The present invention relates to exhaust valves comprising a valve housing, a valve seat formed therein and a valve element supported by movable supporting means for moving the valve element into and out of sealing contact with the valve seat. The invention particularly relates to exhaust valves of this kind for use in the exhaust duct from the en- gine of a submarine.

One problem inherent in exhaust valves is that due to the flow of usually hot exhaust gases through the valve, dust particles and impurities tend to de¬ posit on the sealing surfaces of the valve element and the valve seat, and this gradially reduces the sealing effect of the valve. In order to reduce the amount of remaining deposits on the sealing surfaces of the valve element and on the valve seat, it is previously known in exhaust valves used in internal combustion engines to impart to the valve element a certain small rotary motion in connection with open¬ ing and closing of the valve, so that each time the valve element moves into contact with the seat it has been rotated a small angle in relation to the valve seat. Even if this to a certain extent may have a cleaning effect it does not provide such grinding effect as obtained by relative movement be¬ tween the sealing surfaces, and as required in order to effciently remove impurities which have adhered to said sealing surfaces. This may be one of the reasons why the method mentioned above has not been practised in exhaust valves of the kind used in the exhaust ducts of engines of submarines. When using exhaust valves of this kind it has proved necessary to dismount the valve regularly at relatively short

intervals and to carry out grinding of the sealing surfaces between the valve element and the valve seat by means of special grinding tools.

One object of the present invention is to pro- vide an exhaust valve of the kind mentioned initial¬ ly, in which an efficient gringing action on the sealing surfaces between valve element and valve seat is obtained each time the valve is opened and closed, said grinding action being obtained by re- lative movement between the sealing surfaces, said surfaces simultaneously being urged towards each other by a predetermined pressure force. Another object of the invention is to provide an exhaust valve including means which automatically provides said grinding action and which is simple with re¬ spect to its design and which without difficulty may be included into the supporting device used for mov¬ ing the valve element into and out of engagement with the valve seat. The objects mentioned above are obtained by means of a design in accordance with the appended claims.

The invention will be described below with re¬ ference to an embodiment of an exhaust valve of the kind used in the exhaust duct from the engine of a submarine and which is illustrated on the appended drawing, on which

- fig 1 is a longitudinal section through an ex¬ haust valve in accordance with the invention, and - fig 2 is a section taken as indicated by I - I in fig 1.

The exhaust valve illustrated in the figures include a substantially spherical valve housing 1 provided with two pipe sockets 2 and 3 respectively connected with the valve housing and extending co-

axially with respect to each other. The pipe socket 2 extends a certain distance into the valve housing and terminates into a circular valve seat 4 co¬ operating with a valve disk 5 which may be brought into engagement with the valve seat. By means of a supporting device 6 which is swingably mounted in the valve housing 1, the valve disk 5 may be swung between closed position as indicated by unbroken lines in fig 1 and open position as indicated by dash~and-dot lines in fig 1. This supporting device 6 includes a shaft 7 rotatably supported in the valve housing 1, said shaft extending within the valve housing 1, through the walls thereof and ter¬ minates outside the valve housing. At least one end of said shaft 7 is connected to hydraulic, pneu¬ matic, electrical or other power means, by means of which shaft 7 may be rotated between two angular positions. Shaft 7 is disposed sideways and above the valve seat 4 and extends in parallel with a plane through the upper edge of the valve seat 4. Inside the valve housing 1 the shaft 7 is rigidly connected with a hub 8 from which an arm 9 extends in the direction towards the valve seat. Supported at the free end of arm 9 is a preferably cylindrical sleeve 10 of annular cross section, said sleeve ex¬ tending coaxially with the pipe socket 2. A rod 11 of circular cross section is axially displacable in said sleeve 10 and extends through end walls 12, 13 of said sleeve. At the end portion of rod 11 extend¬ ing towards the valve disk 5, rod 11 is connected to the valve disk 5 so that a rotational movement of rod 11 about its own axis is transmitted to the valve disk 5, thus imparting to the valve disk a corresponding rotational movement. As shown in fig 1 the connection between rod 11 and valve disk 5 is

obtained by means of a spherical, ball-like member

14 formed at the end of rod 11, said spherical member being provided with two pins 15 extending from the spherical member 14 in opposite directions. The spherical member or ball 14 including the pins

15 is jounaled in the hub 5A of the valve disk 5 so that valve disk 5 will have a certain freedom of movement with respect to the rod 11, but so that when rod 11 is being rotated about its own axis, a corresponding rotational movement is imparted to the valve disk. Inside sleeve 10 the rod 11 is provided with a washer 16, rigidly connected to the rod. Dis¬ posed between the washer 16 and the upper end wall 13 of sleeve 10 is a compression spring 17 which continuously exerts a pressure force on the washer and thus on rod 11 in the direction towards the valve seat. The sleeve 10 is provided with stops 18 disposed on the inner surface of the sleeve above the washer 16, said stops limiting the movement of washer 16 in the sleeve 10 between the bottom 12 thereof and said stop 18. Washer 16 is further pro¬ vided with grooves, which cooperate with a cor¬ responding number of rims 19 which are rigidly con¬ nected with sleeve 10 on the inside thereof between the bottom 12 of the sleeve and said stops 18. The rims 19 extend under a certain inclination with re¬ spect to the direction of the central axis of rod 11 and sleeve 10 respectively, so that when rod 11 is being displaced in the axial direction of the sleeve 10, a rotational movement about its own axis is im¬ parted to rod 11 by means of washer 16. As mentioned previsously the rotational movement is transmitted to the valve disk 4. Axial displacement of rod 11 thus imparts a rotational movement to the valve disk corresponding to the rotational movement of rod 11.

When opening the valve, which is shown in its closed position in fig 1, the arm 9 is made to swing counter-clockwise by rotating shaft 7 counter clock¬ wise. During the first sequence of said swinging movement the valve disk 5 will remain in contact with the seat 4 under the influence of the force of the conpression spring 17, due to the fact that spring 17 expands. Due to this rod 11 is displaced axially with respect to the sleeve, a rotational movement at the same time being imparted to rod 11 via rims 19 and washer 16. This rotational movement is transmitted to the valve disk which thus is caus¬ ed to carry out a corresponding rotational movement. During this rotational movement the valve disk is still urged by pressure force towards the valve seat under the influence of the force exerted by the spring. Due to this rotational movement, the valve disk performs a periferal sliding movement along the valve seat, thus exerting a grinding action on the valve seat, and due to this the valve seat is kept free from impurities. The swinging movement of arm 9 is continued until the fully open position of the valve has been reached, as indicated by dash-and-dot lines in fig 1.

When closing the valve arm 9 is made to swing in the opposite direction, i e clockwise. Under the influence of the force from spring 17 the washer 16 in the sleeve 10 is kept in abutment against the bottom wall 12 of the sleeve 10. When the valve disk 5 during continued swinging movement has ben swung into engagement with valve seat 4, continued swing¬ ing movement of arm 9 results in that rod 11 is dis¬ placed with respect to the sleeve 10, at the same time compressing spring 17. Via rims 19 and washer 16 a rotational movement is imparted to the rod 11

and thus also to the valve disk 5. During this rota¬ tional movement the valve disk 5 is in engagement with the valve seat 4, thus exerting a grinding ac¬ tion on the seat.

The invention is not limited to the embodiment described above with reference to the figures, but may be subject to modifications within the scope of the appended claims.