GB2354457A

GB2354457A - Rotary drum filter with a pair of spaced rollers

Info

Publication number: GB2354457A
Application number: GB9922260A
Authority: GB
Inventors: Brian Hagan
Original assignee: CARIER BULK MATERIALS HANDLING
Current assignee: CARIER BULK MATERIALS HANDLING
Priority date: 1999-09-22
Filing date: 1999-09-22
Publication date: 2001-03-28
Anticipated expiration: 2019-09-22
Also published as: GB0226492D0; GB2378401A; GB2354457B; GB9922260D0

Abstract

A solid/liquids separator comprises a rotary drum 12 in the form of a sieve, a spaced pair of rollers 16, 16A and a single spring 18 at each end of the drum which acts through a linkage mechanism to press both rollers against the drum with equal pressure so that liquid can be squeezed from material, such as agricultural slurry. Preferably the linkage mechanism comprises an arm 30 which carries the shafts of both rollers 16, 16A on a pivot axis 32 and a lever 34 which is fixed at one end to the machine frame by a pivot 36. Preferably an adjustable compression spring 18 is fixed at the other end of the lever 34. A spring urged scraper 24 may act upon the exterior of the drum with variable pressure. The drum 12 may be perforated or wire mesh. Internal rollers 14, 14A may oppose the external rollers 16, 16A and they can be mounted on demountable beams (26, 26A, figure 1) on to which the springs 18 may also be attached. The drum 12 can be driven by at least one of the external rollers 16 or an internal shaft. Liquid may be collected either internally or from beneath the drum.

Description

2354457 Solids/Fluids Separator This invention relates to a solids/fluids

separator of the kind having a rotary drum in the form of a sieve against which bears a pair of spaced rollers, in use for squeezing material to be treated against the rotating drum.

According to the invention, there is provided a solids/fluids separator of the kind described, wherein a single spring at each end of the drum acts through a linkage mechanism to press both rollers against the drum with at least approximately equal pressures.

Separators of the kind described are commonly used for squeezing liquids out of slurries, such as slurries produced on farms out of the wastage of animals and crops. In use, the fluid passes through the drum wall and is collected, while solids are usually scraped from the drum wall and separately collected. The resulting liquid can then be used as a fertiliser by spreading over fields, and the solids can be stored in a pit or tank much smaller than that which would be required for the original slurry.

Typically, in separators of the kind described, separate springs are used at each end of the drum to press the respective spaced rollers against the drum, but it has now been found that advantages can be gained when only a single spring is employed at each end of the drum, firstly in making the machine easier to set up for treatments of differing types of slurry, and secondly in making the drum less susceptible to damage when stones and like non-squeezable solids are encountered in the slurry being treated.

Preferably, the two rollers are mounted on shafts carried by an arm having a pivot axis centrally positioned between the two shafts, and the two springs, one at each -2end of the drum, act on the pivot of the arm to urge it towards the drum.

At each side of the machine, i.e. each end of the drum, the spring preferably acts on the pivot of the roller-carrying arm via a lever. The lever preferably has a fixed pivot to the machine frame at or near one end, and the spring acts on the lever at or near its other end. The spring is preferably a compression spring, and acts on the said other lever end to urge the lever about its fixed pivot so that the pivot of the roller-carrying arm is urged approximately along the line joining said pivot of the roller-carrying arm and the axis of the drum.

The tension of the springs, one at each side of the machine, is preferably adjustable to enable the pressure with which the rollers press against the drum to be varied, e.g. to suit different kinds of slurry. It is also to be noted that when a stone or the like is encountered in the slurry, damage to the drum is minimised, because the increase in roller pressure on the drum is effectively halved.

Most preferably, a scraper acts on the exterior of the drum to remove adhering solids. The scraper is preferably spring urged against the drum exterior, and adjustment means may be provided to vary the pressure of the scraper against the drum.

The drum may be of the perforated type, or a wedge wire type, dependent upon the application and the degree of filtration required.

Squeezed-out liquids may be collected within the interior of the drum, or the liquids may pass twice through the wall of the drum and be collected beneath it.

Preferably, at least in the case of perforated drums, internal rollers are provided to support the drum at the positions where the external pressure rollers are acting. However, the drum could alternatively be supported on a shaft carried by the machine frame. In the former case at least, one of the external pressure rollers may be employed to drive the drum in rotation. In the latter case, the drum may be driven in rotation via its supporting shaft.

Another important feature of the solids/liquids separator of the invention is the use of two beams mounted to the machine frame, one at each end of the machine, to support the internal rollers or the supporting shaft (when provided). These beams may conveniently also serve as fixture points for the ends of the springs for the external pressure rollers, so that by removing one supporting beam (thus releasing the spring pressure on the external rollers) and lowering the other supporting beam, for which purpose a bolt and slot arrangement between the beam and the machine frame may be provided, and also by propping up the internal rollers with a suitable tool, a damaged drum can readily be removed and replaced. This is a major advantage arising from supporting the drum on internal rollers, and driving the drum in rotation via at least one of the external pressure rollers.

The solids/fluids separator in accordance with the invention is further described with reference to the accompanying drawings, in which:- Figure 1 is a partial front view of the separator; Figure 2 is a side elevational view of the separator showing some details; and Figure 3 is also a side elevational view of the separator, but showing further details.

Referring to the drawings, a machine frame 10 houses a sieve drum 12, which may be of the perforated type or the wedge wire type.

The machine frame carries two spaced rollers 14, 14A which support the drum internally, by engagement with the underside of the wall of the drum at the top, the internal rollers being equally spaced on opposite sides of a vertical plane through the drum axis.

The frame also supports a pair of angularly spaced rollers 16, 16A, urged against the exterior of the sieve drum, in opposition to the internal rollers, by springs 18, a single spring at each side of the machine, i.e. each end of the drum. The spring arrangements at the two sides of the separator are generally similar, and the later description of the spring arrangement on one side applies equally to the other.

One of the external rollers 16 or 16A is driven in rotation at one side of the machine, and drives the other external roller (16A or 16) by means of a chain drive, so that in use the rollers 16, 16A drive the sieve drum 12 in rotation.

The internal rollers 14, 14A are also rotated.

In use, slurry fed into the top of the machine, preferably via a weir, is squeezed between the rotating drum 12 and the also rotating external pressure rollers 16, 16A. Liquids pass through the drum wall and are collected either internally, as indicated at 22, or pass twice through the drum wall to be collected beneath the drum.

A scraper 24 is pressed with adjustable spring pressure against the exterior of the drum to remove adherent solids, which are separately collected.

The separator as thus far described is substantially conventional except in that a single spring 18 is employed at each side of the machine to urge the external pressure rollers against the drum.

At each side of the machine, the machine frame carries a beam 26, 26A supporting shafts for the internal rollers 14, 14A. These supporting beams 26, 26A also provide fixing points for one end of each of the springs 18 which act on the external pressure rollers 16, 16A. Figure 1 shows at one end of the sieve drum 12 the supporting beam 26 carying the internal roller shaft, and at the other end of the sieve drum the supporting beam 26A providing a fixing point 28 for one of the springs 18, but in practice it will be understood that at each side of the machine the supporting beams 26, 26A each serve for both purposes. Spring fixing points 28 are adapted to provide for adjustment of pressure of the springs 18 acting on the extemal rollers 16, 16A, e.g. to suit different types of slurry.

Preferably the arrangement is such that the springs 18 cannot be so far adjusted as to lock solid. As the spring arrangements at both sides of the separator, i.e. at both ends of the sieve drum, are substantially the same, the following description of Figures 2 and 3 showing one side of the machine will suffice.

The shafts for the external rollers 16, 16A, one of which is power driven from a motor in order to rotate the drum, are carried by opposite ends of an arm 30 having a central pivot 32. Pivot 32 is also positioned at the centre of a lever 34 having a fixed pivot 36 to the machine frame at one end. Spring 18 acts on the other end of the lever 34. The pivot 32 is thus urged approximately vertically downwardly centrally between the external rollers 16, 16A, towards the axis of the sieve drum 12. The spring pressure acting on the two external rollers 16, 16A is thus approximately equally divided between said rollers. Thus, adjustment of the pressure of the spring 18 serves simultaneously for both rollers, whilst if a stone or other solid object passes into the nip between the rollers and the drum, the increase in squeezing pressure at the nip is effectively halved, substantially reducing the risk of damage to the drum.

At least at one side of the machine, the supporting beam 26 and/or 26A is mounted to the machine frame by a vertical bolt and slot arrangement 38. By demounting one of the beams 26, 26A and lowering the other (thus releasing the spring pressure on the external rollers 16, 16A), whilst propping up the internal rollers 14, 14A with a suitable tool, the sieve drum 12 is freed for ready removal from the machine frame, e.g. for maintenance and/or replacement.

Various modifications of the above-described arrangement are possible within the scope of the invention as defined by the appended claims. The use of the single spring arrangement acting on the pair of extemal pressure rollers at each side of the separator is applicable to many known machines of the kind described, whether an external roller or the sieve drum itself is power driven and whether or not internal drum supporting rollers are employed.

Claims

1. A solids/fluids separator of the kind described, wherein a single spring at each end of the drum acts through a linkage mechanism to press both rollers against the drum with at least approximately equal pressures.

2. A separator according to claim 1, wherein the two rollers are mounted on shafts carried by an arm having a pivot axis centrally positioned between the two shafts, and the two springs, one at each end of the drum, act on the pivot of the arm to urge it towards the drum.

3. A'separator according to claim 2, wherein, at each side of the machine, the springs acts on the pivot of the roller-carrying arm via a lever.

4. A separator according to claim 3, wherein the lever has a fixed pivot to the machine frame at or near one end, and the spring acts on the lever at or near its other end.

5. A separator according to any of claims 1 to 4, wherein the spring is a compression spring.

6. A separator according to claim 4 or claim 5, wherein the spring acts on the said other lever end to urge the lever about its fixed pivot so that the pivot of the roller-carrying arm is urged approximately along the line joining the pivot of the roller-carrying arm and the axis of the drum.

7. A separator according to any of claims I to 6, wherein the tension of the springs, one at each side of the machine, is preferably adjustable to enable the pressure with which the rollers press against the drum to be varied, e.g. to suit -8different kinds of slurry.

8. A separator according to any of claims 1 to 7, wherein a scraper acts on the exterior of the drum to remove adhering solids.

9. A separator according to claim 8, wherein the scraper is spring urged against the drum exterior, and adjustment means may be provided to vary the pressure of the scraper against the drum.

10. A separator according to any of claims 1 to 9, wherein the drum is of the perforated kind or the wire mesh kind.

11. A separator according to any of claims 1 to 10, wherein liquids are collected from inside the drum.

12. A separator according to any of claims 1 to 10, wherein liquids are collected from beneath the drum.

13. A separator according to any of claims 1 to 12, wherein internal rollers are provided to support the drum at the positions where the external pressure rollers are acting.

14. A separator according to claim 13, wherein at least one external roller is used to power drive the drum in rotation.

15. A separator according to claim 14, wherein the power driven roller is opposed through the wall of the drum to an internal roller.

16. A separator according to any of claims 1 to 15, having two beams mounted to the machine frame, one at each end of the machine, to support the internal -9rollers (when provided).

17. A separator according to claim 16, wherein the beams also serve as fixture points for the ends of the springs for the external pressure rollers.

18. A separator substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows Claims 1. A solids/fluids separator of the kind having a rotary drum in the form of a sieve against which bears a pair of rollers in spaced stationary positions around the drum, in use for squeezing material to be treated against the drum, wherein a single spring at each end of the drum acts through a linkage mechanism to press both rollers against the drum with at least approximately equal pressures.

3. A separator according to claim 2, wherein, at each side of the machine, the springs acts on the pivot of the roller-carrying arm via a lever.

5. A separator according to any of claims I to 4, wherein the spring is a compression spring.

7. A separator according to any of claims I to 6, wherein the tension of the springs, one at each side of the machine, is preferably adjustable to enable the pressure with which the rollers press against the drum to be varied, e.g. to suit different kinds of slurry.

8. A separator according to any of claims I to 7, wherein a scraper acts on the exterior of the drum to remove adhering solids.

11. A separator according to any of claims I to 10, wherein liquids are collected from inside the drum.

12. A separator according to any of claims I to 10, wherein liquids are collected from beneath the drum.

13. A separator according to any of claims I to 12, wherein internal rollers are provided to support the drum at the positions where the external pressure rollers are acting.

16. A separator according to any of claims 1 to 15, having two beams mounted to the machine frame, one at each end of the machine, to support the internal rollers (when provided).