CN2064056U - Automatic controlling instrument of liquid specific gravity - Google Patents

Abstract

The utility model relates to an automatic controlling instrument of liquid specific gravity, comprising an oscillator, a specific gravity sensor, a temperature sensor, a liquid level sensor, an operational amplifier, a digital display, a combined gate circuit, a power supply circuit, etc. The utility model is characterized in that when the specific gravity of the liquid in the specific gravity sensor is changed, the float submerged in the liquid can float up and down and drive a signal head to move up and down in a coil to make the inductive reactance of the coil changed. If the coil is given a voltage with a certain frequency, the induced voltage can generate the relative variation and output an electrical signal.

Description

Automatic controlling instrument of liquid specific gravity

The utility model relates to automation field, is a kind of liquid specific gravity auto-controller that is exclusively used in wave-soldering unit.

Along with the continuous growth of televisor, radio cassette player demand, domestic many radio complete system plant is for improving the welding quality of radio audiovisual equipment, and adapts to the needs that streamline is produced, and mostly adopts wave soldering technology.In this technology, the concentration of scaling powder is quite big to the influence of welding quality, and therefore how the strict concentration of controlling scaling powder is the subject matter that guarantees welding quality.Normally adjust the concentration of scaling powder with thinning agent, to guarantee that scaling powder is in the scope of requirement all the time, carrying out along with welding, thinning agent in the scaling powder is volatilization constantly, scaling powder concentration just constantly increases, thereby this adjustment must continuously carry out, simultaneously, the amount of scaling powder also can constantly reduce, and must in time add.

To this, external wave soldering equipment all is equipped with the apparatus for automatic control that can detect scaling powder proportion (being concentration) automatically and adjust scaling powder concentration automatically.Domestic wave soldering equipment does not then all have the supporting of this kind instrument, and main dependence manually ceaselessly measured and liquid feeding, and this has not only increased labour intensity but also influence welding quality.

The purpose of this utility model is the instrument of the automatic controlling liquid proportion of a kind of energy of design.

Its main technical schemes is to include sample circuit in control instrument, signal amplification circuit, the composite door circuit, control circuit and power-supply circuit, the sensor that one novelty is arranged in sample circuit, this sensor is by coil, the immersion float, signal heads, composition such as suspension line and spring, wherein, empty tube shape float as sampling part is immersed in the fluid to be measured, and be hung on the spring by suspension line, a signal heads that is arranged in coil is arranged on suspension line in addition, when the proportion of fluid to be measured changes, float just fluctuates, driving signal heads moves up and down in coil, making telefault that corresponding induction reactance take place changes, to the voltage of telefault supply certain frequency, so induced voltage just changes the signal of this instrument sampling that Here it is with the inductance size.

Principal feature of the present utility model is as follows:

1, adopt advanced liquid specific gravity sensor, highly sensitive, good linearity, temperature effect is little, and the weight error is few.

2, instrument is provided with temperature measurement unit, can directly reflect the temperature of fluid to be measured, and by the temperature compensation curve that provides, the influence of proportion when correcting temperature changes.

3, instrument has digital Presentation Function, can directly indicate the proportion and the temperature value of fluid to be measured.

4, instrument is provided with proportion bound warning device, and the proportion upper lower limit value can be regulated within the specific limits continuously, sets alarming value arbitrarily, and can correspondingly add dilution or scaling powder by control loop, to reach the requirement of user's production technology.

5, instrument is provided with liquid level bound device, and when liquid level surpassed upper limit, instrument sent sound and light alarm, and when liquid level was lower than lower limit, instrument also sent sound and light alarm, simultaneously two charging valves is opened, and works within the specific limits to guarantee liquid level, as shown in Figure 2.

6, the instrument liquid-adding device also is provided with two kinds of liquid feeding modes, when liquid specific gravity changes among a small circle, can intermittently add solution, when liquid specific gravity reaches bound, just adds corresponding solution continuously, to quicken the adjusting of rate of specific gravity.

Fig. 1 is the structural drawing of proportion sensor.

Fig. 2 is the scheme of installation of proportion sensor, liquid level sensor and temperature sensor, and 14 are foaming groove, the 15th, scaling powder, the 16th, float, the 17th, temperature sensor, the 18th, liquid level sensor, the 19th, proportion sensor among the figure.

Fig. 3 is a circuit block-diagram of the present utility model, because of its wiring diagram is identical with like product, and the Therefore, omited wiring diagram.

Float 1 is immersed in the liquid among the figure, and be hung on the spring 7 by suspension line 2 and spring shaft 12, in the signal heads 4 that has to move up and down in can cavity 13 on the suspension line 2 at coil 5, when scaling powder changes because of proportion takes place for the factors such as volatilization of thinning agent, float 1 just fluctuates, driving signal heads 4 moves up and down in coil 5, making telefault that corresponding induction reactance take place changes, when giving the voltage of telefault certain frequency, its induced voltage just changes with the inductance size, the signal that this promptly takes a sample, 3 is lower covers among Fig. 1, the 10th, upper cover plate, the 11st, junction block, the 9th, spring bumper cover, the 6th, shell, the 8th, extension line.

Oscillator 20, proportion sensor 19, temperature sensor 17, liquid level sensor 18 and operational amplifier 21 constitute the sampling amplifier section among Fig. 3, and wherein proportion sensor 19 is core product branches of instrument, that is principal character of the present utility model.

Temperature sensor 17 is a semiconductor P-n structure, and along with the variation of junction temperature, the junction resistance value corresponding rectilinearity also takes place changes, and this sensor can keep good linear relationship, as shown in Figure 2 between-50～+ 50 ℃ after the constant current source differential pressure is amplified.

Liquid level sensor 18 is three probe-type structures, is divided into 3 positions, and needle point between the upper and lower apart from 20mm, also is about to level control (LC) respectively apart from 10mm in 20mm, has guaranteed the measuring accuracy of proportion sensor, as shown in Figure 2.

Oscillator 20 produces the voltage of a fixed frequency by the NE555 time base circuit, supplies with proportion sensor 19 as signal source.

Operational amplifier 21 is made up of secondary μ 741 integrated circuit, its course of work is amplified proportion sensor bridge differential voltage, through dividing potential drop conversion, input digit indicator gauge, indicated value is the actual specific gravity value, in addition, the electric bridge differential voltage is imported follower μ 741 after once amplifying, output voltage is delivered to the tertiary voltage comparer respectively, the first order is " upper limit ", and the second level is " lower limit ", and the third level is middle " trace is regulated ".

Composite door circuit 23---this partial circuit effect system delivers to controller and alarm by the inverter circuit OR circuit respectively with " upper limit ", " lower limit ", " trace is regulated " three kinds of signals.

Control circuit 24---this part circuit is that the signal with gate circuit provides respectively and opens the scaling powder operation valve or open the thinning agent operation valve, and reach the adjusting of feed flow flow, this circuit system adopts the square-wave oscillator of two NE555 time base circuits as EDM Generator of Adjustable Duty Ratio, because waveform is the half-wave EDM Generator of Adjustable Duty Ratio up and down, the time of relay circuit " open-minded ", " switching " can be set by technological requirement, be convenient to the accurate adjustment of external control device.

In the engage relay control loop, can also sound and light alarm on the instrument, with the working condition of alert.

22 is digital indicators among Fig. 3, the 25th, and power-supply circuit.

Claims (2)

1, a kind of liquid specific gravity auto-controller, by oscillator 20, proportion sensor 19, temperature sensor 17, liquid level sensor 18, operational amplifier 21, digital indicator 22, composite door circuit 23, compositions such as control circuit 24 and power-supply circuit 25, it is characterized in that immersion float 1 is arranged in proportion sensor 19, coil 5, signal heads 4, suspension line 2 and spring 7, when liquid specific gravity changes, the float 1 that is immersed in the liquid just fluctuates, and drive signal heads 4 moves up and down in the cavity 13 of coil 5, the induction reactance of coil 5 is changed, give the voltage of coil 5 certain frequencies, the corresponding variation just takes place in its induced voltage thereupon, exports an electric signal.

2, control instrument according to claim 1 is characterized in that liquid level sensor 18 has 3 probes, and the distance between the upper and lower of needle point can be set on request, is in the appropriate location all the time to guarantee the float 1 on the proportion sensor 19 in liquid.