Note: Descriptions are shown in the official language in which they were submitted.
595~6
" AXIAL MULTIPORT ROTARY VALVE "
FIELD OF THE INVENTION
This invention relates to apparatus for transferring a plurality of
fJuid streams amon~ different locations. More particularly, it relates to a
unitary multiport rotary valve which is capable of accomplishing the
simultaneous interconnection of a plurality of conduits in accordance with a
predetermined periodic sequence.
U.S. Patents 3,040,777 (Carson et al.) and 3,422,848 (Liebman et
al.) describe multiport rotary disc valves which have been used in practicing
the process of U.S. Patent 2,985,589 (Broughton et al.), which is described
herein, and other similar processes. However, in the practice of a process
10~ such as disclosed in U.S. Patent 4,402,832 (Gerhold), which is described below,
the valve of these references cannot be utilized. A valve having utility similarto the apparatus o:E Carson and Liebman is disclosed in U.S. Patent 3,192,954
(Gerhold et al.~; this valve employes a cylindrical rotor within a surrounding
stator, as exemplified by Figure 8.
RIEF SUMMARY OF THE INVENTION
This invention relates to a unitary axial multiport rotary valve
useful in transferring a plurality of different fluid streams among different
locations in accordance with a previously determined cycle. The fluid streams
are contained in conduits which are interconnected by means of the valve.
Any co~nduit communicates with no more than one other conduit at any one
cycle step, or valve index position. The conduits to be interconnected are
attached to a hollow stationary body, or stator assembly which is comprised of
~2595i~
three sections, or elements, each oI which is cylindricai in form.
There are fluid flow channels in a rotating body, or rotor assembly,
which is located inside the stator assembly and configured in a manner similar
to it. The rotor assembly assumes various positions according to the cycle
5 steps and distributes fluid flowing into and out of the valve, by means of the
conduits, in a difIerent manner in each cycle s$ep. There are annular spaces,
or annular volumes, between the rotor and stator assemblies which contain
sealing means for prevention of leakage and definition of flow passages.
There are many instances in which it is necessary to route a fluid
10 stream to one location for a period of time, then to another location for a
period of time, and so forth for multiple locations. This relatively simple
problem of routing a single fluid stream to various destinations in a previously
determined cycle or periodic sequence is easily accomplished with one or more
devices such as a multiport rotary plug valve. When it is necessary to
15 simultaneously route more than a single fluid stream to various destinations, it
is highly desirable to use a single device rather than numerous individual
valves, as discussed in the above-mentioned Carson patent ~3,040,777). An
axial multiport rotary valve is such a device.
It is among the objects of this invention to provide unitary
20 mechanical valve apparatus for simultaneously accomplishing the interconnec-
tion of a plurality of conduits in accordance with a previously determined
cycle, where any conduit cornmunicates with no more than one other conduit
at any one valve index position. It is al~o among the objectives to provide a
valve smaller in physical size and having ~ewer maintenance requirements than
25 prior art valves. A broad embodiment of the invention is a valve comprising:
ta) a stator assembly having a hollow interior and being comprised of a central
element, a first end element5 and a second end element, each of said elements
having a cylindrical f orm; ~b) a rotor assembly comprised of a central
~2~95~
element, a first end element, and a second end element, each of said elements
having a cylindrical form, which rotor assembly is located substantially inside
the hollow interior of the stator assembly such that a first annular space is
formed between said first rotor end element and said first stator end element3
5 a second annular space is formed between said second rotor end element and
said second stator end element, and a central annular space is formed between
said central rotor element and said central stator element, which rotor
assembly rotates about an axis of rotation to various valve index positions in
accordance with said previously determined cycle, where said axis is the
10 longitudinai axis of both the rotor and stator assemblies, and which rotor
assembly has a plurality oI interior channels communicating between fluid
passages formed in said annular spaces in order to transfer fluids between said
fluid passages; (c) a plurality of nozzles for connection of said conduits to the
valve, the nozzles being attached $o the stator assembly and providing fluid
15 paths between the conduits and said annular spaces inside the stator assembly;
and (d) sealing means in said annular spaces for prevention of external
leakage, definition of said fluid passages, and prevention of intermixing of
fluids flowing through the valve, such that different pairs of nozzles
communicate at each valve index position, in accordance with said previously
20 determined cycle, and such that fluid supplied by a nozzle passes through, in
sequence, one of said annular space fluid passages, a rotor assembly channel,
and another of said annular space fluid passages before entering another
nozzle to flow out of the valve.
Among the unique features of particular embodiments of the
25 present invention are fluid flow paths denoted herein as tie pipes and central
stator element passageways~ These fluid flow paths enhance the flexibility of
an axial multiport rotary valve, so that it can accommodate various process
arrangements requiring interconnection of a plurality of conduits. Tie pipes
~2~9S ~6
communicate between annular volumes formed between rotor and stator end
eiements. Central stator element passageways permit fluid to enter the valve
through a nozzle attached to the stator central element and exit through
another nozzle attached ~o the sta~or central element, thus by-passing the end
elements oE the valve
BACKGROUND OF THE INV~NTION
The separation of various substances through selective absorption
using a simulated moving bed of adsorbent is an example of a process in which
an axial multiport rotary valve is useful. Simulation of a moving adsorbent
bed is described in U.S. Patent 2,985,~89 (Broughton et al.), which is
mentioned above. Figure 11 depicts process and apparatus of this patent. In
accomplishing this simulation, it is necessary to connect a ~eed stream to a
series of beds in sequence, first to bed no. 1, then to bed no. 2, and so forth for
numerous beds, the number of beds often being between 12 and 24. These beds
may be considered to be portions of a single large bed whose movement is
simulated. Each time the feed stream destination is changed, it is also
necessary to change the destinations ~or origins~ of at least three other
streams, which may be streams entering the beds, such as the feed stream, or
leaving the beds. The moving bed simulation may be simply described as
dividing the bed into a series of fixed beds and moving the points of
in~roducing and withdrawing liquid streams past the series of fixed beds
instead of moving the beds past the introduction and withdrawal points. A
rotary valve used in the Broughton process may be described as accomplishing
the simultaneous interconnection of two separate groups of conduits.
There are many different process requirements in moving bed
simulation processes, resulting in different flow schemes and thus variations inrotary valve arrangement. For example9 in addition to the four basic streams
~2~3S~;
described in aroughton (2,985,589), i~ may be desirable to utilize one or more
streams to purge, or flush, a pipeline or pipelines. A ~lush stream is used to
prevent undesirable mixing of components. The flush substance is chosen to be
one which is not undesirable for mixing with either main stream, that being
5 purged or that which enters the pipeline after flushing is completed. U.S.
Patent 3,201,491 (Stine et al.) may be consulted for information on flushing
lines as applied to the process of Broughton (2,985,589). It may be desirable to
pass fluid through a bed or beds in the reverse direction from normal flow.
This is commonly known as backflushing, a subject treated in U.S. Patent
10 4,319~929 (Fickel). Other applications for various arrangements of multiport
rotary disc valves may be seen in U.S. Patents 4,313,015 (Brough~on);
4,157,267 (Odawara et al.); 4,182,633 (Ishikawa et al.); and 4,409,033 (J eRoy).
Multiport rotary disc valves of the general arrangement shown in
the above-mentioned patents (3,040,777 and 3,422,848) have been fabricated in various
15 sizes up to valves utilizin~ 4-l/2 foot (1.37m) diarneter rotors. These valves
have seven concentric circumferential grooves, or tracks, and 24 ports spaced
around the periphery of the stator. A single valve of this size wei~hs approxi-
mately 26,000 pounds, has an overal1 height of about 15 feet ~4.6m), and
occupies a plan area of approximately 8-l/2 by 8-1/2 feet (2,6 by 2.6 m), These
figures do not include a separate hydra~ power unit used with the hydraulically
driven actuator mounted on the valve proper, It can be appreciated that it is
desirable to use apparatus of less bulk and weight to accomplish the same
functions; the present invention provides such a smaller rotary valve. It is
capable of accomplishing the interconnection of conduits in two groups and has
further utility as discussed in the paragraphs immedia~ely following.
While the multiport rotary disc valve of Carson (3,040,777)
provided a satisfactory valve design for the simultaneous interconnection of
two independent groups of conduits such that each conduit of the first group
1;~59S~6
could be brought into individual communication with every conduit of the
second group, it is not suitable when three groups of conduits must be
simultaneously interconnected in the same manner. Upon reference to
Broughton (2,985,589), it can be seen that there are only two groups of
conduits which need to be interconnected when the arrangement of the
drawing of that patent is utilized. One group consists of the conduits which
provide the flows entering and leaving the simulated moving bed adsorbent
system, that is, the flows which are switched among the beds, such as the feed
stream. A second group consists of the conduits associated with the individual
beds, that is, which supply and remove fluid from the beds, one conduit being
connected between each two beds. It is to be noted that each conduit of the
second group serves that dual function of supply and removal, so that it is
unnecessary to provide conduits for supplying fluid separate from those for
removing fluid.
When it is necessary to simultaneously interconnect conduits of
three different groups of conduits in accordance with a previously determined
cycle, the apparatus of the present invention may be used. An example of a
process involving three conduit groups may be found in U.S. Patent 4,402,832
(Gerhold), which is described below. As mentioned above, it is highly desirable
to use a single device to do so, thereby avoiding the o~vious problems
associated with numerous separate ~alves which must be simultaneously
actuated.
BRIEF DESCRIPllON OF THE DRAWINGS
, .
FIGURE 1 deplcts in schematic fcrm six separation zones, or units,
with two different fluid flow arrangements, where each arrangement is that
associated with a single step of the process of U.S. Patent 4,402,832 (Gerhold). FIGURE 2 is a schematic representation of a valve and conduits to
--6-
~2595'~
be interconnected by its use as required by the process of FIGURE 1.
FIGURE 3 depicts an axial multiport rotary valve with tie pipes
and with labels referring to the process of FIGURE 1. Section arrows 35 show
how FIGURE 8 is taken. Certain details are omitted for the sake of drawing
5 convenience.
FIGURE 4 is a partial sectional view of the left hand end of the
valve of FIGURE 3, including a portion of a stator end element, a portion of a
rotor end element, and a seal ring follower. Certain details are omitted for
the sake of drawing convenience.
FIGURE 5 depicts a rotating seal ring with O-rings omitted.
FIGURE 6 is a partial sectional view of the valve of FIGURE 3,
including portions of rotor and stator end elements and central elements.
Certain details are omitted for the sake of drawing convenience.
FIGURE 7 shows a stator central element with por$ions of the
15 stator end elements and with central seal elements in place on the central
element. This is configured for use in the valve of FIGURE 3.
FlCiURE 8 is a section, taken as shown in FIGURE 3, of the central
elements used in the valve of FIGURE 3. Two process steps are shown.
FIGURE 9 is a section view of a central seal element taken as
20 shown by section arrows 9 in FIGURE 10.
- FIGURE 10 is a top view of the central seal element of FIGURE 9.
FIGUR~ 11 is a schematic depicting the Broughton process (U.S.
Patent 2,985,589), showing a vessel containing a plurality of beds with conduits
connecting the beds and an axial rnultiport rotary valve and conduits for
25 streams entering and leaving the process.
FI(;7JRE 12 depicts an axial multiport rotary valve with certain
nozzles labeled to refer to the process of FIGURE 11 (the Broughton process)
and depicting conduit arrangement in the same manner as FIGURE 11. Since
~L~59~
the valve is otherwise identicaJ to that of FIGURE 3, valve component
reference numbers have been omitted.
DETAILED DESCRIPTION OF THE !NVENT~ON
Following is a descrlp~ion of the embodiment of the invention
shown in FIGURES 1 through 10. It is not intended that such description be
construed as ~imiting the scope of the invention in any way; the description of
this example is merely a convenient rneans to become familiar with the
invention. The eJements of the invention may be arranged to form other
embodiments and more or fewer conduits than shown in these drawings may be
accommodated.
FIGURE I depicts an exemplary processing system which will be
used in describlng the invention. This processing system is described fully in
the previously mentioned IJ.S. Patent 4,402,832 ~Gerhold3 and it is only
necessary to describe herein, in order to understand ~he present invention, the
required fluid flow arrangement and cycle, further details being available from
the patent. As depicted in FIGUR~ 1, there are six individual separation
zones, or units, denoted by reference numbers 1 through 6. There are conduits
carrying four fluid streams, two streams entering the processing system and
two leaving the processing system (as denoted by the arrows), labeled feed,
extract, desorbent, and raffinate. These four streams may be called process
flows or process streams. The manner of interconnection of the separation
units by means of conduits carrying several fluid streams varies in order to
simulate movement of the units in a direction cocurrent with the fluid flow.
There are six steps in a complete cycle, i.e., six different inter-
connection arrangements to be accomplished by the valve. Two of the steps
are shown in FIGURE 1 and from these two, the other four steps are easily
understood. As the process, or valveg is indexed through each step of the
1~595;~
cycle, each of the labeled streams is moved to a different separation unit.
The streams may be visualized to move toward the le~t in FIGURE l in order
to simulate movement of the separation units to the right. During step l, feed
is provided to unit l, impure extract is removed from unit l and flows to unit
5 2, dilute extract is recycled from the outJet to the inlet of unit 3, desorbent is
provided to unit 4, dilute raffinate flows from the bottom of unit 4 to the top
of unit 5, and impure raffinate is recycled at unit 6, as shown in step 1 of
FIGURE l. At the end of the step l time period, the valve indexes, or rotates,
to its step 2 position, in which feed is routed to unit 6, impure extrac~ is
10 removed from unit 6 and routed to unit l, and so forth, as shown in step 2 of
FIGURE l. In step 2, abbreviations are used, such as IE for impure extract;
their meanings are made clear by reference to the labels of step l, referring
to the first letters of the words. It can now be understood that in step 3, feed
will be routed to unit S and corresponding changes will be made in the origins
1.~ and destinations of the other streams. During step 6, feed will be routed to
unit 2 and upon the next step, return to unit l, the cycle being repeated
indefinitely.
FIGURE 2 depicts the valve as a box and shows the streams of
FIGVRE l as arrows entering and leaving the box. Each arrow may be viewed
20 as a conduit, or pipeline, the direction of flow being as shown. Thus there are
six conduits conveylng fluid to the valve, one communicating with the outlet
of each separation unit and six conduits conveying fluid away from the valve,
one communicating with the inlet of each separation unit. In addition1 there
are four conduits to accommodate the process flows discussed above, labeled
25 with F for feed, etc. The conduits connected to ~he valve may be placed in
three groups: process flows, unit ins, and unit outs.
Referring to FIGURE 3, a hollow stator assembly is comprised of
central element ll, end element 12, and end element 13. In this embodiment
~L2595 ~
of the invention, the end elements of the stator assembly are bolted to the
central element (bolts not shown for drawing convenience). A rotor assembly,
also comprised o a central element and two end elements is located
substantially within the hollow interior of the stator assembly. Either
5 assembly, rotor or stator, may be separable into parts independent of the
terminology used herein; the use of the word elements is not intended to
convey that the assembly must be separable into the three elements described.
Each of the rotor and stator elements is cylindrical in form. In thls
embodiment, the central elements are larger in diameter than the en~
10 elements; this is not necessarily the case in other embodiments. Size is
determined by the number of fluid streams passing through the valve, their
routing, and their rnagnitude, as well as by mechanical considerations. Only a
portion of each rotor end element is shown in FIGURE 3. Rotor end element
17 projects out of stator end element 12 and rotor end element 1~ projects out
15 of stator end element 13. Attached to the rotor are shafts denoted by 19 and
21, and the rotor ls suppor~ed in bearing assemblies 22 and 23. Means for
rotating the rotor assembly about an axis of rotation are denoted by reference
figure 20. The axis of rotation is the extended center line of shafts 19 and 21,
or the longitudinal axis of both assemblies. In this particular example, the
20 rotor is rotated in 60 increments, with any one of six rest positions of the
rotor being defined as a valve index position and representing the rotor
position at, or during, a single cycle step. Such means for indexing a shaf$, or
rotating it in increments of usually less than a full rotation, are well known
and may be characterized broadly as hydraulic, electrical, or electro-
25 mechanical. An example of means for rotating may be ~ound in U.S. Patent2,948,166 (Purse et al.)
Each stator end element has a flange 14, to which seal ring
followers 15 are attached by bolts 16. The function of the seal ring followers
-10-
1~5~
is discussed below. A plurality of nozzles such as 26 and 27 are attached to
the stator and provide fluid passa~es between the interior of the stator and
conduits which are connected to the nozzles. The nozzles may be divided into
four sets depending on their location on the stator assembly. Nozzle 26 is
5 representative of nozzles in a first set located on one stator end assembly, in
this case, the end element shown on the left. Nozzle 28 is representative of a
second set of nozzles located on another stator end element, depicted on the
right in FIGURE 3. A third set of nozzles is attached to the central stator
element adjacent to the left stator end element and Includes nozzle 27.
10 Nozzle 29 is representative of a fourth set of nozzJes attached to the central
stator element adjacent to the right s$ator end element. Stator tie pipe 31
connects nozzles 36 and 7~1 providing a fluid passage between those nozzles.
Likewise, stator tie pipe 30 provides a passage for the flow of fluid between
noz~les 26 and 64. Section arrows 35 show the manner in which the views of
15 FIGURE 8 are taken.
The labels of FIGURE 3 are the same as those of FIGURES 1, 2,
and 8. The letters (those without numbers) correspond with the abbreviations
of FIGURES 1 and 2, e.~., F denotes the feed stream. All of the conduits
discussed in connection with FIGURES 1 and 2, sixteen in number, are
20 connected to the stator assembly by means of nozzles, though not all of the
nozzles are shown in FIGURE 3. There are six nozzles in the third set, which
includes nozzle 27. Two of the nozzles of the third set are not visible in
FIGURE 3; they are located in positions on the back of the stator central
element. The nozzles of the third set are equally spaced around the stator
25 central element, 60 apar~ and their center lines are all in a single plane
normal to the axis of rotation. The nozzles of the fourth set are arranged in a
manner similar to the third set. Only three fourth set nozzles can be seen in
FIGURE 3.
~L25~35 t~
Again referring to FiGURES 1, 3, and 8, the labels IT through 6T
and 1~ through 6B refer to a particular separation unit and a particular
conduit attached to that unit. For example, IT indicates that the conduit
attached to that nozzle communicates between that nozzle and the top o~
5 separation unit 1 and 3B indicates ~hat the conduit attached to that nozzle
communicates between that nozzle and the bottom of separation unit 3. The
nomenclature "top" and "bottom" is used for convenience only, because in
FIGURE 1, the inlets to the separation units are shown at the top of the
drawing.
Now referring to FIGURE 4, the applicable reference numbers of
FIGURE 3 are used. Rotor end element 17 is located substantially inside
stator end element 12. Nozzles 26 and 36 of FIGURE 3 are shown in FIGURE
4. Two interior channels 37 and 38 are shown in rotor end element 17. There
are two additional channels (not shown) in rotor element 17 and all four
15 channels, which comprise a first group, extend into the rotor central element
(which is not shown in FIGURE 4). Channel 37 communicates with nozzle 26
and channel 38 communicates with nozzle 36. Stator end element 12 has a
larger inside diameter than the outside diameter of rotor end element 17, thus
forming an annular space, or annular volume, between the elements. As shown
20 in FIGURE 4, this annular space is filled with seal rings. In contact with the
portion of seal ring follower lS which projects into the annular ~rolume is an
end seal ring 39. Adjacent to end seal ring 39 is a rotating seal ring 40 and
next to that is a stationary seal ring 43. Another rotating seal rin~ 40 is
adjacent to stationary seal ring 43 on the other side. FIGURE 5 shows a single
25 rotating seal ring 40. In a similar manner, an annular space is formed between
rotor end element 18 and stator end elernent 13 (FIGURE 3) and also between
the rotor central element and the stator central element.
All o~ the nozzles communicate with the annular spaces between
~2S9S ~
the rotor assembly and the stator assembly. The seal rings are means by which
fluid passages in the end element annular spaces are defined, intermixing of
fJuids in the annular spaces is prevented, and external leakage i~ prevented.
For example, fluid flowing in channel 37 and nozzle 26 is separated from fluid
in channel 38 and nozzle 36 by the seal rings. Rotating seal ring 40 extends
circumferentially around the rotor end element and is configured such that
annular passa~e 44 is formed in a portion of the annular space between the
stator and rotor end elements, between the inside wall of the stator end
element and the outside surface of ring 40. FIGURE 5 shows an entire seal
ring. Note that O-rings 52 are omitted from the inner surface of the seal rin8
depicted in FIGURE 5. An aperture 45 (FIGURE 5) in seal ring 40 is aligned
with channel 37 and permits fluid to flow between channel 37 and annular
passage 44. Since annuJar passage 44 is circumferential, extending 360
around the rotor assembly, the passage is always in communication with nozzle
26, thereby nozzle 26 and channel 37 are always in communication. Similarly,
each of the other channels of the left rotor end element are always in
communication with a particular nozzle attached to the left rotor end element
(nozzles 32, 34 and 36). An O-ring 52 is located on each side of the ring 40, asshown in FIGURE 4, to prevent fluid from the aperture 45 and the annular
passage 44 from flowing in a longitudinal direction parallel to the axis of
rotation along the outside surface of the rotor end element and the inside
surface of the ring 40.
End seal ring 39 does not rotate and is held in place by means of a
set screw 8 inserted through the wall of the stator element and projecting into
cavity 42. Rotating seal rings 40 are attached $o the rotor and rotate with it.
Attachment is accomplished by means of a groove 41 (see FIGURE 5) in each
rotating seal ring 40. There is a tongue (not shown) whlch matches the grooves
on the end element for each seal ring 40. When tongue and groove are
5 ~i
en~aged, the seal ring is lock~d in place. Stationary seal ring 43 is prevented
from rotating by means of a se~ screw in the same manner as end seal ring 39.
O-rings 52 preven. fluid leakage between the rotor end element and rotatin~
seal rings 40, as described above, and between the stator end element and the
5 stationary seal rings 43 or end seal ring 39, in the same manner. Leakage does
occur between the wall of the s~ator and rotating seal ring 4û. This leakage
lubricates and is contained at seal interface 53 which extends 360 around the
rotor end element and is in a plane perpendicular to the axis of rotation. The
sealing surfaces at interface 53 may be any of the well-known materials used
10 in applications where a stationary seal face bears against a rotating seal face.
For example, a common pair of seal face materials are carbon and tungsten.
Seal ring 40 may be fabricated entirely of tungsten and rings 39 and 43 may be
fabricated entirely of carbon, or carbon and tun~sten may be applied to other
base ring materials solely to form the sealing surfaces at interface 53.
The cornplete arrangement of the left rotor end element may now
be understood. A seal ring 40 is located at each of the four nozzles of stator
end element 12. Between the rotating seal rlngs are located stationary seal
rings 43. There are three stationary rings at each end element. At each end
of the annular space formed by the left end elements is an end seal ring 39.
20 The rotor end element shown on the right in FIGURE 3 is arranged in the same
manner. Only one end of the annular space between end elements can be seen
in FIGURE 4. The other end is shown in FIGURE 6, where it can be seen that
the assembly of seal rings is retained by a shoulder on the rotor which is
adjacent to rotor sleeve 51. At the other end, the assembly of rings is held in
25 place by seal follower 15 ~FI~URE 4). Also, sealing force is applied to the
sealing surface interfaces by means of seal follower 15. A spring 25 is
provided at each bolt 16. Spacers 24 enable spring 25 to be compressed by
turning bolts 16 and, therefore, urge seal follower 15 toward the stator central
--14_
~2~95i~S
element, thereby providing sealing force.
FIGURE 6 shows the other end of stator element 12 and rotor end
element 17 and al~o a portion of stator central element 11 and a portion of the
rotor central element 46. Rotor central element 46 and rotor end element 17
5 are fastened together by means of bolts such as 47. ~otor sleeve 51 provides
spacing between stator element 12 and rotor element 17 and serves as a
bearing. Channels 37 and 38 communicate with an annular space between
rotor central element 46 and stator central element 11. Fluid flows between
nozzle 27 and channel 37 and nozzle 50 and channel 3~. Definition of fluid
10 passages and prevention of intermixing, in the central element annular space,
of these streams and others is accomplished by means of rotor seal elements
48. FIGURE 9 shows a section view of a single rotor seal element 48.
FIGURE 10 shows a top view, including the sealing surface, of rotor seal
element 48. FIGURE 7 depicts rotor central element 46 with several seal
15 elements 48.
The arrangement of the left portion of the valve of ~IGURE 3 is
described in detail; the right portion of the valve, comprising rotor and stator
end elements and right hand portions of the rotor and stator central element is
similar. FIGURES 4 and 6 in a mirror image configuration would depict the
right hand portion of the valve.
FIGURES 6, 7, 9, and 10 should be consulted for the following
explanation. A rotor seal element is loca~ed at the central element end of
each channel and at each end of each passageway (discussed below) in the
rotor central assembly. These seal elements define fluid passages and prevent
2~ intermixing of fluids in the central annular space. In this embodiment, there
are twelve rotor seal elements 48, eight for channels and four for
passageways. Reference figure 60 denotes the fluid passage. A length of
cylindrical conduit which comprises an elongated cylindrical portion of a rotor
12595,~
seal element 48 is located within a portion of channel 37. That portion of
channel 37 has a larger diameter than other portions of the channel such that a
shoulder is formed to retain spring 49 (FIGURE 6)._ Each rotor seal element is
provided with O-ring 59 around its outer circumference ~o prevent leakage
5 between the annular space and the wall of the channel. A curved rectangular
plate portion is attached to the cylindrical portion and is covered by rotor seal
element seat 56 (FIGURE 9). Spring 49 presses sealing face 55 against the
inner surface of stator central element 11, which is smooth and polished to
prevent leakage at the inside wall of the stator central element. Sealing face
10 55 is a portivn of rotor seal element seat 56, which is formed of a soft
elastomeric material. Rotor seal element seat 56 is held in place by means of
two retainers 57 and four screws 58. Rotation of the rotor assembly results in
wear at surface 55, as a result of the movement of the surface around the
interior wall of the stator central element. Spring 49 provides sealing force
15 and will maintain it as wear occurs, but periodically rotor element seat 56 will
need to be replaced. The movement cf rotor seal element 48 in the enlarged
portion of channel 37 is relatively small and such rnovement does not affect
the sea~ing ability oi O-ring 59.
Referring now to FIGURES 4 and 6, it can be seen that channels 37
20 and 38 are comprised of three sections. One section is perpendicular to the
axis of rotation and located wholly in the rotor end element. One section is
parallel to the axis and located both in the rotor end element and the rotor
central element. One section is perpendicular to the axis and located wholly
within the rotor central element. The other six channels (for a total of eight
25 channels) of this embodiment are similar.
In FIGURE 8, all of the nozzles of sets 3 and 4 are shown. Nozzles
lB through 6B are shown in section and are uniformly spaced every 60 around
stator central element 11 in a single plane. lT through 6T, the nozzles
12S9S ~
connected by ccnduits to the tops of the separation zones, or units, as shown in
FIGURE 1 are arranged in a similar manner but are offset by 30 from the
third set of nozzl~s. ln this embodiment, the 30 offset exists only for reasons
of convenience in connecting conduits to the statsr central element and to
5 permit the central elements to be shorter than they would be if the nozzles
were not offset by 30, but were side by side. For example, if nozzles 29 and
50 (FIGURE 3) were both at the bottom, piping flanges at nozzle 29 could
interfere with flanges at nozzle 50. The directlon of rotation of the rotor
assembly is shown by arrow 62.
The complete fluid transfer paths may now be understood. For
example, in step 1 of the six-step cycle, raffinate tR) leaves the process
system by means of nozzle 32 (FIGURE 3~, having entered the valve by means
of the nozzle labeled 5B, (FIGURE 8, step 1), which is connected by a conduit
to the bottom of separation unit 59 and having passed through channel 61 to
15 nozzle 32. In step 2 of ~he process, R flows from separation zone 4 (FIGURE
1, step 2) and, therefore, enters the valve through the nozzle labeled 4B.
Since the rotor has indexed 60 from step 1 to step 2, nozzle 4B is aligned with
channel 61 and the raffinate flows through channel 61 to nozzle 32. In steps 3,
4, 5, and 6, raffinate flow is switched in a similar manner, as has been
2G discussed above. Between each end of channel 61 and the nozzles, raffinate
flows into annular spaces, one between the central elements and one between
end elements. The flow is con1:a;ned and prevented from intermixing with
other ~lows through the valve by the sealing means described above.
In a further example of fluid flow paths through the valve, IR from
25 the bottom of separation unit 6 ~FIGURE 1, step 1) enters the valve through
nozzle 27 (FIGURES 3, 6, 8) and flows to nozzle 26 via channel 37 (FIGURFS 3
and 4). From nozzle 26, it flows to nozzle 64 (FIGURE 3) via stator tie pipe
30, or tie conduit 30 (FIGURE 3). A tie pipe is used herein to mean a conduit
~2595~$
which connects and communicates between two nozzles of a valve. Impure
raffinate then flows from nozzle 64 to nozzle 65 (FIGURE 8, step 1) via a
channel (not shown) in the ri~ht rotor end element and the right portion of the
rotor central element. Nozzle 65 is connected to a conduit which routes the
5 stream to the top of separation zone 6. In step 2 of the cycle, the rotor
indexes so that impure raffinate from separation unit 5 flows ints channel 37.
It can be seen that nozzles of the first set communicate with third
set nozzles by means of channels in the first group, passages in the left hand
annular space between end elements, and passages in the central annular
space. Nozzles of the second set communicate with fourth set nozzles in a
similar manner~ the flow paths including channels in a second group of
channels.
Referring to FIGURE 1, it can be seen that a conduit containing
impure extract frorn the bottom Gf separation unit 1 must be connected with a
15 conduit feeding separation unit 2. This is accomplished by means of
passageway 66 in the rotor central element. Referring to FIGURE 8, step 1,
passageway 66 is located wholly within the rotor central element and connects
nozzles 67 and 68. Passageway 66 consists of three portions. A first end
portion is in register with no~zle 67, as can be seen in step 1 of FIGURE 8. A
20 second end portion cannot be seen in FIGURE 8, but is identical to the first
portion in configuration and i5 in register with nozzle 68. The third portion of
passageway 66 connects the first two portions and is perpendicular to them.
The third portion may be drilled from one face of the rotor central element
while the end element is disconnected from the central element and then the
25 first portion of the drllled hole, adjacent to the end of the central element,
can be plugged. Rotor seal elements 48 are used in the annular space and the
ends of passageway 66 in the same manner as in the ends of the channels. In
step 2 of the cycle, passageway 66 provides a flow path between nozzles 27
12~95~ t~
and ~9, and so forth for the other cycle steps. In the same manner,
passageway 70 provides a flow path between separation units 4 and 5 at step 1,
etc. Passageways 66 and 70 permit nozzles in the third set to communicate
with fourth set nozzles.
In this example, where the fluids flowing in the process are liquids,
pumps are required at certain locations. For example, referring to step 1 of
FIGURE 1, a pump is needed to transfer dilute extract from the bottom of unit
6 to the top of uni$ 6. This pump may be physically located in tie pipe 30. In
step 2 of the cycle, as can be seen from FIGURE 1, this same pump could be
used to transfer liquid between 5B and 5T. Alternatively, a single pump could
be associated with each column and used only when necessary to pump a
stream associated with that column. No further mention of apparatus such as
pumps and compressors used to transfer fluid need be made, as those familiar
with chemical processing are able to appreciate when such apparatus is
required and where in the process it needs to be located.
FIGURES 11 and 12 present an example in which a valve is used to
interconnect a plurality of conduits in two groups. The process depicted is
that of Broughton (U.S~ Patent 2,985,589). An explanation of the process is
presented above and supplemented in the following paragraphs. The
explanation of this example need not be as detailed as that of the previous
example, since the basic principles of the invention are known from the
previous example. This example is not intended to limit the scope of the
invention. There are twelve beds in vessel 71; one bed 72 is shown in the
cutaway portion of FIGURE 11. The bed 72 is retained by bed support means
at the bottom of the conical section. Liquid is distributed evenly over the top
of the bed by distributor 73, which may be a perforated plate. Liquid which
flows through the bed is collected in reservoir 74. Ii liquid is to be removed
from reservoir 74, it will flow out through an internal conduit 75 which
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communicates between the reservoir and a condui~ 106 external to vessel 71.
Conduit 106 carries liquid to the valve. If liquid is not to be removed, the flow
path is blocked in the valve and liquid overflows the reservoir and passes
through downcomer 77 to another distributor 73, to be distributed over the
5 next lower bed. If liquid is to be added, it flows in from the valve through
conduit 106 and is distributed over the next lower bed in the same manner as
liquid flowing through bed 72.
There are four basic streams whose connection points to vessel 71
and the beds therein are changed at each cycle step. They are labeled in the
10 same manner as the process of FIGURE l; F denotes feed, etc. Since there
are twelve beds, liquid flows to or from any given bed only every third cycle
step. For example, liquid flows in conduit 106 every third step and during the
other two steps, all liquid flows through downcomer 77. Consider that the
beds are numbered from Bl through ~12, starting at the top of vessel 71. Bed
15 72 is B6. Twelve cor,duits must then connect the vessel and the valve. These
are depicted by the twelve lines denoted 101 through 112 connected to the
larger central portion of the valve symbol, this larger portion of the symbol
representing a stator central element. Consider that at cycle step 1, feed (F)
flows to bed B6. Then raffinate (R) will flow from bed B9, desorbent (D) will
20 flow to bed B12, and extract (E) will flow from bed B3, all in step 1. During
step 2, F will flow to B7, R from B10, D to Bl and E from B4. The flows will
sequence in a similar manner through the balance of the twelve steps of the
cycle and then repeat.
The twelve conduits, 101 through 112, are connected to twelve
25 nozzles attached to the stator central element in the same configuration as
the earlier example presented herein. As in that example, five of the conduits
do not appear in the drawing of the whole valve (FIGURE 12~. The nozzles of
FIGURE 12 are labeled 101 through 106 and 112 to indicate the conduits
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~2~35~
connected to them, e.g., bed E~6 is served by conduit 106. There are three
significant differences between the embodiment used in this example and that
described above in connection with the Gerhold process (4,402,832) example.
There are no passageways such as 66 and 70, in the rotor central element. Tie
5 pipes are not required. The third difference is that the rotor assembly of this
embodiment rotates in 30 increments to accommodate the twelve cycle
steps. As in the Gerhold process example, there are four nozzles attached to
each rotor end element. Each of the four basic streams is routed to each end
elemen~. For example, feed (F) in conduit 120 (FIGURE 12) is supplied to each
end element by means of conduits 121 and 122, which ~ranch of f from conduit
120. At cycle step 1, F enters the valve through nozzle 124 and passes out of
the valve through nozzle la6. At cycle step 1, F entering the valve through
nozzle 123 flows no farther than the seal element in the annular space
between the rotor and stator central elements, because the central element
nozzle is not aligned with any of the four channels in the right rotor end
element. At cycle step 2, the rotor assembly having indexed through 30, F
flows into nozzle 123, through a channel in the right end rotor and right
portion of the rotor central element and out of the valve by means of nozzle
to which conduit 107 (FIGURE 11) is attached. Conduit 107 provldes the feed
stream to bed B7. During step 2, F which enters the valve through nozzle 124
is blocked in the same manner as in step 1, i.e., the channel end in the left
portion of the rotor central element is blocked by the stator central element
wall. The other basic flows, D, E and R, are routed in a similar manner. Note
that in this embodiment, the passageways shown in FIGURE 8 do not exist, so
there are always two nozzles on the left arld two on the right side of the
central element not in alignment with any channel, even when the other 4
nozzles are in alignment. Thus, during any one cycle step, none of the nozzles
on one of the two sides of the central element are in communication with a
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~59S~6
channel and only 4 of the 6 nozzles on the other side are in communication
with a channel, so that fluids are flowing in only 4 nozzles at any one time.
Means for sealing other than the seal rings described above may be
used. The annular space between end elements may be filled with
5 conventional shaft packing and compressed by means similar to seal ring
follower 15. Stationary lantern rings may be used in place of the rotating seal
rings to provide fluid flow passageways analogous to annular passage 44.
Another alternate to the above-mentioned seal rings is lip-type seals. These
might be used alone or in conjunction with rings spaced along the shaft to aid
10 in defining fluid passages, such rings being identical in configuration to a stack
of flat washers. In a similar manner, there are alternates to the use of rotor
seal elements 48, such as lip-type seals or a plastlc liner having self-
lubricating properties. A liner could be of tetrafluoroethylene, either rein-
forced or non-reinforced, having apertures in appropriate locations to allow
15 fluid to flow. Rigid retaining means might be provided at various points so
that any tendency of the liner to "creep" is minimized.
In each of the above examples, there have been four nozzles each
in the first and second sets of nozzles and six nozzles each in the third and
fourth sets. Of course, valves having different numbers of nozzles, to
20 accommodate more or fewer conduits~ can be designed. Varying numbers of
tie pipes can be used to connect nozzles of various groups, depending on the
flow pattern required in any particular process. It may be necessary to place
pipe expansion joints in the tie pipes, if tie pipes are used, to prevent damage
to the valve and/or leakage due to expansion caused by high temperature fluids
25 flowing through the valve. As discussed above, it may be desirable to utilize
flushing fluids; nozzles and channels can easily be provided for this purpose.
When a rotary valve is referred to as indexing"t is meant that the rotor
assembly is moving. A valve index position refers to one of the positions of a
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1~:59~
rotor assembly which is stationary and where openings are in register. The
components of the present invention may be fabricated from suitable
materials of cQnstruction, such as metals or plastics. Sizing of the flow
passages is easily accomplished by reference to any of the numerous standard
5 methods which are available.
To illustrate valve dimensions, a rotor assembly only for a valve
suitable for use in the Gerhold process discussed above with six separation uni ts
and moderate fluid flow rates requiring 1-1/2 inch (38.1mm) diameter channels
may have a total length of 42 inches (1.07m~, with a diameter of 5 inches (127mm)
at the end elements and 10 inches (254mm) at the central element; total valYe
length including driving mechanism may be about 7 ft (2.13m). A rotor end ele-
ment having four 4-inch (102mm) diameter channels to handle fluids at
moderate pressures may have a diameter of 14 inches (355.6mm).
In the examples presented, nozzles have been shown as short
15 lengths of conduit attached to, or located on, the stator assembly and having
flanges for connection to the conduits to be interconnected by the valve.
However, the term nozzle is used broadly to indicate means of communication
between conduits and annular volumes. For example, if it is desired to
connect conduits to a valve by means of welding, the term nozzle may refer to
20 openings in the walls of the stator assembly, the stator wall being configured
to accept welded-on conduits.
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