Patent Description:
Automatic ventilation devices designed to regulate or assist ventilation by connecting to users' respiratory tracts are widely used in medical practice, which include respiratory assistance devices to be used for continuous positive airway pressure therapy (nasal CPAP), a treatment for sleep apnea syndrome.

Continuously feeding a dry gas to a user's respiratory tract can cause discomfort to the user, and in some cases can even trigger damage to the respiratory tract. Therefore, the respiratory assistance device is connected to a humidification device that adds moisture to a feed gas.

Conventional humidification devices used in respiratory assistance devices usually adopt a method in which a heating element (heater plate) heats an entire body of water in a reservoir and vaporizes the water (see, for example, <CIT>, Japanese Translation No. <CIT>).

<FIG> illustrates a schematic diagram of a conventional respiratory assistance device <NUM>. The respiratory assistance device <NUM> includes a humidification device <NUM> that utilizes a heating and vaporization method. The humidification device <NUM> takes in a feed gas fed from a ventilator <NUM> through a feed gas inlet <NUM>, heats and humidifies the feed gas, and sends out the feed gas through a feed gas outlet <NUM> to an inspiratory side respiratory circuit <NUM>. The feed gas is fed through a hose <NUM> from an interface <NUM> to a user U. Expiratory air is released to the outside through an expiratory side respiratory circuit <NUM>.

<FIG> is an explanatory view of the conventional humidification device <NUM>. The humidification device <NUM> stores liquid (water) <NUM> inside a case. The liquid (water) <NUM> is heated and vaporized by a heating element <NUM>. The heating element <NUM> has, for example, an electric resistance element (not illustrated), and is heated by the application of electric current from a power supply <NUM>.

More specifically, the feed gas flowing from the feed gas inlet <NUM> contains water vapor which has been vaporized from a surface of the liquid (water) <NUM> within a humidification space <NUM>. After being humidified, the feed gas is sent from the feed gas outlet <NUM> through the respiratory circuit to the respiratory tract of the user U. At this time, the outlet temperature of the feed gas is measured by a feed gas outlet temperature measurement unit <NUM>, and power which is to be inputted to the heating element <NUM> is controlled so that appropriate temperature and humidity are achieved in the respiratory tract of the user U.

Furthermore, <CIT> discloses a humidifier comprising a controller which is configured to determine an ambient humidity, calculate an amount of liquid to be added to the flow of breathable gas based on the determined ambient humidity and the target humidity, calculate an amount of energy required to vaporize the amount of liquid, and control the water supply unit to deliver the amount of liquid to the porous heating element.

However, in the technology described in <CIT>, the temperature of the water in the entire reservoir must be increased to generate a sufficient amount of water vapor. Therefore, energy consumption is high and the time necessary until humidification becomes possible is lengthened. It is also difficult to reduce the size of the device because a large amount of hot water has to be stored. In addition, since a large amount of hot water needs to be stored, there is a great risk of the hot water leaking when the humidification device tips over, resulting in scald to the user or the like. In the future, the respiratory assistance devices are expected to be used more often in home medical care, and in such cases, it is inconvenient for family members other than medical personnel to handle such devices.

The present invention was made in consideration of the above-described problems, and an object thereof is to provide a humidification device that can be made smaller in size and lighter in weight, and that can quickly and sufficiently humidify a gas without heating an entire body of water to be stored, as well as a respiratory assistance device.

According to the invention this object is achieved by humidification device according to claim <NUM> and a humidification method according to claim <NUM>. Further features and advantageous modifications are shown in the dependent claims.

According to the present invention, it is possible to achieve extremely excellent effects of enabling high-speed heating and humidification control and humidification control with minimum liquid supply, by independently performing controlling the input power by referring to the temperature in the respiratory circuit connected to the humidification device, calculating the target input power, as a target, corresponding to the target heated and humidified state of the feed gas, and controlling the supply amount of the liquid on the basis of the difference value between the input power and the target input power.

According to the invention, since the liquid (water) can be supplied to the heating unit only in an amount required for heating and humidification, it is possible to eliminate the accumulation of the liquid water and prevent bacterial growth, which achieves the excellent effect of providing a humidification device which is also excellent.

According to the invention, it is possible to achieve the excellent effect of enabling to provide a respiratory assistance device including the compact and lightweight humidification device that can perform quick heating and humidification with a minimum amount of liquid (water amount) and an optimum input power.

(<NUM>) The present invention also provides a respiratory assistance method including the humidification method described in the claims.

In this regard, it is possible to achieve extremely excellent effects of enabling high-speed heating and humidification control and humidification control with a minimum liquid supply, by independently performing controlling the input power by referring to the temperature in the respiratory circuit connected to the humidification device, calculating the target input power, as a target, corresponding to the target heated and humidified state of the feed gas, and controlling the liquid supply unit on the basis of the difference value between the input power and the target input power. Advantageous Effects of Invention.

The humidification device, the respiratory assistance device, and the humidification method according to claims <NUM> to <NUM> of the present invention have beneficial effects of realizing a humidification device that is easy to perform maintenance, hygienic, compact in size, light in weight, and capable of quick heating and humidification, and a respiratory assistance device including such a humidification device. Brief Description of Drawings.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

<FIG> illustrate an example of the embodiment of the present invention, and the identical reference numerals indicate the same objects in the drawings. In each figure, part of the configuration is omitted, as appropriate, to simplify the drawings. The size, shape, thickness, and the like of the members are exaggerated as appropriate.

<FIG> is a schematic diagram of a respiratory assistance device <NUM> according to the embodiment of the present invention. The respiratory assistance device <NUM>, which assists respiration of a user U, includes a blower <NUM> configured to send out a feed gas, a medical gas cylinder <NUM> configured to supply a medical gas to be used for medical treatment or the like, a humidification device <NUM> configured to humidify the feed gas, a respiratory circuit <NUM> configured to lead the feed gas to the user U, and an interface <NUM> for respiratory assistance, placed near the nose and/or oral cavity of the user U, that is configured to lead the feed gas.

The blower <NUM> draws air from an inlet <NUM> and feeds the air into a humidification device <NUM>. The medical gas supplied from the medical gas cylinder <NUM> is also fed into the humidification device <NUM>. In other words, the feed gas may be a mixed gas of the air drawn from the inlet <NUM> and the medical gas.

The medical gas may be an oxygen gas, for example.

The humidification device <NUM> has a case <NUM>, a power supply <NUM>, an input power measurement unit <NUM> configured to measure an input power to be inputted from the power supply <NUM> to a heating unit (metal porous body) <NUM> (see <FIG>, which will be described later), a liquid supply device <NUM> configured to supply a liquid (water) to the heating unit (metal porous body) <NUM>, an outside environmental variable measurement unit <NUM> configured to measure environmental variables of an environment where the user is present, and a control device <NUM> configured to control the humidification device <NUM>. At a feed gas outlet <NUM> to which the feed gas is sent out from the case <NUM> (see <FIG>, which will be described later), a feed gas outlet temperature measurement unit <NUM> configured to measure the temperature of the feed gas to be sent to the respiratory circuit <NUM> is disposed.

The location of this "outlet" is not specifically limited, and may be located anywhere downstream from the heating unit (metal porous body) <NUM>.

The power which is to be inputted from the power supply <NUM> is to be directly sent to a coil <NUM>, but the electric energy is inputted to the heating unit (metal porous body) <NUM> (see <FIG>, which will be described later) through an electromagnetic induction phenomenon, and so the above-mentioned expression is adopted. Therefore, the input power measurement unit <NUM> may measure either the power which is to be inputted to the coil <NUM> or the energy which is to be transferred to the heating unit (metal porous body) <NUM>.

The heating unit <NUM> is a metal porous body with a porous structure containing metal. The heating unit (metal porous body) <NUM> may have a mesh structure made of pressed metal fibers.

The control device <NUM> includes a heating control unit <NUM> configured to control the input power by referring to a temperature within the humidification device <NUM> or within the respiratory circuit <NUM> connected to the humidification device <NUM>, a target input power calculation unit <NUM> configured to calculate a target input power, as a target, corresponding to a target heated and humidified state of the feed gas, and a liquid supply control unit <NUM> configured to control the amount of liquid (see <FIG>, which will be described later) on the basis of a difference value between the measured input power and the target input power.

The outside environmental variable measurement unit <NUM> has an outside temperature measurement unit <NUM> configured to measure the temperature of an environment in which the respiratory assistance device <NUM> is installed, and an outside humidity measurement unit <NUM> configured to measure the humidity of the environment in which the respiratory assistance device <NUM> is installed. The outside temperature measurement unit <NUM> may be, for example, a resistance thermometer. The outside humidity measurement unit <NUM> may be, for example, a bimetal type, or a digital type hygrometer which uses a moisture sensing agent and comb electrodes.

The control device <NUM> is constituted of a CPU, a RAM, a ROM, and the like, and performs various types of control. The CPU is a so-called central processing unit, and executes various programs to realize various functions. The RAM is used as a work area and a storage area for the CPU, and the ROM stores an operating system and the programs to be executed by the CPU.

The control device <NUM> may control the operation of the entire respiratory assistance device <NUM>.

<FIG> is an explanatory view of the inside of the case <NUM> of the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention. The case <NUM> has a feed gas inlet <NUM> into which the feed gas is fed, the feed gas outlet <NUM> through which the feed gas is sent out to the respiratory circuit <NUM> (see <FIG>), the coil <NUM> configured to generate a magnetic field, the heating unit (metal porous body) <NUM>, an insulating unit <NUM> configured to provide electrical insulation between the coil <NUM> and the heating unit (metal porous body) <NUM>, a ferrite <NUM> which is a magnetic body configured to increase efficiency of magnetic coupling between the coil <NUM> and the heating unit (metal porous body) <NUM>, and a rectifying plate <NUM> configured to change a flow of the feed gas so that the feed gas is brought into contact with the heating unit (metal porous body) <NUM> for a sufficient length of time. The feed gas is heated and humidified by a flow of heated vapor which is generated in the heating unit (metal porous body) <NUM> and transferred into a humidification space <NUM>.

<FIG> is a cross-sectional view of the humidification device <NUM>. The feed gas is taken into the case <NUM> from the feed gas inlet <NUM>, and the flow of the feed gas is altered by the rectifying plate <NUM>. Then, the feed gas travels along, for example, a humidifying and heating path <NUM> as illustrated by a dashed line in <FIG>, which specifically includes an entry side path 50A from the feed gas inlet <NUM> to the heating unit (metal porous body) <NUM>, a heating body side path 50B in the vicinity of the heating unit (metal porous body) <NUM>, and an outlet side path 50C from the heating unit (metal porous body) <NUM> to the feed gas outlet <NUM>. The feed gas is heated and humidified in the humidification space <NUM>, by introduction of the heated vapor generated in the heating unit (metal porous body) <NUM>, and is thereafter sent through the feed gas outlet <NUM> to the respiratory circuit <NUM>.

The humidification device <NUM> includes the case <NUM> which contains the humidification space <NUM> in which the water vapor is introduced to the feed gas to be fed to the user U. The heating unit <NUM>, the coil <NUM>, and the insulating unit <NUM> are disposed in the humidification space <NUM>. In addition, there is a liquid supply unit <NUM> (see <FIG>, which will be described later) that supplies a liquid, to be vaporized and made into the water vapor, to the heating unit <NUM>.

Specifically, the heating unit (metal porous body) <NUM> has a cylindrical shape with a perfect circular cross section. The heating unit (metal porous body) <NUM> contains metal and has electrical conductivity as a whole, while having sufficient electrical resistance so as to generate heat when electric current induced by electromagnetic induction from the coil <NUM> flows therethrough. The coil <NUM> is made of a metal wire wound in a spiral shape and is disposed along the outer periphery of the ferrite <NUM>. The coil <NUM> has high electrical conductivity. The insulating unit <NUM> is disposed between the heating unit (metal porous body) <NUM> and the coil <NUM> to electrically insulate the heating unit (metal porous body) <NUM> and the coil <NUM> from each other. The insulating unit <NUM> also serves as an isolation wall that spatially isolates the coil <NUM> from the liquid (water) supplied from the liquid supply device <NUM> to the heating unit (metal porous body) <NUM> and the vapor from the liquid. The insulating unit <NUM> may be made of glass or a synthetic resin.

The coil <NUM> is disposed in the inner periphery of the heating unit <NUM> via the insulating unit <NUM>.

The insulating unit <NUM> has a cylindrical shape, and is disposed on an inner peripheral side of the heating unit <NUM>, where the coil <NUM> is disposed on an inner peripheral side of the insulating unit <NUM>.

The heating unit <NUM> may be disposed such that a central axis of the cylindrical shape of the heating unit <NUM> is oriented in a non-vertical direction. An aspect in which the central axis is horizontal is described here as a basic posture, but the advantage of this humidification device is that humidification and heating can be performed even when the posture is changed.

<FIG> is an explanatory view of the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention.

In this variation, the ferrite <NUM> is provided on the inner peripheral side of the coil <NUM> to increase the magnetic coupling between the heating unit (metal porous body) <NUM> and the coil <NUM>. Part of the case <NUM> may perform the function of the insulating unit <NUM> (see <FIG>, as described above). The case <NUM> may be made of a synthetic resin, such as an ABS resin, for example.

The input power to the coil <NUM> is applied from the power supply <NUM> through a power supply line <NUM>. The power supply <NUM> is controlled by the heating control unit <NUM>. The value of the power being applied is measured in real time by the input power measurement unit.

The liquid (water) is supplied from the liquid supply device <NUM> to the heating unit (metal porous body) <NUM>. Specifically, the liquid (water) is supplied from a liquid storage unit <NUM> through the liquid supply unit <NUM> to the heating unit (metal porous body) <NUM>. The liquid (water) is supplied gradually from an end of the liquid supply unit <NUM> to an inner peripheral surface of the heating unit (metal porous body) <NUM>. The liquid supply unit <NUM> is tubular, and it is desirable that the end of the liquid supply unit <NUM> is disposed along the inner peripheral surface of the heating unit (metal porous body) <NUM>. A supply amount of the liquid (water) is regulated by a liquid supply amount regulation unit <NUM>, which may be, for example, a piezoelectric pump. The liquid supply amount regulation unit <NUM> is controlled by the liquid supply control unit <NUM> (see <FIG>).

The liquid supply unit <NUM> supplies the liquid so as to maintain a state in which the liquid does not accumulate in the vicinity of the heating unit <NUM>. That is, the liquid is supplied to the extent not exceeding a maximum amount of the liquid that can be vaporized by the heating unit (metal porous body) <NUM>.

<FIG> is an explanatory view illustrating an operation of separating an energy supply unit <NUM> and a humidification unit <NUM> that constitute the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention. While in a state of heating and humidifying, the energy supply unit <NUM> including the ferrite <NUM> and the coil <NUM> is disposed in a recess of the case <NUM>, which contains the heating unit (metal porous body) <NUM> therein, and the coil <NUM> and the heating unit (metal porous body) <NUM> together form a magnetic circuit to enable heating of the heating unit (metal porous body) <NUM> by an electromagnetic induction phenomenon (see the left drawing of <FIG>). In the case of performing maintenance, specifically in the case of replacing the humidification unit <NUM> having the heating unit (metal porous body) <NUM> with a new one, the energy supply unit <NUM> and the humidification unit <NUM> can be spatially separated (see the right drawing of <FIG>).

<FIG> is an explanatory view illustrating an operation of opening the humidification space <NUM> in the case <NUM> and separating only the humidification unit <NUM> (heating unit (metal porous body) <NUM>). The humidification device <NUM> has a main unit 30A and a lid unit 30B. During maintenance, specifically in the case of replacing the heating unit (metal porous body) <NUM> with a new one, the lid unit 30B is opened to easily remove and replace the heating unit (metal porous body) <NUM> with a new one (see the right drawing of <FIG>).

<FIG> is an explanatory view of a humidification device <NUM> of a respiratory assistance device <NUM> according to a first variation of the present invention.

In this variation, in order to close a magnetic circuit between a heating unit (metal porous body) <NUM> and a coil <NUM> as much as possible and increase magnetic coupling, a U-shaped ferrite <NUM> is provided. Part of a case <NUM> may perform the function of an insulating unit <NUM> (see <FIG>, as described above). The case <NUM> may be made of a synthetic resin, such as an ABS resin, for example.

An input power to the coil <NUM> is applied from a power supply <NUM> through a power supply line <NUM>. The power supply <NUM> is controlled by a heating control unit <NUM>. The value of the power being applied is measured in real time by an input power measurement unit.

A liquid (water) is supplied from a liquid storage unit <NUM> through a liquid supply unit <NUM> to the heating unit (metal porous body) <NUM>. The supply amount of the liquid (water) is controlled by a liquid supply amount regulation unit <NUM>, which may be, for example, a piezoelectric pump. The liquid supply amount regulation unit <NUM> is controlled by a liquid supply control unit <NUM> (see <FIG>).

The liquid supply unit <NUM> supplies the liquid so as to maintain a state in which the liquid does not accumulate in the vicinity of the heating unit <NUM>. The supply of the liquid to the heating unit (metal porous body) <NUM> is the same as in the case of <FIG>, and hence a description therefor will be omitted.

<FIG> is an explanatory view illustrating an operation of separating an energy supply unit <NUM> and a humidification unit <NUM> that constitute the humidification device <NUM> in the respiratory assistance device <NUM> according to the first variation of the present invention. In a state of heating and humidifying, the energy supply unit <NUM> including the ferrite <NUM> and the coil <NUM> is disposed in a recess of the case <NUM>, which contains the heating unit (metal porous body) <NUM> therein, and the coil <NUM> and the heating unit (metal porous body) <NUM> together form the magnetic circuit to enable heating of the heating unit (metal porous body) <NUM> by an electromagnetic induction phenomenon (see the left drawing of <FIG>). In the case of performing maintenance, specifically in the case of replacing the humidification unit <NUM> having the heating unit (metal porous body) <NUM> with a new one, the energy supply unit <NUM> and the humidification unit <NUM> can be spatially separated (see the right drawing of <FIG>).

Since the liquid (water) is supplied to the humidification unit <NUM>, bacteria may occur and accordingly periodic replacement is desirable. Since the case <NUM> can be easily separated into the energy supply unit <NUM> and the humidification unit <NUM>, replacement of just the humidification unit <NUM> with a new one is possible, which makes maintenance easy.

<FIG> is an explanatory view of an inside of a case <NUM> of a humidification device <NUM> in a respiratory assistance device <NUM> according to a second variation of the present invention. In this variation, a warming unit <NUM> which contains a heating unit (metal porous body) <NUM>, and a humidification unit <NUM> which contains another heating unit (metal porous body) <NUM> similarly are provided. A feed gas introduced from a feed gas inlet <NUM> is heated by the warming unit <NUM> to which no liquid is supplied, and is humidified by the humidification unit <NUM> to which a liquid is supplied. After that, the feed gas is sent out through a feed gas outlet <NUM> to a respiratory circuit <NUM> (see <FIG>). The supply of the liquid in the humidification unit <NUM> is the same as in the embodiment of the present invention, and so a detailed description will be omitted.

<FIG> is a cross-sectional view of the case of the humidification device <NUM>. The warming unit <NUM> includes a warming coil <NUM> and a warming heating unit <NUM>. The humidification unit <NUM> includes a humidification coil <NUM> and a humidification heating unit <NUM>. The warming unit <NUM> may be controlled according to an algorithm illustrated in <FIG>, which will be described later, and the humidification unit <NUM> may be controlled according to algorithms illustrated in <FIG> and <FIG>, which will be described later.

This variation has the effect of enabling control of temperature and humidity independently.

In this variation, the warming unit <NUM> is located upstream and the humidification unit <NUM> is located downstream of the gas supply, but to the contrary, the humidification unit <NUM> may be located upstream and the warming unit <NUM> may be located downstream of the gas supply.

In addition, the liquid may be supplied to the warming unit <NUM> as well as to the humidification unit <NUM>, so that the warming unit <NUM> may simultaneously heat and humidify the feed gas along with the humidification unit <NUM>.

In general, in the respiratory assistance device <NUM>, it is desirable that the feed gas to be sent into the nasal and oral cavities of the user U have temperatures and relative humidity values determined in advance by a doctor, for example, a temperature of <NUM> and a relative humidity of <NUM>%. However, when the feed gas has achieved the above-described determined values at the feed gas outlet <NUM> of the humidification device <NUM>, the temperature of the feed gas decreases due to heat loss as well as relative humidity, while the feed gas is being sent through the respiratory circuit <NUM>. The degree of heat loss varies depending on an environmental temperature.

Therefore, it is necessary to calculate a target temperature and a target humidity (target absolute humidity) of the feed gas at the feed gas outlet <NUM> by taking into account environmental variables of an environment in which the respiratory assistance device <NUM> is placed, i.e., an outside temperature, an outside humidity, and the degree of heat loss in the respiratory circuit <NUM>, and to determine the input power from the power supply <NUM> and the supply amount of the liquid (water) so as to achieve the target temperature and the target humidity.

Here, in the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, the target input power calculation unit <NUM> calculates the target input power by taking into account power required to vaporize water in the heating unit (metal porous body) <NUM> when the water required to achieve the target absolute humidity is supplied.

Specifically, the humidification device <NUM> in the respiratory assistance device <NUM> according to this embodiment is a humidification device configured to humidify a feed gas to be fed to a user U. The humidification device <NUM> includes the heating unit <NUM> configured to heat and vaporize a liquid to be used for humidifying the feed gas, the liquid supply unit <NUM> configured to supply the liquid to the heating unit <NUM>, the power supply <NUM> configured to supply energy to the heating unit <NUM>, the input power measurement unit <NUM> configured to measure an input power to be inputted from the power supply <NUM> to the heating unit <NUM>, the heating control unit <NUM> configured to control the input power by referring to a temperature in the humidification device <NUM> or in the respiratory circuit <NUM> connected to the humidification device <NUM>, the target input power calculation unit <NUM> configured to calculate a target input power, as a target, corresponding to the target heated and humidified state of the feed gas, and the liquid supply control unit <NUM> configured to control a supply amount of the liquid on the basis of a difference value between the measured input power and the target input power.

The humidification device <NUM> in the respiratory assistance device <NUM> according to this embodiment includes the outside temperature measurement unit <NUM> configured to measure an outside temperature which is the temperature of an environment in which the user U is present, the outside humidity measurement unit <NUM> configured to measure an outside humidity which is the humidity of the environment in which the user U is present, and the feed gas outlet temperature measurement unit <NUM> provided in the vicinity of the feed gas outlet <NUM> which is an outlet of the feed gas to be sent to the respiratory circuit <NUM> (see <FIG>), the geed gas outlet temperature measurement unit being configured to measure a feed gas outlet temperature which is the temperature of the feed gas to be sent to the respiratory circuit <NUM>. Here, the heating control unit <NUM> controls the input power to the heating unit <NUM> on the basis of a difference value between the outlet temperature and a preset target temperature, and the target input power calculation unit <NUM> calculates the target input power on the basis of the values of the outside temperature, the outside humidity, and the outlet temperature.

Furthermore, in the humidification device <NUM> in the respiratory assistance device <NUM> according to this embodiment, the liquid supply control unit <NUM> controls the supply amount of the liquid to the heating unit <NUM> from the liquid supply amount control unit <NUM>, which varies the supply amount of the liquid.

<FIG> is a flowchart that explains an algorithm for controlling the feed gas outlet temperature of the feed gas in the humidification device <NUM> in the respiratory assistance device <NUM>.

First, a feed gas outlet temperature (hereinafter abbreviated as "outlet temperature") is measured by the feed gas outlet temperature measurement unit <NUM> (see <FIG>) disposed at the feed gas outlet <NUM> of the humidification device <NUM> (step S1). Whether there is a difference between the outlet temperature and a target temperature that is calculated and set in advance is determined (step S2). In a case where there is no difference, the heating control unit <NUM> (see <FIG>) controls to maintain an input power to be measured by the input power measurement unit <NUM> (see <FIG>) (step S6). In a case where there is a difference, whether the outlet temperature is higher than the target temperature that is calculated and set in advance is determined (step S3). In a case where the outlet temperature is higher than the target temperature, the heating control unit <NUM> controls to decrease the input power (Step S4). In a case where the outlet temperature is lower than the target temperature, the heating control unit <NUM> controls to increase the input power (step S5). After completing the above-described steps S4, S5, and S6, the operation returns to the step S1.

Through the above-described feedback control, the input power is always controlled so that the feed gas outlet temperature remains stable at the target temperature.

The control of the input power by the heating control unit <NUM> may be PID control that controls, for example, a current value. It is desirable that the specific power control be PWM control.

<FIG> is a flowchart that explains an algorithm for calculating and setting a current target input power in real time in the humidification device in the respiratory assistance device.

First, an outside temperature is measured by the outside temperature measurement unit <NUM> (see <FIG>), and an outside humidity is measured by the outside humidity measurement unit <NUM> (see <FIG>). Then, an absolute humidity, which is a target at the feed gas outlet <NUM>, is determined on the basis of the outside temperature, the outside humidity, a flow rate of the feed gas, a heat loss of the respiratory circuit, and the like (step U1). Next, the amount of water required to achieve this absolute humidity is calculated, and a target input power to be applied from the power supply <NUM> to the heating unit (metal porous body) <NUM> to increase the temperature of the amount of water and vaporize the amount of water and, in addition, to increase the temperature of the flowing feed gas is calculated (step U2). The calculated value is then set as a current target input power (step U3). This current target input power is used in an algorithm illustrated in <FIG>, which will be described later.

By constantly regressing the above-described operation, an optimum target input power can be calculated and set in real time.

<FIG> is a flowchart that explains an algorithm for controlling the amount of liquid (water) to be supplied from the power supply <NUM> to the heating unit <NUM>.

First, an input power to the heating unit (metal porous body) <NUM> is measured by the input power measurement unit <NUM> (step T1). Next, whether there is a difference between the current input power and a current target input power is determined (step T2). In a case where there is no difference, the liquid supply control unit <NUM> controls the liquid supply amount regulation unit <NUM> (see <FIG>) to maintain a supply amount of the liquid (step T6). In a case where there is a difference, whether the value of the current input power is larger than the current target input power calculated and set in advance is determined (step T3). In a case where the value of the current input power is larger than the current target input power, the liquid supply control unit <NUM> controls the liquid supply amount regulation unit <NUM> to decrease the supply amount of the liquid (step T4). In a case where the value of the current input power is smaller than the current target input power, the liquid supply control unit <NUM> controls the liquid supply amount regulation unit <NUM> to increase the supply amount of the liquid (step T5). After completing the above-described steps T4, T5, and T6, the operation returns to step T1.

As a result of the above-described feedback control of the supply amount of the liquid, the input power is controlled to stabilize at the target input power.

In the humidification device <NUM> in the respiratory assistance device <NUM> according to this embodiment, the control illustrated in <FIG> and the control illustrated in <FIG> are performed independently.

In the control of the humidification device <NUM> in the respiratory assistance device <NUM> according to the present invention illustrated in <FIG>, the input power of the power supply <NUM> is determined only by the temperature control based on the feed gas outlet temperature at the feed gas outlet <NUM>. Thus, the input power is controlled to compensate for a drop in the outlet temperature that occurs when the liquid (water) is supplied. On the other hand, the target input power is updated in real time on the basis of the outside environment, the flow rate of the feed gas, the outlet temperature, and the like, and the supply amount of the liquid is controlled so that the actual input power becomes the actual target input power. That is, the feature of this algorithm is that it does not directly control the input power for humidification.

The humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention can be configured to spatially separate the humidification unit <NUM> configured to vaporize the liquid (water) into water vapor, i.e., the heating unit <NUM>, and the energy supply unit <NUM> configured to supply the energy to the heating unit <NUM>, i.e., the coil <NUM>. Therefore, since only the humidification unit <NUM>, which contains moisture and may cause problems such as easy generation of bacteria, can be replaced with a new one, it is possible to achieve the excellent effect of facilitating maintenance.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the liquid (water) does not accumulate inside the humidification device <NUM>, it is possible to achieve the excellent effect of making it easier to maintain a good hygiene condition with less chance of bacterial growth.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the coil <NUM>, which applies energy to the heating unit <NUM> using the electromagnetic induction phenomenon, and the heating unit <NUM> are electrically insulated by the insulating unit <NUM>, it is possible to achieve the excellent effect of reducing the possibility of an accident such as a short circuit.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the coil <NUM> is disposed inside the cylindrical heating unit <NUM>, it is possible to achieve the excellent effect of efficiently providing the energy from the coil <NUM> to the heating unit <NUM> using the electromagnetic induction phenomenon.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since it is easy to increase the surface area in which the heating unit <NUM> comes into contact with the feed gas to be heated and humidified, it is possible to achieve the excellent effect of providing the humidification device <NUM> that is compact in size and is capable of sufficient heating and humidification.

The metal porous body has electrical conductivity. According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, it is possible to achieve the excellent effect of generating resistive heat by a flow of electric current through the metal porous body <NUM> from the coil <NUM> by the electromagnetic induction phenomenon and thus efficiently vaporizing water.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the coil and the heating unit <NUM> through which the electric current flows by electromagnetic induction are efficiently magnetically coupled with each other, it is possible to achieve the excellent effect of increasing energy transfer efficiency from the coil <NUM> to the heating unit <NUM>.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, it is possible to achieve the remarkably excellent effects of enabling the humidification device to be small in size and light in weight, and enabling quick and sufficient humidification without heating an entire body of water to be stored.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, it is possible to achieve extremely excellent effects of enabling high-speed heating and humidification control and humidification control with a minimum liquid supply, by independently performing controlling the input power by referring to the temperature in the respiratory circuit <NUM> connected to the humidification device <NUM>, calculating the target input power, as a target, corresponding to the target heated and humidified state of the feed gas, and controlling the liquid supply amount regulation unit <NUM> on the basis of the difference value between the input power and the target input power.

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the input power to the heating unit <NUM> is determined on the basis of environmental variables of the environment in which the user U is present, it is possible to achieve the excellent effect of enabling quick and sufficient heating and humidification with minimum amounts of energy and liquid (water amount).

According to the humidification device <NUM> in the respiratory assistance device <NUM> according to the embodiment of the present invention, since the liquid (water) can be supplied to the heating unit <NUM> only in an amount required for heating and humidification, it is possible to eliminate the accumulation of the liquid water and prevent bacterial growth, which achieves the excellent effect of providing the humidification device which is also excellent in hygienic aspect.

According to the respiratory assistance device <NUM> according to the embodiment of the present invention, it is possible to achieve the excellent effect of enabling to provide the respiratory assistance device including the compact and lightweight humidification device <NUM> that can perform quick heating and humidification with the minimum amount of liquid (water amount) and the optimum input power.

Claim 1:
A humidification device (<NUM>) configured to humidify a feed gas to be fed to a user (U), the humidification device (<NUM>) comprising:
a heating unit (<NUM>) configured to heat and vaporize a liquid to be used for humidifying the feed gas;
a liquid supply unit (<NUM>) configured to supply the liquid to the heating unit (<NUM>);
a power supply (<NUM>) configured to supply energy to the heating unit (<NUM>); and
an input power measurement unit (<NUM>) configured to measure an input power to be inputted from the power supply (<NUM>) to the heating unit (<NUM>),
characterized by
a heating control unit (<NUM>) configured to control the input power by referring to a temperature of the feed gas in the humidification device (<NUM>) or in a respiratory circuit (<NUM>) connected to the humidification device (<NUM>);
a target input power calculation unit (<NUM>) configured to calculate a target input power, as a target, corresponding to a target heated and humidified state of the feed gas; and
a liquid supply control unit (<NUM>) configured to decrease a supply amount of the liquid when the measured input power is greater than the target input power and increase the supply amount of the liquid when the measured input power is less than the target input power.