Claims:
I claim
1. A bilge pump for a boat and driven by wave movements, comprising:
2. A bilge pump according to claim 1, wherein said second one-way valve means is associated with said pump piston.
3. A bilge pump according to claim 2, wherein said pump piston includes a sleeve slidably disposed within said bore, said piston rod having its lower end passing freely through said sleeve so as to provide a substantial clearance therebetween, and said second one-way valve means including a valve member disposed on the lower end of said piston rod and positioned for engagement in a sealing manner with the lower end of said sleeve when the piston rod is drawn upwards for causing the sleeve to operate as a piston and move upwardly for discharging the water above the piston through the outlet, said piston rod further having means provided thereon spaced upwardly from said valve member and disposed for engagement with the upper end of the sleeve when the piston rod is moved downwardly, said last-mentioned means engaging the sleeve after the piston rod has moved downwardly a distance sufficient to move the valve member away from the sleeve so as to permit flow of water therethrough, whereby continued downward movement of the pump rod causes said means to engage the sleeve so as to move same downwardly.
4. A bilge pump according to claim 1, wherein a third one-way valve means is situated adjacent the inlet to the pump means for preventing backflow of water from the bore into the hose means.
5. A bilge pump according to claim 1, wherein said float means comprises a slab of plastic foam material.
6. A bilge pump according to claim 1, wherein said other end of said hose means is provided with filter means on the upstream side of said first one-way valve means.
7. A bilge pump according to claim 1, wherein said elongated flexible cablelike element for connecting the pump housing to the boat permits the pump means and the float means associated therewith to freely respond to and follow the water movements independently of the pitching or rolling movements of the boat.
Description:
The present invention relates to a bilge pump for boats arranged to automatically keep a moored boat pumped out and free from bilge water, the requisite energy for pumping being obtained from the movement of waves in the surrounding water and from the rolling and pitching movements characteristic of boats.
Automatic bilge pumps of the dynamic or static type are previously known. In general, the dynamic-type bilge pumps consist of a constricted tube fitted into the hull of boats, the venturi action of the tube during the travel of a boat through the water creating an under pressure which evacuates the bilge water lying inside the boat hole. However, a certain amount of risk is connected with this type of pump because it is dependent on a nonreturn valve which functions perfectly in order that the water shall not flow back and leak out into the boat when it is moored. Static pumps which are driven by the wave movements of the surrounding water generally consist of some form of membrane-pump actuated by a lever with a float fixed to one end. This type of pump is operated in such a manner that when the boat has been moored, the lever and float are put over the side, the constant motion of waves and rolling creating a pumping action. However, this type of pump is complicated and inconvenient in use and has never been generally used, despite the obvious need of a special pump device with which it is possible to keep a sail or motorboat hull dry and free from water inboard.
Thus the object of the present invention is to devise an automatic bilge pump driven by the movement of waves or pitching and rolling characteristic of small boats, a pump which is also simple and easy to use and which comprises a separate, robust unit, that at need can simply be suspended over the gunwale of a boat and be allowed to operate during the hours of darkness etc. The object of the present invention is achieved and the aforementioned disadvantages connected with previously known pumps of a similar type are removed by the characterizing features of the bilge pump according to the present invention.
The invention will be more closely described for the purpose of exemplification while referring to the appended drawing, in which:
FIG. 1 is a view drawn partially in section and partially as a perspective of the bilge pump according to the present invention in the operating position with a hose connection running inboard through which the bilge water is evacuated;
FIG. 2 is a longitudinal section through the pump cylinder or tube; and
FIG. 3 is a longitudinal section through a single-way induction valve (nonreturn valve) which can be used at the inboard end of the exhaust hose .
As is made apparent by FIGS. 1 and 2, the bilge pump according to the invention comprises a fairly long pump cylinder in the form of a tube 4, which at its lower end is associated with a weight in the form of a solid cylindrical body 7. A nipple 11 has been arranged which is welded at the top and in the side of the cylindrical body, the nipple 11 communicating with the interior of the tube 4 as illustrated in FIG. 2. An exhaust hose 5 of suitable material, e.g., rubber or plastic, is connected to the nipple as shown. A metal wire eye 11a is brazed or welded between the nipple 11 and the weight 7, the weight and the pump tube 4 being suspended by this eye by means of a line 12 supported by the gunwale of a boat, which is shown schematically at 13. Hereby, the tube 4 is completely immersed in the water, the upper end of the tube being a short distance under the surface of the water.
A piston 3 which is displaceable by means of a rod 2 is provided in the pump tube 4. At its upper end the rod 2 is united with a float or buoyant body 1, which may simply be made of a cellular plastic member, and which floats on the surface of the water, the support line 12 passing through a hole 1a in the float. At this point in the description it is apparent that if the surface of the water moves in variance to the gunwale of the boat, either due to the formation of waves or due to the rolling of the boat, the float 1 will move and thereby cause the pump piston 3 to slideably move itself in relationship to the cylinder 4, solely on the condition that the body 7 has a weight proportional to the resistance set up by the movement of the piston in the cylinder, and that the line 12 is constantly kept taut.
In the embodiment illustrated, the piston is arranged to pump water from below its lower end to above its upper end. In order to fulfill this purpose the piston can for example consist of a sleeve 9 free to slide in the tube 4, through which the pump rod 2 passes freely with a large amount of clearance. The rod is provided at its lower end with a valve cone 14 which engages in a sealing manner at the bottom of the sleeve, the sleeve forming a valve seat surrounding the opening therein when the rod is drawn upwards. When the rod 2 is propelled downwards, the cone valve 14 leaves its seat and instead the sleeve is engaged at its upper end by a transverse pin 15 arranged on the rod 2, which draws the pump sleeve 9 downwards, the water then being able to flow freely through the piston. By this simple method a single-direction pump action can be effected, on the condition of course that the water induced into the tube 4 is prevented from flowing back into the hose 5 when the piston moves downwards.
For this purpose, a second valve is provided, and in the illustrated embodiment such a valve 6 is fitted into the inboard end of the hose 5, as shown in FIG. 3, but it is even possible to provide the piston with a nonreturn valve which takes the form of a ball, which seals against a seat arranged in the piston. In order to increase the pump effect and ensure that the pump operates efficiently even when piston movements are very limited, an extra nonreturn valve can be arranged at the inlet of the cylinder, as illustrated by the dotted line at 8a in FIG. 2.
Therefore, if the bilge pump according to the invention is suspended over the gunwale of the boat, and its suction hose is lead inboard and the end 16 having the nonreturn valve 6 thereon is situated in the bilge water of the boat, the equipment being arranged approximately as shown in FIG. 1, the buoyant member 1 will follow the movement of the waves and via the rod 2 move the piston 3 up and down in the tube 4. When the piston is drawn upwards, its through-flow is cut off by the valve cone 14, and water is sucked into the tube 4 through the hose 5 and the nonreturn valve 6, which opens the tube 5 having a filter 19 on the end thereof. Subsequently, when the piston 3 moves downwards, the valve 6 closes due to ball valve 8 contacting valve seat 17 and the water flows up through the piston, the passage through the piston sleeve 9 being now open. During the following upward pump stroke, the water existing above the piston is expelled into the surrounding water through the holes 10 in the upper end of the tube 4 (or the hole in the plug 4a sealing the tube and acting as a guide for the pump rod 2). With this arrangement, even if the motion of waves is only moderate, an average sized sailboat will be pumped dry in a very short time.
The tube 4 is fairly long in comparison to the length of the pump stroke, this signifies that the height of the pump in the water need never be adjusted with any special accuracy, the pump piston being able to execute any length of stroke anywhere along the length of the pump cylinder or the pump tube. If the water should be shallow, the pump need not be supported by the boat but can be driven by its point into the sea bottom. To allow this the lower end of the weight 7 has been designed as a point 7a.
In the embodiment of the valve system illustrated it is to be observed that the arrangement itself is of no special importance and other embodiments may be employed. The pump piston 3 can be provided with a one-way ball valve similar to that of the hose valve 6. Furthermore, the valve of the piston need not be positioned solely in the piston, it may be replaced by a fixed return valve arranged for example in the upper portion of the weight 7 or in the nipple 11. In this embodiment the piston 3 is then entirely enclosed, and during its upwards movement induces water into the cylinder, which during the downwards stroke of the piston is driven out into the surrounding water by the alternative, fixed nonreturn valve. Concerning the integral valve elements used, it is possible, in addition to the ball valves, to use many other elements known per se, e.g., flaps, tongues, membranes and the like.
It is also possible to employ many other embodiments during the practical construction of the automatic bilge pump according to the invention. The core of the inventive idea is to be found in the novel, simple method of effecting pumping movements by means of a buoyant member following the movements of waves, the buoyant member directly activating a pump piston in the cylinder, which is fixed in relation to the boat or lake or sea bottom. Within the basic framework of this invention it will be possible for those skilled in the art to effect many different embodiments suitable for and fitting different conditions.