JPH0810206B2 - Rotation sensor for measurement - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotation sensor for measurement, and more particularly, to continuously measure physical or chemical properties of a slurry, a colloidal solution, a highly viscous solution, or the like. It relates to a suitable rotation sensor for measurement.

[Conventional technology]

A conventional rotary electrode is one in which an electrode is connected to a rotary driving device and rotated in a liquid to be measured to generate an electrolytic current of the liquid to be measured between a working electrode and a counter electrode. The method of measuring the concentration of solute in a solution is proportional to the concentration of the substance to be determined by making the thickness of the diffusion layer of the substance to be measured in the solution uniform.
Since it is possible to obtain a stable electrolytic current (limit diffusion current), it occupies an important position in electrochemical analysis.

As this rotating electrode, a rotating wire electrode, a rotating disk electrode, a rotating ring / disk electrode, etc. are known. These rotating electrodes require a fixed electrode as a counter electrode in addition to a rotating electrode having either a cathode or an anode as a single pole.

Ultra-micro electrodes such as micro comb-shaped electrodes are known as electrodes that can obtain a steady electrolytic current by bringing the electrolyte closer to three-dimensional diffusion without rotating the electrode or moving the solution. ing.

However, since it is necessary to obtain a uniform diffusion layer of the substance to be measured in the rotating electrode or the ultrafine electrode, it is restricted to the measurement of the sample in which the diffusion layer is easily obtained, and the slurry or the highly viscous solution in which the diffusion layer is difficult to obtain. However, there has been a problem that the concentration of the substance to be measured contained in the colloidal solution or the like cannot be accurately measured.

[Problems to be Solved by the Invention]

The present inventors have previously proposed a rotating electrode and a concentration measuring method capable of highly accurately measuring the concentration of a substance to be electrolyzed contained in a slurry, a highly viscous solution, a colloidal solution, etc. Wishhei 2-98376).

Continuously and accurately measure the physical or chemical characteristics such as the temperature, pH, concentration of the substance to be electrolyzed, etc. of the sludge substance on the belt conveyor or the slurry flowing in the groove by using the rotation sensor such as the rotating electrode. In order to do so, the sensing part (electrode part) must always come into contact with a new sample. However, when the fibrous substance coexists in the sample, there is a problem that these are entangled with the rotation sensor and hinder the rotation, and continuous accurate measurement cannot be performed.

The object of the present invention is to solve the above problems, even when a fibrous substance coexists in the sample, a slurry, a highly viscous solution,
Continuous physical or chemical properties, such as colloidal solutions
Another object of the present invention is to provide a rotation sensor for measurement that can measure accurately.

[Means for solving the problem]

The present inventors have made extensive studies in view of the above problems, and by specifying the diameter and length of the rotation sensor, prevent the fibrous substance in the sample from being entangled in the rotation sensor and enable continuous operation. The inventors have found that it is possible to reach the present invention.

The present invention is characterized in that a rotating body having a measuring sensing part at the tip, which is connected to a power source and a measuring part, has a diameter of 25 mm or more and a length of at least twice the diameter. Regarding the sensor.

By disposing a rotating electrode composed of at least one pair of a cathode and an anode, which are arranged in parallel at an interval of 1 mm or less, in the sensing part for measurement used in the present invention, electrolysis of slurry, highly viscous solution, colloidal solution, etc. It is possible to continuously measure the concentration of a substance. In addition, a thermistor, glass electrode, ion electrode (potentiometry detector), conductivity sensor, etc. are installed in the sensing part for measurement.
The temperature, pH, concentration, etc. of the sample can be continuously measured.

In the present invention, the rotation sensor having the sensing portion for measurement needs to have a diameter of 25 mm or more and a length of twice or more the above diameter. In the case of a sensor smaller than this range, when fibrous substances are present in the sample, these substances become entangled with the rotation sensor, making continuous and accurate measurement impossible. From the viewpoint of manufacturability and handleability of the sensor, the diameter of the sensor is preferably in the range of 25 to 50 mm.

FIG. 1 is a perspective view of a rotating electrode which is an example of the measuring rotation sensor of the present invention. In the figure, the rotary electrode 3 is
A pair of cathode 1 and anode 2 provided in parallel at an interval of 1 mm or less, and an insulating portion 3A for fixing the cathode 1 and the anode 2 and exposing only their tips to insulate them from other components. And a current collecting brush 5 and a power feeding ring 4 for connecting the cathode 1 and the anode 2 to a power source and a measuring unit, respectively. A noble metal such as platinum is used as a substance forming the cathode 1 and the anode 2, and carbon, copper, SUS is used as the cathode.
Etc. can also be used. For the insulating portion 3A, resins such as epoxy resin, vinyl chloride resin, phenol resin, and ceramics can be used.

The cathode 1 and the anode 2 need to be provided in parallel at intervals of 1 mm or less from the viewpoint of measurement accuracy. The closer the electrodes are, the more accurate the measurement will be.
m is preferable, and more preferably about 0.5 mm to 0.3 mm. For a uniform sample with a small amount of contaminants, it is possible to perform the measurement with higher accuracy by using electrodes with narrower intervals. At least one pair of cathode 1 and anode 2 is arranged at the tip of the rotary terminal. The greater the number of electrodes, the higher the measurement accuracy. Further, the length of the electrode is preferably short from the viewpoint of measurement accuracy, preferably 20 to 10 mm or less, and more preferably about 5 mm.

The diameter of the rotary electrode 3 is 25 mm or more, and the length thereof is twice the diameter or more. If the size of the rotating electrode is smaller than this size, when fibrous substances are present in the sample, these will be entangled with the rotating electrode and the rotation speed will not be uniform, making continuous and accurate measurement impossible.

 Hereinafter, the present invention will be described in detail with reference to Examples.

〔Example〕

In Examples 1 and 2 and Comparative Examples 1 and 2, in the dewatered sludge on the belt conveyor of the sewage treatment plant, the second
The rotation sensor 6 shown in the figure was inserted, and the water content in the dehydrated sludge was continuously measured for 24 hours, and the state of the fiber substance entangled with the rotation sensor 6 was observed.

The rotation sensor 6 has a sensing unit 7 composed of a cathode and an anode connected to a power supply unit and a measurement unit (not shown) at its tip, and is rotated by a drive unit 8. An epoxy resin was used as the material of the rotating part (insulating part) of the rotation sensor 6, and platinum electrodes of 5 mm in length and 0.5 mm in width were arranged at 1 mm intervals as electrodes of the sensing part 7.

The water content was measured by applying a voltage of 2.5 V to the electrode and using the proportional relationship between the water content and the current value. A sensor having the size shown in Table 1 was used as the rotation sensor.

In Example 1, although some sludge intruded into the drive part due to the entanglement of hair or the like after 24 hours, the water content could be continuously and favorably measured. Example 2
Then, even after 24 hours, there was no entanglement of hair or the like on the sensor, and the water content could be measured continuously and satisfactorily.

In Comparative Examples 1 and 2, the hair in the sludge became entangled with the sensor several hours after the start of measurement, and the sludge entered the drive unit, and after 24 hours, it was impossible to smoothly rotate the sensor.

From the above results, using the rotation sensor of the present invention,
It was found that stable continuous measurement was possible without the hair being entangled with the sensor even after continuous measurement for a long time.

Example 3 and Comparative Example 3 The rotating rectangular parallelepiped sensor 9 shown in FIG. 3 was inserted into a sandy sample on a belt conveyor, and changes in water content in the sample were continuously monitored by measuring conductivity. As the rotating rectangular parallelepiped sensor 9, one having a bottom surface length of 30 mm (Example 3) and one having a length of 20 mm (Comparative Example 3) were used. At the tip of the sensor 9, a conductivity measuring electrode 10 and a thermistor 11 for temperature correction are installed.

In Example 3, the variation in the measured value of the conductivity was small within 5%, but in Comparative Example 3, the fibrous substance was entangled with the sensor 9, and the variation in the measured value was as large as 15%.

From the above results, using the rotation sensor of the present invention,
It turns out that accurate measurement is possible.

〔The invention's effect〕

According to the rotation sensor for measurement of the present invention, the fibrous substance in the sample does not become entangled in the sensor, and the sensing unit installed at the tip of the sensor can always come into contact with a new sample. Further, it is possible to measure the physical or chemical characteristics of the slurry, the highly viscous solution, the colloidal solution, etc. with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view of a rotating electrode which is an example of a rotating sensor for measurement of the present invention, and FIG. 2 is an explanatory view of a rotating sensor for measurement which has an internal rotating electrode showing an embodiment of the present invention. FIG. 7 is an explanatory view of a rectangular parallelepiped rotation sensor having a conductivity measuring electrode and a thermistor built therein according to another embodiment of the present invention. 1 ... Cathode, 2 ... Anode, 3 ... Rotating electrode, 3A ... Insulating part, 4 ... Feeding link, 5 ... Current collecting brush, 6 ... Rotation sensor, 7 ... Sensing part, 8 ... Drive unit, 9 ...
Rotating rectangular parallelepiped sensor, 10 ... Electrodes for conductivity measurement, 11 ...
Thermistor.

Claims (2)

[Claims] 1. A measuring object, characterized in that the diameter of a rotating body having a measuring sensing part at the tip, which is respectively connected to a power source and a measuring part, has a diameter of 25 mm or more, and the length is twice the diameter or more. Rotation sensor. 2. The rotation sensor for measurement according to claim 1, wherein the sensing portion for measurement comprises at least one pair of a cathode and an anode arranged in parallel at an interval of 1 mm or less.