GB2226507A

GB2226507A - Scraper in settling tank

Info

Publication number: GB2226507A
Application number: GB8927401A
Authority: GB
Inventors: Eric Samuel Davidson; James Samuel Mclean
Original assignee: Interlink Equipment Ltd
Current assignee: Interlink Equipment Ltd
Priority date: 1988-12-02
Filing date: 1989-12-04
Publication date: 1990-07-04
Anticipated expiration: 2009-12-04
Also published as: GB2226507B; GB8927401D0; GB8828262D0

Abstract

A rectangular settling tank has a sump at one end into which settled solids are moved by a scraper 16 extending across the tank astride a rail 20. The rail 20 is reciprocated lengthwise by means 26-34 and carries teeth 22 which engage a ratchet on the scraper, so that the scraper is moved stepwise along the tank pushing the solids in front. When the scraper reaches one end of the tank, means on the rail reverses the ratchet action so that subsequent reciprocations of the rail move the scraper back. During the return movement, the scraper blades hinge upwards to ride over the settled solids. The scraper has a central floor-engaging blade and end blades 16B engaging the tank sides. The tank may be divided, each section having its own scraper. <IMAGE>

Description

SWAP33 APPARATUS.

This invention relates to scraper apparatus for periodic cleaning of sediment/slu#ge from the bottom surface of a tank or reservoir (hereinafter in the specification and claims referred to simply as a 'tank") while the tank is full, or substantially so, of liquid.

Accordingly, a first aspect of the present invention is scrager.apparatus for a rectangular bottomed tank comprising a scraper assembly formed from an elongate scraper carried on a housing, the housing adapted to track a rail to extend lengthwise of the bottom of the tank with the scraper transverse of the tank, the rail having a series of upstanding catches eiui-spaced apart longitudinally thereof and engageable one at a time with a ratchet mechanism in said housing, said rail being shorter than the lenyth of the tank and being constrained on the bottom of the tank for reciprocal lengthwise movement only, and means to reciprocate the rail to cause the assembly to be progressively moved from one end of the tank towards the other end and back again by the ratchet mechanism engaging each sequential catch on each outward movement of the rail while allowing free return movement of the rail.

Further accordingly, a second aspect of the present invention is a rectangular bottomed tank having a scraper apparatus fitted thereto, the scraper apparatus comptlsing a scraper assembly formed from an elongate scraper carried on a housing, the housing tracking a rail fitted to extend lengthwise of the tank with the scraper transverse of the tank, the rail having a series of upstanding catches euui-spaced apart longitudinally thereof and engageable one at a time by a ratchet mechanism in said housing, said rail being shorter than t@e length of the tank and constrained on the bottom c the tank for reciprocal lengthwise movement only, and means to reciprocate the rail to cause the assembly to be progressively moved from one end of the tams towards the other end and back again by the ratchet mechanism engaging each sequential catch on each outward movement of the rail while allowing free return movement of the rail.

Preferablz, means are provided on the rail at each end thereof to reverse the operation of the ratchet mechanism to allow the assembly on further reciprocation of the rail to Se progressed at intervals in a return movement.

Preferably also, the means for reciprocating comprises an upright lever connected at its bottom end to the rail and at its top end to the distal end of a piston or cslinfer of a piston and cylinder arrangement, the lever being pivoted mid-length, or substantially so, to operate as a simple lever with an outward stroke of the piston or cylinder of the arrangement causing a substantially similar movement of the rail.

Preferably further, for a tank of large areal dimensions, the bottom of the tank is compartrnented into a series of similar side-by-side passages, each having a scraper apparatus fitted to operate therein.

The scraper for the or each apparatus preferably includes a two part central portion, one part on each lateral side of the housing, the central portion being flanked on each side by an outer wing portion inclined forwardly in the direction of outward scraping movement with the outer side of the wings in abutiaent, or nearly so, with the corresponding side of its passage.

An embodiment of the present invention will now be described, by was of example, with reference to the accompanying schematic drawings, in which: Fig. 1 is a plan view of a tank according to the present invention showing the tank compartmented into two passages each having a scraper apparatus fitted therein; and Fig. 2 is a vertical cross-sectional view of one end of the tank to a larger scale.

Referring to the drawings, a rectangular bottomed tank 10 is provided. The tank 10 is formed in the ground with a horizontal bottom 8 and four upstanSiny side walls 6. The bottom 3 of the tank 13 is compartmented by wall 24 into a series of two similar side-by-side passages 12. Each passage 12 has a scraper apparatus 14 fitted to operate therein from one end towards the other end and back again. The bottom 8 has a transverse channel 4 at the other end to receive sediment/sludge fed into it by the scraper apparatus.

Each scraper#apparatus 14 comprises a scraper assembly formed from an elongate scraper 16 carried on a housing 18. The housing 18 tracks a rail 23 fitted to extend lengthwise of the tank 10 with the scraper 16 transverse of the tank 10 as shown. The scraper 15 for each apparatus includes a two part central blade portion 16A, one part on each lateral side of the housing 18.

The central blade portion is flanked on each side by an outer wing blade portion 163 pivoted vertically thereto to be inclined forwardly in the direction of outward scraping movement towards the other end of the tank 13 with the outer side of the wing portions 163 in abutment, or nearly so, with the corresponding side of its passage 12, the wing blade portions 163 folding into a substantially normal position to the central portion and trailing therefrom on a return movement. The central portion 16 has a framework (not shown) secured to the housing with uprights of the framework being rooted to skids (not shown) to slide across the bottom s of the tank 13.Within the framework, two blades (not shown), one in each part, are hinged along their top edge to the frasaework and are provided with a series of arcuate runners (not shown) such that on forward movement, the blades move into a vertical position for scraping but on a return movement the blades hinge upwardly in a trailing position due to the action of the arcuate runners.

The rail 20 has a series of upstanding catches 22 equi-spaced apart longitudinally thereof and engageable one at a time with a ratchet mechanism (not shown) in said housing 13. The rail 20 is shorter (as shown) than the length of the tank 10 and constrained on the bottom of the tank 13 for reciprocal lengthwise movement only.

Means to reciprocate the rail 20 is provided to cause the assembly to be progressively moved from one end of the tank towards the other end and back again by the ratchet mechanism engaging each sequential catch 22 on each outward movement of the rail 20 while allowing free return movement of the rail 23. The means for reciprocating comprises an upright lever 26 connected at its bottom end to the rail 20 and at its top end to the distal end of a piston 28 of a piston and cylinder arrangement 30. The lever 26 is pivoted mid-length at 32, or substantially so, to a bracket 34 to operate as a simple lever with an outward and return stroke of the piston 28 causing a substantially similar movement backwards and forwards respectively of the rail 23.For example, the stroke may be eighteen inches and giving a movement of the housing on the rail 20 of fifteen inches ie. the distance selected between each two catches 22.

Means are provided on the rail 23 at each end to reverse the operation of the ratchet mechanism to allow the assembly on further reciprocation of the rail 23 to be progressed at intervals in a return movement to said one end. The ratchet mechanism is a pawl hinged to the housing 18 whose bottom edge engages.each catch and whose top end carries a fin having an arcuate edge. The reverse operation means are slots, one at each end, into which the bottom end of the pawl falls and due to movement of the rail and the action of the fin is reversed.

A power unit (not shown) is provided for each scraper apparatus to operate the piston and cylinder arrangement 30 and comprises an oil reservoir and oil pump driven by an electric motor. A control unit for the electric motors of both apparatus is provided and can be time controlled to switch on the apparatus when required, the apparatus switching themselves off after completing an outward and return movement.

The apparatus is installed in a tank 10 as described above and operates as above described with any sludge being cleared from the bottom 8 of the tank 13 into channel 4 from whence it is removed.

In a modification, only one passage 12 can be provided or more than two passages 12 depending upon the resuire.nent.

The apparatus can be used with tanks having a sloped bottom.

Variations and modifications can be made without departing from the scope of the invention as abovedescribed.

Claims

CLAIMS:

1. Scraper apparatus for a rectangular bottomed tank comprising a scraper assembly formed from an elongate scraper carried on a housing, the housing adapted to track a rail to extend lengthwise of the bottom of the tank with the scraper transverse of the tank, the rail having a series of upstanding catches e#ui-spaced apart longitudinally thereof and engagable one at a tiiae with a ratchet mechanism in said housing, said rail being shorter than the length of the tank and being constrained on the bottom of the tank for reciprocal lengthwise movement only, and means to reciprocate the rail to cause the assembly to be proyressively moved from one end of the tank towards the other end and back again by the ratchet mechanism engaging each sequential catch on each outward movement of the rail while allowing free return movement of the rail.

2. A rectangular bottomed tank having a scraper apparatus fitted thereto, the scraper apparatus comprising a scraper assembly formed from an elongate scraper carried on a housing, the housing tracking a rail fitted to extend lengthwise of the tan with the scraper transverse of the tank, the rail having a series of upstanding catches equi-spaced apart longitudinally thereof and engagable one at a titae by a ratchet mechanism in said housing, said rail being shorter than the length of the tank and constrained on the bottom of the tank for reciprocal lengthwise movement only, and means to reciprocate the rail to cause the assembly to be progressively moved from one end of the tank towards the other end and tack again by the ratchet mechanism engaging each sequential catch on each outward movement of the rail while allowing free return movement of the rail.

3. Apparatus as claimed in Claim 1 or 2, wherein means are provided on the rail at each end thereof to reverse the operation of the ratchet mechanism to allow the assembly on further reciprocation of the rail to be progressed at intervals in a return movement.

4. Apparatus as claimed in Claim 1, 2 or 3, wherein the means for reciprocating the rail comprises an upright lever connected at its bottom end to the rail and at its top end to the distal end of a piston or cylinder of a piston and cylinder arrangement, the lever being pivoted mid-length, or substantially so, to operate as a si##le lever with an outward or return stroke of the piston or cylinder of the arrangement causing a substantially similar backwards or forwards movement of the rail respectively.

5. Tank as claimed in Claim 2, wherein for a tank of large areal dimensions, the bottom of the tank is compartmented into a series of similar side-by-side passages, each having a scraper apparatus fitted to operate therein.

6. Apparatus as claimed in any one of Claims 1 to 5, wherein the scraper for the or each apparatus includes a two part central portion, one part on each lateral side of the housing.

7. Apparatus as claimed in Claim 6, wherein the central portion is flanked on each side by an outer wing portion inclined forwardly in the direction of outward scraping movement with the outer side of the wings in abutment, or nearly so, with the corresponding side of its passage, the wing blade portions folding into a substantially normal position to the central portion and trailing therefrom on a return movement.

8. Apparatus as claimed in Claim 7, wherein the outer wing portions are each vertically hinged to the central portion.

9. Apparatus as claimed in Claim 6, 7 or 3, wherein the central portion has a framework secured to the housing with uprights of the Eramewor.e being rooted to skids to slide across the bottom of the tank.

10. Apparatus as claimed in Claim 9, wherein within the framework, two blades, one in each part, are hinyed along their top edge to the framework and are provided with a series of arcuate runners such that on forward movement, the blades move into a vertical position for scraping but on a return movement the blades hinye upwardly in a trailing position due to the action OL the arcuate runners.

11. Scraper apparatus substantially as hereinbefore described with reference to the accompanying drawings.

12. A tank having one or more scraper apparatus fitted thereto substantially as hereinbefore described with reference to the accompanying drawings.