WO2019004987A2

WO2019004987A2 - Novelty of an oxygen concentrator

Info

Publication number: WO2019004987A2
Application number: PCT/TR2018/050301
Authority: WO
Inventors: Ata OZCAN
Original assignee: Ozcan Kardesler Tip Cihazlari Sanayi Ve Ticaret Limited Sirketi
Priority date: 2017-06-30
Filing date: 2018-06-12
Publication date: 2019-01-03
Also published as: TR201709651A2; WO2019004987A3

Abstract

The invention relates to the addition of a lower equalizing valve that would enable obtaining higher amounts of oxygen gas per unit time and enable energy saving by reducing cycle time of an oxygen concentrator used in medical oxygen gas generation and storage systems, wherein the pressure swing adsorption technology is utilized.

Description

Novelty of an Oxygen Concentrator Technical Field of the Invention

The present invention relates to a novelty that has been developed in an oxygen concentrator.

The invention in particular relates to addition of a lower equalizing valve that would enable obtaining more amount of oxygen gas per unit time by reducing cycle time to an oxygen concentrator used in medical oxygen gas generation and storage systems, wherein the pressure swing adsorption technology is utilized.

Prior Art

Nowadays, the medical oxygen treatment is accepted as one of the most important treatment methods of relieving the respiration systems of patients. The primary cases in which the medical oxygen treatment is a must include the acute and Chronic Obstructive Pulmonary Disease (COPD), liver disease, respiratory failure, emphysema, chronic bronchitis, severe asthma, end-stages muscle diseases, severe cystic fibrosis and heart disease and poisoning. Medical oxygen is typically generated via an oxygen concentrator that enables obtaining oxygen gas from the air and PSA (Pressure Swing Adsorption) technology is utilized. Basically, an oxygen concentrator is a device that concentrates oxygen from a gas source (typically ambient air) so as to supply an oxygen-enriched gas stream.

Oxygen concentrators typically use the pressure swing adsorption (PSA) technology. They are in particular commonly used in houses and clinics for a medical or pressure oxygen supply. Various other concentrators based on the membrane technology for other purposes have been provided as well. The oxygen concentrators are also used so as to provide an economical source for industrial processes, which have been also known as oxygen gas generators or oxygen generation plants.

In literature, "VPSA" and "PSA" are accepted as two separate methods. "VPSA"; is defined as vacuum pressure swing adsorption. In this system, oxygen is separated from the fresh air by "vacuuming". Working pressure is below 1 bar and vacuum is used in the separation process.

The oxygen obtained is also far below 1 bar. Oxygen is used at a pressure of 4 bars in hospitals, thus the "VPSA" systems are not suitable and preferable for hospitals. On the other hand, in the PSA systems, the oxygen is obtained from compressed fresh air. Working pressure is within the range of 7-13 bar and the oxygen obtained is in the range of 4-8 bars. Reference is made to the ISO 10083 PSA systems. Operational characteristics and oxygen sieves of the VPSA and PSA systems are completely different from each other.

Oxygen concentrators use a molecular sieve that contains zeolite to adsorb gases. They operate based on the principle of rapid swing adsorption of atmospheric nitrogen to zeolite minerals and subsequent aeration of the nitrogen. Therefore, this type of adsorption system is functionally a nitrogen washer that allows the other atmospheric gases to transit. The oxygen is sieved as a primary gas. The PSA technology is a safe and economical technology in small to medium-scaled oxygen generation.

In a medical oxygen generation and storage system, the compressed air provided by a compressor is sieved through dryers and filters and then is purged of particles, oils and moisture. The clean and dry air obtained enters under the adsorption bed of the oxygen concentrator in operation and proceeds upwards. Nitrogen and the small amount of transition gases contained within the air are retained by the zeolite in the adsorption bed that is in operation while the oxygen molecules are allowed to transit. When the zeolite molecules in the adsorption bed that is in operation are about to reach saturation with the gases retained, the system automatically switches between the beds depending on a predetermined period of time. When the bed that completes its regeneration process starts to operate, the bed that reaches the saturation switches to the regeneration process.

In a full cycle, the PSA process is started once the air conditioned and compressed enters a first column. Undesired gases are retained by the adsorption bed that contains zeolite at the high pressure while desired oxygen molecules pass through the adsorption bed. The oxygen gas at a high purity obtained is stored in an oxygen tank. During the adsorption process in the first column, a second column is in cleaning process. Once the adsorption bed in the first column reaches to saturation, the equalizing valve between these two columns is opened and the pressure is equalized there between. The pressure in the first column is reduced and waste gases are discharged by an exhaust system. The same process is subsequently performed in the second column. A continuous oxygen generation is provided by repeating said process between the two columns respectively.

When a literature review was carried out in the prior art regarding the field, the following references are discovered. in a Chinese utility model application with the publication number CN203781834 (U), titled "Medical modular PSA oxygen generator', a medical modular PSA oxygen generator formed of a modular adsorption separation device and a pneumatic valve piping in combination is described wherein the modular adsorption separation device is composed of two groups of modular absorption towers and a modular gas buffer tank there between. In said patent document, an oxygen generator is developed, which is small, easy to mount and carry due to its modular structure and components and which also eliminates the need for special equipment including an air cylinder and an oxygen cylinder. However, a equalizing valve that allows pressure equalization between the columns is still not provided.

Also, some systems has not any equalization valve, but these systems consume electricity 3 times more than systems which has equalization valves.

As in the aforementioned applications, developments have been carried out according to application fields and according to requirements in oxygen generation systems; however an application that suggests a lower equalizing valve has not been encountered.

Summary of the Invention

The invention in particular relates to the addition of a lower equalizing valve that would enable obtaining higher amounts of oxygen gas per unit time by reducing cycle time to an oxygen concentrator used in a medical oxygen gas generation and storage system where the pressure swing adsorption technology is utilized.

The primary aim of the invention is to develop an oxygen concentrator to be used in medical oxygen gas generation and storage systems, wherein the pressure swing adsorption technology is utilised.

Another aim of the invention is to enable obtaining higher amounts of oxygen gas per unit time by reducing the cycle time with the addition of a lower equalizing valve to the oxygen concentrator.

In order to achieve the aforementioned aims, the present invention comprises;

• a first column in which nitrogen gas in the air is adsorbed due to its molecular sieve structure containing zeolite,

• a first air valve that allows a compressed air inlet under said first column to be controlled, a first exhaust valve that allows an exhaust gas outlet under said first column to be controlled,

a second column that operates in shifts with said first column and wherein the nitrogen gas in the air is adsorbed due to its molecular sieve structure containing zeolite,

a second air valve that allows a compressed air inlet under said second column to be controlled,

a second exhaust valve that allows an exhaust gas outlet under the said second column to be controlled,

an upper equalizing valve that is located on the upper face between said first column and said second column and allows pressure equalization between these two columns,

a lower equalizing valve that promotes the pressure equalization between two columns and allows less operating time by being included in addition to said upper equalizing valve that is located on the upper face between said first column and said second column and allows pressure equalization between these two columns, wherein said components are connected to each other via a piping through which a fluid gas passes.

All structural aspects and characteristics as well as advantages of the present invention would be understood more clearly with the help of the detailed description presented below. Therefore, it will be appreciated that any assessment regarding the invention is to be made by taking this detailed description into consideration.

Drawings illustrating the Invention

Figure-1 , represents an overall diagram of a medical oxygen generation and storage system. Figure-2 , represents a detailed diagram of the oxygen concentrator according to the present invention.

Reference List of the Components

1 Medical oxygen generation and storage system

10 Oxygen concentrator

100 First column

110 First air valve

120 First exhaust valve

200 Second column 210 Second air valve

220 Second exhaust valve

300 Upper equalizing valve

400 Lower equalizing valve

(H) Air inlet

(E) Exhaust gas outlet

20 Compressor

30 Dryer

40 Air tank

50 Oxygen tank

Detailed Description of the Invention In this detailed description, an oxygen concentrator (10) according to the invention and a preferred embodiment of the same is disclosed which should not be construed to limit the linvention in any way, and which has been provided in order to ensure clear understanding of the invention. In Figure 1 , an overall diagram of the medical oxygen generation and storage system (1) is represented. In an oxygen gas generation process, the compressed air supplied by a compressor (20) is passed through a dryer (30) and thus purged from the moisture and impurities therein. The compressed air that is purged is delivered to a pressure-resistant air tank (40). The air tank (40) feeds compressed air supply to the oxygen concentrator (10). The oxygen gas obtained in the oxygen concentrator (10) is delivered to the oxygen tank (50) and is stored therein.

In Figure 2, a detailed diagram of the oxygen concentrator (10) according to the invention is shown. The invention comprises; a first column (100) in which nitrogen gas in the air is adsorbed due to its molecular sieve structure containing zeolite;a first air valve (110) that allows a compressed air inlet under said first column (100) to be controlled; a first exhaust valve (120) that allows an exhaust gas outlet under said first column (100) to be controlled;a second column (200) that operates in shifts with said first column (100) and wherein the nitrogen gas within the air is adsorbed due to its molecular sieve structure containing zeolite; a second air valve (210) that allows a compressed air inlet under said second column (200) to be controlled; a second exhaust valve (220) that allows exhaust gas outlet under the said second column (200) to be controlled; an upper equalizing valve (300) that is located on the upper face between said first column (100) and said second column (200) and allows pressure equalization between these two columns; a lower equalizing valve (400) that promotes the pressure equalization between two columns and allows less operating time by being included in addition to said upper equalizing valve (300) that is located on the upper face between said first column (100) and said second column (200) and allows pressure equalization between these two columns; which are connected to each other via a piping through which a fluid gas passes.

Generation cycle of the oxygen concentrator (10) operates based on the principle of transition between zeolite beds that are located on the first column (100) and the second column (200) and the operation cycle is comprised of two equal half-cycles.

In a first half-cycle, a compressed air supply is set to be fed under the first column (100) once the first air valve (110) located in an air inlet (H) is opened. The nitrogen gas within the compressed air entering the first column (100) is adsorbed on the zeolite bed. Oxygen gas starts to go upwards the first column (100) following its separation. Once the zeolite bed in the first column (100) is saturated with the nitrogen gas, the first air valve (110), the upper equalizing valve (300) and the lower equalizing valve (400) is opened. As the pressure within the first column (100) is reduced, the nitrogen gas that is adsorbed shifts to a free state and thus shifts to an exhaust outlet (E) once the first exhaust valve (120) is opened.

When the zeolite bed in the first column (100) is saturated with nitrogen gas, there is the fresh air from which oxygen is not separated at the lower portion of first column (100). In the prior system the fresh air at a lower portion is discharged by opening the first exhaust (120). As for the present system, the compressed fresh air within the lower portion of the first column (100) passes to the second column (200) so as to be separated once the lower equalizing valve (400) and the upper equalizing valve (300) are opened together before the first exhaust valve (120) is opened. Approximate pressure of this fresh air is at 4 bars. The compressed fresh air has been normally obtained via the compressor (20) by consuming electricity. In the present system, the compressed fresh air passes from the first column (100) to the second column (200) with pressure difference, thus without any waste of energy.

Oxygen with high purity that is present at the upper portion of the first Column (100) is allowed to pass to the second column (200) by the opening the upper equalizing valve (300) while the fresh air within the lower portion of the first column (100) is allowed to pass to the second column (200) by the opening the lower equalizing valve (400). Thus, the nitrogen gas remains in the first column (100), wherein the gas is separated from the fresh air within the middle portion of said column. Additionally, pressures of the first column (100) and the second column (200) are equalized during this time In the next period, the air intake valve (110) of the first column (100) is closed, the exhaust valve (120) of the first column is opened, and the air intake valve (210) of the second valve (200) is opened, and the exhaust valve (220) of the second column (200) is closed and thus the fresh air starts to fill in to the second column (200).

When the zeolite bed in the second column (200) is saturated with nitrogen gas, the fresh air from which oxygen is not separated is still present at the lower portion of the second column (200). The fresh air at the lower portion was discharged by opening the first exhaust (220) valve in the former system. In the present system, the compressed fresh air within the lower portion of the second column (200) passes to the first column (100) so as to be separated once the lower equalizing valve (400) and the upper equalizing valve (300) are opened together before the second exhaust valve (220) is opened. Approximate pressure of this fresh air is at 4 Bars. The compressed fresh air has been normally obtained via the compressor (20) by consuming electricity. In the present system, the compressed fresh air passes from the first column (100) to the second column (200) with pressure difference, thus without wasting energy. When the second half-cycle starts, the first column (100) remains at the cleaning process and the first exhaust valve (120) remains in an opened state. Compressed air supply is set to be fed under the second column (200) once the second air valve (210) located in an air inlet (H) is opened. The nitrogen gas in the compressed air entering the second column (200) is adsorbed on the zeolite bed and the oxygen gas starts to exit over the over the second column (200) following its separation. Once the zeolite bed in the second column (200) is saturated with the nitrogen gas, the second air valve (210) is closed, the upper equalizing valve (300) and the lower equalizing valve (400) is opened and also as the pressure within the second column (200) is reduced, the nitrogen gas adsorbed shifts to a free state and thus exits through the exhaust outlet (E) once the second exhaust valve (220) is opened. Subsequently, a new cycle is started, wherein the second column (200) remains in the cleaning process, and the first column (100) is fed with compressed air.

Claims

1. An oxygen concentrator (10) to be used in obtaining oxygen gas from air, in which a pressure swing adsorption technology is used, wherein they the following are engaged with each other via a pipe system through which fluid gas passes, comprising;

• a first column (100) in which nitrogen gas in the air is adsorbed,

• a first air valve (110) that allows a compressed air inlet under said first column (100) to be controlled,

· a first exhaust valve (120) that allows an exhaust gas outlet under said first column (100) to be controlled,

• a second column (200) that operates in shifts with said first column (100) and wherein the nitrogen gas in the air is adsorbed,

• a second air valve (210) that allows a compressed air inlet under said second column (200) to be controlled,

• a second exhaust valve (220) that allows exhaust gas outlet under the said second column (200) to be controlled,

• an upper equalizing valve (300) that is located on the upper face between said first column (100) and said second column (200) and allows pressure equalization between these two columns, characterized in that it comprises;

• said lower equalizing valve (400) that promotes the pressure equalization between two columns and enables less operating time and provides energy saving by being included in addition to said upper equalizing valve (300) that is located on the upper face between said first column (100) and said second column (200) and allows pressure equalization between these two columns.