JPH044998Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an oil concentration meter that automatically measures the oil concentration of wastewater by ultrasonic emulsification, for example, when draining water from a ship's bilge. .

<Prior art> Oil concentration meters using the ultrasonic emulsification method generally detect the turbidity of sample water sampled in a measurement cell, then emulsify the oil content in the sample water using ultrasonic waves, and then The turbidity of the sample water is detected again, and the oil concentration of the sample water is determined from the difference in turbidity before and after emulsification.

In such an oil concentration meter, if the oil content is not emulsified normally, the measurement results will contain a large error. In other words, it is an essential requirement for correct measurement that the emulsification device, ie, the ultrasonic generator, is operating normally.

In conventional densitometers of this type, the following method is adopted to check this.

One of them is a method that takes advantage of the fact that the turbidity of sample water increases during ultrasonic irradiation compared to the sample water turbidity before ultrasonic irradiation, and issues an alarm when this phenomenon does not occur.

The other method detects the temperature rise of the power amplification transistor or vibrator caused by mismatching between the ultrasonic oscillation circuit and the ultrasonic vibrator, and issues an alarm when the detected value exceeds a predetermined value. It's a method.

<Problems that the invention aims to solve> According to the former conventional method, there are cases where air bubbles are mixed into the sample water, SS components (solid suspended solids) are mixed into the sample water, or the sample water is colored. There is a problem that an alarm may be erroneously issued when the

Furthermore, according to the latter conventional method, when the ultrasonic generator operates intermittently, the detection time constant becomes particularly long, and it takes a long time to issue an abnormality alarm. A major drawback is that highly concentrated oil and water are discharged overboard.

The present invention has been made in view of the above, and aims to provide an oil concentration meter that can reliably and quickly detect functional decline in an ultrasonic generator and issue an alarm.

<Means for Solving the Problems> The configuration for achieving the above object will be explained with reference to FIG. 1, which corresponds to the drawings of the embodiment. A means (for example, a resistor 18 and Phase difference detection circuit 2
0, etc.), and means for comparing the detected data with a set value and generating an alarm output based on the comparison result (for example, the setting circuit 22 and the alarm signal generation circuit 21).
and when the above-mentioned phase difference exceeds a predetermined amount,
It is characterized by being configured to issue a warning of equipment abnormality.

<Function> Ultrasonic transducer 1 seen from the ultrasonic oscillation circuit 19 side
The equivalent circuit of No. 5 is as shown in FIG. The vibrator 15 is represented by R and L, and C represents a matching capacitor. In such a circuit configuration,
When the oscillation frequency of the oscillation circuit 19 and the resonant frequency of the vibrator 15 completely match, that is, when they are matched, there is only a resistance component, and the voltage and current applied to the vibrator 15 are in phase. When the matching is mismatched, a phase difference occurs in a predetermined direction between the voltage and the current depending on the direction of the mismatch. Therefore, by observing this phase difference, the normal state of matching can be ascertained, and if an alarm is issued when a phase difference exceeding a predetermined amount occurs, a reliable and prompt abnormality alarm will be issued.

<Example> An example of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

The measurement cell 1 has a sample water inlet 1a and an outlet 1b, and by opening the electromagnetic on-off valve 3, the sample water inside can be replaced. The turbidity of the sample water sampled in the measurement cell 1 is detected after the turbulence within the cell has subsided. Turbidity measurement involves making light from the light source 2 enter the sample water, inputting the detection outputs from the transmitted light detector 4 and the scattered light detector 5 to the differential amplifier 6, and calculating the ratio of both detection outputs. It is carried out by. As a result, light source 2
By reducing the effects of brightness fluctuations and sample water coloring, more accurate turbidity measurements can be performed.

After sampling the sample water, the measured turbidity value before emulsification is stored in the capacitor 8 by closing the switch 7.

The measurement cell 1 is equipped with a horn 16 connected to a vibrator 15, and after the above turbidity measurement and storage is completed, the ultrasonic oscillation circuit 19 is driven for a certain period of time to generate ultrasonic waves in the sample water. Emit sound waves to emulsify oil in sample water. After the turbulence during emulsification subsides, the output of differential amplifier 6 will indicate the measured turbidity after emulsification, and this output and capacitor 7
The difference between the pre-emulsification turbidity measurement and the value already stored in the emulsification is determined by the operational amplifier 9 in the next stage. When switch 10 is closed in this state, a signal corresponding to the above-mentioned difference is stored in capacitor 11. This stored value is amplified by the amplifier 12 based on the calibration value, thereby converting it into the oil concentration in the sample water. This value is digitized by the AD converter 13 and displayed on the display 14.

Each of the above parts is driven and controlled by a command signal from the sequence controller 23, and by repeating the above operations, sample water is successively sampled from the bilge wastewater and its oil concentration is measured.

A matching capacitor 17 is inserted between the ultrasonic oscillator circuit 19 and the ultrasonic vibrator 15, and a resistor 18 is provided to convert the current flowing through the vibrator 15 into a voltage signal. There is.
Current equivalent signal i extracted by this resistor 18
is introduced into the phase detection circuit 20 together with the input voltage signal v to the vibrator 15 extracted from the ultrasonic oscillation circuit 19. Phase detection circuit 20
A signal θ corresponding to the phase difference between the two signals is introduced into the alarm signal generation circuit 21. The alarm signal generation circuit 21 is mainly composed of a comparator, and compares this signal θ with a reference signal from the setting circuit 22, and issues an alarm signal when θ becomes larger than the reference value. It is configured like this.

Now, the equivalent circuit on the ultrasonic transducer 15 side viewed from the ultrasonic oscillation circuit 19 can be represented as shown in FIG. That is, the vibrator 15 is represented by R and L, and C is a matching capacitor. At the resonance point, the resonator 15 has inductive impedance, but in order to effectively send the power from the oscillation circuit 19 to the resonator 15, this C is inserted to perform matching, and the resonator side is reduced by only the resistance. That is to say.

In such a circuit configuration, when matching is achieved, that is, when the oscillation frequency of the oscillation circuit 19 and the resonant frequency of the vibrator 15 match, the voltage and current applied to the vibrator 15 are only the resistance component. Be in the same phase. However, if the matching deviates for some reason, as shown in Figure 3,
Depending on the direction of deviation, it becomes inductive or capacitive, producing a phase difference θ between the voltage and current applied to the vibrator 15. Therefore, the phase difference θ may be detected by the phase detector 20 and compared with a reference value set in advance in the setting circuit 22, and an alarm may be issued when the phase difference exceeds the reference value. For example, abnormalities in the ultrasonic oscillation circuit 19 and the vibrator 15 can be promptly notified.

In addition, although the above embodiment shows the case where the phase difference between the voltage and current applied to the vibrator 15 is directly detected, the present invention is not limited to this, and for example, the The power or reactive power is detected, and the points where these are the maximum or minimum are set as matching points, and when the actual measured value deviates from these points by more than a predetermined amount, an alarm is issued.In other words, the phase difference is determined. Of course, indirect detection can also be used.

<Effects of the invention> As explained above, according to the invention, the matching between the ultrasonic oscillation circuit that emits ultrasonic waves to emulsify the oil in the sample water and the vibrator is achieved by matching the voltage flowing through the vibrator with the voltage flowing through the vibrator. The structure is configured to monitor by detecting the phase difference of the current, and issue an alarm when the phase difference exceeds a predetermined amount, making it possible to accurately and quickly warn of functional decline in ultrasonic generation. Problems are solved all at once.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram showing the ultrasonic transducer 15 side from the ultrasonic oscillation circuit 19, and FIG. 3 is a block diagram showing the ultrasonic transducer 15 side. FIG. 2 is an explanatory diagram of a phase difference θ between a flowing voltage and a current. DESCRIPTION OF SYMBOLS 1...Measurement cell, 2...Light source, 4...Transmitted light detector, 5...Scattered light detector, 15...Ultrasonic transducer, 17...Matching capacitor, 18...
Resistor, 19... Ultrasonic oscillation circuit, 20... Phase detector circuit, 21... Alarm signal generation circuit, 22...
Setting circuit, 23...Sequence controller.

Claims (1)

[Scope of utility model registration request] A measurement cell is equipped with a means for detecting the turbidity of the sample water sampled, and an ultrasonic vibrator for irradiating the sample water in the cell with ultrasonic waves to emulsify the oil content, and the sample water before and after emulsification is provided. In a device that measures oil concentration in sample water from changes in water turbidity,
Means for detecting data related to the phase difference between the voltage and current supplied to the ultrasonic transducer from the oscillation circuit that drives the ultrasonic transducer, and comparing the detected data with a set value and issuing an alarm based on the comparison result. An oil concentration meter comprising means for generating an output, and configured to issue an alarm of device abnormality when the phase difference exceeds a predetermined amount.