GB2163060A - Sludge aeration apparatus - Google Patents

Abstract

A venturi sludge aerator has a motor (19) which pumps sludge from an input (30) through a venturi nozzle in a throat (13). Air is sucked in at the venturi through an air inlet (23) connected at a seal (A) to a fixed pipe (15). The aerator is mounted on a guide rail (4) and can be lifted out of the sludge tank by means of a crane. The guide rail incorporates an air pipe (5) connected to the pipe (15) feeding the venturi and drawing air from the top of the tank. The weight of the aerator holds the air inlet (23) in sealing connection with the pipe (15) at the seal (A) without any fasteners. The seal (A) is separated when the aerator is lifted out of the tank by the crane, and is automatically joined again when the aerator is lowered back into position. <IMAGE>

Description

SPECIFICATION Sludge Aeration Apparatus This invention relates to apparatus for aerating sludge.

Known venturi aeration apparatus include an aerator comprising a venturi nozzle through which sludge is pumped at or above atmospheric pressure into a receiving throat. The chamber connecting the nozzle and throat is open to atmospheric air or to a source of blown air. The jet of sludge from the nozzle is mixed with air and emitted from the throat.

In this way sludge can be aerated. The aerator is located, in use on the base of a sludge tank and is connected by flexible hoses to an air supply before activation of the sludge pump. Stirring and mixing of the mass of sludge in the tank is produced by the momentum of the pumped sludge and emerging air bubbles.

While maintenance of the aerator is required it must be hauled out of the tank. Since the flexible hoses are difficult to manouver over the tank wall sludge has a tendency to be dispersed in the vicinity of the tank during maintenance.

The present invention provides sludge aeration apparatus comprising a venturi sludge aerator and a rigid guide rail for guiding the aerator into its operating position in a tank, the guide rail including a rigid air supply line having a connection point arranged to mate with an air inlet of the aerator as the aerator approaches or assumes its operating position.

In this way it possible to separate the aerator from its air supply thus, eliminating the need for flexible air hoses so that maintenance of the aerator when used in a sludge tank is simpler and cleaner. The air supply connection point is provided in a manner which allows mating with the aerator air inlet as the aerator is guided to its operating position by the guide rail, thus simplifying connection of the aerator to its air supply.

In a preferred embodiment the air supply line is integral with the guide rail and the connection point is at or immediately adjacent to said operating position. Conveniently, the connection point comprises either a male or female connector and the air inlet comprises either a female or male connector respectively. In addition the guide rail can include means capable of moving the aerator into and out of its operating position, for example said means can comprise crane apparatus having its lifting cable attached to the aerator.

Examples of the present invention will now be described with reference to the accompanying drawings, in which:~ Figure 1 illustrates a sludge aeration apparatus embodying the invention.

Figure 2 illustrates a section through the connection point and air inlet contained within circle A of Figure 1.

Figure 3 illustrates a view along arrows A shown in Figure 1.

A sludge aeration system is illustrated in Figure 1 in use in a sludge tank 1. The apparatus comprises a guide rail 4 attached to a wall of the tank by means of bolts inserted into the wall through a connection point 3 and base plate 17 provided on the guide rail.

The guide rail is shaped to extend from the base of the tank vertically up the tank wall and over the edge of the tank as illustrated. Clearly other shaped guide rails could be employed. The vertical section of the guide rail extends to a crane apparatus 9.

The crane apparatus includes an outer pulley 10 over which a cable 11 runs to an object to be lifted.

The cable extends from pulley 10 over a further pulley 8 to a wind on pulley7 provided with a winding on handle 6. By rotation of the handle Sit is possible to wind on the cable thereby allowing an object to be lifted. Clearly manually operated or mechanically operated cranes can be used.

A sludge aerator comprises an elongate throat 13 connected to a sludge input section 18 which contains a motor 19. The motor 19, when activated through electric cable (not shown), pumps sludge from an input 30 through a venturi nozzle (not shown) into the throat 13. Air for aeration of the sludge is blown into the side of the throat through an air inlet pipe 23. In this way the sludge pump through sludge input section 18 is aerated before emerging from the end 14 of the elongate throat.

The air need not be blown into pipe 23, this pipe can instead be simply opened to atmospheric air. The aerated sludge emerging from end 14 is typically at above atmospheric pressure.

The sludge input section is connected to a slide means 20 which is provided around the guide rail 4.

The slide means is adapted to allow sliding movement up and down the guide rail and can either prohibit or allow rotation of the aerator about the axis of the guide rail. For example, the slide means can comprise a ring provided around the guide rail. Alternatively, as can be seen from Figure 3, the slide means 20 does not form a ring extending completely around the guide rail 4 but is slotted to allow passage of the slide means past an air pipe 5 opening into the interior of the guide rail 4. In this way the aerator can be slid up and down the rail.

The movement is achieved by connecting the crane cable 11 to a ring 12 provided on the throat. By rotation of the crane handle 6 the aerator can be lifted for inspection, maintenance and servicing.

When the aerator is lowered to its operating position of sludge aeration, a roller 22 provided on slide means 20 engages a guide 2 connected to the side wall of the tank 1. The roller bears against a surface 21 of the guide 2 which urges the aerator into its operating position, in which position the air inlet pipe mates with an air supply connecting pipe 15. The air supply pipe is connected to the guide rail by a further pipe 33 and support member 34 in a manner to tolerate forceful engagement of the pipe 15 with pipe 23. Preferably a support plate 16 is fixed to the pipe 15 and shaped and positioned to support the throat 13 when the aerator is in it is operating position.

By providing a hollow guide rail and pipe 33 air can be blown in at an entrance 5 to the guide rail to supply the required air to air inlet pipe 23. Therefore there is no requirement for flexible hoses between an air blower close to the tank and the air inlet pipe 23. It will be apparent that the pipe 15 could alternatively be connected to a rigid air supply line provided parallel to the guide rail and linking to an air blower close to the tank. It will be apparent that inlet pipe 23 could be extended vertically and provided with an inlet which mates with a rigid air supply connecting pipe extending from the tank wall.

The form of connection point on the end of the pipe 15 to which the air inlet pipe mates is illustrated in Figure 2. The air inlet pipe is shown as having a flange 24 welded on to the inlet end of pipe 23, which flange has a raised lip 27 on its inner edge and accommodated an O-ring mid-way between its inner and outer edges. Similarly a flange 25 is welded on to the end of pipe 15, which flange includes a recess 26 on its operating position they mate together and the O-ring 28 provides a seal between the faces of the flanges 24 and 25. It is not essential that this seal is water-tight. Any suitable form of compatible male and female type mating ends can be provided on the end of pipe 15 and the air inlet 23.

The above described sludge aeration apparatus has been found to be of particular use when employed with anaerobically digested sludge. The period for settling of such sludge has been found to be considerably shortened if itis given a twelve hour aeration treatment with the apparatus. By using the above apparatus, the aerator can be removed easily from the sludge without the inconvenience and difficulty associated with sludge apparatus have flexible air supply hoses.

Furthermore, once word has been completed on the aerator it can be lowered to its operating position, wherein the air supply connections to it are automatically made.

Claims (7)

1. Sludge aeration apparatus comprising a venturi sludge aerator and rigid guide rail for guiding the aerator into its operating position in a tank, the guide rail including a rigid air supply line having a connection point arranged to mate with an air inlet of the aerator as the aerator approaches or assumes its operating position.

2. Sludge aeration apparatus as claimed in Claim 1, wherein the air supply line is integral with the guide rail.

3. Sludge aeration apparatus as claimed in Claim 1 or 2, wherein the connection is at or immediately adjacent said operating position.

4. Sludge aeration apparatus as claimed in any preceding claim, wherein the connection point comprises either a male or female connector and the air inlet comprises either a female or male connector, respectively.

5. Sludge aeration apparatus as claimed in any preceding claim, wherein the guide rail includes means capable of moving the aerator into and out of its operating position.

6. Sludge aeration apparatus as claimed in Claim 5, wherein said means comprises crane apparatus having its lifting cable capable of being attached to the aerator.

7. Sludge aeration apparatus substantially as herein described with reference to the accompanying drawings.