WO2001007140A1

WO2001007140A1 - Method of removing a filter medium from a filter vessel, and evacuating device for use in such method

Info

Publication number: WO2001007140A1
Application number: PCT/IB2000/001028
Authority: WO
Inventors: Christopher Peter Sharland
Original assignee: Christopher Peter Sharland
Priority date: 1999-07-26
Filing date: 2000-07-26
Publication date: 2001-02-01
Also published as: AU6174800A

Abstract

In filters of the type comprising a filter vessel (52) having a restricted access opening (58) providing access to the inside of the vessel, and a bed of particulate filter medium (54) in the vessel, the removal of filter medium from the vessel for purposes of cleaning or replacing the medium is normally a laborious and time-consuming operation. In accordance with the invention the filter medium is removed from such a vessel by inserting an evacuator tube (12) having a inlet opening (16) at one end thereof via the access opening into the vessel so that said one end penetrates into the bed of filter medium; fluidising the filter medium in the region of the inlet opening by means of a primary fluid jet (62); and evacuating the fluidised filter medium from the filter vessel via the evacuator tube, through suction created by means of a secondary fluid jet (66) disposed at or near the inlet opening and being directed into the evacuator tube.

Description

METHOD OF REMOVING A FILTER MEDIUM FROM A FILTER VESSEL. AND EVACUATING DEVICE FOR USE IN SUCH METHOD

This invention relates to a method of removing a particulate filter medium from a filter vessel containing such medium, and to an evacuating device for use in the method.

According to the invention there is provided, in a filter of the type comprising a filter vessel having a restricted access opening providing access to the inside of the vessel, and a bed of particulate filter medium in the vessel, a method of removing the filter medium from the vessel, which method comprises inserting an evacuator tube having a inlet opening at one end thereof into the vessel so that said one end penetrates into the bed of filter medium, fluidising the filter medium in the region of the inlet opening by means of one or more primary fluid jets, and evacuating the fluidised filter medium via the evacuator tube.

The fluidised filter medium may be evacuated through suction created by means of a secondary fluid jet at or near the inlet opening and directed into the evacuator tube.

The suction may be enhanced by one or more further secondary fluid jets inside the evacuator tube and directed downstream of the evacuator tube.

The primary and/or the secondary fluid jets may be pulsating jets, i.e. they may be turned off and on periodically.

Further according to the invention there is provided an evacuating device for use in removing a particulate filter medium from a filter vessel containing such medium, the device comprising an evacuator tube having an inlet end, a primary jet nozzle for establishing a primary fluid jet to fluidise the filter medium in the region of said inlet opening, and means defining a flow passage for supplying a fluid under pressure to the primary jet nozzle. The device may further comprise a secondary jet nozzle at or near said inlet opening, for establishing a secondary fluid jet directed into the evacuator tube through the inlet opening and thereby creating, by Venturi action (herein also referred to as "jet action"), suction in the evacuator tube which has the effect of propelling the fluidised medium up the evacuator tube.

The device may comprise one or more further secondary jet nozzles in the evacuator tube, the (or each) further secondary jet nozzles being directed downstream of the evacuator tube. The device may comprise an outer tube, the evacuator tube being concentric with and disposed inside the outer tube, the evacuator tube and the outer tube defining between them an annular space, and said annular space constituting said flow passage for fluid under pressure. The invention will now be described in more detail, by way of example, with reference to the accompanying drawings. In the drawings: Figure 1 is a side view of an evacuating device in accordance with a first embodiment of the invention; Figure 2 is a section on ll-ll in Figure 1 , drawn to a larger scale;

Figure 3 is a view in the direction of III in Figure 1 , also drawn to a larger scale;

Figure 4 diagrammatically illustrates the device of Figures 1 to 3, when in use to remove a particulate filter medium from a filter vessel;

Figure 5 is a side view of an evacuating device in accordance with a second embodiment of the invention;

Figure 6 is a detail longitudinal section of an upper part of the evacuating device of Figure 5;

Figure 7 is a detail longitudinal section of a central part of the evacuating device of Figure 5;

Figure 8 is a detail longitudinal section of a lower part of the evacuating device of Figure 5; and

Figure 9 is a section on IX-IX in Figure 7. Referring first to Figures 1 to 3, reference numeral 1 0 generally indicates an evacuating device for removing a particulate filter medium (e.g. sand) from a filter vessel containing such medium, the device comprising an evacuator tube 1 2 and, running parallel to the evacuator tube, a water supply tube 14. The lower end of the evacuator tube 1 2 is open, forming an inlet opening 1 6. The evacuator tube 1 2 has a straight vertical section 1 8 extending upwardly from the lower end thereof, a horizontal section 20, an elbow 22 forming a transition between the vertical and horizontal sections, and a terminal section 24 at the outlet end of the horizontal section. Whereas the sections 1 8, 22, and 24 are of an opaque material, the section 20 is of a transparent material, so as to enable the flow of material through the evacuator tube to be observed from the outside.

Mounted on the lower end of the evacuator tube 1 2 there is an L-shaped component 26. The water supply tube 14 is connected to the component 26 via an annular fitting 28. In the water supply tube 1 4, and mounted to the underside of the horizontal section 20, there is a valve 30, the valve having an operating lever 32. The upper end of the water supply tube 1 4 is provided with a connector 34 whereby the water supply tube can be connected to a water hose. In areas where the mains water supply pressure and flow rate is sufficiently high, the water hose may be connected direct to the mains water supply. Alternatively it may be connected to a water supply via a booster pump (not shown). Further alternatively, it may be connected to the pool pump by means of one or more adaptors fitted to the filter valve, or directly to the pool pump, to divert the water supply from the pool pump to the water supply tube 1 4.

The annular fitting 28 is provided with a number of circumferentially spaced, downwardly and radially outwardly directed primary jet nozzles 36 which are in flow communication with the inside of the water supply tube 1 4. Although three jet nozzles are shown in the drawings, it is to be understood that there can be any number of such nozzles. The horizontal limb of the L- shaped component 26 has a secondary jet nozzle 38 mounted thereon, the jet nozzle 38 being directed into the evacuator tube 1 2 via the inlet opening 1 6. The L-shaped component 26 has a flow passage therein, which places the inside of the water supply tube 1 4 in flow communication with the jet nozzle 38. The L-shaped component 26 further has, on the underside thereof, a horizontally directed primary jet nozzle 40, this also being in flow communication with the passage in the L-shaped component.

A further secondary jet nozzle 42 is provided, this being arranged inside the evacuator tube 1 2 and being directed upwardly, i.e. in the downstream direction of the evacuator tube. The jet nozzle 42 is in flow communication with the inside of the water supply tube 1 4 via a fitting 44. In Figure 1 the evacuator tube 1 2 is shown broken away in the region of the jet nozzle 42. This is for purposes of illustration only, to render the jet nozzle visible.

The manner in which the evacuating device 1 0 is used will now be described with reference to Figure 4, where reference numeral 50 indicates a conventional swimming pool filter of the type comprising a filter vessel 52 containing a bed of particulate filter medium in the form of sand 54. The vessel 52 has a base 56 and a restricted top opening 58. Reference numeral 60 indicates a conventional valve assembly which, during normal use, is mounted on the vessel so as to close the top opening 58. For effective operation of the filter 50, the sand 54 should be removed from the vessel 52 from time to time and replaced with new sand, or, alternatively, cleaned and then returned to the vessel. Because of the restricted size of top opening 58 it is difficult to remove the sand. By using the evacuating device 1 0 of the present invention, the sand can be removed rapidly, and with a minimum of effort. To do so, the water supply tube 14 is connected via the connecter 34 to a mains water supply, either direct or via a booster pump. The valve assembly 60 is removed so as to provide access to the inside of the vessel 52 via the top opening 58, and the end of the evacuating device 1 0 then inserted into the vessel through the top opening. With the water supply being turned on, the evacuating device is pushed down so that the end thereof penetrates into the sand 54. The water supply is turned on by operating the lever 32.

This is done as the end of the evacuating device is being inserted into the sand bed, water jets 62 issuing from the jet nozzles 36 and 40 assisting the evacuating device in penetrating into the sand bed. The water jets 62 are effective to fluidise the sand in the region of the inlet opening 1 6, as indicated by the dotted line 64.

The secondary jet nozzle 38 forms a water jet 66 which is directed into the evacuator tube 1 2 via the inlet opening 1 6, creating suction through jet action. A secondary jet 68 issues from the jet nozzle 42, this jet, through jet action, enhancing the suction created by the jet 66.

The suction created by the jets 66 and 68 causes the fluidised sand to be evacuated from the vessel 52 via the evacuator tube 1 2. The evacuated sand and the water in which it is entrained can be observed as it flows through the clear, horizontal section 20 of the evacuator tube. It has been found that the effectiveness of the device in evacuating the vessel 52 can be improved by turning the valve 30 off and on periodically. This causes a pulsating flow of water through the jet nozzles 36, 40, 38, and 42. The frequency at which the valve 30 is closed and opened can be varied by the operator according to the observed flow of sand and water through the evacuator tube, as observed through the transparent horizontal section 20 of the evacuator tube.

If desired, the terminal end of the evacuator tube 1 2 may be connected to a perforated bag, to enable the evacuated sand to be recovered. The recovered sand can then be cleaned and re- used if desired

If desired, a separate lance (not shown in the drawings) which produces a water jet may be used to assist in loosening and fluidising the sand in the filter vessel. The lance can be manipulated independently of the device 1 0. The filter shown in the drawings is of the type having a so-called top-mounted valve where the entire valve assembly must be removed to gain access to the inside of the filter vessel. There are also filters known as side-mounted units, where the valve assembly is attached through two holes in the side of the filter vessel as a permanent fixture. In this event access to the inside of the vessel is gained through an access port or lid which can be removed without disturbing the valve assembly. By tapping into the valve assembly, the water from the pool pump can be accessed. This is achieved by removing the top of the valve assembly which is held down by six screws, and by inserting a blank-off disc which will be supplied with each evacuating device. This enables the pool pump water to be diverted to the evacuating device, and good pressure and delivery volumes to be obtained without any special equipment or techniques. Turning now to Figures 5 to 9, reference numeral 1 0.1 generally indicates an evacuating device which in certain respects is similar to the device 1 0 of Figures 1 to 3, the same reference numerals being used to indicate the same or similar parts. The evacuating device 1 0.1 differs essentially from the evacuating device 1 0 in that the main body of the device comprises two concentrically arranged inner and outer tubes 70 and 72 respectively, the two tubes defining an annular space 74 between them. The inner tube 70 has the same function as the evacuator tube 1 2 of the device 1 0, whereas the annular space 74 serves the same purpose as the water supply tube 1 4 of the device 1 0.

As can best be seen in Figure 6, the device 1 0.1 has, at the upper end thereof, an elbow 76 and a T-connector 78. The horizontal section 20 is connected to one end of the elbow 76, whereas the other end of the elbow is connected to one end of the T-connector 78. The other end of the T-connector 78 is connected to the outer tube 72, whereas the valve 30 is connected to the side port of the T-connector 78. At the junction between the elbow 76 and the T-connector 78 there is an annular fitting 80 which serves to block off or close the annular space 74 at the upper end of the device. The side port of the T-connector 78 is in flow communication with the annular space 74.

As can best be seen in Figure 7, the secondary jet nozzle 42 is fitted to the inside of the inner tube 70, a hole being cut in the inner tube 70 so as to place the annular space 74 in flow communication with the jet nozzle 42. As can best be seen in Figure 8, the annular space 74 is blocked off or closed by means of an annular element 82 at the lower end of the device 1 0.1 .

The lower end of the device 1 0.1 is provided with a component 84, the secondary jet nozzle 38 being formed in this component. The component 84 is secured to the inside of the inner tube 70, and passages are cut in the component and in the inner tube 70, above the element 82, thereby to place the secondary jet nozzle 38 in flow communication with the annular space 74.

Near the lower end of the device 1 0.1 a number of peripherally spaced, inclined openings are drilled in the outer tube 72, to form a series of periphery spaced primary jet nozzles 86. These nozzles perform the same function as the primary jet nozzles 36 in the device 10.

Set back from the nozzles 86 there is an external collar 88 on the outside of the outer tube 72. This forms an end stop for an optional, removable extension foot 90 (indicated in dotted lines), which is a tight sliding fit on the outside of the outer tube 72. The extension foot has notches 92 in the leading edge thereof and is useful in regions where the filter medium is otherwise difficult to dislodge and remove.

Claims

CLAIMS:

1 . In a filter of the type comprising a filter vessel (52) having a restricted access opening (58) providing access to the inside of the vessel, and a bed of particulate filter medium (54) in the vessel, a method of removing the filter medium from the vessel, which method is characterised in that: an evacuator tube ( 1 2) having a inlet opening ( 1 6) at one end thereof is inserted via said access opening into the vessel so that said one end penetrates into the bed of filter medium; the filter medium in the region of the inlet opening is fluidised by means of a primary fluid jet (62); and the fluidised filter medium (64) is evacuated from the filter vessel via the evacuator tube.

2. A method as claimed in claim 1 , characterised in that the fluidised filter medium (54) is evacuated through suction created by means of a secondary fluid jet (66) which is disposed at or near the inlet opening ( 1 6) and is directed into the evacuator tube ( 1 2) .

3. A method as claimed in claim 2, characterised in that the suction created by means of said secondary fluid jet (66) is enhanced by one or more further secondary fluid jets (68), the further secondary fluid jet or jets being disposed in the evacuator tube ( 1 2) and being directed downstream of the evacuator tube.

4. A method as claimed in claim 2 or claim 3, characterised in that the (or each) secondary fluid jet (68) is caused to pulsate.

5. A method as claimed in claim 4, characterised in that the (or each) secondary fluid jet (68) is turned off and on periodically.

6. A method as claimed in any one of the preceding claims, characterised in that the primary fluid jet (62) is caused to pulsate.

7. A method as claimed in claim 6, characterised in that the primary fluid jet (62) is turned off and on periodically.

8. An evacuating device for use in removing a particulate filter medium (54) from a filter vessel (52) containing such medium, characterised in that it comprises an evacuator tube ( 1 2) having an inlet end ( 1 6), a primary jet nozzle (36, 40) for establishing a primary fluid jet (62) to fluidise the filter medium in the region of said inlet opening, and means ( 1 4) defining a flow passage for supplying a fluid under pressure to the primary jet nozzle.

9. An evacuating device as claimed in claim 8, characterised in that it further comprises a secondary jet nozzle (38) at or near said inlet opening, for establishing a secondary fluid jet directed into the evacuator tube ( 1 2) through the inlet opening ( 1 6) and thereby creating, by jet action, suction in the evacuator tube which has the effect of propelling the fluidised medium (54) up the evacuator tube.

1 0. An evacuating device as claimed in claim 9, characterised in that it comprises one or more further secondary jet nozzles (42) in the evacuator tube, the (or each) further secondary jet nozzles being directed downstream of the evacuator tube.

1 1 . An evacuating device as claimed in any one of claims 8 to 1 0, characterised in that it comprises an outer tube (72), the evacuator tube (70) being concentric with and disposed inside the outer tube, the evacuator tube and the outer tube defining between them an annular space (74), and said annular space constituting said flow passage for fluid under pressure.

1 2. A method of removing the filter medium from a filter vessel, substantially as herein described and illustrated.

1 3. An evacuating for removing the filter medium from a filter vessel, substantially as herein described and illustrated.