GB2193443A

GB2193443A - Settling tank

Info

Publication number: GB2193443A
Application number: GB08718553A
Authority: GB
Inventors: Dennis Claude Smith
Original assignee: SHOBNALL ENGINEERING Ltd
Current assignee: SHOBNALL ENGINEERING Ltd
Priority date: 1986-08-05
Filing date: 1987-08-05
Publication date: 1988-02-10
Also published as: GB8619104D0; GB8718553D0

Abstract

Solid waste is removed from water which has been used in potato peeling plant by feeding the water through a vibrating screen 40 into a settling tank 10. The screen removes most of the solids, and the rest is recovered from tank 10 by an endless chain scraper (not shown) which runs up the inclined floor 18. Clean water overflows walls 14, 16 indirectly and directly into reservoir 24, from which it can be recycled to the plant. <IMAGE>

Description

SPECIFICATION Waste product recovery This invention relates to a method of, and apparatus for, automatically recovering waste products from a process which produces a substantially liquid waste material. The invention particularly relates to the vegetable processing industry and is especially designed for use with a potato peeling system.

Traditional vegetable processing plants use a considerable amount of water, as fresh water is constantly supplied with no water being recycled. This high fresh water usage may be relatively expensive and in areas where fresh water is at a premium may not be permitted. Another consideration relating to such plants is the quality of water permitted to be discharged therefrom. In the case of a potato peeling system the discharge from the system will include a considerable quantity of starch which may, subsequent to discharge, solidify blocking pipes or raising the level of streams or river beds.

According to the present invention there is provided apparatus for automatically recovering waste products from a process producing a substantially liquid waste material, the apparatus comprising a vessel, means for supplying waste material to the vessel, and means for removing from the vessel solid materials settled out of the liquid.

Preferably the vessel has-at least one sloping surface extending the whole depth thereof.

Desirably the solid material removing means includes one or more scraping bars movable along the length of said sloping surface. The or each scraping bar may extend across said sloping surface and be attached to driven continuous line means.

Preferably the vessel communicates with a container which may allow for collection and re-use of the remaining liquid. A weir may be provided around at least part of an upper edge of the vessel remote from the solid material removal means to enable communication with the container.

Means for removing solid material above a predetermined size may be provided in the waste material supply means.

Also according to the present invention there is provided a method of automatically recovering waste products from a process producing a substantially liquid waste material, the method comprising supplying waste material to a vessel, allowing settling out of solid materials from the waste material, and removing the solid materials from the vessel.

Preferably the settled out solid material is removed from the vessel by moving one or more scrapers along a surface of the vessel until a side edge of the vessel is reached.

Solid material above a predetermined size may be removed from the waste material prior to supply thereof to the vessel.

Liquid is preferably discharged from the vessel into a container for re-use in the process.

The liquid may be discharged over a top edge or edges of the vessel remote from where the solid materials are removed from the vessel.

The invention further provides a vegetable preparation process including a method of automatically recovering waste products from the process as described in any of the three preceding paragraphs.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which; Figure 1 is a side view of apparatus according to the invention; and Figure 2 is a perspective view of the apparatus of Fig. 1.

Referring to the drawings which show apparatus suitable for use with the waste materials from a potato peeling system, a tank 10 has four sides 14-18 upstanding from a base 12.

Three of the tank sides 14, 16 are perpendicular to the base 12 while the beach side 18 slopes upwardly at a predetermined angle away from the base 12. The two sides 14 adjacent to the beach side 18 are mirror images of each other. The end of the tank 10 adjacent to a top edge 20 of the beach side 18 is supported by a frame 22 such that the opening at the top of the tank 10 is substantially horizontal in use.

A reservoir 24 is provided externally of the tank side 16. The reservoir 24 comprises a base 26 and three sides 28, 30 upstanding vertically therefrom and incorporating the side 16 of the tank 10 as a fourth side. The reservoir sides 28 align with the sides 14 of the tank 10, and the other side 30 extends between the sides 28 parallel to the side 16 of the tank. The sides 28, 30 are slightly taller than the sides 14, 16 of the tank. A pipeline (not shown) connects with the reservoir 24 for pumping out of water for re-use.

Running along each of top edges 32 of the tank sides 14 external of the tank 10, from a respective one of uprights 34 of the frame 22 to the reservoir 24 and communicating therewith, is a channel 36 formed by lengths of ''L'' shaped angle iron 38. Mounted on a top end of the upright 34 is a sieving frame 40 which mounts a vibratory screen and a chute (both not shown).

Extending in planes parallel and adjacent to internal faces 42 of the tank sides 14 are two continuous loops of chain 44, best illustrated in Fig. 1. The chain loops 44 are mounted on two pairs of ratchets 46, 48, a first of the pairs of ratchets 46 being mounted adjacent to the base 12 of the tank. The second pair of ratchets 48 (not shown in Fig. 2) is mounted externally of the tank 10 such that the chain loops 44 run substantially parallel to the beach side 18. Tensioning means (not shown) for the chain loops 44 may be fitted to the second pair of ratchets 48.

Mounted transversely between the chain loops 44 are a plurality of scraper bars 50 of a thickness to contact the beach side 18 when on a lower pass 50 of the chain loops 44. The chain loops 44 are driven by a motor (not shown). A suitable container (not shown) is located beneath the top edge 20 of the beach side 18.

In use, the reservoir 24 is filled with water for use in peeling and cleaning and other activities. Waste material, for example from a potato peeling system, is pumped through the vibratory screen into the tank 10, the vibratory screen removing most of the peelings and soil from the waste material which is directed down the chute. The waste material is pumped in at a predetermined rate to ensure maximum settling out of solid material therefrom. When the tank 10 is full water pours over the sides 14, 16 thereof into the channels 36 and thereby into the reservoir 24, or directly into the reservoir 24. The provision of side and end weirs reduces the velocity of the water in the tank.

The starch and other solid materials settling out of the waste material drop onto the beach side 18 and are automatically and continuously pushed up the beach side 18 by the scraper bars 50 until passing over the top edge 20 of the beach side 18 to drop into a suitable receptacle (not shown).

The water entering the reservoir 24 is of a quality suitable for re-use in washing and peeling potatoes and also to wash down work surfaces. If this water is discharged into the waste drain it is more likely to be of an acceptable quality for discharge than prior to passing through the tank. A further cleaning stage for the water may be cheaply added such as a biological filter. The waste products recovered by this process can be spread onto fields as fertilizer, or the vegetable matter can be used as animal feed.

This invention obviates or mitigates the need for civil engineering work in providing large settling tanks. The apparatus is free standing and robust and can thus be cited anywhere and needs very little maintenance or supervision. The apparatus is of basic construction and thus may be relatively cheaply constructed.

Various modifications may be made. For example the reservoir may be omitted from the apparatus. If soil free animal feed and starch are required a second tank in series with a first may be used. In certain uses the vibratory screen may be omitted. Any# suitable means for removing the settled out starch material from the beach side may be employed.

Claims

1. Apparatus for automatically recovering waste products from a process producing a substantially liquid waste material, the apparatus comprising a vessel, means for supplying waste material to the vessel, and means for removing from the vessel solid materials settled out of the liquid.

2. Apparatus according to claim 1, in which the vessel has at least one sloping surface extending the whole depth thereof.

3. Apparatus according to claim 2, in which the solid material removing means operates along the length of said sloping surface.

4. Apparatus according to any of claims 1 to 3, in which the solid material removing means includes one or more scraping bars.

5. Apparatus according to claim 4 when dependent on claim 3, in which the or each scraping bar extends across said sloping surface and is attached to driven continuous line means.

6. Apparatus according to any of the preceding claims, in which the vessel communicates with a container which allows for collection and re-use of the remaining liquid.

7. Apparatus according to claim 6, in which a weir is provided around at least part of an upper edge of the vessel remote from the solid material removal means to enable communication with the container.

8. Apparatus according to any of the preceding claims, in which means for removing solid material above a predetermined size is provided in the waste material supply means.

9. A method of recovering waste products from a process producing a substantially liquid waste material, the method comprising supplying waste material to a vessel, allowing settling out of solid materials from the waste material, and automatically removing the solid materials from the vessel.

10. A method according to claim 9, in which the waste material is pumped into the vessel at a predetermined rate to ensure maximum settling out of solid materiais.

11. A method according to claim 9 or 10, in which the settled out solid material is removed from the vessel by moving one or more scrapers along a surface of the vessel until a side edge of the vessel is reached.

12. A method according to any of claims 9 to 11, in which solid material above a predetermined size is removed from the waste material prior to supply thereof to the vessel.

13. A method according to any of claims 9 to 12, in which liquid is discharged from the vessel into a container for re-use in the process.

14. A method according to claim 13, in which the liquid is discharged over a top edge or edges of the vessel remote from where the solid materials are removed from the vessel.

15. A vegetable preparation process including a method of automatically recovering waste products from the process according to any of claims 9 to 14.

16. Apparatus for automatically recovering waste products from a process producing a substantially liquid waste material substantially as hereinbefore described with reference to the accompanying drawings.

17. A method of automatically recovering waste products from a process producing a substantially liquid waste material substantially as hereinbefore described with reference to the accompanying drawings.

18. Any novel subject matter or combination including novel subject matter disclosed in the foregoing specification or claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.