RU2307674C1 - Diving gas moisturizer - Google Patents

Abstract

FIELD: medical equipment; devices for heating and increasing moisture in diving gases, non-containing flammable anesthetics.

SUBSTANCE: moisturizer can be used at inhalation narcosis and artificial ventilation of lungs. Diving gas moisturizer has evaporation chamber with inlet and outlet branches, water heater, feeding hose, electric power source and control unit. Evaporating insertion is mounted in cavity of evaporation chamber; insertion is made in form of spiral air duct made of porous material. Evaporation chamber is made of transparent polymer material and it has metal bottom; flat water heater is mounted under bottom of chamber. Diving gas heater is disposed inside feeding hose. Temperature and humidity detectors are mounted at output of feeding hose; detectors are connected structurally. Control unit has channels for controlling temperature and humidity of diving gas and microcontroller.

EFFECT: higher efficiency of moisturizing; higher economy; safety; comfort at use.

2 dwg

Description

The invention relates to medical equipment, in particular to devices for heating and increasing the moisture content of non-flammable anesthetics of respiratory mixtures, which are given to adult patients or children with inhalation anesthesia (IN) and mechanical ventilation (IVL).

Various designs of respiratory mixture humidifiers are known (USSR copyright certificates No. 929109, A61M 16/00, 1980; 1050713, A61M 16/16, 1982; 1292787, A61M 16/00, 1985; 1570733, A61M 16 / 16, 1988).

Known humidifiers of the respiratory mixture, differing in the final structural implementation, have common characteristic significant drawbacks: the lack of means for automatically controlling the temperature and moisture content of the respiratory mixture at the outlet of the humidifier supply hose and the heating of the gas mixture passing through the humidifier by heating the water in the humidifier reservoir or feeding the mixture into the stream steam of boiling water. This requires constant monitoring by the medical staff of the outlet temperature and the amount of condensate in the delivery hose and ultimately reduces the efficiency and safety of the humidifier.

Known humidifier of the respiratory mixture given in the USSR author's certificate No. 768402 (А61М 16/16, 1978), the closest in technical essence and selected as a prototype of the patented invention.

Known humidifier provides simultaneous hydration of various sections of the respiratory tract. This is achieved by that. that the humidifier is equipped with a temperature control unit for the respiratory mixture. To increase the moisture content of the respiratory mixture in the evaporation chamber, a filler is installed in the form of a package of plates of porous material.

The use of this humidifier of respiratory mixtures in wide medical practice has revealed a number of significant structural and operational disadvantages that necessitate the improvement of the humidifier. In particular:

- the absence of a respiratory mixture heater in the supply hose and an increase in the temperature of the breathing mixture passing through the humidifier reservoir only due to heat transfer from the water in the reservoir and the plate pack makes it necessary to substantially heat the water to compensate for heat loss to the environment when the mixture passes through the supply hose, which leads to to the rapid accumulation of water condensate in the supply hose and the need (to avoid the ingress of water into the patient's lungs) of its frequent periodic removal from ialnyh water traps installed on the hose. This reduces the efficiency, safety of use of the humidifier and the convenience of its use, and the degree of heating of water in the specified humidifier requires increased energy consumption;

- an increase during operation of the flow rate of the respiratory mixture passing through the humidifier (for example, during mechanical ventilation increases the minute ventilation of the patient), can cause a temperature increase at the outlet of the supply hose that is dangerous for the patient due to the high heat capacity of the water heated in the tank.

The present invention solves the problem of improving the safety and usability of the humidifier.

The solution to this problem is achieved by a combination of new design and circuit solutions implemented in a patented humidifier.

In a humidifier of a respiratory mixture, similar to the design described in copyright certificate No. 768402, containing an evaporation chamber with an inlet and outlet pipe for the respiratory mixture, in the cavity of which there is an evaporating insert, a water heater under its bottom, a supply hose, at the outlet of which a respiratory temperature sensor is installed mixtures, an electric power source and a control unit including a channel for controlling the temperature of the respiratory mixture, according to the present invention, the evaporation chamber is made of a transparent polymer material with a metal bottom, under which a flat water heater is installed, and a spiral duct made of porous metal is installed as an evaporating insert in the chamber cavity.

The invention provides that the humidifier comprises a respiratory mixture heater located inside the supply hose, at the outlet of which a structurally combined temperature sensor of the respiratory mixture and a humidity sensor of the respiratory mixture are installed.

According to the invention, the control unit further comprises a channel for controlling the moisture content of the respiratory mixture and a microcontroller. In this case, the invention provides that the first, second and third outputs of the power source are connected respectively to the first input of the temperature control channel of the respiratory mixture, to the first input of the channel for regulating the moisture content of the respiratory mixture and the input of the microcontroller. The first output of the microcontroller is connected to the third input of the temperature control channel of the respiratory mixture, the output of which is connected to the input of the heater of the respiratory mixture, and the second input is connected to the temperature sensor of the respiratory mixture. The second output of the microprocessor is connected to the third input of the channel for regulating the moisture content of the respiratory mixture, the output of which is connected to the water heater, and the second input is connected to the humidity sensor of the respiratory mixture.

The technical result of the patented invention is as follows:

- ensuring the regulation of the moisture content of the breathing mixture allows to maintain 100% relative humidity of the breathing mixture in the entire temperature range at the outlet of the supply hose and at flows of the breathing mixture up to 50 l / min, which significantly reduces the possibility of accumulation of condensate in the supply hose, increases the efficiency of humidification and safety the patient;

- the use of a spiral duct in the evaporation chamber (tank) and its execution from a porous metal makes it possible to ensure complete saturation with moisture of the gas passing through the humidifier in the entire used flow range;

- good thermal conductivity of the spiral metal duct in contact with the water being heated allows to significantly reduce the degree of necessary heating of the water in the tank, which leads to an increase in the cost-effectiveness, safety and ease of use of the humidifier in medical practice.

The invention is illustrated by a description of an example of a constructive implementation of a patented humidifier and drawings, which show:

figure 1 is a structural diagram of a humidifier;

figure 2 is an enlarged block diagram of the algorithm of operation of the humidifier.

The patented humidifier of respiratory mixtures contains (Fig. 1) a reservoir (evaporation chamber) 1, under the bottom of which a water heater 2 is mounted. To supply the respiratory mixture to the patient, an inlet pipe 3 and an outlet pipe 4 are installed in the upper part of the tank 1, and an evaporating insert made in the form of a spiral duct 5 is installed inside the tank on the path of the respiratory mixture flow from the inlet 3 to the outlet 4 pipe.

The spiral duct 5 is made of a sheet of porous stainless steel with a thickness of 0.4-0.5 mm. The developed design of the duct 5 allows to increase the efficiency of saturation with moisture of the gas passing through the humidifier and reduce the degree of heating of the water.

The respiratory mixture humidifier contains a power supply (IP) source 14 and a control unit 6, which includes a channel 7 for controlling the temperature of the respiratory mixture (SRT), a channel 8 for regulating the moisture content of the respiratory mixture (KRV), and a microcontroller (MK) 9. The first, second, and third the outputs of IP 14 are connected respectively to the first input of the SRT, the first input of the SRT and the input of MK 9. The first and second outputs of the MK 9 are connected respectively to the third inputs of the SRT 7 and KRV 8.

The microcontroller 9, which is part of the control unit 6, can be implemented on the basis of an 8-bit microcontroller of the AVR family of the ATMEL company (USA) ATMEGA 128-16AT (see, for example, the technical documentation and the applicant’s software for the AFIN.943142.006 EZ respiratory humidifier )

Schematically, КРТ 7 and КРВ 8 can be implemented on the basis of temperature and humidity transducers (sensors) in the form of circuits that include a corresponding sensor, an amplifying part, and an analog-to-digital converter that generates digital codes of the measured temperature and humidity values received at the input of the microcontroller, which, according to a given algorithm of operation, controls the executive elements (heaters of the respiratory mixture and water).

It should be noted that specialists working in the field of anesthesia-respiratory equipment have the appropriate knowledge about the availability of diverse specific technical means for the final implementation of each node and block of respiratory mixture humidifiers. Thus, the specific technical implementation of the individual nodes and blocks of this humidifier is not difficult for specialists, since it follows from the prior art on the basis of practical data and includes well-known standard elements and components. At the same time, the technical nature of the patented humidifier of respiratory mixtures does not affect these issues, as a result of which a more detailed disclosure of all elements of the device is information redundant and inappropriate.

The channel for controlling the temperature of the respiratory mixture 7 provides a measurement of the temperature of the respiratory mixture at the outlet of the supply hose 10 in the range from 25 to 45 ° C with an error not exceeding ± 1 ° C, as well as maintaining the specified value of the temperature of the respiratory mixture with the specified error in the range from 28 to 38 ° C. The actuating element of the SRT is the respiratory mixture heater 11 made of a flexible heating wire, for example, PNKM TU16-KVO-05-89. The output of channel 7 is connected to the input of the heater 11.

The channel for regulating the moisture content of the respiratory mixture 8 ensures at the outlet of the supply hose 10 that the relative humidity of the respiratory mixture is maintained close to the saturation state (100%) over the entire range of temperatures and gas flows through the humidifier.

Sensitive converter КРВ is a humidity sensor 12, structurally combined in one unit with a temperature sensor 13 of the channel 7 for controlling the temperature of the respiratory mixture (for example, a temperature and humidity sensor SHT71 from SENSIRION, Switzerland). The output of the sensor 13 is connected to the second input of the SRT 7.

The actuating element of КРВ 8 is a flat water heater 2, heating water in the humidifier tank due to heat transfer through the metal bottom of the tank 1. The output of channel 8 is connected to the input of the water heater 2. The degree of heating of the water in the tank 1 is controlled by a humidity sensor 12 (the output of the sensor 12 is connected to the second input of the water heater), which generates a signal to turn off the water heater 2 when the moisture content of the respiratory mixture at the outlet of the supply hose 10 is reached.

The reservoir 1 of the humidifier of the respiratory mixture is made of a transparent polymeric material (for example, polycarbonate) with a metal bottom (for example, of brass).

On the side wall of the tank 1 there are marks of the maximum and minimum level of water filling.

On the front panel of the control unit 6 are located (not shown in FIG. 1): digital display of temperature values; buttons for selecting the values of the set temperature; a threshold switch of the humidity sensor 12 to maintain a relative humidity of ≈75%; mains switch with voltage on indicator; sound and visual elements of the alarm system that are triggered in violation of operating modes and in emergency situations. The visual and sound characteristics of the hazard signals comply with the requirements of GOST R ISO 9703. 1-99 and GOST R ISO 9703. 2-99 “Danger signals for anesthesia and mechanical ventilation. Parts 1 and 2. "

Humidifier respiratory mixtures works as follows.

The respiratory mixture enters the tank 1 filled with water through the inlet pipe 3, passes over the water surface through a spiral duct (evaporating insert) 5 to the outlet pipe 4 and then into the supply hose 10 connected to it.

The increase in the moisture content of the respiratory mixture entering the patient’s lungs is achieved both by increasing the temperature of the mixture as a result of its contact with the water heated in the tank 1, and by the presence of a partially immersed in the porous metal vaporizing insert 5 made in the form of a spiral duct providing increased evaporation and heat transfer from water to the passing mixture stream. Water is heated by a flat heater 2 due to heat transfer through the metal bottom of the tank 1.

The relative humidity of the breathing mixture is measured by the humidity sensor 12 entering the channel 8 of regulating the moisture content of the respiratory mixture (RCC), located at the mixture outlet from the hose 10, and converted into an electric signal. This signal, after comparison in the RCC with a threshold level corresponding to a given relative humidity (100 or 75%), is sent to the microcontroller 9 of the control unit 6, which generates a command to turn on or off the water heater 2 (figure 2), thus ensuring the maintenance of the water temperature in the tank 1 and, therefore, the evaporation rate to achieve the required level of moisture content of the respiratory mixture.

The respiratory mixture passing through the supply hose 10 is heated by a flexible heater 11. The temperature of the mixture is measured by the temperature sensor 13 entering the channel for controlling the temperature of the respiratory mixture (SRT) 7, located at the gas outlet from the supply hose 10 and structurally integrated with the humidity sensor 12. The measured temperature (in the range from 25 to 45 ° C) is converted into an electrical signal to indicate its value on a digital display. In addition, this signal, after comparing it in MCT with a threshold level corresponding to a predetermined temperature value (from 28 to 38 ° C), is fed to the microcontroller 9 of the control unit 6, which, according to the program of work, generates a command to turn on or off the flexible heater 11, ensuring temperature maintenance mixture at the outlet of the hose 10 (figure 2).

Thus, the control unit 6 provides automatic maintenance of the set values of temperature and humidity of the respiratory mixture at the outlet of the delivery hose (for the patient).

Tests of the developed humidifier for respiratory mixtures showed its high operational characteristics. Testing of the prototype humidifier confirms that the design of the humidifier provides:

- increasing the efficiency of water vapor saturation of the flow of the respiratory mixture passing through the porous spiral duct in the mass transfer chamber by increasing the evaporation surface, and the execution of the porous metal duct increases the heat transfer from the heated water to the gas stream, thereby reducing the degree of heating of water in the chamber and increasing the safety and efficiency of the humidifier;

- increased patient safety, due to the exclusion of the possibility of a dangerous increase in the temperature of the respiratory mixture at the outlet of the supply hose with a sharp change in patient ventilation;

- improving the usability of the humidifier, due to the automatic maintenance at the outlet of the hose of the state of saturation of the respiratory mixture in the entire operating range of temperatures and flows, excluding the formation of water condensate in the hose.

Claims (1)

A respiratory mixture humidifier containing an evaporation chamber with an inlet and outlet pipe for the respiratory mixture, in the cavity of which a vaporizing respiratory mixture insert is installed, a water heater under its bottom, a supply hose, at the outlet of which a respiratory mixture temperature sensor is installed, an electric power supply and a control unit including channel for regulating the temperature of the respiratory mixture, characterized in that the evaporation chamber is made of a transparent polymeric material, with a metal bottom, under which is installed flat a water heater, and a spiral duct made of porous metal is installed in the chamber cavity as an evaporating liner of the breathing mixture, the humidifier contains a breathing mixture heater located inside the supply hose, at the outlet of which the structurally combined temperature sensor of the respiratory mixture and the humidity sensor of the breathing mixture are installed, and the control unit further comprises a channel for regulating the moisture content of the respiratory mixture and a microcontroller, with the first, second and third outputs the power supply points are connected respectively to the first input of the respiratory mixture temperature control channel, to the first input of the respiratory mixture moisture control channel and the microcontroller input, the first output of the microcontroller is connected to the third input of the respiratory mixture temperature control channel, the output of which is connected to the input of the respiratory mixture heater, and the second input connected to the temperature sensor of the respiratory mixture, the second output of the microcontroller is connected to the third input of the moisture control channel the content of the respiratory mixture, the output of which is connected to the water heater, and the second input is connected to the humidity sensor of the respiratory mixture.

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