Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND. OF TI~E INVENTION
The invention herein relates to improved packing
saddle for use in gas and liquid contact apparatus. Saddles
of the type described herein have been in use in-the past.
However, the`design of these devices have some times hindered
their effective application in treating towers due to the
problems associated with the settling of the packing bed and
inordinate~amounts of liquids trapped in the tower due to
pooling or damming of liquid compositions therein.
One of the problems associated with saddles of the
type descr~ibed above is that they tend to engage with one
another in such a way that the effective surface area thereof
is reduced because certain surfaces of one saddle engage
with another so as to eliminatè any effective contact of
liquids and vapors passing in countercurrent through the
saddle bed. Another problem which has arisen is that the
beds after a period of use tend to settle. The effective
surface area for the entire bed may be reduced substantially,
the pressure drop may increase beyond acceptable limits, and
the settlèd bed may provide dams for chemicals and/or liquids
to pool or well such that the effective counterflow of the
liquids and vapors within the bed is reduced substantially.
The present invention contemplates utilization
of the saddles and design thereof in such a way that not only
is the settling problem virtually eliminated but the pooling
or ~elling of any li~uid is made virtually impossible due
to the effective separation provided by the design of the
saddle. Further, the numbèr of saddles required per cubic
foot may be greatly reduced over conventional saddles due in
part to the improved separation between saddles and the
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greater rigldity provided by the design as described below.
Excessive settling, having been eliminated, the effect of the
surface area provided is stabilized at that which is calcu-
lated for a particular volume of saddles in the tower. In
this regard, since the saddles are always separated from one
another and won't settle beyond a predictable and acceptable
limit, the pressure drop is rendered stable and remains sub-
stantially less than that with the saddles of the prior art
which tend to become tightly compacted.
It is therefore an object of the present invention
to provide a tower packing saddle which is economical to manu-
~acture and will provide sufficient separation from other adja-
cent packing saddles to eliminate the aforementioned problems.
It is another object of the present invention to
provide a tower packing saddle forming a stable bed when
deposited in a treatment tower.
It is another object of the present invention to
provide a tower packing saddle providing effective fluid and
vapor contacting surface without excessive pressure drop
within the tower.
It is still another object of the present invention
to provide a tower packing saddle which is not susceptible to
collapsing or flattening such that the packing bed will remain
relatively stable in volume and effective surface area for
fluid/vapor contacting.
SUMMARY OF THE INVENTION
A saddle packing element is provided which has a
general shape of a hollow torus. The torus has a convex surface
towards the toroidal axis and a concave surface away from the
toroidal axis with marginal edges lying in planes parallel
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to the toroidal plane. The element also includes a plurality
of substantially cylindrical drip points, with a portion of the
substantially cylindrical drip points being positioned along
the marginal edges to project beyond the marginal edges in
planes substantially parallel to the toroidal plane and with
the remaining portion of the substantially cylindrical drip
points being positioned along the ends of the saddle packing
element to project beyond the ends in planes substantially para-
llel to the toroidal plane. Some of the substantially cylin-
drical drip points extend from the concave surface of theelement and other substantially cylindrical drip points extend
rom the convex surface of the element.
For a better understanding of the present invention
together with other and further objects thereof, reference is
directed to the following description taken in connection with
the accompanying drawings, while its scope will be pointed out
in the appended claims.
DESCRIPTION OF THE DRAWINGS
Figure 1 shows a schematic drawing of a chemical
treatment tower with a section removed showing the disposition
of a bed of tower packing elements of the kind contemplated
in the present invention;
Figure 2 is a perspective view of a tower packing
saddle of the kind contemplated in the present invention;
Figure 3 is a top view of the saddle shown in
Figure 2;
Figure 4 is a side view of the saddle shown in
Figure 2;
Figure 5 is a sectional view taken along the line
5-5 of Figure 4;
Figure 6 is an end view of a saddle shown in
Figure 2, and
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Figure 7 is a variation illustrating a different
embodiment of the present invention.
Figure 8 is a cross-sectional view of the element
of the present invention illustrating a configuration for a
stamped element.
DESCRIPTION OF THE PREFERRED EMBODIMENT
I
Figure 1 generally shows a chemical treatment
t~wer 10 into which liquids L and vapors V are conducted in
count~rflow with each other. The tower 10 has a section
rQmoved to illustrate the general operation of the saddles
dQs~ribed herein and there is shown a supporting device or
~ray 11 into which a great plurality of the saddles designated
generally as 12 are disposed. The saddles are deposited in
the tray 11 randomly by merely dumping them in place and
roughly leveling the distribution by any suitable method.
The vapors V and liquids L flow in countercurrent relationship
with each other and will mix as the liquids flow over the various
surfaces of the packing saddle while the vapors engage with those
surfaces in accordance with the particular process.
In Figure 4, there is shown a side view of the
saddle resembling a side view of a semi-circular element or
semi-~ircular annulus. In reality, the general form of the
saddle is shown in Figure 2 and is an inner peripheral half
section of a hollow torus having three axes, a symmetrical
axis or central axis A, a transverse axis B and a cross-sectional
axis C. These a~es are perpendicular to one another and
generally describe the geometric relationship of the torus
~ith conventional descriptions.
The saddle 1~ has a plurality of substantially cylin-
drical drip points 13 of a selected length extending simultaneous-
ly or alternately along marginal edges 14 of the saddle. These
edges 14 shown also in Figures 3, 4 and 5 are parallel with each
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ot~. r and are in planes substantially parallel to a plane in-
cluding toroidal or transverse plane B. Another set of edges 15
are alternately disposed in the same plane which includes the
cross-sectional plane C of the torus. These edges 15 also
have substantially cylindrical drip points 16 of a selected
length which may be different from the length of the drip points
13 described above. The points 13 and 16 are evenly disposed
alon~ their respective edges 14 and 15 and on convex and concave
surfaces thereof, the convex surface being toward the toroidal
axis and the concave surface being away therefrom. It should be
understood that variations of spacing of the points is possible
and pxobable i required for different applications.
Figures 3 and 4 show the saddle with points 13 alter-
nately extending from convex and concave surfaces of each edge 14.
Figure 7 shows this variation in a fragmentary illustration
with edge 14' and points 13'.
The saddle 12 has a hole 17 having cross members 18
forming ribs of the saddle. These cross members strengthen
and give rigidity to the saddle as well as provide drip
points at their extreme ends shown more clearly in Figure 4
and in cross-section in Figure 5. Other ribs 19 are also in-
cluded but do not cross the opening of the hole 17. The hole
prevents any pooling or collection of chemical materials
sho~ld the saddle be disposed on some odd position. Further,
the hole 17 provides a passage for vapor flow which decreases
pressure drop across the bed.
It should be noted that the rib 18' in the hole
is asymmetrical. This asymmetry prevents the tight engage-
ment o two saddles and associated collection of fluids
adjacent surfaces which might be possible if two saddles
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en~ge one with the other. To illustrate, the rib 18' shown
in Figure 6 is of varied width since the outer edge 0 and the
inner edge I engaging with the saddle itself having offset
radii. The radii Rl and R2 are of different magnitude and
are offset by the distance D, the rib 18' is wider towards
the center 23 than at the ends 24. This provides asymmetry
which prevents tight engagement with other similarly formed
portions of other saddles so that pooling is virtually eliminated.
This principle is also illustrated in Figure 3
wherein R3 and R4 are radii of the differing magnitude offset
by distance D to form an asymmetric edge 15.
Another means to prevent pooling is to extend drip
points beyond the edges substantially so that as one saddle
engages with another, similarly shaped surfaces will not engage
flushly with`one another and therefore the pooling will be
virtually impossible since the fluids will flow between the
separating drip points which offset one surface from another.
Each of thè inner and outer surfaces of the saddle have been
designed so as to provide this protection by placing drip
points altèrnately on the surfaces.
It is essential to have the protection described
~bove since tha advantages of the invention herein are
hinged upon the fact that pooling and pressure drops are
reduced because the saddles do not settle and engage tightly
~ith one another. The saddles herein will react as any other
packing material and in time settle to some extent. However,
t~e ~ettling which occurs with the saddles of the present
invention is reduced to an amount which is predictable and
always maintains the surface area per cubic foot of packing
3~ material to within certain limits.
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In devices of the prior art, when eventual settling
occurred, it was possible to increase liquid entrapment;
reduce substantially the surface area available for the
counterflow of liquid and vapors; as well as increase the
pressure drop through the bed. In the present invention,
however, e~en if settling occurs, the drip points and exten-
sions theraof both outwardly and inwardly of the edges pre-
vent any surfaces from tightly engaging. This effectively
provides a saddle which has a predictable surface area per
uni~ volume and which will remain stable throughout its use-
~ul life.
}t should be understood that the saddle packing element
of the present invention may be utili~ed in a great many
processes. Fo~ example, differing combinations of liquid/vapor/
solid contacting, sewage treatment beds, chemical treatment
and heat exchange. Specific processes are evident from
recitation of the foregoing and it should be understood that
the processes are intended as exemplary recitations only.
The saddle packing elements of the present invention
may be made of a variety o~ materials. In certain types of
relatively low temperature operations, plastics of varying
~ypes may be used to fabricate the elements by injection
molding~ In high temperature operations, wherein a plastic
might deform or melt, a molded metal could be utilized. This
could be accoomplished by a powder injection and sintering
process. Other examples o~ possible processes could include
stamping ox die casting. Stamping would however change the
cross-sectional configuration slightly as illustrated in
~igure 8. The materials may include plastic of a suitable
3U material previQusly mentioned, to powdered metal, metal in
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liquid and sheet ,fox~ cer~mics and gla,ss; the mate~ial and
process being changed in accordance w~th the specific application
for the saddle. The sadale element ~llustrated in Figure 8 has
ribs 25 which are formed as depressions in the saddle. The ribs
25 shown in Figure 8 provide strength and may be contrasted with
the solid ribs 18 and 19 illustrated in Figure 5, which in the
former case are formed with a set of pressing dies, and in the
latter case are molded,
There has therefore been provided an improved saddle for
use in chemical treatment towers having the shape of a section
of a hollow torus with strengthening ribs and drip points therein
~or preventing engagement of one saddle element with another to
thereby eliminate welling of chemical liquids and providing a
stable and predictable pressure drop through the saddle material
per unit volume.
While there has been described what at present is con-
sidered to be the preferred embodiment of the present invention,
it will be obvious to those skilled in the art that various
changes and modifications may be made therein without departing
from the invention. It is intended in the appended claims to
cover any such modifications and changes as fall within the true
spirit of the scope of the invention.
