at the front end of axial stretching formula overcoat, and coil is after diaphragm, and the probe of being made up of coil, pole shoe and permanent magnet is installed in above-mentioned stroke location and the probe protective device.

2, the portable thicknessmeter of claim 1 is characterized in that described coil is multi-turn, plane, ring-type.

3, the portable thicknessmeter of claim 1 is characterized in that described axial stretching formula overcoat and locating piece are fixed together, simultaneously motion.