JPS5851218B2 - Yubun-no-do-sokutei-souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an oil concentration measuring device for measuring oil concentration in oil-containing wastewater, which removes the influence of suspended matter other than oil and continuously measures only the oil concentration. Regarding.

The turbidity method, which irradiates light onto the sample in an optical cell and uses the transmitted light or scattered light, determines oil concentration.
Since the turbidity component caused by the turbidity (less than 5 solids referred to as SS) affects the output signal of the oil concentration, it has been required to prevent errors caused by this.

Conventionally, one solution to this problem was the
As shown in Japanese Patent Publication No. 47-26859, a method is known in which the turbidity of a sample water before emulsification and the turbidity after emulsification are determined and the difference between the two is detected.

However, since the detected turbidity activity changes exponentially, it is difficult to exclude the influence of SS by simply calculating the difference.

The present invention creates two types of emulsions with different emulsification states with a time lag from oil-containing wastewater, measures the transmitted light intensity of each, and calculates the ratio of both transmitted light intensities, thereby affecting floating solids SS. The purpose of the present invention is to provide a measuring device that measures a signal corresponding to the oil concentration that is not detected.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a photometry section of an apparatus according to an embodiment of the present invention.

In the figure, 1 is a cylindrical optical cell made of transparent glass, through which emulsified sample liquid A or B passes.

A light source 2 irradiates the sample liquid A or B in the optical cell 1, and a phototube 3 is placed opposite the light source to sense the intensity of the transmitted light.

4 is an ultrasonic emulsifier, which is driven by power from power source P1 or P2.

This power supply is configured to periodically alternately supply high power P1 and low power P'2.

The magnetostrictive vibrator 5 is excited by this power supply, and the oil in the wastewater sample is made into fine particles by the transmitter 7.

The inclined tube 17 is for concentrating the sample, and the sample that has entered the pipe 13 is sent to the cavity 7 through the gap between the inclined tube 17 and the transmitter 7, and after being secondary emulsified again, it is sent to the optical cell 1. are sent continuously.

10 is a thin film that prevents direct communication with the cavity 9.

A pump 12 is used to deliver the wastewater sample entering from the pipe 11 to the emulsifier 4 at a constant pressure.

The operation of photometry configured in this way will be explained with reference to FIGS. 2 and 3.

Figure 2 shows power sources P1 and P2 and the degree of emulsification of oil.
! It is a diagram.

The oil-containing waste water sent at a constant pressure by the pump 12 is driven by the low power P2 of the power source for an initial fixed period.

The sample moves to the static state of emulsification state B after a predetermined transient time.

After a short period of time, the power source is configured to supply high power P1, so that the degree of emulsification of the sample liquid is increased,
The oil content is made into finer particles than when the low power P2 is supplied.

After this high power P1 is supplied, a predetermined transition time passes and the emulsification state A shifts to a steady state.

In this way, the degree of emulsification of the oil in the sample changes depending on the level of power supply, causing undulations as shown in FIG.

Furthermore, this undulation is greatly affected by the concentration of oil in the wastewater sample.

The two types of emulsified states A and B thus created appear alternately by periodically repeating the high and low levels of the power supply.

Such a change in the degree of emulsification of oil also affects the intensity of transmitted light passing through each emulsified sample A and B, and the optical signals Sa and sb corresponding to samples A and B also have different forms of transmitted light intensity. show.

When measuring the turbidity of sample liquids A and B with suspended matter SS other than oil mixed in the wastewater sample liquid, optical cell 1
The transmitted light intensities JIA (X) and IB (X) that have passed through are expressed as IA (
X) = -IC-Y-10-(αX+βY) -----
--(1) IB(X) = ni', l0-Y-10(α″+
β′ Y) −−−−−−(2).

Here, α and α′ are proportional coefficients indicating the degree of emulsification of the sample samples A and B, and N′: parameters due to cell contamination and sample liquid coloring β and β′: proportional coefficient Y determined by the form of ss:
Sensitivity of the light-receiving element ■ o and ' are the two incoming light intensity parameters, and the proportional coefficients β and β' are solid suspensions and are not affected by the emulsifier itself. It can be regarded as a substantially equivalent amount within a short period of time.

Since they are measured, they can be considered substantially equivalent.

Since the proportionality coefficients α and α' indicate the difference in emulsifying ability corresponding to the power supplies P1 and P2, respectively, the power levels can be changed arbitrarily according to the needs of the design.

Here, when the ratio It of the transmitted light intensities 9 degrees IA(x) and IB(x) corresponding to these two optical signals Sa and sb is calculated, it can be expressed as follows from equations (1) and (2).

Therefore, if the degree of emulsification of oil based on the power supplied to the emulsifier 4 is calibrated in advance, the proportional coefficients α and α' can be grasped as known quantities.

In other words, as is clear from equation (3), as long as two types of samples with different emulsification states are prepared and the ratio of their respective transmitted light intensities is calculated, the oil concentration can be measured with the error caused by suspended solids SS removed. can be easily done.

FIG. 3 is a circuit block diagram showing the process of this calculation.

Optical signals Sa and sb given from the output of the phototube 16 in FIG. 1 are amplified by an amplifier 20 with a time difference, and a discriminator 21 discriminates whether the signal Sa or the signal sb.

That is, the power switching signal of the power source is a synchronization signal so that when the high power P1 of the power source is supplied to the emulsifier 4, the optical signal Sa corresponds to the optical signal Sa, and when the low power P2 is supplied, the optical signal sb corresponds. 22 to the discriminator 21.

On the other hand, the turbidity signal based on the optical signal Sa is sent to the hold circuit 23, and the turbidity signal based on the optical signal sb is sent to the hold circuit 24 and held.

These two held signals further pass through integrators 25 and 26, and their outputs are calculated by a ratio calculation circuit 27, and an output signal of an amount corresponding to equation (3) is sent out.

In order to directly record and indicate the oil concentration EX, it is displayed on a recorder 29 and an indicator 30 via a converter 28.

FIG. 3 is a characteristic diagram showing the relationship between the turbidity signal ratio It and the oil concentration obtained by measuring in this way.

In this case, when emulsifier 3 has a higher degree of emulsification than emulsifier 4, that is, when α>α', according to equation (3), the logarithmic conversion amount 1ogIt becomes a linear function with a positive slope. .

Therefore, it can be seen that regardless of the amount of suspended solids SS, the oil concentration can be measured as long as two emulsion samples A and B with different degrees of oil emulsification are prepared.

As described above, according to the present invention, oil-containing wastewater is taken as a sample, and two emulsified white liquids with different emulsification states of the oil in the wastewater are periodically produced from this single sample at predetermined time intervals. By calculating the ratio of the transmitted light intensities of these two samples, there is an advantage that a signal corresponding to the oil concentration from which turbidity components due to solid suspended matter have been removed can be directly obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention, Fig. 2 shows a percentage diagram showing the state of change in a sample liquid measured by the apparatus, and Fig. 3 shows an oil concentration diagram using the same apparatus. FIG. 2 is a block diagram showing a circuit configuration for measuring degrees. 1... Optical cell 2... Light source, 3...
...Phototube, 4...Emulsifier.

Claims (1)

[Claims] 1. An oil concentration measuring device that emulsifies oil-containing wastewater to form an emulsified white liquid and measures the oil concentration of the oil-containing wastewater based on a measured value of turbidity that changes depending on the degree of emulsification of this emulsified white liquid, a single optical cell; an emulsifying device for periodically supplying emulsified white liquid having different degrees of emulsification to the optical cell; a light receiving element that detects the intensity of transmitted light of the emulsified white liquid in the optical cell; Two hold circuits that hold the output of the light receiving element when the emulsified white liquid in the optical cell is at a first degree of emulsification and a second degree of emulsification, respectively, and the ratio of the hold values of each hold circuit. An oil concentration measuring device equipped with a ratio calculation circuit that calculates.