Note: Descriptions are shown in the official language in which they were submitted.
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,
Description:
"Lock for pressurized coal gasification plants"
The invention relates to a lock for withdrawing ash
from, or feeding coal into, a pressurized gas generator
of a coal-gasification plant, having a lock chamber and
a mechanism for opening and closing the lock chamber.
Such locks, which are known from use, make it possible,
despite the internal pressure, for the gas generator to
be opened in a controlled manner by the pressure in the
lock chamber being brought into line with the pressure
in the gas generator prior to ash being removed or coal
being fed.
Of course, such locks are subjected to high levels of
loading and, in particular, the sealing seats and
closure elements thereof have to withstand, over long
periods of time, both high temperatures and mechanical
and chemical wear.
In the case of the known locks, significant parts of
the opening/closing mechanism, in particular devices
for moving a closure element, are accommodated in the
lock chamber and elements for connecting these parts to
a drive are led out of the lock chamber.
The operation of fastening the aforementioned parts by
welding them in within the lock chamber requires a very
high production outlay, in particular the use of
complicated auxiliary devices and templates. Following
the stress-relief annealing essential for the lock
chamber, which forms a pressure vessel, the welded-in
components also have to be processed mechanically, e.g.
on a drilling machine.
It is also the case, disadvantageously, that the
internals decrease the useful volume of the lock
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chamber. Complicated, tightly welded-in internals, in
addition, make it more difficult for a corrosion-
prevention means to be provided in the lock chamber, or
prevent this altogether. The costs for maintaining the
internals are extremely high since, for this purpose,
in each case the entire lock has to be removed from the
plant and transferred into a special maintenance
workshop. In order for the parts which serve directly
for closure purposes to be maintained, it is necessary
for the entire opening/closing mechanism to be removed
in each case.
All of the internals of the known locks, furthermore,
are exposed to erosion, since they are located in the
flow region of the material which passes through the
lock.
It is an object of the invention to create a novel lock
of the type mentioned in the introduction which can be
produced with a lower level of outlay, and requires
less maintenance, than the known locks of this type.
The lock according to the invention for achieving this
object is characterized in that the opening/closing
mechanism comprises a subassembly in the manner of a
valve with a movable closure element, which can be
installed between the lock chamber and the gas
generator, and devices for moving the closure element.
It is advantageous according to the invention for the
significant parts of the opening/closing mechanism to
be concentrated in a separate subassembly which can be
installed as a complete unit, can be produced with
considerably reduced outlay and, for maintenance
purposes, can be conveniently removed as a whole. It is
no longer the case that any space is required for the
opening/closing mechanism in the lock chamber as such.
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The interior of the lock chamber can be kept entirely
free of parts of the opening/closing mechanism.
It is advantageous for the opening/closing mechanism of
the lock to have a further such subassembly as can be
installed at an outlet or inlet of the lock chamber,
said outlet or inlet being directed away from the gas
generator. Accordingly, the subassembly can be used on
the entry and exit sides both at the coal lock and at
the ash lock of a pressurized coal-gasification plant.
The subassembly expediently has a housing with a
respective flange on mutually opposite sides of the
housing for connecting to the gas generator and the
lock chamber.
The aforementioned closure element is preferably
designed in the manner of a plunger with a closure head
and a stem part.
In a particularly preferred embodiment of the
invention, the stem part has a sleeve which is open on
one side and can be moved on, and guided by, a bolt,
which projects axially into the sleeve. The sleeve
advantageously shields the guide bolt against the
oncoming material.
In an expedient design, the guide bolt projects from a
crosspiece, by means of which mutually opposite wall
portions of the housing are connected to one another.
It is expediently the case that the crosspiece, which
is located in the material stream, is thin, and
therefore it does not obstruct the material stream and,
itself, is not subjected to any high degree of wear.
In a further advantageous configuration of the
invention, the closure element is arranged coaxially in
relation to a cylindrical part of the housing. Such an
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arrangement, with given dimensions of the subassembly,
allows the greatest possible through-passage cross
section.
The aforementioned devices for moving the closure
element expediently have linkage elements extending
radially from the closure element.
In particular, these linkage elements project into
radial widened formations of the cylindrical part of
the housing, wherein those parts of the linkage
elements which are more remote from the closure element
are subjected to increasingly reduced levels of loading
by oncoming material and the effect of temperature.
In one embodiment, the linkage elements are pivot
levers which are articulated on the closure element
and, at their end which is directed away from the
closure element, are connected rigidly to a shaft which
is mounted on the housing and is led out of the
housing. Said shaft can be rotated via a crank element,
wherein the pivot levers, which are articulated on the
closure element preferably via a slot, move the closure
element axially.
In an alternative embodiment, the linkage elements are
rods which are connected rigidly to the closure element
and, at their other end, are connected rigidly to a
pull/push rod which can be moved parallel to the
closure element and is led out of the housing.
Both the aforementioned shafts and the pull/push rods
are arranged far outward in the radial direction, where
there is sufficient installation space available for
driving means.
It is expediently the case that the housing is
connected, on the outside, to at least one power
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cylinder, which moves the shafts via a respective crank
element or the pull/push rods.
It is preferably the case that the parts which are
exposed to the material stream have a roof-shaped cross
section with a roof peak directed counter to the
material stream.
Accordingly, in one aspect the present invention
resides in a lock for withdrawing ash from, or feeding
coal into, a pressurized gas generator of a coal-
gasification plant, having a lock chamber and an
opening and closing mechanism which is intended for
opening and closing the lock chamber, and comprises a
first subassembly with a closure element in the manner
of a valve, said subassembly being intended for
installation between the lock chamber and the gas
generator, and devices for moving the closure element,
wherein the closure element is designed in the manner
of a stamper with a closure head and a stem part,
wherein the stem part comprises a sleeve which is open
at only one end and is guided on a bolt, which projects
axially into the sleeve, the sleeve shielding the bolt
against oncoming material.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail
hereinbelow with reference to exemplary embodiments and
the accompanying drawings, which relate to said
exemplary embodiments and in which:
figure 1 shows partial views in section (a) and (b) of
a first exemplary embodiment for a lock
according to the invention,
figure 2 shows a cross-sectional view of a valve-like
subassembly of the lock from figure 1,
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figure 3 shows a side view of a valve-like subassembly
with two hydraulic cylinders,
figure 4 shows partial views in section (a) and (b) of
a further exemplary embodiment for a lock
according to the invention,
figure 5 shows a cross-sectional view of a valve-like
subassembly of the lock from figure 4,
figure 6 shows a detail of the lock from figure 4, and
figure 7 shows a schematic illustration of a
pressurized coal-gasification plant with
valve-like subassemblies according to the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A pressurized coal-gasification plant, which is
illustrated as a basic diagram in figure 7, comprises a
pressurized gas generator 1, to which coal can be fed
from above via a lock 2'. A further lock 2 for
withdrawing ash is located on the underside of the gas
generator. Each of the locks 2, 2' comprises a
respective lock chamber 3, 3'. A respective subassembly
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4, 4', 4", 4', which operates like a valve and will be
described hereinbelow with reference to figures 1 to 6,
is located between the lock chambers 3, 3' and the gas
generator 1 and also at the entry to the lock 2' and
the exit from the lock 2.
Figure 1 shows exemplary embodiments for the valve-like
subassembly 4 between the gas generator 1 and the lock
chamber 3 and an exemplary embodiment for a valve-like
subassembly 4' at the lower end of the lock chamber 3,
said subassembly 4' corresponding essentially to the
subassembly 4.
The two subassemblies 4, 4' each have a housing 5 with
a round-cylindrical housing part 6 and radial widened
formations 7 and 8. The subassembly 4 is screw-
connected to the gas generator 1 and the lock chamber 3
via flanges 9 and 10 on the round-cylindrical part 6 of
the housing 5. In the case of the subassembly 4', there
is a screw-connection between the corresponding flange
9 and the lock chamber 3. The housing 5 has a
respective inspection opening 11.
A plunger-like closure element 12 with an upwardly
conical closure head 14 is arranged coaxially in
relation to the cylindrical part 6 of the housing 5
and, in the position which is shown in figure 1, rests
on a closure seat 13, with the gas generator 1 being
sealed in the process. The closure head 14 is connected
to a push rod which is coaxial in relation to the
cylinder axis of the cylindrical part 6 of the housing
5, merges into a sleeve 15 and, together with the
sleeve, forms the stem part of the plunger-like closure
element 12. The sleeve 15, which is open in the
downward direction, can be moved axially on a bolt 16
and is correspondingly guided by the bolt 16. The bolt
16 is connected rigidly to a crosspiece 17, by means of
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which mutually opposite wall portions of the housing 5
are connected to one another.
Pivot levers 18 and 18' each have one end articulated,
via slots, on extension arms of the sleeve 15 and, at
their other end, are connected rigidly to a respective
shaft 20, 20'. The shafts 20, 20', as can be seen in
particular in figure 2, can be rotated in bearing means
19 and 19', which are connected to the housing 5 on two
wall portions of the widened formation 7, 8, said wall
portions being spaced apart opposite one another.
As can also be seen in figure 2, the shafts 20, 20' are
each connected rigidly to a respective connecting rod,
21, 21'. A hydraulic cylinder 22, which is articulated
on the free ends of the connecting rods 21, 21', can be
used to rotate the shafts 20, 21 and thus rotate the
pivot arms 18, 18', with the closure element 12 being
displaced in the process.
As can be gathered from figure 3, instead of a
hydraulic cylinder 22, it is also possible to use two
separate cylinders 23 and 23', each rotating the
respective shaft 20, 20'.
It can also be seen from figure 1 that the closure seat
13 is formed by an annular element 30 which is secured
between the gas generator 1 or the lock chamber 3 and
the housing 5 of the subassembly 4 or 4', said housing
being connected to the gas generator or the lock
chamber in each case. The annular element 30 comprises
a plurality of individual rings, which are produced
from different materials and meet the requirements
relating to strength, temperature resistance and
sealing.
In order to withdraw ash from the gas generator 1, with
the aid of the hydraulic cylinder 22 or of the two
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cylinders 23, 23', the shafts 20, 20' of the
subassembly 4 are rotated, and therefore the pivot
levers 18, 18' pivot into the position indicated by
dashed lines. The pivot levers here move the closure
element 12 axially, as a result of which the closure
head 14 lifts up from the closure seat 13 and is
displaced into the position indicated by dashed lines.
Ash can then pass, through the freed passage, from the
gas generator 1, through the cylindrical part 6 of the
housing 5, into the lock chamber 3, of which the
internal pressure has previously been brought into line
with the pressure prevailing in the gas generator 1.
The upwardly conical shape of the closure head 14
promotes the flow of ash, as do the bevels of the
annular element 30 which are formed above the closure
seat 13. The widened formations 7, 8 each have a
sloping base, and therefore ash exiting laterally at
the passage passes of its own accord back into the main
stream. The sleeve 15 covers large parts of the bolt 16
in relation to the stream of ash, and therefore the
bolt 16, as the part which guides the closure element
12, is not subjected to any high level of wear.
The rotatable shafts 20, 20' seal the housing in the
outward direction. During rotation, no ash passes into
the region between the bearing means 19, 19' and the
respective shaft 20, 20'.
In order to empty the lock chamber 3, with the
connection between the gas generator 1 and the lock
chamber 3 closed by way of the subassembly 4, and with
external pressure prevailing in the chamber 3, an
opening is established at the lower end of the lock
chamber 3 with the aid of the subassembly 4' and all
the ash is let out of the lock chamber.
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In the case of maintenance, the subassemblies 4, 4' are
each removed as a whole unit and possibly changed over
for a subassembly which has already been serviced.
In the case of the exemplary embodiment shown in
figures 4 to 6, like or like-acting parts have the same
designations as in the preceding exemplary embodiment,
the letter a having been added to the relevant
designation.
The exemplary embodiment according to figures 4 to 6
differs from the exemplary embodiment described above
in that, rather than pivot levers being articulated on
a sleeve 15a of a closure element 12, the sleeve 15a is
connected rigidly to a pull/push rod 25, 25' via a
respective connecting rod 24, 24'. The pull/push rod
25, 25' can be moved parallel to the longitudinal axis
of the sleeve 15a in a respective bearing means 26, 26'
connected to a housing 5a.
As can be seen in figures 5 and 6, the pull/push rods
25, 25' are moved in each case with the aid of two
hydraulic cylinders 27, 28, which act on a transverse
rod 29, which crosses the pull/push rod 25, 25'.
