WO1998036787A1 - Combined oxygen production and supply system - Google Patents

Abstract

The invention relates to a combined oxygen production and supply system, in particular for long-term oxygen therapy, with a device (1) for producing an oxygen- enriched product gas, with a device (2) for breathing-dependant dosing of the product gas, and with a measuring device (4) for determining the breathing activity of the patient (3), the exit of said measuring device (4) being coupled with the device (2) for supplying the product gas to the patient (3). The invention is characterized in that the exit of the measuring device (4) is situated close to the entrance of an evaluation circuit (16) for determining the actual amount of the product gas used. The signal exit of this evaluation circuit (16) is situated close to a drive circuit for the device (1) for producing the product gas. The productive capacity of the device (1) for producing the product gas is regulated in such a way that the amount of product gas produced in one time unit corresponds to the amount needed, and the signal emitted from the evaluation circuit (16) is intended to influence the amount of the product gas that is produced.

Description

title

Combined oxygen generation and oxygen supply system

FIELD OF THE INVENTION The invention relates to a combined oxygen generation and oxygen supply system, in particular for long-term human medical oxygen therapy in the patient's home environment, with a device for generating a product gas highly enriched with oxygen, with a device for supplying the product gas in a dose-dependent manner to the patient and with a measuring device for recording the breathing activity of the patient, the output of the measuring device being coupled to a control input of the device for supplying the product gas to the patient.

State of the art

The administration of oxygen to patients has long proven itself in many disease courses and after operations. With such oxygen therapies, a distinction is made between short and long-term applications depending on the duration. Caused by the increase in average age and increasing health awareness among the population and ultimately also by an increase in civilization and environmental diseases, an increase in long-term use in oxygen administration can be seen and is expected to continue. Such therapies in the form of home treatments are also increasingly being used for patients of shorter ages, if this avoids hospital stays and if necessary does not have to interrupt employment. On the one hand, this development tendency leads to demands for the further development of suitable forms of therapy, but on the other hand also demands for device technology developments that support the forms of therapy to be used. A very special challenge for the device technology is the patient's wish to receive therapy from the hospital. take out the environment and move it to the domestic area. This endeavor to maintain or regain freedom of movement is of increasing importance for the rehabilitation process and the quality of life. The increase in mobility thanks to better devices and improved usage properties of device technology is gratefully accepted by both patients and doctors.

A classic variant of the administration of oxygen is the provision in bottles and the delivery to the patient via an oxygen mask. At a filling pressure of 200 bar, a 1 O liter bottle e.g. Contain 2000 liters of pure oxygen with a purity of 99.5%. The disadvantage of this is that the bottle empties relatively quickly during use and the provision of reserve bottles is required in relatively short periods of time. For example, be required to provide a refilled bottle for each day. Oxygen lasers are also pressure vessels that are subject to the relevant safety regulations and therefore also represent a source of danger in the home. The oxygen bottles are relatively heavy, their handling is usually problematic for the patients who are also physically weak. Therefore, the main use of oxygen cylinders is primarily for short-term applications, e.g. in ambulances at accident care.

For long-term oxygen therapy, it is known to provide oxygen concentrators that can also be used in the patient's home environment. With a set flow rate of e.g. up to about 2 liters per minute the oxygen concentration is about 95%, at least 90% at a higher flow rate. Although continuous operation with simple operation is possible here, there is the disadvantage of a noise development which is often perceived as annoying and the inadequate manageability due to the relatively large mass (over 20 kg) of the oxygen concentrators used to date. In addition, a mains connection is required for these devices and a power consumption of 300 to over 500 watts can be expected.

The supply via liquid oxygen is considered to be relatively new. The corresponding medical technology can be used in both stationary and mobile areas. However, the low-noise use as an advantage is offset by disadvantages, such as the need to maintain a vertical position of the storage container, the risk of explosion if the container falls over, a complicated refilling process, high technical requirements for the safety technology and for the vascular system. system to avoid thermal bridges and gas losses due to self-heating of the liquid gas. The main reason for this technical risk is that this variant of oxygen supply has not yet become widely accepted worldwide.

In addition to the aforementioned technical facilities for providing oxygen, so-called intelligent oxygen-saving systems are known in which the oxygen supply to the patient is dosed according to the indication. How much oxygen the patient needs depends on the indication and the physical load. The oxygen supply is dosed depending on how the patient can set the flow rate using several switch positions. In addition, the patient is only operated in the most oxygen-effective phase of breathing. This takes advantage of the fact that only at the beginning of each breath does the inhaled oxygen enter the lungs for gas exchange. The remaining oxygen is used only for dead space ventilation and is exhaled again unused. The oxygen saving systems therefore ensure that the patient is not continuously supplied with oxygen during breathing, but only at the beginning of the breathing process, since the oxygen is actually effectively absorbed and converted by the body. As a result, an available volume of oxygen lasts much longer than with the continuous supply. The use of such saving systems in connection with the provision of oxygen in bottles is known.

Systems have also been developed in which both the oxygen bottle and the oxygen saving system are designed as a portable unit. However, the mass of such a facility is still very large and the range as the patient's mobility limit is narrowed in that the contents of the bottle are quickly used up. The patient must not only ensure that the bottle is refilled, but also that there is a supply of refillable oxygen.

Finally, it is also known to use oxygen concentrators in conjunction with the aforementioned oxygen-saving system in long-term oxygen therapy in the inpatient area in the hospital as well as in the patient's home area. Such a combination is shown in EP 01 88071 as a “breathing-synchronized device for supplying concentrated oxygen. This device includes an oxygen concentrator for generating and storing an oxygen-enriched breathing gas, a buffer tank which temporarily stores the oxygen-enriched breathing gas and a valve which is attached to an outlet of the buffer tank in order to block the flow of the oxygen-enriched gas from the buffer tank to the breathing to control the patient's system. The oxygen-saving system includes a sensor that is attached to the patient's breathing and is designed to generate an output signal that detects the inhalation phase and the exhalation phase of the breathing. Furthermore, an adjusting device is provided with which the relationship between the total length of the inhalation phase and its specific end section can be specified. A regulating device ensures that the duration of each inhalation phase is determined in succession, based on the output signal from the sensor, and that the valve opens at the beginning of each inhalation phase. As a result, oxygen-enriched breathing gas only reaches the patient at the beginning of each inhalation phase. The buffer tank ensures that the initial flow rate of the oxygen-enriched gas is higher than its steady-state flow rate in each inhalation phase.

Description of the invention

The invention has for its object to develop a combined oxygen generation and supply system of the type described above so that a compact structure of the entire arrangement is possible and the utility value is further improved due to simplified handling, less noise and reduced energy consumption.

According to the invention the object is achieved in that the output of the measuring device for detecting breathing activity is branched and at least one of the branches is present at the input of an evaluation circuit for the current consumption quantity of the product gas, that the signal output of this evaluation circuit is connected to a signal input of a control circuit for the device to produce the product gas, the performance of the device for producing the product gas is dimensioned such that the amount of product gas generated during normal operation in one unit of time corresponds approximately to the amount required by an average patient in the same unit of time and that by the evaluation circuit Output signal is provided to influence the amount of product gas generated per unit of time via the control circuit.

This device ensures that the product gas generation and the device for supplying the product gas to the patient form a unit in that the amount of product gas generated or the dimensioning of the generation system are carried out in such a way that only the amount of product gas is provided that the patient can consume immediately. Thereby lies the dimensioning the consumption of an average patient and there is the possibility of increasing or reducing the amount of product gas generated depending on the current consumption. Due to this direct connection between generation and patient, there is the possibility of switching to the intermediate storage of the product gas. This means that no containers are required to store the product gas. The production of the product gas and the consumption no longer take place independently of one another, but are coordinated with one another.

In a preferred embodiment of the invention it is provided that there is a compressor in the device for generating the product gas and an electric motor as the drive unit for the compressor, and that the output of the evaluation circuit is linked to the power supply unit of the electric motor. This ensures in a simple manner that the production quantity of product gas can be influenced as a function of the speed of the electric motor. If the engine is operating at high speed, the amount of product gas produced is increased, if the engine is operating at lower speed, the product gas generation is throttled.

An advantageous embodiment of the invention consists in the fact that two threshold switches are provided in the evaluation circuit, one of which outputs an increase signal when a lower setpoint is undershot and outputs a decrease signal when an upper setpoint is exceeded, in each case based on the amount used during normal operation of the product gas, caused to the control circuit for the device for generating the product gas. This evaluation circuit has a simple structure, can be implemented with little effort and reliably ensures that the normal consumption of the patient can be produced and supplied to the patient during normal operation, while increased consumption causes increased production due to the increase signal. Similarly, if the patient's breathing activity is reduced, the product gas generation is reduced.

In a preferred embodiment of the invention it is provided that in the device for generating the product gas, in addition to the compressor, there are two adsorption cylinders and a compensating tank and are connected to one another via lines, the output of the compressor being connected to each of the adsorption cylinders and via a directional valve each of the adsorption cylinders is connected to the expansion tank via a further directional valve. In this way, the air compressed in the compressor can be fed alternately to the adsorption cylinders, in which the product gas is actually extracted. Depending on the enrichment of the mated air with oxygen in the adsorption cylinders, these are connected to the expansion tank and the product gas flows into the expansion tank. The expansion tank advantageously ensures that product gas is always available under a minimum pressure required for the supply. The oxygen supply system now initiates the supply of the product gas to the patient in a manner already described, depending on the patient's breathing activity.

The device for generating the product gas can advantageously be designed with an internal performance of 0.5 to 1 liter per minute and a peak performance of 1 to 2 liters per minute. This makes it possible to Normal consumption continuously provide the amount of product gas that the oxygen supply system supplies to the patient depending on his breathing activity. In addition, it is ensured that the supply with higher consumption is possible over the period during which the patient requires a larger amount of the product gas to be supplied. It can be assumed that the increased consumption is limited in time and therefore the peak power for the device for generating the product gas does not have to become a continuous power.

A very advantageous development of the invention provides that all of the assemblies are housed together in a transportable housing, with manually operated switching elements and visually controllable monitoring elements being provided on the outside of the housing. The transportable housing should advantageously be designed as a hand case consisting of hard shells. Because of this configuration, the entire generation and oxygen supply system is extremely easy to handle and can be easily transported by the patient himself or by his companion.

The main advantage of the oxygen generation and oxygen supply system according to the invention is that due to the adapted performance, a compact structure and also the connection to energy sources of low power is possible. These can be car batteries, for example, which enable the patient not to have to do without therapy even when traveling. Connection to photoelectric solar cells is also conceivable, for example by interposing an accumulator as an energy store. Brief description of the drawings

The invention will be explained in more detail using an exemplary embodiment. Show in the accompanying drawings

Fig.l 'the basic structure of the oxygen generation and oxygen supply system according to the invention

Detailed description of the drawing

In Fig.l an oxygen generation and oxygen supply system is shown with a device 1 for generating a product gas highly enriched with oxygen, with a device 2 for breathing-dependent supply of the product gas to the patient 3 and with a measuring device 4 for detecting the breathing activity of the patient. The output of the measuring device 4 is coupled via the signal path 5 to a control input of the device 2.

A sensor 6, which is designed to detect the breathing phases of the patient 3, is applied to the patient 3. During the inhalation phase, a signal is generated by sensor 6 and output to measuring device 4 via signal path 7. The measuring device 4 contains, by way of example, a timer which, via the signal path 5 by means of the device 2, ensures that the device 2 outputs 9 product gas to the patient via the line 19 during the inhalation phase. This can be done, for example, by opening a two-way valve in the device 2 for a period of time which is determined by the duration of the signal. The measuring device 4 is equipped with an adjusting element 8 with which the ratio of the total duration of the inhalation phase to a period of the inhalation phase can be influenced during which the supply of the product gas to the patient 3 is to be provided. According to the saving principle, which has already been described in the explanation of the prior art, this period of time of supplying the product gas always begins approximately with the inhalation phase and extends only over the phase of inhalation which is most effective for oxygen. Depending on the preselection with the setting element 8, the supply stops before the end of the inhalation phase. Thus, on the one hand ensures that the patient is 3 sufficiently supplied with oxygen-rich breathing gas, on the other hand also use of the fact that only at the beginning of each breath the inhaled Sau ^¬ erstoff reaches the gas exchange in the lung, from which it follows that the oxygen namely sparingly but with sufficient effectiveness. The measuring device 4 also has an indication preselection switch 9 with which the patient can manually adjust the oxygen supply as a function of his or her load or demand. For example, three positions of the indication preselection switch 9 are possible: according to a supply quantity of product gas per breath adapted to the patient's resting phase, a supply quantity adapted to the normal load and a supply quantity appropriate to a high load. This can be achieved, for example, by increasing or decreasing the flow rate of product gas during the period in which the supply to the patient is released, depending on the setting of the indication preselection switch 9 via the signal path 5 in the device 2. This can be done, for example, by opening a valve in three stages.

In order to be able to ensure that only a quantity of product gas corresponding to the consumption or quantity to be supplied to the patient 3 is generated, the device 1 is designed in such a way that its performance with regard to the quantity of product gas generated in a unit time in normal operation corresponds to what is consumed by the average patient under normal load in the same time unit. In Fig. L it can be seen that the device 1 is exemplarily equipped with a compressor 1 0, two adsorption cylinders 1 1 and a surge tank 1 2. The compressor 1 0 is driven by an electric motor (not shown in the drawing) by a control power supply 1 3 is controlled and supplied with electrical energy via input 20. The compressor sucks in fresh air via input 21.

It is assumed that the normal output of the device 1 is approximately one liter of product gas per minute and the peak output is approximately two liters per minute. The compressor 1 0 is connected via a directional valve 1 5 through lines to each of the adsorption cylinders 1 1. In addition, the output of each adsorption cylinder is connected to the expansion tank 1 2 via lines. A connecting line 14 leads from the device 1 to the device 2, from which the product gas reaches the patient 3 via the line 19 according to the control by the measuring device 4.

In order to be able to make the oxygen generation and oxygen supply system handy and compact with regard to its geometrical dimensions, the measuring device 4 is linked to the control power supply 13 via an evaluation unit 16. For this purpose, as shown in Fig.l, the output signal from the measuring device 4 is not only present at the device 2, but also via the signal path 17 an input of the evaluation unit 16. This signal emanating from the measuring device 4 contains information about the duration of the supply of the product gas to the patient, corresponding to the period of the inhalation phase during which 3 product gas is supplied to the patient, and it contains information about the amount of the product gas supplied in accordance with the preselected position of the indication preselection switch 9. In the evaluation unit 1 6, two threshold switches are provided, of which a first, when the value falls below a lower setpoint, triggers the output of an increase signal and a second, when an upper setpoint is exceeded, triggers the output of a decrease signal. Three evaluation levels are therefore possible: normal consumption without an output signal at the threshold switches, consumption below normal consumption, signaled by the first threshold switch and increased consumption, signaled by the second threshold switch.

These evaluation levels correspond to three output signals of the evaluation unit 1 6, which are present at the control input of the control power supply 1 3 via the signal path 1 8. These three signal stages cause the power supply for the electric motor of the compressor 1 0 to be influenced via the control power supply 1 3 in such a way that, with normal consumption, the electric motor is controlled with the energy which is necessary for normal operation, i.e. to produce a product gas of about 1 liter per minute. When the control power supply 1 3 is actuated with the signal for lower consumption, the operating voltage for the electric motor of the compressor 1 0 is throttled, for example, as a result of which the production of the product gas drops to a value of approximately 0.5 to 0.7 liters per minute. In an analogous manner, the operating voltage for the compressor drive is increased and the production is increased to approximately 2 liters per minute with increased consumption.

In this way, the amount of product gas produced is at least approximately adapted to the patient's consumption. This results in the essential advantage that the device 1 for generating the product gas can be designed in an optimized dimension, because because of the coupling of consumption determination on the patient 3 and product gas generation, the quantity of product gas produced is influenced directly and as a result space-consuming buffers or storage for the product gas can be dispensed with. So no excess production is necessary to store product gas. The function of the expansion tank 1 2 is reduced to the compensation of pressure fluctuations within certain limits, whereby its size can be minimized. Because of the lower mass and the reduced volume of the assemblies of the oxygen generation and oxygen supply system, it is advantageously possible to accommodate them in a common housing, for example in the form of a hand case.

The interaction of device 1, device 2, the measuring device 4 and the evaluation unit 1 6 and their respective equipment are shown in this embodiment of the invention for the sake of clarity in the simplest way. Sufficiently good results can already be achieved with these simple means, which ensure that the oxygen generation and oxygen supply system can be manufactured sufficiently small and compact and thus guarantee the ease of handling and significantly improved mobility of the patient, but it is possible to achieve an even clearer result through improved structural designs. However, a higher outlay in technical measurement and control technology does not result in a linearly saved device volume and lower power consumption, so that the outlay and the benefits have to be weighed up against one another.

So it is e.g. conceivable to track the flow rates of product gas to the patient 3 and thus the actual consumption of product gas with suitable transducers. This constantly updating consumption signal could be used as the basis for a control loop in which the supply quantity is automatically adjusted according to the indication. In addition, this consumption signal could be used in a correspondingly further developed evaluation unit 1 6 for the infinitely variable regulation of the control power supply 1 3, so that instead of the three production stages assumed in the example, which are adapted to a reduced demand, a normal demand and an increased demand, a further optimization when adjusting the Produced amount of product gas to the amount consumed achievable and thereby a further reduction in size. and a further reduction in the power consumption of the oxygen generation and oxygen supply system is possible.

Claims

 Expectations J_. Combined oxygen generation and oxygen supply system, in particular for long-term human medical oxygen therapy in the patient's home environment, with a device (1) for generating a product gas that is highly enriched with oxygen, with a device (2) for supplying the product gas to the patient in a dose-dependent manner ( 3) and with a measuring device (4) for detecting the breathing activity of the patient (3), the Output of the measuring device (4) is coupled to a control input of the device (2) for supplying the product gas to the patient, characterized in that the output of the measuring device (4) is branched to record breathing activity and at least one of the branches at the input of an evaluation circuit device (1 6) for the current consumption of the product gas is present, that the signal output of this evaluation circuit (1 6) is applied to a signal input of a control circuit for the device (1) for generating the product gas, that the performance of the device (1) for generating the Product gas is dimensioned so that that generated during normal operation in one unit of time Amount of product gas approximately corresponds to the amount required by an average patient in the same time unit and that the signal output by the evaluation circuit (1 6) is provided for influencing the amount of product gas generated per unit time via the control circuit. 2. Combined oxygen generation and .Oxygen supply system according to claim 1, characterized in that in the device (1) for generating the product gas, a compressor (1 0), an electric motor as a drive unit for the compressor and a control power supply (1 3) is provided and the Output of the evaluation circuit (1 6) is linked to the control power supply (1 3). 3. Combined oxygen generation and oxygen supply system according to one of the preceding claims, characterized in that two threshold switches are provided in the evaluation circuit (1 6), a first of which at If a lower setpoint is undershot, the output of an increase signal and a second if an upper setpoint is exceeded, the output of a decrease signal, in each case based on the amount used in normal operation of the product gas, to the control circuit for the device (1) for producing the product gas. 4. Combined oxygen generation and oxygen supply system according to one of the preceding claims, characterized in that in the device (1) for generating the product gas in addition to the compressor (1 0) two adsorption cylinders (1 1) and an expansion tank (1 2) are provided and over Lines are interconnected, the output of the compressor (1 0) being connected via a directional valve to each of the adsorption cylinders (1 1) and each of the adsorption cylinders (1 1) via a further directional valve to the expansion tank (1 2). 5. Combined oxygen generation and oxygen supply system according to one of the preceding claims, characterized in that the device (1) is designed for generating the product gas with a normal output of 0.5 to 1 liter per minute and a peak output of 1 to 2 liters per minute . 6. Combined oxygen generation and oxygen supply system according to one of the preceding claims, characterized in that all modules are housed together in a transportable housing, with manually operated switching elements and visually controllable monitoring elements being provided on the outside of the housing. 7. Combined oxygen generation and oxygen supply system according to claim 6, characterized in that the transportable housing is designed as a suitcase consisting of hard shells.