WO2011144541A1

WO2011144541A1 - Diaphragm valve and method to control a flow

Info

Publication number: WO2011144541A1
Application number: PCT/EP2011/057810
Authority: WO
Inventors: Göran Cewers
Original assignee: Mindray Medical Sweden Ab
Priority date: 2010-05-17
Filing date: 2011-05-15
Publication date: 2011-11-24

Abstract

The invention relates to a device and method for controlling the flow of a fluid through a flow channel. The flow is controlled by means of a flexible conduit with flexible circular segments (10, 11) compressed along the length of the conduit, whereupon the flexible elements collapse against a circular wall.

Description

DIAPHRAGM VALVE AND METHOD TO CONTROL A FLOW

Related applications

The present application relates to the following applications of the same inventor as the present application with the following titles: "VALVE AND METHOD TO CONTROL A FLOW

THROUGH THE VALVE" (US61/345.623); "MECHANICAL AMPLIFIER, SYSTEM OF SAID

AMPLIFIERS AND METHOD FOR MECHANICALLY AMPLIFICATION OF A MOTION"

(US61/345,625); "VALVE AND METHOD TO CONTROL A FLOW" (US61/345,628); "MECHANICAL TRIMMING DEVICE AND TRIMMING METHOD" (US61/345.733); "MECHANICAL TEMPERATURE COMPENSATION MEANS, METHOD FOR ASSEMBLY SAID MEANS AND METHOD FOR

MECHANICALLY TEMPERATURE COMPENSATING" (US61/345.756); which all are incorporated herein by reference in their entirety for all purposes.

Background of the Invention

Field of the Invention

The invention pertains in general to the field of valves. More particularly, the invention relates to a valve device for mechanically controlling the flow of at least one fluid through at least one channel. Even more particularly, the invention relates in some embodiments to valves for breathing machines like medical ventilators.

Description of Prior art

It is known that, when designing low pressure valves, especially in the field of gas control in medical ventilators is it of high importance that the flow channel in the valve has low flow resistance and no or little turbulence. In some applications requirements are high concerning cleaning of contaminated parts of the valve. Moreover, it is often desirable for the design to be small and light and that the actuator controlling the valve may be made small and isolated from the flow channel.

Examples of low pressure valve applications are expiration valves, patient pressure relief valves, mixer valves and flow valves in low pressure systems.

Today, the commonest design of low pressure valves comprises a circular disk lying against the end of a tube forming a valve seat. US patent 5,127,400 discloses an example of such a design. The drawbacks of such a design are the complexity of the flow channel, which causes turbulence and cleaning issues. Moreover, the entire circular disk is exposed to a pressure, while the flow only depends on the outer edge of the disk. Thus an unnecessarily strong, heavy and expensive actuator is needed to control this type of valve.

Another example is international patent application WO 2008/112332 that discloses an inline valve. The inline valve includes, a housing, a choke member in operable communication with the housing, a portion of the choke member being substantially immobile relative to the housing and a portion of the choke member being mobile relative to the housing. The inline valve further includes, an actuator in operable communication with the movable portion of the choke member, the actuator selectively causing the choke member to deform radially. However, the valve disclosed in WO

2008/112332 only uses one area that can be deformed and can therefore not be used as a valve device between two fixed end positions. Further, the valve can only choke a flow from the inside against a hard conduit. WO 2008/112332 does not disclose anything regarding how to avoid deformation and wear nor how to be able to simply clean or disassemble the valve. Thus the disclosed valve is not suitable for medical devices.

United States patent number US 5,119,861 discloses a normally closed valve for controlling flow of fluid material through a straight, non-tapered conduit has resilient elastomeric seal attached to the perimeters of two axially aligned rigid end plates. Elasticity of elastomeric seal draws end plates together while radially expanding so as to engage and seal against the inner wall of conduit. This valve may be opened by axially separating the two opposing end plates using a locally actuated displacer mechanism attached to one of the end plates, causing the elastomeric seal to radially contract and the valve to open. The issue with the design of this valve is almost the same as for WO 2008112332. Even though US 5,119,861 discloses a valve having at least two resilient members the configuration of the device makes it only usable when one end is displaceable. Thus it cannot be used in-between two fixed end-points. Since the valve is normally closed, the focus and the use of more than one resilient member are to increase the sealing effect for specific applications.

Hence, an improved valve would be advantageous and in particular an actuator controlled valves allowing for increased flexibility, cost-effectiveness, and/or fulfilling the above-mentioned criteria, of a small and light actuator controlled valve having low flow resistance and no or little turbulence, would be advantageous.

Summary of the Invention

Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing a device and a method, according to the appended patent claims.

A valve designed to be small and light and which actuator controlling the valve may be made small and isolated from the flow channel is provided, which is highly desirable. Particularly if the valve is configured to have low flow resistance and no, or little, turbulence. Moreover for some applications the requirements are high concerning cleaning of contaminated parts of the valve which may be provided by embodiments allowing for separating the valve device from the actuator unit and the tube systems connectable to the patient.

According to a first aspect of the invention a valve is provided comprising: at least two flexible segments, each having at least one flexible zone; at least one valve seat, corresponding to at least one of the flexible segments, is positioned either outside and/or inside of the at least two flexible segments; at least one flow channel located between the flexible segments and the valve seat for passage of a fluid; at least one actuator unit arranged to axially compress or decompress the flexible segments for control of a flow of the fluid through the flow channel. One of the flexible segments, by a motion of the actuator unit, is either angled radially towards, or straightened up from the valve seat, and wherein at least one other of the flexible segments is positioned to allow said axial movement.

In an embodiment where the flexible segments are in their normal position, the valve is open and a flow, which may be described as essentially without turbulence, of at least one fluid may occur in the channel between the flexible segments and at least one valve seat. The flexible segments are part of a flexible conduit. Further, the flexible segments may be made as an integrated part. A flexible segment of the present invention is provided as having one or more zones which are operable as articulations. Whereby the flexible segment may be controllably angled or protruded radially towards a valve seat when being exposed to an axial compressive or decompressive motion from an actuator unit. With increasing angulation or protrusion of at least one of the flexible segments, at least one area of the protruded flexible segment will touch the valve seat.

Preferably, the touching area is a flexible zone and preferably the area or zone is designed so that a tight sealing effect occurs between the angled flexible segment and the valve seat.

To facilitate the positioning of the valve between two non-flexible in and outlet channels, additional flexible segments may be utilized so that the axial compressing or decompressing movement of the, for the valve, choking flexible segment can be carried out. Thus strain on the material or on the mountings of the non-flexible in- and outlet channels is avoided. Strain or stress could cause lasting deformation or wear. For medical use wear such as cracks in the conduit could be an issue since it may increase the risk for contamination. Deformation of wear may also have affect the reliability of the equipment e.g. could break down in critical situations. Such drawbacks are effectively avoided by embodiments.

Other advantages by using at least two flexible segments are when it is desired to alternately controlling a fluid flow through two channels and/or parts of a channel. In an embodiment of this kind the first flexible segment is used for opening and closing the first flow channel at the same time as the second flexible segment is used for opening and closing e.g. a second flow channel. They work together to facilitate the axial movement and thereby avoiding deformation and wear on both flexible segments. This design has also the advantage of the flow being controlled in both flow channels simultaneously. The flexible segments may in this embodiment use the same valve wall but may also be provided in a configuration such that each flexible segment that is controlling a flow has a separate valve wall.

Embodiments may be extended to include, where necessary, more than two flexible segments and several flow channels. The term axial directed movement/motion herein refers to a direction along or against the direction of flow, which takes place between two openings positioned at each side of a flow channel.

The term radial directed movement/motion refers to movement substantially vertically to the direction of the flow. It may be provided in embodiments as any substantially radial movement of this kind, e.g. by a protruding flexible segment directed towards a valve seat.

In some embodiments of the invention, the flexible segments and the valve seats are arranged and positioned relative each other so that the flexible segments are arranged in at least one position that allows a flow being substantially without turbulence through the flow channel of the valve.

In some embodiments of the invention the flexible segments are configured to have a side in at least one position with even characteristic located on at least a flow side of the channel. This configuration allows for an essentially non-turbulent flow in, for the channel, open position, which decreases the flow resistance of the fluids through the flow channel.

In some embodiments, the valve may be configured to be used with medical ventilators. The fluid controlled by the valve is thus breathing gas. The valve is preferably an expiratory valve. It may also be provided as an inspiratory valve for low pressure applications. Regulation of pressure and flow is thus provideable in suitable control loops.

In some embodiments, the axial motion of the valve may be along or against the direction of the flow. In some embodiments a valve seat is provided that may be a rotationally symmetric circular wall located in the center of at least one of the flexible segments.

In some embodiments the valve seat has a rotationally symmetric conical profile and is located in the center of at least one of the flexible segments, downstream.

In some embodiments the valve seat has a rotationally symmetric circular wall that may be an inside of a conduit, positioned around at least one of said flexible segments.

In another embodiment of the valve, the construction material is provided in the flexible segments of the valve and the valve seats are autoclavable and/or the construction material in the flexible segments and the valve seats are disposable, or the design may comprise parts being autoclavable combined with parts being disposable. Examples of such autoclavable materials include silicone rubber, stainless steel etc.

Choosing these materials allows the valves to be used in medical devices such as a breathing apparatus. Valves contaminated by the patient can thus be safely cleaned and disinfected between different patients. Such valves may be used in medical ventilators such as expiration valves for breathing systems.

In some embodiments, the actuator unit of the valve is at least one piezoelectric actuator. In other embodiments the actuator unit may comprise at least one coil actuator. Other types of actuator units may be suitable.

Yet another advantage of the design is that actuator unit of the valve may be arranged without contact with the flow channel, and thus the actuator needs not be autoclavable. This simplifies handling and increases the life-time of the actuator.

In some embodiments the valve has an integrated flow meter. In particular, at least two ultrasound transceivers are placed along at least one of the flow channels to measure the flow through the channel. Hence a compact unit can be provided. The unit has the advantage of allowing rapid control of the flow through the valve, since the distance between the flow meter and the valve may be kept short, turbulence can be avoided.

In some embodiments the valve has a flexible section connected to the actuator unit. By means of motion of the actuator unit, the flexible section is compressed simultaneously as one of the flexible segments. Thus the flexible section and the flexible segment are protruded towards each other to control the flow through the channel.

In another aspect, the invention comprises a method for controlling a flow through at least one fluid passage. The method comprises, using at least one actuator unit, axially compressing or decompressing at least two flexible segments of a valve device. At least one of the flexible segments is being compressed and at least one second flexible segment is being expanded. At least one other of the flexible segments is protruding substantially radially towards or straightening up from a

corresponding valve seat for controlling the flow through the fluid passage.

The advantages of this method are the same as for the equipment described above. A substantially non-turbulent flow of one or more fluids can be created through one or more flow channels and the flow can easily be choked when needed. The flow control is rapid and reliable with a compact unit. Piezoactuators may be used which gives a low energy consumption. Since more than one segment, for controlling a flow, may be controlled by the same actuator, for example may an alternately controlling be simultaneously performed for two channels.

Further embodiments of the invention are defined in the dependent claims, wherein features for the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Brief Description of the Drawings

These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

Figures 1 and 2 are schematic views showing an exemplary embodiment of flexible segments; Figure 3 is a schematic view showing several exemplary embodiments of valve configurations;

Figure 4 is a schematic view showing an example of how the flexible tube segments may be combined.

Figures 5-6 are schematic views showing axial cross-sections of exemplary embodiments of low pressure valve devices with a flexible conduit surrounding a rotationally symmetric body;

Figure 7 is a schematic view showing an axial cross section of a complete valve device without an actuator unit;

Figure 8 is a schematic view showing the outside of an example of a valve configuration from above;

Figures 9-11 are schematic views of various examples of low pressure valves and how they may be connected with an actuator unit;

Figures 12-14 are schematic views of various examples of low pressure valves where the flexible segment is located inside a hard conduit;

Figure 15 is a schematic cross sectional view of an embodiment of a low pressure valve with integrated flow meter comprising ultrasound transceiver elements;

Figure 16 is a schematic view showing how grooves in the flexible segment have been added to reduce the segment's axial compression resistance;

Figure 17 is a schematic view showing an exemplary embodiment of a low pressure valve with a surrounding hard conduit; and

Fig 18 is showing a schematic view of an exemplary embodiment of the valve having a flexible segment with a round shape and with a different closing mechanism compared to the aforementioned;

Figure 19 is a schematic view showing an exemplary embodiment of a low pressure valve with a flexible segment surrounding a rotationally symmetric body having a flexible section that may protrude by the motion of an actuator unit; and Fig. 20 is a flowchart of a method.

Description of embodiments

Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

Figure 1 is a schematic view showing the cross section of an exemplary embodiment of a first flexible segment. According to a principle of the invention, flexible segment 10 is in an unaffected state, while fist flexible segment 11 is in a compressed state. When in the compressed state the flexible segment may have a protrusion 12 acting as a flexible zone being an articulation.

Additionally and/or alternatively the protrusion may be circular. Further, in some embodiments the protraction may be touching a valve seat when the first flexible element 10 is in its compressed state 11 (Fig. 1 bottom). When the first flexible segment 10 is in its unaffected state (Fig. 1 top) the valve device is normally open (NO).

Additionally and/or alternatively, the flexible segment may be an integral part of a flexible conduit. The flexible segment may be provided as a single monolithic structure. This provides for a cost effective manufacturing of the parts.

Figure 2 is a schematic view showing the cross section of an exemplary embodiment of a second flexible segment. According to a principle of the invention, the second flexible segment 20 is in an unaffected state (Fig. 2 top), while the second flexible segment 21 is in expanded state (Fig. 2 bottom).

Additionally and/or alternatively, the second flexible element may have a similar soft valve element as the first flexible segment. Further, the second flexible segment may be part of a flexible conduit. Additionally and/or alternatively, the first flexible segment and the second flexible element may be an integral part of a flexible conduit. The flexible segments may be provided as a single monolithic structure, as e.g. shown in Fig. 3.

The flexible element has at least one flexible portion to allow bending of the element in a direction substantially perpendicular to the direction of actuating (pointed arrows in Fig. 1 , and Fig. 2). Non-flexible portions may be combined with the at least one flexible portion of the flexible element. In the illustrated example in Figs. 1-17, one or more substantially triangular non-flexible portions are connected with flexible joint portions allowing for the hinged movement thereof. Thus, a pivoting movement of the flexible element in a substantially radially direction is provided by a substantially axially actuating movement thereof.

Figure 3 is schematically illustrating three exemplary valve configurations 1 , 2 and 3. Here, each valve configuration is having a flexible element. The flexible element may be, advantageously integral, combinations of at least two flexible elements. In these examples the flexible element comprising a first 10, 12 and a second 20, 21 flexible segment, as illustrated in Figures 1 and 2.

Additionally and/or alternatively in some embodiments, other combinations of the flexible segments are provided to obtain a flexible segment.

These illustrated arrangements are for controlling the flow of a fluid without deformation and wear of the flexible element. Particularly is deformation and wear of the first flexible segment 10, 11 avoided upon repeated folding by utilizing the presented flexible element.

Additionally and/or alternatively in some embodiments, at least one flexible element may be a part of a flexible conduit which in turn may be part and/or a portion of a flow channel. Wherein at least one of the flexible elements is the opening or closing portion of a valve, e.g. the flexible element may be configured to choke the flow of a fluid. Depending on the design of the valve device, the closing of the channel could be either conducted either partially, completely or partially and/or completely. Hence, the fluid flow can be precisely controlled by the valve. Control loops based on sensor input of e.g. flow and/or pressure may be provided for a precise control of the flow in the channel, based on input from the sensor(s) and actuated by the valve to a desired value in the control loop. The desired value may e.g. be provided from a medical ventilator control unit. The desired value may e.g. be based on user input or desired breathing patterns or breathing modes.

In valve configuration 1 , 301 is the inside or outside of a hard (non-flexible, non-resilient) conduit where at least a part of the conduit 301 may be a valve seat 330. Elements 30 and 31 are a first and a second flexible segment, respectively. The axial movement of a ring element 32 is changing the state of the first and second flexible segments and thus controlling the flow through the channel 350. Preferably the ring element 32 may be made of a hard material. Both 320 and 321 are flexible zones configured to allow the flexible segments to collapse by angulation or protruding. Additionally the flexible zone 320 may also be a touching area.

Alternatively and/or additionally in some embodiments, the flexible zone 320 may be configured to provide a sealing effect when touching or getting into apposition with the valve seat 330.

In the shown example, the second flexible segment 31 is being collapsed by angulation or protruding in the same direction as the first flexible segment 30. The second flexible element 31 may also be positioned to be angled or protruded in the opposite direction.

In valve configuration 2, a second hard conduit 302 is introduced to form a second valve function of the valve device. Thus the second hard conduit may have an area forming a valve seat 331. This configuration of the valve device has two flow channels 351 and 352 and may have an inlet and/or an outlet 311 (opening illustrated between the valve seats 331 , 330 in Fig. 3, middle). In this configuration the second flexible segment 31 may be configured as the first flexible segment 30. Thus a closing and/or choking movement is provided, whereby the flow of the fluid in the second flow channel 352 may be either partially and/or completely closed or choked.

The flow of the fluid can therefore be selectively controlled to pass to or from the inlet/outlet 311 through either the first flow channel 351 or the second 352. Alternatively and/or additionally, in some embodiments, the channels are not completely closed by the first and second flexible segments 31 , 32. This could be used to obtain a proportional mixing of, for example two fluids, at an outlet 311. It could also be used to allow a first portion of a fluid to pass through the first flow channel 351 and a second portion of a fluid to pass through the second flow channel 352, from an inlet 311.

The third configuration of a valve device 3 works according to the same principles as the previous valve configuration 2. The difference is that the second hard conduit 331 is on the opposite side of the flexible element in relation to the first hard conduit 320. This configuration allows alternatively flows to pass through a first flow channel 353 and a second flow channel 354.

Figure 4 is a schematic view showing an example of how flexible segments may be combined to form a flexible conduit. The flexible segments may be combined in a plurality of ways to obtain various valve functions. In this exemplary combination 40, 42 show axially compressed flexible segments and 41 and 43 show axially decompressed flexible segments. 44, 45 and 46 are fastening rings surrounding the flexible conduit. The fastening rings 44, 45, 46 may either be stationary or may be pushed a distance using an actuator unit and thereby compressing or decompressing adjacent flexible segments. Depending on the configuration of the segments and the function of fastening rings the illustrated example could be considered as one flexible element comprising all four flexible segments or as two flexible elements, each having two flexible segments.

Figure 5 is a schematic view showing an exemplary embodiment of a low pressure valve with a flexible conduit surrounding a rotationally symmetric body 51. The right drawing illustrates how the circular ring 54 is moved a distance 55 from the first fastening ring 53 and towards the second fastening ring 52. The movement of the circular ring 54 causes the first flexible segment 50 to collapse towards and then pressed against the rotationally symmetric body 51 forming a valve seat. In the collapsed state of the flexible segment 50, the valve device becomes closed or choked. It should be noted that the second flexible segment 56 is moved in the opposite direction. Hence, when the first segment 50 is compressed, the second segment will be stretched or expanded and thereby facilitates the movement of compression of the first segment 50. At the same time, the second segment 56 protrudes into the flow channel. However, this does not cause turbulences as the valve gets closed, see Fig. 5 right.

Figure 6 is an axial cross-section showing another exemplary embodiment of a low pressure valve. The valve device is a modification of the valve shown in Figure 5. In this exemplary embodiment the lower part of the flexible conduit, the flexible segment 66 is slightly angled in the axial direction. Thus the flexible conduit has a conical shaped which may optimize the flow channel for further connection to e.g. a tube. This design has also the advantage of further decreasing the turbulence of the flow due to the conical shape.

The valve device, such that shown in Fig. 6, may be obtained using a soft conduit. The flexible conduit may be manufactured of an elastic or flexible material, for example silicone rubber. At least a portion of the flexible conduit may be a flexible element having at least two flexible segments, such as a first 60 and a second 66, as an integrated part.

The flexible element of the embodiment in Fig. 6 is fastened at its end points 62, 63. End point

62 has a larger cross section than end section 63. A movable ring element 64 exposes the flexible element to an axial movement by moving a distance 65 in the direction towards one of the ends points 62, 63. Thus the first flexible segment 60 is being subject to compressing force and the second flexible segment 66 is being subject to a decompressing force, or the other way around depending on the direction of the motion.

Further, Figure 6 shows a valve arrangement in two different states. The left hand drawing shows the valve device in open position and the right hand drawing in closed position.

The left hand drawing shows a first flexible segment 60 in uncompressed state, while a second flexible element 66 is in compressed state. A flexible zone 69 being a circular shaped protrusion of the first flexible element 60 acts according to the aforementioned flexible zone. In this state the valve device is normally open.

Moreover, the valve device includes a rotationally symmetric hard body 61 centered inside the flexible conduit. The hard body 61 may be aerodynamically designed to minimize the flow resistance in the valve device. The body 61 having an area being a valve seat 619 towards which the first flexible element 60 operates.

Body 61 may be fastened to fastening rings 62, 63 by supporting elements, which are not shown in the figures.

When the valve device is open, as shown in the left hand drawing of Fig. 6, the inside of the flexible conduit is essentially even. This combined with the design of the center body 61 causes a very low flow resistance in a valve device of the present invention. As hereinbefore described, the flow channel of the valve device may be closed by axially moving ring element 64 a distance 65 towards either of the fastening ring 62 or 63. Thus compressing flexible segment 60 and at the same time expanding flexible segment 66. This will cause the flexible segment 60 to be angled towards the body 61.

Alternatively and/or additionally, the flexible segment may collapse and be pressed against a valve seat, i.e. an area of body 61 , and thereby completely close or choke the flow through the flow channel.

Additionally and/or alternatively, in some embodiments, ring element 64 may also be positioned in-between closed and open position. Thus valve may not be completely closed and a proportional valve is provided.

In the closed or proportional position of the valve device, the flow profile may no longer be at optimum. This may have no or little importance as there is no or limited flow through the valve device.

In some advantageous embodiments, the flexible segment 60 may have a profile that differs slightly compared to the flexible segment 66. The triangular shaped sections are stripped at the top to reduce the weight of the segment, thus raising the system's resonance frequency. Additionally, the segment 66 may also be made lighter in a similar fashion.

The ring 64 may also be made extra light, e.g. by using a cross-section having a U-shape, T- shape or similar shapes.

The flexible segment 66 has an inner profile being conically shaped, thereby differ from the flexible segment 60. The advantage of this design is, when the valve device is open the flow profile is more favorable since an even surface is obtained on the flow side. Also, less movement needs be absorbed by this segment, whereby it may be made smaller and lighter, which helps to increase the resonance frequency in the system. Thus improved regulating properties are obtainable.

Figure 7 is a schematic view, showing further details of an advantageous exemplary embodiment of a valve device being an expiration valve.

The implementation of the valve device as illustrated in Figure 7 is a valve device which can be dismounted from a chassis of the device which it is intended to be positioned in, such as a medical ventilator. The dismounting may thus be made without having to open the patient's exhalation tube system, allowing the chassis and the actuator portion to be left in-place uncontaminated. The tube system can thereafter be moved for cleaning, destruction or recycling.

When the device shown in Figure 7 is dismounted only parts 77, 78, 700 and 701 remain in the chassis. These parts belong to the actuator portion of the device or the chassis itself. The other parts belong to the valve portion. After the valve portion has been dismounted, the patient tubes can be removed from the end-parts 70 and 71.

An advantage of embodiments is the simplicity in dissembling and assembling the different portions which could be crucial in medical applications. Further advantageous is that parts being hard to clean, and/or expensive to manufacture, e.g. the actuator unit, is kept separate from the flow channel with a small possibility of being contaminated. The valve portion of the device includes three portions which may be separated and autoclaved.

The first portion of the valve portion comprises a first end-part being of a hard material, such as plastic or metal. This part forms the inlet of the expiration valve and includes end-part 70, which also is an inlet, e.g. for expiration breathing gases from a patient. Further, the first portion comprises a fastening means 702 and even further supporting elements 703 which are holding the central body 76 in its position in the flow channel 750.

The second portion of the valve portion comprises a soft conduit made of e.g. silicone rubber, with two flexible sections 73 and 74, as well as end adaptors 72 and 75. The gas channel 750 extends along the entire assembly. A guide ring 79 of a rigid, or hard material such as plastic is mounted over the flexible, or soft(er) conduit of the valve portion as shown in Figure 7. The purpose of ring 79 is to transfer a movement from an actuator portion to axially compression of the first flexible segment 73. This compression will force the flexible segment to be angled or protruded radially into the gas channel 750 towards, and finally against, the central body 76 when the valve is to be closed.

The radially angulation or protrusion may be performed or provided at any suitable angle. The angle depends on shape and configuration of the different parts of the valve device and how they are positioned in relation to each other. Advantageous flow channels may thus be provided with low flow resistance. This is particularly important in medical ventilator expiratory valve applications, as expiration normally is performed passive by the elasticity of the patient's chest and work of breathing is to be reduced.

The third portion of the valve assembly 760 comprises a second end-part 71 of some rigid, or hard material such as plastic. This end-part 71 forms an outlet for the expiration valve. From the outlet the expired patient gas may be conducted further, e.g. to the ambient environment or a vacuum system for evacuation of the exhaust gas.

The actuator portion of the device comprises a flexible foil which upon application of the valve portion in the chassis hooks onto the guide ring 79 and a supporting element 700 having an end 701 which when the valve is closed is moved in the direction of the arrow as shown in Figure 7.

Supporting element 701 is then connected to an actuator unit, which may for instance be an electromagnetic, a thermal, a chemical, a magnetostrictive or a piezoelectric actuator unit. A spherical design of the end portion 701 may provide for an effective coupling to the actuator, while being pivotable in all directions to reduce any wear on the link.

Figure 8 is an exemplary embodiment of a valve configuration. The valve portion in Figure 8 is viewed from above. Inlet part 70, the soft sectioned conduit having a first flexible segment 73 being expanded and a second flexible segment 74 being compressed are also shown in the operational state illustrated by Fig. 8. The valve portion further shows the guide ring 79; fastening ring 78 and outlet part 71. The holders 77 and 708 may be anchored to a chassis. The guide ring 79 is used to actuate, i.e. close and/or open the valve. The opening of the valve can be conducted by restoring the initial position thanks to the elasticity of the conduit, i.e. the valve can be constructed as self-open or normally open Figure 9 is an example showing how an actuator portion may be connected to the valve portion. Here it is seen how a connecting unit. It is here in from of a lever 348, which may be e.g. U or Y shaped, transmits the movement from actuator 406 via a mechanical motion amplifier 405, axis 404 and lower part of lever 403 to the movable guiding ring 343. This is done via an articulation 400, controlled via the pivoting point 401 , such as a hinge or a flexible pivot, and a second articulation 347. The friction may thereby be kept low.

Additionally, the actuator may be fine adjusted using trimming device 409. The trimming device may be of the kind described in US61/345J33.

There may also be a temperature compensating unit 407 positioned in connection to the actuator. The temperature compensating unit may be of the kind described in US61/345J56.

Holders or guiding means 345 and 346 are fastened to the chassis to snap onto the valve body. A fastening ring 344 holds the soft flexible rubber in place and comes off with the valve unit when it is removed from the chassis. Inlet 340 and outlet 341 are connections to the valve unit e.g. for 22 mm conduits. 342 is an end adaptor to connect the flexible conduit to a less flexible tube.

Figure 10 is an exemplary embodiment of a low pressure valve with a flexible conduit being surrounding a rotationally symmetric body. The upper part of Fig. 10 is a view from above while the bottom part of Fig. 10 is a side view. In this example of the valve device, the axially movement conducted to control the valve is done using two actuators. In Fig. 10 two piezoelectric actuators 550 and 551 are shown. Both with linking elements 552 and 553 anchored to the movable guiding ring 554 of the valve device. The valve device can be removed from the parts belonging to the chassis and then, for example, be autoclaved. A holder or bearing element 555 is anchoring the actuator to the chassis.

Figure 11 is an exemplary embodiment of a version of a low pressure valve. Instead of piezo- actuators as in Figure 10, the valve device is actuated by an electromagnetic coil actuator 560 as shown in Figure 11. Here the coil 561 acts directly against the movable disk or guiding ring 562. The electromagnetic coil actuator 560 is based on magnetic attraction or repelling forces that are electrically controlled by a coil producing a controllable magnetic field. The coil may be a loudspeaker coil.

Figure 12 is an exemplary embodiment of a low pressure valve with a rigid, hard conduit 80 surrounding a conduit 750. Disk 88 is moved by a movement of lever 86 a distance 89. When the lever 86 is moved in the direction of the arrow, the valve device is brought to a closed position.

Alternative to use a flexible conduit surrounding a body, the valve device may be made using a hard surrounding conduit 80 and a flexible inner conduit as shown in Figure 12. Here a movement 89 is transmitted by a lever 86 using an articulation and seal 87 to the axis 84 and further on to the movable disk 88. The movement of the movable disk 88 will compress or decompress the flexible segment 83. Thus the flexible element will collapse radially towards the inside of body 80 or straightening up from it.

The valve device further comprises supporting means 85 to hold the valve body in its position. The valve body is preferably aerodynamically shaped. The valve body may have a leading section 81 and a trailing section 82 in the flow channel 750. Figure 13 is an exemplary embodiment of a low pressure valve with the same geometry as in Figure 12. In this example, the lever has been replaced by a piezo-actuator 90 which is encapsulated in the actual flow channel by a valve body 82 being a housing. The movable disc 88 or ring is moved using the mechanical amplifier 91 connected to the movable disc 88 by an axis 84. The movement of the movable disc 88 may bring the valve to an open or closed state. The bellows 94 isolates the environment of the actuator 90 from the fluid channel.

A mechanical amplifier may in embodiments be of the type disclosed in US61/345,625.

Additionally the exemplary embodiment may also include a temperature compensation element 92 and a trimming device 93.

Figure 14 is an exemplary embodiment of a low pressure valve with geometry similar to that of

Figure 13.

In this example a cavity 99 has been made in the rigid, hard conduit 90. This cavity encloses a housing 98, which is anchored to the chassis of the ventilator. The actuator element 96 is located in the cavity. An advantage of this design of the valve device is that structure portion enclosed in conduit 100 may be removed from the actuator portion. A resilient element 97 combined with an axis element 95 ensures that the actuator movement is transmitted to the valve device, and that the units may be docked.

The lower drawing illustrates a cross-section of the valve device along the flow channel.

Figures 15 and 16, both are exemplary embodiments of a low pressure valve with the basic design similar to what has been aforementioned e.g. in Fig. 6 to 8. Fig 15 shows a valve device having added ultrasound transceiver elements 190 and 191. The ultrasound transceiver element 190 is fixed in the valve device inlet 70 by the supporting elements 192. The second ultrasound transceiver element 191 is positioned downstream of the first transceiver element 190, e.g. at a body in the flow channel. In this manner, ultrasonic Doppler measurements may provide a precise measure of the fluid flowing in the conduit 750. A compact and cost effective assembly is provided. The flow measured by means of the ultrasound transducers 190, 191 may be used in a control loop to control the actuator of the valve.

Figure 16 is an exemplary embodiment where substantially longitudinal grooves 210 and 211 on the outside of the flexible segments of the flexible conduit have been added to decrease the axial compression resistance of the segments.

Figure 17 is an exemplary embodiment of a low pressure valve with a rigid, hard conduit 450 surrounding a flexible conduit 451 in a coaxially arranged configuration. When ring 452 is moved a distance 453 the valve device is closed as illustrated to the right in Fig. 17.

Figure 18 is an exemplary embodiment of a low pressure valve having an advantageous configuration. The low pressure valve is a flexible conduit surrounding a rotationally symmetric body 186. Here the flexible segments 183 and 185 are only used to allow a movement of the flexible segment 184, being the valve part. The valve part moves against a symmetrical body 186. The valve part has a groove aimed to be fitted with a ring formed plate (not shown). The ring formed plate is connected to an actuator (not shown). The motion of the actuator moves the ring formed plate in an axial direction towards or from the rotationally symmetrical body 186. The rotationally symmetrical body 186 is fixed to a stiff inlet ring 182. The inlet ring 182 and an outlet ring 187, also made of a stiff material, are both fixed to a chassis or holder. By moving the ring formed plate in an axial direction towards the inlet ring 182 or outlet ring 187, the flexible segment 184, i.e. the valve part may close or open the valve device.

Figure 19 is an exemplary embodiment of a low pressure valve with a flexible conduit surrounding a rotationally symmetrical body 694, 698 and 695. The inner symmetrical part has a flexible section 698. On the outlet side of the valve, a gas permeable plate 699 is fixed to an inner plate 695 and outer ring 693. On the inlet side of the valve, a gas permeable plate 690 is fixed to the inlet tube 691 which holds or supports the rotationally symmetrical part 694. An axial movement 291 causes the flexible segment 696 and the flexible section 698 to be compressed or decompressed. The tube flexible segment 697 allows the movement while tube parts 691 and 692 still being fixed. When flexible sections 696 and 698 are decompressed the valve is opened and a flow 290 can pass through the valve. If the valve is used as a valve with output to an ambient environment, parts 692 and 697 can be omitted. The flexible parts 696, 698 and 697 have round shapes in this example, but other geometries are also possible, i.e. as the flexible segment aforementioned in this description.

An advantageous design of a valve device according to one embodiment of the invention may be obtained by means of a soft conduit, fastened at the ends, manufactured of e.g. silicone rubber, with flexible segments as shown in Figures 1 or 2 and via a movable ring exposes the flexible conduit to an axial movement between the ends so that the flexible elements are affected. Figs. 5, 6, 18 and 19 illustrates such examples. The Figure 5 and 6 show two variations of a valve device in each in two different states. The left illustrations show the valve devices in the open state and in the right in closed state. There is a rotationally symmetrical hard body 51 , 61 centered inside the flexible conduit, which has been aerodynamically designed to minimize the flow resistance in the valve device. Body 51 , 61 is fastened to the fastening rings 52, 62 and 53, 63 by supporting elements, not shown in the figures.

When the valve device is in the open state, as shown in the left illustration, Fig. 5 and 6, the inside of the flexible conduit is virtually completely straight and even. This in combination with the design of the center body 51 , 61 causes very low flow resistance in the valve device. The valve device is closed by moving ring 54,64 a distance 55, 65 in an axial direction towards fastening ring 52, 62. This causes the flexible segment 50, 60 to angulate or protruding towards the body 51 , 61 and ultimately be pressed against the body 51 , 61.

The valve is opened by moving ring 54, 64 a distance 55, 65 in an axial direction towards fastening ring 53, 63. This causes the flexible segment 50, 60 to straightening up from the body 51 , 61.

In closed position the flow profile is no longer at optimum, but this has no importance, as there is no flow passing through the valve device in the closed position.

The ring may also be positioned in-between the closed and open position. In this case the valve device acts as a proportional valve. The flexible conduit segment 50, 60 may be made lighter by removing material from the outside to reduce outer dimensions and to improve response times of the system. Naturally, the device will also functions with a flexible segment according to Figure 1. The response time may also be improved by removing material from the lower flexible conduit segment in Figs. 5 and 6.

In Fig. 20 a method is illustrated. The method is a method 1000 for controlling a flow through at least one fluid passage. The method comprises, axially compressing or decompressing 1010 at least two flexible segments 30, 31 of a valve 1 , 2, 3 by means of at least one actuator unit. The method further comprises compressing at least one of said flexible elements 30, 31 and expanding 1020 at least one second flexible element 30, 31. In this manner at least one other of said flexible elements is protruding substantially radially towards or straightening up from a corresponding valve seat 330, 331 for controlling 1030 said flow through said fluid passage.

In the method, the valve is preferably one of the afore descried valves. The method may comprise measuring a flow by means of a flow meter integrated into said valve. The flow may be controlled based on at least a flow signal measured by said flow meter.

In this manner, the method provides for generating a proportionally controllable substantially non-turbulent flow of one or more fluids through one or more flow channels of said valve.

The flow may be controlled by a single actuator.

The method may comprise alternately controlling two flow channels by said actuation.

The method may comprise simultaneously performing said controlling of two flow channels.

The movement of said flexible elements for controlling said flow may comprise pivoting said flexible element in a substantially radially direction of said valve towards said valve seat wen compressing said flexible element. The actuating may occur in an axially direction..

Various types of valves are described above. The valves may be provided using principles according to the present invention, e.g. expiratory valves, patient pressure relief valves, mixer valves and flow valves in low pressure systems, two way valves and multipath selector valves.

The present invention has been described above with reference to specific embodiments.

However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above, performing the method by hardware or software, may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.

Claims

A valve (1 , 2, 3) comprising:

- at least two flexible segments, (30, 31) each having at least one flexible zone (320, 321);

- at least one valve seat (330, 331), corresponding to at least one of said flexible segments (30, 31), that is positioned either outside and/or inside of said at least two flexible segments (30, 31);

- at least one flow channel (350, 351 , 352, 353, 354, 750) located between said flexible segments (30, 31) and said valve seat (330, 331) for passage of a fluid;

- at least one actuator unit arranged to axially compress or decompress said flexible segments (30, 31) for control of a flow of said fluid through said flow channel, wherein one of said flexible segments (30, 31) by a motion of said actuator unit is either protruded radially towards or straightened up from said valve seat (330, 331) and wherein at least one other of said flexible segments (30, 31) is positioned to allow said axial movement.

The valve according to claim 1 , wherein each flexible segment (30, 311) having at least one flexible zone (320, 321) being an articulation arranged to angle said flexible segments (30, 31) substantially radially.

The valve according to claim 1 or 2, wherein at least one of said flexible segments (30, 31) has a touching area configured to, after said flexible segment (30, 31) is protruded radially a defined distance, touch a valve seat (330, 331) with said touching area.

The valve according to claim 3, wherein said touching area includes said flexible zone (320, 321).

The valve according to any of claims 1-4, wherein at least one of said flexible segments (30, 31) having a zone configured so that a sealing effect occurs when it touches said valve seat (330, 331).

The valve according to any of claims 1-5, wherein said flexible segments (30, 31) and said valve seats (330, 331) are arranged and positioned relative each other so that said flexible segments (30, 31) are arranged in at least one position that allows a flow being substantially without turbulence through said flow channel (350, 351 , 352, 353, 354) of said valve.

7. The valve according to any of claims 1 -6, wherein said flexible segments (30, 31 ) are configured to in at least one position have a side with even characteristic located on at least a flow side of said channel.

8. The valve according to any of claims 1 -7, wherein said flexible segments are an

integrated part.

9. The valve according to any of claims 1 -8, wherein said valve is configured to be used with medical ventilators.

10. The valve according to any of claims 1 -9, wherein said axial motion is along or against the direction of said flow.

11. The valve according to any of claims 1-10, wherein said radially motion occurs

substantially vertical relative the direction of said flow.

12. The valve according to any of claims 1-11 , wherein said valve seat (330, 331 ) is a

rotationally symmetric circular wall located in the center of at least one of said flexible segments (30, 31).

13. The valve according to any of claims 1-11 , wherein said valve seat (330, 331 ) has a rotationally symmetric conical profile and is located in the center of at least one of said flexible segments (30, 31) downstream.

14. The valve according to any of claims 1-11 , wherein said valve seat (330, 331) is a

rotationally symmetric circular wall that is an inside of a conduit, positioned around at least one of said flexible segments(30, 31).

15. The valve according to any of claims 1-14, wherein the construction material of said flexible segments (30, 31) and said valve seat (330, 331) are autoclavable.

16. The valve according to any of claims 1-14, wherein said construction material of said flexible segments (30, 31) and said valve seats (330, 331) are disposable

17. The valve according to any of claims 1-16, wherein said actuator unit is at least one piezoelectric actuator.

18. The valve according to any of claims 1-17, wherein said actuator unit is arranged

without contact to the flow channel.

19. The valve according to any of claims 1-18, wherein at least two ultrasounds transceivers (191 , 192) are located along, at least one of, said flow channels to measure said flow of a fluid through said channel.

20. The valve according to any of claims 1-18, wherein substantially longitudinal grooves (210, 211) are arranged within the outside of said flexible segments.

21. The valve according to any of claims 1 -20, wherein the flexible segments (30, 31 ) have a round shape when compressed.

22. The valve according to any of claims 1 -21 , wherein said valve seat is a flexible section (198) connected to said actuator unit; and whereby said motion of said actuator unit, said flexible section (198) is compressed simultaneously as one of said flexible segments (196), whereby said flexible section and said flexible segment are protruded towards each other to close said flow through said channel.

23. A method (1000) for controlling a flow through at least one fluid passage, wherein the method comprises, axially compressing or decompressing (1010) at least two flexible segments (30, 31) of a valve (1 , 2, 3) by means of at least one actuator unit,, comprising compressing at least one of said flexible elements (30, 31) and expanding (1020) at least one second flexible element (30, 31) and whereby said at least one other of said flexible elements protruding substantially radially towards or straightening up from a

corresponding valve seat (330, 331) for controlling (1030) said flow through said fluid passage.

24. The method of claim 24, wherein said method comprises

providing a valve according any of claims 1-22 comprising said actuator unit, said flexible elements, and said valve seat.

25. The method of claim 23 or 24, wherein said method comprises measuring a flow by means of a flow meter integrated into said valve.

26. The method of claim 25, wherein said method comprises controlling said flow based on at least a flow signal measured by said flow meter.

27. The method of any of claims 23-26, comprising generating a proportionally controllable substantially non-turbulent flow of one or more fluids through one or more flow channels of said valve.

28. The method of any of claims 23-27, wherein said flow is controlled by a single actuator.

29. The method of any of claims 23-28, comprising alternately controlling two flow channels by said actuation.

30. The method of any of claims 29, comprising simultaneously performing said controlling of two flow channels.

31. The method of any of claims 23-30, comprising pivoting said flexible element in a

substantially radially direction of said valve towards said valve seat wen compressing said flexible element.

32. The method of any of claims 23-31 , wherein said actuating is in an axially direction.