TECHNICAL FIELD

The present invention relates to a sludge removal pump. More specifically it relates to a sludge removal pump for the mechanical conveyance of sludge type sediment deposits that can accumulate on the bottom inside of large storage tanks, such as crude oil or other storage tanks or other settlement ponds or reservoirs or any other location, sediment trap or containment space.

BACKGROUND ART:

Over time, sediment or sludge collects on the bottom of large liquid storage tanks such as those used to store crude oil or any other liquid containment situation be it a tank or a pond or simply a receptacle of a sludge type material. This sludge type material needs to be removed periodically or regularly to maximize use of the available volume, reduce the impurities in the stored liquid or to inspect the tank floor and to facilitate follow up maintenance as required.

There are two common procedures for sludge removal. One is to remove the stored liquid (drained or pumped out) from above the sedimentary sludge. The sludge may then be removed in its 'pure undiluted' form by mechanical or manual methods. Current practice in New Zealand and still common elsewhere in the world is for the heavier sludge, in a tank bottom situation, to be handled by manual methods. Lighter sludge's can be manually moved across the tank floor by mops and squeegees for conventional suction pump removal. The removal of the heavier thicker sludge usually involves the manual shoveling of the sludge off the tank floor into appropriate bins or other containers which are then manually passed, carried or rolled on conveyors to a manhole in the side near the bottom of the tank or lifted up through a roof access opening. The bins are then emptied outside the manhole into other forms of materials handling systems to get the sludge away for further processing or disposal. In an open pond situation the sludge may be excavated by a mechanical digger. The second common procedure is to liquefy the sludge to create a slurry that can be readily pumped or vacuum sucked away. The liquefying may be by sluicing, mechanical agitation with residual or added liquid or some other mechanical, thermal or chemical liquefying process.

One disadvantage of the manual procedure is that it is dangerous to the health of personnel involved with the cleaning. The health danger is associated with the sludge itself which may have significant levels of toxic substances as well as creating slippery conditions on the inside of the storage tank. In addition, personnel involved with tank cleaning may suffer secondary health affects such as allergic reactions to the sludge.

In addition, as well as being labour intensive and slow, this increases the financial costs to a tank owner or operator. The financial cost of the tank cleaning process is not only due to the cost involved in payment of labour to clean the tanks but also due to lost revenue when the tank is inoperative during the cleaning process.

A major disadvantage of the second common procedure is the increase in volume of the problem sludge material by adding fluid to create the liquid slurry. This in effect increases the major cost of treatment or disposal of the material Sludge removal pumps for use in such situations are known. However there are a number of shortcomings with current commercially available pumps. These can include the inability for the pump to run dry without damaging the pump, the inability of the pump or other systems to self prime and the lack of ability of the pump valves to handle entrained objects such as stones, cloth rags and similar or fibrous and or gritty component or debris, poor suction characteristics and or poor discharge (head) pressures

OBJECT OF THE INVENTION

It is an object of the invention to provide a sludge removal pump that addresses the problems of the prior art, such as those discussed above. The invention will create a flow of a wide range of problem sludge type material that can be directed through a conduit to another location.

Alternatively, it is an object of the invention to at least provide the public with a useful choice for pumping sludge type materials.

DISCLOSURE OF THE INVENTION According to a first aspect of the present invention there is provided a sludge removal pump which comprises:

• a hollow body comprises an inlet and an outlet;

• at least one actuator configured to move sludge within the hollow body from the inlet to the outlet; · at least one inlet valve positioned in the hollow body and proximal to the inlet and

configured to prevent back flow of sludge out of the hollow body; • at least one outlet valve positioned in the hollow body and proximal to the outlet and configured to prevent back flow of sludge back into the hollow body;

• at least one actuator valve positioned between the inlet valve and the outlet valve and configured to prevent back flow of sludge within the hollow body wherein the inlet valve, outlet valve and piston valve comprise

• a valve seat comprising a first cutting edge; and

• at least one valve member configured to open and close when required and comprising a second cutting edge wherein the first and second cutting edges cooperate to cut through any waste material trapped between the valve seat and the valve member.

For the purposes of the specification the term "sludge" refers to a settled suspension left from stored industrial fluids such as crude oils or wastewater.

Preferably, the hollow body is an elongate cylinder.

Preferably, the at least one valve member is a pair of hinged flaps.

More preferably, the hinged flap also comprises a rubber lip configured to aid in sealing against the valve seat if the hinged flap fails to fully contact the valve seat.

Preferably, the sludge pump apparatus also comprises a feeder device connected anterior to the inlet of the hollow body and configured to direct sludge to the interior of the body.

Preferably, the sludge removal pump also comprises at least one clamp configured to realisably disconnect portions of the hollow body to allow easy access to the inlet valve, outlet valve and/or actuator valve.

In this way the hollow body can be easily dismantled for maintenance purposes should any of the valves become in operational.

BRIEF DESCRIPTION OF THE FIGURES

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1a: shows a side view of one embodiment of the present invention in the form of a single pump sludge removal pump; Figure 1b: shows a plan view of the embodiment shown in Figure 1 ; shows a front view of the embodiment shown in Figure 1 ; shows a back end view of the embodiment shown in Figure 1 ; shows a sectional view of the main body of the embodiment shown in Figure 1 ; shows a top perspective photographic view of a one-way valve for use in the embodiment shown in Figure 1 with the valve members shut; shows a top perspective photographic view of another embodiment of a one-way valve for use in the embodiment shown in Figure 1 with the valve members open; and shows a top perspective photographic view of another embodiment of the present invention in the form of a twin body sludge removal pump.

DETAILED DESCRIPTION OF THE INVENTION

The present invention addresses the problems identified in the prior art above of low efficiency of sludge removal, such as sediment sludge from surfaces such as storage tank floors in terms of time and costs, high risk of health and safety danger, high risk of environmental pollution and the inability of current sludge removal pump to run dry, self prime and to handle non- compressible entrained objects such as stones, cloth rags and the like.

The invention is now described in relation to a first preferred embodiment of the present invention as shown in Figures 1a to 2. It should be appreciated that the invention may be varied from the Figures without departing from the scope of the invention.

Referring to Figures 1 to 2 a single pump sludge removal pump in the form of a single pump version is generally indicated by arrow 1. The sludge removal pump 1 has a hollow elongated cylindrical body 2. The body is stabilised on a floor surface by feet 2a. The body 2 has an inlet 3 and outlet 4. A removable feeder device in the form of a hopper 100 is attached to the inlet 3 and into which sludge material can be easily manually fed into the inlet. The hopper 100 is stabilised on a floor surface by a foot 100a. A removable debris screen 100b fitted to the mouth of the hopper 100 prevents large extraneous solid objects falling into the inlet 3. Optionally a additional mouth shute of appropriate size can be attached to the mouth of the hopper 100 to improve the ease of loading of sludge material into the hopper 100.

The apparatus 1 has an actuator 5 in the form of a hydraulic cylinder which provides motive force to the sludge material in the body 2 from inlet 3 to outlet 4. The actuator 5 comprises a piston plunger 5a which moves within a cylinder body 5b (as shown on Figure 2). A pressurized hydraulic oil supply hose 6 and return hoses 7 from an external hydraulic power supply system (not shown) are connected to control box 8 comprises a valve system to provide alternating flow of oil pressure to the actuator 5. A discharge connector 9 is connected to the outlet 4. The actuator 5 has an extended piston rod 16 which extends into cylinder 2. Piston head 15 is hollow and configured to attach to piston rod 16 and to house an actuator valve 14. Piston head 15 is fitted with piston seals 15a to provide a sliding seal between the piston 5 and the inside of body 2. These seals are of a material to suit the particular material to be pumped and the requirements of the particular immediate environment. A common piston seal material is a self lubricating polymer which allows the pump to safely 'run dry'. Connection 16a connects the piston rod 16 with the piston head 15.

The apparatus 1 can be easily dismantled via clamps 10 to allow access to the piston 15 or the valves 12 and 13 for maintenance. The apparatus 1 can be lifted via lifting eyes 11 (shown on Figures 1A and 1 B). The apparatus 1 comprises three one-way valves in the form of inlet valve 12 positioned in the body 2 and proximal to the inlet 3; outlet valve 13 positioned in the body 2 and proximal to the outlet 4; and actuator valve 14 positioned in the piston head 15 between the inlet valve 12 and outlet valve 13. It has been found with trial and error that this arrangement of the three valves

12, 13, 14 improved the ability for the apparatus 1 to pass significant solid items e.g. stones which may become entrained in the apparatus 1.

Referring to Figures 3 and 4, each valve 2, 13, 4 comprises a valve seat 12a, 13a, 4a respectively and a (pair of independently) hinged valve flap(s) 12b, 13b and 14b respectively. The hinged flap(s) 12b, 13b and 14b move via hinge(s) 12c, 13c and 14c and are biased against the corresponding valve seat 12a, 13a, 14a to seal the valve 12, 13, 4 to prevent backflow of sludge within the body 2. When the valve flap(s) 12b, 13b and 14b are open they provide for unrestricted flow of sludge through the valve seat 12a, 13a, 14a. .

The hinged flaps 12b, 13b and 14b comprise a first cutting edge 200 across the contact line of each flap 12b, 13b and 14b. A second cutting edge 250 is repeated on the valve seats 12a, 13a and 14a extending proximal to the hinge 12c, 13c and 14c (as shown in Figure 4). The cutting edges 200 and 250 are configured to cut through non-compressible sludge (such as fibrous material in form of organic matter or rags) which has become entrained between the valve seat 12a, 13a, 14a and the flap(s) 12b, 13b and 14b and which would prevent sealing the valves 12,

13, 14 and therefore allow the reverse passage of sludge material from the required flow direction. This cutting action prevents clogging of the valves. The arrangement of three valves creates a flushing effect to the passage of debris within the apparatus 1 should any of the three valves be clogged with solid debris and also aids the pump to self prime at start up or if the supply of sludge is interrupted during operation. The inlet 12 and outlet valve 13 are assembled in the pump 1 as a component of the connection that includes a clamp 10 at the inlet 3 and at the outlet 4. Actuator valve 14 may be fitted by a screw thread 300 into the piston 15 (as shown in Figure 3) or may be press fitted onto a receiving rim (not shown) in the body 2. Optionally, the first cutting edge 200 may include or consist of a rubber lip to aid in sealing of each valve flap 12b, 13b and 14b against the valve seat 12a, 13a, 14a.

A person skilled in the art will appreciate that the size of the apparatus 1 can be varied without departing from the scope of the present invention depending upon its application. Figure 5 shows another embodiment of the sludge removal pump 1 in the form of a twin body 2 apparatus mounted on a pair of wheeled caterpillar tracks 400 to provide good mobility over a floor surface. The caterpillar tracks 400 are driven by individual variable speed hydraulic motors (not shown) to drive the apparatus forward to enable progressive sludge removal over an area and to enable full manoeuvring as required. A feeder device in the form of a horizontally rotating feed drum 500 comprising an Archimedes screw profiling 510 is configured to channel sludge material from the floor surface to the inlets 3 of the bodies 2. The vertical height of the feed drum 500 is adjusted in relation to a floor surface via legs 520.

The feeder drum 500 is wider than the width of the body 2 of the sludge removal pump 1 to give a maximum operating swath of the overall apparatus as it is driven across a floor. The feeder drum 500 lies across the front of the sludge removal pump in very close proximity to a floor surface and is the first component to start the handling of the sludge. Spray applicator nozzles (not shown), can spray a diluting liquid on to the rotating feeder drum 500 to aid the pumping of a drier or very thick sludge. Spray applicator nozzle are connected to a fluid source and pump (not shown).

A frame 530 shown in Figure 5 prevents oversize debris or other large objects from contacting the rotating feeder drum. This configuration of two pumps 2 is desirable to give greater throughput and a more steady flow of sludge.

In use, the piston strokes forward (in the direction of arrows A as shown in Figures 1A, 1 B and 5) and back under the motive power provided by the actuator 5. Thick non-compressible sludge such as sediment sludge from a crude oil storage tank bottom is harvested either by manual input into a hopper 100 or mechanical collection with a rotating feed drum 500 or by direct connection via a pipe or simple submersion in deep sludge or some other method and channelled through inlet 3 into the body 2 of the apparatus 1. The sludge is drawn through item 3 and one-way inlet valve 12, then forced through piston 14 and outlet 13, from the motive force provided by actuator 5. During the power stroke in the direction of flow, the actuator valve 14 closes and the inlet valve 12 and outlet valve 13 opens to suck more sludge into the inlet 3 and forcibly discharge sludge through the outlet 4. Conversely, during the return stroke of the actuator 5, the actuator valve 14 opens and the inlet valve 12 and outlet valve 13 close to forcibly transfer more sludge through the actuator valve 14 of the apparatus 1. During the return stroke no sludge enters or leaves the apparatusl

The pumped sludge is then discharged to a remote location via a hose or pipe connected to the discharge connector 9.

The present invention offers notable advantages over the prior art by including in a single apparatus:

• Improved ease of use in pumping sludge material from a location through improved reliability and in the event of malfunction allows easy dismantling providing improved and rapid servicing and maintenance.

• The ability to handle a wide range of soft and hard debris.

• A very high suction ability enabling very thick sludge to be drawn into the pump body.

• A very high discharge pressure capability giving the ability to deliver the very thick

sludge materials further along a discharge pipe.

· The ability to 'self prime'.

• The ability to run dry (no lubrication by passing sludge of the moving piston 15)

• Improved speed and efficiency of collecting and removing thick sludge material from a floor surface with a resultant cost benefit to the user.

• Reduced costs or environmental risk over known methods of sludge pumping such as use of large volumes of dilutant fluids or chemicals.

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred

embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.