EP0628476A1

EP0628476A1 - Pressure sensor combination for a vessel and valve with valve housing, sensor housing and basic housing thereof

Info

Publication number: EP0628476A1
Application number: EP94201499A
Authority: EP
Inventors: Joost Sijbesma
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-26
Filing date: 1994-05-26
Publication date: 1994-12-14
Anticipated expiration: 2014-05-26
Also published as: DE69409036D1; DE69409036T2; EP0628476B1; NL9300897A

Abstract

The invention relates to a pressure sensor combination suitable for being mounted in the outer wall of a vessel. This allows a water pressure-sensitive element of the pressure sensor combination to be in contact with the ambient water and to determine the water pressure at that location. On the basis of the water pressure, the draft and the weight of the load of a vessel can be determined. The pressure sensor combination comprises a movable valve capable of at least partly releasing a passage from the ambient water to the pressure-sensitive element and closing same to prevent damage to the pressure-sensitive element.

Description

The invention relates to a pressure sensor combination suitable for being mounted in the outer wall of a vessel permitting a water pressure-sensitive element of the pressure sensor combination to be in contact with the ambient water. The invention also relates to a valve housing with a valve, sensor housing and basic housing of this pressure sensor combination.
Such pressure sensor combinations are known from Dutch patent application No. 9001376 and are commonly used for determining the draft of a vessel and, accordingly, the weight of the load of the vessel. For each vessel there is a connection between the draft of the vessel and the corresponding water displacement, recorded in the Netherlands in a so-called certificate of tonnage by the national ship measurement service. According to Archimedes' principle, this water displacement is directly related to the weight of the ship and hence also to the load of the ship.
A pressure sensor combination mounted at a known position in the wall of a vessel measures the water pressure adjacent to the wall of the ship. In principle, this water pressure is directly proportional to the height difference between the water surface and the pressure-sensitive element of the pressure sensor combination. When this height difference is determined by means of the pressure sensor combination, the draft of the vessel is known, enabling determination of the weight of the load.
Preferably, the pressure sensor combination is connected to an apparatus to which output signals from one or more pressure sensor combinations, which are a measure for the above-mentioned water pressure, are fed. On the basis of these output signals, the apparatus determines the weight of the load, which weight may subsequently be directly shown on a display. The advantage is that the weight of the load can quickly be read on the display at any desired time during the operation of loading a vessel. Moreover, no inaccuracies arise due to wave action.
A drawback of these pressure sensor combinations is that the pressure-sensitive element may easily be damaged, especially during sailing. The pressure-sensitive element usually comprises a diaphragm which, in mounted condition, is located adjacent to the bottom face of the wall of the ship. Consequently, the pressure-sensitive element is particularly vulnerable and may for instance easily be damaged by objects and dirt floating in the ambient water. Preferably, the pressure sensor combination is placed in the bottom of the vessel, as a result of which this vulnerability increases much further. An inland ship, for instance, will often grind over the bottom of a river or canal, so that the pressure-sensitive element may be heavily damaged and consequently becomes entirely useless. A possible solution for preventing the pressure-sensitive element from being damaged could be found in placing the pressure-sensitive element by a certain depth within the outer surface of the ship surface, so that it can be damaged less easily. However, this has as a drawback that an air bubble of an unknown size may be located between the pressure-sensitive element and the outer surface of the ship surface. As a result, a lower water pressure will be measured by the pressure-sensitive element and an unknown difference in draft will be measured, corresponding to the unknown vertical height of the air column which is located under the pressure-sensitive element. If this vertical height of the air column is for instance 1 cm, a draft will be measured which is 1 cm less than the actual draft. This last has again as a result that a load weight is determined which is too low. Depending on the size of the vessel, this may result in an inaccuracy in the weight of the load in the order of magnitude of tons. This last is completely unacceptable.
The object of the invention is to overcome all above-mentioned drawbacks, and to this end, the invention is characterized in that the pressure sensor combination comprises a movable valve capable of at least partly releasing and closing a passage from the ambient water to the pressure-sensitive element. If necessary, the valve will close this passage so as to protect the pressure-sensitive element against damage from outside. In this connection, it is possible to place the pressure-sensitive element directly below the bottom face of the pressure sensor combination, so that the vertical height of the above-mentioned air column is bound to a well and acceptably defined maximum. As a result, the inaccuracy of the pressure sensor combination is also known. This involves the possibility of determining the above-mentioned draft with an inaccuracy which is for instance less than 3 mm.
In particular, the pressure sensor combination comprises a channel which originates adjacent to the pressure-sensitive element and ends in an opening of the pressure sensor combination to the ambient water, the valve being coupled to the rest of the pressure sensor combination for movement in the longitudinal direction of the channel through a limited path, and the valve in a first extreme position at least partly releasing the opening and in a second extreme position at least partly closing the opening. In this second extreme position, the pressure-sensitive element cannot be damaged from outside. In accordance with a preferred embodiment, the valve at least partly releases the opening when no external forces are being applied to the valve. Hence, if there is no a danger that the pressure-sensitive element can be damaged, this passage is released. Only when dirt, an object or the bottom of an ambient water approaches the pressure sensor combination and contacts the valve, will the valve thereby be brought into its second extreme position and accordingly protect the pressure-sensitive element. Preferably, the valve will at least partly release the opening under the influence of gravity, when no external forces are being applied to the valve. This is important in particular when the pressure sensor combination is mounted in the bottom of a vessel. However, it is also possible to use for instance a spring for releasing the opening at least partly when no external forces are being applied to the valve. This last will commonly be used when the pressure sensor combination is mounted in a side wall of the vessel.
In accordance with another aspect of the invention, when the pressure sensor combination is mounted in the wall of the vessel, a part of the valve is located outside the wall of the vessel in the ambient water when it is in the first extreme position and inside the wall of the vessel when it is in the second extreme position. Hence, when the wall of the vessel chafes along an object or the bottom, this part of the valve will be pushed toward the second extreme position and accordingly protect the pressure-sensitive element. In accordance with an advantageous embodiment of the invention, the channel at least comprises a first and a second channel portion, adjoining each other, the first channel portion being located adjacent to the opening, the second channel portion being located between the first channel portion and the pressure-sensitive element, the valve at least comprising a first and a second valve part, adjoining each other, the second valve part being at least partly located within the second channel portion, the first valve part having a largest diameter which is greater than a smallest diameter of the second channel portion and smaller than the diameter of the opening, the first valve part in the first extreme position being at least partly located outside the first channel portion and in the second extreme position being located inside the first channel portion and closes this passage accordingly. Preferably, the pressure sensor combination comprises a bottom face wherein the above-mentioned opening is located, the second valve part having a convex outer surface, an edge of which, in the first position, is precisely within the bottom face. According to this construction, the valve will not start vibrating during sailing and ensure a proper streamlining of the wall of the vessel. Moreover, the valve will react very adequately to an object, river bottom or dirt which threatens to damage the pressure-sensitive element.
In accordance with a highly economically favorable embodiment of the invention, the channel comprises a third channel portion, located between the pressure-sensitive element and the second channel portion, and the valve comprises a third valve part at least partly located inside the third channel portion, adjoining the second valve part and having a largest diameter greater than the smallest diameter of the second channel portion. Accordingly, the valve is connected to the rest of the pressure sensor combination so as to be movable in a very simple manner. Preferably, the first channel portion and the first valve part taper off, at least partly, in the direction from the opening to the pressure-sensitive element. This ensures a proper sealing in the second extreme position.
In accordance with another aspect of the invention, the pressure sensor combination comprises a valve housing on which the valve is movably mounted, the second channel portion being located inside the valve housing. Preferably, the first and third channels are at least partly located inside the valve housing. Usually, the pressure sensor combination comprises a sensor housing wherein the pressure-sensitive element is contained, the pressure-sensitive element of the sensor housing in mounted condition being located adjacent to a side of the valve housing facing away from the outer side. This has as an effect that mounting and dismounting is easy. Moreover, the sensor housing can easily be changed without removal of the valve. This also provides the possibility of using an at least practically unmodified, known sensor housing to which a valve housing with a valve are added. Preferably, the pressure sensor combination comprises a basic housing suitable for being mounted in an opening of the wall of a vessel, the valve housing in mounted condition being located inside the basic housing and the sensor housing in mounted condition being at least partly located inside the basic housing. To render mounting particularly easy, the valve housing, sensor housing and basic housing are cylindrical. In this connection, it is advantageous if the cylinder outer surface of the valve housing and at least a part of the sensor housing are provided with a thread and the cylinder inner surface of the basic housing is at least partly provided with a thread permitting the valve housing and the sensor housing to be screwed into the basic housing.
In accordance with a highly advanced embodiment of the invention, the pressure sensor combination comprises control means for operably bringing the valve from the first to the second extreme position and vice versa. In this manner, the valve can for instance be brought into its second extreme position from the pilot house when it is known that the danger of damage to the pressure-sensitive element is substantial. This can be realized in a very simple manner by providing the valve with a permanent magnetic material and bringing it from the first to the second extreme position and vice versa by means of a controllable, reversible magnetic field.
The invention will be further explained with reference to the accompanying drawings, in which:

Fig. 1 shows a pressure sensor combination according to the invention in dismounted condition;
Fig. 2 shows a pressure sensor combination according to the invention in mounted condition;
Fig. 3 is a top plan view of a valve of Figs 1 and 2;
Fig. 4 shows a valve housing with valve of Figs 1 and 2 in a second extreme position.

In Figs 1, 2, 3 and 4, corresponding parts have been provided with the same reference numerals. In these figures, reference numeral 1 designates a ship wall wherein, in Fig. 1, a pressure sensor combination 2 is mounted. Usuallly, the ship wall is the flat, practically horizontal bottom of the vessel, but it may also be a side wall of the ship. However, in Figs 1 and 2 the pressure sensor combination is placed in a horizontal bottom 1 of a vessel. The pressure sensor combination comprises a valve housing 4 accommodating a valve 6 which, in this case, is movable up and down through a limited path. Further, the pressure sensor combination comprises a sensor housing 8, accommodating, at the bottom end thereof, a water pressure-sensitive element 10. In this case, the water pressure-sensitive element 10 comprises a diaphragm. However, it is also possible to use other known pressure readers. A water pressure measured by the pressure-sensitive element is converted into a signal which represents this pressure on line 12. Further, the pressure sensor combination comprises a basic housing 14 mounted in an opening 16 of the ship wall 1. For this purpose, the basic housing is connected to the ship wall 1 by a weld 18 on the inside 20 of the vessel. The outside of the vessel, i.e. the ambient water, is designated by reference numeral 22.
The pressure-sensitive element 10 is in communication with the ambient water via a passage 24, to be further described hereinafter, which ends in an opening 26 in the bottom face 28 of the pressure sensor combination 2. For this purpose, the pressure sensor combination comprises the passage 24, composed of a first channel portion 30 partly tapering off in the direction from the opening 26 to the pressure-sensitive element 10. Adjacent to the opening 26 and as far as the opening, however, the first channel portion 30 has a constant diameter through a path here designated by reference numeral 32. A second channel portion 34 is located between the first channel portion and the pressure-sensitive element 10. The second channel portion 34 has a constant diameter and directly adjoins the first channel portion 30. Finally, the pressure sensor combination comprises a third channel portion 36, adjoining the pressure-sensitive element 10 on the one hand and the second channel portion 34 on the other. Preferably, the pressure-sensitive element is slightly recessed in the sensor housing as indicated by reference numeral 38. This involves that the side wall of the first channel portion 30 is formed by a portion of the basic housing 14 and a portion of the valve housing 4. The side wall of the second channel portion 34 is formed by the valve housing. The side wall of the third channel portion 36 is formed by a portion of the valve housing 4 and a portion of the sensor housing 8.
The valve 6 is composed of a first valve part 40 which tapers off in the direction from the opening 26 to the pressure-sensitive element 10 and has a convex surface 42. A second valve part 44 directly adjoins the first valve part 40 and has a constant diameter. Finally, the valve 6 comprises a third valve part 46 which directly adjoins the second valve part 44 and tapers off in the direction from the pressure-sensitive element 10 to the opening 26. The third valve part 46 further comprises at least one valve channel 47 as shown in Fig. 3 in a view according to the arrow p of Fig. 2. The depth a in radial direction of the valve channel 47 is constructed so as extend at least beyond the side wall 49 of the second channel portion 34, so that in a first extreme position an open communication 51 is present between the third and the second channel portion. The largest diameter d3 of the third valve part 46 is greater than the smallest diameter D2 of the second channel portion 34, which, in this case, is constant. Consequently, when the pressure sensor combination is disposed in a horizontal bottom 1, the valve 6 cannot fall from the valve housing 4. The largest diameter d1 of the first valve part 40 is also greater than the smallest diameter D2 of the second channel portion 34. As a result, the path of travel of the valve is also limited in the direction from the opening 26 to the pressure-sensitive element 10. Hence, the first and second valve parts 40, 46 function as members cooperating with the valve housing 4, which determine the first and second extreme positions. In addition, the first valve part 40, in cooperation with the valve housing 4, functions as a shut-off member when the valve 6 is in the second extreme position. Preferably, the largest diameter dl of the first valve part is smaller than the diameter D1 of the opening 26. The largest diameter of the third valve part 46 is also smaller than the smallest diameter D3 of a third channel portion 36 located in the valve housing. Likewise, it applies that the largest diameter d2 of the second valve part 44 is smaller than the smallest diameter D2 of the second channel portion 34.
This has as a result that the valve 6 can move in vertical direction through a limited path. The length H2 of the second channel portion 34 is smaller than the length h2 of the second valve part 44 in the longitudinal direction of the second channel portion 34. In a first extreme position, as is shown in Figs 1 and 2, the passage 24 is not closed off. However, when the wall of the ship, and in particular the surface 42 of the valve 6 contacts an object, this object will move the valve 6 in the direction of the pressure-sensitive element and in a second extreme position, shown in Fig. 4, close the passage 24. As a result, the pressure-sensitive element is well-protected against damage. Also in the case where the bottom of the vessel grinds over the ground, the valve 6 will be moved toward the second extreme position through the contact with the bottom.
Preferably, when the valve 6 is in its first extreme position, the edge 48 of the first valve part 40 is precisely within the opening 26, i.e. precisely below the bottom face 26. This prevents the valve from fluttering and vibrating, possibly, during sailing, due to the flow of the ambient water. When in its second extreme position, the valve 6 is preferably entirely within the basic housing (see Fig. 4), so that it cannot be damaged when the ship wall 1 for instance grinds over the bottom of a river.
Due to gravity, the valve 6 will move toward its first extreme position when no external forces are being applied to the valve 6. The pressure sensor combination may moreover be provided with a spring 50, causing the valve 6 to move toward its first extreme position when no external forces are being applied to the valve 6. This allows the pressure sensor combination also to be used successfully in a practically vertical wall of a vessel.
Preferably, valve housing 4, valve 6, sensor housing 8 and basic housing 14 are rotational-symmetric round an axis through arrow p. The outside of the valve housing 4 and the sensor housing are provided with thread 52. Likewise, the inside of the basic housing 14 is provided with thread 54 which is complementary to the thread 52. Hence, the valve housing can be screwed into the basic housing 14 from the inside of a vessel. Subsequently, the sensor housing can be screwed into the basic housing onto the valve housing 4. However, it is also possible to integrate sensor housing, valve housing and/or basic housing into a non-separable unit.
Finally, it is observed that it is possible to construct the valve 6 of a permanent magnetic material and to construct the sensor housing and the valve housing of a material which is difficult to magnetize. By means of a coil 56, a magnetic field can be generated which selectively moves the valve 6 toward a first or second extreme position, depending on the direction of the magnetic field.

Claims

A pressure sensor combination suitable for being mounted in the outer wall of a vessel permitting a water pressure-sensitive element of the pressure sensor combination to be in contact with the ambient water, characterized in that the pressure sensor combination comprises a movable valve capable of at least partly releasing and closing a passage from the ambient water to the pressure-sensitive element.
A pressure sensor combination according to claim 1, characterized in that the pressure sensor combination comprises a channel originating adjacent to the pressure-sensitive element and ending in an opening of the pressure sensor combination to the ambient water, the valve being coupled to the rest of the pressure sensor combination for movement in the longitudinal direction of the channel through a limited path, and the valve in a first extreme position at least partly releasing the opening and in a second extreme position at least partly closing the opening.
A pressure sensor combination according to claim 2, characterized in that the valve at least partly releases the opening when no external forces are being applied to the valve.
A pressure sensor combination according to claim 3, characterized in that under the influence of gravity, the valve at least partly releases the opening when no external forces are being applied to the valve.
A pressure sensor combination according to any one of claims 2-4, characterized in that when the pressure sensor combination is mounted in the wall of the vessel, a part of the valve is located outside the wall of the vessel in the ambient water when it is in the first extreme position and inside the wall of the vessel when it is in the second extreme position.
A pressure sensor combination according to any one of claims 2-5, characterized in that the pressure sensor combination comprises a bottom face provided with said opening and whose outer side, in mounted condition, is located in the ambient water, a part of the valve in a first extreme position being located outside said bottom face in the ambient water and the valve in a second extreme position not being located ouside said bottom face at all.
A pressure sensor combination according to claim 6, characterized in that in mounted condition the outer surface of the vessel and the bottom face of the pressure sensor combination lie in one plane.
A pressure sensor combination according to any one of claims 5-7, characerized in that the channel at least comprises a first and a second channel portion, adjoining each other, the first channel portion being located adjacent to the opening, the second channel portion being located between the first channel portion and the pressure-sensitive element, the valve at least comprising a first and a second valve part, adjoining each other, the second valve part being at least partly located within the second channel portion, the first valve part having a largest diameter which is greater than a smallest diameter of the second channel portion and smaller than the diameter of the opening, the first valve part in the first extreme position being at least partly located outside the first channel portion and in the second extreme position being located inside the first channel portion and thereby closing said passage.
A pressure sensor combination according to claim 8, characterized in that the second valve part has a convex outer surface, an edge of which, in the first extreme position, is precisely within the bottom face.
A pressure sensor combination according to claim 8 or 9, characterized in that the channel comprises a third channel portion, located between the pressure-sensitive element and the second channel portion, and the valve comprises a third valve part at least partly located inside the third channel portion, adjoining the second valve part and having a largest diameter greater than the smallest diameter of the second channel portion.
A pressure sensor combination according to any one of claims 8-10, characterized in that the first channel portion and the first valve part taper off, at least partly, in the direction from the opening to the pressure-sensitive element.
A pressure sensor combination according to any one of claims 8-11, characterized in that the third channel portion and the third valve part taper off, at least partly, in the direction from the pressure-sensitive element to the opening.
A pressure sensor combination according to any one of claims 8-12, characterized in that the pressure sensor combination comprises a valve housing on which the valve is movably mounted, the second channel portion being located inside the valve housing.
A pressure sensor combination according to any one of claims 8-12 and 13, characterized in that the first and third channels are at least partly located inside the valve housing.
A pressure sensor combination according to claim 13 or 14, characterized in that the pressure sensor combination comprises a sensor housing wherein the pressure-sensitive element is located, the pressure-sensitive element of the sensor housing in mounted condition being located adjacent to a side of the valve housing facing away from the outer side.
A pressure sensor combination according to claim 15, characterized in that the pressure sensor combination comprises a basic housing suitable for being mounted in an opening of the wall of a vessel, the valve housing in mounted condition being located inside the basic housing and the sensor housing in mounted condition being at least partly located inside the basic housing.
A pressure sensor combination according to claim 16, characterized in that the valve housing, sensor housing and basic housing are cylindrical.
A pressure sensor combination according to claim 17, characterized in that the cylinder outer surface of the valve housing and at least a part of the sensor housing are provided with a thread and the cylinder inner surface of the basis housing is at least partly provided with a thread permitting the valve housing and the sensor housing to be screwed into the basic housing.
A pressure sensor combination according to any one of claims 10-18, characterized in that the third valve part comprises at least one valve channel which is part of said passage when the valve is in its first extreme position.
A pressure sensor combination according to any one of the preceding claims, characterized in that the pressure sensor combination comprises control means for operably bringing the valve from the first to the second extreme position and vice versa.
A valve housing with a valve according to any one of claims 13-20.
A sensor housing according to any one of claims 15-20.
A basic housing according to any one of claims 16-20.