TECHNICAL FIELD OF THE INVENTION: The present invention relates to a valve arrangement according to the preamble of appended claim 1. The invention is in particular intended to be employed in connection with vessels used at sea, mainly sailboats which are equipped with an engine, for preventing the water of a cooling water circuit from entering the engine due to siphoning. The invention also relates to a method for controlling such a valve arrangement according to the preamble of appended claim 9.

TECHNICAL BACKGROUND: In engines on boats, seawater is usually used for cooling the engine. For this reason, such boats are normally designed with a water inlet to which a cooling water conduit is connected. The cooling water is by means of a water pump pumped to the engine of the boat, where it circulates in order to cool the engine. Subsequently, the cooling water is fed out of the boat via the exhaust-pipe of the boat.

Furthermore, certain kinds of boats, for example sailboats equipped with engines, are designed with an engine which is placed deep down in the boat, sometimes so deep down that the engine is placed essentially below the water line of the ambient seawater. This means that the water level in the engine will also be below the ambient water line. In such an arrangement, there is a risk of a siphoning effect in the cooling water system if the cooling water conduit is filled with water. This siphoning effect will, in turn, cause a risk of seawater flowing into the exhaust outlet of the engine via the cooling water conduit when the engine is not running. The water can eventually rise so high in the exhaust outlet of the engine that it leaks into the

cylinders of the engine, which in turn can cause disturbances in operation, and breakdown of the engine.

This is of course a problem in a boat with an engine placed low in the boat.

In order to solve this problem, it is previously known to use an arrangement with a vacuum valve which is arranged along the cooling water conduit, between the cooling water pump and the engine of the boat. The vacuum valve is arranged relatively high in the boat, at a safe height above the water line. Furthermore, the vacuum valve is arranged so that when the engine is turned off, it admits passage of air to that portion of the cooling water conduit which extends above the water line, and when the engine is running, seals the water conduit against entry of air.

Since air is led into the cooling water conduit when the engine is not running, this prevents the entire seawater conduit from becoming water filled. This in turn prevents the siphoning effect from arising, which in turn obviates the risk of the engine being filled with water.

A known kind of vacuum valve is controlled by the water pressure in the cooling water conduit, and comprises a membrane of for example rubber, which is arranged to seal a valve seat. During operation of the engine, there is a ceratin overpressure in the conduit, since the cooling water pump is operative. This overpressure affects the membrane to be pressed against the valve seat, thus sealing the valve and blocking the cooling water conduit from entry of air. When the engine is turned off, this causes a slight underpressure, since the water column in the conduit from the vacuum valve to the water line strives to be evacuated.

This, in turn, affects the membrane so that it is released from the valve seat, thus opening the valve so that air can flow into the cooling water conduit. In this way, the siphoning effect is prevented from arising.

Although this known device in principle functions satisfactorily, it however has certain drawbacks concerning its function. First of all, there is a risk that the valve won't close completely, i.e. that the membrane does not seal tightly against the valve seat when the engine is started. This is mainly due to the fact that salt deposits can gather on the valve seat or on the membrane. When operating the engine, this results in a small water leakage from the cooling water conduit via the valve and into the boat. This is, particularly in connection with modern boats, a problem, since such boats often have a relatively small keelson for gathering water leakage.

Another problem in connection with the above-mentioned known valve is that there is a risk of the valve not opening when the engine is turned off. This situation can be caused by the membrane sticking to the valve seat while the underpressure in the conduit is not able to release the membrane. A consequence of this could be that the engine is filled with water by cooling water being led into the engine by the siphoning effect, as has been explained above. This can of course lead to a breakdown of the engine.

SUMMARY OF THE INVENTION: The object of the present invention is to obviate the above-mentioned disadvantages and to provide an improved valve arrangement, in particular in a cooling water circuit in a boat equipped with an engine, in order to eliminate the risk of the engine being filled with water due to the siphoning effect. This object is achieved by means of a valve arrangement, the characteristics of which will become apparent from appended claim 1. The object is also achieved by means of a method, the characteristics of which will become apparent from appended claim 9.

The invention is intended to eliminate the siphoning effect in an engine which, at least in part, is arranged below the water line of ambient water, and comprises a first conduit and a pump for feeding water to said engine through the conduit, with at least a certain portion of the conduit having an extension above the water line, and a valve arrangement for alternatingly sealing and opening of said portion. The invention is characterized in that the valve arrangement is connected to a canal for feeding of a pressurized medium, with the function of the valve arrangement being controlled depending on the pressure in said canal. Preferably, an existing oil pressure in (or in connection to) the engine is utilized in connection with the engine, in order to control the function of the invention. The valve arrangement will block the cooling water conduit from entry of air when the engine is operating, and admit air into the cooling water conduit when the engine is turned off. This eliminates siphoning effect in an efficient manner.

Additional advantageous embodiments of the invention will become apparent from the appended dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS: The invention will in the following be explained in more detail, with reference to an example of a preferred embodiment and the appended drawings in which: Fig. 1 in principle shows a valve arrangement according to the invention, and how the arrangement can be used in connection with an engine in a boat, and Fig. 2 is a cross-sectional view along the line A-A of Fig. 1, and shows a valve arrangement to be used in connection with the invention, and

Fig. 3 is a cross-sectional view through a water filter intended to be used in connection with the invention.

PREFERRED EMBODIMENT: The invention is in particular, but not exclusively, suitable for use in connection with boats powered by engines, and is primarily intended to prevent the siphoning effect from causing cooling water to enter an engine which is not operating. Fig. 1 shows the principle design of the invention, which in a preferred embodiment is arranged in connection to an engine 1, which in turn is arranged in the engine room in a power boat 2. The drawing shows the rear part of the power boat 2. The engine 1 can be either a gasoline or diesel engine, and is, in a conventional manner, equipped with a propeller shaft 3 which supports a propeller 4.

The power boat 2 is of the kind where the engine 1 is arranged relatively low, to be more exact in such a manner that the engine 1 is essentially arranged below the water line 5, i.e. the water line of the water which surrounds the boat 2.

In the bottom 6 of the boat 2, there is arranged a water inlet which comprises an aperture 8, to which there is connected a hose conduit 9. The purpose of this arrangement is to lead seawater into the engine 1 in order to cool it.

The hose conduit 9 is connected to a seawater filter 10 which is arranged for cleaning incoming seawater. The cleaning function of the filter 10 is of a known kind, and is thus not described in detail here. At least a certain portion 9 of the hose conduit 9 is arranged so that it has its extension above the water line 5. The hose conduit 9 and the filter 10 are arranged in such a manner that the filter 10 is positioned at a certain distance above the

water line 5, preferably at least 10-20 cm above the water line 5.

The filter 10 is placed on the suction side of a water pump 11, which preferably is arranged in connection to the engine 1. Alternatively, the pump 11 can be an integrated part of the engine 1. The pump 11 is so arranged that it during operation of the engine 1 pumps seawater through the hose conduit 9 via the filter 10 into the engine 1 where the seawater is used to cool the engine 1. For this purpose, the engine 1 is provided with a heat exchanger 12, which in a known manner is connected to a cooling jacket 13, using which the engine 1 can be cooled. The cooling water is led out through the heat exchanger 12, and following this, via a short hose 14 out into an exhaust gas outlet 15 of the engine 1. In the exhaust gas outlet 15, the outgoing cooling water is mixed with the exhaust gases of the engine 1.

The exhaust gas outlet 15 is connected to a muffler 16, which is positioned close to the bottom 6 of the boat 2. A further hose conduit 17 extends from the muffler 16 to an outlet 18 through which the cooling water is led out together with the exhaust gas of the engine. In order to prevent water from entering via the outlet 18, the hose conduit 17 is preferably given a bend which extends a certain distance above the water line 5.

When the engine 1 is running, cooling water is fed out through the exhaust gas outlet 15 together with the exhaust gases. When the engine 1 is turned off, a siphoning effect can arise if the hose conduit 9 is water filled at this stage, as mentioned initially. This causes water to be led into the exhaust gas outlet 15, and successively raises the water level in the exhaust gas outlet 15. Finally, the water level can become so high that water enters the

cylinders of the engine 1 via its exhaust gas outlets. The purpose of the invention is thus to eliminate the risk of such a siphoning effect arising.

The filter 10 is normally sealed from air and water, i.e.

during operation of the pump 11, no water or air will enter or exit from the filter 10 except for the cooling water which is taken into the filter 10 via the hose conduit 9.

The filter 10 is however given an aperture 12 which connects the raised portion 9 of the hose conduit 9 to a further conduit 19. This conduit 19 constitutes an airing conduit, by means of which said portion 9 can be connected to the ambient atmosphere so that air can be let into the hose conduit 9 in case of certain conditions, as will be explained below.

One end of the airing conduit 19 is thus connected to the filter 10, while its other end is connected to a special valve arrangement 20, which in turn is arranged at the engine 1. To be more precise, the valve arrangement 20 is so arranged that it connects to a canal inside the engine 1 for feeding oil under pressure, as will be described in detail below. The purpose of the valve arrangement 20 is for it to be affected by the oil pressure in said canal, so that it can be switched into one of two positions. Either the airing conduit 19 is sealed, so that no air is taken in, or the airing conduit 19 is opened to admit air, which in turn causes air to be let into the hose conduit 9 via the opening 12.

The valve arrangement 20 will now be described in detail with reference to Fig. 2 which is a cross-sectional view along the line A-A of Fig. 1. The valve arrangement 20 is designed around a valve housing 21, which is essentially bowl-shaped, and which comprises a protruding portion 22 which serves as an attachment in a corresponding recess 23

in the wall of the engine 1. The valve housing 21 can thus be attached to the engine 1, which is preferably done by providing the protruding portion 22 with external threads which cooperate with internal threads in the recess 23.

Furthermore, the inside of the recess 23 is connected to a drilled canal 24 in the engine 1, allowing oil to be transported through the engine 1 to lubricate the engine.

In more detail, the canal 24 is connected to an existing (not shown) oil pump which is used to pump oil in the engine 1. According to known technology, oil is pumped from an oil trough and out into various lubrication points via a canal system in the engine 1, with the canal system not shown in more detail.

The protruding portion 22 is provided with an internal valve canal 25 which leads up to a cylindrically shaped area 26 which houses a moving piston 27. The piston 27 is shaped with a first cylindrical portion 28, and a second cylindrical portion 29, with the first portion 28 having essentially the same outer diameter as the inner diameter of the valve housing 21, and the second portion 21 having a slightly smaller outer diameter. Due to this arrangement, oil which is under pressure in the oil canal 24 can flow into the cylinder area 26 and cause the piston 27 to move in a direction away from the valve canal 25 (i.e. to the right in Fig. 2).

In order to achieve a good sealing, a first piston portion 27 is preferably provided with a peripheral recess 30 which supports a sealing ring 31 which seals against the inside of the cylinder area 26.

At the end of the other piston portion 29, there is arranged an essentially disc-shaped membrane 32 which preferably is manufactured from an elastic material, for

example rubber. The membrane 32 is attached to the piston 27 by being shaped with a cylindrical portion 33 with an internal edge 34 which fits into a recess 35 in the second piston portion 29. Furthermore, the perimeter of the membrane 32 is fixedly arranged at the valve housing 21 by the perimeter being so shaped that it attaches into a further recess 36 in the end portion of the valve housing 21.

When the piston 27 is influenced to be moved by the oil in the cylinder area 26, the membrane 32 will thus also be moved. The valve arrangement 20 is so shaped that the piston 27 in its influenced position (i.e. if it is moved by the oil pressure to the right in Fig. 2) causes the membrane 32 to move to a position where it is in sealing contact with the nozzle of a cylindrical piping 37. The piping 37 is fixedly arranged at the end of the airing conduit 19, which in turn leads up to the opening 12 (see Fig. 1).

The piping 37 is kept in position in relation to the valve housing 21 by means of an essentially bowl-shaped supporting element 38. The bottom side of the supporting element 38 is fixedly connected to the piping 37, and additionally has a casing surface so shaped that it can be snapped into a peripheral recess 39 on the outside of the valve housing 21. Furthermore, the supporting element 38 is provided with at least one aperture 40 through which air can pass to the piping 37 if the membrane 32 is not in contact with the piping 37.

Furthermore, the valve arrangement 20 comprises a spring 41 whose one end is arranged at the piston 27, and whose other end is in contact with a shoulder 42 or the like in the valve housing 21. The coil 42 is so arranged that it, in its normal condition, influences the piston 27 to move away

from the piping 37 (i.e. to the left in Fig. 2), which causes the membrane 32 to also be affected away from the piping 37.

The valve housing 21 is preferably provided with a stop ring 43, the purpose of which is to define a stop which prevents the piston 27 from moving too far into the cylinder space 26.

The function of the valve arrangement 20 will now be described with reference to Figs. 1 and 2. When the engine 1 is started, the oil pump (not shown) of the engine 1 will also be activated. This causes a certain overpressure in the oil canal 24, which will cause oil to be pressed out into the cylinder space 26 of the valve housing 21. This will cause the piston 27 to be moved, whereby the membrane 32 is pressed into contact with the piping 37. In this manner, the airing conduit 19 is sealed so that air cannot enter in through the opening 12 and into the hose conduit 9. During operation of the engine 1, the water pump 11 will also be activated, which will cause cooling water to be fed through the hose conduit 9 to the engine 1. This operation will continue as long as the engine 1 is running.

When the engine 1 is turned off, its oil pump will also be turned off, which will cause the oil pressure in the canal 24 to fall. By means of the coil 41, the piston 27 will then be moved away from the piping 37, so that the membrane 32 is no longer in contact with the opening of the piping 37. In this manner, the airing conduit 19 is opened so that air can enter into the portion 9 of the hose conduit 9 which extends above the water line 5, since the membrane 26 will then have been moved away from the piping 31. Due to this, the portion 9 of the hose conduit 9 which is above the water line 5 will be emptied of water, thus preventing

any siphoning effect from arising. This eliminates the risk of water entering the engine 1.

The airing conduit 19 is prevented from being filled with water during operation of the engine 1 by means of a special arrangement in connection to the filter 10. This arrangement is shown schematically in Fig. 3, which is a cross-sectional view through the filter 10. The filter 10 is designed around a bowl-shaped housing 44 which supports a filter insert 45. Cooling water is led via the hose conduit 9 (see Fig. 1) and into the filter 10 via an inlet 46. The cooling water is led through the filter insert 45, where it is filtered, and is subsequently led out of the filter 10 via an outlet 47. The path of the cooling water is schematically indicated with arrows in Fig. 3.

The filter 10 is covered by a lid 48, which is provided with the above-mentioned through-going hole 12, which connects the inner of the filter 10 with the airing conduit 19 as has been described above. Furthermore, the underside of the lid 48 is provided with a screening element in the form of a tube-like portion 49 which surrounds the hole 12.

In this manner, cooling water which enters is efficiently prevented from penetrating into the airing conduit 19 via the hole 12 during operation of the water pump 11.

The invention is not limited to the example of an embodiment described above and shown in the drawings, but can be varied within the scope of the appended claims.

In an alternative embodiment, the hose conduit 9 can be connected directly to the pump 10, i.e. without utilizing any intermediate water filter. In this case as well, the hose conduit 9 is arranged so that a certain portion of it extends above the water line 5. The airing conduit 19 is then attached directly to this portion. The function of

this embodiment otherwise corresponds to that described above.

In a further embodiment, the valve 20 can be arranged directly on the filter 10, i.e. without utilizing any intermediate airing conduit 10. In this case, the valve 20 is provided with oil under pressure from a separate oil conduit which extends from the oil gallery of the engine 1 to the valve 20. Furthermore the valve 20 in a possible embodiment can be connected directly to the hose conduit 9, i.e. without any intermediate airing conduit.

The invention can be used in different kinds of applications where there is a desire to prevent water from entering due to siphoning effect and where an oil pressure is utilized in order to control a valve arrangement of the above-mentioned kind. Apart from power boats, the invention can also be used in fixed installations, for example purifying plants and pump stations. That portion 9 of the hose conduit 9 which extends above the water line 5 is then connected to the valve arrangement 20, which in turn is controlled by a pressurized medium, for example oil.

Instead of connecting the valve arrangement 20 to an oil canal 18 in the engine 1, a separate oil pump or a servo pump can also be used to generate the necessary oil pressure.

Furthermore, it is not necessary for the hose conduit 9 to extend directly from the filter 10 to the oil pump 11. The hose conduit 9 can instead extend from the filter 10 and through a reversing gear of the engine 1, where the water can be utilized to cool oil, and subsequently to the oil pump 11.

Also, the valve 20 can in principle be controlled by any other pressurized medium than oil, for example pressurized air.

In an alternative embodiment, a solenoid can in principle also be used to control the valve 20. For marine applications, the valve should then be closed in case of power being supplied, and be open when the system is not powered, in which case the solenoid can be returned by means of a coil. A signal from the oil pressure guard can then be utilized in order to control the valve via a relay.