Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to valves in general,
and more particularly to i~provements in bodies or housings for
shutoff valves. Still more particularly, the invention relates
to improvements in housings for shutoff valves, especially gate
valves, wherein sections which preferably constitute forgings
are bonded to each other by welded seams.
It is already known to assemble the housing for a gate
valve of several sections which are produced by forging and are
assembled in part by resorting to a welding technique. For
example, the housing may comprise an upper section or bonnet and
a lower section which is assembled of two substantially mirror
symmetrical halves. The two halves are welded to each other,
and the two sections are riveted or bolted to each other. The
seam of weldant which connects the two halves of the lower
section is located in the central plane of the reciprocable
gate. The bonnet accommodates the customary components of the
gate valve. The tubular portions of the lower section are made
by forging and serve to connect the housing with the adjacent
portions of a pipeline~ Reference may be had to German Utility
Model No. 1,706,081 wherein the lower section has a top flange
which can be attached to the lower end of the bonnet.
German Patent No. 1,114,683 discloses a modified valve
housing which exhibits the advantage that its component parts
can be more readily welded to each other, i.e., that such parts
can be more readily welded in existing machines. However, the
patented housing is not a forging but rather a body which is
assembled and made almost exclusively by welding.
A drawback of the above outlined conventional housings
is that they lack adequate guide means for the gate. As a rule,
or at least in many gate valves, the gate is guided exclusively
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by the bonnet which is undesirable in many instances because
the stem or spindle for the gate is subjected to excessive
stresses. It is also known to subject an assembled valve
housing to a secondary treatment which involves the installation
of guide means for the gate in the lower section of the housing.
In many instances, the subsequently installed guide means
includes strips which are secured to the lower section by welding.
This involves additional expenses and is likely to lead to
inaccuracies which can be eliminated by resorting to a further
treatment, e.g., to removal of material in a lathe, a milling
machine ox a turning machine.
In accordance with the invention, those portions of
the halves of the lower section of the valve body or housing
which are adjacent to the welded seam have a circular outline,
and the surfaces bounding the guide groove for the gate are
integrated into the halves of the lower section. Such surfaces
are portions of circular surfaces whose centers are located on
an axis 'including the center of curvature of the seam. The just
defined construction exhibits the important advantage that the
problem of properly guiding the gate in the interior of the
lower section of the valve housing is solved in a simple,
reliable and inexpensive manner. The halves of the lower
section of the housing preferably constitute forgings, and the
lower section is preferabl~ welded to the other section or
bonnet of the housing.
The novel features which are considered as
characteristic of the invention are set forth in particular in
the appended claims. The improved valve housing itself, however,
both as to its construction and the mode of assembling the same,
together with additional features and advantages thereof, will
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be best understood upon perusal of the following detailed
description of certain specific embodiments with reference to
the accompanying drawing.
Figure 1 is a fragmentary axial sectional view of a
valve housing which embodies the invention, a portion of the
bonnet being indicated by phantom lines;
Figure 2 is a horizontal sectional view as seen in
the direction of arrows from the line II-II of Figure l; and
Figure 3 is a sectional view as seen in the direction
of arrows from the line III-III of Figure 1.
The drawing shows the housing of a shutoff valve,
namely, of a gate valve having a lower section which is assembled
of two mirror symmetrical halves 1, 2 and an upper section or
bonnet 10 a portion of which is denoted by phantom lines (see
Figures 1 and 3). The bonnet 10 and the halves 1, ~ are steel
forgings. A first welded seam 3 permanently connects the halves
1, 2 to each other, and a second welded seam 11 connects the
circular or oval upper end face of the lower section to the
complementary underside of the bonnet 10.
The halves 1 and 2 of the lower section of the valve
housing have finished surfaces 4 and 5 which define the seat
for the gate, not shown. Furthermore, the halves 1, 2 have
finished surfaces 6, 7 defining a guide groove 12 for the wedge
gate, not shown. The tubular portions 8, 9 of the halves 1, 2
can be connected with the adjacent components of a pipe line,
not shown.
FIG. 2 shows that the planes of the surfaces 6, 7
bounding the guide groove 12 are offset relative to and flank
the plane of the seam 3. These planes may be parallel to each
other, or the planes of the surfaces 6, 7 can be mirror
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symmetrical to each other with reference to the plane of the
seam 3, depending on the design of the gate.
Referring to FIG. 3, it will be seen that the center
of curvature 3A of the circular seam 3 is located on an axis
which extends at right angles to the plane of the drawing. The
surfaces 6 and 7 constitute portions of circular surfaces whose
centers are also located on the just mentioned axis. This
simplifies the manufacture and reduces the cost of the housing.
The axis passing through the center of curvature 3A is parallel
to the common axis of the tubular portions 8 and 9. Those
portions of the halves 1 and 2 which are adjacent to the seam 3
have a circular outline and the seam 3 has a substantially
triangular cross-sectional configuration.
The improved valve housing exhibits the aforementioned
advantage that the gate can be properly guided in the lower
section of the housing. The guide means includes the groove 12,
and more particularly the surfaces 6 and 7 which flank the
` groove. The centers of circular surfaces which include the- surfaces 6 and 7 are located on the axis which also includes
the center of curvature of the seam 3. This greatly reduces the
manufacturing cost of the section including the halves 1 and 2.
Another advantage of the improved housing is that the
surfaces 6, 7 can be formed by forging simultaneously with
forging of the surfaces 4 and 5, i.e., with the finishing of the
seat for the gate which latter is preferably but need not
necessarily be a wedge~ This renders it possible to finish the
edge faces for the seam 3 and the surfaces 6, 7 (and also the
surfaces 4, 5) during a single insertion into a turning or
another suitable finishing machine. Moreover, such treatment
can be carried out by resorting to a relatively simple and
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36~
inexpensive machine. The same holds true for the machine which
is used to make the seam 11 and/or 3. The section including
the halves 1 and 2 is ready for attachment to the section or
bonnet 10 as soon as the making of the seam 3 is completed, i.e.,
there is no need for aftertreatment or secondary treatment of
the interior of the lower section subsequent to bonding of the
halves 1 and 2 to each other.
Still another advantage of the improved housing is
that the guide means (6, 7, 12) for the gate is located in the
interior of the lower section. This reduces the stresses upon
the gate and its spindle or stem. Also, the stresses which are
applied to the gate can be transmitted directly to the housing,
i.e., along the shortest path possible.
All of the aforementioned advantages are attributable
to the features which are characteristic of the improved valve
housing and which can be achieved without any further treatment
and/or without resort to any additional apparatus, units or
devices.
