AU2002302174B2 - Sump assembly - Google Patents

Description

WO 02/097204 PCT/AU02/00685 -1- Sump Assembly' Field of the Invention This invention relates to a sump assembly. In particular the invention concerns a sump assembly for removing spilt fluids from a processing plant.

Background Art All processing plants must ensure that safe operating conditions prevail throughout the plant. This requires planning and the implementation of appropriate safety strategies in case an undesired event takes place. One such strategy is aimed at keeping the floor surface free of fluid, particularly slurries, which may result from a spillage.

Processing plants are often prone to such fluids and other material spilling from tanks and the like and creating a hazard on the floor surface of the workplace.

These spillages generally drain towards a sump or hole in the floor structure, before being pumped to a recovery plant in the process stream.

One of the first items designed and constructed in a plant is the earth and civil works. These works generally do not take into consideration the need of a cavity for the installation of the pump. As such it is later necessary to excavate the cavity and insert a concrete pipe, or form and. cast concrete in situ. The selected pump can then be installed together with the required supporting framework and intake filters to prevent the ingress of larger solid objects entering the sump.

When constructing a new plant, one of the last items installed and commissioned are the pumps and associated apparatus for the sumps. Therefore, there is no means to remove fluid resulting from a spillage which may occur during the initial commissioning of other parts of the plant.

Installations currently used for removing spilt fluids have a filter which prevents unwanted material entering the sump. Such unwanted material includes wood, WO 02/097204 PCT/AU02/00685 -2rags, gloves and plastic which unfortunately tend to become wedged in the filter.

These obstructions often act as a dam, preventing fluid entering the sump and creating a build-up of the fluid on the floor. This build-up often consists of slippery effluents which creates a hazard for operators in the plant.

To overcome such blockages operators use a hose to squirt the effluent through the mesh. This however results in the sump filling with water and dramatically diluting the fluid which has been spilt, as well as increasing the amount of fluid which needs to be removed from the sump. The pump must then run for unnecessarily long periods of time to remove this excess water.

Alternatively, the operator removes the mesh all together and shovels the spillage, inclusive of any other material, into the sump. This causes the pump and pipeline to block due to the oversized items which, if the filter was in place, would not enter the sump.

Once in the sump, any additional water and/or oversized particles are pumped to the recovery plant in the process stream. This results in large cyclical problems in the process including excessive power costs, loss of valuable minerals, plant blockages and unnecessary maintenance.

Another drawback of the current installations is that the pump cannot remove all of the fluid from the sump as some fluid is at a level below the level of the pump intake. This is a particular problem when the fluid is a slurry, as the solid constituents of the slurry will settle to the bottom. Once settled the solids become very difficult to remove. Gradually the percentage of solids remaining in the bottom increases, preventing the efficient operation of the pump. The increase in the density of the slurry in the sump may also lead to blocking of the pump and the downstream pipelines.

Furthermore, current installations are constructed from different components insitu. It is therefore necessary to transport all the components to the cavity in the floor and assemble each component before commissioning may take place.

When a certain component needs maintenance it may be necessary to strip the WO 02/097204 PCT/AU02/00685 -3assembly down in order to carry out the maintenance required or to replace that particular component.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia as at the priority date of the application.

It is against this background, and the problems and disadvantages associated therewith, that the present invention has been developed.

Disclosure of the Invention The present invention provides a sump assembly for collecting and discharging spilt fluids from a floor surface in a processing plant, the sump assembly comprises a casing adapted to be received in a cavity in a floor structure; a pump received and supported in the casing; a gap between the casing and the pump to allow fluid to enter the casing; a first filter located equal to or below the top of the casing and extending across the gap between the inner wall of the casing and the pump; and a second filter located below the first filter; whereby the fluid enters the sump assembly through the gap and passes successively through the first and second filters into the lower regions of the casing, before being discharged from the casing by the pump.

In contrast to the prior art the present invention provides a packaged unit capable of being readily and quickly installed in a cavity. The sump assembly's WO 02/097204 PCT/AU02/00685 -4configuration is such that it may be placed directly into a cavity in the floor structure and immediately commissioned. It also assists in standardising the various assemblies used in applications for removing spilt fluids.

Furthermore, the sump assembly's construction allows it to be easily maintained and quickly replaced if the unit is faulty.

Preferably the cavity is equal or greater in size than the outer dimensions of the casing. A suitable material may be used to fill in the space between the cavity and the outer dimension of the casing.

Preferably the top of the casing is level with the floor surface.

The casing may be secured to the floor structure.

The casing may have a securing means extending radially outward from the top of the casing for securing the sump assembly to the floor structure.

The casing may have a lower section frusto-conical in shape. Preferably the lower section has an end wall providing a bottom for the casing.

Preferably the first filter is below the top of the casing allowing any spilt fluid to be received therein.

The first filter may be removable from the sump assembly to allow cleaning.

Preferably the first filter comprises a body and a handle for removal purposes, wherein the body comprises a bottom, four sides and an open top to define a filter chamber. The bottom and sides may have staggered apertures for trapping solids and preventing them passing through. Preferably the apertures are slots having round ends.

The filter chamber provides a section which contains the solid articles not suitable for pumping. These solid articles are at a level which would not block the entrance of the fluid into the casing, and therefore not create a damming effect of WO 02/097204 PCT/AU02/00685 the fluid around the casing. The fluid chamber is designed to be easily removed for quick disposal of the solid articles held therein.

The second filter may be fixedly connected to the casing, extending between the inner wall of the casing and the pump. As the second filter is fixedly connected, the first filter can be removed for cleaning whilst fluid is still spilling into the casing.

The second filter can then prevent the solid articles passing into the casing.

The configuration of the filters ensures that the fluid is first filtered before entering the casing. In current installations, the filter can be removed, allowing the fluid to enter the casing with solids. In practice this filter, once removed, is sometimes not replaced, leading to solids and articles not suitable for pumping to continue to enter the casing. The present invention has two filters, one removable and one fixed in position.

Preferably the second filter comprises punched plate having a plurality of staggered apertures. Preferably the apertures are slots having round ends. The slots may be sufficient in size to prevent solids, which are too large for the pump, passing through.

The slots are configured so as to minimise oversized particles becoming jammed in the filters which may prevent spilt fluids entering the casing.

Preferably the apertures of the second filter are smaller than the apertures in the first filter.

Access to the second filter for cleaning requirements is possible after the first filter has been removed.

The pump may be removably received in the casing.

A support means may support the pump in the casing.

The pump may comprise a first and second intake. Preferably the first intake is located below the second intake. The first and second intakes may each WO 02/097204 PCT/AU02/00685 -6comprise an opening having a screen located over each opening to filter and control the size of the solids entering the pump.

The pump may have a control means to operate the pump at predetermined fluid levels.

Preferably the uppermost fluid level is above the bottom of the first filter.

The pumping assembly may have an agitation means for agitation of the fluid in the lower section of the casing. The agitation means may comprise a plurality of nozzles supplied with high-pressure water. Preferably at least one of the nozzles is adapted to direct water to the first intake to remove any accumulated material, and at least one further nozzle is directed to the inner surface of the casing.

Typically the agitation means comprises four nozzles, wherein one nozzle is directed to the first intake and the remaining three nozzles are directed to the inner surface of the casing.

Preferably the agitation means has an activation means which activates and deactivates the nozzles at predetermined fluid levels.

The activation means assists in ensuring the casing and intake remain free of the permanent build-up of solids. It also ensures that, over time, the percentage of solids does not increase to an unpumpable density in the lower section. Using the activation means the percentage of solids in the lower section will remain substantially in the same range between each application.

Preferably the sump assembly also comprises a sensing means to sense the fluid levels in the casing. The sensing means may comprise a plurality of sensing probes. Preferably the sensing probes are enclosed by a housing, wherein the housing protects the probes from wear due to abrasion by the fluid whilst allowing slight movement of the fluid around the probes to prevent accumulation of the material. The sensing probes may be used to send to the appropriate signals to WO 02/097204 PCT/AU02/00685 -7activate and deactivate the various components of the sump assembly in accordance with different fluid levels during operation.

Preferably the inner surface of the casing is lined with wear resistant material.

Brief Description of the Drawings The invention will be better understood by reference to the following description of a specific embodiment as shown in the accompanying drawings in which: Figure 1 is a cross-sectional view of a sump assembly; Figure 2 is a cross-sectional view of the upper portion of Figure 1; Figure 3 is a cross-sectional view of the mid portion of Figure 1; and Figure 4 is a cross-sectional view of the lower portion of Figure 1.

Best Mode(s) for Carrying Out the Invention In Figures 1 to 5, there is shown a sump assembly in accordance with the preferred embodiment. The sump assembly 11 has a casing 13, a pump which is received in the casing 13, a first and second filter 17, 19 and an agitation means 21.

The sump assembly 11 is lowered into a cavity 22 of a floor structure 20 of a processing plant such that the top lip 14 of the casing 13 is flush with the floor surface 16. The floor surface 16 slopes downwardly towards the cavity 22 so that when a fluid is spilt the fluid flows towards the casing 13.

The casing 13 is secured to the floor structure 20 using fasteners through securing means in the form of projections 18 which extend radially outward from the top 14 of the casing 13.

WO 02/097204 PCT/AU02/00685 -8- The casing 13 comprises a lower section 23, a middle section 25 and an upper section 27. The lower section 23 is frusto-conical in shape and has an end wall 24. The lower section 23 is bolted to the middle section 25, which is bolted to the upper section 27. The inner wall 29 of the casing 13 is covered with a wear resistant material (not shown), providing wear resistance from any abrasive materials in the fluid.

The pump 15 is supported within the casing 13 by framework (not shown). The positioning of the pump 15 is such that a gap exists between the pump 15 and the casing 13, so that the fluid on the floor surface 16 can flow into the sump assembly 11.

The pump 15 has a suction pipe 51 extending downwardly from the impeller housing 52 towards the end wall 24 of the lower section 23, providing a first intake 49 at the terminating end of the suction pipe 51. The length of the suction pipe 51 is such that the first intake 49 is level with a predetermined third level 67, as discussed below.

The impellor housing 52 also incorporates a second intake 53.

The first and second intakes 49, 53 are each covered by a slotted screen 55, 56 in order to prevent oversized particles entering the pump The first and second filters 17, 19 both extend across the gap between the inner wall 29 of the casing 13 and the pump 15, so that all material entering the lower and mid sections 23, 25 of the casing 13 must first pass through each filter 17, 19.

The first filter 17 is removably supported in the upper section 27 of the casing 13.

The first filter 17 comprises a handle 33 for removing the first filter 17 from the casing 13, and a body 35. The body 35 defines a filter chamber 36 which receives the fluid, prevents oversized particles passing through and retains those particles within the chamber 36 The filter chamber 36 has four sides 37 and a bottom 39, each having an array of apertures 31 in a staggered configuration.

The apertures 31 are in the form of slots having rounded ends to minimise the WO 02/097204 PCT/AU02/00685 -9chance of solid particles becoming lodged in the apertures 31 of the filter chamber 36.

The second filter 19 is fixedly supported in the upper section 27 of the casing 13 below the first filter 17. The second filter 19 comprises a steel plate having apertures 32. The apertures 32 are smaller in size than apertures 31 incorporated in the filter chamber 36. The apertures 32 are in the form of slots having rounded ends, and are in a staggered configuration. The apertures 32 are shaped so as to minimise the chance of the second filter 19 becoming clogged with oversized particles.

The agitation means 21 comprises a distribution box 41 and four nozzles 43 (only three are shown), which are in communication with the distribution box 41. The distribution box 41 is secured to the end wall 24 of the lower section 23, and is supplied with high pressure water through a supply pipe 45. The high pressure water passes from the distribution box 41, through the nozzles 43 and into the casing 13, assisting in keeping the casing 13 free from build-up as well as maintaining a manageable percentage solid content in the casing 13..

Three of the four nozzles 43a, 43b, 43c direct the water to the sloped wall 47 of the lower section 23 which, in use, develops a rotating fluid movement. The fourth nozzle 43d directs water towards the first intake 49 of the pump 15 in order to remove any build up that may form on the screen 55, keeping the first intake 49 relatively clear of blockages.

The sump assembly also comprises fluid level sensors 57 which provide a signal to the various components of the sump assembly 11 when the fluid reaches predetermined fluid levels. The sensors 57 are housed in a shroud 59 having apertures 61, which allow the fluid to communicate with the sensors 57. The shroud 59 protect the sensors from the abrasive wear caused by the Fluid and allows fluid to move therethrough, minimising any build up on the sensors 57 which could result in a false indication as to the level of the fluid.

WO 02/097204 PCT/AU02/00685 In use, the floor surface 16 directs any spilt fluid towards the installed sump assembly 11. The fluid drops into the first filter 17, passing through the apertures 31 and onto the second filter 19. The fluid then flows through the apertures 32 of the second filter 19 and into the lower sections of the casing 13. Obviously any oversized particles will be filtered from the fluid as the fluid passes through the filters.

As further fluid flows into the casing the liquid reaches a predetermined first level 63. The sensors 57 sense the level of the liquid and activates the agitation means 21.

Once in operation, the agitation means 21 delivers high pressure water to the lower section 23 of the casing 13 through nozzles 43, producing a turbulent rotating slurry in the lower section 23. This results in any solid particles that may have settled at the bottom of the casing or that are attached to the side of the casing 13 to become suspended in the fluid.

The additional water injected into the casing 13 assists in increasing the level of the liquid above the first level 63 to a predetermined second level 65, located between the bottom 39 of the first filter 17 and the top lip 14 of the casing 13.

As the level of the liquid increases above the second filter 19 and the bottom of the first filter 17, the solid articles caught in these filters are re-suspended. This helps dislodge accumulated material in the filters, making them easier to clean, when required. The amount of additional water added to the casing 13 is such that ideal conditions are created for pumping purposes.

When the fluid reaches the second level 65, the sensors 57 activate the pump discharging the agitated fluid through discharge pipe 69.

As the liquid level drops, the fluid delivered through the agitation means 21 dilutes the fluid in the sump, further promoting the cleaning of the casing 13, the screens and the discharge pipe 69.

WO 02/097204 PCT/AU02/00685 -11 When the liquid level reaches the third level 67, which is equal with the first intake 49, the pump 15 and agitation means 21 are deactivated. The sump assembly 11 is then left in a good condition to receive fluid from further spillages.

When the first filter 17 fills with oversized objects, it may easily be removed with handle 33 and cleaned. If the first filter 17 fills during operation of the sump assembly 11, the first filter 17 may still be removed and cleaned, leaving the second filter 19 to minimise oversized particles entering the casing 13.

The casing is designed so that further sections may be added to increase the depth of the casing 13.

In the design of the sump assembly 11 the depth of the casing, the volume of water added by the agitation means 21 and the pump capabilities must be jointly considered so that the density of the fluid, particularly in the lower section 23 of the casing 21, does not exceed 55% solids content, and that the water added to the casing does not excessively dilute the fluid.

Under ideal conditions the fluid discharged by the pump has a solids concentration of 35-40%.

The sump assembly of the current invention enables the pump to work more effectively, discharging the same amount of fluid as current installations in a fraction of the time. The main contributory factor to this is the reduction in water added to the spilt fluid as well as the reduction in oversized particles entering the casing and being pumped into the system.

The sump assembly has many advantages including ease of installation and maintenance, reduction of the volume of water used, reduction in plant downtime, reduction in maintenance, reduction in power used, increase in safety conditions, and a reduction in the amount of fluid lost as the collected fluid may be pumped back into the processing facility.

WO 02/097204 PCT/AU02/00685 -12- It is to be appreciated that the scope of the invention is not to be limited to the embodiment herein described. The sump assembly is not to be limited to a particular size, shape or type of material.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims (36)

1. A sump assembly for collecting and discharging spilt fluids from a floor surface in a processing plant, the sump assembly comprises: a casing adapted to be received in a cavity in a floor structure; a pump received and supported in the casing; a gap between the casing and the pump to allow fluid to enter the casing; a first filter located equal to or below the top of the casing and extending across the gap between the inner wall of the casing and the pump; and a second filter located below the first filter and extending between the inner wall of the casing and the pump; whereby the fluid enters the sump assembly through the gap and passes successively through the first and second filters into the lower regions of the casing, before being discharged from the casing by the pump.

2. A sump assembly according to claim 1 wherein the cavity is equal or greater in size than the outer dimensions of the casing.

3. A sump assembly according to claims 1 or 2 wherein the top of the casing is level with the floor surface.

4. A sump assembly according to claims 1, 2 or 3 wherein the casing is secured to the floor structure. A sump assembly according to any one of the preceding claims wherein the casing has a securing means extending radially outward from the top of the casing for securing the sump assembly to the floor structure.

WO 02/097204 PCT/AU02/00685 -14-

6. A sump assembly according to any one of the preceding claims wherein the casing has a lower section frusto-conical in shape.

7. A sump assembly according to claim 6 wherein the lower section has an end wall providing a bottom for the casing.

8. A sump assembly according to any one of the preceding claims wherein the first filter is below the top of the casing allowing any spilt fluid to be received therein.

9. A sump assembly according to any one of the preceding claims wherein the first filter is removable from the sump assembly to allow cleaning.

10. A sump assembly according to any one of the preceding claims wherein the first filter comprises a body and a handle for removal purposes, wherein the body comprises a bottom, four sides and an open top to define a filter chamber.

11. A sump assembly according to claim 10 wherein the bottom and sides have staggered apertures for trapping solids and preventing them passing through.

12. A sump assembly according to any one of the preceding claims wherein the second filter is fixedly connected to the casing, extending between the inner wall of the casing and the pump.

13. A sump assembly according to any one of the preceding claims wherein the second filter comprises punched plate having a plurality of staggered apertures.

14. A sump assembly according to claims 11, 12 or 13 wherein the apertures are slots having round ends.

15. A sump assembly according to claim 14 wherein the slots are sufficient in size to prevent solids, which are too large for the pump, passing through. WO 02/097204 PCT/AU02/00685

16. A sump assembly according to claims 14 or 15 wherein the slots are configured so as to minimise oversized particles becoming jammed in the filters which may prevent spilt fluids entering the casing.

17. A sump assembly according to any one of claims 13 to 16 wherein the apertures of the second filter are smaller than the apertures in the first filter.

18. A sump assembly according to any one of the preceding claims wherein the pump is removably received in the casing.

19. A sump assembly according to any one of the preceding claims wherein a support means supports the pump in the casing.

20. A sump assembly according to any one of the preceding claims wherein the pump comprises a first and second intake.

21. A sump assembly according to claim 20 wherein the first intake is located below the second intake.

22. A sump assembly according to claims 20 or 21 wherein the first and second intakes each comprise an opening having a screen located over each opening to filter and control the size of the solids entering the pump.

23. A sump assembly according to any one of the preceding claims wherein the pump has a control means to operate the pump at predetermined fluid levels.

24. A sump assembly according to any one of claims 10 to 23 wherein the uppermost fluid level is above the bottom of the first filter. A sump assembly according to any one of claims 6 to 24 wherein the pumping assembly has an agitation means for agitation of the fluid in the lower section of the casing.

WO 02/097204 PCT/AU02/00685 -16-

26. A sump assembly according to claim 25 wherein the agitation means comprises a plurality of nozzles supplied with high-pressure water.

27. A sump assembly according to claim 26 wherein at least one of the nozzles is adapted to direct water to the first intake to remove any accumulated material, and at least one further nozzle is directed to the inner surface of the casing.

28. A sump assembly according to claim 25 wherein the agitation means comprises four nozzles, wherein one nozzle is directed to the first intake and the remaining three nozzles are directed to the inner surface of the casing.

29. A sump assembly according to claims 26, 27 or 28 wherein the agitation means has an activation means which activates and deactivates the nozzles at predetermined fluid levels.

A sump assembly according to any one of the preceding claims wherein the sump assembly also comprises a sensing means to sense the fluid levels in the casing.

31. A sump assembly according to claim 30 wherein the sensing means comprises a plurality of sensing probes.

32. A sump assembly according to claim 31 wherein the sensing probes are enclosed by a housing.

33. A sump assembly according to claim 32 wherein the housing protects the probes from excessive wear due to abrasion by the fluid whilst allowing slight movement of the fluid around the probes to prevent accumulation of the material.

34. A sump assembly according to claim 31, 32 or 33 wherein the sensing probes send signals to activate and deactivate the various components of the sump assembly in accordance with different fluid levels during operation.

WO 02/097204 PCT/AU02/00685 17- A sump assembly according to any one of the preceding claims wherein the inner surface of the casing is lined with wear resistant material.

36. A sump assembly as substantially herein described with reference to the drawings.