JP2005218606A - Oxygen concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized pressure-swing absorption type oxygen concentrator of a very low noise level. <P>SOLUTION: In order to reduce the noise caused by inhalation and exhalation of a air supply device, the oxygen concentrator is equipped with an expansion type silencer in which the inflow pipe branches into two just before they are introduced into the silencer, and each inlet port of which is attached to a face corresponding to an expansion chamber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pressure fluctuation adsorption type oxygen concentrator using an adsorbent that preferentially adsorbs nitrogen over oxygen, and is used particularly for oxygen inhalation therapy performed on patients with chronic respiratory diseases and the like. The present invention relates to a medical oxygen concentrator. More specifically, the present invention relates to an oxygen concentrator equipped with a silencing function for reducing noise.

  In recent years, the number of patients suffering from respiratory organ diseases such as asthma, emphysema and chronic bronchitis has been increasing, and one of the most effective treatment methods is oxygen inhalation therapy. Such oxygen inhalation therapy is to allow a patient to inhale oxygen gas or oxygen-enriched air. Oxygen concentrators for separating and concentrating oxygen in the air, liquid oxygen, oxygen gas cylinders, etc. are known as oxygen supply sources used for treatment. However, because of convenience during use and ease of maintenance, it is particularly useful at home. Oxygen concentrators are mainly used for oxygen inhalation therapy.

The oxygen concentrator is a device that concentrates about 21% oxygen in the air to a high concentration and supplies it to a user. For this, a membrane oxygen concentrator using an oxygen-enriched membrane that selectively permeates oxygen And a pressure fluctuation adsorption type oxygen concentrator using an adsorbent capable of preferentially adsorbing nitrogen or oxygen such as 5A-type zeolite, 13X-type zeolite, Li-zeolite, etc., and high concentration oxygen of 90% or more can be obtained. Therefore, the pressure fluctuation adsorption type oxygen concentrator is the mainstream of the medical oxygen concentrator.
JP-A-10-245203

  The pressure fluctuation adsorption type oxygen concentrator uses an air supply device that compresses and supplies raw material air and a discharge device for discharging unnecessary gas other than oxygen concentrated in the adsorption bed. The exhaust noise is loud, and the reduction of such noise has been desired.

  In order to reduce the noise of the oxygen concentrator, for example, an oxygen concentrator having an expansion silencer described in Japanese Patent Laid-Open No. 10-245203 is used, but the silencer can be reduced in size and weight while ensuring sufficient silencing performance. As the process proceeds, the expansion ratio when flowing into the expansion chamber of the silencer and the reduction ratio when flowing out of the expansion chamber increase, resulting in an increase in pressure loss, resulting in a decrease in oxygen concentration and an increase in power consumption. .

  The present invention has been made in view of the above situation. In the pressure fluctuation adsorption type oxygen concentrator, the noise accompanying the intake / exhaust of the air supply device can be reduced while being a small and light silencer with low pressure loss. An object of the present invention is to provide an oxygen concentrator that can be sufficiently reduced.

  As a result of intensive studies to solve such problems, the present inventor has found an oxygen concentrator having the following silencing function.

  That is, the present invention is a pressure fluctuation adsorption type oxygen concentration system comprising at least one adsorption bed filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, and an air supply means for supplying raw air to the adsorption bed. In the apparatus, the muffler is an expansion-type muffler, and the oxygen is provided with a muffler that is branched into two immediately before the inflow pipe flows into the muffler and each inlet is attached to the opposite surface of the expansion chamber. A concentrating device is provided.

  Further, according to the present invention, the two inflow pipes into which the silencer flows are set so that the difference in the distance from the branch to the inlet becomes a half wavelength of the noise to be silenced. An oxygen concentrator having a vessel is provided.

  The present invention can provide an oxygen concentrator that generates a small amount of noise and that can sufficiently reduce the noise associated with intake and exhaust of an air supply device, while being a compact and lightweight silencer with low pressure loss.

  A preferred embodiment of the oxygen concentrator of the present invention will be described with reference to the drawings. The oxygen concentrator of the present invention is an apparatus that separates oxygen in the air and supplies high-concentration oxygen. For example, molecular sieve zeolite 5A, 13X, or lithium-based adsorbent that can selectively adsorb nitrogen from oxygen. This is a pressure fluctuation adsorption type oxygen concentrator that takes out oxygen by filling zeolite or the like into an adsorption bed and supplying pressurized air produced by a compressor to the adsorption bed.

  FIG. 1 is a schematic view of a silencer used in the oxygen concentrator of the present invention. The gas flow accompanied by noise is branched into the inflow pipe 3 and the inflow pipe 4 immediately before flowing into the expansion chamber 1, and the gas flows in from the opposing surfaces of the expansion chamber 1. Since gas flows into the expansion chamber 1 from the two inflow pipes, the pressure loss can be suppressed to be lower than that at the time of one.

  In the case of the expansion silencer, the noise attenuation ratio is determined by the hole diameter of the pipe into which the gas flows in, the hole diameter of the pipe through which the gas flows out, and the cross-sectional area ratio of the expansion chamber. Inflowing the gas from the air leads to a reduction in the cross-sectional area ratio, and the attenuation ratio becomes smaller than in the case of inflowing from one place, and noise in the low frequency band cannot be sufficiently silenced. Therefore, the difference in length between the inflow pipe 3 and the inflow pipe 4 is set to 1/2 the wavelength of the dominant frequency in the low frequency band, and the pressure loss is canceled by canceling out the sound wave flowing into the expansion chamber 1. It is possible to increase the noise attenuation ratio while keeping the value low.

  In the case of a pressure fluctuation adsorption type oxygen concentrator, such a silencer is installed in an intake pipe that flows raw material air into the compressor as an intake side silencer, or an exhaust pipe that exhausts desorbed air from the adsorption bed as an exhaust side silencer Can be installed. FIG. 1 shows a silencer for exhaust noise of the air supply device, but it can also be used for a silencer for intake noise of the air supply device by reversing the gas flow. .

[Example 1]
As an example of the above, in the silencer shown in FIG. 1, the inner diameter of the expansion chamber 1 is φ36 mm, the length of the expansion chamber 1 is 100 mm, the diameter of the inlet hole of the inlet pipes 3 and 4 is φ3 mm, 600 Hz (in the 1/3 octave band) In order to reduce noise in the vicinity of 630 Hz, a silencer is created by connecting a pipe with a length of the inlet pipe 3 of 15 mm, a length of the inlet pipe 4 of 315 mm, and an outlet hole diameter of 3 mm, and an air supply source to the silencer A vacuum pump was installed on the outflow pipe 5 side and operated at a rotational speed of 3300 rpm.

[Comparative Example 1]
In order to compare with the above-mentioned Example 1, in the silencer shown in FIG. 2, a silencer in which pipes having an expansion chamber diameter of 36 mm, an expansion chamber length of 100 mm, an inflow hole diameter of 3 mm, and an outflow hole diameter of 3 mm was connected was created. The same vacuum pump as 1 was operated under the same conditions, and a noise comparison experiment and a pressure loss generated by the silencer were measured.

[Comparative Example 2]
For comparison with the first embodiment, in the silencer shown in FIG. 2, the expansion chamber diameter is 36 mm, the expansion chamber length is 100 mm, and the inflow hole diameter and the expansion chamber diameter are made equal to those of the first embodiment. A silencer having a hole diameter of Φ4.2 mm and an outflow hole diameter of Φ3 mm was prepared, the same vacuum pump as in Example 1 was operated under the same conditions, and a noise comparison experiment and pressure loss generated by the silencer were measured.

  For noise measurement, an ordinary sound level meter (manufactured by RION, model NL-05) was used to measure the 1/3 octave band sound pressure level in an environment of a typical Western room with background noise of 25 dB (A) or less. And the noise level of the silencer of the comparative example was compared. The pressure loss was measured using a Copal Electronics pressure gauge (PG-30 101R). The results are shown in FIGS.

  When the cross-sectional area ratio of the inflow pipe and the expansion chamber is set to substantially the same level, the diameter of one inflow pipe is reduced by using a branch pipe as in the first embodiment of the present invention. The noise level can be reduced. Although the noise level is reduced simply by reducing the diameter of the inflow pipe as in Comparative Example 1, the pressure loss increases as shown in FIG. 4, and the inflow pipe of Example 1 according to the embodiment of the present invention is provided at two locations. It was confirmed that the noise of 600 Hz can be reduced by reducing the difference between the two pipe lengths to 1/2 wavelength with respect to the problem of pressure loss and noise in the low frequency range below 1 kHz where noise is conspicuous and difficult to mute. .

The silencer which the oxygen concentrator which concerns on embodiment of this invention has is shown. The expansion type silencer which the oxygen concentrator concerning a prior art has is shown. The 1/3 octave band sound pressure level when the silencer of FIGS. 1 and 2 is used is shown. The pressure loss which generate | occur | produces with a silencer when the silencer of FIG. 1 and FIG. 2 is used is shown.

Explanation of symbols

1 Expansion chamber 2 Inflow pipe 3 Inflow pipe A
4 Inflow pipe B
5 Outflow pipe

Claims (2)

  At least one adsorption bed filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, air supply means for supplying raw air to the adsorption bed, and for reducing the intake and exhaust noise of the air supply means In a pressure fluctuation adsorption type oxygen concentrator equipped with a silencer, the silencer is an expansion silencer, and the inflow pipe is branched into two immediately before flowing into the silencer, and each inlet is connected to the expansion chamber. An oxygen concentrator having a silencer mounted on opposite surfaces.   The two inflow pipes into which the silencer flows have a silencer that is set such that a difference in distance from the branch to the inlet is a half wavelength length of noise to be silenced. Item 2. The oxygen concentrator according to Item 1.

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