JP5320604B2 - Gas supply unit and gas mixing device - Google Patents

Description

  The present invention relates to a gas supply unit and a gas mixing device used for a breathing assistance device and the like.

  In the medical field, a respiratory assistance device such as a ventilator is used. This breathing assistance device has a controlled ventilation system for patients without spontaneous breathing (general anesthesia, cardiopulmonary resuscitation, and severe patients), and positive pressure (positive pressure) in the respiratory tract according to the patient's spontaneous breathing Assisted Ventilation method to create Assistance, Partial Assist / Control method combining auxiliary ventilation and controlled ventilation, oscillate the gas supplied by the airway at a frequency of 5-40 Hz, 1-2 ml / kg Various systems such as a high frequency oscillation system that realizes a very low tidal volume are adopted.

  In any type of respiratory assistance device, oxygen is supplied to the airway using an oxygen cylinder or the like. Some types of respiratory assistance devices include a mixing unit that mixes oxygen in an oxygen cylinder with air in the atmosphere (see, for example, Patent Document 1). This mixing unit changes the mixing ratio of oxygen and air by adjusting the flow rate of oxygen released from the oxygen cylinder.

JP 2004-298554 A

  However, in the above respiratory assistance device, when adjusting the flow rate of oxygen, the pressure in the airway also fluctuates accordingly, so it is difficult to set the airway to a desired pressure. That is, when the flow rate of oxygen is increased, the pressure in the airway is increased accordingly, which increases the burden on the patient. Such a problem occurs not only when oxygen and air are mixed, but also when other gases are mixed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas supply unit and a gas mixing device capable of simultaneously setting the air passage to a desired pressure while changing to a desired flow rate.

  The above-mentioned object is achieved by the following means based on the earnest research of the present inventors.

That is, this means for achieving the above object is a gas supply unit that constitutes a part of a medical respiratory assistance device, and generates a mixed gas by mixing a plurality of gases including the first gas. A flow rate adjusting valve for adjusting a flow rate of the first gas discharged from a supply source of the first gas in a gas supply unit for supplying the first gas to a gas mixing unit; A gas chamber disposed in the middle of the path from the gas mixing unit to the gas mixing unit or at a position branched from the path, the first gas being introduced, and an air opening opening toward the atmosphere; A flow rate sensor that detects a flow rate at the atmosphere port and outputs the detected flow rate as a signal, and a control unit that receives the signal output from the flow rate sensor and controls the flow rate adjustment valve based on the signal , Characterized in that it comprises the a gas supply unit.

Alternatively, this means for achieving the above object is a gas mixing device that forms part of a medical respiratory assistance device, and mixes a plurality of gases including a first gas to generate a mixed gas. A gas supply unit that supplies the first gas to the gas mixing unit, and the gas supply unit is configured to supply the first gas discharged from the first gas supply source. A flow rate adjusting valve that adjusts the flow rate, and the first gas is introduced in the middle of the path from the flow rate adjusting valve to the gas mixing unit or at a position branched from the path, and toward the atmosphere. A gas chamber having an open air opening; a flow rate sensor for detecting a flow rate at the air opening; outputting the detected flow rate as a signal; and receiving the signal output from the flow rate sensor; Characterized in that it comprises a control unit for controlling said flow control valve on the basis of the item, a gas mixing device.

  In the above invention, the gas mixing units that achieve the above object are arranged in parallel with each other, and each of the plurality of merging valves that receive the supply of the plurality of gases and allow the gases to pass therethrough, and A plurality of micropumps arranged one by one downstream to send out the gas that has passed through the merging valve; and a merging unit that joins the gases sent from each of the plurality of micropumps downstream of the plurality of micropumps; Are preferably provided.

  In the above invention, it is preferable that each of the plurality of merging valves that achieve the above object adjusts a ratio of the flow rates of the plurality of gases.

  Or in the said invention, it is preferable that each of the some confluence | merging valve which achieves the said objective switches the kind of gas to pass.

  According to the present invention, the first gas can be changed to a desired flow rate, and at the same time, an excellent effect that the inside of the airway can be set to a desired pressure, for example, a pressure of about atmospheric pressure can be achieved.

It is the schematic which shows the structure of the gas mixing apparatus which concerns on this invention. (A) It is the schematic which shows the structure of a gas mixing unit, (B) And (C) is the schematic which shows the structure of a confluence | merging valve. (A) is sectional drawing which shows the structural example of a micropump, (B) is a graph which shows the pressure-flow rate line of the micropump. It is a block diagram which shows the hardware constitutions of the control apparatus used with the same gas mixing apparatus. It is a block diagram which shows the function structure of the control apparatus used with the same gas mixing apparatus.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 illustrates the configuration of a gas mixing apparatus 10 according to the present invention. The gas mixing device 10 is a device that mixes a first gas and a second gas, and constitutes a part of a medical respiratory assistance device (not shown). In the present embodiment, a gas mixing device 10 that mixes oxygen serving as a first gas and air serving as a second gas will be described as an example.

  The gas mixing apparatus 10 is integrated with an oxygen supply unit 11 that supplies oxygen, an air supply unit 12 that supplies air, a gas mixing unit 13 that mixes oxygen and air to generate a mixed gas, and the entire apparatus. And a control unit 14 for controlling.

  However, the gas mixing apparatus 10 may include a plurality of control units that individually control the oxygen supply unit 11, the air supply unit 12, and the gas mixing unit 13 in place of the control unit 14. In this case, the plurality of control units cooperate with each other to integrally control the entire apparatus.

  The oxygen supply unit 11 is used together with the oxygen cylinder 15 and supplies oxygen that is compressed and confined in the oxygen cylinder 15 to the gas mixing unit 13. Specifically, the oxygen supply unit 11 is arranged in the middle of the flow rate adjusting valve 16 that adjusts the flow rate of oxygen released from the oxygen cylinder 15 and the flow from the flow rate adjusting valve 16 to the gas mixing unit 13, and oxygen is supplied. A gas chamber 17 having an atmosphere port 17a introduced and opened to the atmosphere, and a flow rate at the atmosphere port 17a, that is, a flow rate released from the gas chamber 17 to the atmosphere is detected, and the detected flow rate is detected. Is provided as a sensing signal.

  The flow rate adjustment valve 16 is controlled based on a sensing signal of the flow rate sensor 18 so that the inside of the gas chamber 17 has a pressure of about atmospheric pressure. The type of the flow rate adjusting valve 16 is not particularly limited, and an electric valve, an electromagnetic valve having a high response speed, or the like can be adopted.

  The gas chamber 17 is a space having a predetermined spread, and prevents oxygen from suddenly changing in the path from the flow regulating valve 16 to the gas mixing unit 13 when oxygen is released from the oxygen cylinder 15. Functions as a buffer space. In the present embodiment, the gas chamber 17 is disposed in the middle of the path from the flow rate adjustment valve 16 to the gas mixing unit 13, but may be disposed at a location branched from the path.

  The pressure in the gas chamber 17 is increased by introducing oxygen from the oxygen cylinder 15. On the other hand, the pressure in the gas chamber 17 is reduced by releasing oxygen in the gas chamber 17 from the atmosphere port 17 a to the atmosphere or releasing it to the gas mixing unit 13. That is, the pressure in the gas chamber 17 includes the flow rate of oxygen introduced from the oxygen cylinder 15, the flow rate of oxygen released from the atmosphere port 17 a to the atmosphere, and the flow rate of oxygen released to the gas mixing unit 13. Increase or decrease by percentage.

  In the present embodiment, the flow rate adjustment valve 16 is controlled to adjust the flow rate of oxygen introduced from the oxygen cylinder 15 and keep the pressure in the gas chamber 17 constant at about atmospheric pressure. Note that the flow rate of oxygen released from the atmosphere port 17a to the atmosphere is affected by the pressure in the gas chamber 17, and increases as the pressure in the gas chamber 17 increases. That is, in this embodiment, the flow rate of oxygen released from the atmosphere port 17a to the atmosphere is kept constant so that the pressure in the gas chamber 17 becomes constant at about atmospheric pressure.

  The flow rate of oxygen introduced from the oxygen cylinder 15 is adjusted by the flow rate adjustment valve 16. The flow rate of oxygen released from the atmosphere port 17a to the atmosphere is affected by the pressure in the gas chamber 17 and cannot be directly adjusted, but decreases when the pressure in the gas chamber 17 decreases. The flow rate of oxygen released to the gas mixing unit 13 is affected by the amount of oxygen used when the mixed gas is generated in the gas mixing unit 13 and cannot be directly adjusted. By controlling the amount of oxygen used when generating the mixed gas, the flow rate of oxygen released to the gas mixing unit 13 can be indirectly adjusted.

  The type of the flow sensor 18 is not particularly limited, and various types such as an electric type (electromagnetic type), a mechanical type (impeller type, float type, Kalman type, Coriolis type), ultrasonic type, thermal type, etc. The type can be adopted.

  The air supply unit 12 supplies air in the atmosphere to the gas mixing unit 13. Specifically, the air supply unit 12 includes a pump 19 that sends out air in the atmosphere, and a check valve 20 disposed in the middle of the path from the pump 19 to the gas mixing unit 13.

  The type of the pump 19 is not particularly limited, and a blower that sends a gas by rotating a fan, a cylinder pump that sends a gas by reciprocating a piston, and the like can be adopted. The check valve 20 prevents a back flow from the gas mixing unit 13 to the pump 19.

  In the present embodiment, the size of the atmosphere port 17a is constant, but a throttle valve (not shown) that makes the size of the atmosphere port 17a wider or narrower may be provided. The throttle valve is controlled together with the flow rate adjusting valve 16 based on a sensing signal of the flow rate sensor 18 and the like. Thereby, for example, the flow rate of oxygen released to the atmosphere increases by widening the atmosphere port 17a, so that even if the flow rate of oxygen released from the oxygen cylinder 15 increases, An increase in pressure is prevented. Moreover, since the flow rate of oxygen released into the atmosphere is reduced by narrowing the atmosphere port 17a, even if the flow rate of oxygen released from the oxygen cylinder 15 is reduced, it is released into the gas mixing unit 13. It is prevented that the flow rate of oxygen decreases.

  As shown in FIG. 2A, the gas mixing unit 13 includes an oxygen path branching portion 21 that branches the path from the oxygen supply unit 11 into a plurality (in this embodiment, five), and an air supply unit 12. An air path branching section 22 that branches into a plurality of paths (five in this embodiment), and downstream of the oxygen path branching section 21 and the air path branching section 22, these mixed gases are supplied with oxygen and air. A plurality (five in the present embodiment) of merging valves 23 and a plurality of merging valves 23 arranged one by one downstream of each of the plurality of merging valves 23 and sending out the mixed gas that has passed through the merging valve 23 (this embodiment). 5) micropumps 24, and a confluence section 25 that joins the mixed gas fed from each of the plurality of micropumps 24 downstream of the plurality of micropumps 24, It is provided.

  The type of the merging valve 23 is not particularly limited, but a rotary valve can be adopted as a valve for adjusting the ratio of the flow rate of oxygen and air. Specifically, as shown in FIGS. 2B and 2C, the merging valve 23 includes a rotating body 23a. The merging valve 23 changes the oxygen path width Wo and the air path width Wa by rotating the rotating body 23a.

  Since the plurality of micropumps 24 are arranged in parallel to each other, the total flow rate of the mixed gas delivered from the plurality of micropumps 24 is proportional to the number of micropumps 24 to be driven.

  Each of the plurality of micropumps 24 employs a micropump 100 shown in FIG. This micropump 100 is proposed in Patent Document WO2008 / 069266, and includes a primary blower chamber 101 and a secondary blower chamber 102 formed outside the primary blower chamber 101.

  The primary blower chamber 101 includes a piezoelectric element 103 serving as a vibration source, a diaphragm 104 to which the piezoelectric element 103 is fixed, and a vibration frame 105 that forms a space together with the diaphragm 104. The vibration frame 105 has an opening 106 that moves fluid inside and outside the primary blower chamber 101. The secondary blower chamber 102 has a suction port 107 on the diaphragm 104 side and a discharge port 108 so as to face the opening 106.

  In the micropump 100 described above, when the diaphragm 104 resonates by the piezoelectric element 103, the fluid moves between the primary blower chamber 101 and the secondary blower chamber 102, and the vibration frame 105 resonates due to the fluid resistance caused by the fluid. Due to the resonance between the diaphragm 104 and the vibration frame 105, the fluid is sucked from the suction port 107 and discharged from the discharge port 108.

  The micropump 100 is suitable for blower applications that transport gas, and can be transported without using a check valve. The micropump 100 has a box shape with an outer diameter of about 20 mm × 20 mm × 2 mm and is extremely small. However, when the input sine wave is set to 26 kHz at 15 Vpp (Volt peak to peak), the maximum is about 1 L / min (static pressure). Air at 0 Pa) and a maximum static pressure of about 2 kPa (flow rate 0 L / min) can be obtained.

  On the other hand, since the micropump 100 conveys the fluid by the vibration of the diaphragm 104 by the piezoelectric element 103, the volume of the fluid that can be conveyed is naturally limited, and this static pressure / flow rate characteristic is also shown in FIG. A straight line. That is, for example, when a static pressure of about 1 kPa is obtained, the flow rate is 0.5 L / min.

  Note that, when the Vpp of the input sine wave is changed to 10 or 20, the amplitude of the piezoelectric element 103 changes, so that the flow rate and pressure can be changed. That is, when Vpp of the input sine wave is changed smoothly, the flow rate and pressure can be changed smoothly. Alternatively, when the frequency of the input sine wave is changed, the flow rate and pressure can be changed. That is, when the frequency of the input sine wave is changed smoothly, the flow rate and pressure can be changed smoothly. However, the flow rate and pressure have upper limits depending on the ability of the piezoelectric element 103, the strength of the member, and the durability. Usually used at rated Vpp and frequency.

  Although a monomorph (unimorph) structure in which one piezoelectric element 103 is attached to the diaphragm 104 is introduced here, it is of course possible to adopt a bimorph structure in which two piezoelectric elements are attached to increase the vibration amount. . There are various other structures of the micropump 100 such as a structure suitable for liquid transport. Therefore, in the present invention, an optimum structure may be adopted according to the purpose. That is, the micropump 100 described here can convey gas without using a check valve, but instead of the micropump 100, a micropump having check valves at the suction port and the discharge port may be applied. good.

  As shown in FIG. 4, the control unit 14 includes, as a hardware configuration, a CPU 28, a first storage medium 29, a second storage medium 30, a third storage medium 31, an input device 32, and a display device 33. The input / output interface 34 and the bus 35 are provided.

  The CPU 28 is a so-called central processing unit, and implements various functions of the control unit 14 by executing various programs. The first storage medium 29 is a so-called RAM (Random Access Memory) and is used as a work area for the CPU 28. The second storage medium 30 is a so-called ROM (Read Only Memory), and stores a basic OS executed by the CPU 28. The third storage medium 31 includes a hard disk device with a built-in magnetic disk, a disk device that accommodates a CD, DVD, or BD, a non-volatile semiconductor flash memory device, and the like. Sensing data based on the sensing signal of the sensor 18 is stored.

  The input device 32 is an input key, a keyboard, or a mouse, and inputs various information. The display device 33 is a display and displays various operation states. The input / output interface 34 inputs / outputs a sensing signal of the flow rate sensor 18, a power source (sine wave waveform) for operating the micropump 24, and a control signal. Further, the input / output interface 34 acquires data such as a program from an external personal computer and outputs a sensing signal to the personal computer. The bus 35 is a wiring that performs communication by integrally connecting the CPU 28, the first storage medium 29, the second storage medium 30, the third storage medium 31, the input device 32, the display device 33, the input / output interface 34, and the like. .

  FIG. 5 shows a functional configuration obtained by the CPU 28 executing the control program stored in the control unit 14. The control unit 14 includes a sensing unit 38, a pump control unit 39, and a valve control unit 40 as functional configurations. The sensing unit 38 always acquires the sensing signal of the flow sensor 18 and transmits it to the valve control unit 40. The pump control unit 39 controls the Vpp and frequency of the input sine wave to the micropump 24 so as to approach the desired flow rate value and pressure value as targets. Further, the pump control unit 39 controls the pump 19 so as to approach a target desired flow rate value. The valve control unit 40 refers to the sensing signal of the sensing unit 38 and controls the control signal to the flow rate adjusting valve 16 so as to approach the desired flow rate value as a target. Furthermore, this valve control part 40 controls the confluence | merging valve 23 so that the ratio of oxygen and air may approach the target desired value.

  Next, a control example of the oxygen supply unit 11 will be described.

  The control unit 14 stores in advance the flow rate at the atmosphere port 17a when the pressure in the gas chamber 17 is about atmospheric pressure. The control unit 14 uses this data as a reference, based on the sensing signal of the flow sensor 18, whether or not the flow rate at the atmosphere port 17a is higher than when the pressure in the gas chamber 17 is about atmospheric pressure, that is, the reference Determine whether there are more. If it is determined that there is more than the reference, the control unit 14 controls the flow rate adjustment valve 16 to decrease the flow rate of oxygen released from the oxygen cylinder 15. By always performing this control, the atmospheric pressure in the gas chamber 17 can be maintained at a pressure of about atmospheric pressure.

  Next, a control example of the gas mixing unit 13 will be described.

  As described above, in order to keep the pressure in the gas chamber 17 constant at about atmospheric pressure, the control unit 14 controls the flow rate adjustment valve 16 to increase or decrease the flow rate of oxygen released from the oxygen cylinder 15. The ratio of the flow rate of oxygen and air is adjusted by controlling the merging valve 23 corresponding to the control of the flow rate adjusting valve 16. Specifically, when the flow rate of oxygen released from the oxygen cylinder 15 is increased, the oxygen path width Wo is made smaller than the air path width Wa, as shown in FIG. On the other hand, when the flow rate of oxygen released from the oxygen cylinder 15 is decreased, the oxygen path width Wo is made larger than the air path width Wa, as shown in FIG.

  When the flow rate of the mixed gas generated by the gas mixing unit 13 is increased or decreased, the control unit 14 controls to change the number of micro pumps 24 to be driven.

  As described above, according to the gas mixing device 10, the inside of the airway can be set to a pressure of about atmospheric pressure while changing the desired flow rate of oxygen.

  In addition, the gas supply unit and the gas mixing apparatus of the present invention are not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention. In addition, the configuration requirements of the above-described embodiment may be applied to other embodiments to the extent possible.

  That is, in the said embodiment, although the gas mixing apparatus 10 is an apparatus which mixes two types of gas, you may make it mix three or more types of gas.

  Or in the said embodiment, each of the confluence | merging valve 23 is a valve which adjusts the ratio of the flow volume of oxygen and air, However, The valve which switches the kind of gas to pass, ie, whether oxygen is allowed to pass through or air is allowed to pass through The valve which switches may be sufficient. In this case, the ratio of the flow rate of oxygen and air as a total is adjusted by changing the number of valves through which oxygen passes and the number of valves through which air passes.

  Or although the said embodiment demonstrated to the example the case where the inside of an airway can be set to the pressure of about atmospheric pressure, it is not limited to this, You may enable it to set the inside of an airway to a desired pressure. In this case, the control unit 14 may store in advance the flow rate at the atmosphere port 17a when the atmospheric pressure in the gas chamber 17 becomes a desired pressure. And the control unit 14 should just be made to control on the basis of the data.

  Alternatively, in the above embodiment, the gas mixing unit 13 includes a plurality of micropumps 24, but the plurality of micropumps 24 may not be included. In this case, the mixed gas is sent out by the flow of oxygen from the oxygen supply unit 11 and the flow of air from the air supply unit 12.

  Alternatively, in the above-described embodiment, the oxygen cylinder 15 is used as the first gas supply source. However, the supply source only needs to be able to send out the first gas, and may use a pump or the like.

10 Gas Mixing Device 11 Oxygen Supply Unit (Gas Supply Unit)
13 Gas mixing unit 14 Control unit (control unit)
15 Oxygen cylinder (source)
16 Flow Control Valve 17 Gas Chamber 17a Air Port 18 Flow Sensor 23 Junction Valve 24,100 Micropump 25 Junction Port

Claims (5)

A gas supply unit that constitutes a part of a medical respiratory assistance device, and that mixes a plurality of gases including the first gas to generate a mixed gas, the first gas In the gas supply unit for supplying
A flow rate adjusting valve for adjusting a flow rate of the first gas discharged from the source of the first gas;
The first gas is introduced in the middle of the path from the flow rate adjusting valve to the gas mixing unit, or at a position branched from the path, and has an atmosphere port that opens toward the atmosphere. A gas chamber;
A flow rate sensor that detects the flow rate at the atmosphere port and outputs the detected flow rate as a signal;
A controller that receives the signal output from the flow sensor and controls the flow control valve based on the signal;
Gas supply unit. A gas mixing device that forms part of a medical respiratory assistance device,
A gas mixing unit that generates a mixed gas by mixing a plurality of gases including the first gas;
A gas supply unit for supplying the first gas to the gas mixing unit;
The gas supply unit includes:
A flow rate adjusting valve for adjusting a flow rate of the first gas discharged from the source of the first gas;
The first gas is introduced in the middle of the path from the flow rate adjusting valve to the gas mixing unit, or at a position branched from the path, and has an atmosphere port that opens toward the atmosphere. A gas chamber;
A flow rate sensor that detects the flow rate at the atmosphere port and outputs the detected flow rate as a signal;
A controller that receives the signal output from the flow sensor and controls the flow control valve based on the signal;
Gas mixing device. The gas mixing unit includes:
A plurality of merging valves that are arranged in parallel with each other and each receive supply of the plurality of gases and pass the gases;
A plurality of micropumps arranged one by one downstream of each of the plurality of merging valves, and sending out the gas that has passed through the merging valves;
A merging portion for merging the gas sent from each of the plurality of micropumps downstream of the plurality of micropumps,
The gas mixing device according to claim 2. Each of the plurality of merging valves adjusts a ratio of the flow rates of the plurality of gases,
The gas mixing device according to claim 3. Each of the plurality of merging valves is characterized by switching the type of gas to be passed.
The gas mixing device according to claim 3.

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