Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates -to a ~ust trap and valve system
therefor, and more specifica]ly to an improved dust valve which
will permit inspection, cleaniny and/or replacernent of wearing
surfaces without disconnnecting or removing the entire trap unit,
and which will exhibit improved seating characteristics and wear
resistance to abrasive materials.
In United States Patents No. 3,257,045 and the improve-
ment thereon No. 3,410,422, assigned to the assignee of this
invention, there was described a dust trap and valve assembly
which would permit inspection, cleaning, and replacement of worn
parts without dismantling the entire assembly. Prior to that
invention, dust traps and valves therefor were provided as an
integral unit. When it was necessary to replace worn parts, it
was necessary to either replace the entire trap unit or at least
remove the trap unit from its vacuum line for disassembly. The
improvement described in the above-identified patents utilized a
valve seat and flapper disposed adjacent an access door. By
removing the access door from the trap unit the flapper and seat
could be visually inspected, cleaned, or removed and replaced.
The device of the instant invention is yet another improvement
utilizing a circular valve seat and frusto conical flapper for
improved seating characteristics and a deflector means for re-
ducing wear on the valve flapper as abrasive materials pass
through the trap housing.
Basically, dust traps are well known and are used in
dust collection systems wherein the dust particles are abrasive,
highly abrasive, or in some instances non-abrasive. Dust col-
lection systems are maintained under vacuum and the traps are
utilized to permit the free dumping of dust collec-ted in the
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systems without exposing the vacuum in the vacuum line to the
atmosphere. A dust trap utilizes normally a pair of dust valves
installed in a housing which are operated by cycling the opening
and closing of the valves so that dust enters a first chamber
from the vacuum line, communication between that chamber and
the vacuum line is closed, and dust then enters a second chamber
by gravity and exists the trap. Communication between the second
and first chamber is then closed and communication between the
first chamber and vacuum line is subsequently opened to repeat
the process. Dust valves are important in iron or sintering
plants, pelletizing plants and a wide variety of other operations
well known in the art. Valves have also been utilized in the
manufacture of non-abrasive materials such as talc. The instant
invention, however, is primarily intended for use with abrasive
materials as noted above.
In the above-identified patents, the flapper described
is a rectangular plate which engages a seat at an acute angle
to the vertical. The seat consists of a long side and a short
side, and the valve includes a drive means for closing and opening
the valve by moving the flapper into and out of engagement with
the seat. The seat then describes a rectangle in cross-section
having leading edges which engage the peripheral upper surface
of the flapper to close the valve. The drive means is intended
~ to provide a snap action to quickly close the valve. However,
the metal-to-metal interface between the flapper and seat is
subject to wear as abrasive particles pass through the valve.
Obviously, as the interface surfaces wear, they will reach a
point when the valve will no longer be capable of sealing the
vacuum line from the atmosphere. At this point the worn surfaces
must either be replaced or reground and therefore the dust trap
and valves described in the above patents had the capability of
rapid inspection, removal, and replacement of these surfaces
through an access door, thereby minimizing down tlme for the
unit.
It has been discovered, however, that an improved dust
valve can be provided utilizing a frustro conical flapper which
engages a corresponding valve seat at an angle substantially per-
pendicular to the vertical. The angled frustro conical surfaces
then engage the interior surfaces of the seat to provide improved
sealing capability against wear from abrasive dust particles. In
addition, the device of this invention further ~educes wear when
dust passes through the valve by providing a deflection means
whereby the dust particles will not normally impinge upon the
upper surface of the open, frustro conical flapper. The flapper
opens the valve by moving to a position substantially parallel
to the vertical. A deflector and wear plate are also provided
in the valve seat and adjacent the access door whereby the dust
particles will be deflected away from the open flapper sealing
surface when passing through the valve.
As is described in the above-referenced patents and as
is well known in the prior art, a variety of different means can
be provided for opening and closing the valve flappers. Pneu-
matic or hydraulic means with conventional controls can be utilized
and are preferred. A motor means could also be utilized, and a
mechanical spring or counter balancing weight could also be uti-
lized. The embodiment of this invention described hereinafter
is not intended to be limited to the particular means utilized to
open and close the valves in sequence.
Accordingly, it is an object of this invention -to provide
an improved dust trap and valves therefor which will be wear
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resistant to a greater degree with abrasive materials.
The invention provides a dust valve body having a flow
path therethrough from one end to the other; a conduit member
removably mounted in said valve body and forming a valve seat,
the flow path through said conduit member being substantially
coaxial with the flow path through said valve body; said conduit
member being substantially cylindrical and forming said valve
seat on a radial internal edge thereof; a valve actuator shaft
passing through said valve body adjacent a side of said valve
body and means for rotating said shaft; a frusto conical valve
flap and self aligning means carried thereby for engaging said
flap at its frustro conical surface with the radial edge of
said seat, said flap removably coupled to said valve actuator
s`naft for moving into and out of engagement with said valve
seat whereby a seal will be maintained between the frustro
conical surface of said flap and the radial edge of said seat;
means for deflecting the flow through said conduit and said
valve body so that when said flap is fully rotated out of en-
gagement with said valve seat said flow will not impinge upon the
surface thereof; and access means carried by said valve body for
providing access to the interior of said body for removal of said
conduit member and said valve flap from inside said valve body;
said conduit member being disposed adjacent the upper portion
of said valve body and said valve seat is disposed substantially
perpendicular to the vertical longitudinal axis of said valve
body; said means for deflecting the flow includes a semicircular
flange disposed within said conduit member opposite said valve
seat to deflect the flow towards a further deflecting means
comprising a wear plate; said wear plate disposed adjacent the
side of said valve body opposite the valve actuator shaft.
These and other features will become readily apparent
with reference to the drawings and following description wherein:
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FIGURE 1 is a perspective view of the dust valve unit
of this invention having an access door removed exposing the
back of a wear plate therein;
FIGURE 2 is a vertical cross-section through one of
the valve units of this invention showing the open flapper in
phantom;
FIGURE 3 is a cross-sectional view taken along line
3-3 of Figure 2;
FIGURE 4 is a top plan view of the valve seat of the
valve of this invention exposing the deflector surface; and
FIGURE 5 is a fragmentary cross-sectional view illust-
rating the flapper engaging the seat with one of the four
alignment lugs shown.
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With attention to the drawings and to ~igure 1 in parti-
cular, the dust trap 10 of this invention consis-ts of identical
dust valves 12 and 14 which are bolted together at lower and
upper mounting flanges 16 and 18. The upper mounting flange
20 of upper valve 12 is mounted on a vacuum line (not shown) in
the conventional fashion. An external drive means 22 is provided
to open and close the valve, as will be subsequently described.
Drive means 22 is shown as a piston and cylinder with an external
controller (not shown). ~Iowever, as noted above, any conventional
drive means can be utilized, and this invention is not intended
to be limited to pneumatic,hydraulic, or other conventional types
of drive means.
An access plate 24 normally covers an access opening 26.
A wear plate 28 is provided within the valve at the access open-
ing, and is preferably mounted by a bolt 30 to the plate 24.
Accordingly, in order to inspect the interior of the valve, the
access plate 24 is unbolted from the housing 32 of either valve
12 or 14 as shown in Figure 1, and the nut 34 removed from bolt
30. The access door 24 may then be removed from the valve,
exposing wear plate 28, which may also be removed to provide ac-
cess to the interior of the valve. This type of access opening
as in the above-referenced prior patents, permits inspection,
cleaning, and replacement of parts within the valve, without
` actually removing flange 20 from the vacuum line (not shown).
The drive means 22 as shown includes a connecting ~od 38
which in turn is attached to a lever arm 40. Lever arm 40 is
affixed to an end of shaft 42 which in turn mounts the valve
flapper as will be subsequently described. Accordingly, vertical
movement of connecting rod 38 will be translated through lever
arm 40 to rotational movement of shaft 42. Se~uential opening
and closing of the valves in ~rap 10 is achieved by drive means
22, causing -the shafts 42 to rotate in the desired direction.
Any conventional controller (not shown) may be utilized for
operation of the trap as will be subsequently explained.
~ith attention to Figures 2-5, there is shown, for the
purposes of illustration, a single valve member either valve 12
or 14. The valve includes a housing 32 and in the case of valve
12, lower mounting flange 16 and an upper mounting flange 20 for
attachment to a vacuum line (not shown).
The valve itself consists of a valve seat 46 and a flapper
48. Seat 46 is bolted to flange 20 as shown in Figure 2 and is
removable by removing the bolts from within the housing 32. Access
' ` ~ to the bolts 50 then is through the access opening 26. Valve seat
46 includes an interior/b ~Q~c~n}ti-ff~ 52 which is intended to
receive and mate with the flapper 48 to provide a seal. The bottom
inside edge of the seat is ground radially so that the flapper comes
up against a radius on the inside of the seat. Seat 46 further
includes a semicircular deflector 54 which in conjunction with wear
plate 28 facilitates passage of the dust particles vertically
through the interior of housing 32 from the inlet port 56 through
an outlet port 58 when flapper 48 is disposed in the position
shown in phantom in Figures 2 and 3.
Flapper 48 is preferably mounted by a clevis and pin assem-
bly 60 to a lever arm 62 which in turn is affixed rigidly to shaft
42. Accordingly, downward movement of connecting rod 42 and lever
arm 40 will cause the flapper to rotate from the closed position
shown in Figures 2 and 3 to the open position shown in phantom
in Figures 2 and 3. The flapper of this invention then rotates
approximately 90 from a closed position disposed perpendicular to
the vertical access of the device to an open position disposed
substantially parallel to the vertical access of the device. Dust
particles entering inlet 56 then are deflected by deflector 54
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onto wear plate 28 which has a wear surface 64 which is semi-
circular in configuration and ultimately through outlet port 58.
In this way, the particles do not impinge upon flapper 48 as they
pass through the device. The flapper 48 then will not be subject
to the extreme wear which could occur if abrasive dus-t particles
passing through the valve impinged on its surface. Flapper 48
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,7~ ~ for sealing purposes is frustro conical in configuration providing
'` - an inclined surface 66 which mates with ~ e 52 of
valve seat 46. In addition, four centering lugs 68 are provided
which also guide the flapper into the seat when connecting rod
38 moves upwardly. As noted in our prior patents, it is desirable
to close the valve with a "snapping" action for sealing purposes.
In order to remove the flapper for grinding or replace-
ment, the pin 70 in clevis 60 may be removable, or in the alterna-
tive, if desired, lever arm 66 may be removable from shaft 42 byany conventional fastening means (not shown). As will be obvious
to those skilled in the art, the interior of housing 32 is intended
to be sealed. Therefore, shaft 42 will extend through housing 32
and appropriate bearings for sealing purposes will be provided
as shown in general at 72 in Figure 3. In addition, appropriate
gaskets may be required at the flanges 16, 18, or 20, and at the
access door 24.
OPERATION
The trap 10 of this invention functions similarly to that
described in our above-identified patents. For example, the
flapper in upper valve 12 may be opened and the flapper in lower
valve 14 closed to seal the vacuum line (not shown) from the
atmosphere. Dust particles from within the line accumulate within
the upper valve 12 against the closed flapper 48 of lower valve 14
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for a predetermined period of tirne. Then the upper drive means
22 will close the upper valve 12 by rotating the flapper 4~
against seat ~6. Lower valve 14 is then opened by rotating the
flapper 48 from the position shown in Figures 2 and 3 to the
position shown in phantom in Figures 2 and 3. The dust particles
collected then fall through the device. After the lower valve
is empty lower valve 14 is empty, the valve is closed by roating
flapper 48 against seat 46 and the upper valve is opened by ro-
tating flapper 48 away from seat 46 to repeat the process. The
operation may be manual, or preferably controlled, as desired.
In summary then, by providing a frustro conical valve
flapper in combination with the deflector and wear plate, a
circular valve is provided which will exhibit greatly improved
wear characteristics. In addition, the frustro conical flapper
is received within the seat and automatically aligned therewith
to provide better sealing capability. The device of this inven-
tion, then, has been found to be preferable to prior devices
relative to abrasive particles and requires greatly reduced down-
time for maintenance or replacement of the parts therein. When
it is necessary, however, to replace or grind a wear surface,
all of such surfaces may be removed from within the valve at the
access opening without disassembling the entire trap and parts
can be similarly replaced through the opening. Therefore, even
when it is necessary to replace parts, the replacement may be
rapidly and efficiently achieved.
The invention may be embodied in other specific forms
without departing from the splrit or essential characteristics
thereof. The present embodiment is, therefore, to be considered
in all respects as illustrative and not restrictive, the scope of
the invention being indicated by the appended claims and all
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changes which come within the meaning and range of equivalency
of the claims are, therefore, intended to be embraced therein.
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