JPH0321480Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a polarographic electrical connection device having a rotating electrode, and more specifically, does not use mercury for electrical connection, thereby solving the problem of pollution prevention. This invention relates to a polarographic electrical connection device.

In a polarograph using a rotating electrode, in order to conduct the current from this rotating electrode,
It is necessary to provide electrical contacts between the rotor, which is connected to the rotating electrodes, and the stator, which is connected to the output device. Conventionally, mercury has been used as this electrical contact, and by interposing mercury between the rotor and stator, it is possible to electrically connect the rotor and stator and transmit the minute current from the rotating electrodes to the output device. It was being done. This mercury contact has good contact because mercury is liquid at room temperature, and
Electrical resistance is low and no electrical noise is generated.
Although it has excellent properties as an electrical contact, mercury is harmful to the human body, so it is difficult to measure residual chlorine in water supplies, which poses problems in terms of pollution prevention.

Recently, contacts using small spherical glass-E carbon instead of mercury have been put into practical use, but the contact resistance of these contacts increases in a short period of time, exceeding the allowable value for polarographic contacts. When used as a measuring instrument, linearity deteriorates, so short-term maintenance is required. Further, this contact point always causes minute contact failures and generates noise, which has the disadvantage of causing the reading of the measuring instrument to fluctuate.

The present invention was developed in view of the above circumstances, and it has a good electrical connection between the rotor and the stator, can reliably transmit the minute current from the rotating electrodes connected to the rotor to the output device connected to the stator, and has a low noise level. Since it does not use mercury, it is suitable for use in facilities where the use of mercury is a problem, such as measuring residual chlorine in water supplies.It also has lower noise than glass-e-carbon contacts, and is stable and maintainable over a long period of time. The purpose of the present invention is to provide a polarographic electrical connection device with good performance.

That is, in order to achieve the above object, the present invention brings a conductive stator into contact with a conductive rotor that is connected to a rotating electrode of a polarograph and rotates integrally with the rotating electrode, and also connects these rotors. Either or both of the abutting part of the stator and the abutting part of the stator are made of metal graphite.

Hereinafter, one embodiment of the present invention will be described with reference to FIG.

In the figure, 1 is a measurement cell filled with a test liquid;
A rotating electrode 2 and a reference electrode 3 are inserted into this measuring cell 1. The rotating electrode 2 is made of a conductive material such as gold or platinum, and is attached to the lower outer periphery of a mounting rod 4 made of a non-conductive material such as epoxy resin. This mounting rod 4
A screw hole 5 is bored in the center of the upper end surface, and a female screw 6 made of a conductive material such as stainless steel is screwed into the screw hole 5, and a lead wire is connected to the mounting rod 4. 7 is embedded, and the rotating electrode 2 and the female screw 6 are electrically connected via this lead wire 7. Furthermore, a screw hole 8 is bored in the center of the upper end surface of the female screw 6, and the lower end of a rotation transmission shaft 9 made of a conductive material such as stainless steel is screwed into the screw hole 8. A pulley 10 made of a non-conductive material is fixed to the outer circumference of the rotation transmission shaft 9.
A belt 14 is stretched between the motor 11 and a pulley 13 attached to the tip of the rotating shaft 12 of the motor 11. Therefore, when the motor 11 operates, its rotating shaft 12 rotates, and this rotation is transmitted to the mounting rod 4 to which the female thread 6 is attached via the pulley 13, belt 14, pulley 10, and rotation transmission shaft 9 in this order. As the attachment rod 4 rotates, the rotating electrode 2 rotates together with it.

Reference numeral 15 denotes a rotor made of a conductive material such as brass. A rod insertion hole 16 is bored in the center of the lower end surface of the rotor 15, and the upper end of the rotation transmission shaft 9 is inserted into this hole 16. At the same time, this shaft 9 is fixed to the rotor 15 by a screw 17, so that the rotor 15 rotates together with the rotation of this shaft 9. A ring-shaped recess 18 is formed at the upper end of the rotor 15, thereby forming a ring-shaped wall 19 at the outer periphery of the upper end, and a rod-shaped contact protrusion 20 at the center of the upper end.

Further, 21 is a stator, and this stator 21 is composed of an upper shaft body 22 and a lower contact body 23. This upper shaft body 22 is made of a conductor,
Its upper end passes through the through hole 25 of the holder 24 and projects upward, and one end of a lead wire 26 connected to an output device (not shown) is fixed to this projecting upper end with nuts 27, 27. At the same time, a ring-shaped flange 28 is integrally protruded from the lower outer circumference of the upper shaft body 22, and a compression coil spring 29 is interposed between the flange 28 and the holder 24.
The collar portion 28 is urged downward by the coil spring 29. Further, the lower contact body 23
has a cylindrical shape with a smaller diameter than the inner diameter of the ring-shaped wall 19 of the rotor 15, and is integrally formed of metal graphite, and is inserted into a screw hole 30 bored in the center of the upper end surface of the lower contact body 23. The lower end portions of the upper shaft body 22 are screwed together. And the lower contact body 23
The center portion of the lower end surface of the rotor 15 is pressed against the contact protrusion 20 of the rotor 15 by the biasing force of the coil spring 29.

The device configured as described above rotates the rotating electrode 2 by the operation of the motor 11, and performs polarographic measurement while rotating the rotor 15. , rotation transmission shaft 9, rotor 15,
The signal is transmitted to the output device via the stator 21 and lead wires 26 in this order. In this case, rotor 1
5 and the stator 21 are electrically connected by contacting the contact protrusion 20 of the rotor 15 and the lower contact body 23 of the stator 21, but the lower contact body 23 is made of metal graphite. Since the electrical connection is made using metallic graphite, electrical connections can be made without using toxic mercury, making polarographic measurements possible in facilities where safety is required, such as waterworks. Furthermore, the contact resistance is low, the electrical connection is good, and the noise is low.

Moreover, according to the above device, the lower contact body 23 of the stator 21 is pressed against the contact protrusion 20 by the urging force of the coil spring 29, so that the contact state of the lower contact body 23 with the connection protrusion 20 is stable. , a reliable electrical connection is made, the generation of electrical noise due to poor contact is prevented, and even if the contact portion of the lower contact body 23 against the contact protrusion 20 wears out, the biasing force of the coil spring 29 is maintained. Therefore, a reliable pressure contact state is always maintained. Furthermore, since the lower contact body 23 is in contact with the rod-shaped contact protrusion 20 of the rotor 15, noise generation is reduced from this point of view as well, and the lower contact body 23 is less likely to be worn out. Since the metallic graphite powder is collected in the ring-shaped recess 18, the device is also prevented from becoming contaminated.

In the above embodiment, the lower contact body 23 of the stator 21 is brought into contact with the rod-shaped contact protrusion 20 of the rotor 15, but the present invention is not limited to this.
Alternatively, as shown in FIG. 2, the lower part of the lower contact body 23 may be formed into a rod shape, and the rod-like protrusion 23a may be brought into contact with the upper end surface of the rotor 15 which is formed into a cylindrical shape. Further, the manner in which the lower contact body 23 (or the stator 21) contacts the rotor 15 is not limited to such a point contact, but may be a surface contact, and the stator 21 may be brought into contact with the outer peripheral portion of the rotor 15. There is no problem. Furthermore, in the above embodiment, the lower contact body 23 of the stator 21 is made of metal graphite, but the entire stator 21 is made of metal, and the contact portion of the rotor 15 with respect to the stator 21 is made of metal graphite. Alternatively, both of the mutually abutting portions of the rotor 15 and the stator 21 may be formed of metallic graphite. Furthermore, various changes may be made to other configurations without departing from the gist of the present invention.

As explained above, the present invention brings a conductive stator into contact with a conductive rotor that is connected to a rotating electrode of a polarographic device and is rotated integrally with the rotating electrode, and the contact portion of these rotors By forming either or both of the abutting parts of the rotor and stator with metal graphite, the electrical connection between the rotor and stator is good, and the minute current from the rotating electrodes can be reliably transmitted to the output device, reducing noise. It is very useful from the viewpoint of pollution prevention because it has less mercury and does not use mercury.

Hereinafter, the effects of the present invention will be specifically illustrated by experimental examples.

[Experimental Example 1] FIG. 3 is a graph showing the time-dependent change characteristics of the resistance values of contact A using glass-e-carbon and contact B using metal graphite of the present invention. Note that C is an allowable value for a polarographic contact. As is clear from the figure, the glass-E carbon contact is approximately
Although it exceeded the allowable value for polarographic contacts after 2.5 months, no change was observed in the metal graphite contacts even after 10 months of use. This proves that it far exceeds glass e-carbon in terms of stability.

[Experimental Example 2] The current-voltage curve obtained by measuring the chlorine concentration in water without a reagent using the rotating electrode type polarograph shown in the example of FIG. 1 is shown in FIG. 41. For comparison, the electrical connection device of the present invention incorporated in the rotating electrode polarograph shown in FIG.
It is shown in Figure 2.

As is clear from FIGS. 1 and 2, the current-voltage curves almost completely matched each other, confirming that the electrical connection device of the present invention has good performance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a schematic sectional view showing another embodiment of the present invention.
The figure is a graph showing the change in resistance over time for contacts using glass-E carbon and contacts using metal graphite. Figure 4 shows the case where chlorine concentration in water was measured using a metal graphite contact and a mercury contact, respectively. The current-voltage curves of FIG. 4 are those of the metal graphite contact, and FIG. 4-2 is the current-voltage curve of the mercury contact. DESCRIPTION OF SYMBOLS 1...Measurement cell, 2...Rotating electrode, 3...Reference electrode, 9...Rotation transmission shaft, 11...Motor, 15
... Rotor, 18 ... Ring-shaped recess, 19 ... Ring-shaped wall, 20 ... Contact protrusion, 21 ... Stator, 22 ... Upper shaft body, 23 ... Lower contact body, 2
9...Compression coil spring.

Claims (1)

[Scope of utility model registration request] A conductive stator is brought into contact with a conductive rotor that is connected to a rotating electrode of a polarographic device and rotated integrally with the rotating electrode, and either the contact portion of the rotor or the contact portion of the stator is brought into contact with the rotor. An electrical connection device for a polarograph, characterized in that one or both of them are made of metal graphite.