SEALING DEVICE FOR THROTTLE VALVES

Abstract: The invention relates to a sealing device for such throttle valves as comprise a valve housing with a valve seat and a pivotally mounted throttle member which may be pressed against the valve seat to bring about a sealing contact between two interacting sealing surfaces, one on the throttle member and the other in the valve housing and a sealing ring to be mounted in a slot in the valve. The invention is characterized in that the sealing ring (5) has a cross-section of a homogeneous, radially elongated body part (8) of considerable rigidity and resistance to radial deformation, that said body part at its head end (11) has a sealing surface (12) which is one of the two said sealing surfaces, and that from the "hip" part of the said homogeneous body part extend two essentially radial legs (14, 15), which form flanges of the sealing ring, said flanges being arranged to be pressed axially against the walls (18, 19) of said slot.

Description: TECHNICAL FIELD The invention relates to a sealing device for such throttle valves as comprise a valve housing with a valve seat and a pivotally movable throttle member which may be pressed against the valve seat to bring about a sealing contact between two interacting sealing surfaces, one on the throttle member and the other in the valve housing and a sealing ring to be mounted in a slot in the valve. BACKGROUND ART A sealing device of the type referred to in the preamble is known for instance from US-A-4284264. This known device comprises a homogeneous sealing ring intended to be mounted in a slot in the valve housing. The valve ring cross- section is an elongated flat body. The ring normally consists of metal and is considerably rigid with respect to deformation in the radial direction. The ring may, however, be bent aside by the throttle, when the throttle is pressed against the sealing ring. The inner, bluntly rounded edge of the ring constitutes the second sealing surface referred to above. A pair of spring washers are pressed against the two flat sides of the sealing ring, and between these two washers is formed the slot in which the sealing ring is mounted. The spring washers are in turn arranged between the valve housing and a mounting ring, gaskets being placed between the latter parts and the spring washers. Although this known device has several positive qualities compared to prior art and has signified a substantial improvement within this particular field, the two spring washers and the gaskets do constitute a complication. From for instance US-A-3080145 and US-A-4058290 the use of sealing washers with a U-shaped section is known for throttle valves with metallic sealing. In comparison with US-A-4284264 these have the advantage of being uncomplicated and not requiring separate gaskets. On the other hand, they have a low rigidity and resistance to radial deformation, which is unsatisfactory at least for some applications. DISCLOSURE OF THE INVENTION The object of the invention is to provide an improved sealing device for throttle valves of the type referred to in the preamble. In particular, an object is to eliminate the disadvantage listed above of prior art sealing devices for throttle valves. These and other objects may be accomplished by the sealing ring having a homogeneous, radially ablong body part of considerable rigidity and resistance to radial deformation, by the homogeneous body part having at its head end a sealing surface, constituting one of the two sealing surfaces mentioned in the preamble, and by two essentially radially directed legs extending from the "hip" portion of the homogeneous body, said legs forming flange-like extensions of the sealing ring, said extensions being intended to be pressed in the axial direction against the walls of the slot. Further advantages and characteristics of the invention will become apparent from the appended claims and the following description of a preferred embodiment. DESCRIPTION OF A PREFERRED EMBODIMENT In the following description reference will be made to the drawing figure, which shows an axial section of a throttle valve with a sealing device according to the invention. The valve comprises a valve housing 1 with a main part and a cover ring 3; a pivotally mounted throttle 4; and a sealing ring 5 in an annular slot 6 in the valve housing between the main part 2 and the cover ring 3. The throttle 4 has a sealing surface 7, which according to this embodiment is of the same configuration as in US-A-4284264. The sealing device according to the invention is not limited, however, to be used with this throttle configuration. The sealing ring 5 normally consists of stainless, acid-proof steel; an alternative is a very stiff plastic material. It is also conceivable that the ring 5 consists of a composite material or is composed of several materials. The ring 5 has a section which has a "creature"-resembling configuration with an elongated body part 8. The two sides 9, 10 of the body part 8 are completely flat and parallel. At that end 7 of the ring, which is directed toward the throttle member, the body part 8 is transfigurated directly into a "head" part 11 with a bluntly rounded surface 12, which constitutes the first sealing surface of the valve, against which the sealing surface 7 of the throttle 4 may be pressed. From the "hip" 13 of the body part 8, i.e. from the peripheral part of the homogeneous part of the ring 5, a pair of annular flanges 14, 15 extend radially, symmetrically outwards. In the section illustrated, the flanges 14 and 15 form the legs of the creature-resembling figure. On the legs 14, 15 there extend a pair of feet 16, 17, each being an outwardly pointing ledge on the respective flanges 14, 15. The feet/ledges 16, 17 are pressed by spring action of the legs/flanges 14, 15 against the walls 18 and 19, respectively, of the slot 6. The configuration of the ring 5 ensures the desired combination of radial rigidity, axial flexibility, and sealing ability against the two walls 18, 19 of the slot 6. The ring 5 by itself is stiff enough, which means that the two legs/flanges 14, 15 need not "brace their feet" 16, 17 against the bottom 20 of the slot 6. On the contrary, the slot 6 is so deep that the ring 5 may be displaced radially, i.e. the diameter of the slot 6 is greater than the outer diameter of the ring 5. The position of the ring 5 is thus adaptable to the throttle 4 when the valve is first closed. During this adaptation, the feet/ledges 16, 17 will slide against the parallel radial walls 18, 19 of the slot 6 without losing their sealing contact with them.

Claims: 1. Sealing device for such throttle valves as comprise a valve housing with a valve seat and a pivotally mounted throttle member, said throttle member being arranged to be pressed against the valve seat to bring about sealing between two interacting sealing surfaces, one on the throttle member and the other on the valve housing, and a sealing ring, said ring being arranged to be mounted in a slot in the valve, characterized in that the sealing ring (5) has a cross-section of a homogeneous, radially elongated body part (8) of considerable rigidity and resistance to radial deformation, that said body part at its head end (11) has a sealing surface (12) which is one of the two said sealing surfaces, and that from the "hip" part of the said homogeneous body part extend two essentially radial legs (14, 15), which form flanges of the sealing ring, said flanges being arranged to be pressed axially against the walls (18, 19) of said slot. 2. Sealing device according to claim 1, characterized in that the radial extension of the homogeneous body part is at least equal to that of the legs/flanges (14, 15). 3. Sealing device according to claim 1 or 2, characterized in that each of the two legs/flanges (14, 15) is provided with at least one encircling ledge (16, 17). 4. Sealing device according to any of the claims 1-3, characterized in that the ring is intended to be arranged in a slot (6) in the valve housing there to form the valve seat, that said first sealing surface is an inner, bluntly rounded edge of the ring, and that the two legs/flanges (14, 15) extend radially outwards from the homogeneous body part (8) of the ring 5. Sealing device according to claim 4, characterized in that the outer diameter of the slot in the valve housing is greater than that of the sealing ring.

Inventors: HUBERTSON, FOLKE HUBERT
Applicants: AKTIEBOLAGET SOMAS VENTILER
Application year: 1985
Main classification: F16K1
IPC codes: F16K1