JPS6360857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water quality meter for measuring turbidity, MLSS (activated sludge concentration), organic pollution, etc. used in water supply plants or sewage treatment plants.

FIG. 1 is a sectional view showing an example of a conventional optical turbidity meter. In the figure, 1 is the liquid to be measured, 2 is the light source, 3 is a lens for converting the light beam ○a from the light source 2 into a parallel beam ○b, and 4 is the light beam ○a from the light source 2 that passes through the liquid to be measured 1 The first to receive the transmitted light
The photocell 5 is a second photocell that monitors the light intensity of the light source 2. 6 is a computing unit that performs predetermined computing processing using the outputs X and Y of the first and second photocells 4 and 5 and sends out a turbidity proportional signal Z;
is the measuring tube.

The operation of the turbidity meter configured as described above is as follows. The light beam ○a from the light source 2 placed at the focal position of the lens 3 becomes a parallel light beam ○b and enters the liquid to be measured 1. The parallel light beams (○) and (b) are absorbed or scattered by the turbidity component of the liquid to be measured 1. The output X of the first photocell 4, which detects the transmitted light ○, is expressed by the following equation according to the Lambert-Beer law.

X=Y exp [−εlx] …(1) Here, Y is the light intensity of light source 2, and ε is the measured liquid 1.
, l is the measurement length of the liquid to be measured 1, and x is the turbidity. From equation (1), turbidity x is expressed as follows.

x=1/εl·l _o Y/X (2) Here, since the extinction coefficient ε and the measurement length l do not normally change, they are set as a constant C. The turbidity proportional value Z is determined from the output X of the first photocell 4 and the output Y of the second photocell 5 that monitors the light intensity of the light source 2 as follows.

Z=C·l _o Y/X (3) The calculator 6 performs the calculation shown in equation (3) and outputs the turbidity proportional value Z. As mentioned above, with conventional turbidity meters, if the measurement length is fixed, the measurement dynamic range becomes narrower, so it is necessary to prepare multiple measurement tubes with different measurement lengths, and it is also necessary to obtain measurement tubes to replace them. It had drawbacks such as being time consuming.

The present invention was made to solve the above-mentioned drawbacks, and an object of the present invention is to obtain a turbidity meter whose measurement length can be freely changed.

The present invention has been made to achieve the above-mentioned objects, and it is possible to measure the turbidity and MLSS of a measured object using the transmittance of light or ultrasonic waves passing through the measured object.
In water quality meters that measure activated sludge concentration, organic pollution, etc., an elastic part is installed in a part of the measurement tube that samples the object to be measured, and the elastic part is deformed by external force to adjust the measurement length of the liquid to be measured. The present invention provides an ice quality meter characterized by the ability to The present invention will be explained below using the drawings.

FIGS. 2a and 2b are sectional views each showing an embodiment of the present invention. The components from the liquid to be measured 1 to the second photocell 5 are the same as those described above. 7a
8 is a measuring tube in which a part of the tube is made of elastic material A such as rubber; 8 is a light source 2, a lens 3, and a second tube;
This is a light source head equipped with a photocell 5. Note that 9 is a motor for moving the light source head 8, and 10 is a position detector that generates an electrical output corresponding to the position of the light source head 8. 11 inputs the outputs X and Y of the first and second photocells 4 and 5 and the output L of the position detector 10, performs predetermined arithmetic processing, and generates a turbidity proportional value Z and a control signal for the motor 9. It is a computing device.

The operation of the present invention configured as described above will be explained as follows. The light beam ○a from the light source 2 is converted into a parallel light beam ○b by the lens 3 and is irradiated onto the liquid to be measured 1. In this case, as described above, the output of the first photocell 4 that detects the amount of transmission of the parallel light beam ◯◯ is expressed by the relational expression shown in equation (1). However, in the present invention, a part of the measuring tube 7a is made of material A such as elastic rubber, and by pressing the light source head 8 against the part made of material A, the measurement length is adjusted as the light source head 8 moves. l
can be changed. The movement of the light source head 8, that is, the adjustment of the measurement length l, is performed by controlling the motor 9 using the computing unit 11 so that the output X of the first photocell 4 is always within a proper range.

FIG. 2a shows a case where the turbidity of the liquid 1 to be measured is low, and the measurement length _l1 is made longer by retracting the light source head 8. FIG. 2b shows a case where the turbidity of the liquid to be measured 1 is high, and the measurement length _l2 is shortened by the advancement of the light source head 8. The position detector 10 sends a proportional value L to the measurement length l from the position of the light source head 8 to the calculator 11. Arithmetic unit 11
inputs the above L and the outputs X and Y of the first and second photocells 4 and 5, calculates and outputs the turbidity proportional value Z using the following formula.

Z=C/L·l _o Y/X (4) In this way, a turbidity meter with variable measurement length l is obtained.

In the above embodiments, a turbidity meter has been described, but the same applies to a MLSS meter, a water quality meter for organic pollution, etc., or a smoke concentration meter, etc., in which the effect of the measurement length occurs. Further, the present invention can be applied not only to an optical method but also to an ultrasonic method. Furthermore, the light source head may be fixed and either the first photocell side or both may be moved, and the movement method is not limited to the motor.

As described above, according to the present invention, the dynamic range of measurement is expanded, the S/N of the detection signal is improved, the output is stabilized, and other effects can be achieved through implementation.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional turbidimeter, and FIGS. 2a and 2b are sectional views showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Liquid to be measured, 2... Light source, 4... First photocell, 5... Second photocell, 7, 7a... Measuring tube,
8...Light source head, 9...Motor, 10...Position detector, 11...Arithmetic unit.

Claims (1)

[Scope of Claims] 1. A water quality meter that measures the turbidity, MLSS (activated sludge concentration), organic pollution, etc. of a liquid to be measured based on the transmittance of light or ultrasound transmitted through the liquid to be measured,
A water quality meter characterized in that a part of the measuring tube for sampling the liquid to be measured is provided with an elastic part having elasticity, and the elastic part is deformed by an external force to adjust the measurement length of the liquid to be measured. . 2. As a means of deforming the elastic part, a motor that applies an external force to the elastic part is controlled so that the transmitted signal from the liquid to be measured falls within a certain range, and a turbidity proportional value is obtained from a relational expression including the measurement length. A water quality meter according to claim 1, characterized in that the water quality meter is configured as follows.