WO2014131516A2

WO2014131516A2 - Process and apparatus for manufacturing an oil absorbing device

Info

Publication number: WO2014131516A2
Application number: PCT/EP2014/000508
Authority: WO
Inventors: Winfried A. Riedel; Bettina Krohn
Original assignee: Riedel Winfried A
Priority date: 2013-02-28
Filing date: 2014-02-26
Publication date: 2014-09-04
Also published as: WO2014131516A4; DE202013012854U1; DE202013001956U1; DE102013017796A1; WO2014131516A3

Abstract

A process for manufacturing a floatable oil absorbing device comprises: - cutting a non-woven polymeric master web into pieces; - collecting a predetermined amount of the pieces; - placing the predetermined amount of the pieces onto a bottom sheet of an envelope material; - placing a top sheet of an envelope material on the predetermined amount of the pieces and the bottom sheet; and - heat-sealing or welding peripheral regions of the top and bottom sheets together to form the device.

Description

PROCESS AND APPARATUS FOR MANUFACTURING AN OIL ABSORBING

DEVICE

The present invention relates to an apparatus for the manufacturing of a floatable oil absorbing device, and the device so manufactured.

Known oil absorbing devices, such as the one disclosed in US 3,904,528, which have a single block of absorbent material disposed in a sleeve-like envelope. This known device has a water-impervious outer material. It has turned out that in practice, this device has insufficient oil-absorbing properties.

It is also known, e.g. from DE 23 63 396 Al, to cut a preformed block of foam material into suitably sized pieces, to be covered by an envelope fabric to form a pillow or mattress. Such a process is limited to single-block foam material.

The present inventors have found that in order to provide reasonable oil absorbing properties, it is crucial that contaminated water may have access to the bulk of the oil absorbing device, which means that the oil absorbing material should be particulate, in the forms of strips or chips, and neither monolithic nor granular or globular. In order to manufacture a device having a water-pervious envelope loosely filled with a particulate oil absorbing material, the known apparatus proved wholly unsuitable.

In order to solve the problem of being able to manufacture an efficient floatable oil absorbing device, the present invention provides the process of claim 1, and the apparatus of claim 9. The resultant device is defined in claim 18, and the oil absorbing material in claim 14.

The apparatus comprises a cutting section for continuously cutting particles out of a master web of oil absorbing material, an apportioning section for collecting and forwarding a predetermined amount of the particles, and a transporting section in turn comprising an input sector for positioning the predetermined amount onto a bottom sheet of envelope material, a welding sector for placing a top sheet of water-pervious envelope material onto the predetermined amount of the particles, and heat-sealing peripheral regions of the top and bottom sheets, and an output sector, from which the heat-sealed disk is removed from the transporting section, wherein the transporting section is arranged to move the devices being so manufactured from each sector to the next, and from the final sector to the first, in a concerted fashion. This apparatus is able to quasi- continuously produce efficient oil absorbing devices each containing hundreds or thousands of particles/pieces of oil absorbing material, leaving sufficient interstices between the particles that water may ingress into the bulk of the device, and may carry entrained oil to the oil absorbing particles. Typically, the predetermined amount of oil absorbing particles or pieces is allowed to fall freely onto the bottom sheet, without compressing the resulting heap more than inevitable by the weight of the top sheet before welding the peripheral rims of the sheets together.

In embodiments, the transporting section comprises a number of fixtures, each adapted for mounting one device being manufactured. The transporting section may comprise a turn-table arranged for rotatingly moving the devices between sectors. Such a turn-table may have recesses formed in its surface as fixtures. By these means, it is feasible to move plural semi-finished devices from one assembling position to the next in a concerted fashion.

In embodiments, the cutting section comprises engaging cutting rolls, the surface of which carries cutting tools arranged for cutting particles out of the master web. In some embodiments, one of a pair of rolls acts as a knife, and the opposing roll acts as an anvil. In other versions, both rolls act together in a scissor-like fashion.

According to another aspect of the invention, an oil absorbing material consists of generally oblate chips of a fibrous polymeric material, wherein the shape of the chips, in a projection onto their plane of maximum extension, is polygonal or/and has one angle exceeding 180°. It is not necessary that the chips are strictly planar, although it is typical that they are, stemming from a planar web. The polygonic shape provides pointed corners keeping the chips from arranging in stacks with small overall surface. The points tend to attach to faces of neighboring particles due to the fibrous nature of the polymeric material. The more pointed, the more spacious are the created interstices, wherefore in embodiments, two angles of the polygon are not more than 100°, or are less than 75°. In some embodiments, it suffices to provide internal corners, namely corners having angles exceeding 180°. Such internal corners provide interstices within themselves. Where even multiple internal corners are present, a star-like structure results.

In embodiments, the ratio of the equivalent diameter of the chips to their thickness is at least 5, or more than 8, but less than 20. In this range, the stability of the chips is sufficiently large that they remain largely planar in the environment in the device, yet are still able to hold the neighboring pieces at the required distance.

In embodiments, the polymeric material is a polyolefin or melt-blown polypropylene. This material has a very good oil absorbing property, yet is available at an affordable price.

According to a further aspect of the invention, which is related to the preceding aspect, a water-floatable oil absorbing device comprises the oil absorbing material described above, wherein the chips are accommodated between two sheets, at least one of which is water-pervious, wherein the two sheets are welded together at their peripheries. In this manner, it is ensured that water and the oil entrained therein have access to the oil absorbing material in the first place, but the oil absorbing material cannot escape from between the sheets.

In some embodiments both sheets are water- and oil-pervious. This structure is most suitable for applications on the water surface, where access is required from the top and from the bottom. In other embodiments, the bottom sheet is oil-impervious, which structure is most suitable for on-shore applications such as on a beach to be protected from spilt oil. Waves splashing on the devices spread out on the beach will carry the oil onto the devices, but the oil is absorbed and does not leak through the bottom sheet of the devices.

In some embodiments, the outer contour is generally obround, oval or circular. Such devices can readily be stacked to provide generally cylindrical modules, which can be connected to chains. To this end, in some embodiments the two sheets each have a hole for passing a rod or tube therethrough.

In other embodiments, an outer contour is generally polygonal. Such devices can readily be connected at their rims to form a two-dimensional array covering an area. To this end, they may comprise plural peripherally arranged connectors, which may be of a male/ female connecting type. Typical numbers of connectors are seven, eight, or more than eight, such as up to twelve. If there are eight of them, they may be distributed around the circumference of a quadrangular device either one at each corner and one on each side centrally, such as in the central third; or else two on each side, located in the outer thirds of the respective side. In either case, a most regular fashion is achieved, so that each device can readily be connected with other, like devices, without cumbersome reorientation.

In order to further improve on the stability of the distribution of the particles in the device even under the action of waves and the like, a central connection between the two sheets may be provided. This effectively urges the particles into an annular space provided in the device, and counteracts any tendency to the forming of agglomerates.

The process for manufacturing the floatable oil absorbing devices accordingly comprises cutting a non-woven polymeric master web into pieces; collecting a predetermined amount of the pieces; placing the predetermined amount of the pieces onto a bottom sheet of an envelope material; placing a top sheet of an envelope material on the predetermined amount of the pieces and the bottom sheet; and heat-sealing or welding peripheral regions of the top and bottom sheets together to form the device. The supply of the master web can be made continuous, because the collecting step forces the subsequent steps to occur intermittently, allowing some time e.g. for the positioning of the pieces on the bottom sheet or the welding of the peripheries.

In embodiments, in a subsequent step the top and bottom sheets are mutually connected in a central region, to provide a stabilized distribution of the particles in the envelope. Connectors may be attached to a rim portion of one of the sheets, e.g. a welded portion or a portion to be welded if the attaching is done beforehand, for later being able to mutually connect several devices (mats or pillows) to form a two-dimensional array, in an edge-on fashion.

In other embodiments, the top and bottom sheets are each provided with a hole (beforehand, during the process, or afterwards), and the completed device is mounted on a rod or tube together with other, like devices in a face-on fashion as a stack, such that the rod or tube fits into the holes and the pieces cannot escape from within the devices. Such a stack of devices (disks) may be placed in a rigid cage having end parts and peripheral parts connecting the end parts. Plural such stacks or cages can be connected, with plural further devices arranged between the facing end parts of the stacks or cages.

In a combination of the latter two embodiments, mats or pillows having peripheral connectors are connected to stacks or cages, using matching connector mounted e.g. on the cage. In this combination, the cages may form a linear barrier, and the mats connected thereto may form a carpet. Such a structure is very efficient in absorbing oil from the surface of inshore water bodies, or even offshore. The invention will be described below referring to the following drawings:

Figure 1 showing a top view of an inventive device;

Figure 2 showing a stack of inventive devices;

Figure 3 showing a top view of an inventive device;

Figure 4 showing another inventive device; and

Figure 5 showing a schematic view of the apparatus.

According to the first embodiment of Figure 1, a number of 15-25 individual disks 3 is stacked on a common center rod or tube 5, to form a generally cylindrical module 1. The stack is held together by end grids 7, which end grids are in turn connected by a number of 3-8 outer tubes 17 (in the example, 5 tubes are shown). The end grids 7 may have a star shape as shown (with 5 radial struts 19, one of which is shown dashed). The end grids may be made of a solid, hollow, or porous plastic material. The center tube may be replaced by a rope tightened between the end grids, which in turn may be replaced by disks or concentric rings.

With respect to Figure 2, each individual disk 3 is round in shape and doughnut- shaped in cross section, having an outer peripheral region in which the thickness gradually tapers towards the rim. Each disk has faces made of grid-like polyethylene sheets, and an interior made up of polypropylene (and/or polyethylene) non-woven (such as melt-blown) web chips. The polyethylene grids may have a weight of 300-400 g/m², with openings of 3-10 mm mean size, and/or 5-12 mm pitch; or 5-8 mm mean size and/or 7-10 mm pitch. The chips may be less than 7 cm down to 4 cm or even down to 1 cm in length, 10-50 mm in width, and 0.5-5 mm in thickness, e.g. more than 2 mm up to 5 mm. In some applications, the thickness may be less than 1 mm down to 0.5 mm. Generally, the width/ thickness ratio is in the range 1.5-10, with 3-5 preferred. In one variant, the non-woven polyolefin material is relatively thin, having an area weight of about 120 to 240 g/cm² and is cut into elongated strips, the aspect ratio (length divided by equivalent diameter, i.e. the diameter of a circle having the same area as the cross-section) of which is more than 5 or even 8. The circularity (the ratio of the minimum diameter to the maximum diameter at some cross-section; equals 1 for a cylinder) of such strips may be in the range of 0.2 to 0.95. In another variant, a thicker non-woven polyolefm material having an area weight of more than 240 to 480 g/cm² is cut into polygonal, pointed chips of a generally oblate shape. In this case, the ratio of the equivalent diameter of the chips to their thickness d'platyness") is at least 5, or more than 8. It seems that such polygonal, in particular trigonal or quadrigonal chips tend to form large spaces between each other, into which spaces water can flow and can transport any oil to the absorbing chips. For this to occur, it is desirable if at least two corners of each chip have angles of not more than 100°, or less than 75°. Suitable shapes are substantially equilateral triangles, trapezoidals, parallelograms, diamond shapes, squares and rectangles. If pentagons, hexagons or higher polygons are employed, it is preferred that irregular or non-regular shapes with at least two acute angles are chosen.

While the size D of the disks depends on the intended use, it has been found that 30-100 cm is most useful, with 40-70 cm preferred. The overall diameter D' of the module will be slightly larger, by about 5 to 10 cm. The strip-shaped (or chip- shaped) absorber material (250-350 g for a 50-60 cm sized disk) allows for a loose packing avoiding dense clots. Therefore, water may pass relatively unrestrictedly through the bulk of the module, the created turbulence carrying the oil to the absorber. Around the central opening, the front and back grids may be welded together, or connected by some connecting structure as e.g. a plastic bushing, or in embodiments can be left unconnected if the size of the opening sufficiently closely matches the outer diameter of the rod, tube or rope inserted into it so that the absorbent strips (or chips) cannot pass through any gap formed. The method of manufacturing the individual disks includes placing a suitable amount of the oil absorbent polypropylene (and/or polyethylene) strips (or chips) onto a lower grid-like polyethylene sheet, then placing a like sheet on top, and welding the sheets together at their peripheral rims 21. The amount of the strips is such that a center thickness of each disk is about 2 to 5 cm. In some embodiments, the central opening is then punched with or without forming a weld or other connection between the upper and lower grids. In other embodiments, the central openings are formed before the welding together of the grids, or at the same time.

In the embodiment shown in Figure 1, 25 disks are housed inside each module 1, with 5 further disks 15 mounted on an outward extension of the center rod 5, held by an end disk 9 of the rod. Two cables 11 (polypropylene) with hooks 13 are led through two (non-adjacent ones) of the 5 outer tubes 17, for connecting adjacent modules 1 to one another. In the connected state, the 5 external disks 15 fill the space between adjacent modules 1. In this manner, a chain of modules 1 can be disposed transverse to the expected drift of spilt oil, the oil everywhere encountering an oil absorbing module 1. A typical size of a module would be 0.5 m to 1 m in length L including the 10-20 cm extension L" for the outer disks 15 (length of main body L'=L-L").

Each module of this type can absorb more than 100 1 and up to 150 1 of oil, e.g. 110-120 liters for a module 60 cm in diameter and 75 cm in length, weighing only 12 kg dry. It may be noted that on account of the low density of the plastic material of 950-965 kg/m³ and the air entrapped between the fibers the inventive structures have sufficient buoyancy to float even in fresh water, more so in salt water. The bulk of the structures will, however, gradually sink below sea level as oil is absorbed and entrapped air is displaced, and therefore is able to continue absorbing oil from the water passing through it, while no oil can pass through underneath the modules.

In the second embodiment of Figure 3, a generally rectangular or square mat 10 is shown, with top and bottom sheets of the same grid-like polyethylene material as described above, and also the same filling of oil absorbing polypropylene strips. In this example, the rims of the pillow are folded (indicated by dashed lines), and eyes 22 (circular or oval as shown) formed therethrough to provide connectability. Welding the rims may be dispensable where the eyes 22 are configured to secure the rims against unintended reopening. Folding the rims may also be dispensable where the weld connection is sufficiently sturdy in itself, or is enhanced by connectors attached to the unfolded rims. Such connectors are described below.

Such mats 10, the size of which may vary e.g. between 50 cm and 100 cm side length, can easily be interconnected to form a two-dimensional array of in principle unlimited size. In one approach, such interconnected mats are folded atop one another in the shape of a stack, ready to be unfolded when used. In this manner, it is possible to quickly dispose large numbers of mats onto an oil- contaminated water surface or beach area, while still being able to later recollect the oil-filled mats as easily. Each mat of this type, containing about 2 kg/m² of absorbing material, may absorb more than 10 1 and up to 20 1 of oil, e.g. 16 1 per m².

In the embodiment of Figure 4, there are two connectors (male 23' and/or female 23") on each side of a polygonal mat 20, for providing a connection across the edge. In one example, one (male) connector 23' extends beyond the edge, and one corresponding (female) connector 23" extends only almost up to the edge of the mat 20. In another example, there are two or three male connectors on each one of opposing edges, and two or three female connectors on the other opposing edges. Other regular arrangements are also possible. In the embodiment shown, the peripheral parts 25' are welded together, the central region 25" being stuffed with the absorbing material strips or chips described above, in a non-ordered and non-compressed fashion, so that large interstices are deliberately formed between the strips (or chips). Bending of the strips is desirable, as long as the strips entangle each other. In the embodiment shown, there is also a central loop 27 formed through holes 29 in the bottom sheet and through the top grid, in order to provide enhanced stability and keep the absorber filling (in area 25") in place during handling of the mat 20.

It is also contemplated to use mats of this type together with the modules, in order to absorb the spilt oil when it has accumulated upwind (or upstream) of a chain of the modules of the invention. Figure 5 indicates that the master web 100 is supplied from above to the nip between two cutting rolls 102', 102", one of which may be an anvil roll. The cuttings fall into the basket 104 with which a scales is associated. Alternatively in a high- technology version, the particles may actually be counted by optical means. After the proper predetermined amount has been collected, i.e. also after a certain time, the bottom 105 of the basket 104 is opened and the cuttings fall onto a first fixture 108 on the turn-table 106. Onto the place I where the cuttings fall, a bottom sheet of the device is placed just before the opening of the basket bottom. After a brief settling time of a few seconds, e.g. 2 to 9 seconds, the turn-table rotates by an integer fraction - in the example shown, a third - of a full revolution, to position the bottom sheet with the cuttings heaped thereon below II an annular welding device 110. Just before the welding device 110 is lowered, the top sheet is placed on the heap and bottom sheet, to become welded to the bottom sheet at their rims. Meanwhile, of course, the next bottom sheet is placed below I the basket 104 etc. The fixtures may include mere recesses in the top surface of the turn-table, or may include more sophisticated means for fastening the bottom sheet to the turn-table, depending on the requirements due to the maximum rotational speed of the turn-table. Generally, the energy loss during braking steps may be electrically or mechanically stored by recuperating means, to be used during the subsequent accelerating steps.

In a final rotation about the same rotational angle and in the same time frame, the welded device is moved to an output position III, from where it is removed from the turn-table to free the corresponding fixture. All the supply and removal actions (indicated by double arrows) may individually be accomplished manually or automatically. In variants which are not shown, the full revolution of the turn-table is divided into more fractions such as four 90° steps, allowing e.g. one of the previously described steps to be split into two sub-steps, if that is more convenient. In principle, only two steps are required, but it may be inconvenient to dispense with the final step III, requiring instead immediate removal of the finished device from the turn-table to free the fixture for the next. In particular with manual supply operation, at least three or four steps are more recommendable.

The time required to complete a full revolution evidently is three times the standstill time plus six times the acceleration/deceleration time, in the example shown. This time is required to produce three devices. Taking the time for acceleration/deceleration to be each one half second, it can be seen that on the basis of 2 to 9 seconds standstill time, the entire time per each device is 3 to 10 seconds, or 6 to 20 devices per minute, equaling 360 to 1200 devices per hour and therefore, not taking into account maintenance time, 8.640 to 28.800 per day. In general, it is contemplated to produce about 8.000 to 30.000 device per day of operation in this manner.

In some embodiments, the individual devices are combined into modules of e.g. 25 devices each (20 within each cage, 5 between adjacent cages). The above numbers result into about 320 to 1200 modules per day of operation, or about 200 to 900 m of barrier length. In the case of quadrangular mats arranged for being interconnected to form a two-dimensional array, the area covered is the crucial number: Assuming each mat to cover an area of about half a square meter, the above manufacturing numbers translate into about 4.000 to 15.000 m² per day of operation.

The knife parts of the cutting roll or rolls may include one set of parallel, spirallike knives wound around the roll. In a variant, this set is zig-zagged. In order to be able to cut acute-angled particles from the master web, a second set of shorter knives is arranged between the first set, at the prescribed acute angles. A perpendicular angle is also envisaged. The knives of the second set may, but need not all be parallel; instead, they may consist of two sub-sets having individually parallel knives, but at an angle with each other as well as with the first set. In this manner, e.g. trapezoidal particles may be cut. The knives of the second set or sets may, but need not be staggered, i.e. not contiguous where they abut the knives of the first set. If they are parallel, evidently the shape of the particles will be that of parallelepipeds. Broadly related rolls are known from European patent 1 612 011 B1. The skilled person will be aware of possible alterations or modifications to the above exemplary description, which are possible without deviating from the scope of the appended claims.

Claims

1. A process for manufacturing a floatable oil absorbing device, the process comprising:

cutting a non-woven polymeric master web into pieces;

collecting a predetermined amount of the pieces;

placing the predetermined amount of the pieces onto a bottom sheet of an envelope material;

placing a top sheet of an envelope material on the predetermined amount of the pieces and the bottom sheet; and

heat-sealing or welding peripheral regions of the top and bottom sheets together to form the device.

2. The process of claim 1, further comprising mutually connecting the top and bottom sheets in a central region.

3. The process of claim 1 or 2, further comprising attaching connectors to a rim portion of one of the sheets.

4. The process of claim 3, wherein plural devices are connected in an edge- on fashion using the connectors to form a two-dimensional array .

5. The process of claim 1, further comprising providing the top and bottom sheets each with a hole, and mounting the device on a rod or tube together with other, like devices in a face-on fashion as a stack, such that the rod or tube fits into the holes and the pieces cannot escape from within the devices.

6. The process of claim 5, further comprising placing the stack of devices in a rigid cage having end parts and peripheral parts connecting the end parts.

The process of claim 6, further comprising connecting plural stacks, with plural further devices arranged between the facing end parts of the stacks.

The process of one of claims 5 to 7, comprising connecting other devices to the stacks, wherein the other devices are manufactured according to claim 3 or 4.

An apparatus for manufacturing a water-floatable oil absorbing device, the apparatus comprising: a cutting section for continuously cutting particles out of a master web of oil absorbing material; an apportioning section for collecting and forwarding a predetermined amount of the particles; and a transporting section comprising:

an input sector for positioning the predetermined amount onto a bottom sheet of envelope material;

a welding sector for placing a top sheet of water-pervious envelope material onto the predetermined amount of the particles, and heat- sealing peripheral regions of the top and bottom sheets; and

an output sector, from which the heat-sealed disk is removed from the transporting section,

wherein the transporting section is arranged to move the devices being so manufactured from each sector to the next, and from the final sector to the first, in a concerted fashion.

The apparatus of claim 9, wherein the transporting section comprises a number of fixtures, each adapted for mounting one device being manufactured.

11. The apparatus of claim 9 or 10, wherein the transporting section comprises a turn-table arranged for rotatingly moving the devices between sectors.

12. The apparatus of claim 11, wherein the turn-table has recesses formed in its surface as fixtures.

13. The apparatus of one of claims 9 to 12, wherein the cutting section comprises engaging cutting rolls, the surface of which carries cutting tools arranged for cutting particles out of the master web.

14. An oil absorbing material, consisting of generally oblate chips of a fibrous polymeric material, wherein the shape of the chips, as seen in a projection onto their plane of maximum extension, is polygonal or/and has one angle exceeding 180°.

15. The oil absorbing material of claim 14, wherein two angles of the polygon are not more than 100°, or less than 75°.

16. The oil absorbing material of claim 14 or 15, wherein the ratio of the equivalent diameter of the chips to their thickness is at least 5, or more than 8.

17. The oil absorbing material of one of claims 14 to 16, wherein the polymeric material is a polyolefin, such as melt-blown polypropylene or polyethylene.

18. A water-floatable oil absorbing device, comprising the oil absorbing material of one of claims 14 to 17, wherein the chips are accommodated between two sheets, at least one of which is water-pervious, wherein the two sheets are welded together at their peripheries.

19. The device of claim 18, wherein both sheets are water- and oil-pervious.

20. The device of claim 18, wherein the bottom sheet is oil-impervious.

21. The device of one of claims 18 to 20, wherein an outer contour is generally obround, oval or circular.

22. The device of claim 21, wherein the two sheets each have a hole for passing a rod or tube therethrough.

23. The device of one of claims 18 to 20, wherein an outer contour is generally polygonal.

24. The device of claim 23, further comprising a central connection between the two sheets.

25. The device of claim 23 or 24, further comprising peripherally arranged connectors adapted to interconnect plural devices to form a two- dimensional array.

26. The device of claim 25, wherein the connectors are of a male/female connecting type.

27. The device of claim 25 or 26, wherein the connectors are three to seven, eight, or more than eight, such as up to twelve in number.

28. The device of claim 27, wherein eight connectors are distributed around the circumference of a quadrangular device either one at each corner and one on each side centrally, such as in the central third; or else two on each side, located in the outer thirds of the respective side.