Valve

A valve, includes a housing formed with a valve seat and having an inlet port and an outlet port; and a shut-off member positioned in a passageway between the inlet port and outlet port and so adjustable as to enable a separation of the inlet port and the outlet port from one another when seated on the valve seat, wherein the valve seat exhibits a seat surface which is so inclined in circumferential direction that intersections of diametrically opposed tangents constructed on the seat surface of the valve seat define an area.

BACKGROUND OF THE INVENTION 
The present invention generally relates to a valve, and in particular to a 
valve of a type having a housing formed with a valve seat and having an 
inlet port and an outlet port, and a shut-off member positioned in a 
passageway between the inlet port and outlet port and so adjustable as to 
enable a separation of the inlet port and the outlet port from one another 
when resting on the valve seat. 
A valve of this type is known e.g. from German Pat. No. 36 09 772 and in 
particular describes a valve seat which exhibits a seat surface which is 
so configured that the intersection of all tangents drawn on the seat 
surface form an imaginary cone, with the valve seat forming a slanted cut 
through this cone. Basically, the flow efficiency of such valves depends 
on the opening angle which influences the surface lines and thus the flow 
cross section which should be selected as large as possible in order to 
enable a substantially unhindered fluid passage. On the other hand, the 
dimensions of such valves, especially with regard to their structural 
length are standardized so that conventional seat surfaces cannot be 
configured for an optimum flow throughput. For example, a large opening 
cross section shaped to enhance flow dynamics cannot be realized because 
the standardized outer structural dimensions limit the opening angle of 
the cone. 
Determination of the flow efficiency is dependent besides on the flow 
velocity and rate of flow for pure liquids also on the same parameters for 
solids-laden liquids. Practice has shown that in this case the application 
of conventional valves is problematic heretofore. 
SUMMARY OF THE INVENTION 
It is thus an object of the present invention to provide an improved valve, 
obviating the afore-stated drawbacks. 
In particular, it is an object of the present invention to provide an 
improved valve which enables optimum flow efficiency conditions. 
These objects, and others which will become apparent hereinafter, are 
attained in accordance with the present invention, by providing a valve 
seat which exhibits a seat surface so inclined in circumferential 
direction that intersections of tangents, which are drawn on the seat 
surface of the valve seat and positioned in diametric opposite 
disposition, define an area. 
By so configuring the seat surface of the valve seat, the space dictated by 
the standard with respect to structural length can now be utilized for 
greatest possible opening cross section in the area of the valve seat. The 
angle of inclination of the seat surface of the valve seat with respect to 
the flow direction is dependent from the positional stability and the 
self-centering action of the shut-off member which is so configured as to 
match in the contact area the configuration of the seat surface, whereby 
it is immaterial whether the angle of inclination of the seat surface of 
the valve seat is the same or varies about the entire circumference with 
respect the vertical relative to the flow direction of the fluid. It is 
only relevant that the intersections of diametrically opposed tangents 
drawn on the seat surface, define an area, i.e. no common axis of rotation 
as conventionally taught heretofore. 
According to another embodiment of the present invention, the valve seat 
has a circumferential seat surface which extends at a right angle to the 
vertical with respect to the flow direction of the fluid. This has the 
particular advantage to keep the flow resistance very low. 
Apart of an improved operational capability especially in conjunction with 
a reduced flow resistance, a valve according to the present invention 
covers also a much wider range for application compared to conventional 
such valves. 
By matching the shut-off member in the contact area with the valve seat to 
the seat surface, a self-centering capability is attained by the shut-off 
member at the same time. Moreover, the closing force which is to be 
applied by a spindle upon the shut-off member in order to effect a fluid 
tightness can be low, resulting in an improved handling of the armature. 
A valve according to the present invention can be manufactured in a simple 
manner, as the seat surface can be made through a material removal process 
.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Throughout all the Figures, same or corresponding elements are generally 
indicated by same reference numerals. 
Turning now to the drawing, and in particular to FIG. 1, there is shown a 
fragmentary, schematic, perspective illustration of a valve according to 
the present invention, including a housing, generally designated by 
reference numeral 1 and formed with an inlet port 1a and an outlet port 11 
(FIG. 5). The inlet port 1a is formed with a valve seat, generally 
designated by reference numeral 2 which is slanted at an angle of e.g. 
45.degree., or in case of flap valves at an angle of 90.degree.. The valve 
seat 2 has a seat surface 3 which as depicted in FIGS. 3 and 4, extends at 
an angle .alpha. with respect to a vertical relative to the flow direction 
of fluid between the inlet port 1a and outlet port 11. 
As shown in FIG. 1, the seat surface 3 is so configured that all 
intersections of diametrically opposed tangents 5, 5a; 6, 6a; 7, 7a; 8, 
8a; 9, 9a; 10, 10a, drawn on the seat surface 3 circumscribe an area which 
is depicted in dashdot line 4. 
FIG. 2 shows an embodiment of a valve according to the present invention, 
in which the circumferential seat surface 3 extends at 90.degree. to a 
vertical with respect to the fluid flow direction so that cross sections 
of the seat surfaces 3 extend parallel to one another. 
FIG. 3 shows another embodiment of a valve according to the present 
invention in which the seat surface 3 of the valve seat 2 exhibits a same 
angle .alpha. about the entire circumference with respect to the vertical 
relative to the flow direction. The vertical may form at the same time the 
direction of action of a spindle 14 (FIG. 5) by which a shut-off member 13 
(FIG. 5) is forced against the seat surface 3. 
FIG. 4 shows still another embodiment of a valve according to the present 
invention, in which the angle .alpha. varies over the circumference of the 
seat surface 3. For ease of understanding, the angle of inclination in the 
region of the upper cross section of the seat surface 3 is denoted by 
reference character .alpha..sub.A while the angle of inclination in the 
region of the lower cross section of the seat surface 3 is denoted by 
reference character .alpha..sub.B. The magnitude of the respective angle 
is determined by operational conditions that depend i.a. from the type of 
fluid. 
As also indicated shown in FIGS. 2 to 4, the valve further includes a 
sleeve 12 positioned perpendicular to the inlet port 1a and outlet port 11 
for accommodating the shut-off member 13 and the spindle 14. 
FIG. 5 shows an embodiment of a valve in which the seat surface 3 of the 
valve seat 2 is so slanted as to form a different angle .alpha..sub.A and 
.alpha..sub.B in the upper and opposite lower regions with respect to the 
vertical. FIG. 5 also shows that the shut-off member 13 is suited to the 
valve seat 2 such that its side 13a that comes into contact with the seat 
surface 3 is so configured as to match the angles .alpha..sub.A and 
.alpha..sub.B of the seat surface 3 to thereby effect a self-centering 
action of the shut-off member 13 during closing operation. 
While the invention has been illustrated and described as embodied in a 
valve, it is not intended to be limited to the details shown since various 
modifications and structural changes may be made without departing in any 
way from the spirit of the present invention.