| US3980542A | 1976-09-14 | |||
| GB2108675A | 1983-05-18 | |||
| US5310470A | 1994-05-10 | |||
| US4450064A | 1984-05-22 | |||
| US4847980A | 1989-07-18 | |||
| GB2123965A | 1984-02-08 |
| 1. | Electrodeconstruc; on for coaxial, Electrochemical sensors made of metal, described by the following : the L/D proportion between the length of the sensor (L) and its outer diameter (D) is between 05. |
| 2. | Mounting of the Electro chemical sensor included in article 1. into pinlike electrodes according to Figure 1. described by the following : the coaxial sensor (2, 3,4,5,) and the outputs (12,13) are electrically insulated from the outer tube plate (1). |
| 3. | Mounting g of the coaxial, Electro chemical sensor included in article 1. according to Figure 1.3. described by the following : an electrically insulating extension (8,9) is mechanically attached to one end of the sensor (2, 3, 50 sticking, casting etc. |
| 4. | Sensors included in article, 1.. 2.. 3. described by the following the outputs (12, 13, 7,10) are not coaxial. |
Electro-chemical sensors occupy a fairly big area of technical life and can be classified according to their application, formation and major characteristics. A book by Dr. Vitán Gábor and Hegyessy Grörgy# Modern in-vivo Electro- chemical Sensors" (Medicina Könyvkiadó, Budapest 1985.) includes a high standard and comprehensive study on electro-chemical sensors. The description of : 1 GOI2C11I'IC . C : 1'OC-Ol7. S : lilC : 1011 : l. t'fo. ? OLI11C ll. l : Il-. IIL111gari111 Ptt ; Ili 206610, as well as in the earlier Patent 176787.
A concentric electrode used in medical diagnostics and therapy is described in ths US Patent 3060923 which can be used in electromyography. A similarly- structured electrode is described in the US Patent 3083706 as well.
Our aim with this invention is to introduce a new solution which can eliminate a significant disadvantage of formerly introduced inventions. Basically, the most significant disadvantage of all the previous inventions is, that the outer tube is not only for the sake of mechanical stability, but the outer tube plate serves as one of the electrodes as well. It is a major disadvantage regarding the accuracy of measuring.
According to our experiments, when measuring, the signal level emitted by the <BR> <BR> coaxial electrode depends on the depths of piercing substantially, therefore the disturbance and the signal level shall become the same order of magnitude. At pin-like coaxial electrodes it may cause a difference of hundreds of percentages.
At pointless electrodes it may reach 50 percent.
According to the solution offered by the invention, we separated the bearer (1) and the sensors insulating from the tube plate, cast with an electrically insulating synthetic rosin.
By limiting the L/D proportion between the length of the sensors (L) and the outer diameter (D) of the tube plate between 0-5, by which sensors become similar to discs, the harmful effect causing the inaccuracy shall cease to exist.
The point of a specially designed pin-electrode can be seen in figure 1, 2 in side and top view. Similar formation of pointless electrodes can be seen in figure 3.
The L/D proportion must be adhered to as well, even though the mechanical bearer is a plastic polypropylene tube. The long outer metal tube as one of the <BR> <BR> electrodes ; regardless of the fact whether it touches the electrolyte directly or only through the plastic tube plate does not change the signal level shift.
Inaccuracy may be traced here as well.
Based on the following design patterns we shall introduce the basic principles of the invention : Figure 1. Vertical section of the mounting of hypodermic needle shaped coaxial electrode Figure 2. Top view of-the same needle Figure 3. Vertical and front view of a pointless electrode Figure shows the mounting of a ing of a coaxial electrode-construction in the point of a rust-proof steel needle, where it is clearly visible, that the rust-proof needle (1) is insulated (11) from the coaxial sensor with synthetic rosin. The outer electrode of the coaxial sensor (2) and the central electrode (4,5) is electrically insulated (3). The output of the central electrode (12) and the output (13) of the outer cr°ocf fi ccr°c a°crll al tt orcJt. : ?, /'Itc centr°crl elct. °oc : (, 5).
This parallel configuration prevents asymmetric signal shift in the vertical direction of the tube.
In pointless probes, only outputs (7,10) arranged into the similar parallel configuration may be applied.
Since stabile mechanical fixing of the coaxial sensor cannot be implemented in pointless electrodes without the appropriate length of the sensor cage, therefore an extension (8) made of electrically insulating material is to be cast to the end of the sensor.
This electrically insulating extension (9) has the same role when mounting a coaxial sensor into a hypodermic needle.
The operation of coaxial sensors shall be described in details as follows : The alkali ion content of the electrolyte Na + and K-forms a galvanic cell between the outer and the inner electrode (2,4,5). The galvanic cell is short- circuited through an ammeter, this way the current of the galvanic cell exclusively depends on the concentration of the alkali ion.
Since we realised, that the outer electrode (2) of the coaxial electrode pair causes current shi. depending on its length, it was reduced to the shortest length that may be sufficient to eliminate the disturbance. This ensures the highest possible accuracynecessary for measuring.