ARRANGEMENT FOR WATER-COOLED MARINE ENGINES

Abstract: Arrangement for water-cooled marine engines which exhibit at least one suction opening (7) and at least one discharge opening (8) for cooling water. The openings are intended to be situated beneath the surface of the water surrounding the vessel in which the engine is installed. Between the openings and the engine run a first and a second line (1, 2) for the transport of the cooling water which is to be carried to and from the engine. A changeover arrangement is able to switch the connection between the openings (7, 8) and the lines (1, 2) in such a way that for a given period the first opening is connected to the first line and the second opening is connected to the second line, whilst during an immediately following period the first opening is connected to the second line and the second opening is connected to the first line, and so on. Any impurities which may have become trapped in the first opening by suction when this was being used as a suction opening will thus be washed away when it is used as a discharge opening during the following period.

Description: Title of the invention: Arrangement for water—cooled marine engines Technical Field: The present invention relates to an arrangement for water—cooled marine engines which exhibit at least one suction opening and at Least one discharge opening for cooling water, said openings being intended to be situated beneath the surface of the water surrounding the vessel in which the engine is installed, in which case there run between the openings and the engine a first and a second line for the transport of the cooling water which is to be carried to and from the engine. Description of the prior art In the case of engines which are mounted in vessels and whiGh are water—cooled, the medium utilized for cooling the engine is the surrounding water, which is sucked in and pumped round inside the engine or a heat exchanger in order to provide indirect cooling, whereupon it is once more discharged. At the inlet point for the water is arranged a filter or a sieve so as to ensure that the channels in the engine or the heat exchanger and any pumps do not become choked with any impurities which may be present in the surrounding water. Technical problem: In the case of watercourses which contain impurities there is a risk that the inlet point for the cooling water will become choked, with the result that the engine will receive insufficient cooling water and may overheat. Solution: In order to eliminate the aforementioned risk of choking the arrangement in accordance with the invention is provided with an arrangement for changing over the connection between the openings and the lines in such a way that for a given period the first opening is connected to the first line and the second opening is connected to the second line,, whilst during an immediately following period the first opening is connected to the second line and the second opening is connected to the first line, and so on. In this way any impurities which may have become trapped in the first opening by suction when this was being used as a suction opening will be washed away when it is used as a discharge opening during the following period. Advantages: By means of the invention there is achieved a simple and reliable arrangement which eliminates the risk of the inlet point for the cooling water becoming choked. Description of the drawings: Two embodiments of the invention are illustrated in the Figures in the accompanying drawings. Fig. 1 is a schematic representation of a first embodiment, and Figs. 2 and 3 show the second embodiment, with Fig. 2 being more detailed and consisting of a cross—section, whilst Fig. 3 is more schematic and shows a partly sectioned view. Description of the preferred embodiments: The basic concept of the invention is that both the inlet and the outlet for the cooling water are fitted with filters or sieves, in conjunction with which an arrangement is provided for switching over the flows in such a way that one of the sieves, after having served as an inlet sieve for a s certain period, will serve as a discharge sieve for a following period, and vice versa. in this way any impurities which may have collected on the sieve during the inlet period will be washed away during the discharge period. The arrangement illustrated in Fig. 1 exhibits a first line 1 , which is connected to the inlet side for the cooling water on the engine or the aforementioned heat exchanger, and a second line 2 , which is connected to the outlet point on the OMPI WiPO engine or the heat exchanger. These lines are connected to a change—over valve 3 with an operating shaft 4 . Two lines 5 and 6 run from the change—over valve. The valve -3 is in this case so arranged that when it is in one operating position it will maintain the line 1 connected to the line 6 and the line 2 to the line 5 , whereas when it is in its other operating position it will maintain the line 1 connected to the line 5 and the line 2 to the line 6 . Change—over valves of this kind are previously disclosed and do not require to be described in any greater detail here. The two lines 5 and 6 terminate outside the planking of the vessel and beneath the surface of the water, and each is fitted with its own sieve 7 and 8 . The operating shaft 4 exhibits a lever arm 10 , to the outer end of which is connected a so—called ovei—centre spring 11 and a second spring 12 referred to in the following as the driving spring. The driving spring 12 is connected by its other end to the free end of a second lever arm 13 , referred to below as the driving arm, which is supported on a shaft 14 and is acted upon by a crank pin 15 which is driven round by a slowly— otating motor 16 . In the embodiment in accordance with Figs. 2 and 3 a valve arrangement 20 is formed from a housing 21 with a seat 22 and a guide 23 . Inside the frame run three channels, these being a discharge channel 24 , an inlet channel 25 and an operating channel 26 . The channels 24 and 25 are each situated in its own half of the guide, whilst the channel 26 extends along the centre of the guide. The channel 24 is connected to the outlet point for the cooling water on the engine which is to be served by the sieve arrangement 20 , and the channel 25 extends to the inlet point for the cooling water. The channel 26 is so arranged as to be connected alternately to the discharge point and the inlet point, as will be described in detail below. On the guide 23 is arranged a tubular slide 27 with a shell 28 and a base 29 . From the channel 24 there extend outwards as far as the outside of the guide 23 a first opening 30 and a second opening 31 . In the same way there extend inwards as far as the channel 25 from the outside of the guide two openings 32 and 33 . The aforementioned openings are matched by four openings in the slide 27 , which is so arranged as to interact with the aforementioned openings, so that a first opening 34 in the slide 27 will interact with the opening 30 , an opening 35 in the slide will interact with the opening 31 , an opening 36 in the slide will interact with the opening 32 and an opening 37 in the slide will interact with the opening 33 . The slide 27 is provided with rotational stops so that the openings in the slide cannot be rotated out of line with corresponding openings in the guide 23 , and with axial stops so that the slide can adopt not only the inner position illustrated in Fig. 2, but also an outer position. Axial displacement of the slide produces two areas of movement, these being an inner area within which the openings 34 and " 36 are able to move and an outer area within which the openings 35 and 37 are able to move. Both these areas are served by a single sieve 38 , although this sieve exhibits a separating wall 39 which forms two individual chambers 41 and 42 in it and within which the two areas of movement are sit ' uatedr The sieve is attached to the frame 21 by means of an end ring 40 which engages with the seat 22 . The openings in the guide 23 and the slide 27 are matched one to the other in such a way with regard to their axial positions that, with the slide in its inner position as shown in Fig. 2, the openings 31 and 35 will be directly in line with each other and the openings 32 and 36 will also be directly in line with each other. The other openings will, on the other hand, be displaced in relation to each other. In this way the channel 24 will be connected with the outer chamber 42 of the sieve 38 , and the channel 25 will be connected with the inner chamber 41 of the sieve. When, on the other hand, the slide 27 adopts its outer position, the situation will be reversed. The channel 24 will then be connected via the openings 30 and 34 with the inner chamber 41 of the sieve, whereas the channel 25 will be connected via the openings 33 and 37 with the outer chamber 42 of the sieve. The previously open connections will thus be closed. In Fig. 3 are shown not only the outlet line 43 , but also the inlet line 44 to which the channels 24 and 25 are connected. The channel 26 is connected to a third line 45 , which can be connected by means of a valve 46 either to the outlet line 43 or to the inlet line 44 . This can be achieved in the manner shown by means of a movable valve body 47 , which is so arranged as to be activated by means of an operating device 48 . Movement of the valve body 47 between its two end positions (in the end position shown in Fig. 3, the channel 26 is connected via the line 45 to the inlet line 44 ) takes place at certain intervals, and the control device 48 may be a slowly rotating electric motor which is capable of causing the valve body 47 to move backwards and forwards. In the event of indifferent positions occurring in which the valve body 47 is situated between its two seats, this will not be of any major significance to its function provided that the channels are sufficiently narrow as not to permit any noticeable flow to take place between the lines 43 and 44 . In order entirely to exclude the possibility of any such flow, check valves may be arranged between the lines 43 and 44 and the valve arrangement 46 . In the embodiment illustrated in Fig. 1 the motor 16 imparts a slow rotation to the crank pin 15 . This will then cause the driving arm 13 to move from side to side. In the position shown in Fig. 1, the driving spring 12 will be further tensioned if it is assumed that the driving arm 13 is caused to rotate further about its shaft 14 in an anti—clockwise direction. Once a certain level of tension has been reached the force of the spring 11 will be overcome and the lever arm 10 will swing rapidly over to the second operating position in which the connection between the lines 1 and 2 on the one hand and 5 and 6 on the other hand is reversed. As the crank pin 15 continues to move, the driving spring 12 will gradually be tensioned in the other direction and a new shift will take place, although this time in the opposite direction, thereby causing the flow to be switched in the lines 5 and 6 . Thus, during every other period, the sieve 7 will act as a suction sieve and the sieve 8 will act as a discharge sieve, whereas during the.intervening periods the situation will be the opposite. In the event of one of the sieves having become choked during the period when it acts as a suction sieve, it will be washed clean during the period when it acts as a discharge sieve. If it is assumed that the valve 3 is situated relatively close to the motor and that the lines 5 and 6 are relatively long, the switching of the flow will cause a relatively large quantity of discharged, heated water from the engine or the heat exchanger to be sucked back into the system. This can lead to problems if the lines are long, especially if they are also of large bore and contain a considerable quantity of water. Accordingly, it would be desirable if the switching—over could take place as close as possible to the inlet and outlet sieves. It is, of course, possible to move the valve 3 to the inlet and outlet points on the actual planking of the vessel, although in this case the valve will be situated at a certain distance from the motor and it may be desirable for the mechanical equipment constituted by the valve switch—over arrangement to be positioned adjacent to the motor installation. In the embodiment illustrated in Figs. 2 and 3, this has been achieved by the remote control of the valve arrangement. Remote control takes place in such a way that water under alternating pressure from the line 43 and water from the suction line 44 is connected to the cavity 50 which is formed between the ends of the guide 23 and the base 29 of the slide 27 . When the water under pressure is introduced via the channel 26 the slide 27 will be forced outwards so that the aforementioned connections with the slide in its outer position " will be achieved. Washing will thus take place via the inner cavity 41 of the sieve, and suction will take place via the outer cavity 42 of the sieve. During those periods when the channel 26 is connected with the suction line 44 the surrounding water will instead force in the slide 27 to the inner position shown in Fig. 2. In this case -ξU tA U G:ΛPI _ switched connections in accordance with Fig. 2 will be obtained. In this way the inner part of the sieve at the cavity 41 will be washed clean after each suction period by the water being discharged, and the same will be true of the outer part of the 5 sieve. The charactersitic feature of the invention is thus that the flows of water to and from the cooling water inlet and outlet are reversed periodically. As has been shown, this can take place by means of a valve arrangement near the engine or a valve 10 arrangement at the inlet and outlet. Reversal can also be achieved by shifting the direction of operation of the pump required to provide the flow of cooling water. However, there is unlikely to be any benefit from reversing the flow of the water through the engine or through the heat exchanger, for which reason a reversible 5 pump must be installed in conjunction with check valves. These may be arranged in a previously disclosed fashion to provide a flow in only one direction in * a particular line irrespective of the operation of the pump; this should be compared with the control of the alternating flow in a piston pump. The direction of 0 operation of the pump may be reversed most easily in the case of — an electrically driven cooling water pump, whereas a pump driven directly from the engine is more difficult to switch over. It has been assumed in the above that the switching over of the flow to the inlet and the outlet takes place periodically. 5 It is also possible to cause this to occur in relation to the choking of the inlet, which may be measured as a drop in pressure, as a reduced flow or as an increase in the temperature of the flow of cooling water. The start—up of the change—over mechanism and the start—up of the electric motor 16 and the operating device 0 48 can be initiated in this case by means of a sensor organ. 5

Claims: Patent Claims 1. Arrangement for water—cooled marine engines which exhibit at least one suction opening 7; 36) and at least one discharge opening (8; 35) for cooling water, said openings being intended to be situated beneath the surface of the water surrounding the vessel in which the engine is installed, in which case there run between the openings and the engine a first and a second line (1, 2; 43, 44) for the transport of the cooling water which is to be carried to and from the engine, c h a r a c t e r i z e d by an arrangement for changing over the connection between the openings (7, 8; 35, 36) and the lines (1, 2; 43, 44) in such a way that for a given period the first opening is connected to the first line and the second opening is connected to the second line, whilst during an immediately following period the first opening is connected to the second line and the second opening is connected to the first line, and so on, whereby any impurities which may have . become trapped in the first opening by suction when this was being used as a suction opening will be washed away when it is used as a discharge opening during the following period. 2. Arrangement in accordance with Patent Claim 1, c h a ¬ a c t e r i z e d in that the change—over arrangement is so arranged as to operate periodically in a timed cycle. 3. Arrangement in accordance with Patent Claim 1, c h a r ¬ a c t e r i z e d in that the change—over arrangement is so arranged as to be activated by the indication of certain limit values relating to the cooling water, for example its pressure or temperature. 4. Arrangement in accordance with Patent Claims 2 or 3, c h a r a c t e r i z e d in that the change—over arrangement includes valve arrangements (4, 10; 28) so arranged as to switch the connection between the two openings (7, 8; 35, 36) and the two lines C1, 2; 43, 44). 5. Arrangement in accordance with Patent Claim 4, c h a r ¬ a c t e r i z e d in that for the purpose of operating the valve arrangement ( 28) there is provided a hydraulic cylinder (50) in which the cooling water is utilized as the pressure medium, in which case an auxiliary valve arrangement (46, 47) is provided for the purpose of controlling the flow of the cooling water to and from the hydraulic cylinder.

Inventors: BERGDAHL KNUT, BERGDAHL, KNUT
Applicants: NP NEW PROD NORDINVENT INVEST, N.P. - NEW PRODUCTS NORDINVENT INVESTMENT AB
Application year: 1983
Main classification: B63H21
IPC codes: F01P11