Patent Application
20230211108
This application claims the benefit of priority under 35 U.S.C. § 119 of German Application 10 2022 100 254.3, filed Jan. 6, 2022, the entire contents of which are incorporated herein by reference.
The present invention pertains to a device and to a process for connecting a patient-side coupling unit to a source and/or to a sink for a gas. The gas comprises oxygen. The patient-side coupling unit is at least temporarily connected or can be connected to a patient.
The device according to the present invention and the process according to the present invention can be used to ventilate the patient artificially. The patient-side coupling unit is arranged in or at or on the body of the patient. The gas flows from at least one source through an inhalation duct to the patient-side coupling unit. Exhaled gas flows away from the patient-side coupling unit through an exhalation duct.
It is desired to control by closed-loop control or at least by open-loop control the volume flow through the inhalation duct and/or through the exhalation duct to or from the patient-side coupling unit and/or the pressure in the inhalation duct and/or in the exhalation duct. The control gain of the control is to have the actual time course of the volume flow and/or the pressure to follow a predefined desired time course. The present invention is used in this application in the inhalation duct and/or in the exhalation duct.
A basic object of the present invention is to provide a connection device and a process for connecting a patient-side coupling unit to a source and/or to a sink for a gas, wherein the gas flows from the source through an inhalation duct to the patient-side coupling unit and/or through an exhalation duct away from the patient-side coupling unit to the sink and wherein the actual time course of a volume flow or of a pressure can better be controlled than in prior-art connection devices and processes.
The present invention is accomplished by a connection device having features according to the invention and by a connection process having features according to the invention. Advantageous embodiments are described herein. Advantageous embodiments of the connection device are, insofar as meaningful, also advantages of the connection process according to the present invention and vice versa.
The connection device according to the present invention is capable of connecting a patient-side coupling unit to a source or to a sink for a gas. This gas preferably comprises oxygen and/or air. The gas optionally comprises, in addition, at least one anesthetic agent (anesthetic). The gas may also be air exhaled by the patient and may additionally comprise carbon dioxide. An embodiment of the connection device according to the present invention is optionally capable of connecting the patient-side coupling unit both to the source and to the sink. It is possible that the same medical device acts both as a source and as a sink. The gas can also be a component of a gas mixture wherein the gas mixture is conveyed to the patient-side coupling unit or is discharged away from the patient-side coupling unit. The source is a supplying connector for supplying the gas component or a medical device or the patient-side coupling unit, e.g. The source can also be a mixing point in which the gas mixture is created or develops. The sink is a stationary or mobile receptacle for a gas, in particular for a gas comprising an anesthetic, or in the case of a breathing circuit the medical device, e.g.
The patient-side coupling unit is at least temporarily connected or can be connected to a patient. In particular, the patient-side coupling unit is arranged in or at or on the body of the patient.
The connection device according to the present invention comprises a valve device and two fluid guide units, namely a source-side fluid guide unit and a patient-side fluid guide unit. A “fluid guide unit” is defined as a component that is capable of guiding a fluid along a trajectory and ideally completely prevents the fluid from leaving this trajectory. A rigid tube and a flexible hose are two examples of a fluid guide unit. The fluid guide unit may be a two-lumen hose.
The source-side fluid guide unit establishes at least temporarily a fluid connection between the source or the sink for the gas and the valve device or is capable of establishing such a fluid connection. The patient-side fluid guide unit establishes at least temporarily a fluid connection between the patient-side coupling unit and the valve device or is capable of establishing such a fluid connection. The two fluid guide units are preferably connected in series via the valve device.
The gas flows in a flow direction from the source to the patient-side coupling unit or from the patient-side coupling unit to the sink. The terms “upstream” and “downstream” are related to this flow direction. The one fluid guide unit is arranged upstream, and the other fluid guide unit is arranged downstream of the valve device. Whether the source-side fluid guide unit or the patient-side fluid guide unit is the fluid guide unit arranged upstream depends on the flow direction and hence on the use of the present invention.
The connection device according to the present invention comprises, furthermore, the valve device. This valve device comprises a first valve and at least one second valve, and optionally a plurality of second valves (one or more additional valves). A “valve” is defined as a component through which a fluid can flow, wherein the component is capable of changing and, as a rule, especially completely prevent the volume flow of the fluid through the valve within a construction-related range. The valve may change the volume flow in increments or continuously. The “volume flow” is an indicator of the volume per unit of time of the fluid, which flows through the valve or through a fluid guide unit.
The second valve or at least one second valve of the valve device is connected in parallel to the first valve. During the flow from the fluid guide unit arranged upstream to the fluid guide unit arranged downstream, the gas flows through at least one valve of the valve device, i.e., through the first valve and/or through the second valve and/or through at least one second valve. It is possible that the gas flows only through one valve at a given time because the other valve is closed. It is also possible that the gas flows at a given time simultaneously through both valves or through at least two valves connected in parallel.
A signal-processing control unit of the connection device according to the present invention is capable of automatically setting a respective control pressure at each valve of the valve device. The control pressures at the valves may differ from one another. The setting of the control pressure at a valve causes the volume flow through this valve to be set at a defined value. In addition, the setting of the control pressure affects the pressure in the fluid guide unit arranged downstream.
Due to the control unit setting a respective control pressure automatically at each valve of the valve device, the control unit is capable of automatically controlling the volume flow through and/or the pressure in the fluid guide unit arranged downstream. The control gain of the setting of the control pressure is to have the time course of the actual volume flow through the fluid guide unit arranged downstream or the pressure in this fluid guide unit to follow a predefined time course.
The connection process according to the present invention is carried out automatically with the use of a connection device according to the present invention. The gas flows from the source to the patient-side coupling unit or from the patient-side coupling unit to the sink. The volume flow through the fluid guide unit arranged downstream or the pressure in the fluid guide unit arranged downstream is controlled by closed-loop control or open-loop control. As a result, the time course of the actual volume flow or of the pressure follows a predefined time course. The step of controlling the volume flow or the pressure comprises the step of setting and optionally changing a respective control pressure at least once at the first valve and/or at the second valve or at the at least one second valve. It is also possible that both the volume flow and the pressure are controlled.
The inventors determined in internal experiments that the volume flow or the pressure can be controlled more easily when the gas can flow through two valves connected in parallel, compared to an embodiment in which the gas only flows through one valve. The present invention makes it possible to control the volume flow or the pressure in the fluid guide unit arranged downstream relatively reliably, even if the volume flow and/or the pressure in the fluid guide unit arranged upstream is subject to great variations over time or may at least vary greatly.
In many cases, the present invention eliminates the need to switch the valve device over abruptly from one state to another state. Rather, it is possible to continuously or smoothly reduce the volume flow through the one valve of the valve device and also to continuously or smoothly increase the volume flow through the other valve in an overlapping manner over time. As a result, the risk of an oscillation of the volume flow and/or of the pressure in an undesired extent is reduced thereby.
At least two valves of the valve device according to the present invention are connected in parallel and both are arranged between the two fluid guide units.
In one application, the connection device according to the present invention connects the patient-side coupling unit to a source for the gas. The source is, for example, a stationary supply port for the gas or it comprises at least one cylinder or other receptacle containing the gas or a fluid guide unit for the gas. It is also possible that the source is a mixing point, at which the gas being a gas mixture is obtained by mixing the gas from at least two gas components. The source may also be a ventilator, which carries out a sequence of ventilation strokes and feeds a respective quantity of a gas into the source-side fluid guide unit during each ventilation stroke. The present invention is used in these applications in an inhalation (inspiration) duct, which leads from the source to the patient-side coupling unit and in which the gas is delivered to the patient-side coupling unit. The connection device is arranged in the inhalation duct in this application. The source-side fluid guide unit is the fluid guide unit arranged upstream and the patient-side fluid guide unit is the fluid guide unit arranged downstream.
In another application, the connection device according to the present invention connects the patient-side coupling unit to a sink for the gas. The sink is, for example, the surrounding area or a stationary fluid receptacle. The source-side fluid guide unit is the fluid guide unit arranged downstream, and the patient-side fluid guide unit is the fluid guide unit arranged upstream.
It is also possible that a closed circuit, for example, a closed ventilation circuit for the artificial ventilation of a patient, is established between the patient-side coupling unit and a medical device. The medical device, e.g. an anesthesia apparatus, acts both as a source and as a sink in this embodiment. A fluid conveying unit maintains a flow of gas in the ventilation circuit. The sink is, for example, the fluid conveying unit in this application, and the gas flows from the patient-side coupling unit to this sink, i.e., to the fluid conveying unit. The present invention is used in these applications in an exhalation (expiration) duct, which leads from the patient-side coupling unit to the sink and to which the connection device belongs.
It is also possible to use the present invention both in an inhalation duct and in an exhalation duct, i.e., twice. An example of such a dual application is a ventilation circuit, in which a fluid conveying unit maintains a flow of gas, wherein a gas is delivered through the inhalation duct to the patient-side coupling unit and exhaled gas flows from the patient-side coupling unit through the exhalation duct.
According to a preferred embodiment, a respective pre-pressure (admission pressure) is present at each valve of the valve device. The pre-pressure present at the valve depends on the pressure in the fluid guide unit arranged upstream. Especially preferred is the pre-pressure that is present at the valve being equal to the pressure in the fluid guide unit arranged upstream. The volume flow through the fluid guide unit arranged downstream depends on both the pre-pressure that is present at the valve and on the control pressure that is set at the valve by the control unit.
In a preferred embodiment, each valve of the valve device comprises a respective valve body and a valve body seat. On its way from the fluid guide unit arranged upstream to the fluid guide unit arranged downstream, the gas is capable of flowing through the valve body seat. Each valve body seat has a respective construction-related cross-sectional area. The valve body can move relative to the valve body seat. The position of the valve body relative to the valve body seat determines the effective cross-sectional area that is available for the gas for flowing through this valve. The effective cross-sectional area is smaller than or equal to the construction-related maximal cross-sectional area.
Preferably the control pressure present at the valve acts on the valve body and aims to press the valve body against the valve body seat. The control pressure therefore determines the force with which the valve body is pressed against the valve body seat. Preferably the pre-pressure aims at moving the valve body away from the valve body seat.
According to an implementation of this preferred embodiment, the construction-related cross-sectional area of one valve body seat is smaller than the cross-sectional area of the other or at least one other valve body seat. It is, however, also possible that both or at least two valve body seats have the same construction-related cross-sectional area, and all valve body seats optionally have the same construction-related cross-sectional area. Preferably, the control unit of the connection device according to the present invention causes the gas to flow exclusively through the valve with the smaller cross-sectional area in case of a volume flow below a first threshold and to flow exclusively through the valve with the larger cross-sectional area in case of a volume flow above a second threshold, wherein the second threshold is higher than the first threshold or is equal to the first threshold.
In one embodiment, a controllable fluid conveying unit is associated with at least one valve of the valve device. This fluid conveying unit is or comprises especially a pump or a blower or a piston-cylinder unit. It is possible that a separate respective controllable conveying guide unit is associated with each valve. It is also possible that the same controllable fluid conveying unit is associated with two different valves of the valve device.
The fluid conveying unit or each fluid conveying unit is capable of setting and changing the control pressure, which is present at the associated valve or at each associated valve. The signal-processing control unit (control device) of the connection device is capable of controlling the fluid conveying unit with the subordinate control gain that the fluid conveying unit sets the control pressure at the associated valve. The control pressure set—more precisely, a desired value for the control pressure to be set—depends on the measured volume flow to the valves connected in parallel. The control unit receives measured values from a sensor, which measures an indicator of the volume flow upstream of the valve device, and it calculates the desired value for the control pressure to be set by the fluid conveying unit.
This embodiment makes it possible to compensate for the inevitable influence of the volume flow on the back pressure, i.e., on the pressure downstream of the valve, to a certain degree.
Each valve of the valve device preferably has three coupling points, namely, a pre-pressure-side coupling point, a back pressure-side coupling point, and a control pressure-side coupling point. The pre-pressure-side coupling point is in a fluid connection with the fluid guide unit arranged upstream. Thus, a pre-pressure is present at the pre-pressure-side coupling point. The back pressure-side coupling point is in a fluid connection with the fluid guide unit arranged downstream. A back pressure is thus generated or occurs at the back pressure-side coupling point. The control pressure, which can be set and changed, is present at the control pressure-side coupling point.
In an implementation of this embodiment, the pre-pressure-side coupling point of a first valve is in a fluid connection with the control pressure-side coupling point of a second valve of the valve device. Thanks to this embodiment, the pre-pressure, which is present at this first valve, acts at the same time as a control pressure for the second valve. This implementation therefore eliminates the need for a fluid conveying unit for the second valve.
According to the present invention, the valve device comprises a first valve and at least one second valve. In one embodiment, the valve device comprises a second valve and additionally a third valve. The three valves are connected in parallel. All three valves are arranged between the source-side fluid guide unit and the patient-side fluid guide unit.
In one implementation of this embodiment, the pre-pressure-side coupling point of the second valve is in a fluid connection with the control pressure-side coupling point of the third valve. The pre-pressure at the second valve therefore acts as a control pressure for the third valve.
In one embodiment, a controllable fluid conveying unit, especially a pump or a blower, is associated with the first valve. This fluid conveying unit is capable of setting the control pressure, which is present at the first valve. The control pressure, which is present at the second valve, becomes established depending on the pre-pressure, which is present at the second valve, and on the control pressure, which is present at the first valve. This embodiment eliminates in many cases the need for a further fluid conveying unit for the second valve or for the optional third valve.
The invention further relates to a connection arrangement comprising a connection device according to the invention and a fluid conveying (delivery) device. The connection arrangement is capable of supplying a patient-side coupling unit with a gas. The fluid conveying device is capable of conveying (delivering) the gas through the connection arrangement to the patient-side coupling unit. The gas flows from a source first through the source-side fluid guide unit, afterwards through the valve device, and afterwards through the patient-side coupling unit to the patient side coupling unit. The source is a medical device or supply connection or supply port, e.g.
As a rule, the gas comprises oxygen. In one embodiment the gas has the form of a gas mixture, and the gas mixture additionally comprises at least one further component, e.g. breathing air and/or and at least one anesthetic. This gas mixture is created in a mixing point or develops in the mixing point wherein at least two gas components are remixed in the mixing point. This mixing point serves as the source for the gas (the gas mixture).
The invention further refers to a discharge arrangement comprising a connection device according to the invention. The gas flows from the patient-side coupling unit through the patient-side fluid guide unit, afterwards through the valve device, and afterwards through the source-side fluid guide unit to a sink for the gas. This sink can be a fluid receptacle (fluid receiving unit) or a medical device. In particular the gas is breathed air (exhaled air) which a patient exhales wherein the patient is connected with the patient side coupling unit.
In addition, the invention relates to a fluid circuit arrangement. This fluid circuit arrangement is capable of at least temporarily establishing and keeping a fluid circuit between a medical device and a patient side coupling unit. In particular, the medical device is a ventilator, especially an anesthetic machine. The fluid circuit arrangement comprises a connection device according to the embodiment wherein the connection device connects the medical device with the patient-side coupling unit. The connecting device comprises two source-side fluid guide units, namely a source-side inspiration fluid guide unit and a source-side expiration fluid guide unit. The connecting device further comprises two patient-side fluid guide units, namely a patient-side inspiration fluid guide unit and a patient-side expiration fluid guide unit. In addition the connecting device comprises two valve devices, namely an inspiration valve device and an expiration valve device. In other words: The fluid circuit arrangement comprises an inspiration connection device according to the invention and an expiration connecting device according to the invention. Both connecting devices according to the invention connect the medical device with the patient-side coupling unit.
The gas flows at least temporarily along the following fluid circuit:
Preferably, a fluid conveying device establishes and keeps a flow of gas in this fluid circuit.
The present invention will be described below on the basis of an exemplary embodiment. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
In the drawings,
The present invention is used in the exemplary embodiment to artificially ventilate a patient Pt. A patient-side coupling unit 9, for example, a breathing mask or a tube or a catheter, is attached at or in or on the body of the patient Pt.
The connection device according to the present invention is used twice in the example according to
A blower 2 or another fluid delivery unit (conveying unit) suctions ambient air through an inlet E. A filter 12 filters particles and harmful substances out of the ambient air suctioned.
A supply port 20 provides pure oxygen, The supply port 20 is stationary in the exemplary embodiment and is arranged in a wall W and it supplies the pure oxygen with a pressure that is between 2 bar and 5 bar.
A gas of pure oxygen and breathing air is generated or is formed at a mixing point 8. The supply port 20 provides the pure oxygen and the blower 2 provides the breathing air.
It is possible that a mixture of at least one anesthetic and a carrier gas is generated by an anesthetic evaporator and the latter feeds this mixture into the inhalation duct. The gas, which is delivered to the patient-side coupling unit 9, comprises in this embodiment oxygen as well as at least one anesthetic. The patient Pt is anesthetized or sedated thereby.
In one embodiment, the blower 2 generates in the section of the inhalation duct between the mixing point 8 and the patient-side coupling unit 9 a pressure that is between 20 mbar and 100 mbar and preferably between 30 mbar and 60 mbar and which is constant over time in one embodiment, of course, aside from inevitable fluctuations based on the operation of the blower 2. In another embodiment, the pressure and/or the volume flow, which is generated by the blower 2, is controlled with the control gain of following a predefined time course.
In addition, the following components of the ventilator 100 are arranged in the inhalation duct:
A pressure reducer is defined as a component that has a pre (admission, intake) pressure inlet and a back (exit) pressure outlet, wherein the pressure at the back pressure outlet is at most equal to the pressure at the pre-pressure inlet and is, in addition, at most equal to an upper pressure threshold, which is predefined by the construction of the pressure reducer.
A line 21 leads from the supply port 20 for pure oxygen to an inlet of the pressure reducer 1. A line 22 leads from an outlet of the pressure reducer 1 to the mixing point 8. A line 23 leads from an outlet of the blower 2 to the mixing point 8. A line 24 leads from the mixing point 8 to the inhalation proportional valve 4.1. A line 25 leads from the inhalation proportional valve 4.1 to the patient-side coupling unit 9. The lines 21 through 25 belong to the inhalation duct of the exemplary embodiment. The line 24 acts as a source-side fluid guide unit arranged upstream, and the line 25 acts as a patient-side fluid guide unit of the inhalation connection device 110, which fluid guide unit is arranged downstream.
The volume flow sensor 6.1 measures an indicator of the volume flow through the inhalation duct and upstream of the inhalation proportional valve 4.1, namely, through the line 24. To measure the volume flow, the volume flow sensor 6.1 measures the pressure difference ΔP upstream and downstream of the pneumatic resistance 5.1 and derives the volume flow in the inhalation duct 21 through 25. The pressure sensor 7.1 measures the pressure in the inhalation duct 21 through 25, downstream of the inhalation proportional valve 4.1 and in the line 25 in the exemplary embodiment. The pressure relief valve 10 opens when the pressure in the line 25 exceeds a predefined threshold, and it reduces thereby the pressure in the line 25.
The pneumatic resistance 5.1 is arranged upstream of the inhalation proportional valve 4.1 in the example shown. It is also possible that the inhalation proportional valve 4.1 is arranged upstream of the pneumatic resistance 5.1.
The control device (control unit) 3 receives measured values from the sensors 6.1 and 7.1, processes the measured values and actuates and controls the inhalation proportional valve 4.1 depending on the processed measured values. The control device 3 carries out a closed-loop control with the control gain of having the actual time course of the volume flow in the line 25 follow a predefined desired time course of the volume flow. The volume flow being delivered during the ventilation of the patient Pt may be between 1 L/min and 200 L/min.
It is also possible that the control gain is to have the actual time course of the pressure in the line 25 follow a predefined desired time course.
The following components are arranged in the exhalation duct:
PEEP means positive end-expiratory pressure. It is possible that the same component carries out the function of both the exhalation proportional valve 4.2 and of the PEEP valve 11.
A line 31 leads from the patient-side coupling unit 9 to the exhalation proportional valve 4.2. A line 32 leads from the exhalation proportional valve 4.2 to the PEEP valve 11. A line 33 leads from the PEEP valve 11 into the surrounding area or back to the inhalation duct 21 through 25. The lines 31 through 33 belong to the exhalation duct, through which exhaled air is sent. The line 31 acts as a patient-side fluid guide unit arranged upstream, and the line 33 acts as a source-side fluid guide unit of the exhalation connection device 120, which [fluid guide unit] is arranged downstream.
If the exhaled air is sent through the exhalation duct 31 through 33 back to the inhalation duct 21 through 25, a closed ventilation circuit is formed. The return is shown schematically in
The exhalation proportional valve 4.2, the pneumatic resistance 5.2 and the sensors 6.2 and 7.2 are configured in the same manner as the corresponding components in the inhalation duct 21 through 25. The PEEP valve 11 ensures that the end-expiratory pressure in the lungs of the patient Pt does not drop below a predefined threshold.
Both the volume flow, i.e., the flow of gas per unit of time through the inhalation duct 21 through 25 to the patient-side coupling unit 9 and the volume flow from the patient-side coupling unit 9 through the exhalation duct 31 through 33 can each follow a respective predefined time course in the exemplary embodiment.
A pre-pressure and a back pressure are present at the two respective proportional valves 4.1 and 4.2. The pre-pressure at the inhalation proportional valve 4.1 is the pressure in the line 24, and the back pressure is the pressure in line 25. The pre-pressure at the exhalation proportional valve 4.2 is the pressure in the line 32, and the back pressure is the pressure in line 33. The back pressure is lower than, equal to or at most equal to the pre-pressure.
As a rule, the exhalation proportional valve 4.2 is closed during the inhalation phase, and the time course of the volume flow Vol′ is controlled by the inhalation proportional valve 4.1. Conversely, the inhalation proportional valve 4.1 is closed and the time course Vol′ is controlled by the exhalation proportional valve 4.2 during the exhalation phase. Two exceptions are suggested in
Thanks to the flexible seal 43.1, 43.2, 43.3, the closure 42.1, 42.2, 42.3 is movable relative to the valve seat 41.1, 41.2, 41.3. The closure 42.1, 42.2, 42.3 acts as a valve body, and the valve seat 41.1, 41.2, 41.3 acts as a valve body seat.
A first feed line 24.1 leads from the line 24 to the valve seat 41.1, a second feed line 24.2 leads from the line 24 to the valve seat 41.2, and a third feed line 24.3 leads from the line 24 to the valve seat 41.3. A pre-pressure is present from one side, at the bottom in the examples shown, at the closure 42.1, 42.2, 42.3. The respective pre-pressure is equal in one embodiment to the pressure in the feed line 24.1, 24.2, 24.3. The side of the valve seat 41.1, 41.2, 41.3 which points towards the feed line 24.1, 24.2, 24.3, acts as the pre-pressure-side coupling point of the valve 40.1, 40.2, 40.3. The pressure in the feed line 24.1, 24.2, 24.3 and hence the pre-pressure depend on the pressure in the line 24, which leads to the inhalation proportional valve 4.1. In one embodiment, the pressure is equal in the lines 24, 24.1, 24.2, 24.3.
From the other side, a control pressure is present at the closure 42.1, 42.2, 42.3, namely, from the top in the examples shown. The seal 43.1, 43.2, 43.3 belongs to a control pressure-side coupling point of the valve 40.1, 40.2, 40.3. At least two control pressures present may differ from one another. Different embodiments differ from one another, among other things, in how this control pressure is generated and changed when needed.
A first discharge line 25.1 leads from the gap between the closure 42.1 and the valve seat 41.1 to the line 25, a second discharge line 25.2 leads from the gap between the closure 42.2 and the valve seat 41.2 to the line 25, and a third discharge line 25.3 leads from the gap between the closure 42.3 and the valve seat 41.3 to the line 25 The gap between the closures 42.1, 42.2, 42.3 and the respective valve seats 41.1, 41.2, 41.3 belongs to the back pressure-side coupling point of the valve 40.1, 40.2, 40.3.
If the control pressure is higher than the pre-pressure, then the closure 42.1, 42.2, 42.3 is pressed onto the valve seat 41.1, 41.2, 41.3 and it closes this valve seat 41.1, 41.2, 41.3, doing so ideally completely. If, by contrast, the pre-pressure is higher than the control pressure, the closure 42.1, 42.2, 42.3 is moved away from the valve seat 41.1, 41.2, 41.3. As a result, a volume flow takes place through the gap between the valve seat 41.1, 41.2, 41.3 and the closure 42.1, 42.2, 42.3. This volume flow leads to a back pressure in the line 25.1, 25.2, 25.3. In one embodiment, this back pressure is equal to the pressure in the line 25. The volume flow depends on the effective cross-sectional area between the closure 42.1, 42.2, 42.3 and the valve seat 41.1, 41.2, 41.3.
It will be explained below why at least two valves connected in parallel with a respective valve seat each, with a closure and with a seal are used according to the present invention rather than a single valve only. As was already described, the required volume flow can vary between 1 L/min and 200 L/min. This great variation notwithstanding, the time course of the actual volume flow shall differ only slightly from a required time course. This control gain is accomplished by a closed-loop control. It may happen precisely in case of a relatively low volume flow that the distance between the closure and the valve seat varies over the circumference of the closure and/or that the closure vibrates or “dances” on the valve seat, similarly to a lid on a pot, which is filled with boiling water. This may lead to a variation, for example, oscillation, of the time course of the actual volume flow in an undesired manner, and/or to said time course not being able to be measured in a reliable manner. The inventors found in experiments that this undesired effect occurs more rarely and in a less intensive manner when at least two parallel valves are used than when only a single valve is used.
The valve seat 41.1 has a smaller diameter than the valve seat 41.2 in the examples shown in
In the embodiment according to
Both pumps 44.1, 44.2 are in connection on the inlet side with the line 24. The pressure in the line 24 is equal—aside from inevitable leaks and other pressure drops—to the pressure that is generated by the blower 2 at the outlet thereof. The pump 44.1 generates on the outlet side the control pressure for the smaller valve 40.1, and the pump 44.2 generates the control pressure for the larger valve 41.2. The effect of the pump 44.1 is that the control pressure, which is present at the smaller valve 40.1, is higher or also lower than the pressure in the line 24 and hence higher or lower than the pressure that is generated by the blower 2. For example, the blower 2 generates a pressure of 30 mbar constantly, and the pump 44.1 increases or decreases this pressure by a maximum of 20 mbar depending on the actuation, so that the control pressure is between 10 mbar and 50 mbar at the smaller valve 40.1. The pump 44.2 operates in the same manner. Since the control pressure-side coupling point of the valve 40.1, 40.2 is in a fluid connection with the line 24, it is not necessary for the pump 44.1, 44.2 to generate the control pressure alone, and the control pressure is rather generated by a superimposition of the pressure in the line 24 and the pressure at the outlet of the pump 44.1, 44.2.
In one embodiment, a respective characteristic is predefined for each valve 40.1, 40.2 and is stored in a computer-analyzable form. The control device 3 automatically analyzes the respective characteristic in order to actuate the pump 44.1, 44.2. The characteristic indicates the control pressure to be reached as a function of the volume flow to the valve 40.1, 40.2. The characteristic may depend on the pressure that is generated by the blower 2.
A respective working range is predefined in the example according to
In one embodiment, the control device 3 uses the volume flow Vol′ in the line 24, which was measured by the volume flow sensor 6.1, and actuates the two pumps 44.1 and 44.2 as a function of the characteristics stored. The control device 3 controls in another embodiment the respective control pressure, which is present at the valves 40.1 and 40.2. The volume flow sensor 6.1, which was mentioned already, therefore measures, on the one hand, the volume flow in the line 24. A volume flow sensor 6.1.1 measures the volume flow in the feed line 24.1 from the line 24 to the smaller valve 40.1, and a volume flow sensor 6.1.2 measures the volume flow in the feed line 24.2 from line 24 to the larger valve 40.2. Two pneumatic resistances 5.1.1 and 5.1.2 are therefore arranged in the two feed lines 24.1 and 24.2 to the valves 40.1 and 40.2 in one embodiment, and the volume flow sensor measures the pressure difference as an indicator of the volume flow. The embodiment with a plurality of volume flow sensors generates redundancy and/or makes an error correction possible, because the volume flow in the line 24, which is measured by the sensor 6.1, is ideally equal to the sum of the volume flows from line 24 to the two valves 40.1 and 40.2, which volume flows are measured by the sensors 6.1.1 and 6.1.2.
The control pressures for the two valves 40.1 and 40.2 can be set in the same manner when the two valves 40.1 and 40.2 have valve seats and closures having the same diameter. The two control pressures may be equal. It is also possible that the control pressures are different for valves 40.1, 40.2 of equal size.
Only one actuated pump 44.1 is likewise used in the embodiment according to
P_c=P_v−R(5.1.1)*Vol′(27),
wherein P_c is the control pressure at the larger valve 40.2, P_v is the pre-pressure at the smaller valve 40.1, R(5.1.1) is the pneumatic resistance of the line 27 and Vol′(27) is the volume flow through the line 27. A high-volume flow through the feed line 24.1 also leads to a high-volume flow through the line 27 and hence to a low control pressure at the larger valve 40.2, which will therefore open wider. This leads, in turn, to a higher volume flow from the larger valve 40.2 into the line 25.
In the embodiments that are shown in
The embodiment according to
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 100 254.3 | Jan 2022 | DE | national |
