CN111150911A

CN111150911A - CPAP system and CPAP device

Info

Publication number: CN111150911A
Application number: CN201911104790.7A
Authority: CN
Inventors: 远藤洋一
Original assignee: Seiko Instruments Inc
Current assignee: Seiko Instruments Inc
Priority date: 2018-11-08
Filing date: 2019-11-08
Publication date: 2020-05-15
Also published as: JP2020074970A

Abstract

The present invention improves the dyspnea condition of a patient using CPAP. A CPAP system is provided with: a fan that sucks in and sends out air; a sensor for measuring the pressure or flow rate of air sent by the fan; a housing having a fan and a sensor built therein, and having an air inlet through which air sent to the fan flows in and an air outlet through which air sent from the fan flows out; a motor drive unit that controls the rotation speed of the fan based on the pressure or flow rate measured by the sensor; a valve that adjusts the pressure or flow rate of air supplied from the air outlet port to a mask attached to a patient via a tube; and a valve driving unit that opens and closes the valve based on the pressure measured by the sensor.

Description

CPAP system and CPAP device

Technical Field

The present invention relates to a CPAP (Continuous Positive Airway Pressure) system and a CPAP apparatus.

Background

CPAP is a treatment for preventing apnea during sleep by mechanically sending pressurized air from the nose to the airway to open the airway. CPAP is an effective treatment for sleep apnea syndrome.

CPAP systems deliver air under pressure from the nose to the airway. The CPAP system is composed of a CPAP device that sends air out, a tube that sends air at a preset pressure, and a mask that touches the nose.

Patients with sleep apnea syndrome wear a mask during sleep. The pressure level may be set by a doctor in accordance with the condition of the patient in two modes, i.e., a mode in which the pressure is always kept constant and a mode in which the pressure is automatically increased in accordance with the time of apnea.

As a CPAP apparatus, a technique is known that can accurately detect the pressure of air to be detected (for example, see patent document 1). In this technique, a pressure sensor is provided in the CPAP apparatus, has a first port through which air discharged from a discharge port of the CPAP apparatus is guided, and a second port that is an open port, and detects the pressure of the air discharged from the discharge port. The opening is provided in a housing of the CPAP apparatus and communicates with the outside of the CPAP apparatus. The tube connects the opening portion with the second port of the pressure sensor.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-78997.

Disclosure of Invention

Problems to be solved by the invention

CPAP devices are controlled to deliver air under pressure from the nose to the airway when the patient breathes in air and to drop the pressure when the patient breathes out air. However, when the patient exhales air, the control for lowering the pressure may not be performed in time. In this case, the patient sometimes has difficulty breathing because excess air is continuously supplied to the patient while the air is exhaled.

The present invention has been made in view of such circumstances, and an object thereof is to provide a CPAP system and a CPAP apparatus capable of improving the condition of dyspnea in a patient using CPAP.

Means for solving the problems

(1) In view of the above problem, a CPAP system according to an aspect of the present invention includes: a fan that sucks in and sends out air; a sensor for measuring the pressure or flow rate of the air sent by the fan; a housing in which the fan and the sensor are installed, the housing having an air inlet through which air sent into the fan flows in and an air outlet through which air sent out from the fan flows out; a motor drive unit that controls the rotation speed of the fan based on the pressure or the flow rate measured by the sensor; a valve for adjusting the pressure or flow rate of air supplied from the air outlet to a mask attached to a patient via a tube; and a valve driving unit that opens and closes the valve based on the pressure or the flow rate measured by the sensor.

(2) In the CPAP system according to one aspect of the present invention, the motor driving unit may control the rotation speed of the fan based on a PWM signal, and the valve driving unit may open and close the valve based on the PWM signal.

(3) In the CPAP system according to one aspect of the present invention, the valve driving unit may close the valve when the duty ratio of the PWM signal is equal to or greater than a threshold value, and open the valve when the duty ratio of the PWM signal is less than the threshold value.

(4) In the CPAP system according to one aspect of the present invention, the valve driving unit may open and close the valve based on a voltage signal obtained by converting the PWM signal into a voltage.

(5) In the CPAP system according to one aspect of the present invention, the valve driving unit may close the valve when the voltage is equal to or lower than a first voltage threshold value, and open the valve when the voltage is equal to or higher than a second voltage threshold value that exceeds the first voltage threshold value, based on the voltage signal.

(6) A CPAP device according to an aspect of the present invention includes: a fan that sucks in and sends out air; a sensor for measuring the pressure or flow rate of the air sent by the fan; a housing in which the fan and the sensor are installed, the housing having an air inlet through which air sent into the fan flows in and an air outlet through which air sent out from the fan flows out; a motor drive unit that controls the rotation speed of the fan based on the pressure or the flow rate measured by the sensor; a valve for adjusting the pressure or flow rate of air supplied from the air outlet to a mask attached to a patient via a tube; and a valve driving unit that opens and closes the valve based on the pressure or the flow rate measured by the sensor.

Effects of the invention

According to the present invention, a CPAP system and a CPAP apparatus capable of improving the condition of dyspnea in a patient using CPAP can be provided.

Drawings

FIG. 1 is a diagram illustrating one example of a CPAP system of an embodiment of the present invention;

fig. 2 is a diagram showing an example of characteristics showing a relationship between a flow rate of air sent from the CPAP apparatus and a static pressure, with a rotation speed of a fan as a parameter;

fig. 3 is a diagram showing one example of a characteristic diagram representing response time;

FIG. 4 is a diagram showing one example of a CPAP apparatus of an embodiment of the present invention;

fig. 5 is a diagram showing one example of a PWM signal;

FIG. 6 is a graph illustrating one example of a characteristic diagram representing response time of a CPAP system of an embodiment of the present invention;

FIG. 7 is a flow chart showing one example of the actions of a CPAP system of an embodiment of the present invention;

fig. 8 is a diagram showing an example of a CPAP device according to a first modification of the embodiment of the present invention;

fig. 9 is a flowchart showing an example of the operation of the CPAP system according to the first modification of the embodiment of the present invention;

fig. 10 is a diagram showing an example of a CPAP apparatus according to a second modification of the embodiment of the present invention;

fig. 11 is a flowchart showing an example of the operation of a CPAP system according to a second modification of the embodiment of the present invention;

fig. 12 is a diagram showing an example of a CPAP apparatus according to a third modification of the embodiment of the present invention;

fig. 13 is a flowchart showing an example of the operation of the CPAP system according to the third modification of the embodiment of the present invention.

Detailed Description

Next, the CPAP system and the CPAP apparatus according to the present embodiment will be described simultaneously with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the embodiment described below.

In addition, "based on XX" in this application means "based on at least XX", and includes a case where the "is based on other elements in addition to XX". Further, "based on XX" is not limited to the case of directly using XX, and includes a case of performing an operation or processing on XX. "XX" is any element (e.g., any information).

(embodiment mode)

Embodiments according to the present invention will be described below with reference to the drawings. In some cases, components having the same function or similar functions are denoted by the same reference numerals, and redundant description thereof will be omitted.

(overview of CPAP System)

Fig. 1 is a diagram illustrating one example of a CPAP system of an embodiment of the present invention.

The CPAP system 100 includes a CPAP device 200, a tube 300, and a mask 400.

The CPAP device 200 includes: a housing having an air inflow port through which air flows in and an air outflow port through which air flows out; a fan; a pressure sensor; and a valve 250. The fan and the pressure sensor are built in the housing.

The fan draws air into the CPAP device 200 from the air inlet and delivers the drawn air to the tube 300 connected to the air outlet of the CPAP device 200.

The pressure sensor measures the pressure of the air sent by the fan to the CPAP device 200.

The valve 250 regulates the pressure of the air supplied from the air outflow port to the mask 400 via the tube 300.

The tube 300 is connected to an air outlet of the CPAP device 200 and sends air sent by the fan to the mask 400.

The mask 400 is connected to the tube 300 and is fitted to the patient. The mask 400 delivers air delivered by the CPAP device 200.

Fig. 2 is a diagram showing an example of characteristics showing a relationship between a flow rate of air sent by the CPAP apparatus and a static pressure, with a rotation speed of the fan as a parameter. In fig. 2, the horizontal axis represents the flow rate [ slpm ] of air delivered from the CPAP apparatus 200, and the vertical axis represents the pressure [ kPa ].

Fig. 2 shows the case where the fan rotation speed is changed to 2000r/min, 3000 r/min, 3500 r/min, and 4000 r/min. As the rotation speed of the fan becomes higher, the obtained pressure (static pressure) becomes higher.

In fig. 2, an example of the used region is shown by a one-dot chain line. As used herein, a region is represented by a range of flow rates and a range of pressures. Specifically, the flow rate used is in the range of about 10[ slpm ] to 130[ slpm ], and the pressure used is in the range of about 0.1[ kPa ] to 4.7[ kPa ].

The pressure achieved with a flow rate of air delivered by the CPAP apparatus 200 of 20 to 100 slpm and a fan speed of 2000r/min is around 0.75 to 1.2 kPa. Pressures of around 1.75 kPa to 2.5 kPa are obtained with a flow rate of air delivered by the CPAP device 200 of 20 to 120 slpm and a fan speed of 3000 r/min. The pressure achieved with a CPAP apparatus 200 delivering air at a flow rate of 20 to 140 slpm and a fan speed of 3500 r/min is around 2.7 to 3.5 kPa. Pressures of around 3.7 kPa to 4.5 kPa are obtained with a flow rate of air delivered by the CPAP apparatus 200 of 20 to 120 slpm and a fan speed of 4000 r/min.

Here, a case will be described where the pressure is adjusted between 0.5 kPa and 2.5 kPa by adjusting the rotation speed of the fan between 2000r/min and 3500 r/min, assuming that the flow rate is 125 slpm. That is, when the patient breathes in air, the rotational speed of the fan is increased from 2000[ r/min ] to 3500[ r/min ] to send the air to which pressure is applied from the nose to the respiratory tract, and when the patient breathes out air, the rotational speed of the fan is decreased from 3500[ r/min ] to 2000[ r/min ] to drop the pressure.

Fig. 3 is a diagram showing an example of a characteristic diagram representing a response time. In the example shown in fig. 3, one example of a response time is shown in the case where: the pressure was adjusted between 0.5 kPa and 2.5 kPa by adjusting the fan speed between 2000r/min and 3500 r/min at a flow rate of 125 slpm.

The time required to increase the rotational speed of the fan from 2000r/min to 3500 r/min is taken as the rotational speed increase response time T1, and the time required to decrease the rotational speed of the fan from 35000 r/min to 20000 r/min is taken as the rotational speed decrease response time T2. The fan is rotated by a DC motor. In the DC motor, the fall time for decreasing the rotation speed is slow relative to the rise time for increasing the rotation speed. Therefore, the rotation speed increase response time T1 is shorter than the rotation speed decrease response time T2.

When the pressure of the air supplied from the air outlet to the mask 400 via the tube 300 is not adjusted by the valve 250, the rotation speed of the fan is reduced from 3500 r/min to 2000r/min to reduce the pressure even when the patient exhales the air, and the rotation speed reduction response time T2 is long, so that the pressure reduction is slow and the pressure reduction takes time. Since the pressure drop takes time, when the patient exhales air, the pressure remains and air that exerts a pressure exceeding that necessary continues to be supplied. Therefore, the patient sometimes has difficulty breathing.

Then, with the CPAP system 100 of the embodiment, when the patient exhales air, the pressure of the air supplied from the air outflow port to the mask 400 via the tube 300 is adjusted by opening the valve 250. By configuring in this way, when the patient exhales air, the pressure of the air on the patient can be reduced, and the situation of difficulty in breathing of the patient can be improved.

The CPAP device 200 included in the CPAP system 100 will be described in detail below.

Fig. 4 is a diagram showing an example of a CPAP apparatus according to the embodiment of the present invention. As shown in fig. 4, the CPAP device 200 includes a fan 210, a pressure sensor 220, a motor 230, a motor drive unit 240, a valve 250, a valve drive unit 260, and a housing 270.

The fan 210 is incorporated in the casing 270, sucks air from the air inflow port AI of the casing 270, and sends out the sucked air to the air outflow port AO.

The pressure sensor 220 is built in the housing 270, and periodically measures the pressure of the air sent by the fan 210. The pressure sensor 220 periodically outputs the measurement result of the air pressure to the motor drive unit 240 and the valve drive unit 260.

The motor 230 is connected to the fan 210, and rotates the fan 210 based on information indicating the number of rotations output by the motor driving unit 240.

The motor drive unit 240 obtains the measurement result of the pressure of the air output from the pressure sensor 220. The motor drive unit 240 determines the rotation speed set in the motor 230 based on the obtained measurement result of the pressure of the air. The motor driving unit 240 outputs information indicating the rotation speed to the motor 230 based on the determined rotation speed.

Fig. 5 is a diagram showing an example of information indicating the rotation speed. One example of the information indicating the rotation speed output by the motor driving unit 240 is a PWM (Pulse Width Modulation) signal. In fig. 5, the vertical axis represents voltage, and the horizontal axis represents time.

The motor drive unit 240 increases a duty ratio, which is a ratio of a time during which the PWM signal is on to a period during which the PWM signal is repeatedly on and off, when the measurement result of the pressure of air decreases due to the patient inhaling air, based on the acquired measurement result of the pressure of air. With such a configuration, the rotation speed of the fan 210 can be increased, and therefore, air pressurized for a patient who breathes in air can be sent to the respiratory tract through the nose.

On the other hand, the motor drive unit 240 decreases the duty ratio when the measurement result of the air pressure increases due to the patient exhaling the air based on the acquired measurement result of the air pressure. With such a configuration, the rotation speed of the fan 210 can be reduced, and thus the pressure of the air supplied to the mask 400 can be reduced for the patient who exhales the air. In fig. 5, an example of decreasing the duty ratio after increasing the duty ratio is shown. The description is continued with returning to fig. 4.

The valve 250 is built into the housing 270 and regulates the pressure of the air supplied from the air outlet AO via a tube 300 connected to the air outlet AO to a mask 400 fitted to the patient PA. One example of valve 250 is a solenoid valve, a linear valve, a waste gate valve. Specifically, the valve 250 opens and closes the valve 250 in accordance with the control performed by the valve driving unit 260, thereby adjusting the pressure of the air supplied from the air outlet AO to the mask 400 attached to the patient PA via the tube 300.

The valve driving unit 260 obtains the measurement result of the pressure of the air output from the pressure sensor 220. The valve driving unit 260 opens and closes the valve 250 based on the obtained measurement result of the pressure of the air. Specifically, when the obtained measurement result of the pressure of the air is smaller than the previous measurement result and is equal to or smaller than the first pressure threshold value, the valve driving unit 260 performs control to close the valve 250. Here, the case where the measurement result of the pressure of the air is lower than the previous time and equal to or lower than the first pressure threshold value includes a case where the pressure is reduced due to the patient inhaling the air. In this way, when the pressure is reduced by the patient inhaling the air, the valve driving unit 260 closes the valve 250, so that the air does not flow out from the valve 250, and thus the pressure drop can be prevented.

On the other hand, when the obtained measurement result of the pressure of the air is greater than the previous time and is equal to or greater than the second pressure threshold value, the valve driving unit 260 performs control to open the valve 250. The second pressure threshold is higher than the first pressure threshold. Here, the case where the measurement result of the pressure of the air is higher than the previous time and is equal to or higher than the second pressure threshold value includes a case where the pressure is increased due to the exhalation of the air by the patient. In this way, when the pressure increases due to the patient exhaling air, the valve driving unit 260 opens the valve 250, so that air flows out from the valve 250, and the pressure can be reduced.

Fig. 6 is a diagram showing an example of a characteristic diagram showing a response time of the CPAP system according to the embodiment of the present invention. In the example shown in fig. 6, as in the example shown in fig. 3, one example of response time in the case where: the pressure was adjusted between 0.5 kPa and 2.5 kPa by adjusting the fan speed between 2000r/min and 3500 r/min at a flow rate of 125 slpm.

As compared with fig. 3, it is understood that the rotation speed increase response time T1 is the same degree, but the rotation speed decrease response time T2 is shortened. This is because, in the present embodiment, when the measurement result of the pressure of the acquired air increases from the previous time and is equal to or greater than the second pressure threshold value (Pth), the valve drive unit 260 performs control to open the valve 250, and therefore air leaks from the valve 250, and the pressure in the CPAP device 200 drops rapidly.

(actions of CPAP System)

Fig. 7 is a flow chart showing one example of the actions of the CPAP system of the embodiment of the present invention. Fig. 7 illustrates actions after CPAP system 100 is started. That is, the operation of the CPAP device 200 after the fan 210 is rotated is shown.

(step S1)

The pressure sensor 220 of the CPAP apparatus 200 measures the pressure of the air sent by the fan 210. The pressure sensor 220 outputs the measurement result of the air pressure to the motor drive unit 240 and the valve drive unit 260.

(step S2)

The motor drive unit 240 of the CPAP device 200 acquires the measurement result of the pressure of the air output from the pressure sensor 220, and determines the rotation speed set in the motor 230 based on the acquired measurement result of the pressure of the air. The motor driving unit 240 outputs information indicating the rotation speed to the motor 230 based on the determined rotation speed. The motor 230 rotates the fan 210 by acquiring information indicating the number of rotations output from the motor driving unit 240 and setting the acquired information indicating the number of rotations.

(step S3)

The valve driving unit 260 of the CPAP device 200 acquires the measurement result of the pressure of the air output from the pressure sensor 220, and determines whether or not the acquired measurement result of the pressure of the air is lower than the previous measurement result and equal to or lower than the first pressure threshold.

(step S4)

When the measurement result of the pressure of the air output from the pressure sensor 220 is lower than the previous measurement result and is equal to or lower than the first pressure threshold value, the valve driving unit 260 performs control to close the valve 250. By closing the valve 250, air does not flow out of the valve 250, and therefore, in the event of a pressure reduction due to the patient inhaling air, a pressure drop can be prevented.

(step S5)

The valve driving unit 260 determines whether or not the measurement result of the pressure of the air output from the pressure sensor 220 has increased from the previous time and is equal to or greater than the second pressure threshold value when the measurement result of the pressure of the air output from the pressure sensor 220 has not decreased from the previous time and is equal to or less than the first pressure threshold value, that is, when the measurement result of the pressure of the air has increased from the previous time and is greater than the first pressure threshold value, or when the measurement result of the pressure of the air has decreased from the previous time or is equal to or less than the first pressure threshold value.

(step S6)

When the measurement result of the pressure of the air output from the pressure sensor 220 is greater than the previous time and equal to or greater than the second pressure threshold, the valve driving unit 260 performs control to open the valve 250. By opening the valve 250, air flows out of the valve 250, and thus the pressure can be further reduced in the event of an increase in pressure due to the patient exhaling air.

In step S5, if the measurement result of the pressure of the air output by the pressure sensor 220 is less than the previous time and the second pressure threshold value is not reached, the process proceeds to step S1.

In addition, after the process of step S4 or step S6 ends, the flow proceeds to step S1.

In the flowchart shown in FIG. 5, steps S1-S2 and steps S3-S6 may also be reversed.

In the foregoing embodiment, the case where the valve 250 is provided in the CPAP apparatus 200 has been described, but the present invention is not limited to this example. For example, the tube 300 may be provided, and the mask 400 may be provided. By providing the valve 250 to the CPAP apparatus 200, since the valve 250 and the pressure sensor 220 are provided at close positions, the time from when the patient starts inhaling air until the valve 250 closes and the time from when the patient starts exhaling air until the valve 250 opens can be shortened as compared with the case where the valve 250 is provided at another position.

In the above-described embodiment, the case where the valve drive unit 260 performs the control of closing the valve 250 when the measurement result of the pressure of the air output from the pressure sensor 220 is smaller than the previous time and equal to or smaller than the first pressure threshold value has been described, but the present invention is not limited to this example. For example, the valve driving unit 260 may set the valve 250 to the closed state (in other words, the half-open state) compared to the previous time when the measurement result of the pressure of the air output from the pressure sensor 220 is smaller than the previous time and equal to or smaller than the first pressure threshold. With this configuration, the valve 250 can be closed in stages, and thus can be set to any pressure.

In the above-described embodiment, the case where the valve drive unit 260 performs the control of opening the valve 250 when the measurement result of the pressure of the air output from the pressure sensor 220 is greater than the previous time and is equal to or greater than the second pressure threshold value has been described, but the present invention is not limited to this example. For example, the valve driving unit 260 may set the valve 250 to the open state (in other words, the half-open state) compared to the previous time when the measurement result of the pressure of the air output from the pressure sensor 220 is greater than or equal to the second pressure threshold value than the previous time. With this configuration, the valve 250 can be opened in stages, and thus can be set to any pressure.

According to the CPAP system 100 of the embodiment, the CPAP system 100 includes the fan 210, the pressure sensor 220, the housing 270, the motor driver 240, the valve 250, and the valve driver 260. The fan 210 sucks air in and sends out. The pressure sensor 220 measures the pressure of the air sent by the fan 210. The housing 270 houses the fan 210 and the pressure sensor 220, and has an air inflow port AI through which air sent into the fan 210 flows in, and an air outflow port AO through which air sent out from the fan 210 flows out. The motor drive unit 240 controls the rotation speed of the fan 210 based on the pressure measured by the pressure sensor 220. The valve 250 regulates the pressure of the air supplied from the air outlet AO via the tube 300 to the mask 400 fitted to the patient PA. The valve driving unit 260 opens and closes the valve 250 based on the pressure measured by the pressure sensor 220. In the case where the pressure is reduced due to the patient inhaling air, the valve 250 is closed so that air does not flow out from the valve 250, and thus the pressure can be increased. On the other hand, when the pressure increases due to the exhalation of air by the patient, the valve 250 is opened, so that air can be caused to flow out from the valve 250, and the pressure can be further reduced. Therefore, the dyspnea condition of the patient using CPAP can be improved.

(first modification)

(overview of CPAP System)

Fig. 1 can be applied to an example of a CPAP system of the first modification. However, instead of the CPAP apparatus 200, a CPAP apparatus 200a is provided.

The CPAP system 100a includes a CPAP device 200a, a tube 300, and a mask 400.

In the CPAP system 100a of the first modification example, the CPAP device 200a controls the opening and closing of the valve 250 based on the PWM signal for driving the motor 230, as compared with the CPAP device 200 of the embodiment.

The CPAP device 200a included in the CPAP system 100a will be described in detail below.

Fig. 8 is a diagram showing an example of a CPAP device according to a first modification of the embodiment of the present invention. As shown in fig. 8, the CPAP device 200a includes a fan 210, a pressure sensor 220, a motor 230, a motor driver 240a, a valve 250, a valve driver 260a, and a housing 270.

The pressure sensor 220 is built in the housing 270, and periodically measures the pressure of the air sent by the fan 210. The pressure sensor 220 periodically outputs the measurement result of the air pressure to the motor drive unit 240 a.

The motor 230 is connected to the fan 210, and rotates the fan 210 based on information indicating the rotation speed output from the motor driving unit 240 a.

The motor drive unit 240a obtains the measurement result of the pressure of the air output from the pressure sensor 220. The motor drive unit 240a determines the rotation speed set in the motor 230 based on the obtained measurement result of the pressure of the air. The motor driving unit 240a outputs information indicating the rotation speed to the motor 230 and the valve driving unit 260a based on the determined rotation speed. One example of the information indicating the rotation speed output by the motor driving unit 240a is a PWM signal.

The motor drive unit 240a increases the duty ratio of the PWM signal when the measurement result of the air pressure decreases due to the patient inhaling the air, based on the acquired measurement result of the air pressure. With such a configuration, the rotation speed of the fan 210 can be increased, and therefore, air pressurized for a patient who breathes in air can be sent to the respiratory tract through the nose.

On the other hand, the motor drive unit 240 decreases the duty ratio when the measurement result of the air pressure increases due to the patient exhaling the air based on the acquired measurement result of the air pressure. With such a configuration, the rotation speed of the fan 210 can be reduced, and thus the pressure of the air supplied to the mask 400 can be reduced for the patient who exhales the air.

The valve driving unit 260a acquires information indicating the rotation speed output by the motor driving unit 240 a. The valve driving unit 260a opens and closes the valve 250 based on the acquired information indicating the rotation speed. Specifically, the valve driving unit 260a is configured by, for example, an F/V converter (frequency/voltage converter), and converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotation speed. When the dc voltage obtained by converting the pulse signal is lower than the previous voltage and is equal to or lower than the first voltage threshold, the valve driving unit 260a performs control to close the valve 250. Here, the case where the direct-current voltage is reduced from the previous time and is equal to or lower than the first voltage threshold includes a case where the pressure is reduced due to the patient inhaling air. In this way, when the pressure is reduced by the patient inhaling the air, the valve driving portion 260a closes the valve 250, so that the air does not flow out from the valve 250, and thus the pressure drop can be prevented.

On the other hand, the valve driving unit 260a converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotation speed. When the dc voltage obtained by converting the pulse signal is higher than the previous voltage and is equal to or higher than the second voltage threshold, the valve driving unit 260a performs control to open the valve 250. The second voltage threshold is higher than the first voltage threshold. Here, the case where the dc voltage is increased from the previous time and is equal to or higher than the second voltage threshold includes a case where the dc voltage is increased due to the patient exhaling air. In this way, when the voltage increases due to the patient exhaling air, the valve driving unit 260a opens the valve 250, and air flows out from the valve 250, so that the pressure can be reduced.

Fig. 6 can be applied to an example of a characteristic diagram showing the response time of the CPAP system 100a according to the first modification. That is, it is understood that the rotation speed increase response time T1 is the same degree, but the rotation speed decrease response time T2 is shortened. This is because, in the first modification, the valve driving unit 260 performs control to open the valve 250 when the dc voltage is higher than the previous voltage and equal to or higher than the second voltage threshold value based on the acquired information indicating the rotation speed, and the pressure is rapidly decreased.

(actions of CPAP System)

Fig. 9 is a flowchart showing an example of the operation of the CPAP system according to the first modification of the embodiment of the present invention. Fig. 9 illustrates the actions after CPAP system 100a is activated. That is, the operation of the CPAP device 200a after the fan 210 is rotated is shown.

(step S11)

The pressure sensor 220 of the CPAP apparatus 200a measures the pressure of the air sent by the fan 210. The pressure sensor 220 outputs the measurement result of the air pressure to the motor drive unit 240 a.

(step S12)

The motor drive unit 240a of the CPAP device 200a acquires the measurement result of the pressure of the air output from the pressure sensor 220, and determines the rotation speed set in the motor 230 based on the acquired measurement result of the pressure of the air. The motor driving unit 240a outputs information indicating the rotation speed to the motor 230 and the valve driving unit 260a based on the determined rotation speed. The motor 230 rotates the fan 210 by acquiring information indicating the number of rotations output from the motor driving unit 240a and setting the acquired information indicating the number of rotations.

(step S13)

The valve driving unit 260a of the CPAP device 200a acquires information indicating the rotational speed output by the motor driving unit 240a, and converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotational speed. The valve driving unit 260a determines whether or not the dc voltage obtained by converting the pulse signal is lower than the previous voltage and equal to or lower than the first voltage threshold.

(step S14)

The valve driving unit 260a performs control to close the valve 250 when the dc voltage is lower than the previous voltage and equal to or lower than the first voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 a. By closing the valve 250, air does not flow out of the valve 250, and therefore, in the event of a pressure reduction due to the patient inhaling air, a pressure drop can be prevented.

(step S15)

The valve driving unit 260a determines whether or not the dc voltage has increased from the previous time and is equal to or higher than the second voltage threshold, when the dc voltage has not decreased from the previous time and is equal to or lower than the first voltage threshold, that is, when the dc voltage has increased from the previous time and is higher than the first voltage threshold, and when the dc voltage has decreased from the previous time or is equal to or lower than the first voltage threshold, based on the information indicating the rotation speed output by the motor driving unit 240 a.

(step S16)

The valve driving unit 260a performs control to open the valve 250 when the dc voltage is higher than the previous voltage and equal to or higher than the second voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 a. By opening the valve 250, air flows out of the valve 250, and thus the pressure can be further reduced in the case where the pressure is reduced due to the exhalation of air by the patient.

In step S15, when the dc voltage is reduced from the previous one or is less than the first voltage threshold value based on the information indicating the rotation speed output by the motor driver 240a, the process proceeds to step S11.

In addition, after the process of step S14 or step S16 ends, the flow proceeds to step S11.

In the flowchart shown in FIG. 9, steps S11-S12 and steps S13-S16 may also be reversed.

In the first modification described above, the case where the valve 250 is provided in the CPAP device 200a is described, but the present invention is not limited to this example. For example, the tube 300 may be provided, and the mask 400 may be provided. By providing the valve 250 in the CPAP apparatus 200a, since the valve 250 and the pressure sensor 220 are provided at close positions, the time from when the patient starts inhaling air until the valve 250 closes and the time from when the patient starts exhaling air until the valve 250 opens can be shortened as compared with the case where the valve 250 is provided at another position.

In the first modification described above, the following is explained, but the present invention is not limited to this example: the CPAP device 200a performs control to close the valve 250 when the dc voltage obtained by converting the pulse signal is lower than the previous time and equal to or lower than the first voltage threshold value, and performs control to open the valve 250 when the dc voltage is higher than the previous time and equal to or higher than the second voltage threshold value, based on the acquired information indicating the rotational speed. For example, the CPAP device 200a may perform control to open the valve 250 when the rotation speed decreases from the previous rotation speed and is equal to or less than the first rotation speed threshold value, and perform control to close the valve 250 when the rotation speed increases from the previous rotation speed and is equal to or more than the second rotation speed threshold value, based on the acquired information indicating the rotation speed. The second rotational speed threshold is higher than the first rotational speed threshold. With such a configuration, the process of converting the rotational speed into the dc voltage can be omitted.

In the first modification described above, the following is explained, but the present invention is not limited to this example: the valve driving unit 260a performs control to close the valve 250 when the dc voltage is lower than the previous voltage and equal to or lower than the first voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 a. For example, the valve driving unit 260a may set the valve 250 to the closed state (in other words, the half-open state) compared to the previous time when the dc voltage is lower than the previous time and equal to or lower than the first voltage threshold value based on the information indicating the rotation speed output by the motor driving unit 240 a. With this configuration, the valve 250 can be closed in stages, and thus can be set to any pressure.

In the first modification described above, the following is explained, but the present invention is not limited to this example: the valve driving unit 260a performs control to open the valve 250 when the dc voltage is higher than the previous voltage and equal to or higher than the second voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 a. For example, the valve driving unit 260a may set the valve 250 to the open state (in other words, the half-open state) compared to the previous time when the dc voltage is higher than the previous time and is equal to or higher than the second voltage threshold. With this configuration, the valve 250 can be opened in stages, and thus can be set to any pressure.

According to the CPAP system 100a of the first modification, the CPAP system 100a includes the fan 210, the pressure sensor 220, the housing 270, the motor drive unit 240a, the valve 250, and the valve drive unit 260 a. The fan 210 sucks air in and sends out. The pressure sensor 220 measures the pressure of the air sent by the fan 210. The housing 270 houses the fan 210 and the pressure sensor 220, and has an air inflow port AI through which air sent into the fan 210 flows in, and an air outflow port AO through which air sent out from the fan 210 flows out. The motor drive unit 240a controls the rotation speed of the fan 210 based on the pressure measured by the pressure sensor 220. The valve 250 regulates the pressure of the air supplied from the air outlet AO via the tube 300 to the mask 400 fitted to the patient PA. The valve driving unit 260a opens and closes the valve 250 based on the pressure measured by the pressure sensor 220. The motor driving unit 240a controls the rotation speed of the fan 210 based on the PWM signal, and the valve driving unit 260a opens and closes the valve 250 based on the PWM signal. In the case where the pressure is reduced due to the patient inhaling air, the pressure can be increased by closing the valve 250 so that air does not flow out from the valve 250. In addition, when the pressure increases due to the exhalation of air by the patient, the valve 250 is opened, so that air can be caused to flow out from the valve 250, and the pressure can be further reduced. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260a closes the valve 250 when the duty ratio of the PWM signal is equal to or less than the first threshold value, and opens the valve 250 when the duty ratio of the PWM signal is equal to or more than the second threshold value. When the pressure is reduced by the patient inhaling air and the duty ratio of the PWM signal becomes equal to or less than the first threshold value, the valve 250 is closed so that air does not flow out from the valve 250, and the pressure can be increased. Further, when the pressure increases due to the exhalation of air by the patient and the duty ratio of the PWM signal becomes equal to or higher than the second threshold value, the valve 250 is opened to allow air to flow out from the valve 250, so that the pressure can be further reduced. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260a opens and closes the valve 250 based on the voltage signal obtained by converting the PWM signal into a voltage. In the case where the pressure is reduced due to the patient inhaling air, the pressure can be further increased by closing the valve 250 so that air does not flow out from the valve 250. In addition, when the pressure increases due to the exhalation of air by the patient, the valve 250 is opened, so that air can be caused to flow out from the valve 250, and the pressure can be further reduced. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260a closes the valve 250 when the voltage is equal to or lower than the first voltage threshold value, and opens the valve 250 when the voltage is equal to or higher than the second voltage threshold value, based on the voltage signal. When the pressure is reduced by the patient inhaling air and the voltage becomes equal to or lower than the first voltage threshold, the valve 250 is closed so that air does not flow out of the valve 250, and the pressure can be increased. Further, when the pressure increases due to the patient exhaling air and the voltage becomes equal to or higher than the second voltage threshold, the valve 250 is opened to allow air to flow out from the valve 250, so that the pressure can be further reduced. Therefore, the dyspnea condition of the patient using CPAP can be improved.

(second modification)

(overview of CPAP System)

Fig. 1 can be applied to an example of a CPAP system of the second modification. However, instead of the CPAP apparatus 200, a CPAP apparatus 200b is provided.

The CPAP system 100b includes a CPAP device 200b, a tube 300, and a mask 400.

In the CPAP system 100b of the second modification example, the CPAP device 200b includes a flow sensor instead of the pressure sensor, as compared with the CPAP device 200 of the embodiment.

The CPAP device 200b included in the CPAP system 100b will be described in detail below.

Fig. 10 is a diagram showing an example of a CPAP device according to a second modification of the embodiment of the present invention. As shown in fig. 10, the CPAP device 200b includes a fan 210, a flow sensor 220b, a motor 230, a motor driver 240b, a valve 250, a valve driver 260b, and a housing 270.

The flow rate sensor 220b is incorporated in the housing 270, and periodically measures the flow rate of the air sent by the fan 210. The flow rate sensor 220b periodically outputs the measurement result of the flow rate of the air to the motor drive unit 240b and the valve drive unit 260 b.

The motor 230 is connected to the fan 210, and rotates the fan 210 based on information indicating the rotation speed output from the motor driving unit 240 b.

The motor drive unit 240b obtains the measurement result of the flow rate of the air output from the flow rate sensor 220 b. The motor drive unit 240b determines the rotation speed set in the motor 230 based on the measurement result of the acquired air flow rate. The motor driving unit 240b outputs information indicating the rotation speed to the motor 230 based on the determined rotation speed.

Fig. 5 can be applied to one example of the information indicating the rotation speed. One example of the information indicating the rotation speed output by the motor driving unit 240b is a PWM signal.

The motor drive unit 240b increases the duty ratio, which is a ratio of the time during which the PWM signal is on to the period during which the PWM signal is repeatedly on and off, when the measurement result of the flow rate of air increases due to the patient inhaling air, based on the acquired measurement result of the flow rate of air. With such a configuration, the rotation speed of the fan 210 can be increased, and thus a high flow rate of air can be sent from the nose to the respiratory tract for a patient who breathes in air.

On the other hand, the motor drive unit 240 decreases the duty ratio when the measurement result of the flow rate of air decreases due to the patient exhaling the air based on the obtained measurement result of the flow rate of air. With such a configuration, the number of rotations of the fan 210 can be reduced, and thus the flow rate of air supplied to the mask 400 can be reduced for a patient who exhales air.

The valve 250 is built into the housing 270 and regulates the flow of air supplied from the air outlet AO to the mask 400 fitted to the patient PA via a tube 300 connected to the air outlet AO. One example of valve 250 is a solenoid valve, a linear valve, a wastegate valve. Specifically, the valve 250 opens and closes the valve 250 in accordance with the control performed by the valve driving unit 260b, thereby adjusting the flow rate of air supplied from the air outlet AO to the mask 400 attached to the patient PA via the tube 300.

The valve driving unit 260b obtains the measurement result of the flow rate of the air output from the flow rate sensor 220 b. The valve driving unit 260b opens and closes the valve 250 based on the obtained measurement result of the flow rate of the air. Specifically, when the acquired measurement result of the flow rate of the air increases more than the previous time and is equal to or more than the first flow rate threshold value, the valve driving unit 260b performs control to close the valve 250. Here, the case where the measurement result of the flow rate of the air is increased more than the previous time and is equal to or more than the first flow rate threshold value includes a case where the flow rate is increased due to the patient inhaling the air. In this way, when the flow rate increases due to the patient inhaling air, the valve driving portion 260b closes the valve 250, so that air does not flow out from the valve 250, and thus the flow rate can be prevented from decreasing.

On the other hand, when the acquired measurement result of the flow rate of the air is smaller than the previous measurement result and is equal to or smaller than the second flow rate threshold value, the valve driving unit 260 performs control to open the valve 250. The second flow threshold is less than the first flow threshold. Here, the case where the measurement result of the flow rate of air is lower than the previous time and is equal to or lower than the second flow rate threshold value includes a case where the flow rate is reduced due to the exhalation of air by the patient. In this way, when the flow rate decreases due to the patient exhaling air, the valve drive unit 260 opens the valve 250, so that air flows out from the valve 250, and the flow rate can be decreased.

(actions of CPAP System)

Fig. 11 is a flowchart showing an example of the operation of the CPAP system of the second modification. Fig. 11 illustrates the actions after CPAP system 100b is activated. That is, the operation of the CPAP device 200b after the fan 210 is rotated is shown.

(step S21)

The flow sensor 220b of the CPAP apparatus 200b measures the flow rate of air sent by the fan 210. The flow rate sensor 220b outputs the measurement result of the flow rate of the air to the motor driving unit 240b and the valve driving unit 260 b.

(step S22)

The motor drive unit 240b of the CPAP device 200b acquires the measurement result of the flow rate of the air output from the flow rate sensor 220b, and determines the rotation speed set in the motor 230 based on the acquired measurement result of the flow rate of the air. The motor driving unit 240b outputs information indicating the rotation speed to the motor 230 based on the determined rotation speed. The motor 230 rotates the fan 210 by acquiring information indicating the number of rotations output from the motor driving unit 240b and setting the acquired information indicating the number of rotations.

(step S23)

The valve driving unit 260b of the CPAP device 200b acquires the measurement result of the flow rate of the air output from the flow rate sensor 220b, and determines whether or not the acquired measurement result of the flow rate of the air is greater than the previous time and is equal to or greater than the first flow rate threshold value.

(step S24)

When the measurement result of the flow rate of the air output from the flow rate sensor 220b is greater than the previous time and is equal to or greater than the first flow rate threshold value, the valve driving unit 260b performs control to close the valve 250. By closing the valve 250, air does not flow out of the valve 250, and thus, in the case where the flow rate increases due to the patient inhaling the air, the flow rate can be prevented from decreasing.

(step S25)

The valve driving unit 260b determines whether or not the measurement result of the flow rate of air is smaller than the previous flow rate threshold and equal to or smaller than the second flow rate threshold when the measurement result of the flow rate of air output by the flow rate sensor 220b is not larger than the previous flow rate threshold and is larger than the first flow rate threshold, that is, when the measurement result of the flow rate of air is smaller than the previous flow rate threshold and is smaller than the first flow rate threshold, and when the measurement result of the flow rate of air is larger than the previous flow rate threshold or is larger than the first flow rate threshold.

(step S26)

When the measurement result of the flow rate of the air output from the flow rate sensor 220b is smaller than the previous measurement result and is equal to or smaller than the second flow rate threshold value, the valve driving unit 260 performs control to open the valve 250. By opening the valve 250, air flows out from the valve 250, and therefore, when the flow rate is reduced by the patient exhaling air, the flow rate can be further reduced.

In step S25, if the measurement result of the flow rate of air output by the flow rate sensor 220b is smaller than the previous time or larger than the second flow rate threshold value, the process proceeds to step S21.

In addition, after the process of step S24 or step S26 ends, the flow proceeds to step S21.

In the flowchart shown in FIG. 12, steps S21-S22 and steps S23-S26 may also be reversed.

In the second modification described above, the case where the valve 250 is provided in the CPAP device 200b is described, but the present invention is not limited to this example. For example, the tube 300 may be provided, and the mask 400 may be provided. By providing the valve 250 to the CPAP apparatus 200b, since the valve 250 and the flow sensor 220b are provided at close positions, the time from when the patient starts to inhale air to when the valve 250 is closed and the time from when the patient starts to exhale air to when the valve 250 is opened can be shortened as compared with the case where the valve 250 is provided at another position.

In the foregoing embodiment, the following is explained, but not limited to this example: when the measurement result of the flow rate of the air output from the flow rate sensor 220b is greater than the previous time and is equal to or greater than the first flow rate threshold value, the valve driving unit 260b performs control to close the valve 250. For example, the valve driving unit 260b may set the valve 250 to the closed state (in other words, the half-open state) compared to the previous time when the measurement result of the flow rate of the air output from the flow rate sensor 220b is greater than or equal to the first flow rate threshold value than the previous time. With this configuration, the valve 250 can be closed in stages, and thus can be set to an arbitrary flow rate.

In the foregoing embodiment, the following is explained, but not limited to this example: when the measurement result of the flow rate of the air output from the flow rate sensor 220b is smaller than the previous measurement result and is equal to or smaller than the second flow rate threshold value, the valve driving unit 260b performs control to open the valve 250. For example, the valve driving unit 260b may set the valve 250 to the open state (in other words, the half-open state) compared to the previous time when the measurement result of the flow rate of the air output from the flow rate sensor 220b is smaller than the previous time and is equal to or smaller than the second flow rate threshold value. With this configuration, the valve 250 can be opened in stages, and thus can be set to an arbitrary flow rate.

According to the CPAP system 100b of the second modification, the CPAP system 100b includes the fan 210, the flow sensor 220b, the housing 270, the motor drive unit 240b, the valve 250, and the valve drive unit 260 b. The fan 210 sucks air in and sends out. The flow rate sensor 220b measures the flow rate of the air sent by the fan 210. The housing 270 houses the fan 210 and the flow sensor 220b, and has an air inflow port AI through which air sent into the fan 210 flows in, and an air outflow port AO through which air sent out from the fan 210 flows out. The motor drive unit 240b controls the rotation speed of the fan 210 based on the flow rate measured by the flow rate sensor 220 b. The valve 250 regulates the flow of air supplied from the air outlet AO via the tube 300 to the mask 400 fitted to the patient PA. The valve driving unit 260b opens and closes the valve 250 based on the flow rate measured by the flow rate sensor 220 b. When the flow rate is reduced due to the patient inhaling air, the valve 250 is closed so that air does not flow out from the valve 250, and thus the flow rate can be increased. On the other hand, when the flow rate increases due to the patient exhaling air, the valve 250 is opened to allow air to flow out from the valve 250, and thus the flow rate can be further decreased. Therefore, the dyspnea condition of the patient using CPAP can be improved.

(third modification)

(overview of CPAP System)

Fig. 1 can be applied to an example of a CPAP system of the third modification. However, instead of the CPAP apparatus 200, a CPAP apparatus 200c is provided.

The CPAP system 100c includes a CPAP device 200c, a tube 300, and a mask 400.

In the CPAP system 100c of the third modification example, the CPAP device 200c controls the opening and closing of the valve 250 based on the PWM signal for driving the motor 230, as compared with the CPAP device 200b of the third modification example.

The CPAP device 200c included in the CPAP system 100c will be described in detail below.

Fig. 12 is a diagram showing an example of a CPAP device according to a third modification of the embodiment of the present invention. As shown in fig. 12, the CPAP device 200c includes a fan 210, a flow sensor 220c, a motor 230, a motor driver 240c, a valve 250, a valve driver 260c, and a housing 270.

The flow rate sensor 220c is built in the housing 270, and periodically measures the flow rate of the air sent by the fan 210. The flow rate sensor 220c periodically outputs the measurement result of the flow rate of the air to the motor drive unit 240 c.

The motor 230 is connected to the fan 210, and rotates the fan 210 based on information indicating the rotation speed output from the motor driving unit 240 c.

The motor drive unit 240c obtains the measurement result of the flow rate of the air output from the flow rate sensor 220 c. The motor drive unit 240c determines the rotation speed set in the motor 230 based on the measurement result of the acquired air flow rate. The motor driving unit 240c outputs information indicating the rotation speed to the motor 230 and the valve driving unit 260c based on the determined rotation speed. One example of the information indicating the rotation speed output by the motor driving unit 240c is a PWM signal.

The motor drive unit 240c increases the duty ratio of the PWM signal when the measurement result of the flow rate of air increases due to the patient inhaling air, based on the obtained measurement result of the flow rate of air. With such a configuration, the rotation speed of the fan 210 can be increased, and thus a high flow rate of air can be sent from the nose to the respiratory tract for a patient who breathes in air.

On the other hand, the motor drive unit 240c decreases the duty ratio when the measurement result of the flow rate of air decreases due to the patient exhaling the air based on the obtained measurement result of the flow rate of air. With such a configuration, the number of rotations of the fan 210 can be reduced, and thus the flow rate of air supplied to the mask 400 can be reduced for a patient who exhales air.

The valve driving unit 260c acquires information indicating the rotation speed output by the motor driving unit 240 c. The valve driving unit 260c opens and closes the valve 250 based on the acquired information indicating the rotation speed. Specifically, the valve driving unit 260c is configured by, for example, an F/V converter (frequency/voltage converter), and converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotation speed. When the dc voltage obtained by converting the pulse signal is higher than the previous voltage and is equal to or higher than the voltage threshold, the valve driving unit 260c performs control to close the valve 250. Here, the case where the dc voltage is increased more than the previous time and is equal to or higher than the voltage threshold includes a case where the flow rate is increased due to the patient inhaling air. In this way, when the flow rate increases due to the patient inhaling air, the valve driving portion 260c closes the valve 250, so that air does not flow out from the valve 250, and thus the flow rate can be prevented from decreasing.

On the other hand, the valve driving unit 260c converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotation speed. When the dc voltage obtained by converting the pulse signal is reduced from the previous voltage and is less than the voltage threshold, the valve driving unit 260c performs control to open the valve 250. Here, the case where the dc voltage is reduced compared to the previous time and the voltage threshold is not reached includes the case where the dc voltage is reduced due to the exhalation of air by the patient. In this way, when the voltage decreases due to the patient exhaling air, the valve driving unit 260c opens the valve 250, and thus air flows out from the valve 250, so that the flow rate can be decreased.

(actions of CPAP System)

Fig. 13 is a flowchart showing an example of the operation of the CPAP system according to the third modification of the embodiment of the present invention. Fig. 13 illustrates the action after CPAP system 100c is activated. That is, the operation of the CPAP device 200c after the fan 210 is rotated is shown.

(step S31)

The flow sensor 220c of the CPAP apparatus 200c measures the flow rate of air sent by the fan 210. The flow rate sensor 220c outputs the measurement result of the flow rate of the air to the motor driving unit 240 c.

(step S32)

The motor drive unit 240c of the CPAP device 200c acquires the measurement result of the flow rate of the air output from the flow rate sensor 220c, and determines the rotation speed set in the motor 230 based on the acquired measurement result of the flow rate of the air. The motor driving unit 240c outputs information indicating the rotation speed to the motor 230 and the valve driving unit 260c based on the determined rotation speed. The motor 230 acquires information indicating the number of rotations output from the motor driving unit 240c, and sets the acquired information indicating the number of rotations, thereby rotating the fan 210.

(step S33)

The valve driving unit 260c of the CPAP device 200c acquires information indicating the rotational speed output by the motor driving unit 240c, and converts the pulse signal into a dc voltage proportional to the frequency of the pulse based on the acquired information indicating the rotational speed. The valve driving unit 260c determines whether or not the dc voltage obtained by converting the pulse signal is higher than the previous voltage and is equal to or higher than a voltage threshold.

(step S34)

The valve driving unit 260c performs control to close the valve 250 when the dc voltage is higher than the previous voltage and is equal to or higher than the voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 c. By closing the valve 250, air does not flow out of the valve 250, and thus, in the case where the flow rate increases due to the patient inhaling the air, the flow rate can be prevented from decreasing.

(step S35)

The valve driving unit 260c determines whether or not the dc voltage has decreased from the previous time and is less than the voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240c, when the dc voltage has not increased from the previous time and is equal to or greater than the voltage threshold value, that is, when the dc voltage has decreased from the previous time and is less than the voltage threshold value, or when the dc voltage has decreased from the previous time and is equal to or greater than the voltage threshold value.

(step S36)

The valve driving unit 260c performs control to open the valve 250 when the dc voltage is lower than the previous voltage and less than the voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 c. By opening the valve 250, air flows out from the valve 250, and therefore, when the flow rate is reduced by the patient exhaling air, the flow rate can be further reduced.

In step S35, when the dc voltage is lower than the previous voltage or is less than the voltage threshold value based on the information indicating the rotation speed output by the motor driver 240c, the process proceeds to step S31.

In addition, after the process of step S34 or step S36 ends, the flow proceeds to step S31.

In the flowchart shown in FIG. 13, steps S31-S32 and steps S33-S36 may also be reversed.

In the third modification described above, the case where the valve 250 is provided in the CPAP device 200c is described, but the present invention is not limited to this example. For example, the tube 300 may be provided, and the mask 400 may be provided. By providing the valve 250 to the CPAP apparatus 200c, since the valve 250 and the flow sensor 220c are provided at close positions, the time from when the patient starts to inhale air to when the valve 250 is closed and the time from when the patient starts to exhale air to when the valve 250 is opened can be shortened as compared with the case where the valve 250 is provided at another position.

In the third modification described above, the following is explained, but the present invention is not limited to this example: the CPAP device 200c performs control to open the valve 250 when the dc voltage obtained by converting the pulse signal is lower than the previous time and is less than the voltage threshold value, and performs control to close the valve 250 when the dc voltage is higher than the previous time and is equal to or higher than the voltage threshold value, based on the acquired information indicating the rotational speed. For example, the CPAP device 200c may perform control to open the valve 250 when the rotation speed decreases from the previous rotation speed and becomes less than the rotation speed threshold value, and perform control to close the valve 250 when the rotation speed increases from the previous rotation speed and becomes equal to or greater than the rotation speed threshold value, based on the acquired information indicating the rotation speed. With such a configuration, the process of converting the rotational speed into the dc voltage can be omitted.

In the third modification described above, the following is explained, but the present invention is not limited to this example: the valve driving unit 260c performs control to close the valve 250 when the dc voltage is higher than the previous voltage and is equal to or higher than the voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 c. For example, the valve driving unit 260c may set the valve 250 to the closed state (in other words, the half-open state) compared to the previous time when the dc voltage is higher than the previous time and is equal to or higher than the voltage threshold value based on the information indicating the rotation speed output by the motor driving unit 240 c. With this configuration, the valve 250 can be closed in stages, and thus can be set to an arbitrary flow rate.

In the third modification described above, the following is explained, but the present invention is not limited to this example: the valve driving unit 260c performs control to open the valve 250 when the dc voltage is lower than the previous voltage and less than the voltage threshold value, based on the information indicating the rotation speed output by the motor driving unit 240 c. For example, the valve driving unit 260c may set the valve 250 to the open state (in other words, the half-open state) compared to the previous time when the dc voltage is reduced compared to the previous time and the voltage threshold value is not reached. With this configuration, the valve 250 can be opened in stages, and thus can be set to an arbitrary flow rate.

According to the CPAP system 100c of the third modification, the CPAP system 100c includes the fan 210, the flow sensor 220c, the housing 270, the motor drive unit 240c, the valve 250, and the valve drive unit 260 c. The fan 210 sucks air in and sends out. The flow rate sensor 220c measures the flow rate of the air sent by the fan 210. The housing 270 houses the fan 210 and the flow sensor 220c, and has an air inflow port AI through which air sent into the fan 210 flows in, and an air outflow port AO through which air sent out from the fan 210 flows out. The motor driving unit 240c controls the rotation speed of the fan 210 based on the flow rate measured by the flow rate sensor 220 c. The valve 250 regulates the flow of air supplied from the air outlet AO via the tube 300 to the mask 400 fitted to the patient PA. The valve driving unit 260c opens and closes the valve 250 based on the flow rate measured by the flow rate sensor 220 c. The motor driving unit 240c controls the rotation speed of the fan 210 based on the PWM signal, and the valve driving unit 260c opens and closes the valve 250 based on the PWM signal. In the case where the flow rate increases due to the patient inhaling air, the flow rate can be increased by closing the valve 250 so that air does not flow out from the valve 250. In addition, when the flow rate decreases due to the patient exhaling air, the valve 250 is opened to allow air to flow out from the valve 250, and thus the flow rate can be further decreased. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260c closes the valve 250 when the duty ratio of the PWM signal is equal to or greater than the threshold value, and opens the valve 250 when the duty ratio of the PWM signal is less than the threshold value. When the flow rate increases due to the patient inhaling air and the duty ratio of the PWM signal becomes equal to or higher than the threshold value, the valve 250 is closed so that air does not flow out from the valve 250, and thus the flow rate can be increased. Further, when the flow rate decreases due to the exhalation of air by the patient and the duty ratio of the PWM signal becomes less than the threshold value, the valve 250 is opened to allow air to flow out from the valve 250, so that the flow rate can be further decreased. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260c opens and closes the valve 250 based on the voltage signal obtained by converting the PWM signal into a voltage. In the case where the flow rate increases due to the patient inhaling air, the valve 250 is closed so that air does not flow out from the valve 250, and thus the flow rate can be further increased. In addition, when the flow rate decreases due to the patient exhaling air, the valve 250 is opened to allow air to flow out from the valve 250, and thus the flow rate can be further decreased. Therefore, the dyspnea condition of the patient using CPAP can be improved.

The valve driving unit 260c closes the valve 250 when the voltage is equal to or higher than the voltage threshold value, and opens the valve 250 when the voltage is lower than the voltage threshold value, based on the voltage signal. When the patient breathes in air and the flow rate increases, and the voltage becomes equal to or higher than the voltage threshold, the valve 250 is closed, so that air does not flow out from the valve 250, and the flow rate can be increased. Further, when the pressure becomes lower than the voltage threshold value due to a decrease in the flow rate caused by the patient's exhalation of air, the valve 250 is opened to allow air to flow out of the valve 250, thereby further reducing the flow rate. Therefore, the dyspnea condition of the patient using CPAP can be improved.

While the embodiments of the present invention have been described above, these embodiments are provided as examples and are not intended to limit the scope of the present invention. The embodiments may be implemented in various other ways, and various omissions, substitutions, and changes may be made without departing from the spirit of the invention. Examples of the embodiment or its modifications include an embodiment that can be easily conceived by those skilled in the art, a substantially similar embodiment, and an embodiment of an equivalent range.

Description of the symbols

100. 100a, 100b, 100c … CPAP system, 200a, 200b, 200c … CPAP device, 210 … … fan, 220 … … pressure sensor, 220b, 220c … … flow sensor, 230 … … motor, 240a, 240b, 240c … … motor drive, 250 … … valve, 260a, 260b, 260c … … valve drive, 270 … … housing, 300 … … tubing, 400 … … mask.

Claims

1. A CPAP system is provided with:

a fan that sucks in and sends out air;

a sensor for measuring the pressure or flow rate of the air sent by the fan;

a housing in which the fan and the sensor are placed, the housing having an air inlet through which air sent into the fan flows in and an air outlet through which air sent out from the fan flows out;

a motor drive unit that controls the rotation speed of the fan based on the pressure or the flow rate measured by the sensor;

a valve that adjusts the pressure or flow rate of air supplied from the air outlet port to a mask attached to a patient via a tube; and

and a valve driving unit that opens and closes the valve based on the pressure or the flow rate measured by the sensor.

2. A CPAP system according to claim 1, wherein the motor drive controls the speed of the fan according to a PWM signal,

the valve driving unit opens and closes the valve based on the PWM signal.

3. A CPAP system according to claim 2, wherein the valve driving unit closes the valve when the duty ratio of the PWM signal is equal to or greater than a threshold value, and opens the valve when the duty ratio of the PWM signal is less than the threshold value.

4. A CPAP system according to claim 2 wherein the valve drive section opens and closes the valve based on a voltage signal that converts the PWM signal into a voltage.

5. A CPAP system as claimed in claim 4, wherein the valve drive section closes the valve when a voltage is below a first voltage threshold value based on the voltage signal, and opens the valve when the voltage is above a second voltage threshold value that exceeds the first voltage threshold value.

6. A CPAP device is provided with:

a fan that sucks in and sends out air;

a sensor for measuring the pressure or flow rate of the air sent by the fan;