PNEUMATIC MODULE AND PROCESS FOR SUPPLYING A CONSUMER WITH A PRESSURE SURGE-FREE STREAM OF MEDICAL GASES OR MEDICAL AIR

Abstract

A pneumatic module (1) and a process supply a patient with breathing gas. An inlet (2) connects a medical gas source and an outlet (3) via a main flow duct (4) with a flow valve (5), setting a downstream volume flow, and a pressure relief valve (6) downstream of the flow valve (5) that vents the main flow duct (4) when a pressure is exceeded. A control duct (7), connected to a relief valve control port (8), branches off from the main flow duct (4) at a branch (15) upstream of the flow valve (5). A pressure control unit (9), arranged in the control duct, sets a flow value through the control duct (7), and acts on the control port (8) for setting a maximum pressure. The control port (8) is connected to a compensating element (10) providing a compensating volume (11) for the control duct (7).

Claims

1. A pneumatic module for supplying a patient with breathing gas, the pneumatic module comprising: an inlet for connecting a gas source for providing a medical gas and/or medical air; an outlet for connecting a hose line leading to the patient; a main flow duct from the inlet to the outlet; a flow valve connected to the main flow duct and configured to set a volume flow of a breathing gas stream flowing downstream of the flow valve; a pressure relief valve pneumatically connected to the main flow duct downstream of the flow valve and configured to vent the main flow duct upon a pressure in the main flow duct exceeding a permissible maximum pressure, the pressure relief valve having a control port; a control duct connected to the control port and branching off from the main flow duct at a branch upstream of the flow valve; a pressure control unit connected to the control duct and configured to set a flow value, indicative of a control flow, which flows through the control duct and which acts on the control port, for setting the permissible maximum pressure; and a compensating element configured to provide a compensating volume for the control duct, wherein the control port is connected to the compensating element.

2. A pneumatic module in accordance with claim 1, wherein the compensating element comprises an elastically deformable element at least indirectly functionally connected with the control port.

3. A pneumatic module in accordance with claim 2, wherein the elastically deformable element comprises an elastic expansion bellows.

4. A pneumatic module in accordance with claim 1, wherein the control duct comprises an outlet downstream of the pressure control unit, via which the control flow can be released into a surrounding area under an atmospheric pressure prevailing in the surrounding area.

5. A pneumatic module in accordance with claim 1, wherein the pressure control unit comprises a flow valve configured to set a volume flow of the control flow flowing downstream of the flow valve.

6. A pneumatic module in accordance with claim 1, wherein the pressure control unit comprises a flow resistance element arranged in the control duct, wherein the flow resistance element has a constant flow resistance or an adjustable flow resistance.

7. A pneumatic module in accordance with claim 1, wherein the pressure control unit comprises: a flow valve, at which a volume flow of the control flow flowing downstream of the flow valve can be set; and a flow resistance element arranged in the control duct, wherein the flow resistance element has a constant flow resistance or an adjustable flow resistance.

8. A ventilation system for supplying a patient with a breathing gas, the ventilation system comprising: a ventilator comprising a compressor for providing an air and/or gas stream at a ventilator outlet; a hose system configured to feed the air and/or gas stream at least partially to a patient; and a pneumatic module comprising: a module inlet connected at least indirectly to the ventilator outlet: a module outlet connected to a hose system inlet of the hose system; a main flow duct from the module inlet to the module outlet; a flow valve connected to the main flow duct and configured to set a volume flow of a breathing gas stream flowing downstream of the flow valve; a pressure relief valve pneumatically connected to the main flow duct downstream of the flow valve and configured to vent the main flow duct upon a pressure in the main flow duct exceeding a permissible maximum pressure, the pressure relief valve having a control port; a control duct connected to the control port and branching off from the main flow duct at a branch upstream of the flow valve; a pressure control unit connected to the control duct and configured to set a flow value, indicative of a control flow, which flows through the control duct and which acts on the control port, for setting the permissible maximum pressure; and a compensating element configured to provide a compensating volume for the control duct, wherein the control port is connected to the compensating element.

9. A ventilation system in accordance with claim 8, wherein the compensating element comprises an elastically deformable element at least indirectly functionally connected with the control port.

10. A ventilation system in accordance with claim 9, wherein the elastically deformable element comprises an elastic expansion bellows.

11. A ventilation system in accordance with claim 8, wherein the control duct comprises an outlet downstream of the pressure control unit, via which the control flow can be released into a surrounding area under an atmospheric pressure prevailing in the surrounding area.

12. A ventilation system in accordance with claim 8, wherein the pressure control unit comprises a flow valve configured to set a volume flow of the control flow flowing downstream of the flow valve.

13. A ventilation system in accordance with claim 8, wherein the pressure control unit comprises a flow resistance element arranged in the control duct, wherein the flow resistance element has a constant flow resistance or an adjustable flow resistance.

14. A ventilation system in accordance with claim 8, wherein the pressure control unit comprises: a flow valve, at which a volume flow of the control flow flowing downstream of the flow valve can be set; and a flow resistance element arranged in the control duct, wherein the flow resistance element has a constant flow resistance or an adjustable flow resistance.

15. A process for supplying a consumer with a pressure surge-free stream of a medical gas and/or medical air, the process comprising the steps of: providing a stream of a medical gas and/or medical air into a main flow duct at an inlet of the main flow duct; sending a first part of the stream of a medical gas and/or medical air in the main flow duct to a flow valve, via which a volume flow of a breathing gas stream flowing downstream of the flow valve is set; venting the main flow duct by means of a pressure relief valve upon a permissible maximum pressure being exceeded; and branching off a second part of the provided stream of a medical gas and/or medical air into a control duct upstream of the flow valve and sending the second part of the provided stream of a medical gas and/or medical air in the control duct to a pressure control unit configured to set a flow value indicative of a control flow, which flows through the control duct and acts on a control port of the pressure relief valve for setting the permissible maximum pressure compensating or absorbing pressure surges and air and/or gas volumes displaced thereby, which occur at the control port of the pressure relief valve, in a compensating volume, which is generated by an at least partially elastic deformation of a compensating element, which compensating element is operatively connected to the control port.

16. A process in accordance with claim 15, wherein the control flow is released from the control duct via an outlet into a surrounding area under an atmospheric pressure prevailing in the surrounding area.

17. A process in accordance with claim 15, wherein a volume flow of the control flow flowing through the control duct and acting on the control port of the pressure relief valve is set in the pressure control unit as a function of the permissible maximum pressure desired in the main flow duct.

18. A process in accordance with claim 15, wherein at least one flow resistance element, having a flow resistance that is maintained at a constant value or having a changeable flow resistance, is arranged in the control duct.

19. A process in accordance with claim 15, wherein a flow resistance of the control duct is changed as a function of the permissible maximum pressure desired for the main flow duct.

20. A process in accordance with claim 15, wherein a pressure surge-free stream of a gas and/or medical air is fed to a laboratory apparatus and/or to a medical device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the drawings:

[0032] FIG. 1 is a graph showing a pressure curve (pressure course) during a ventilation cycle;

[0033] FIG. 2 is a graph showing a view of an overshooting of the pressure curve during the inhalation phase of a ventilation cycle;

[0034] FIG. 3 is a pneumatic circuit diagram of a first variant of a pneumatic module configured according to the present invention with a compensating element according to a first embodiment;

[0035] FIG. 4 is a pneumatic circuit diagram of a first variant of a pneumatic module configured according to the present invention with a compensating element according to a second embodiment;

[0036] FIG. 5 is a pneumatic circuit diagram of a second variant of a pneumatic module configured according to the present invention with a compensating element according to the first embodiment;

[0037] FIG. 6 is a schematic detail view of an expansion bellows, which can be used for a pneumatic module configured according to the present invention; and

[0038] FIG. 7 is a schematic view showing a ventilation system for supplying a patient with a breathing gas.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] Referring to the drawings, FIG. 1 shows the pressure curve during a ventilation cycle of a ventilated patient. Such a ventilation may be carried out, for example, with an open care or resuscitation unit for newborn infants, which is carried out above all when the breathing of the newborn infant does not begin spontaneously immediately after birth.

[0040] The ventilator of the care unit is connected via a hose system to a patient connection piece, especially a breathing mask, which is pressed over the mouth and the nose of the patient. To carry out the ventilation, the desired pressure difference is set by an operator, and the frequency for the recurrence of the ventilation cycles can be set as well.

[0041] As is shown in FIG. 1, the pressure difference is between a lower pressure, conventionally called PEEP (positive end-expiratory pressure) in ventilation, as well as an upper pressure, usually called PIP (positive inspiratory pressure). The PEEP is the pressure that becomes established at the end of the exhalation, whereas the PIP is reached at the end of the inhalation. FIG. 1 shows the pressure curve for a complete ventilation cycle, in which the two pressure levels PEEP and PIP are marked.

[0042] The breathing gas stream is delivered by the ventilator independently from the current phase of the ventilation cycle. An exhalation valve, through which air exhaled by the patient can escape, is closed at the beginning of the inhalation, so that the lungs of the patient will be filled with the breathing gas stream being delivered by the ventilator, until the PIP is reached. When this pressure level is reached, the main flow duct leading to the patient is ventilated, as it will be explained in even more detail below, so that the PIP, which is in this case the maximum pressure predefined by the operator in the main flow duct, in the hose system connected thereto and in the lungs of the patient, is maintained at a constant value until the exhalation of the breathing gas contained in the lungs takes place via the exhalation valve.

[0043] In addition to the view according to FIG. 1, FIG. 2 shows a view of a ventilation cycle, in the course of which an unintended overshooting of the pressure occurs, which leads to an overshooting of the maximum pressure set by the operator, here the PIP. According to the exemplary embodiment shown in FIG. 2, a PEEP of 5 mbar and a PIP of 20 mbar were set. Shortly after reaching the PIP, which should not ideally be exceeded, there is an increase in the pressure in the main flow duct to a value of 24 mbar and hence to the set maximum pressure being exceeded by 20% relative to the desired pressure difference. The development of pressure surges during the supply of a stream of medical gas and/or medical air is prevented by the use of a pneumatic module configured according to the present invention as well as of a corresponding process.

[0044] FIG. 3 shows a pneumatic circuit diagram of a pneumatic module 1 configured according to the present invention. The pneumatic module 1 is supplied with a stream of medical gas and/or medical air from a gas or air source. Such a gas or air source may be both a compressor of a ventilator 20 or anesthesia apparatus, a pressurized gas cylinder or a central hospital supply system for medical gases and medical air. FIG. 7 shows the ventilator 20 with the compressor 22.

[0045] A stream of medical gas and/or medical air, which will hereinafter be called breathing gas stream in a simplified manner, flows via an inlet 2 into a main flow duct 4 of the pneumatic module 1. A flow valve 5, at which the desired volume flow of the breathing gas stream can be set by an operator, is arranged first in the main flow duct 4. The breathing gas stream flows with the constant volume flow through the main flow duct 4, which is usually a part of a hose system 24 or is connected to this hose system 24, to the patient connection piece, for example, to a breathing mask, which is pressed over the mouth sand the nose of the patient.

[0046] The breathing gas stream flows steadily through the main flow duct 4 independently from the current phase of the ventilation cycle. If the patient is inhaling, the outlet is closed at an exhalation valve, not shown here, via which the patient can exhale, so that the breathing gas stream completely enters the lungs of the patient being ventilated. The lungs will fill during this phase of the ventilation cycle until the maximum pressure of the PIP set by the operator is reached. If this pressure level is reached, the main flow duct 4 is vented via the pressure relief valve 6 connected pneumatically to the main flow duct 4. It is ensured in this manner that the pressure in the main flow duct 4 and hence at the patient will not rise above the maximum pressure set by the operator, the PIP.

[0047] In order to make it possible to set the maximum pressure prevailing in the main flow duct 4, here the PIP, as needed, a control is provided, which will be explained in more detail below.

[0048] A control duct 7 branches off from the main flow duct 4 at a branch 15 upstream of the flow valve 5, and a pressure control unit 9, with which a control pressure within the control duct 7, especially at the control port 8 of the pressure relief valve 6, can be set in a specific manner, is located downstream of this branch 15. According to the configuration space shown in FIG. 3, the pressure control unit 9 has a flow valve 12, with which the operator can set a control flow, here a control air flow, in a specific manner with a constant volume flow, as well as two flow resistance elements 13a, 13b with suitably selected flow resistance. The control flow flows during the operation of the pneumatic module 1 through an outlet 14 out of the control duct 7 into the surrounding air and hence against the ambient or atmospheric pressure prevailing in the surrounding area.

[0049] In terms of the technical configuration and its functionality, the flow valve 12 arranged in the control duct 7 corresponds to the flow valve 5 arranged in the main flow duct 4, but the volume flow of the control flow is markedly lower than that of the breathing gas stream in the main flow duct 4. The ratio of the volume flows of the control flow to the breathing gas flow is usually 1:10 in the exemplary embodiment being explained here.

[0050] In the flow direction between the flow valve 12 and the outlet 14, the pressure control unit 9 has two flow resistances 13a, 13b arranged in the control duct 7. By a suitable selection, alternatively setting of the flow resistances 13a, 13b, it is possible to set in a specific manner a control pressure, which prevails within the control duct 7 and acts on the control port 8 of the pressure relief valve 6 while setting at the same time a defined volume flow for the control flow.

[0051] According to the embodiment shown in FIG. 3, the pressure relief valve 6 is a diaphragm valve, where the diaphragm 16 pneumatically separates the main flow duct 4 from the control duct 7. A movement of the diaphragm 16 therefore takes place as a function of the pressures present on both sides, i.e., the pressure in the main flow duct 4 as well as the control pressure. If the pressure in the main flow duct 4 exceeds the control pressure and hence the maximum pressure desired by the operator, here the PIP, the diaphragm is deflected such that the main flow duct 4 is vented via a ventilation opening 17 of the pressure relief valve 6 as long as this operating state persists, so that the pressure in the main flow duct 4 remains constant.

[0052] If the operator increases, for example, the volume flow of the control flow, the control pressure rises within the control duct 7 and so does the maximum pressure predefined for the main flow duct 4. The operator can set in this manner the control pressure and hence the predefined maximum pressure, here the PIP, in a continuously adjustable manner.

[0053] As soon as the pressure prevailing in the main flow duct 4 exceeds the maximum pressure preset by the operator, a movement of the diaphragm 16 of the pressure relief valve 6 takes place, as was described before, in the direction of the control duct 7. Based on this movement, a gas or air volume in the area of the control port 8 in the control duct 7 must be displaced corresponding to the movement of the diaphragm 16. Without the compensating element 10 provided according to the present invention, which provides a compensating volume 11 connected pneumatically to the control port 8, the gas or air volume additionally displaced in the control duct 7 by the diaphragm 16 would have to be released via the outlet 14 of the control duct 7 into the surrounding area against the existing flow resistances and the prevailing atmospheric pressure. Due to the existing flow resistances, especially the second flow resistance element 13b arranged between the control port and the outlet, an increase in the control pressure in the control duct 7, which increase acts, in turn, on the control port 8 and on the diaphragm 16 of the pressure relief valve 6, is fed back into the main flow duct 4. This feedback would ultimately lead again to an increase in the pressure in the main flow duct 4 above the maximum pressure preset by the operator, i.e., the PIP.

[0054] In order reliably to prevent such an unintended increase in the pressure in the main flow duct 4 above the maximum pressure set, a compensating element 10 with an elastic wall, by which a compensating volume connected pneumatically to the control port 8 is made available as needed, is provided in the control duct 7. The flow resistance between the control port 8 of the pressure relief valve 6 and the compensating element 10 is configured here to be so small that when the set maximum pressure is reached in the main flow duct 4, the air volume additionally displaced on the actuation side of the pressure relief valve 6 can be absorbed directly and rapidly by the compensating volume 11 and it does not have to be removed via the outlet 14 of the control duct 7 into the surrounding area. Based on this technical measure, an overshooting of the pressure in the main flow duct 4 above the set maximum pressure is reliably and rapidly prevented from occurring.

[0055] An essential advantage of the solution according to the present invention over a likewise conceivable solution, which provides for a reduction, at least from time to time, of the flow resistances present between the control port 8 of the pressure relief valve 6 and the outlet 14 in the flow duct 7, especially of the flow resistance of the second flow resistance element 13b, is that the volume flow of the control flow would be greater in this alternative solution during the normal operation at equal control pressure, which would, on the whole, increase the consumption of medical gas and/or medical air. The technical solution according to the present invention can thus be implemented in a technically comparatively simple manner and it also represents an economically meaningful solution.

[0056] It is essential for the configuration of the compensating element 10 for providing from time to time a compensating volume 11 in the control duct 7 that this is, on the other hand, so elastic that a gas or air volume additionally displaced in the control duct 7 can be absorbed rapidly and completely, and, on the other hand, it is not so elastic that the filling of the control duct 7 and the reaching of the desired control pressure at the start-up of the pneumatic module 1 would last too long not to be ready for use rapidly in an emergency. The compliance of the compensating element 10, which is a value indicative of an increase in volume as a function of a pressure increase acting from the inside, is configured therefore such that the above-described boundary conditions are taken into account.

[0057] The compensating element 10 is configured as an expansion bellows made of silicone in the embodiment described in connection with FIG. 3, wherein the folds have a uniform configuration and are arranged symmetrically in relation to a central axis of the expansion bellows. This compensating element 10 is suitable for operation in a pneumatic module 1, which can also be used in emergencies. The compliance of the expansion bellows is selected here to be such that the displaced volume developing in certain cases of operation in the control duct 7 can be absorbed rapidly and completely, and rapid filling of the compensating volume 11 provided additionally is ensured when the pneumatic module 1 is put into operation.

[0058] FIG. 4 shows a pneumatic circuit diagram of a special embodiment of a pneumatic module 1, which is configured according to the present invention and which thus likewise has an additional compensating element 10, which provides a compensating volume 11 for the control duct 7 as needed. The pneumatic configuration of the pneumatic module 1 corresponds here to that which was described in connection with FIG. 3. Contrary to the pneumatic module 1 according to FIG. 3, the compensating element 10 is not, however, configured in the form of an elastic balloon with a flat balloon wall. It is conceivable in this case to likewise use silicone or a suitable rubber material for the compensating element 10. It is essential again that the compliance of the compensating element 10 is selected to be such that a rapid and immediate absorption of the displaced volume developing in the control duct 7 in certain operating situations is ensured, on the one hand, and full readiness to operate is established as rapidly as possible when putting the pneumatic module 1 into operation, on the other hand.

[0059] The pneumatic module 1, whose pneumatic circuit diagram is shown in FIG. 5, differs from the pneumatic modules 1 described before by an alternatively configured pressure control unit 9 in the control duct 7. According to the exemplary embodiment shown in FIG. 5, the pressure control unit 9 has a flow resistance element 13 with a constant, alternatively variable flow resistance and a flow valve 12, which is arranged downstream of the flow resistance element 13 in front of the outlet 14 of the control duct 7, via which an operator can set a volume flow of the control flow.

[0060] Depending on the volume flow upstream of the flow resistance element 13 and of the flow resistance of the flow resistance element 13, a control flow with constant volume flow becomes established upstream of the flow valve 12. By actuating the flow valve 12, this volume flow and at the same time the control pressure prevailing within the flow duct 7 can be changed. The control pressure set by the operator in this manner is present, in turn, at the control port 8 of the pressure relief valve 6, so that the maximum pressure, here the PIP, can be set in the main flow duct 4 by setting the flow valve 12 in a suitable manner.

[0061] A compensating element 10, in the form of an expansion bellows according to the embodiment described, which is pneumatically connected to the control port 8 of the pressure relief valve 6, is provided in turn according to the present invention. The compensating volume 10 is dimensioned such that when necessary, especially when the permissible maximum pressure is reached or exceeded in the main flow duct 4, i.e., when the main flow duct 4 is vented via the pressure relief valve 6, it can rapidly and fully absorb the gas or air volume displaced additionally in the area of the control port 8 in the control duct 7.

[0062] FIG. 6 shows a specially configured elastic compensating element 10, which can provide in its interior a compensating volume 10 at least from time to time based on an expansion of its outer wall. A gas or air volume displaced additionally in the control duct 7 over a short time period is absorbed according to the present invention in the compensating volume 11 of the compensating element 10 in certain operating situations.

[0063] The compensating element 10 shown is configured as an expansion bellows made of silicone. The compensating element 10 has a port 18 in the upper area in order to connect this compensating element pneumatically at least indirectly to the control port 8 of a pressure relief valve 6. Furthermore, the compensating element 10, here the expansion bellows, has a plurality of folds 19, three folds in this case, which have all a uniform configuration and are arranged symmetrically in relation to a central axis of the expansion bellows. The expansion bellows shown makes possible a rapid and complete absorption of the gas or air volume displaced additionally in certain operating situations in a control duct 7 of a pneumatic module 1 configured according to the present invention. The compliance of the expansion bellows, i.e., the ratio of the volume enlargement to the pressure increase, is selected to be such that the gas or air volume displaced additionally can be absorbed rapidly and completely, on the one hand, and, on the other hand, that filling of the compensating element 10 takes place so rapidly when a pneumatic module 1 is put into operation that a pneumatic module 1 configured according to the present invention can be used for emergency ventilation.

[0064] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

[0065] 1 Pneumatic module [0066] 2 Inlet [0067] 3 Outlet [0068] 4 Main flow duct [0069] 5 Flow valve [0070] 6 Pressure relief valve [0071] 7 Control duct [0072] 8 Control port [0073] 9 Pressure control unit [0074] 10 Compensating element [0075] 11 Compensating volume [0076] 12 Flow valve in the control duct [0077] 13 Flow resistance element [0078] 13a First flow resistance element [0079] 13b Second flow resistance element [0080] 14 Outlet of the control duct [0081] 15 Branch [0082] 16 Diaphragm [0083] 17 Ventilation opening [0084] 18 Port of the compensating element [0085] 19 Fold [0086] 20 Ventilator [0087] 22 Compressor [0088] 24 Hose system