GB2119668A - Clarification apparatus - Google Patents

Abstract

A settling tank for clarifying dirty water comprises a cylindrical upper part enclosing an annular baffle 8 defining an annular inlet space with a tangential inlet 15, a central overflow 10 for clarified water and a conical lower part with rotary scrapers 22, 23 directing settled sludge towards outlet 4. The scrapers are rotated by a shaft 18 which is connected to drive motor 19 by a Cardan joint 20 and supported by end bearing 25 and intermediate bearing 26. The bearings (Figs. 3, 4) are each enclosed by an inverted cup, rotating with the shaft 18 and maintaining a trapped body of air which excludes dirty water or sludge from the bearings themselves. <IMAGE>

Description

SPECIFICATION Clarification and concentration apparatus The invention relates to a clarification and concentration installation for the clarification of dirty water and water from industrial processes, consisting of a cylindrical vessel with conical point and sludge outlet, outer and inner tubes arranged with spacing in the upper part, between which the dirty water is conducted downwards and diverted, and. the driven shaft equipped with scrapers and guided by an end bearing and intermediate bearing.

In the clarification of dirty water, especially industrial waste water, clarification and concentration installations are frequently used in which rabbling mechanisms are operated to avoid caked-on deposits in the region of the conical point and the discharge. For this purpose on the shaft reaching to the lowermost point of the conical vessel there are fitted scrapers which are rotated at low speed and scrape over the slope of the clarification and concentration installation. On account of the overall height of such clarification and concentration installations, of 10 metres or more, the shaft of a known rabbling mechanism is guided by intermediate bearings and an end bearing. Secure guidance and maintenance-free operation however are guaranteed only if the intermediate bearings and the end bearing are not impaired by the sludge particles, which are sometimes very abrasive.Friction can also occur due to the harmful influence of sludge particles containing such industrial wastes, leading to rapid damage to the bearing and especially also to overloading of the drive. Furthermore the operation of such clarification and concentration installations is impaired in that when the dirty water current is fed from above, caked-on deposits occur on the fittings in the clarification and concentration installation, which are finally detrimental to the directed guidance of the dirty water current in the direction of the point and thus the sinking of the dirt particles. It is then not possible to maintain an aimed flow.

The invention is based upon the problem of producing a maintenance-free clarification and concentration installation which ensures an improved separation result which is uniform even with a differing occurrence of sludge.

The problem is solved according to the invention in that the shaft is formed as a Cardan shaft and guided by end and intermediate bearings which are enclosed by an upwardly closed hollow cylinder connected with the shaft, and in that the inlet of the dirty water is attached tangentially to the outer tube, which is arranged at a short distance from the inner tube.

With a clarification and concentration installation of such formation the dirty water is introduced in directed manner tangentially into the region between outer and inner tubes, expediently obliquely downwards, so that a downwardly directed flow of spiral form results within this cavity between the two tubes. This has the consequence that the dirt particles sink away early, so that after the diversion of the water current an extensive clarification has already taken place.

Since a very large cross-section is available for the return flow of the already partially clarified water, a retardation occurs which gives even the finest sludge particles sufficient time and opportunity to sink away in the direction of the sludge discharge.

The clarification result of such a clarification and concentration installation is correspondingly improved, and maintenance-free operation is possible due to this formation and the special formation of the end and intermediate bearings and of the shaft itself. The end and intermediate bearings are advantageously formed as dry bearings so that even in the case of maximum sludge loading they always run with the rubbing and guiding parts in the region not impaired by the dirty water or sludge.

A further favourable arrangement is achieved in that the shaft is connected through a Cardan joint with the drive motor. Thus the drive motor itself remains unaffected by irregular loadings of all kinds. The long shaft can carry out lateral movements, being adequately guided by the end bearing and the intermediate bearings. The shaft is here connected with the drive motor through the Cardan joint which is arranged above the water overflow. In this way stressing of the Cardan joint is avoided and it is advantageously easily accessible.

The length of the inner tube inserted into the outer tube and thus into the vessel and thus also the distance between the two can be varied. It is advantageous here to hold the inner tube on the outer tube, through spacing members in staggered arrangement, at a distance which is less above than below. It is advantageous to make the distance variable. Thus a retardation of the water current, leading to sinking away of the sludge particles, already takes place in the cavity formed between inner tube and outer tube.

A simple and expedient, that is especially also maintenance-compatible, formation is to be seen in that the clean water inlet takes place into an angular or round inlet channel which is made vertically adjustable. A uniform outflow of the purified water is possible, and the inlet channel can be adjusted so that the water runs in uniformly everywhere. Thus it is also possible if desired to adapt the height of the settling zone well to the conditions in each case.

According to an advantageous development of the invention the lower end of the shaft is formed as an upwardly closed hollow cylinder into which the plunger with head is introduced. The hollow cylinder is thus integrated in an advantageous manner into the shaft, and it is not even necessary absolutely to make the shaft as a hollow shaft, but rather the hollow cylinder can also be produced by an appropriate bore. Since the weight of the shaft and of the rabbling mechanism as a rule is taken up through the Cardan joint by the axial bearing of the drive motor, the bearing arranged at the lower end of the clarification and concentration installation does not serve as a support bearing but only as a directional bearing, so that if the hollow shaft is closed off by an appropriate plate this does not have to take up any weight.The air situated in the downwardly open hollow cylinder acts as a cushion so that water or sludge and water can advance into the cavity only until the air pressure in this region is just as great as the pressure of the water-sludge mixture. Under the existing conditions in such clarification and concentration installations the basis can be adopted that the available air volume is compressed to about half.

Regarding the intermediate bearing it is advantageous to connect a hollow cylinder with the shaft, into which cylinder the bracket resting on the support strut is introduced. Such an intermediate bearing can readily take up the occurring forces, since the parts subject to friction lie in the dry zone, as in the end bearing likewise.

In order to be able adequately to take up the further occurring forces and to guarantee secure guidance of the shaft, according to a further development of the invention it is provided that the plunger head of the end bearing and the bracket of the intermediate bearing are coated with thermosetting synthetic plastics material and/or carry a sleeve, or that the sleeve is inserted into the hollow cylinder.

If expedient or necessary, the plunger head and in addition the inner wall of the hollow cylinder can also be coated with synthetic plastics material, so that like materials advantageously rub on one another, leading to minimum possible wear and thus practical freedom from maintenance.

Since in the embodiment according to the invention it is ensured that the parts which rub cannot be damaged by sludge or water, according to a further development of the invention it is provided that the head of the end or intermediate bearing has one or more roller bearings. Under the existing conditions roller bearings can be operated practically without maintenance, so that this solution also leads to the advantageous clarification and concentration installation working with low maintenance or no maintenance.

The invention is especially distinguished in that with increased separation and clarification effect of the clarification and concentration installation, and thus an increased yield of sludge, a secure and maintenance-free guidance and corresponding drive of the shaft of the rabbling mechanism is given. This is advantageous especially in such clarification and concentration installations, because naturally maintenance of the fittings is possible only with the installation halted and after the contents have been let off, which thus leads in each case to considerable operational problems.

The present invention is thus distinguished by a very high technical progress.

Further details and advantages of the object of the invention appear from the following description of the accompanying drawing, in which a preferred example of embodiment is illustrated with the details and individual parts necessary thereto, and wherein:- FIGURE 1 shows a clarification and concentration installation in section, FIGURE 2 shows a clarification and concentration installation in plan view, FIGURE 3 shows an end bearing in section and FIGURE 4 shows an intermediate bearing in section.

Figure 1 shows the clarification and concentration installation in overall view, its vessel 1 being divided into a cylindrical part 2 and a point 3 with sludge outlet 4. The rabbling mechanism 5 is arranged centrally. The entire vessel 1 rests on three or more supports 6 or a continuous pedestal frame.

The vessel 1 is formed in the upper part as outer tube 7 in which an inner tube 8 is arranged.

An inlet 9 for the dirty water or industrial process water is provided tangentially into the cavity formed between the outer and inner tubes 7 and 8, Figure 2 especially clarifying the tangential inlet of the dirty or process water.

The dirty or process water is set into a spiral movement due to the tangential introduction through the pipe 15, and accordingly conducted slowly downwards, whereby dirt particles are already separated and sink away. The operation is favoured and influenced by the fact that the distance between inner and outer tubes 7, 8 increases from above downwards. The distance can be modified according to the conditions in each case. After passing the diversion 13 the water is deflected upwards and can then flow back in the direction of the water overflow due to the very large cross-section. By reason of the widening of cross-section a retardation of the flow occurs so that a further separation of dirt particles and sludge occurs.

As is also clarified by reference to Figure 2, the water overflow is formed by several preferably round or angular inlet channels 10 approximately in the middle of the vessel 1: The outflow pipe is then conducted downwards parallel with the shaft 1 8 and then emerges from the tube jacket or from the outer tube 7. It is possible here to arrange the inlet channel 10 in such a way that the outflow pipe 14 then no longer extends maintenancefreely parallel with the shaft 18.

The shaft 18 is guided at a plurality of points at the bottom 16 and in distribution over its length. It is driven by the drive motor 19 with which it is connected through the Cardan joint 20.

At the lower end of the shaft 18 the latter is provided with several scrapers 22, 23 in order to avoid caked-on deposits in the region of the point 3. In the lower region the kneading mechanism 24 is arranged close above the end bearing 25.

The end bearing 25, arranged on the bottom 16, and the intermediate bearing 26, arranged on the support strut 27, will be explained further with reference to Figures 3 and 4. The Figures here clarify that the sludge particles separated in the cavity between outer and inner tubes 7, 8, which cavity is formed and determined by the spacing members 29, 30 holding the inner tube 8, and also the water itself cannot be detrimental to the bearings in the region of the end bearing 25 and the intermediate bearing 26, because these are formed as dry bearings.

Figure 3 shows the formation of the end bearing 25 which is enclosed by the hollow cylinder 33. The hollow cylinder 33 is here the lower end 34 of the shaft 18 which is formed as hollow shaft and closed off by the partition. On the inside of the hollow shaft a sleeve 37 can be arranged which consists of synthetic plastics material. An embodiment is illustrated in which the sleeve 37 surrounds the head 36 of the plunger 35 and can readily rub on the hollow cylinder. The indicated water level 41 lies so that the surfaces and parts rubbing on one another are not thereby impaired.

The same effect is achieved in an intermediate bearing 26 in that the shaft is connected with a downwardly open hollow cylinder 39 which encloses the intermediate bearing 26. The intermediate bearing 26 is here formed by a bracket 38 which, connected with the support strut 27, extends into the hollow cylinder 39 and carried for example roller bearings 38 at the upper end. The roller bearings 38 in this case likewise lie in the dry region, as clarified by the indication of the water level 41.

Claims (9)

.CLAIMS

1. Clarification and concentration installation for the clarification of dirty water and industrial process water, consisting of a cylindrical vessel with conical point and sludge outlet, outer and inner tubes arranged with spacing in the upper part, between which the dirty water is conducted downwards and diverted, and of the driven shaft fitted with scrapers and guided by an end bearing and intermediate bearings, characterised in that the shaft (18) is fo#rmed as a Cardan shaft and guided by end bearings (25) and intermediate bearings (26) which are enclosed by an upwardly closed hollow cylinder (33, 39) connected with the shaft, and in that the inlet (9) of the dirty water is attached tangentially to the outer tube (7) which is arranged at a short distance from the inner tube (8).

2. Clarification and concentration installation according to Claim 1, characterised in that the shaft (18) is connected with the drive motor 119) through a Cardan joint (20) arranged above the water overflow (10).

3. Clarification and concentration installation according to Claim 1, characterised in that the inner tube (8) is held, by means of spacing members (29, 30) in staggered arrangement, on the outer tube (7) at a shorter distance at the top than at the lower end.

4. Clarification and concentration installation according to Claim 1, characterised in that the clean water overflow takes place into an angular or round entry channel (10) which is vertically adjustably arranged.

5. Clarification and concentration installation according to Claim 1, characterised in that the lower end (34) of the shaft (18) is formed as an upwardly closed hollow cylinder (33) into which the plunger (35) with head (36) is introduced.

6. Clarification and concentration installation according to Claim 1, characterised in that a hollow cylinder (39) is connected with the shaft (18) and the bracket (40) resting on the support strut (27) is introduced into this cylinder.

7. Clarification and concentration installation according to Claim 5 or Claim 6, characterised in that the plunger head (35 and 36) of the end bearing (25) and the bracket (40) of the intermediate bearing (26) are coated with thermosetting synthetic plastics material and/or carry a sleeve (37) or in that the sleeve is inserted into the hollow cylinder (33, 39).

8. Clarification and concentration installation according to Claim 5 or Claim 6, characterised in that the head (36) of the end bearing (25) or intermediate bearing (26) comprises one or more roller bearings (38).

9. Clarification and concentration installation substantially as described with reference to the accompanying drawings.