Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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POST MOUNTING ASSEMBLY AND METHOD FOR MOLTEN METAL PUMP
CROSS REFERENCES TO RELATED APPLICATIONS: U.S. Provisional Application
for Patent No. 62/270,357, filed 12/21/2015, with title "Post Mounting
Assembly and
Method for Molten Metal Pump" which is hereby incorporated by reference.
Applicant
claims priority pursuant to 35 U.S.C. Par. 119(e)(i).
Statement as to rights to inventions made under Federally sponsored research
and
development: Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The invention relates to pumping molten metal and more particularly to molten
metal
pump apparatus and methods for assembling and disassembling such apparatus.
2. Brief Description of Prior Art.
A molten metal pump apparatus generally includes a motor mounted above a
molten
metal bath. The motor drives a rotatable impeller pump having one or more
impellers
submerged in the bath. In operation, the rotating impellers draw molten
material from
the bath and pump it through a conduit routed to a subsequent station for
further
processing.
The molten metal pump typically includes a base having inlet and outlet
passages for
intake and discharge of the molten metal being pumped. The pump base together
with
the impeller are submerged in the molten metal, supported on the bottom of the
vessel
containing the molten metal. The pump base is typically connected by
refractory
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cement and/or mechanical arrangements to a plurality of vertically extending
support
posts which are also connected to a drive arrangement positioned above the
level
molten metal. In typical installations, these vertically extending posts may
be several
feet long, e.g. one to four feet in length or longer, in order to provide
adequate
clearance between the molten metal level.
The portions of the pump assembly submerged in the molten metal are directly
contacted and exposed to the harsh conditions thereof, and are formed of
refractory
material such as graphite, silicone carbide, alumina, zirconia or hexalloy.
The posts
extend through a level of the molten metal and are connected to a motor
mounting plate
of the drive arrangement positioned above the level molten metal.
In prior art arrangements, downwardly opening post sockets are fixed to the
motor
mounting plate and receive the upper ends of the posts. One or more post
sockets may
be fixed to a post support plate, as by welding, and the support plate is
secured to the
motor mounting plate. In prior art arrangements, the posts may also be secured
within
the post's sockets by means of a refractory cement, bolts or other clamping
devices.
Despite the positive properties for this described application, graphite and
ceramics still
corrode and deteriorate over time. The vertical posts that extend through a
level of
molten metal begin to erode as a result of use and molten metal pumps must be
more
frequently maintained and replaced than other types of pumps. The replacement
or
servicing of a pump having operating components submersed in molten metal is a
time
consuming exercise. First, the pump must be removed from the molten metal
which
generally causes down time. Then the pump along with the molten metal
contained
thereon must be allowed to sufficiently cool to allow it to be disassembled.
Once the
deteriorated components are sufficiently cooled, the vertical posts that have
sufficiently
deteriorated are replaced, and the molten metal buildup on the various pump
surfaces
must be sufficiently removed to allow disassembly and/or re-use of the pump
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components. Then the pump must be reassembled with the combination of old
components or parts, along with the replacement parts.
As previously described, there are certain components of the pump which are
typically
cemented together in order to achieve a balanced and sufficiently rigid pump
structure
to allow continuous operation of the pump. However, when the pump must be
disassembled, the cemented joints can be very difficult to disassemble.
In the case of the vertical posts between the pump base and the motor mount
structure,
the posts have traditionally been cemented into bored holes within the base.
In the
case of the base for example, when the pump is disassembled, the cemented
portion of
the posts must normally then be chipped, dug or drilled out in order to allow
a new post
to be placed in the same bore. This makes the disassembly much more difficult.
A
most significant disadvantage to prior art arrangements is therefore the need
to cleanly
remove the post when it is necessary to replace the post.
Further, during assembly of the pump, it is important that the pump components
be
accurately aligned in order for the pump system to work efficiently once it is
back in the
molten metal. The combination of the components are very heavy, and once the
posts
for example are cemented in place as described above, it is then very
difficult if not
impossible to align if necessary.
As will be seen from the subsequent description, the preferred embodiments of
the
present invention overcome shortcomings of the prior art.
SUMMARY OF THE INVENTION
A post mounting assembly for assembling and disassembling a molten metal pump.
The post mounting assembly includes a pump base, at least two (2) support
members
or posts, and post sockets. Each post may include a protective sleeve that
surrounds
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the post's mid-section. The post socket having a first half and a second half
that when
joined defines a body portion for receiving an upper end of the post.
The assembly of the posts to the mounting base illustrates an embodiment of a
cement-
less pump joint which is an objective of the present invention. Further, the
assembly of
the post to the post socket illustrates an embodiment of a cement-less pump
joint which
is a further object of the present invention. As a result, a replacement post
identical to
posts of the present invention may be provided without the need to dig out a
cement
joint but instead can be more easily removed and replaced.
The base of the present invention includes at least two (2) mounting bores
therethrough
for receiving the lower end of the post. Each mounting bore includes at least
one tab
disposed substantially adjacent the upper surface of the base member. The at
least
one tab includes flat surfaces that align with flat surfaces disposed on the
lower end of
the posts such that the lower end of the posts can be inserted in the mounting
bores
and rotating the posts within the mounting bores effectively secures the posts
to the
base member.
The upper end of the posts are shaped and sized to be received within the post
socket.
The post socket and the upper end of the posts include apertures for alignment
and for
receipt of a pin member that secures the upper end of the post to the post
socket. The
coupling configuration between the upper end of the post and the post socket
provides
very tight tolerances such that the joint connection as described does not
require
equipment to align the pump during assembly and installation.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a top perspective view of a pump base for a molten metal pump.
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Fig. 2 illustrates one of the bored holes within the pump base for mounting a
vertical
post.
Fig. 3 illustrates a vertically extending post with a portion of the
protective sleeve
removed for illustration.
Fig. 4 illustrates an upper end of the post of Fig. 3.
Fig. 5 illustrates a lower end of the post of Fig. 3.
Fig. 6 is a top perspective view of a post socket.
Fig. 7 is an alternate embodiment of the vertically extending post with a
portion of the
protective sleeve removed for illustration.
Fig. 8 is a second alternate embodiment of the vertically extending post with
a portion of
the protective sleeve removed for illustration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with the present invention, a post mounting assembly and method
for
molten metal pump is disclosed. The post mounting assembly is directed to a
molten
metal pump apparatus and method for assembling and disassembling such
apparatus.
Specifically, it will be noted in the drawings that the post mounting assembly
provides a
pump assembly which does not require as many or any cemented joints as does
prior
art pumps. Further, the present invention provides a pump and assembly system
which
tends to self-align the pump during the assembly process thereby reducing or
eliminating the need for alignment apparatuses. In the broadest context, the
post
mounting assembly for molten metal pump consists of components configured and
correlated with respect to each other so as to attain the desired objective.
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Figs. 1 ¨ 6 illustrate a preferred embodiment of a post mounting assembly made
in
accordance with the present invention. The assembly of the present invention
includes
a pump base 10 (shown in Fig. 1), at least two (2) support members or posts 20
(shown
in Figs. 3 ¨ 5), and a post socket assembly 30 shown in (Fig. 6).
A molten metal pump (not shown) generally includes a base having an impeller
mounted therein. The impeller is secured to a driveshaft mounted for rotation
within the
base. The upper end of the driveshaft is connected to a motor.
The pump further includes at least two (2) identical vertical support members
that are
spaced apart to provide stability. Each of the vertical support members
include an end
for connection to a motor mounting plate. Each of the support members further
include
an end for connection to the base.
Referring to Fig. 3, the at least two (2) support members or posts illustrated
as numeral
20 for the present invention include an upper end 22 for connection to the
motor
mounting plate, and a lower end 24 for connection to the base member 10. Each
upper
end 22 of the posts 20 are connected to the motor mounting plate using the
post socket
30. The post socket assembly 30 is described below in greater detail.
Referring to Figs. 1 ¨ 2, the base member 10 includes at least two (2)
mounting bores
12 therethrough for receiving the lower end 24 of the post 20. As stated, the
mounting
bores 12 define a void completely through the base member 10. As shown, the
mounting bores 12 have a substantially circular configuration and each
mounting bore
12 includes at least one tab member 14 that is vertical the upper surface 10A
of the
base member 10. As illustrated, a top edge 14A of each tab member 14 is
substantially
adjacent the upper surface 10A. Each tab member 14 further defines a flat
surface 15
within the mounting bore 12 (best shown in Fig. 2), and a lower edge 16.
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As shown in Fig. 2, each of the mounting bores 12 include a first distance
designated as
"Dl" which is the diameter of the bore 12 with the at least one tab member 14,
and a
second distance designated as "D2" (shown in Fig. 1) which is the diameter of
the bore
12 below the lower edge 16 of the at least one tab member 14. The first
distance D1 is
less than the second distance D2 of the mounting bore 12.
Fig. 5 best shows the lower end 24 of the posts 20. The lower end 24 sized and
shaped
to be received within the mounting bore 12 of the base 10. More particularly,
the lower
end 24, like the mounting bore 12 includes at least one flat surface 25 and a
surface 28
adjacent each of the at least one flat surface 25.
In application, aligning the at least one flat surface 25 of the post's lower
end 24 with the
flat surface 15 of the mounting bore 12 enables the lower end 24 of the posts
20 to be
inserted in the mounting bore 12 until the upper surface 10A is in contact
with a stop 27
of the lower end 24. Further, once the stop 27 is in contact with the upper
surface 10A
as described, the post's lower end 24 will be disposed within the mounting
bore 12 and
below the lower edge 16 of the at least one tab member 14 such that a ledge 29
of the
lower end 24 is in abutting communications with the lower edge 16. As
illustrated, the
ledge 29 is adjacent the surfaces 25, 28. In this position, the post 20 can
rotate within
the bore 12.
Once the lower end 24 is inserted in the mounting bore 12 as described,
rotating the
post 20 within the mounting bore 12 effectively secures the post 20 to the
base member
10.
As should be understood, further rotating the post 20 within the mounting bore
12 until
the surfaces 15 and 25 are aligned releases the post 20 from the mounting bore
12.
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The assembly of the lower end 24 of the posts 20 to the mounting base 10 as
described
illustrates an embodiment of a cement-less pump joint which is an objective of
the
present invention. Therefore a replacement post identical to post 20 may be
provided
without the need to dig out a cement joint but instead can be more easily
removed and
replaced.
Referring to Fig. 6, a post socket assembly 30 generally includes an upper
plate 31 and
a body portion 32. In application, the upper plate 31 is secured to the pump's
motor
mounting plate (not shown) in any convenient manner, such as, threaded
fasteners.
The body portion 32 having an opening 33 to access an interior 34. The opening
33
and interior 34 are sized for receipt of the upper end 22 of the post 20.
As will be further described, the upper end 22 of the post 20 is secured
within the
interior 34 of the body portion 32 with a pin member (not shown) known in the
art that in
application, is inserted through a post aperture 26 (see Fig. 4) that extends
through the
upper end 22 of the post and a socket aperture 36 that extends through the
body
portion 32 of the socket 30. More particularly, the pin member secures the
upper end
22 of the post 20 to the post socket 30. The pin member is inserted through
the aligned
apertures 26, 36 when the upper end 22 of the post is positioned within the
interior 34 of
the body portion 32 of the post socket 30. A retainer (not shown) known in the
art
secures the pin member within the apertures 26, 36.
After the upper end 22 of the post 20 is received in the interior 34 of the
body portion
32, and the apertures 26, 36 aligned as described, the pin member is inserted
through
the apertures 26, 36 and retained. The pin member is dimensioned such that it
fits
snugly but slidingly in the passageway defined by the apertures 26, 36 having
the
substantially same diameter, and is of a length such that it extends through
the body
portion 32.
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Accurate positioning of the vertical posts 20 is permitted prior to inserting
the pin
member. Thus, the pin member when filled through the apertures 26, 36, will
set the
posts 20 at a precise position. The result is a precise positioning of the
posts and
results in precise axial position of the pump's components.
As illustrated, the assembly 30 including the upper plate 31 and body portion
32 are
defined by a first half 37 (as illustrated first half 37 includes half 32A of
the body portion
32 and half 31A of the upper plate 31) and a second half 38 (as illustrated
second half
38 includes half 32B of the body portion 32 and half 31B of the upper plate
31). In
application, the assembly 30 can be separated or opened (not shown) for
inserting or
removing the upper end 22 of the posts 20, or in the closed position as shown
in Fig. 6
for retaining the upper end 22 of the posts 20 as described.
In application, the upper plate of the first half 37 is appropriately attached
to the pump's
motor mounting plate with bolts (not shown) for example through apertures 39A.
The
upper end of the post is then positioned with the interior 34 of the body
portion of the
first half. The pin member can then be partially inserted through the socket
aperture in
the first half 37 and partially through the aperture 26 of the post. The
second half 38 of
the body portion is now positioned with the upper end of the post such that
the pin
member can pass through the socket aperture of the second half 38 and
retained. The
upper plate of the second half 38 can then be appropriately attached to the
pump's
motor mounting plate with bolts (not shown) for example through apertures 39B.
As should be understood, once the first and second halves 37,38 are positioned
as
described with upper end 22 retained with pin member as disclosed, and the
halves
37,38 are attached to the motor mounting plate as described, the halves 37, 38
are
effectively joined with one another with the upper end 22 properly aligned and
affixed
therein.
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The assembly of the upper end 22 of the post 20 to the post socket 30 as
described
illustrates an embodiment of a cement-less pump joint which is an objective of
the
present invention. Therefore a replacement post identical to posts 20 may be
provided
without the need to dig out a cement joint but instead can be more easily
removed and
replaced.
This coupling configuration between the upper end 22 of the posts 20 and the
post
socket 30 provides very tight tolerances such that the joint connection as
described
does not require other jigs or equipment in order to align the pump during
assembly and
installation.
It should be appreciated that according to the post mounting assembly and
method as
described, the posts 20 can be mounted to the base member 10 and the post
socket 30
without requiring cement. As a result, disassembling the pump becomes much
less
difficult. Further, the present invention provides a pump and assembly system
which
tends to self-align the pump during the assembly process.
As shown in Fig. 3, the post 20 may further include a first groove 21A and a
second
groove 21B that each horizontally extend around a mid-section designated as
"MS" of
the posts 20, with the first groove 21A being just below an upper point P1 of
the mid-
section MS, and the second groove 21B being just above point P2 of the mid-
section
MS. It should be understood that the mid-section MS of the posts 20 represents
an area
on the posts that commonly corrodes and breaks due to use.
The posts 20 may further include a protective sleeve 23 or wrap for holding
and
protecting the mid-section MS of the posts 20. More particularly, the sleeve
is a
protective sleeve that is configured for providing protection, e.g., to slow
down the
corrosion and erosion process that naturally occurs due to extending
submersion in the
molten metal.
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In the preferred embodiment, the protective sleeve 23 is in surrounding
relationship to
the mid-section MS of the posts 20 as shown, e.g., substantially from point P1
approximately above the first groove 21A towards a point P2 approximately
below the
second groove 21B. The sleeve 23 may extend a slightly greater or lesser
distance than
the illustrated and described distance from P1 to P2.
The purpose of the sleeve 23 is to separate the molten metal from the mid-
section MS
of the posts 20 during application. By limiting or lessening the extent of
communication
between the molten metal and the mid-section of the posts 20, the Applicant
has found
the extent and speed of corrosion is minimized during use.
During manufacture, a fill composition (not shown) for the protective sleeve
23 is poured
into a mold between the sides of the mold and the mid-section MS of each post
20. The
fill composition intersperses around the mid-section MS and forms a wall
surrounding
the post 20. As should be understood, the fill composition further fills the
grooves 21A,
21B during the pouring process. The term "pour" is used for the introduction
of the fill
composition into the mold, and is intended to encompass any method of
introducing a
fill composition into the mold in a liquid or other fluent form. It is
important that the fill
composition be fluent because otherwise, the fill composition will not
intersperse around
that area defined as the mid-section MS and the grooves 21A, 21B.
Fig. 7 shows an alternate embodiment of pouring the protective sleeve 23' to
the mid-
section MS of the posts 20' as described. In Fig. 7, post 20' includes at
least one groove
21' that vertically extends the approximate length of the mid-section MS,
where an
upper end 21A' of the groove being just below an upper point P1 of the mid-
section MS,
and the lower end of the groove 21B' being approximately adjacent or just
above point
P2 of the mid-section MS. The sleeve 23' may extend a slightly greater or
lesser
distance than the illustrated and described distance from P1 to P2.
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Fig. 8 is a second alternative embodiment illustrating a post 20" having a
plurality of
vertically aligned notches 21" with the upper most notch designated as 21A"
being just
below an upper point P1 of the mid-section MS, and the lower most notch
designated as
21B" being just above point P2 of the mid-section MS. As with the other
described
embodiments, the sleeve 23" may extend a slightly greater or lesser distance
than the
illustrated and described distance from P1 to P2.
Although the description above contains many specificities, these should not
be
construed as limiting the scope of the invention but as merely providing
illustrations of
some of the presently preferred embodiments of this invention. Thus the scope
of the
invention should be determined by the appended claims in the formal
application and
their legal equivalents, rather than by the examples given.
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