WO2004073832A1

WO2004073832A1 - Filtration vessel

Info

Publication number: WO2004073832A1
Application number: PCT/GB2004/000557
Authority: WO
Inventors: James C. Beveridge
Original assignee: Symons Ltd
Priority date: 2003-02-20
Filing date: 2004-02-13
Publication date: 2004-09-02

Abstract

A filtration vessel (1) including a distribution header (2) for supplying fluid to be filtered to a stack (10) of filtration canisters (7). A moving means (6) is provided to move the distribution header (2) between an upper and a lower position to assist with the adding, removal and/or replacement of the canisters (7).

Description

FILTRATION VESSEL

The present invention relates to a filter system, and in particular to a filter system comprising a vessel containing a plurality of filtration canisters.

In conventional filter systems of this general type, a vessel is provided including guide rods extending throughout the vessel which support individual filter canisters, Typically over one hundred canisters are provided in such a vessel. The vessel includes a fluid inlet at one end, typically from the side, through which fluid to be filtered is introduced. The fluid flows radially from the outside of the canisters to the inside. The fluid is then discharged through the canisters and through the opposite end of the vessel to that through which the fluid is introduced.

Over time, the filter material within the canisters will become spent, and the canisters will need replacement. To achieve this, the canisters must be removed individually from the vessel, lifting each canister from and over the guide rod on which it is mounted. Typically, the canisters of spent media may weigh up to about 30 kilograms, and accordingly are difficult to manhandle. Further, due to the large number of canisters provided within the vessel, often in close proximity to each other, and especially when the canisters to be removed are towards the bottom of the vessel, such removal may be difficult. This is especially the case as, for the lower canisters, it is often not possible to see these. Furthermore, the canisters when removed are dirty, the material removed from the fluid by the filtration is present on the outside of the filter canisters since the fluid flows from the outside to the inside of the canisters.

It will be appreciated that the filtration system to which the present invention relates may include an absorption filtration system, in which the canisters include an absorption medium for absorption of material passing through them, or any other form of filtration, for example for the removal of suspended material by passing fluid through pores in a filter medium. All references to filter, filter medium and filtration should be understood to cover all such mechanisms.

According to the present invention, a filter vessel system comprises:

a filter vessel;

a distribution header provided within the vessel, and movable between an upper position and a lower position;

a means for moving the distribution header between the upper and lower position; and,

a plurality of filter canisters connected to the distribution header, and stacked to define at least one filter stack, the filter canisters being arranged such that fluid to be filtered passes through the distribution header and through the filter stacks to filter the fluid.

With the arrangement according to the present invention, the distribution header can be raised and lowered within the vessel. Therefore, when the filter canisters are to be removed, it is possible to raise the distribution header so the next layer of filter canisters can be moved towards the top of the vessel, and can be accessed easily for removal. As each layer of canisters is removed, the distribution header can be raised to bring the next layer to the top of the vessel. When inserting new canisters to form the filter stacks, the process can be reversed. In this way, access to the filter canisters for removal and replacement of these is greatly simplified. Further, as all the filter canisters to be added or removed can be positioned at the top of the vessel, automated loading and/or removal machines may be used for removing and replacing the canisters.

Advantageously, the filter canisters are provided on guide rods. It is preferred that the guide rods are removable. This avoids each filter canister needing to be passed over the top of an elongate guide rod for removal and replacement. Preferably the guide rods are formed from sections, allowing a section to be added or removed as necessary. This avoids the need to remove an entire guide rod leaving the stack of canisters unsupported.

The distribution header is preferably in the form of an internal pressure vessel. In any case, the distribution header should include multiple locations for canisters, allowing the vessel to provide multiple filter stacks.

The moving means for moving the distribution header between the upper and lower positions may be in the form of a hydraulic or electric actuator, a manual or automated hoist, or other suitable lifting means. Advantageously, the moving means is associated with a locking or latching mechanism to retain the distribution header at a particular position within the vessel. This is advantageous as it ensures that in the event that the moving means fails, the distribution header is retained in position, and does not drop within the vessel. Advantageously the locking or latch mechanism comprises a T slot, in which a projection from the lifting means or distribution header is received in a slot within the vessel.

Each of the filter canisters are provided so that fluid flows between the ends of the canister for filtration. Preferably, the top and bottom of the canisters include a radial slot arrangement to promote distribution of the fluid throughout the media contained within the canister.

To assist formation of the filter stacks, the canisters are preferably arranged to mate or interlock with each other. Such interlocking may comprise a resilient clip for snap fitting between the canisters. The connection between the canisters preferably includes a seal to ensure fluid does not flow laterally out of the stack between each canister. It is advantageous that part of the casing of the canister is removable to allow removal and replacement of the media. In one embodiment, either the top or bottom, or both, of the canister is removable to allow removal and replacement of the media. In this case, the top or bottom may snap fit onto the body of the canister.

In a preferred embodiment, the filter media comprises an absorption media.

Especially where the canisters are intended to be removed by automated machines, it is preferred that the canister includes suitable projections or recesses that may be engaged by the lifting machinery.

According to a second embodiment of the present invention, a method of removing and replacing filter canisters within a vessel according to the first embodiment of the present invention comprises removing the upper canisters from filter stacks within a vessel, raising the distribution header to bring the next row of canisters to the top of the vessel and removing these canisters, and repeating these steps until all canisters have been removed, providing a new layer of canisters on the distribution header, lowering the distribution header so that the canisters are below the top of the vessel, providing a new layer of canisters on top of those provided, and repeating these steps until the desired filter stacks have been formed.

With the method according to this embodiment of the invention, it is relatively easy to remove and replace filter canisters at the top of the vessel, without having to reach to the bottom of the vessel to remove these.

Preferably, prior to removal of the filter canisters, guide rods on which the filter canisters are provided are removed from the vessel. This avoids the need to lift the filter canisters over the end of the guide rods. In this case, the guide rods are preferably reintroduced after the new filter stacks have been formed. The present invention will be described by way of example with reference to the accompanying drawings in which:

Figure 1 shows a cross sectional view (taken through the line A-A of Figure 3) of the filter vessel with the distribution header in a raised position;

Figure 2 shows a cross section similar to that of Figure 1 with the distribution header in a lower position, and including filter stacks;

Figure 3 shows a plan view of the vessel with the top removed of Figure 2;

Figure 4 shows a stack of two filter canisters;

Figure 5 shows a plan view of a filter canister;

Figure 6 shows a side view of a snap seal; and,

Figure 7 shows a plan view of a snap seal.

As shown in Figure 1 , there is provided a filter vessel 1 including a distribution header 2. The distribution header 2 is in the form of an internal pressure vessel which includes a plurality of locations 3 for canister absorption filter stacks as described below. The distribution header 2 is connected to a fluid inlet 5 by a swivel jointed pipe system 4. As shown in Figure 1 , the swivel jointed pipe system is able to extend by opening the joint between the pipe sections as the distribution header raises. When the distribution header is lowered, the pipes swivel about the joints, as shown in Figure 2.

A hydraulic actuator 6 is used to raise and lower the distribution header 2 within the vessel 1. As can be seen from the plan view of Figure 3, three hydraulic actuators are provided, equally spaced around the external perimeter of the vessel. As an alternative to a hydraulic actuator, an electric actuator or manual or automated hoist may be used. To prevent the distribution header falling to the bottom of the vessel in the event that the hydraulic or other actuators 6 fail, the distribution header is preferably provided with a projection 8 which is received in a slot 9 on the inside of the vessel. The slot includes a hole, notches or the like that can receive the projection extending from the distribution header to hold the distribution header at any given height. In this way, in the event that the actuators 6 fail, the distribution header is retained at a particular height. Other or alternative mechanisms for locking the distribution header at a particular height within the vessel may be provided.

In the embodiment shown in Figure 1, a single filter canister 7 is provided on the distribution header. In use, filter canisters 7 will be provided on each of the multiple locations of the distribution header as shown in Figures 2 and 3. A plurality of the canisters are built up on each location, forming filter stacks 10. To form the filter stacks, a single filter canister is first provided on each of the multiple locations of the distribution header 2. The hydraulic actuators 6 are then actuated to lower the distribution header 2, approximately by an amount corresponding to the height of each filter canister 7. Then, a further layer of filter canisters 7 are provided on each of the multiple locations. The actuators 6 are then actuated to lower the distribution header further, allowing a further layer of canisters to be positioned on the existing stacks. The process is repeated until the desired number of layers of canisters 7 have been formed.

As can be seen from the embodiment in Figure 4, a snap type seal 20 is provided to seal adjacent canisters 7 in each stack. The seal is arranged to snap onto the top of one canister and the bottom of the overlying canister and may include O-rings 21 or the like to ensure a seal. This ensures that fluid flowing through the canisters 7 is not able to escape at the joint between two adjacent canisters. The snap type seal 20 is shown in greater detail in Figures 6 and 7. As can be seen in Figure 7, the seal includes a number of radial ribs supporting the seal. These ribs act to assist flow through the canister, whilst supporting the outer annulus of the seal 20. As can be seen in Figure 5, the canisters may have a similar top and bottom structure, with radial ribs supporting the outer circumference of the canister. This helps ensure reliable flow of fluid vertically through the canisters.

As shown in Figure 4, modular guide rods can be provided for supporting the stack of filter canisters 7. These guide rods 30 are connected to each other as each layer of canisters is formed. Alternatively, a single guide rod may be provided for each stack of canisters, and this can be added after all canisters in the stack have been formed.

When the filter stacks 10 have been formed, and the distribution header 2 is at its lowest position, the vessel can be sealed. Fluid is then supplied to the distribution header 2 via the inlet 5 and swivel jointed pipe system 4, and the fluid will flow vertically through the filter stacks 10. The clean fluid is discharged through the top of the stacks 10, through a suitable outlet.

During use, the media contained within the filter canister 7 will become spent. Eventually, it will be necessary to replace the filter canister 7. This can be achieved by removal of the seal of the vessel, and then removal of the first layer of filter canisters 7 from the filter stacks. After removal of the first layer of canisters 7, the hydraulic or other actuators 6, are actuated to raise the distribution header 2, bringing the next layer of filter canisters 7 to the top level of the vessel, allowing these to be removed easily. The process is repeated until all filter canisters 7 are removed, and then the stacks 10 can be reformed according to the method disclosed earlier. The filter media, which may be an absorption media, may be removed from the canister 7 and new media added.

In the case where a single guide rod is provided throughout all the filter canisters 7 in the filter stacks 10, the guide rod is removed before any of the filter canisters 7 are removed. However, in the case where modular guide rods 30 are provided, these can be removed with each layer of filter canisters 7.

Although not shown, the individual filter canisters may include suitable projections, recesses or other formations for assisting their removal by suitable removal machinery.

Claims

1. A filter vessel system comprising:

a filter vessel (1);

a distribution header (2) provided within the vessel, and movable between an upper position and a lower position;

a means (6) for moving the distribution header (2) between the upper and lower position; and,

a plurality of filter canisters (7) connected to the distribution header (6), and stacked to define at least one filter stack (10), the filter canisters (7) being arranged such that fluid to be filtered passes through the distribution header (2) and through the filter stacks (10) to filter the fluid.

2. A filter vessel system according to Claim 1 , in which the filter canisters (7) are provided on guide rods (30).

3. A filter vessel system according to Claim 2, in which the guide rods (30) are removable.

4. A filter vessel system according to Claim 2 or Claim 3, in which the guide rods (30) are formed from sections, allowing a section to be added or removed as necessary.

5. A filter vessel system according to any one of the preceding claims, in which the distribution header (2) is in the form of an internal pressure vessel.

6. A filter vessel system according to any one of the preceding claims, in which the distribution header (2) includes multiple locations (3) for canisters (7), allowing the vessel to provide multiple filter stacks (10).

7. A filter vessel system according to any one of the preceding claims, in which the moving means for moving the distribution header (2) between the upper and lower positions is in the form of a hydraulic or electric actuator, a manual or automated hoist, or other suitable lifting means.

8. A filter vessel system according to any one of the preceding claims, in which the moving means is associated with a locking or latching mechanism (8, 9) to retain the distribution header (2) at a particular position within the vessel (1).

9. A filter vessel system according to any one of the preceding claims, in which the ends of the canisters (7) include a radial slot arrangement to promote distribution of the fluid throughout the media contained within the canister (7).

10. A filter vessel system according to any one of the preceding claims, in which the canisters (7) are arranged to mate or interlock with each other.

11. A filter vessel according to any one of the preceding claims, in which the canisters (7) include an absorption media.

12. A method of removing and replacing filter canisters within a vessel according to any one of the preceding claims comprises removing the upper canisters from filter stacks within a vessel, raising the distribution header to bring the next row of canisters to the top of the vessel and removing these canisters, and repeating these steps until all canisters have been removed, providing a new layer of canisters on the distribution header, lowering the distribution header so that the canisters are below the top of the vessel, providing a new layer of canisters on top of those provided, and repeating these steps until the desired filter stacks have been formed.