Mechanical breathing sensing device

Abstract

A mechanical breathing sensing device, comprising a diaphragm (200) supporting a valve actuating magnet (411) outside a valve chamber (421) and a movable valve seal magnet (415) within the valve chamber (421) and operatively connected to a valve seal (417) wherein movement of the valve seal (417) between a closed position and an open position is controllable by magnetic interaction between said valve actuating magnet (411) and said valve seal magnet (415).

Description

[0001] MECHANICAL BREATHING SENSING DEVICE

[0002] TECHNICAL FIELD

[0003] The invention relates to mechanical breathing sensing devices, in particular for diving equipment, and in particular preferably fully mechanical, i.e. not in need of any connected electronic component to fulfil its function, breathing sensing devices having magnetic valves in which the opening and closing of a valve seal on a valve port is controlled by a valve seal magnet within a valve chamber and an actuating magnet arranged outside the valve chamber.

[0004] BACKGROUND ART

[0005] In skin diving with dive tanks, so called SCUBA diving (Self Contained Underwater Breathing Apparatus), the diver is provided with air from pressure tanks that he carries with him during the dive. For obvious reasons it is extremely important that the diving takes place safely. Throughout the years, many appliances have been developed to prevent accidents in connection with diving. One example is the inflatable diving jacket carried by the diver, which helps him to control his buoyancy, and which is used in combination with weights in order to help the diver to descend. Examples of other appliances are tables and portable dive computers that help the divers to plan diving in order to avoid the bends or having to surface quickly e.g. because air is running out. Diving equipment itself has also developed and has been provided with devices that aim to prevent accidents.

[0006] One situation that quite frequently results in near-accidents and sometimes in drowning is when the diver for some reason is suffering from stress as he surfaces. Numerous safety devices in connection with diving equipment are previously known, which intend to give improvement in respect of the shortcomings described above, e.g. FR 2741853 EP 034569, US 4,176,418, US 5,746,543 and US 5,560,738 which all present some disadvantage / s.

[0007] There is a concept that provides an elegant conceptual solution, disclosed in WO2008143581 and W02007058615. Additionally, WO2011108985 discloses a breathing sensing device with a plurality of valves which control the flow though passages and chambers. The valves comprise conventional pistons and sealing rings which are cumbersome and introduce friction and hysteresis into the system. Thus, there is room for improvements that may increase safety even more and / or improve cost efficiency and / or improve reliability, etc.

[0008] US 10221958 relates to a magnetically toggled valve with a valve cavity with a valve seat which can be contacted by a toggle plunger to close the valve. Movement of the toggle plunger is controlled by magnetic force provided by an external actuating magnet.DISCLOSURE OF THE INVENTION

[0009] It is an object of the invention to provide fully mechanical breathing sensing devices according to claim 1 with a magnetic valve which operates with low friction and low hysteresis. Such devices are suitable for use with a diver’s breathing regulator and a personal buoyancy device to form a safety apparatus for divers.

[0010] BRIEF DESCRIPTION OF THE FIGURES

[0011] In the following the invention will be described with reference to the appended drawings, wherein:

[0012] Fig. 1 shows a schematic fluid pathway arrangement of a safety actuator for diving equipment including a fully mechanical breathing sensing device in accordance with the invention,

[0013] Fig. 2 presents a schematic cross-sectional view of a safety actuator showing different aspects of the safety actuator,

[0014] Fig. 3 shows the pressure inside the upper pressure chamber, the lower pressure chamber and the timer volume chamber of the safety actuator over time in a first scenario.

[0015] Fig. 4 shows the pressure inside the upper pressure chamber, the lower pressure chamber and the timer volume chamber over time in a second scenario.

[0016] Fig. 5a) is a schematic cross-section of a first embodiment of a magnetic valve according to the invention in a closed state,

[0017] Fig. 5b) is a schematic cross-section of a first embodiment of a magnetic valve according to the invention in an open state,

[0018] Fig. 6a) is a schematic cross-section of a second embodiment of a magnetic valve according to the invention in a closed state,

[0019] Fig. 6b) is a schematic cross-section of a second embodiment of a magnetic valve according to the invention in an open state,Fig 7a) is a schematic perspective view of the magnetic valve of figure 5a) in a closed state.

[0020] Fig 7b) is a schematic perspective view of the magnetic valve of figure 5b) in an open state.

[0021] DETAILED DESCRIPTION

[0022] The advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, that mainly are presented in relation to a safety actuator for diving equipment including a mechanically operated breathing sensing device, wherein Figs 2, 3 and 4 are known from WO2011108985, which herewith is introduced and included by way of reference. Further, the present description, and the examples contained therein, are provided for the purpose of describing and illustrating certain embodiments of the invention only and are not intended to limit the scope of the invention in any way.

[0023] Fig. 1 shows a schematic view of a fluid system in a safety actuator assembly for diving breathing equipment with a fully mechanically operated breathing sensing device (i.e. not in need of any connected electronic component to fulfil its breathing sensing function) in accordance with the invention, which aspects will hereinafter be described in more detail, after firstly describing details and functions of the prior art actuator assembly 8 shown in Fig 2, in order to improve clarity regarding functions of the safety actuator.

[0024] Hence, in Fig. 2 there is shown, in cross-section, a schematic view of a prior art embodiment of an actuator assembly 8 as shown in WO2011108985, wherein some basic functions are the same as for the actual invention, and which functions may be more easily understood by reference to Fig. 2.

[0025] Within the 80 housing there are arranged channels LI (shown as thick lines) connected to the supply pressure SP of gas, e.g. air, from the first stage (not shown) of a conventional diving regulator (not shown) connected to a supply, such as an air tank, of breathable gas, and channels 7 (shown as thin lines) connected to ambient pressure. These channels LI, 7 are interconnect via a number of mechanical valves arranged in the housing 80 to fulfill the functionality in accordance with the invention, as will be described in detail below.

[0026] Adjacent a first end of the actuator assembly 8 there is arranged a diaphragm 200, i.e. a taut flexible membrane, of an ON / OFF valve OV. This valve OV has to be subjected to apredetermined pressure, for example a pressure corresponding the water pressure at a suitable depth, e. 1 to 2 metres, to be automatically activated into the “on mode”. This can be achieved by means of the water pressure (H2O) acting on an outer side (i.e. the side facing the external environment) of diaphragm 200. Manual activation could be achieved by providing a button (not shown) which can be pressed by a user, and which acts on the outer side of the diaphragm. The other, internal, side of the diaphragm 200 is balanced by air chamber 201 that is able to be calibrated to the actual ambient air pressure (thereby allowing consistent operation independently of the prevailing atmospheric pressure at the surface of the water where the actuator device is being used) and subsequently is able to allow the diaphragm to move into the active state at the desired actuation pressure. Before applying system pressure SP (i.e. by connecting the actuator assembly 8 to the first stage of a diving regulator) air chamber 201 is open towards the atmosphere ATM via a valve 202 and channel 7, hereby being in connection with ambient air pressure. Once system pressure is applied (i.e. when the air tank is opened), air will flow through channel LI and said valve 202 is affected to move into a closed position, thereby closing the interface between the external environment and the chamber 201 underneath the diaphragm 200. The air chamber 201 is thus hermetically closed and calibrated to the actual ambient air pressure ATM.

[0027] Subsequently, when the device is immersed in water, and the water pressure acting on the diaphragm 200 exceeds a certain pressure which is predetermined by, amongst others, the volume of the air chamber 201 and the range of movement of a piston 208 fixedly attached to the diaphragm, which piston will move downwards into contact with a seal 220 and thereby open up a fluid connection to a hollow channel 230 within the piston 208 which leads to a restriction passage 212 leading to a timer volume 213, which restriction passage may be achieved by means of grooves (not shown) on the inner wall of the piston 208, above the inactive position of the seal of sealing body 240 within the hollow channel 230. Hence, when inactive (when the diaphragm 200 is in the neutral position) the sealing body 240 seals, but when active (diaphragm 200 and piston 208 moved downwards in the figure) air will pass by the body 240 at a rate limited by the restriction passage 212. The timer volume 213 will hereby slowly be filled which gradually builds up the pressure therein. The volume of the timer valve helps determine the time it takes for activation to occur and is preferably small in order to keep the device compact. The timer valve volume is preferably equal to or greater than 1 ml and less than or equal to 30 ml , for example 13 ml. The restriction passage 212 is preferably extremely narrow to allow the actuator body to be very compact. In other words, a very low flow rate of air through the restriction passage 212 should be allowed, to provide sufficient time for the small timer volume 213 to achieve the function of the timer volume 213, which is to open up the release valve (RV) 25 (described below) to, for example, inflate a diver’s buoyancy device (BD), when no breathing has occurred for a predetermined amountof time, thereby automatically bringing the diver to the surface. For example, with a timer valve volume of 13 ml as shown in figure 1, a flow corresponding to 0.5 ml per second at the actuation pressure needed in the timer volume the restriction passage 212 will give an predetermined actuation time of 26 seconds. Preferably the amount of time of the predetermined actuation time is between 25 and 40 seconds. In order to provide a compact unit, the timer volume 213 is positioned next to the on / off valve OV and the release valve (RV) 25 is positioned adjacent to the opposite end of the actuator body compared to the ON / OFF valve OV.

[0028] Between the release valve, RV, and the timer volume, TV, there is arranged the activity sensor valve, AV, which detects breathing of the user. This valve AV also comprises a diaphragm 100 having a piston 103 fixedly attached thereto. The piston 103 has a seal, for example an upper lip seal, arranged to seal against flow towards the timer volume TV. The piston valve of the AV is hollow, i.e. provides a central passage 111. On one side of the diaphragm 100 there is a pressure chamber 120 in contact with the system pressure line LI. Below, on the other side of diaphragm 100, there is a pressure chamber 121 providing a balancing pressure. The flow connection opening 153 between the upper chamber 120 and the system pressure LI is rather large, e.g. with a diameter of the order of 2 mm to allow substantially unrestricted flow there between. The balancing pressure in the lower chamber 121 is achieved by providing a flow restriction arrangement 130 with a restricted passage 143 between the system pressure LI and the lower pressure chamber 121. In one aspect the restriction passage 143 is combined with a kind of check valve functionality that is obtained by means of e.g. a lip seal 144, as shown in Fig. 2.

[0029] Thanks to this design the AV will empty the timer volume 213 in connection with the pressure drop which is caused by breathing, thereby resetting the timer after each breath. The pressure development inside the pressure chambers 120, 121 around the diaphragm 100 as well as within the TV chamber 213 will now be described with reference to the details of Fig.

[0030] 2 and the diagrams presented in Figs. 3 and 4.

[0031] In Figs. 3 and 4, graph A is the pressure inside upper pressure chamber 120 over time and graph B shows the pressure inside lower pressure chamber 121 over time. Graph C in Figs. 3 and 4 represent the pressure inside timer volume chamber 213 over time.

[0032] In brief, when breathing in the form of inhalation occurs (see time point a) in Fig. 3) the system pressure LI will suddenly drop and thereby simultaneously provide a pressure drop in the upper chamber 120 (see graph A in Figs. 3 and 4). However, the lower chamber 121 (see graph B in Figs. 3 and 4) will maintain a higher pressure for a while thanks to the restrictionpassage 143. Consequently, diaphragm 100 will move upwardly and thereby the piston 103 will move up from the seat 107, to interconnect the timer volume 213 with ambient pressure 7 (see time point b) in Fig. 3). When the system pressure slowly again increases, the opposite phenomenon will occur, i.e. that for a while lower pressure will occur in the lower chamber 121 thereby safeguarding closing of the piston 103 against the seat 107 (see time point c) in Fig. 3). Consequently, again the timer volume 213 will be closed and sealed to successively fill up pressure via flow through the restriction 212.

[0033] In Fig. 4, a scenario is illustrated where breathing has stopped (time point a), and pressure inside pressure chamber 213 is increasing (graph C) until a threshold value is reached whereby the release valve RV is opened leading to inflation of a buoyancy device (BD) that may save the life of a diver by bringing the diver to the surface, and simultaneously the pressure in volume chamber 213 is nullified (time point b).

[0034] Now returning to Fig. 1 there is schematically presented an outline of an actuator assembly 8 according to the invention showing the internal fluid pathways and valves which provide basically the same functions as presented in connection with Fig. 2, i.e. comprising the ON / OFF valve (OV), the timer volume (TV), activity sensor valve (AV) and release valve (RV) connected to each other in a similar manner regarding function as has previously been described in connection to Fig. 2.

[0035] In order to provide for easy understanding of basic functions the same reference numbers are used in Fig. 1 as for corresponding features of Fig 2. The main different aspect of the novel concept is the use of magnetic valves MV1 and MV2, in the activity sensor valve AV and the ON / OFF valve OV, respectively, which may provide significant advantages, e.g. enabling a much more compact design, since when using a magnetic valve MV1, MV2 in accordance with the invention the diameter of the diaphragms 100, 200 may be much smaller than that needed in the design shown in Fig. 2. Actual tests have shown that the diameter for diaphragms 100, 200 in a magnetic valve MV1, MV2 may be smaller than 30 mm, whereas diaphragms 100, 200 in a design shown in Fig 2. merely comprising mechanical means must be larger than 100 mm. Hence a reduction of the diameter of the diaphragm valves of 70% or more may be achieved.

[0036] Further, Fig. 1 shows some details that are not shown in Fig 2, i.e. a reset valve (RSV) and an Out of Air Guard, (OAG). The reset valve RSV is an optional precautionary feature enabling a user to deactivate the RV if it has been activated and the user does not desire the BD to be inflated. The Out of Air Guard, (OAG), is an additional safety feature that automatically will inflate the BD if the system pressure LI, which corresponds to the air cylinder pressure, fallsbelow a set pressure level, e.g. 5 bar (500 Kpa), which is an indication that the diver is at risk of running out of air.

[0037] Hence, also in Fig. 1 the on / off valve OV is arranged to activate the actuator assembly 8 (i.e. switch it into “on-mode”) when the actuator is moved to a position under water and the water pressure is applied via water line (WL) which is open to the surrounding water onto one side of the diaphragm 200. Manual actuation may also be made possible by means of suitably placed push button or the like which can move the diaphragm into an active state. On the other side of the diaphragm 200 there is a balancing air chamber 201 and a resilient force (e.g. a spring 221) calibrated to allow the diaphragm 200 to move into the active state at a predetermined outer pressure provided by the water line WL. The diaphragm 200 may also be held in position via a spring 221 which is pushing against the under portion of a valve actuating member 208 being fixedly attached to the diaphragm 2007

[0038] When the water pressure acting from WL on the diaphragm 200 exceeds a certain predetermined actuating pressure, a magnetic valve piston of MV1 fixedly attached to the diaphragm will move and thereby cause MV1 to open the connection between the system pressure LI and the TV. Thanks to the use of magnetic forces acting through the wall of the magnetic valve to open the connection there is no direct mechanical contact between the actuating and actuated parts of the valve and thus no need for any sliding mechanical means that need to be sealed (e.g. 208, 208A in Fig 2) with friction generating seals such as O-rings. The only passage between system pressure channel LI is the restriction passage 212 leading to the timer volume 213, which allows a very small, predetermined airflow to pass through and enter the TV chamber 213. The airflow of air passing the restriction valve 212 is influenced by its cross-sectional area and has a maximum width / diameter which, for example, is between 5 and 100 pm, preferably less than or equal to 50 pm. The restriction valve preferably comprises inlet and outlet filters 212a with openings which prevent particles which are greater than, for example, 1 / 3 of the diameter / width of the restriction valve from potentially blocking the restriction valve. The filtration size of the filters may for example be approximately 1.5 pm for a 5 pm diameter / width restriction filter to 34 pm for a 100 pm diameter / width restriction filter.

[0039] The timer volume 213 will slowly be filled with air and hereby a pressure will gradually be built up therein. Preferably, as described above, the restriction passage 212 is extremely small to allow the actuator body to be very compact. In other words, a very small flow rate of air through the restriction 212 should be allowed, to provide sufficient time for the chamber with a small volume 213 to achieve the function of the timer volume 213, which is to open the release valve RV when no breathing has occurred for a predetermined amount of time. Thetimer volume 213 is preferably positioned adjacent to the ON / OFF valve OV. The release valve RV is preferably positioned adjacent an opposite end of the actuator body compared to the ON / OFF valve OV.

[0040] The timer volume, TV, is connected to the activity sensor valve, AV, via channel L3. The activity sensor valve AV also comprises a diaphragm 100 (schematically shown in Fig 1, as two horizontal lines) having a magnetic valve piston MV2 fixedly attached thereto. Preferably this diaphragm is designed to move with little internal friction in order to avoid hysteresis. It may be formed from a substrate with front and rear major surfaces and is flat, concave, convex or conical and which is flexible and / or provided with corrugations which, like those in a loudspeaker cone, allow it to move in the direction of low pressure when subject to differential pressure across the major surfaces. It can be made of any suitable material, which preferably is water resistant. Suitable materials include, but are not limited to, films or sheets of metal, plastics (such as mylar, polypropylene, PET, etc.), rubbers, ceramics, and paper. Preferably the diaphragm has a width or diameter which is equal to or less than 50 mm and greater than or equal to 5 mm. It has a thickness which is equal to or less than 5 mm and equal to or greater than 0.01 mm. On one side of the diaphragm 100 there is a pressure chamber 120 in contact with the system pressure line LI. On the other side of diaphragm 100, there is pressure chamber 121 providing opposing balancing pressure. The flow connection opening 153 preferably a central opening, between the upper chamber 120 and the system pressure LI is preferably comparatively large (e.g. it has a diameter of, for example, from 1 mm to 10 mm, preferably below 5 mm) to allow substantially unrestricted flow there between. The balancing pressure in the lower chamber 121 is achieved by providing a flow restriction arrangement 130 with a restricted passage 143 between the system pressure LI and the lower pressure chamber 121. Preferably said flow passages 143, 153 have different cross sectional passage areas Ar, Af arranged to facilitate detection of a pressure drop due to breathing.

[0041] Preferably the ratio of cross-sectional passage area between the cross-sectional passage area Ar providing a restricted flow passage 143 to and / or from second pressure chamber 121 and the cross-sectional passage area Af providing a flow passage to and / or from the first pressure chamber 120 is in the range of 1 / 50 - 1 / 200. Said cross-sectional passage areas Ar, Af of said flow passages 143, 153 are preferably arranged to be constant through a pressure change in said system pressure LI. Thanks to the design according to the invention when a breath is taken a momentary pressure difference occurs between said first 120 and second 121 pressure chambers , as the system pressure LI will suddenly drop and thereby simultaneously provide a pressure drop in the upper chamber 120. However, the lower chamber 121 will maintain a higher pressure for a while thanks to the restriction passage 143. As a consequence, the diaphragm 100 will move whereby the thereto connected magnetic valve piston of MV2 will open up the connection to ambient pressure via L3 the timer volume 213 and a channel 7.In a scenario where a diver has not taken a breath for a predetermined length of time (preset by the timer valve TV), the volume inside TV chamber 213 will not be emptied by means of the AV valve, as described above, and the pressure inside TV chamber 213 will gradually increase. At a certain predetermined point, the increased pressure will lead to activation of the release valve RV and provide a connection via RV1 and L4 whereby pressurized air from the diver’s air tank will flow into a suitably connected buoyancy device (BD), e.g. it can inflate a diving jacket, thereby bringing the diver to the surface.

[0042] Below, a preferred design of magnetic valves for use in a safety actuator assembly 8 in accordance with the invention, will be described in more detail, by schematically showing in Figs. 5a) to 7b) essential principles of embodiments of such a magnetic valve MV2, used in the On Off valve OV shown in Fig 1. As already mentioned, the invention may provide much improved compactness compared to a valve using only directly acting mechanical operating means, e.g. as shown in Fig. 2 where moving parts are in direct contact with each other, thereby enabling a significant reduction of size to only 30% or less compared to a purely mechanical valve and without the use of any electrical components. Moreover, there are other advantages compared to a valve using only directly connected mechanical means, e.g. eliminating friction and hysteresis existing in valves using only directly connected mechanical means, e.g. needing a plurality of sliding seals, which may make specific operations / functions unreliable and subject to errors and wear. Hence, not only is more compactness achieved but also improved reliability. The absence of electrical components leads to simple operation without requiring any electrical power supply,

[0043] Fig. 5a), 6a) and 7a) show schematically the working principles of the magnetic actuator MV2 in the on-off valve OV in a non-activated state, i.e. no pressure is acting on the upper surface of the diaphragm 200, according to an embodiment of the present invention which may provide the above mentioned advantages. In this example of a magnetic actuator a diaphragm 200 is used to operate the magnetic valve MV2 but any other means for operating an actuating magnet may be used, for example a piston-like element sliding in a cylindrical cavity (however this would require a sealing ring and would have more friction and hysteresis than a diaphragm). The magnetic actuator in this ON / OFF valve OV uses a magnetic valve MV2 to open a pathway P2 for supplying system pressure air LI to the timer volume 213 (see Fig 1) when the actuating force on the diaphragm 200 exceeds a predetermined force. This force can be achieved by an operator pressing on the surface of an actuating button (not shown) or by water pressure acting on the diaphragm 200.The magnetic valve comprises an actuating magnet 411, which in this example is connected to, and operable by, the diaphragm 200 by means of an valve actuating member 208, wherein preferably the valve actuating member 208 includes an attachment member 203, which is integral with the diaphragm 200 and that enables positioning of the actuating magnet 411 at a distance X away from the surface of the diaphragm 200, e.g. X preferably being in the range of 0.2 mm to 10.0 mm (preferably from 1.0 to 5 mm) below the lower surface of the diaphragm 200, to arrange for having the actuating magnet 411 being movable within a guidance channel 427. Preferably this is partly achieved by using a very small magnet 411, e.g. having a volume less than 20 mm3, and / or by using a cylindrical shape (e.g. a diameter less than 10 mm, more preferred less than 7 mm, preferably 5 mm or less and a thick ness which is less than or equal to 5 mm, more preferably less than 4 mm and even more preferably 2 mm or less) such that the walls of the magnet may be appropriately adapted to a guidance channel 427 in the form of a bore. In all embodiments of the invention, the actuating magnet is preferably a rare earth magnet such as a neodymium magnet as these types of magnets have a large magnetic force to volume ratio. Preferably the actuating magnet is suspended from the diaphragm 200 so that it hangs freely and never comes in contact with the walls of the guidance channel, thereby preventing friction from arising and removing a potential source of hysteresis.

[0044] Further, there is shown a valve seal magnet 415 operatively connected to, e.g. attached to or close to, a valve seal 417 covering an inlet port / valve seat 419 of a valve chamber 421. In all embodiments of the invention, the valve seal magnet is preferably a rare earth magnet such as a neodymium magnet. The valve seal 417 may be a resilient pad or flap or the like which covers the opening in the inlet port 419 in the valve-closed position and thereby prevents the passage of fluid through the inlet port 419 to the outlet port 429 via the valve chamber 421. It is to be noted that the valve chamber 421 may be embodied in the form of an end of the channel L2, thereby existing as an integral part of the channel L2 and avoiding the need for any distinct outlet port 429. The valve seal magnet 415 and valve seal 417 are mounted on a resilient arm, or a rotatable arm 422 which is rotatable around a pivot axis 423 and biased by the arm itself being resilient or any suitable biasing means such as a spring 424, towards a valve closed position where the valve seal 417 covers and seals the inlet port 419. The diaphragm 200 is arranged to move the actuating magnet 411 in a first direction DI closer towards the valve seal magnet 415 when the diaphragm 200 is depressed, by the operator or by water pressure if the button is immersed in water. The valve seal magnet 415 and valve seal 417 are arranged to be able to move in a second direction D2 from the valve-closed position to a valve-open position. The second direction in this example of a magnetic valve is curved and is an arc of a circle C centred on the pivot axis 423. The radius of this circle is equal to the distance between the pivot axis 423 and centre of port 419. Preferably themagnets 411, 415 have their respective N / S poles positioned such that a repelling force will occur. This may be achieved by having their N / S poles in parallel planes with the same poles, i.e. north / north or south / south, positioned to face each other when in line, or (as shown in Fig 5a)-6b) by having the actuator magnet 411 with its poles in a vertical plane and the valve seal magnet 415 with its poles in a horizontal plane and then having the same poles closest to each other, e.g. S / S as shown in Figs 4a, 4b. Further, it is preferred to have the longitudinal axis of the first direction DI and the longitudinal axis of the second direction D2 to intersect at the position where the force between the magnets 411, 415 is at its highest when the diaphragm 200 is fully depressed. This ensures that the valve MV2 is fully open when the diaphragm 200 is fully depressed.

[0045] In the closed position the magnetic force interaction between the actuating magnet 411 and the valve seal magnet 415 is too low to cause any relative movement between these magnets. However, as the diaphragm is moved in the first direction DI under the influence of water pressure or an operator pushing on the button, the distance between the actuating magnet 411 and valve seal magnet 415 decreases and the interaction between their magnetic fields gives rise to a magnetic force which cause them to be repelled by each other. Lateral movement of the actuating magnet 411 away from the valve seal magnet 415 is constrained by the wall 425 of a guidance channel 427 so that substantially only the valve seal magnet 415 is moved laterally by the interaction between the magnetic fields. Once this magnetic force is sufficient to overcome the biasing force holding the valve seal 417 in place, the valve seal 417 will move out of contact with the inlet port 419, thereby opening the normally closed inlet port 419.

[0046] In fig. 5b), 6b) and 7b) the valve seal has been moved to the right due to the valve seal magnet 415 being repelled by the actuating magnet 411 as it moves closer to the valve seal magnet 415, thereby allowing the system pressure LI to pass to the valve chamber 421 via valve inlet port 419 and then onwards to an outlet port 429 that via a restriction passageway 212 leads to the timer volume 213 (see Fig 1). In this example of a magnetic actuator, there is no physical contact between the actuator magnet and the valve seal magnet so the moving parts of the valve sealing mechanism comprising the valve seal 417, rotatable arm 422 and any biasing means 424 are entirely contained within the valve chamber 421, thereby avoiding the need for any further sealing means. Thus, there are no seals needed between the moving parts except the valve seal 417 itself and there are no O-rings required in the magnetic actuator. This reduces the number of moving parts and seals, leading to reduced friction and reduced hysteresis.

[0047] The actuator magnet and the valve seal magnet never come into contact as they are separated by the wall of the valve chamber 421, this is a contactless magnetically operated valve.As already described above diaphragm 200 forms a flexible seal over an airtight actuator air chamber 201 which contains a known volume of air A at a starting atmospheric pressure ATM. This air is compressed by the diaphragm 200 when it is being depressed and resists the depressing of the diaphragm 200. The actuating pressure Pact that needs to be applied to the diaphragm 200 before the actuator magnet 411 is sufficiently close to the valve seal magnet 415 to open the valve seal 417 can be set by appropriate choice of the volume of air in the actuator air chamber 427 and the desired distance Y (preferably the distance Y is kept as small as possible to minimize the size of the magnet actuator, and preferably should be less than or equal to 3 mm, more preferably less than or equal to 2.5 millimeters, even more preferably less than or equal to 2.0 mm, yet more preferably less than or equal to 1.5 mm, most preferably less than or equal to 1.0 mm, and greater than or equal to 0.4 mm) that the actuator magnet must move in order to act on the valve magnet 415 to move the valve seal 417 off the inlet port 419. Preferably the pressure is set to correspond to a depth of water which is sufficiently high enough to prevent accidental activation of the ON / OFF switch and sufficiently low enough that it activates the ON / OFF switch once a diver descends below the water surface. The ON / OFF switch remains activated as long as the diaphragm 200 is depressed - either by the user or by the water pressure. A suitable pressure preferably corresponds to a depth between 1.0 and 2.0 metres of water (approximately 10-20 Kpa), more preferably to a depth between 1.25 and 1.75 m (approximately 12.5 Kpa and 17.5 Kpa) and most preferably between 1.4 and 1.6 metres (approximately 14.0 Kpa to 16.0 KPa), for example 1.5 metres (15 Kpa).

[0048] In the second embodiment of a magnetic valve shown schematically in figures 7a) and 7b), the valve seal magnet 415 and valve seal 417 may be arranged to move in a substantially straight line D2 so that the second direction may be a substantially straight line, with a longitudinal axis which optionally is substantially orthogonal to the first direction, and which is in a direction away from the actuating magnet 411.

[0049] In the above examples of a magnetic actuator a diaphragm is used to operate the magnetic valve in order to provide automatic actuation when the device reaches a predetermined water depth, but if this automatic operation is not required then any other moving means for moving an actuating magnet may be used, for example a simple push button or pull toggle with releasable locking means to hold the moving means into the on or off / open or closed positions.

[0050] While the magnetic valve has been illustrated with examples in which the valve seal is arranged to seal the inlet port 419 to a valve chamber, it is possible for the valve seal to bearranged to seal the outlet port 429 instead or, if required, valve seals can be provided on both the inlet port 419 and the outlet port 429.

[0051] While the magnetic valve has been illustrated with examples in which the valve seal is biased into the port-closed position and movement to the port-open position is achieved by movement of the actuating magnet towards the valve magnet, it is also possible to arrange for the valve sela to be held in the port-closed position by the proximity of the actuating magnet to the valve magnet, and the valve seal to be moved to the port-open position when the actuating magnet is moved away from the valve magnet.

[0052] Preferably all magnets used in the invention are neodymium magnets.

[0053] It is evident for the skilled person that the functionality that has been described above in relation to the restriction arrangement 130 may easily be achieved in various manners without as many details as has been described above. In an extreme embodiment all of it may be included in one single unit just presenting a desired fixed restriction passage 143 in combination with the kind of check valve functionality that is obtained by means of the lip seal 144. Accordingly, many variations may be made to the exact design of this arrangement 130.

[0054] The function during normal use is such that when the diver breathes the above-described small pressure drops will occur in the inlet line Lib. This pressure drop will immediately be communicated to the upper pressure chamber 120. However, the lower pressure chamber 121 will not instantly be provided with the same pressure due to the restricted passage 143 that connects inlet line Lib with said pressure chamber 121. Accordingly, there will, for a short time interval, (preferably arranged to be about 20-50 ms) be created a pressure difference over the membrane 100, which in turn will cause the membrane 100 to flex in the direction where the lowest pressure resides. Hence the membrane 100 will move upwardly into the upper chamber 120 and thereby move the piston 103. Thereby the timer release activation will be obtained as described above and the actuator reset.

[0055] The mechanical breathing sensing device operates purely mechanically and does not require any electronic or electrical components to actuate any of its functions. Optionally, to provide further, non-essential functions, it may be provided with electronic components such as sensors, at least one digital processer, software and memory and optionally transmitting and receiving capability which are combined to form an electronic monitoring device which can be used to monitor use of the device and / or record usage of the device and / or communicate use of the device to third parties.

Claims

CLAIMS1. Mechanical breathing sensing device comprising at least one of:an on / off valve;a buoyancy device inflation valve anda low system pressure valve ,characterized in that at least one of said valves is a magnetic valve (MV1, MV2, 401) controlling the flow of a fluid, comprising a valve chamber (421) with:an inlet port (419) for receiving a fluid;an outlet port (429) for outputting the fluid; andat least one valve seal (417) movable between a port-closed position for sealing at least one of the ports (419, 429) and a port-open position for opening at least one of the ports (419, 429),further comprising- a valve actuating magnet (411) arranged outside said valve chamber (421) wherein movement of the valve seal (417) between a port-closed position to a port-open position is controllable by said valve actuating magnet (411) characterized in that a movable valve seal magnet (415) is provided within the valve chamber (421) and operatively connected to said valve seal (417) wherein movement of the valve seal (417) between a port-closed position to a port-open position is controllable by magnetic interaction between said valve actuating magnet (411) and said valve seal magnet (415).

2. Mechanical breathing sensing device according to claim 1, characterized in that said valve actuating magnet (411) is movable within a guidance channel (427) that is hermetically sealed from said valve chamber (421) and that at least one end of said guidance channel (427) is positioned adjacent said valve chamber (421).

3. Mechanical breathing sensing device according to claim 1 or 2, characterized in that said magnetic interaction is provided by means of repelling forces between said actuating magnet (411) and said valve magnet (415), or that said magnetic interaction is provided by means of attracting forces between said actuating magnet (411) and said valve magnet (415).

4. Mechanical breathing sensing device according to claim 3, characterized in that the movement of said valve magnet (415) occurs laterally compared to the movement of said actuating magnet (411).

5. Mechanical breathing sensing device according to any of the previous claims characterized in that the valve seal (417) and valve seal magnet ( 15) are arranged on a rotatable arm (421) contained within the valve chamber (421).

6. Mechanical breathing sensing device according to any of the previous claims characterized in that the at least one valve seal (417) is biased into a port-closed position by biasing means or by magnetic interaction between said actuating magnet (411) and said valve seal magnet (415).

7. Mechanical breathing sensing device according to any of claims 1 to 5 characterized in that the at least one valve seal (417) is biased into a port-open position by biasing means or by magnetic interaction between said actuating magnet (411) and said valve seal magnet (415).

8. Mechanical breathing sensing device according to any of the previous claims characterized in that at least one of said actuating magnet (411) and said valve seal magnet (415) is a neodymium magnet.

9. Mechanical breathing sensing device according to any of the previous claims characterized in that said actuating magnet (411) and said valve seal magnet (415) are arranged to repel each other in the port-open position or to repel each other in the port- closed position.

10. Mechanical breathing sensing device according to any of the previous claims characterized in that said actuating magnet is connected to a diaphragm (200).

11. Mechanical breathing sensing device according to any of the previous claims characterized in that it is adapted to sense breathing mechanically without the use of any electrical or electronic components.

12. Mechanical breathing sensing device according to any of the previous claims characterized in that it comprises an electronic monitoring device which can be used to monitor use of the device and / or record usage of the device.

13. Mechanical breathing sensing device, according to any of the previous claims comprising a diaphragm (100) having a first pressure chamber (120) on one side and a second pressure chamber (121) on a second side, wherein said first and second pressure chambers (120, 121) are connected to a system pressure (LI) by means of flow passages (143, 153) having different cross-sectional passage areas (Ar, Af) arranged to facilitate detection of a pressure drop due to breathing.

14. Diving equipment including a mechanical breathing sensing device according to any of the previous claims.

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