WO1994007583A1

WO1994007583A1 - Reciprocable scraper transporting device for moving floating sludge at settling basins and the similar at water purification plants

Info

Publication number: WO1994007583A1
Application number: PCT/SE1993/000773
Authority: WO
Inventors: Bertil Ljungberg
Original assignee: Zickert Products AB
Current assignee: Zickert Products AB
Priority date: 1992-10-01
Filing date: 1993-09-27
Publication date: 1994-04-14
Anticipated expiration: 1995-04-01
Also published as: AU5122893A; SE9202848D0

Abstract

The present invention relates to a reciprocable scraping transporting device for the movement of floating sludge at settling basins (1) and the similar at water purification plants, in particular sewage purification plants, whereby a traverse beam (6) being centrally placed over and in the longitudinal direction of the basin, whereby a sled (12) is movably arranged to the traverse beam (6) and whereby the sled (12) is provided with a hinged scraper blade (13) suspended in the sled (12) and whereby the sled (12) is arranged to be reciprocably moved step by step by means of a pushing shaft (11) being arranged in said traverse beam (6), the movement of said pushing shaft (11) being generated by a driving equipment (8) and whereby the scraper blade (13) is arranged to be present in the water surface (5) present in the basin (1).

Description

RECIPROCABLE SCRAPER TRANSPORTING DEVICE FOR MOVING FLOATING SLUDGE AT SETTLING BASINS AND THE SIMILAR AT WATER PURIFICATION PLANTS. DESCRIPTION Technical field

The present invention relates to a reciprocable scraper trans¬ porting device for the movement of floating sludge at settling basins and the similar at water purification plants.

The object of the present invention is to obtain a device hav¬ ing one or more scraping blades, having a low building height, manufactured in corrosion resistant materials, having few mov¬ able parts and being thereby simple and service amicable.

Background of the invention

Hitherto chain scrapers have been used in many settling basins to remove that sludge, which little by little flows to the wa¬ ter surface. These chain scrapers consists of one or more scraping blades which extend cross over the basin and which are towed forwardly by means of continuously working chains in a pater noster movement. These constructions have certain advan¬ tages by providing a good cleansing result and have in other respects a good functionality security as long as the const¬ ruction is intact. In spite of its solid basic construction, however, serious breakdowns often occur depending upon the tre¬ mendous corrosion which all components, including the chains are subject to as the environment in the settling basins of the purification plants is very corrosive due to the ingoing preci¬ pitation salts used in the chemical precipitation step of the purification plants, for the precipitation of inter alia phos¬ phorous, which salts of aluminium and iron are acidic. Chain scrapers, moreover requires a large distance between water sur¬ face and walking bridges which leads to high building costs. It has also been proposed a traverse crane which is operated above the water surface of the basin whereby an elevating scraper is mounted on arms on the traverse crane. A disadvantage using this construction is that it is complicated to use at present settling basins which are often provided with different types of equipment which provide a hindrance.

Thus there exists a desire for another type of scraper device for the transport of decantate and floating sludge in the ba¬ sins of the purification plants.

Description of the present invention

It has now surprisingly been shown possible to be able to solve the above-mentioned problem by means of a device of the present invention which is characterized by a traverse beam, centrical- ly placed over and in the longitudinal direction of said basin, whereby a sled is movably mounted to the traverse beam and whe¬ reby the sled is provided with a hinged scraping blade mounted to said sled, and whereby the sled is arranged to be fed reci¬ procably by means of a pushing axis arranged in said traverse beam, whereby its movement is generated by a driving device, such as a reductor motor having an excenter, a hydraulic cy¬ linder or the like, and whereby the scraper blade is arranged to be present in a water surface present in the basin.

By means of the present invention a scraping cycle can be pro¬ vided according to the following: A scraping cycle is started with lowering the scraping blade into the water surface in a first position, and then moving the same step by step forwardly towards a decanting channel arranged at one end of the basin, whereby the water surface is being scraped, at the decanting channel, the second position of the scraper blade, the scraper blade is elevated and returned step by step to said first po- sition.

At long basins or where much floating sludge is present, sever¬ al sleds with scraper blades can be installed on the same tra¬ verse beam, whereby all sleds are fed reciprocably using the same pushing axis. Hereby one feed from a first position which can be somewhere along the surface of the basin to a second po¬ sition closer to the decanting channel, and whereby a preced- ing scraper blade takes over the load, the floating sludge, from a blade behind and moves it forwardly.

By means of the present invention a solution for scraping of floating sludge is obtained which can be adopted carefully to the size and form of the intended basin.

The invention will now be described more in detail with refe¬ rence to the accompanying drawing wherein FIG. 1 shows an embodiment of the present invention seen from above ; FIG. 2 shows the device of FIG. 1 seen from the side; FIG. 3 shows the device of FIG. 1 seen from one of the short sides; FIG. 4 shows a longitudinal cross-section of the device of FIG.

1; and FIG. 5 shows a cross cross-section of the device of FIG. 1.

1 denotes a longitudinal basin where the water surface 5 with its floating sludge is restricted by two long sides 2, a rear short side 3 and a decanting channel 4.

Above the basin 1, a traverse beam 6 is attached to the one short side 3 and to bearing beams 7. To the traverse beam 6 a reductor motor 8 is fixedly arranged, which motor 8 is provided with an eccenter 9. To the eccenter 9 a slewing bracket 10 is pivotably mounted, as well as a pushing shaft attachment 11a, which in turn is arranged in a pushing shaft 11. The radius of the eccenter 9 is adapted to a desired stroke of the pushing shaft 11. The reductor motor 8, the eccenter 9 and the slewing bracket 10 are one embodiment of the driving means and can be replaced by a hydraulic cylinder, a pneumatic cylinder or the similar directly or indirectly connected to the pushing shaft 11. The pushing shaft 11 obtains a reciprocable movement (stroke) which in its forward movement drives a sled 12 for¬ wardly. A scraper blade 13 is hingedly mounted underneath the sled 12 whereby there is a turning switch 14 arranged on the sled 12. When the sled 12 with its scraper blade 13 closes the decanting channel 4 or another second turning point the turning switch 14 is arranged to abut a turning stop 15. Hereby the turning switch 14 pushes the blade upwards and locks it in an hinged position. The sled subsequently changes it direction of movement and transports the scraper blade 13, now in a hinged position, back over the water surface to a first position where the scraper blade is hinged downwardly by means of a second turning switch device, the movement of the sled is turned and a new scraping cycle can start.

By means of automatics in a cubicle (not shown) and limit switches in the first position the scraper/sled can be driven with a desired time interval and push in the first position. In order to introduce further automatics the decanting channel can be provided with a motor operation, whereby switches arranged on a desired distance from the decanting channel 4 provides a signal to the motor which operates the decanting channel 4 and tilts the decanting channel during the final phase of the scraping cycle.

In the foregoing it has been described how the pushing shaft 11 obtained its reciprocable movement (stroke). This movement is guided by guiding gliding shoulders 6a arranged in pairs in the traverse beam 6. Flat bar steels 11a are fixedly arranged to the pushing shaft 11. The flat bar steels 11a, the number of which is equal to the number gliding shoulders divided by two, and the length of which is equal with the stroke plus the length of the gliding shoulder, which facilitates mounting and demounting, runs in the tracks of the gliding shoulders 6a and guides the pushing shaft 11 in vertical direction, while the sides of the pushing shaft 11 run against the sides of the gliding shoulders 6a and guides the pushing shaft horizontally. Underneath the pushing shaft 11 there is a number of flat bar steels lie fixedly arranged, the number of which is depending on scraping length and stroke, and in each end of the pushing shaft 11 a bent flat bar steel lie is fixedly arranged, whereby the radius of the flat bar steel lie is adopted to the shape of a driving block 12d, whereby inside each flat bar steel lie there is a further flat bar steel lid fixedly arranged. The distance between the flat bar steels lid and lie is equal to the length of the driving block 12d plus a few millimetres.

The sled 12 is horizontally guided by four guiding blocks 12a, and vertically by the same guiding blocks 12a and four gliding blocks 12b. Two flat bar steels 12e are fixedly arranged at the centre of the sled 12. One driving block 12d is guided by said flat bar steel 12e and by a through-going shaft bolt 12f. The driving block 12d is characterized by its triangular form hav¬ ing rounded edges and its rounded arc-shaped slot opening through which the shaft bolt 12f is running. Underneath the sled 12 there are two bearings 12c arranged for suspending the scraper blade.

The length of the scraper blade 13 is adopted to the width of the basin and the height of the blade to the difference between low and top water surface 5. The scraper blade 13 is suspended via a shaft 13a in the bearings 12c of the sled 12. At the cen¬ tre of the front side of the scraper blade a turning switch lock 13b is fixedly arranged. A flat bar steel 13c is a tilting protector which is welded to the turning switch lock 13b, whereby its upper edge reaches the underside of the sled 12.

The switch lock 13b comprises of substantially triangular open¬ ing with three recesses arranged to receive a running roll 14c.

The turning switch 14 is guided by two guiders 14a running through the gliding blocks 12b. The guiders 14a are in the rear end thereof connected to a abutting plate 14b. The turning switch 14 is provided with a fork shaped under part which is connected by a shaft bolt with said running roll 14c running through the opening of the turning switch lock.

The material of the gliding shoulders 6a, guiding blocks 12a, gliding blocks 12b and bearings 12c is selected among different construction polymers, such as polyamide, polyacetal, or HD- polyethylene. There are somewhat higher demands on hardness and wearing strength with regard to the driving block 12d and the running roll 14c, whereby it has turned out that PAS LX can be a suitable material. PAS LX is a material based on polyacetal fused with finely divided additive of another polymer. Other materials should be stainless steel.

The function of the invention will be described in the follow- ing with reference to FIG. 4.

In FIG. 4 it is shown how the pushing shaft 11 with its flat bar steel lie pushes the driving block 12d, which together with the sled 12, and its scraper blade 13 and the turning switch 14 moves in scraping direction (to the right in FIG. 2) from a first position to a second position. The turning switch 14 reaches in the second position a turning stop 15. The pushing shaft 11 has hereby some further millimetres to move forward in the scraping direction. As the turning switch has come to a stop while the scraper blade 13 with its turning switch lock

13b move the running roll 14c to push the blade upwardly and to lock this in a hinged position.

The pushing shaft 11 hereby changes direction of movement and the flat bar steel lid pushes the left side of the driving block downwardly and raises its right side while the flat bar steel lie will come underneath the right side of the driving block. The flat bar steel lid then leaves the driving block and its right end falls down on the flat bar steel lie. By means of the movement of the flat bar steel lie the right end of the driving block 12d now glides upwardly towards the corner bet¬ ween the flat bar steel lie and the pushing shaft 11 simultan¬ eously as the driving block 12d glides on the shaft bolt 12f, the left part falls down against the sled, the driving block I2d pushes against the shaft bolt 12f and the returning move¬ ment of the scraper blade 11 has been started. The pushing shaft 11 changes direction of movement, the flat bar steel lie glides over the driving block 12d, the movement changes again and the flat bar steel lie pushes against the driving block 12d. This reciprocable movement of the pushing shaft 11 provides that each flat bar steel lie step by step moves the sled 12 with its scraper blade 13 until the abutting plate 14b reaches the turning stop 15 at the first position. The running roll 14c now moves from the lower locking point of the turning switch lock and the scraper blade falls by means of its own weight until a tilting protector 13c stops the movement when the scraper blade is in vertical position. The running roll then enters the upper locking point of the turning switch lock. When the pushing shaft then changes direction of movement the flat bar steels lid and lie to move the gravity point of the driving block as described above and the flat bar steel lie will step by step, feed the scraper blade 13 which now scrapes the floating sludge to the decanting channel 4.

Claims

CLAIM

1. A reciprocable scraping and transporting device for the mo¬ vement of floating sludge at settling basins (1) and the simi¬ lar at water purification plants, in particular sewage purifi- cation plants, characterized by a traverse beam (6) being plac¬ ed over and in the longitudinal direction of the basin, whereby a sled (12) is movably arranged to the traverse beam (6) and whereby the sled (12) is provided with a hinged scraper blade (13) suspended in the sled (12) and whereby the sled (12) is arranged to be reciprocably moved step by step by means of a pushing shaft (11) being arranged in said traverse beam (6), the movement of said pushing shaft (11) being generated by a driving equipment (8) and whereby the scraper blade (13) is ar¬ ranged to be present in the water surface (5) present in the basin ( 1 ) .

2. A reciprocable scraping device according to claim 1, charac¬ terized in that a switch lock (13b) arranged to said scraper blade (13) comprises a substantially triangular opening with three recesses arranged to receive a running roll (14c) for moving said scraper blade (13) up and down.

3. A reciprocable scraper device according to claim 1, charac¬ terized in that the sled (12) is provided with a movable driv- ing block ( 12d) , which driving block comprises a substantially triangular, equally sided block with blunt angle, which block is further provided with a centrally arranged arc-shaped recess opening.