RU188887U1 - DEVICE FOR LOW-TEMPERATURE PLASMA GENERATION - Google Patents

Abstract

The proposed solution relates to medical technology, in particular to devices generating a low-temperature plasma jet, which can be connected to endoscopic probes via a technological channel. The main goal of the proposed technical solution is to ensure patient safety during the treatment of internal organs. The following goal is to increase the reliability of all elements of the endoscope, which is also important for patient safety. The goal is achieved by the fact that in the inventive device the electrodes are installed in the endoscope technological channel, made in the form of a pair of metal rings placed sequentially on a glass tube and connected to the unit voltage control through a resonant circuit, step-up transformer and transmission line. In this case, the voltage control unit is made in the form of an inverter, and the step-up transformer is assembled on a ferrite core. In addition, the transmission line is made in the form of a shielded cable. The low-temperature plasma generation device includes: voltage control unit 1, which rectifies and stabilizes an alternating mains voltage and is made in the form of a semiconductor inverter 2. The latter converts a DC voltage to an alternating high-frequency and has a control circuit 3. This circuit 3 generates the control pulses of the transistors of the inverter 2. Block 4 consists of inductors and capacitors, which in our case form a series resonant circuit. Step-up transformer 5 is assembled on a ferrite core and has a transformation ratio of 10. Transmission line 6 is a shielded, for example, coaxial cable up to 3 m long. Electrode system 7 of the low-temperature plasma jet source includes a pair of electrodes that are made in the form of metal rings, in series placed on a glass tube. The latter simultaneously performs the role of a nozzle and a dielectric barrier. Similar constructive execution of electrodes and their installation in the process channel can significantly improve patient safety, since there is no direct contact of the electrode-nozzle with the gas. In addition, the electrode, which plays the role of a dielectric barrier, can significantly limit the current that can touch the patient's body. The use of voltage pulses of microsecond duration and high porosity allows to obtain a low gas temperature plasma jet with a low level of flow of the working gas. This effect is achieved due to short current pulses, which limits the development of gas discharge contraction, and the presence of an extended pause between pulses ensures relaxation of the discharge plasma. When using a harmonic voltage in the electrode system, long duration currents occur, contributing to the development of gas discharge contraction and an increase in the electron and gas temperature of the plasma jet.

Description

The proposed solution relates to medical technology, in particular, to devices that generate a low-temperature plasma jet, which can be connected to endoscopic probes through a technological channel, and can be used in non-drug treatment of certain gastrointestinal diseases.

Recently, endoscopic probes have been mainly used for in vivo diagnostic studies.

For example: "A method of obtaining an image of an object, a device for its implementation and a device for delivering low-coherence optical radiation", RF patent for IZ No. 2242710, IPC G01B 9/02, G02B 26/08, declared 07.06.2002, publ. 02.20.2004; "A device for obtaining images during endoscopic studies", RF patent for PM No. 50793, IPC AV 1/05, Appl. September 23, 2005, publ. 01/27/2006; "Video endoscope and set of video endoscopes", patent for the Federal Law of the Russian Federation No. 2526948, IPC AV 1/00, AV 1/05, Appl. 06/19/2013, publ. 08.27.2014.

As mentioned above, all of the above devices are intended mainly for diagnostic studies.

Currently, endoscopic probes are also used to process and treat the inner surface of the stomach and intestines. For these purposes, the probes are equipped with video cameras and technological channels with a diameter of, for example, 2-2.5 mm. At the same time, the channels of endoscopes can be used to attach various types of tools, for example, a scalpel, a manipulator, a coagulator, etc. More often, cold plasma is used to process and treat the internal surfaces of the stomach and intestines. This direction can be judged by the following sources: "The working part of a portable surgical device for ultrasonic dissection and plasma coagulation of biological tissues", RF patent for PM No. 171480, IPC AV 18/04, AV 17/32, Appl. 08/04/2016, publ. 06/01/2017; "A portable surgical device for ultrasonic dissection and plasma coagulation of biological tissues", RF patent for PM No. 171481, IPC AV 18/04, AV 17/32, Appl. 08/04/2016, publ. 06/01/2017.

The disadvantages of the above devices include the following: an arc discharge plasma is used, which has a high gas temperature for coagulation (sintering) of the treated tissue, which is unacceptable for therapy of the inner surface of the stomach.

Also known "Plasma source", a patent for the IZ of the Russian Federation No. 2415522, IPC H05N 1/24, Appl. 09.11.2006, published on 27.03.2011.

The disadvantages of this plasma source include, in our opinion, the following: since there is no dielectric barrier between the high voltage electrode and the living tissue being processed, there is a possibility of a current leakage from the high voltage electrode to the human body, which reduces the electrical safety of the device.

The closest in technical essence and the achieved result is "Device for generating low-temperature plasma", RF patent for PM No. 167645, IPC H05H 1/24, Appl. 12/02/2015, publ. 01/10/2017. This device can serve as a prototype. It includes: a voltage control unit, a power generator, a high-voltage transformer, a pair of electrodes, an ionization chamber, a gas mixture forming device, a magnetic and electrical effect device, a nozzle at the mixture output from the chamber.

The disadvantages of the above device, taken as a prototype, include its limited capabilities (it can only handle external surfaces), structural complexity (the presence of magnetic and electrical effects, the device forming a gas mixture, and its low electrical safety due to possible leakage of current from the high voltage electrode on the human body.

The main goal of the proposed technical solution is to ensure patient safety, as well as to ensure the possibility of treating internal organs. A passing goal is to increase the reliability of all elements of the endoscope, which is also important for patient safety. The problem is that for painless cold plasma therapy of the stomach it is necessary to ensure the generation and delivery through the endoscope of a gas-discharge plasma with a gas temperature not higher than 40 ° C. To date, the task of generating cold plasma using an external electrode system and transporting plasma flows inside the technological channel of the endoscope is not feasible. Therefore, the authors suggested using an electrode system built into the technological channel at the end of the endoscope, and supplying high voltage to power the electrode system via a shielded cable (for example, coaxial).

This goal is achieved by the fact that in a device containing an endoscope with a technological channel, a voltage control unit, a transformer, a pair of electrodes, a transmission line and a nozzle at the exit of a plasma jet, the electrodes are installed in the technological channel, made in the form of a pair of metal rings placed sequentially on glass tube acting as a nozzle and a dielectric barrier, and connected to the control unit voltage through a resonant circuit, step-up transformer and transmission line, which is made in the form of a screen nirovannogo cable.

In addition, the voltage control unit is made in the form of an inverter, and the step-up transformer is assembled on a ferrite core.

Such a constructive implementation of the electrodes and their installation in the technological channel can significantly improve patient safety, since there is no direct contact of the electrode-nozzle with the gas. In addition, the electrode, which acts as a dielectric barrier, can significantly limit the current that can touch the patient's body.

The use of voltage pulses of microsecond duration and high porosity allows to obtain a low gas temperature plasma jet with a low level of flow of the working gas. This effect is achieved due to short current pulses, which limits the development of gas discharge contraction, and the presence of an extended pause between pulses ensures relaxation of the discharge plasma. When using a harmonic voltage in the electrode system, long duration currents occur, contributing to the development of a gas discharge contraction and an increase in the electron and gas temperature of the plasma jet.

Since the transmission line has a shielded grounded braid, the high-frequency interference emitted by the pulse generator is minimized, and the transmission of high voltage over a shielded cable is more electrical than a non-shielded cable. Therefore, to ensure patient safety and operability of all elements of the endoscope, high voltage supplying the electrode system must be supplied through shielded, for example, coaxial cable up to 3 m long. harmonious form, and it is used to form low-temperature plasma flows. On the other hand, shielded cable, like any other similar line, is a significant load for short-pulse voltage. In order to realize a pause in the current through the electrode system, the power supply circuit forms periodically repeating bursts of harmonic pulses. This is necessary to enable high-voltage transmission over a coaxial line with low losses. This solution allows not only to achieve a better matching of the AC voltage source with the load in the form of a long line and electrode system, but also to realize the inclusion of the power transistors of the converter at zero current, as a result of which the switching losses of the inverter are significantly reduced.

The essence of the technical solution is illustrated by drawings, where:

FIG. 1 shows the voltage pulse diagrams;

FIG. 2 is a block diagram of a low temperature plasma generation device.

The device for generating low-temperature plasma includes: a constant voltage source 1, which rectifies and stabilizes an alternating mains voltage. A semiconductor inverter 2 converts a DC voltage into an alternating high frequency. The inverter control circuit 3 generates the control pulses of the inverter 2 transistors. Unit 4 consists of inductors and capacitors, which can form resonant circuits with different circuits. For our case, the preferred scheme of the serial resonant circuit. Step-up transformer 5 is assembled on a ferrite core and has a transformation ratio of 10. Transmission line 6 is a shielded (coaxial) cable up to 3 m long. Electrode system 7 of the low-temperature plasma jet source includes a pair of ring metal electrodes placed on a glass tube that performs the role of the nozzle and the dielectric barrier.

The operation of the device is as follows:

When the inverter 2 is fed from a DC voltage source 1, harmonic oscillations are excited in the resonant oscillatory circuit 4. In this case, the oscillating circuit 4 is loaded onto the step-up transformer 5, the secondary winding of which is connected to the electrode system 7 via line 6. Thus, a high-voltage harmonic voltage of one period with pauses is applied to the electrodes. Line 6 is an additional capacitance, which is also involved in the resonant oscillatory process. After oscillations in the oscillating circuit, circuit 3 prohibits the operation of the inverter. Oscillations in the resonant circuit 4 stop, as well as on the electrodes of the lamp. In this case, the excitation of the gas also ceases, as a result of which the plasma relaxes in the gas-discharge gap. After a pause, Inverter 2 starts up again, and the whole process repeats. As a result, bundles of harmonic oscillations appear on the electrodes with pauses between the bundles, as shown in FIG. 1. Since line 6 has a grounded shielding braid, high-frequency interference emitted by the pulse generator is minimized, and high voltage transmission is more secure.

Claims (3)

1. The device for generating low-temperature plasma, containing an endoscope with a process channel, a voltage control unit, a transformer, a pair of electrodes, a transmission line and a nozzle at the plasma jet exit, characterized in that the electrodes are installed in the process channel, made in the form of a pair of metal rings placed sequentially on a glass tube that acts as a nozzle and a dielectric barrier, and is connected to a voltage control unit through a resonant circuit that boosts a transformer and a transmission line that Paradise is made in the form of shielded cable. 2. The device for generating low-temperature plasma according to claim. 1, characterized in that the voltage control unit is designed as an inverter. 3. A device for generating low-temperature plasma according to claim. 1, characterized in that the step-up transformer is assembled on a ferrite core.

Images