U.S. patent application number 13/322866 was filed with the patent office on 2012-05-24 for sludge extraction apparatus and method.
This patent application is currently assigned to TYCO FLOW SERVICES AG. Invention is credited to Mark Krohn.
Application Number | 20120125441 13/322866 |
Document ID | / |
Family ID | 43355586 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120125441 |
Kind Code |
A1 |
Krohn; Mark |
May 24, 2012 |
SLUDGE EXTRACTION APPARATUS AND METHOD
Abstract
There is provided sludge extraction apparatus (10) including a
collection pipe (13) having a plurality of spaced, a suction pump
(23), a suction pipe (15) with an end connected to the suction pump
(23) and a suction head assembly (16) connected to the other end
and slidable through the collection pipe (13) from an end, the
suction head assembly (16) including a leading body portion (17)
spaced from and connected to a trailing body portion (21) having an
axial bore (19) connected to a suction pipe (15), the leading (17)
and trailing (21) body portions substantially occluding the
collection pipe (13) in use and defining there between a suction
zone (22) of a length selected to open to at least one said opening
at selected positions of the suction head assembly along the
collection pipe.
Inventors: |
Krohn; Mark; (Caboolture,
AU) |
Assignee: |
TYCO FLOW SERVICES AG
Schaffhausen
CH
|
Family ID: |
43355586 |
Appl. No.: |
13/322866 |
Filed: |
June 18, 2009 |
PCT Filed: |
June 18, 2009 |
PCT NO: |
PCT/AU2009/000780 |
371 Date: |
December 13, 2011 |
Current U.S.
Class: |
137/1 ;
137/565.23 |
Current CPC
Class: |
E02F 5/28 20130101; E02F
3/8816 20130101; Y10T 137/0318 20150401; Y10T 137/86083 20150401;
E02F 3/8875 20130101 |
Class at
Publication: |
137/1 ;
137/565.23 |
International
Class: |
E03B 5/00 20060101
E03B005/00 |
Claims
1. Sludge extraction apparatus including: a collection pipe having
a plurality of openings through the wall thereof at selected
spacings; a suction pump; a suction pipe having one end connected
to the suction pump; a suction head assembly connected to the other
end of the suction pipe and slidable through the collection pipe
from one end thereof, the suction head assembly including a leading
body portion spaced from and connected to a trailing body portion
having an axial bore connected to a suction pipe, the leading and
trailing body portions substantially occluding the collection pipe
in use and defining therebetween a suction zone of a length
selected to open to at least one said opening at selected positions
of the suction head assembly along said collection pipe.
2. Sludge extraction apparatus according to claim 1, wherein the
collection pipe is of a polymer material or composite thereof.
3. Sludge extraction apparatus according to claim 2, wherein the
polymer is HDPE.
4. Sludge extraction apparatus according to claim 1, wherein the
apertures are selected from single apertures spaced in a line along
the pipe and apertures arranged in groups around the pipe with the
groups spaced along the pipe.
5. Sludge extraction apparatus according to claim 4, wherein the
apertures are in groups and the apertures are elongate in the
direction of the pipe axis to preserve cross section for a given
aperture area.
6. Sludge extraction apparatus according to claim 1, wherein the
collection pipe is permanently installed in a sludge pond or
pit.
7. Sludge extraction apparatus according to claim 1, wherein the
collection pipe is relocatable in a sludge pond or pit.
8. Sludge extraction apparatus according to claim 1, wherein the
selected spacing of the apertures comprises even spacing.
9. Sludge extraction apparatus according to claim 1, wherein the
suction pump is selected from positive displacement pumps.
10. Sludge extraction apparatus according to claim 1, wherein the
suction pump is a compressed air operated venturi vacuum/pressure
cycle pump.
11. Sludge extraction apparatus according to claim 1, wherein the
suction pump is mobile or transportable.
12. Sludge extraction apparatus according to claim 1, wherein the
suction pipe is formed of polymer or polymer composite.
13. Sludge extraction apparatus according to claim 1, wherein the
connection of the suction pipe to the suction pump is a rotating
coupling to the suction pump associated with a spooler, whereby the
suction pipe may be spooled on and off the spooler.
14. Sludge extraction apparatus according to claim 13, wherein the
spooler is co-mounted with the suction pump to form a transportable
assembly.
15. Sludge extraction apparatus according to claim 1, wherein the
suction head assembly runs at a working clearance in to bore while
maintaining a substantial occlusion to the bore of the pipe
separating the suction zone from the collection pipe upstream and
downstream of the suction head assembly.
16. Sludge extraction apparatus according to claim 1, wherein the
leading and trailing body portions are each of plastic construction
selected from cast resin, thermoplastic moulding, and a
free-machining polymer.
17. Sludge extraction apparatus according to claim 1, wherein the
leading body portion is spaced from the trailing body portion by
being integrally formed with interconnecting web portions.
18. Sludge extraction apparatus according to claim 1, wherein the
leading body portion and the trailing body portion comprise
respective leading and trailing members spaced apart and
interconnected by one or more interconnecting strut members.
19. Sludge extraction apparatus according to claim 1, wherein there
is provided an equalization port passing through the leading body
portion and connecting the suction zone to the collection pipe
ahead of the suction head assembly.
20. Sludge extraction apparatus according to claim 19, wherein the
port is a substantially axial equalization port between the suction
zone and the collection pipe ahead of the suction head
assembly.
21. Sludge extraction method including the steps of: installing
into the bottom of a settling pit, pond or the like a collection
pipe having a plurality of openings through the wall thereof at
selected spacings; connecting a suction pump to one end of a
suction pipe; connecting a suction head assembly including a
leading body portion spaced from and secured to a trailing body
portion to the other end of the suction pipe by an axial bore
through the trailing body portion; inserting the suction head
assembly into an open end of the collection pipe, whereby the
leading and trailing body portions substantially occlude the
collection pipe and define a suction zone therebetween of a length
selected to open to at least one said opening at substantially all
positions along said collection pipe; and moving said suction head
assembly through the bore of said collection pipe while operating
said suction pump to draw sequentially through said openings.
Description
[0001] This invention relates to a sludge extraction apparatus and
method.
[0002] This invention has particular but not exclusive application
to a sludge extraction apparatus and method for extraction of
sludge from palm oil waste settling ponds, and for illustrative
purposes reference will be made to such application. However, it is
to be understood that this invention could be used in other
applications, such as pit sludge extraction generally.
PRIOR ART
[0003] Unless explicitly indicated to the contrary, none of the
following prior art constitutes common general knowledge in the
art.
[0004] In the conventional processes for extraction of palm oil
from oil palm kernels, a waste stream is generated including water
and fibrous and other particulate organic materials, dirt and other
minerals, filter cakes and the like. The wastes are piped to lined
or unlined open pits where the waste undergoes environmental
degradation to produce CO.sub.2 and other digestion gases and a
sludge residue. Periodically the sludge requires removal. In more
recent times covered pits have been used as part of a carbon
capture program. The pits are covered by a membrane that sits on
top of the liquid medium in the pit. Once the membrane is in place
the access to de-sludge is limited.
[0005] One method used to manage sludge removal in covered pits is
installing a fixed manifold of perforate collection pipes in the
bottom of the pit. Periodically suction is applied to the manifold
to extract sludge. This fixed manifold arrangement has its
limitations due to suction efficiency falling off with distance in
the pit, as the apertures closer to the suction pump draw liquid
with little entrained sludge at the expense of suction at the
remoter apertures. The sludge can maintain a significant batter
angle about the apertures, thus permitting considerable fluid flow
for limited sludge recovery.
[0006] One attempt to overcome these disadvantages uses a
"pipe-in-pipe arrangement where the suction pipe arrangement
comprises an outer, perforate sleeve located on the floor of the
pit and into which is progressively slid a suction tube. The
suction tube is fed from and retrieved to a rotating drum which
terminates the suction tube to a rotating coupling to a suction
pump. The head or suction nozzle of the suction tube depresses the
space in the outer sleeve ahead of the head or suction nozzle only.
In use, the suction tube is fed through the perforate sleeve (with
suction to effect sleeve clearance and aid feeding). Thereafter the
suction tube is withdrawn under suction, the plug effect of the
head or suction nozzle meaning that the suction is confined to the
perforate sleeve portion ahead of the head or suction nozzle.
[0007] The disadvantage is that at any point in the outer,
perforate sleeve the nozzle is attempting to depress the pressure
in the whole of the sleeve ahead of the nozzle. Suction efficiency
falls off with distance from the nozzle but inefficient suction at
a distance robs the suction zone near the nozzle of power.
DESCRIPTION OF INVENTION
[0008] As used herein the word "comprising" and its parts is to be
taken as non-exclusive, unless context indicates clearly to the
contrary. This invention in one aspect resides broadly in sludge
extraction apparatus including:
[0009] a collection pipe having a plurality of openings through the
wall thereof at selected spacings;
[0010] a suction pump;
[0011] a suction pipe having one end connected to the suction
pump;
[0012] a suction head assembly connected to the other end of the
suction pipe and slidable through the collection pipe from one end
thereof, the suction head assembly including a leading body portion
spaced from and connected to a trailing body portion having an
axial bore connected to a suction pipe, the leading and trailing
body portions substantially occluding the collection pipe in use
and defining therebetween a suction zone of a length selected to
open to at least one said opening at selected positions of the
suction head assembly along said collection pipe.
[0013] The collection pipe may be of metal, polymer or composite.
The collection pipe should be selected to substantially maintain
its form under the expected pressure gradient. Accordingly
elastomeric composite pipe such as fabric reinforced rubber is
preferably wire reinforced against collapse. In view of the
chemically aggressive environment in some settling ponds, metal
collection pipe is preferably coated with a chemically resistant
coating such as thermally bonded polyethylene or epoxy coating.
Advantageously the collection pipe is formed of a stock engineering
thermoplastic such as HDPE.
[0014] The apertures may be single apertures spaced in a line along
the pipe. Alternatively the apertures may be arranged in groups
around the pipe with the groups spaced along the pipe. The
apertures may be any suitable shape. For example, where the
apertures are in groups the apertures may be elongate in the
direction of the pipe axis to preserve cross section for a given
aperture area.
[0015] The collection pipe may be permanently installed in the
sludge pond or pit, or may be removable, or at least relocatable,
in the pit.
[0016] The selected spacing of the apertures may comprise even
spacing or may be uneven spacing. For example the spacing may be
selected whereby a single aperture or group of apertures are open
to the suction zone and any given position of the suction head
assembly in the collection pipe. Alternatively, the collection pipe
may traverse areas of lesser or greater deposition of solids,
wherein there may be advantage in two or more apertures or groups
of apertures being exposed to the suction zone simultaneously.
[0017] The suction pump may take any form suitable for handling the
sludge or entrained particulates to be settled. The suction pump
may be selected from positive displacement pumps such as
peristaltic pumps or impeller pumps. In the alternative, the
suction pump may comprise a compressed air operated venturi
vacuum/pressure cycle pump. The pump may be a fixed installation or
may be mobile or transportable. The pump may be powered by
independent power or from mains. An independently powered pump may
be powered by an internal combustion engine providing direct drive
or indirect drive. Indirect drive may be hydraulic or pneumatic. In
the case of a compressed air operated venturi vacuum/pressure cycle
pump, this may be associated with a mobile compressor pack or may
be co-mounted with a compressor.
[0018] The suction pipe may take any suitable form. The suction
pipe may be formed of polymer or polymer composite. The suction
pipe should be selected to substantially maintain its form under
the expected pressure gradient. Accordingly elastomeric composite
pipe such as fabric reinforced rubber is preferably wire reinforced
against collapse. Advantageously the suction pipe is formed of a
stock engineering thermoplastic such as HDPE.
[0019] The connection of the suction pipe to the suction pump may
be a direct, fixed union. However, in order that the suction pipe
may be spooled on and off a spooler, the suction pipe is preferably
connected to a rotating coupling to the suction pump associated
with the spooler. The spooler is preferably co-mounted with the
suction pump to form a transportable assembly.
[0020] The suction head assembly may be close fitting to the bore
of the collection pipe and accordingly rely on low friction
surfaces and/or water lubrication to slide freely. However, it is
not necessarily so and the suction head assembly may run at a
working clearance in to bore while maintaining a substantial
occlusion to the bore of the pipe separating the suction zone from
the collection pipe upstream and downstream of the suction head
assembly. The connection of the suction head assembly may be a
fixed coupling or may be a rotatable coupling.
[0021] The leading and trailing body portions may be of the same or
different materials and may be selected from metal and plastic
construction. For example, the respective portions may be formed of
cast resin or thermoplastic moulding, or formed from a
free-machining polymer such as DELRIN.RTM.. The leading body
portion may be spaced from the trailing body portion by any
suitable means consistent with providing an open suction zone
therebetween. For example the leading and trailing body portions
may be integrally formed with interconnecting web portions.
Alternatively the leading and trailing portions may be leading and
trailing members interconnected by one or more interconnecting
strut members. In the case of leading and trailing portions of
suitable material, the strut members may comprise an array of two
or more metal rods threaded or otherwise affixed at their ends to
the respective body members.
[0022] The interconnection may comprise a hollow tubular member in
communication with the suction pipe via the trailing body member
and having wall apertures whereby the suction zone may be
depressed. Otherwise, the trailing portion or member may have an
axial bore or other passage therethrough connecting the suction
pipe with the suction zone directly.
[0023] The suction zone defined between the leading and trailing
body portions is of a length selected to open to at least one
collection pipe opening at substantially all positions along the
collection pipe as described above. At certain points along the
collection pipe there may be places or circumstances where the
depression invoked by the suction pump needs to be relieved
somewhat to avoid stalling the pump. In addition, to advance the
suction head assembly along the collection pipe, it may be
desirable to reduce resistance to movement ahead of the suction
head assembly. To this end there may be provided an equalization
port passing through the leading body portion and connecting the
suction zone to the collection pipe ahead of the suction head
assembly. For example there may be provided a substantially axial
equalization port between the suction zone and the collection pipe
ahead of the suction head assembly.
[0024] In a further aspect this invention resides broadly in a
sludge extraction method including the steps of:
[0025] installing into the bottom of a settling pit, pond or the
like a collection pipe having a plurality of openings through the
wall thereof at selected spacings;
[0026] connecting a suction pump to one end of a suction pipe;
[0027] connecting a suction head assembly including a leading body
portion spaced from and secured to a trailing body portion to the
other end of the suction pipe by an axial bore through the trailing
body portion;
[0028] inserting the suction head assembly into an open end of the
collection pipe, whereby the leading and trailing body portions
substantially occlude the collection pipe and define a suction zone
therebetween of a length selected to open to at least one said
opening at substantially all positions along said collection pipe;
and
[0029] moving said suction head assembly through the bore of said
collection pipe while operating said suction pump to draw
sequentially through said openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order that this invention may be more readily understood
and put into practical effect, reference will now be made to the
accompanying drawings which illustrate a preferred embodiment of
the invention and wherein:
[0031] FIG. 1 is a side view of a suction head assembly for use in
apparatus in accordance with the present invention;
[0032] FIG. 2 is a view of apparatus in accordance with the present
invention, deployed in use;
[0033] FIG. 3 is a plan view of apparatus in accordance with the
present invention;
[0034] FIG. 4 is a side view of apparatus in accordance with the
present invention;
[0035] FIG. 5 is an end view of apparatus in accordance with the
present invention, with carriage retracted; and
[0036] FIG. 6 is an end view of apparatus in accordance with the
present invention, with carriage extended.
DESCRIPTION OF THE EMBODIMENT(S)
[0037] In the figures, there is provided a pipe-in-pipe sludge
clearance apparatus 10 for periodically removing sludge from a pit
11 having a cover 12. The sludge clearance apparatus 10 includes an
indwelling or installed collection pipe 13 having O50 mm apertures
14 evenly spaced at 1000 mm centres along it, and a HDPE suction
pipe 15 able to be fed into the installed collection pipe 13. The
suction pipe 15 is terminated by a suction assembly 16 including a
leading pig 17 having an axial equalization port 20 and spaced from
and secured to a trailing pig 21 by stainless steel rods 18. The
trailing pig 21 has an axial bore 19 providing connection to the
suction pipe 15, the pigs 17, 21 defining a suction zone 22 of 940
mm length between them.
[0038] When the leading pig 17 passes each of the apertures 14 in
the collection pipe 13 over the portion deployed on the bottom of
the covered sludge pit 11, the suction zone 22 concentrates the
suction at the holes in turn. The 940 mm length of the suction zone
maximizes the residence time of the zone over the hole as the
suction assembly is advanced.
[0039] The collection pipe 13 is 90 mm NB with the holes in the
base (underside) only. The suction pipe 15 is 75 mm OD. The
diameter of the head and tail are selected to provide a 1.5 mm
clearance on the collection pipe 13 bore.
[0040] An air operated vacuum/pressure pump 23 is connected to the
centre of a suction pipe spool 24 via a swivel fitting 25. Vacuum
is applied to the suction assembly 15 by the pump 23, depressing
the suction zone. A small amount of vacuum is directed via the 13
mm axial equalization port 20 to clear the collection pipe 13 as
the suction assembly 15 moves forward. The feed rate is about 1
metre per minute or 3-4 full cycles for a typical air operated
vacuum/pressure pump 23 operating at 25''Hg and 100 litres each
cycle.
[0041] The drop off of the vacuum caused by the 13 mm axial
penetration in the cap is negligible compared to the suction
confined to the single 50 mm aperture. Almost full vacuum is
applied to the 50 mm penetration for the duration of the pass, the
combination of vacuum and pressure supplied by the typical 6+ metre
head of the pond itself results in excellent inflows.
[0042] The pump 23 is conveniently mounted on a wheeled chassis 26
which also mounts the suction pipe spool 24. The spool 24 is
reversibly driven to deploy and retrieve the suction pipe 15. The
wheels 27 of the chassis 26 are retractable to provide stability in
use. A diesel powered air compressor 30 stages drives the pump 23.
Fire extinguishers 31 are mounted. The front wheels 33 are
steerable.
[0043] It will of course be realised that while the above has been
given by way of illustrative example of this invention, all such
and other modifications and variations thereto as would be apparent
to persons skilled in the art are deemed to fall within the broad
scope and ambit of this invention as defined in the following
claims.
* * * * *