Method for processing oil filters

Abstract

 Method for processing used oil filters, characterized in that the method comprises the following steps:

• the introduction of a first volume of oil filters into a compression chamber,
• a first compression step, compressing the oil filters to a second volume from a first direction,
• a second compression step, compressing the oil filters from the second volume to a third volume from a second direction which differs from and is not opposite to the first direction, at speed, and
• keeping the pressure constant until sufficient oil has leaked out.

Description

Field of the invention

[0001] The subject of the invention is an oil filter press with which used oil filters can be reduced in size and with which the oil which is still present in the used oil filters can be recovered with a high yield.

State of the art

[0002] An oil filter essentially comprises a filter paper which is situated inside a casing. This casing is usually made of steel and generally speaking is relatively well sealed. When processing used oil filters, the residual oil has to be removed from the filters, as does the filter cloth. Various documents provide a description of a press for used oil filters in which the residual fraction of oil is separated as far as possible from the filter. One example of these documents is the description given in US 5,060,564, which describes an appliance which compresses an oil filter. Similar devices are described in US 4,927,085, US 5,383,397 and various other documents.

[0003] The appliances described in these documents are always only able to compress a limited number of filters, generally only one, at any one time. There are two main reasons for this. Firstly, the systems demand a specific shape of the appliance and a well-defined position where the oil filter is to be placed. As a result, automation will always result in a relatively slow process, while an unautomated system will be particularly labour-intensive. Also, to some extent the process is dependent on the shape and size of the filter. All this results in a relatively inflexible, slow and expensive procedure for compressing oil filters.

[0004] An additional problem of the prior art is that the filters can never be 100% recycled, since a relatively high proportion of the oil remains in the steel casings, while the filter paper definitely remains in the casings. A standard way of processing such compressed steel oil-filter casings is to melt them down to produce steel. However, if excessive oil remains, the batch will be rejected and everything will have to be degreased using organic solvents, with all the additional costs and environmental pollution which this entails.

Aims of the invention

[0005] The object of the invention is to develop an oil-filter press which separates the oil and, if appropriate, the filter paper from the steel casings to a sufficient extent. An additional object of the invention is for this all to take place automatically and in a single step.

General description of the invention

[0006] A main feature of the invention is a method for processing used oil filters, characterized in that the method comprises the following steps:

• the introduction of a first volume of oil filters into a compression chamber,
• a first compression step, compressing the oil filters to a second volume from a first direction,
• a second compression step, compressing the oil filters from the second volume to a third volume from a second direction which differs from and is not opposite to the first direction, at speed, and
• keeping the pressure constant until sufficient oil has leaked out.

[0007] In a particular embodiment, the first and second directions are perpendicular to one another. The first direction is preferably vertical, the second direction preferably horizontal.

[0008] In a following embodiment of the invention, the time for which the pressure is kept constant may be variable. This time is preferably at least 40 seconds.

[0009] In a following embodiment of the invention, the second compression step is carried out at a pressure of between 270 and 330 bar.

[0010] A particular embodiment is characterized in that the method can be carried out automatically.

[0011] Another main feature of the invention is a press for processing used oil filters, characterized in that the press comprises the following components:

• a compression chamber, delimited by four solid walls and two compression blocks,
• a first compression cylinder, which is connected to a first compression block, with the result that the first compression cylinder can exert a pressure in a first direction on the material situated in the compression chamber,
• a second compression cylinder which is connected to a second compression block, with the result that the second compression cylinder can exert a pressure in a second direction on the material situated in the compression chamber, the second direction being different from and not opposite to the first direction,
• a control system for the press which allows the pressure generated to be kept at a fixed level for a specific time.

[0012] The press may be characterized in that the first and second directions are perpendicular to one another.

[0013] In a particular embodiment, the first compression cylinder exerts pressure in the vertical direction.

[0014] In a particular embodiment, the second compression cylinder exerts pressure in the horizontal direction.

[0015] Preferably, the pressure generated may be maintained for a variable time and may be maintained preferably for at least 40 seconds.

[0016] The second compression cylinder is able, in a particular embodiment, to generate a pressure of more than 270 bar.

[0017] A further characteristic of the invention is an installation for compressing used oil filters, characterized in that the installation contains a press according to the invention or which is able to carry out the method according to the invention.

[0018] The installation may furthermore be characterized in that it comprises a comminution installation.

[0019] Another characteristic of the invention is formed by compressed oil filters, characterized in that they may be obtained by means of the method or using a press according to the invention. The filters preferably contain only 1% of oil after compression.

[0020] Another characteristic of the invention is used oil, characterized in that it is obtained by means of the method or a press as described above.

Brief description of the figures

[0021] Figures 1, 2 and 3 respectively describe a front view, a side view and a top view of a press according to the invention.

[0022] Figure 4 shows a compression block which can be used in a press according to the invention.

[0023] Figure 5 describes a continuous processing system for used oil filters in which two presses according to the invention are used.

[0024] Figures 6 and 7 respectively illustrate a top view and front view of a double feed hopper.

Detailed description of the invention

[0025] The method will be described with reference to examples. These examples are embodiments and do not limit the invention.

[0026] Figures 1 and 2 illustrate a press according to the invention. The method according to the invention will be described with reference to the operation of the press shown in these figures.

[0027] The first phase of the compression is the filling phase. A predetermined volume of oil filters (see below), which is situated in the feed hopper (2) , is introduced into the compression chamber (5) by opening the feed door (7). The feed door (7) is closed again. The compression chamber (5) is defined by four solid walls, the vertical compression block (3) and the horizontal compression block (4) . As an example, the compression chamber at this time can measure 1130 × 200 × 500 mm. The second phase is the vertical compression. The vertical compression block compresses the oil filters owing to the fact that the vertical compression cylinders (1) exert a pressure equivalent to 70 tonnes. This first compression continues until the volume of the compression chamber is 1130 × 200 × 200 mm. The height at which the vertical compression block is now situated is no longer changed. In the third phase, the horizontal compression is carried out at speed. The horizontal compression cylinder starts to apply a pressure of approximately 300 bar and, via the horizontal compression block (4) further compresses the oil filters to a volume of 300 × 200 × 200 mm. This state (high pressure) is maintained for at least 40 seconds (rapid speed), so that the oil and pulp (from the paper filters) can run out of the compressed oil filters to a sufficient extent. The final phase is the removal of the pressure and opening of door (8), so that the compressed block of oil filters can be removed. In this example, the compression chamber is filled with 45 to 80 filters (depending on the individual sizes) . Approximately 2500 l of oil are recovered from ten tonnes of filters. Analysis of the compressed oil filters in accordance with the resolution of the Flemish Executive of 30.07.1982 and the decree of 02.07.1981 has determined that the residual oil content in the compressed oil filters is 1%.

[0028] For a continuous system, it is possible to operate with two presses, as illustrated in Figures 3 and 5.

[0029] Figure 4 shows a possible embodiment of a horizontal compression block (4). The cutouts (11) provide for more rapid and improved removal of the oil and pulp from the compression chamber.

[0030] Thus far, only the press has been described, but a complete system requires additional considerations. In practice, the situation is never ideal. The waste which is to be processed contains not only the collected (intact) oil filters, but also other waste which can be divided into short, coarse and fine contaminants and oil-containing waste which can be cut up. Figure 5 shows a processing system which is able to sort and process the waste as it arrives from the refuse collector. It is unloaded onto a horizontal conveyor belt (41) which removes short pieces of waste from the waste while it is being conveyed to the storage bunker (43) via the transportation belt (42). The transportation belt (42) is set in such a way that fine contaminants are removed from the stream of waste. In the storage bunker (43) the coarse contaminants are removed. Via a continuous conveyor belt (44), the rest of the waste is guided to the sorting belt (45), where the oil filters (metal casings) and the oil-containing waste which can be cut up are separated. The latter waste is conveyed, via a transportation belt (46), to a shredder (47), where this waste is cut up into pieces with a maximum size of 15 mm. The oil-containing waste which has been cut up is collected in containers (48) and can be reused, for example as fuel in the cement industry. Via the transportation belt (53) the oil filters are distributed between the feed hoppers (52) by means of the distribution flap (54). Two identical presses (50 and 51) are filled successively. The oil filters are compressed, inter alia, by means of the main compression cylinders (49), which are specially provided for high pressure and rapid working. While the oil and filter paper pulp which has been squeezed out is collected below the presses, the compressed oil filters are removed via guide tracks (56) and, via a transportation belt (58), are stored in containers (57). The oil filters can be reused in the steel industry.

[0031] In order to be able to continuously feed a system with two presses, a distribution system is required. This distribution system is described in Figures 6 and 7. The oil filters which are supplied from the transportation belt (53), depending on the position of the distribution flap (54), fall into the left-hand feed hopper (12) or the right-hand feed hopper (22). The distribution flap (54) is controlled by means of sensors which measure whether the quantity of filters is situated above the line (13). In this way, there is always a specific quantity of oil filters in the feed hopper and a press cannot be overloaded.

Claims

1. Method for processing used oil filters, characterized in that the method comprises the following steps:

- the introduction of a first volume of oil filters into a compression chamber,

- a first compression step, compressing the oil filters to a second volume from a first direction,

- a second compression step, compressing the oil filters from the second volume to a third volume from a second direction which differs from and is not opposite to the first direction, at speed, and

- keeping the pressure constant until sufficient oil has leaked out.

2. Method according to Claim 1, characterized in that the first and second directions are perpendicular to one another.

3. Method according to Claim 1 or 2, characterized in that the first direction is vertical.

4. Method according to one of Claims 1 to 3, characterized in that the second direction is horizontal.

5. Method according to one of Claims 1 to 4, characterized in that the time for which the pressure is kept constant is variable.

6. Method according to one of Claims 1 to 5, characterized in that the time for which the pressure is kept constant is at least 40 seconds.

7. Method according to one of Claims 1 to 6, characterized in that the second compression step is carried out at a pressure of between 270 and 330 bar.

8. Method according to one of Claims 1 to 7, characterized in that the method can be carried out automatically.

9. Method according to one of Claims 1 to 8, characterized in that oil and paper pulp are squeezed out.

10. Press for processing used oil filters, characterized in that the press comprises the following components:

- a compression chamber, delimited by four solid walls and two compression blocks,

- a first compression cylinder, which is connected to a first compression block, with the result that the first compression cylinder can exert a pressure in a first direction on the material situated in the compression chamber,

- a second compression cylinder which is connected to a second compression block, with the result that the second compression cylinder can exert a pressure in a second direction on the material situated in the compression chamber, the second direction being different from and not opposite to the first direction,

- a control system for the press which allows the pressure generated to be kept at a fixed level for a specific time.

11. Press according to Claim 10, characterized in that the first and second directions are perpendicular to one another.

12. Press according to Claim 10 or 11, characterized in that the first compression cylinder exerts pressure in the vertical direction.

13. Press according to one of Claims 10 to 12, characterized in that the second compression cylinder exerts pressure in the horizontal direction.

14. Press according to one of Claims 10 to 13, characterized in that the pressure generated can be maintained for a variable time.

15. Press according to one of Claims 10 to 14, characterized in that the pressure generated can be maintained for at least 40 seconds.

16. Press according to one of Claims 10 to 15, characterized in that the second compression cylinder is able to generate a pressure of greater than 270 bar.

17. Installation for compressing used oil filters, characterized in that the installation contains a press according to one of Claims 10 to 16 or which is able to carry out a method according to one of Claims 1 to 9.

18. Installation according to Claim 17, characterized in that it furthermore comprises a comminution installation.

19. Installation according to one of Claims 17 or 18, characterized in that it furthermore comprises a shredder installation.

20. Compressed oil filters, characterized in that they may be obtained by means of the method according to one of Claims 1 to 9 or using a press according to one of Claims 10 to 16.

21. Compressed oil filters according to Claim 20, characterized in that they contain approximately 1% of oil.

22. Used oil, characterized in that it is obtained by means of the method according to one of Claims 1 to 9 or using a press according to one of Claims 10 to 16.

Drawing