JP4685463B2 - Rotating valve - Google Patents

Description

  The present invention relates to a rotary valve that switches a fluid flow path by a sliding rotary motion of a rotor and a stator, and further relates to a pressure fluctuation adsorption oxygen concentrator that separates oxygen in the air and supplies oxygen to patients with respiratory diseases. The present invention relates to a rotary valve that switches a flow path.

  In recent years, there has been an increase in the number of patients suffering from respiratory diseases such as emphysema and chronic bronchitis. One of the most effective treatments is oxygen inhalation therapy, in which oxygen-enriched gas is directly applied from the air. Separating oxygen concentrators have been developed, and are becoming increasingly popular as treatment devices for oxygen inhalation therapy because of convenience during use and ease of maintenance.

  As such an oxygen concentrator, an adsorption-type oxygen concentrator filled with an adsorbent capable of selectively adsorbing nitrogen is known, and in particular, a pressure fluctuation adsorption-type oxygen concentrator using an air compressor as an air supply means is used at home. Used as a device for oxygen inhalation therapy. Such an apparatus usually obtains an oxygen-enriched gas by supplying compressed air from a compressor to one or a plurality of adsorption beds filled with an adsorbent capable of selectively adsorbing nitrogen to adsorb nitrogen in a pressurized state. The adsorption process and the desorption process that desorbs nitrogen by reducing the internal pressure of the adsorption bed and regenerates the adsorbent are repeated in a certain cycle, and if necessary, the dried oxygen-enriched gas that has already been generated immediately before the completion of the desorption process Is a device that obtains oxygen-enriched gas by sequentially performing a constant cycle by adding a pressure equalization step for the purpose of improving the regeneration efficiency and increasing the pressure by partially backflowing. Usually, the flow is to switch the supply path of pressurized air to the adsorption bed by connecting the compressor and the adsorption bed with piping and installing a valve means between them. There was a problem that the increase and the trouble occurred in the maintenance.

  Modularization that supplies pressurized air to the adsorbent bed through a fluid separation device with a built-in rotary valve described in JP 7-508205 A or JP 2004-209263 A as a device for improving these problems. There are also oxygen concentrators. In order to use such an oxygen concentrator for home use and medical use, it is essential to reduce the size of the device. The structure of the rotary valve and the fixed valve portion of the mechanical seal used in such a fluid separation device is In order to reduce the size of the module, it is difficult to take a sufficient mechanism space in the valve. On the mechanical seal mechanism, it is provided on the rotary shaft side and is a non-rotating rotor that is a sliding member that rotates with the rotary shaft. The stator provided on the housing side is configured to prevent fluid leakage from the shaft periphery by sliding with the surface orthogonal to the shaft in close contact with the shaft. A structure is applied in which an axial load is applied to the heart.

JP 7-508205 A JP 2004-209263 A

  Normally used mechanical seals use a lubricant such as lubricating oil to reduce the sliding resistance of the sliding surface. However, this type of lubricating oil is used for valves that change the flow path of breathing gas such as oxygen concentrators. Can not be used. Therefore, in order to improve the slidability of the valve, it is designed to suppress the sliding resistance by making the flatness of the sliding surface extremely smooth.

  When the inventor of the present application connects a condensable gas such as pressurized air containing moisture to such a valve, a phenomenon occurs in which liquid such as moisture aggregates in the flow path, and a minute amount of liquid is generated on the sliding surface. It has been found that the surface tension temporarily becomes dominant, the sliding resistance becomes very large, and causes an increase in rotational torque. Such a problem does not occur if a motor having a rotational torque exceeding the torque increase is used. However, in a device that rotates with the minimum torque due to the downsizing of the device, the operation in a high humidity environment is not possible. Reduces speed and causes stoppage.

The present invention provides the following rotary valve and an oxygen concentrator equipped with the rotary valve as means for solving the above problems.
That is, the present invention comprises a stator having at least one port hole connected to the fluid flow path on the surface, and a rotor having a connection flow path on the surface for switching the connection between the port holes by the rotational movement. In the rotary valve that switches the connection between the fluid flow paths by rotating the stator and the rotor while sliding the surface having the port hole and the surface having the connection flow path as a sliding surface, Provided is a rotary valve characterized in that a closed system groove is provided on a sliding surface of the rotor at a position where the port holes are not connected to each other during sliding and not connected to the connection flow path. .

  The present invention is also characterized in that the rotary valve switches a gas flow path having condensability, and the groove portion is provided around the flow path of the condensable gas. There is provided a rotary valve characterized by being a valve for switching air contained therein, wherein the groove portion is provided around a pressurized flow path of the air.

The present invention, in that the connection channel consists of a flow path connecting with the back portion after sliding surface between the plurality of openings and the openings provided in the same radius of the sliding surface of the rotor A rotary valve characterized in that the groove is provided in a region of the rotor having the same radius as the opening, and the groove is constituted by a single recess or a plurality of dimples. A rotary valve is provided.

  Further, the present invention is characterized in that a plurality of dimples are provided on the sliding surface of the stator, and in particular, the diameter of the dimple is smaller than the gap between the connecting flow paths on the opposed rotor sliding surfaces. A rotary valve is provided.

  Further, the present invention provides a stator having at least one port hole connected to the fluid channel on the surface, a connection channel for switching the connection between the port holes by the rotational motion, and the connection channel on the surface. And the stator and the rotor are rotated while sliding with the surface having the port hole and the surface having the connection flow path as sliding surfaces, thereby connecting the fluid flow paths to each other. In the rotary valve to be switched, the rotary valve has a closed groove on the stator sliding surface at a position where the fluid passage is not connected to the port hole while sliding. I will provide a.

  Furthermore, the present invention provides a user with an adsorption bed filled with an adsorbent capable of selectively adsorbing nitrogen over oxygen, air supply means for supplying pressurized air to the adsorption bed, and oxygen-enriched air generated from the adsorption bed. In the pressure fluctuation adsorption type oxygen concentrating apparatus provided with the oxygen supply means for supplying, at least one port hole connected to the fluid flow path is provided in the flow path for supplying the pressurized air from the air supply means to the adsorption bed. A rotation valve comprising a stator having a surface and a rotor having a connection flow path for switching the connection between the port holes by its rotational movement, and the rotation valve includes the stator and the rotor, respectively. A rotary valve that switches the connection between the fluid flow paths by rotating while sliding with the surface having the port hole and the surface having the connection flow path as a sliding surface is provided on the sliding surface of the rotor. , Not connected to the connection flow path And a pressure fluctuation adsorption type oxygen concentrator characterized by being a valve having a closed groove at a position where the port holes are not connected to each other during sliding.

The present invention is made from the flow path in which the connecting channel is connected at the back portion after sliding surface between the plurality of openings provided on the same radius of the sliding surface and the opening of the rotor, There is provided a pressure fluctuation adsorption type oxygen concentrator characterized in that the groove is provided in a region of the rotor having the same radius as the opening.

  In the oxygen concentrator equipped with the rotary valve of the present invention, it is possible to suppress fluctuations in the sliding resistance of the rotary valve even when the operating environment changes between a low humidity environment and a high humidity environment. Stable operation can be realized.

  The rotary valve of the present invention includes a stator having at least one port hole connected to a fluid flow path on the surface, and a rotor having a connection flow path on the surface for switching the connection between the port holes by the rotational movement. A rotary valve for switching the connection between the fluid flow paths by rotating the stator and the rotor while sliding with the surface having the port hole and the surface having the connection flow path as sliding surfaces It is. The shape of the flow path can take various shapes depending on the number of ports. A feature of the rotary valve of the present invention is that it does not connect to the connecting flow path on the rotor on the sliding surface of the rotor, and at the same time does not connect the port holes on the stator side facing each other during sliding. By having a closed groove at the position, the sliding area is reduced and the sliding resistance is suppressed.

  Such a rotary valve is particularly effective when switching a gas flow path having a condensable property such as air containing moisture, and the position of the groove is switched around the flow path of the condensable gas, particularly air containing water vapor. In the case of a valve, by providing a groove around the air pressure flow path, it is possible to prevent an increase in torque when condensed water is generated.

When the number of ports is small, such a rotary valve is provided with a long groove connection channel on the rotor surface, but when the number of ports is large, the rotary valve has a plurality of openings on the same radius of the sliding surface of the rotor, It may be a flow path connecting the opening at the back portion after sliding surface. In this case, the groove is provided in the region of the rotor having the same radius as the opening.

  The groove portion may be a single recess, or may be composed of a plurality of recesses and a large number of dimples, and includes all these configurations. Although it is possible to provide the smooth sliding surface later by machining, a rotor having a concave portion as a groove portion can be formed by providing a convex portion of, for example, 0.5 mm on a predetermined mold. In addition, when dimples are provided, they can be formed by providing predetermined convex portions at the dimple locations of the mold. For example, in a circular dimple, the pitch between the dimples is set to 2 mm or more, and dimples having a diameter of, for example, 0.5 to 1.2 mm are provided therebetween.

  The rotor and stator, which are sliding members of the rotary valve of the present invention, are required to have excellent wear resistance and sliding characteristics. The material of the sliding material is a super-hard material such as tungsten carbide having excellent wear resistance. Hard materials such as hard alloys, silicon carbide, and alumina, and carbon having excellent self-lubricating properties can be used.

  Such a groove portion not only reduces the sliding area but also has an effect of removing dust and the like from the sliding portion. Therefore, the groove portion can be provided on the rotor side and a plurality of dimples can be provided on the rotor-side sliding surface. In this case, it is a condition that the diameter of the dimple is smaller than the gap between the connecting flow paths on the opposed rotor sliding surfaces.

  The groove may be provided not only on the rotor side but also on the stator side. Therefore, a stator having at least one port hole connected to the fluid flow path on the surface and having a configuration opposite to that of the above-described rotary valve, and a connection flow for switching the connection between the port holes by the rotational motion. A rotor having a path and a connection channel on the surface, the stator and the rotor rotating while sliding with the surface having the port hole and the surface having the connection channel as a sliding surface, respectively. In the rotary valve for switching the connection between the fluid flow paths, the closed system groove portion is not connected to the port hole on the stator sliding surface and is not connected to the fluid flow paths during sliding. It is also possible to provide a rotary valve characterized by having

  The rotary valve of the present invention is applicable to a pressure fluctuation adsorption type oxygen concentrator. That is, an adsorption bed filled with an adsorbent capable of selectively adsorbing nitrogen rather than oxygen, air supply means for supplying pressurized air to the adsorption bed, oxygen for supplying oxygen-enriched air generated from the adsorption bed to the user A pressure fluctuation adsorption type oxygen concentrator provided with a supply means, having a rotary valve in a flow path switching valve, and in particular, in a flow path for supplying pressurized air from an air supply means such as a compressor to the adsorption bed The rotary valve of the present invention is provided.

A preferred embodiment of the rotary valve of the present invention will be described in detail with reference to the drawings.
In the embodiment shown in FIG. 1, a four-cylinder adsorption type medical oxygen concentrator is used as the medical gas generating means 1. The air supplied to the compressor 12 through the filter 13 is compressed and enters the adsorption cylinder 11 through the rotary valve 14. The compressed air that has entered the adsorption cylinder 11 is selectively adsorbed with nitrogen, and the remaining oxygen that has not been adsorbed passes through the product tank 15 through the flow rate setting device 16, the product filter 17, and the humidifier 18 from the oxygen concentrator. To be supplied. The rotary valve 14 simultaneously supplies compressed air to the adsorption cylinder 11, transports nitrogen desorbed from the adsorbent to the compressor 12, and supplies concentrated oxygen to the product tank 15.

  As shown in FIG. 2, the rotary valve 14 includes a rotor and a stator. The stator is connected to the compressor 12, the adsorption cylinder 11, and the product tank 15, and the rotor switches the flow paths of compressed air, nitrogen, and concentrated oxygen while rotating and sliding on the stator. In a preferred embodiment, resin impregnated graphite (product number CTI-25, manufactured by CTI) is used as the rotor material, alumina (product number 965, manufactured by Matroc) is used as the stator material, and a brushless DC gear motor is used as the rotor drive source. . Since pressure by compressed air is applied to the inside of the rotary valve, the rotor was pressed with a spring in the direction of the stator so that the rotor was not separated from the stator.

  FIG. 3 shows the sliding surfaces of the rotor and the stator. In order to prevent gas leakage, the rotor sliding surface was polished to a flatness of 2 μm and surface roughness Ra of 0.1 μm, and the stator sliding surface was polished to a flatness of 1 μm and surface roughness Ra of 0.15 μm. In the rotor sliding surface of FIG. 3, the shaded portion is a channel switching port, and the blackened portion is a groove having a depth of 0.5 mm from the sliding surface. The groove is not connected to any channel switching port. In the stator sliding surface of FIG. 3, the hatched portion is a port connected to any of the compressor, suction cylinder, and product tank, and the blackened portion is a groove having a depth of 0.5 mm from the sliding surface. The groove is not connected to any channel switching port. Such grooves are not involved in the gas flow path switching function that the rotary valve originally has, reduce the sliding area, and drain the wear powder generated by the sliding from the sliding surface into the groove, thereby sliding the rotary valve during rotation. The purpose is to reduce the dynamic friction torque. In this embodiment, the grooves are provided on the outer edge of the rotor and the stator far from the center of rotation of the sliding surface. The reason for this will be described below.

  By sliding between the rotor and the stator, the resin-impregnated graphite, which is the material of the rotor, is worn mainly, generating wear powder on the sliding surface and reducing the surface roughness of the rotor sliding surface. Accumulation of wear powder on the sliding surface contributes to an increase in the sliding friction coefficient. In addition, when the compressed air supplied from the compressor 12 is condensed near the sliding surface, the surface tension of water contributes to an increase in the sliding friction coefficient, and the smaller the surface roughness of the sliding surface, the higher the friction coefficient during condensation. Is remarkable. That is, as wear progresses, wear powder accumulation on the sliding surface and sliding friction coefficient increase due to sliding surface condensation become more prominent. The wear rate depends on the distance from the valve rotation center and the relative humidity near the sliding surface. The greater the distance from the center of rotation, the higher the relative humidity near the sliding surface, the greater the wear rate. In the oxygen concentrator used in the present embodiment, only compressed air has the possibility of condensation in the vicinity of the sliding surface among compressed air, concentrated oxygen, and nitrogen, and the flow path of the compressed air is limited to this embodiment. Only the outer edge of the sliding surface of the rotary valve. Therefore, in this embodiment, the outer edge portion of the rotary valve sliding surface is significantly worn and the sliding friction coefficient is increased, so that the area reduction of the outer edge portion of the rotary valve sliding surface greatly reduces the rotational load torque of the rotary valve. I thought it would contribute.

  FIG. 4 shows a change in rotational load torque of the rotary valve when the oxygen concentrator is continuously operated in a hot and humid environment. Ambient temperature and humidity are 35 ° C., 95% RH, the rotation speed of the rotary valve is 3 rpm, and the operation time is 130 to 260 hours. The number of units operated is five, three of which have the grooves shown in FIG. 3 at the outer edge of the sliding surface of the rotary valve, and the other two have no grooves. In addition, 1 plot in FIG. 4 is an average value for 1 hour. In the two units without grooves, the valve rotational load torque continued to increase remarkably from the start of operation, whereas in the three units with grooves, the rotational load torque increased slowly, confirming the effect of installing the grooves.

The temperature / humidity cycle test shown in FIG. 5 clearly shows the effect of the groove installation. There are two types of ambient temperature and humidity of 20 ° C. and 50% RH and 35 ° C. and 95% RH, and the temperature and humidity were switched about every hour. The rotational speed of the rotary valve is 3 rpm, and the given number of temperature and humidity cycles is 10-15. The number of operating oxygen concentrators is two, one with and without a groove on the valve sliding surface. The graph of FIG. 5 is a plot of instantaneous values of valve rotational load torque. In the case without a groove, the valve rotation load torque greatly fluctuated as the temperature and humidity increased and decreased, and the peak value increased remarkably as the number of temperature and humidity cycles increased. On the other hand, the rotational load torque was not easily affected by changes in temperature and humidity in the device with a groove, and no significant increase in the rotational load torque peak value with an increase in the number of cycles was observed.

  For mechanical seals, select a region where the friction coefficient is likely to increase as in the present invention even if there are restrictions on the finish of the sliding surface and the surface pressure of the sliding surface from the viewpoint of ensuring fluid sealing performance. In addition, sliding friction can be reduced by installing a groove. The rotary valve of the present invention makes it possible to extend the life of the sliding component and the sliding component drive source, and to reduce the weight and cost of the sliding component drive source.

The preferred embodiment example of the rotary valve of this invention. The schematic diagram of the rotary valve of this invention. The schematic diagram of the rotary valve sliding surface of this invention. Changes over time in rotational load torque when the rotary valve is operated continuously in a hot and humid environment. Variation diagram of humidity cycle and valve rotation load torque.

Explanation of symbols

1. 10. Medical gas generating means Adsorption cylinder 12. Compressor 13. Filter 14. Rotating valve 15. Product tank 16. Flow rate setting device 17. Product filter 18. humidifier

Claims (9)

A stator having at least one port hole connected to the fluid flow path on the surface, and a rotor having a connection flow path on the surface for switching the connection between the port holes by the rotational movement; In the rotary valve that switches the connection between the fluid flow paths by rotating while rotating the surface having the port hole and the surface having the connection flow path as a sliding surface,
On the sliding surface of the rotor, it has a groove part of a closed system at a position where it is not connected to the connection flow path and the port holes are not connected to each other during sliding,
The rotary valve is a valve for switching a flow path of air containing water vapor;
Rotating valve groove portion is closed in the flow path around the air, characterized in that it does not use a lubricating oil to the sliding surface.   2. The connection flow path includes a plurality of openings provided on the same radius of the sliding surface of the rotor and a flow path connecting the openings at the back of the sliding surface. Rotating valve as described in   The rotary valve according to claim 1, wherein the groove is provided in a region of the rotor having the same radius as the opening.   The rotary valve according to any one of claims 1 to 3, wherein the groove portion is composed of a single concave portion or a plurality of dimples.   The rotary valve according to any one of claims 1 to 4, further comprising a plurality of dimples on a sliding surface of the stator.   6. The rotary valve according to claim 5, wherein the diameter of the dimple is smaller than a gap between connection flow paths on the opposed rotor sliding surfaces. A stator having at least one port hole connected to the fluid flow path on the surface, and a rotor having a connection flow path on the surface for switching the connection between the port holes by the rotational movement; In the rotary valve that switches the connection between the fluid flow paths by rotating while rotating the surface having the port hole and the surface having the connection flow path as a sliding surface,
On the stator sliding surface, a closed system groove is provided at a position where the fluid passage is not connected to the port hole and not connected to the port hole during sliding,
The rotary valve is a valve for switching a flow path of air containing water vapor;
Rotating valve groove portion is closed around the boosted channel of the air, characterized in that it does not use a lubricating oil to the sliding surface.   An adsorption bed filled with an adsorbent capable of selectively adsorbing nitrogen over oxygen, an air supply means for supplying pressurized air to the adsorption bed, and an oxygen supply means for supplying oxygen-enriched air generated from the adsorption bed to the user In the pressure fluctuation adsorption type oxygen concentrator equipped with the above-mentioned, the rotary valve according to any one of claims 1 to 6 is provided in a flow path for supplying pressurized air from the air supply means to the adsorption bed. Pressure fluctuation adsorption type oxygen concentrator.   The connection flow path includes a plurality of openings provided on the same radius of the sliding surface of the rotor and a flow path connecting between the openings at the back of the sliding surface, and the groove portion includes the opening. The pressure fluctuation adsorption type oxygen concentrator according to claim 8, which is provided in a region of the rotor having the same radius as that of the rotor.

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