JP5937476B2 - Oxygen supply equipment - Google Patents

Description

  The present invention relates to an oxygen supply device such as a pressure fluctuation adsorption oxygen concentrator, and more particularly to a breath-synchronized oxygen supply device that supplies oxygen only when a user inhales.

  One of the most effective treatments for respiratory diseases such as emphysema and chronic bronchitis is oxygen inhalation therapy. Recently, pressure fluctuation adsorption that separates oxygen in the air and supplies it as product gas for this therapy. A type (PSA) oxygen concentrator has been put into practical use and is used as a medical oxygen concentrator for the treatment of patients with chronic respiratory diseases. Recently, a portable oxygen concentrator has been developed to expand the application in place of carrying a portable oxygen cylinder when going out. Since the portable oxygen concentrator is driven by a battery, the device is equipped with a demand regulator function with a breath sensor and automatic open / close valve in order to prevent battery consumption and enable long-term operation. Instead of supplying it as a flow, oxygen is supplied only when the patient inhales, and oxygen supply is stopped during exhalation, thereby reducing the amount of oxygen produced and reducing power consumption.

JP-A 64-21330 JP-A-5-92038 JP 2004-242906 A

  Usually, such a demand regulator is equipped with an automatic opening / closing valve and breathing phase detection means provided in the middle of the oxygen supply flow path, and opens the automatic opening / closing valve only during the inspiratory time of the user and closes it during the expiration time. Can be saved to about 1/3. Such saving is particularly effective when the patient goes out with an oxygen cylinder or the like, and the travel time can be extended three times.

  The oxygen supply amount is prescribed by the doctor according to the severity of the patient, and the demand regulator must accurately detect the inspiratory time of the user and supply the necessary amount of oxygen at that time. Respiratory phase detection means for this purpose include pressure sensors that detect pressure changes associated with the user's breathing, and thermocouples that are placed near the nostril to detect the respiratory phase based on temperature changes. Many diaphragm type pressure sensors are used to detect fluctuations (Patent Documents 1 and 2).

  Conventionally, only oxygen intake is detected using a pressure sensor and oxygen is supplied. However, in order to supply oxygen more accurately, it is necessary to accurately detect the intake time. Therefore, it is necessary to detect not only the inspiration start time but also the expiration start time. On the other hand, for oxygen supply, the pressure of oxygen supplied from the oxygen supply source is applied to the diaphragm of the pressure sensor by opening the automatic open / close valve, and when the automatic open / close valve is next closed, the pressure sensor immediately It is necessary to be able to trace the respiratory pressure waveform. For example, in the fine pressure sensor described in Patent Document 3, the response speed of the sensor is improved.

  Unlike the case where a demand regulator is used in an outdoor environment connected to an oxygen cylinder, when a demand regulator is installed inside the oxygen concentrator housing, switching between the adsorption process based on the pressure fluctuation adsorption method, the desorption process, and cooling air Due to the flow or the like, the inside of the housing is at a pressure higher or lower than the atmospheric pressure, and pressure fluctuations also occur. In order to detect the respiratory phase with a diaphragm-type pressure sensor, it is essential to refer to the atmospheric pressure as the zero point. Problems such as intrusion of dust occur.

As means for solving this problem, the following oxygen supply apparatus has been found.
[1] In a breath-synchronized oxygen supply device that separates oxygen in the air and supplies it in synchronism with the breathing of the user, a diaphragm-type differential pressure sensor that detects the breathing of the user, and a breath detection result of the differential pressure sensor An automatic on-off valve for supplying oxygen based on the differential pressure sensor comprising a diaphragm and a substrate sandwiching the diaphragm, and communicating with an air release port of the substrate and a small chamber integrated with the casing of the oxygen concentrator, An oxygen supply apparatus comprising a plurality of small holes communicating with outside air in a casing wall of the small chamber.
[2] The oxygen supply device according to 1 above, wherein a plurality of air holes having a diameter of 0.3 mm to 2 mm are provided in a housing wall of the small chamber.
[3] The small chamber comprises a rectangular parallelepiped having a four-sided wall integrally formed with the housing wall, and a lid provided with a connection nozzle connected to the air release port of the differential pressure sensor connected via an airtight material. The oxygen supply device according to 2 above.
[4] In a breath-synchronized oxygen supply device that separates oxygen in the air and supplies it in synchronism with the breathing of the user, a diaphragm-type differential pressure sensor for detecting the breathing of the user, and a breath detection result of the differential pressure sensor An automatic on-off valve for supplying oxygen based on the differential pressure sensor comprising a diaphragm and a substrate sandwiching the diaphragm, and an air release port of the substrate is connected to a vent hole provided in a casing of the oxygen concentrator, An oxygen supply device comprising a filter in a housing vent.

  According to the present invention, the breathing phase detection accuracy of the diaphragm type differential pressure sensor which is a breathing sensor in the oxygen concentrator is improved, and the breathing waveform can be traced faithfully. As a result, the intake time can be accurately detected, and the accuracy of supplying a predetermined amount of oxygen during the intake time can be improved.

The schematic block diagram of an oxygen supply apparatus. The structure of the chamber.

Embodiment examples of the oxygen supply apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic apparatus configuration diagram illustrating a pressure fluctuation adsorption type oxygen concentrating apparatus according to an embodiment of the present invention. Such an oxygen concentrator has a compressor for supplying pressurized air, adsorption cylinders A and B filled with an adsorbent that selectively adsorbs nitrogen over oxygen, a flow for switching sequences such as an adsorption process, a desorption process, and a pressure equalization process. Supply valves A and B, exhaust valves A and B, and pressure equalization valves, which are path switching means, are provided. The oxygen-enriched gas separated and generated from the pressurized air is adjusted to a predetermined flow rate by an ON / OFF valve and then supplied to the user using a cannula.

  First, raw material air taken in from the outside is taken into the apparatus through an air intake port provided with an external air intake filter or the like for removing foreign matters such as dust. At this time, the normal air contains 1.2% of about 21% oxygen gas, about 77% nitrogen gas, 0.8% argon gas, carbon dioxide and other gases. In such an apparatus, only oxygen gas necessary as a breathing gas is concentrated and extracted.

Extraction of the oxygen-enriched gas is targeted by supply valves A and B and exhaust valves A and B with respect to an adsorption cylinder filled with an adsorbent made of zeolite or the like that selectively adsorbs nitrogen molecules rather than oxygen molecules. While the adsorption cylinders A and B are sequentially switched, the raw material air is pressurized and supplied by a compressor, and approximately 77% nitrogen gas contained in the raw material air is selectively adsorbed and removed in the adsorption cylinder. As such an adsorbent, molecular sieve zeolite such as 5A type, 13X type, and Li-X type can be used.
The adsorption cylinder is formed of a cylindrical container filled with an adsorbent. Usually, a multi-cylinder type of three or more cylinders is used in addition to the one-cylinder type and the two-cylinder type. In order to produce oxygen-enriched gas from the above, it is preferable to use a two-cylinder or multi-cylinder type adsorption cylinder.

As the compressor, a two-head type oscillating air compressor is used as a compressor having only a compression function or a compression / vacuum function, and a rotary air such as a screw type, a rotary type, a scroll type or the like. A compressor may be used. Further, the power source of the electric motor that drives the compressor may be alternating current or direct current.
In the pressurized adsorption cylinder, nitrogen gas in the air is adsorbed by the adsorbent, and oxygen-enriched gas mainly composed of oxygen that has not been adsorbed is taken out from the end of the adsorption cylinder so that it does not flow back to the adsorption cylinder. It flows into the product tank through a check valve provided.

  On the other hand, the nitrogen gas adsorbed by the adsorbent filled in the adsorption cylinder needs to be desorbed and purged from the adsorbent in order to adsorb the nitrogen gas again from the newly introduced raw material air. For this purpose, the adsorption cylinder is connected to the exhaust line via the exhaust valve, switched from the pressurized state to the atmospheric release state, the nitrogen gas adsorbed in the pressurized state is desorbed and exhausted to the atmosphere, and the adsorbent is removed. Let it play. Furthermore, in this desorption process, in order to increase the nitrogen desorption efficiency, a part of the oxygen-enriched gas generated from the product end side of the adsorption cylinder in the adsorption process is returned to the adsorption cylinder in the desorption process through the pressure equalizing valve as a purge gas. A purge process is performed.

  The oxygen-enriched gas stored in the product tank contains high-concentration oxygen gas, for example, 95%, and the patient himself sets the oxygen flow rate required by the doctor's prescription. The pressure and supply flow rate are controlled by the pressure regulating valve and ON / OFF valve, and a prescribed amount of oxygen-enriched gas is supplied to the patient. On the other hand, the flow rate and oxygen concentration of the oxygen-enriched gas supplied to the patient are detected by an oxygen concentration sensor and a flow rate sensor. Control and control oxygen production.

  The oxygen concentrator of the present invention is equipped with a demand regulator function, the respiration sensor detects the respiration phase of the user through the cannula which is an open type oxygen supply interface, and opens the ON / OFF valve in accordance with the inspiration phase. Supply oxygen. The oxygen supply amount is adjusted and supplied according to the set flow rate set by the flow rate setting unit and the open time of the ON / OFF valve according to the breathing frequency of the user. However, it is also possible to supply oxygen by adjusting the open time of the ON / OFF valve only by the set flow rate regardless of the breathing frequency of the user.

  A pressure sensor, a flow sensor, a temperature sensor (thermocouple), or the like can be used as a breathing sensor that is a user's breathing phase detection means. When a pressure sensor is used, an absolute pressure sensor or a differential pressure sensor is used. be able to. However, the response speed of the temperature sensor (thermocouple) is slow due to its heat capacity, and the flow rate sensor needs to open the other end of the cannula in order to convert the pressure change generated in the cannula by respiration into a flow rate. Sensors have the disadvantage of being affected by atmospheric pressure fluctuations. Therefore, in the embodiment of FIG. 1, a differential pressure sensor having excellent response speed and respiratory phase detection accuracy is used as the respiratory sensor.

  As the differential pressure sensor, for example, a differential pressure sensor having a structure disclosed in JP-A-2004-242906 can be used. The differential pressure sensor of FIG. 1 will be described as an example. One side of the diaphragm communicates with the gas 1 to be measured, and the other surface communicates with the gas 2 to be measured. The diaphragm is deformed by the generated differential pressure. For example, by forming a resistance circuit on the diaphragm, or by forming a capacitor with conductivity on the diaphragm surface, resistance change or capacitance change according to the amount of deformation of the diaphragm, respectively. The amount of deformation of the diaphragm according to the differential pressure can be taken out as an electric signal.

  As described above, respiration is monitored by measuring a pressure change caused by respiration that occurs at one end of a cannula, which is an open oxygen supply interface. The pressure change due to breathing always occurs as a pressure change based on the atmospheric pressure, except when a local disturbance occurs. It is necessary to keep it at atmospheric pressure. On the other hand, the differential pressure sensor is installed inside the casing of the oxygen concentrator, but the pressure inside the casing fluctuates due to the cooling fan, so the air release port is not affected by this pressure fluctuation. It is necessary to lead to a place where the atmospheric pressure that is the standard for respiratory monitoring can be referred to. In the example of FIG. 1, this is realized by connecting the atmospheric pressure release port of the differential pressure sensor to a small chamber having a vent hole communicating with the atmosphere.

  FIG. 2 shows a specific embodiment for guiding the atmospheric release port to a place where atmospheric pressure can be referred to. A box-shaped chamber configured by sharing the outer wall surface of the casing is formed in a part of the molded product that becomes the casing, and a lid provided with a tube connection port is installed on the upper surface of the box-shaped chamber. A sealed space that is not affected by pressure fluctuations inside the body can be configured. In order to increase the sealing degree of the small chamber, a gasket or an airtight material is used for the lid. For fixing the lid, screwing or a fixing method in which a fitting structure is provided on the resin part can be employed. Further, by forming the lid itself from an elastic rubber material or elastomer, it is possible to increase the degree of sealing of the small chamber without using the gasket or the airtight material. In addition, by adhering the lid to the upper surface of the box-shaped chamber, it is possible to fix the lid while increasing the sealing degree.

  In the embodiment shown in FIG. 2, a vent is provided in the outer wall surface of the housing, which is a part of the wall surface constituting the small chamber, so that the atmospheric pressure and the pressure in the small chamber are the same. Since the standard atmospheric pressure may fluctuate due to wind hitting the hole on the outer wall of the housing, the small chamber should be kept as small as possible and maintain the same pressure as the atmosphere in order to make it less susceptible to this fluctuation. Four vent holes (diameter 0.3 mm) that are sufficiently large are provided. The diameter of the air hole is preferably φ0.3 mm or more in consideration of the processability and moldability of the casing, and the size of φ2 mm or less is desirable so as not to be affected by local influences such as wind. By installing a plurality of vents that are as small as possible, the chamber has a sufficient hole area to maintain the same pressure as the atmosphere while being less susceptible to local effects such as wind. In addition, by using a plurality of air holes, the risk of the air holes being blocked by dust or the like is reduced. Further, in order to make it less susceptible to fluctuations such as wind, it is possible to adopt a method of installing a filter outside or inside the ventilation hole or a method of filling a small chamber with a porous foam.

  By connecting the port provided on the lid of the small chamber configured in this way to the atmospheric pressure release port of the differential pressure sensor, it is possible to keep the atmospheric pressure release port, which is the measurement standard of the differential pressure sensor, at atmospheric pressure. It becomes.

Claims (4)

  In a breath-synchronized oxygen supply device that separates oxygen in the air and supplies it in synchronism with a user's breath, a diaphragm-type differential pressure sensor that detects the breath of the user, and oxygen based on a breath detection result of the differential pressure sensor An automatic on-off valve for supplying the gas, and the differential pressure sensor is composed of a diaphragm and a substrate sandwiching the diaphragm, and communicates with an air release port of the substrate and a small chamber integrated with the casing of the oxygen concentrator. An oxygen supply device comprising a plurality of ventilation holes communicating with outside air in a housing wall.   The oxygen supply apparatus according to claim 1, wherein a plurality of air holes having a diameter of 0.3 mm to 2 mm are provided in a housing wall of the small chamber.   The small chamber comprises a rectangular parallelepiped having a four-sided wall integrally formed with a housing wall, and a lid portion having a connection nozzle connected to an air release port of the differential pressure sensor connected via an airtight material. 3. The oxygen supply device according to 1 or 2.   In a breath-synchronized oxygen supply device that separates oxygen in the air and supplies it in synchronism with a user's breath, a diaphragm-type differential pressure sensor that detects the breath of the user, and oxygen based on a breath detection result of the differential pressure sensor An automatic on-off valve for supplying a pressure sensor, the differential pressure sensor comprising a diaphragm and a substrate sandwiching the diaphragm, and an air release port of the substrate is connected to a vent hole provided in a housing of the oxygen concentrator and connected to the housing. An oxygen supply device comprising a filter in a pore.