WO2016209097A1

WO2016209097A1 - A method for repeated production of a filter cartridges

Info

Publication number: WO2016209097A1
Application number: PCT/PL2015/000103
Authority: WO
Inventors: Włodzimierz PIŁACIŃSKI; Janusz ROSŁOŃ
Original assignee: Secura BC Sp zoo
Current assignee: Secura BC Sp zoo
Priority date: 2015-06-22
Filing date: 2015-06-29
Publication date: 2016-12-29
Anticipated expiration: 2017-12-22
Also published as: PL412799A1

Abstract

The present invention provides a method for the repeated production of a filter cartridge equipped with a reinforcing mesh core including steps of applying repeatedly cyclic core on a rotating shaft, then moving a new core along the central shaft towards the spraying head in such manner, that cores rotating with shaft are continuously moved under the spraying head, and so forming a fibrous layer on the core, then cutting of thus formed filters using a rotating knife. The present invention provides also a device for production of filter cartridges equipped with a rigid, perforated core.

Description

A method for repeated production of a filter cartridges

The present invention provides a method for the repeated production of a filter cartridges equipped with a reinforcing mesh core, and a device for production of filter cartridges equipped with a rigid, perforated core.

Filter cartridges for fluids manufactured from polypropylene using the melt-blown method have become the standard method of water cleaning. Such cartridges are manufactured by forming the filtration layer of fibres around a central core, and then cutting thus created structure in sections of desired length.

KR101478241 discloses a melt-blown type device for production of cylindrical filter cartridges, in which a moving plate is formed, intended to be moved on a bearing plate in all directions. Additionally, a repeated production method is described, using stacking of polymer fibres of various sizes.

US2002025397 describes filter cartridges with a core made of non-filtrating, self- bearing fibrous mass of infinite length, synthetic, polymeric continuous fibres, a core and at least a single layer of ring-type filtration zone. The fibrous core is produced in situ during production of the filter cartridge in a melt-blowing process using a mixture of synthetic fibres of the polymeric core supplied towards the forming core. A device for continuous filter production has also been disclosed. Such a device includes a melt- blowing system, a drive unit rotating the initial cast along its longitudinal axis, in a specific direction, and in order to provide axial transfer of the initial cast along the process direction with a specific axial speed; a cutting system located behind the melt-blowing system for cutting the initial cast off and obtaining the filter cartridge, whereby the cutting unit contains a cutting element and a bearing element in order to enable simultaneous motion of the cutting device parallel to the longitudinal axis of the initial form when the cutting device is moved towards and away from the initial cast, transversely to its longitudinal axis.

US5910229 provides devices and methods in which thermoplastically formed cartridges are welded co-axially at their ends in such a manner that the basic elements are provided as an integral structure. Elongated elements comprise perforated pipe elements made of a thermoplastic material and used as base elements for production of cylindrical filter cartridges using the melt-blown technique. As such, integrally joined base elements may be rotated and individually against the melt-blown nozzle during repeated production of infinite cylindrical filtrating elements using the melt-blown technique.

Patent PL212007 provides a method in which during production of pneumothermal electret fibres, the polymer is mixed with a powdered bactericidal directly at the outlet of air nozzles spraying the polymer in the fibre-producing head and the bactericidal agent is dosed in a controlled manner to the fibre-producing head, centrally and symmetrically, to the fibre-producing zone. A device for production of electret pneumothermal fibres including a pressing device, a connector, a fibre-producing head connected to an air heater and to a collecting device comprising a mesh with a fan generating vacuum conditions, wherein a feeding chute of the bactericidal agent is located over the head body with a variable, adjustable rotation speed engine drive attached to it, connected to a worm cartridge located centrally in the axis of the head body using a worm cylinder and which passes through the entire length of the head body, whereas the head body is a cylinder on the external surface of which a spiral groove is present, having constant cross-section along its entire length, and the head core is connected to a group of polymer nozzles using a threaded bushing, whilst the worm cylinder is attached to the head body using a cap, and additionally the head body is equipped in its upper part in an additional stub for hot air supply connection to air openings located in the head core, and a filter is installed at the outlet of vacuum generating fan, under a fibre-collecting mesh.

Solutions known in the art have at least two disadvantages: the production process is slowed down by the exchange operation performed on sequentially produced cartridges leaving the forming machine, application of new cores on the receptacle of the forming machine, both ends cut off from the newly produced cartridges and generation of wastes in the form of cut off cartridge ends. Providing a continuous method of filter cartridges production equipped with a reinforcing core could allow the aforementioned disadvantages to be eliminated.

Repeated production should include uniform motion of empty cores and continuous cartridges forming on said cores under the spraying head forming a stream of fibres, with said motion being additionally coordinated with the operation of cutting the cartridges to the desired length.

Solution of this technical problem has been in the centre of attention of production technologists. Surprisingly, a concept was developed, which solves the problem of continuous core feeding under the fibre-forming head without the need to stop the production process. Moreover, a special mechanism ensuring axial motion of the formed cartridges with controlled speed required for production of various cartridge types was developed. Additionally, stability of motion of the quickly rotating fibre reception system collecting fibres supplied by the spraying head was also ensured. The long, rotating shaft of variable thickness made of the formed filtration mass used in the process had the tendency to leave the initial rotation axis, disturbing the production process. Ensuring stable cartridge production also required a special spraying head to be developed, generating hot polypropylene fibres using the melt-blown technology. A highly efficient head was required in order to meet the increasing demand for quickly forming filter cartridges. The last element of the developed technology included a special knife for cutting the cartridges to the desired length under conditions of continuous motion of the formed cartridges. Development and coordination of the aforementioned steps of the production process enabled implementation of a fast, continuous and efficient technology of filter cartridges production without waste being generated. Filter cartridges obtained using this technology are less expensive, thus providing a competitive advantage on the market. The production method also enables filter cartridges with desired useful parameters and a production of a full type and range of cartridges to be achieved. The last, but also very important, characteristic of the new technology includes such a modification of the spraying head which ensures zone formation of various fibre types, thus enabling production of several filtration layers with various properties in a single cartridge, ensuring better, combined useful properties of the cartridge, such as improved filtration efficiency and improved contamination absorption.

The invention is presented in several embodiments on the drawing, wherein:

fig. 1 shows schematically a device for repeated production of filter cartridges equipped with a rigid, perforated core,

fig. 2 shows schematically mesh core structures, on which further the actual filtration layer made of polypropylene fibres is applied during the production process, fig. 3 shows schematically the construction and the principle of operation of the core feeding system providing cores to the central shaft,

fig. 4 shows a system providing core motion along the central shaft,

fig. 5 shows schematically the guide construction,

fig. 6. shows schematically the stabilising roller system

Example

The device used in repeated production of filter cartridges equipped with a rigid, perforated core has been schematically presented in fig.1. The central shaft (1) is driven by the engine (2) and rotates with a speed adequate for collection of the produced polypropylene fibres and for formation of filtration layer of the filter cartridge. Along a section of the central shaft, close to the engine (2) a system (3) feeding new cores and locating them on the rotating central shaft is provided. The new core moves along the central shaft towards the spraying head (4) thanks to the system (5) which ensures core motion along the central shaft, towards the spraying head. Said system moves the cores to the guide (6) which supports the cores and provides some resistance during core motion, and at the same time acts as a bearing for the rotating central shaft. A formation zone of the fibrous layer of filter cartridges is located behind the guide. In this area, fibres leaving the spraying head are wound onto rotating cores, join one another, harden and form a porous filtrating layer of the filter cartridge. The cartridge reaches its final thickness behind the filtration layer formation zone and enters between the stabilising rollers (7). The presence of the rollers here prevents the rotating central shaft, loaded with the mass of the formed filter cartridges, from flailing motion. A circular rotating knife (8) with a sharp edge, driven by an engine (9), is located behind the stabilising rollers. The knife is installed on a guide (10) moving back and forth along the axis of the central shaft with a speed equal to the speed of the filter cartridge being formed on the central shaft. If the guide is located at the smallest distance from the spraying head, the knife moves towards the central shaft and cuts the fibrous layer of the filter to its core, where edges of two adjacent cores abut each other. The cut off part of the filter comprising a single filter cartridge falls into a container collecting ready filter cartridges. Individual cartridges of production installation for filter cartridges are presented in the following figures. Fig. 2 schematically presents mesh core structures, on which the actual filtration layer made of polypropylene fibres is applied during the production process. The core is made of two identical, semi-cylindrical cartridges presented in fig.2.a having installation clips (1) located along their longitudinal edges. Assembly of two such halves leads to a single core with the joint resistance being adequate for the core to be used further in the production process of filter cartridges. Fig.2. c presents a cross-section through a core made of two halves.

Fig. 3 schematically presents the design and the principle of operation of the core feeding system providing cores to the central shaft. Core halves are collected from two feeders (1) and (2) by grippers (3) and (4) which then approach the central shaft (5) and are clipped onto the shaft. Thickness of the central shaft is smaller along the section where the cores are applied onto it in order not to cause excessive friction when core halves are joined. Once the core halves are joined along the clips, the jaws (6) with the grippers are moved away and under the feeders in order to pick up another pair of core halves. Operation of the core feeding system is coordinated with operation of the system moving cores along the central shaft and is repeated cyclically.

The system moving cores along the central shaft is presented schematically on fig.4. It includes a motor-driven set of chain wheels (1) with two parallel chains, to which transverse steel profiles are attached (2). Distance between the profiles at the chain corresponds to the length of the moved core. Application of a new core on the central shaft is performed by the core system feeding applying cores onto the central shaft, when space on the central shaft is freed after the previous core is moved towards the guide.

Guide construction is schematically presented on Fig.5. The guide is placed in a stand, not shown on fig.5. and used to stabilise the central shaft rotation, at the same time enabling motion of empty cores along the shaft, to the zone located under the head, where application of the filtration layer onto the cores takes place. The guide is made of two cylinders (1) and (2) with the inner cylinder (2) installed on a bushing in order to ensure its free rotation inside the stationary outer cylinder (1). The inner cylinder has spring-type bosses (3), at least one and preferably three or four bosses located uniformly along the internal circumference of the internal cylinder. If a new core is moved along the central shaft to the guide, the bosses (3) hide inside the inner cylinder and the springs located underneath the bosses press the core against the central shaft. Pressing the bosses against the core enables the rotation motion of the central shaft to be transferred to the inner cylinder rotating inside the outer cylinder, together with the central shaft and with the core. The core moves along the central shaft inside the guide thanks to the force exerted by the system moving the cores along the central shaft, or by the preceding core.

The spraying head used for blowing the molten polypropylene and for polymer fibre formation ejects a stream of hot fibres which wind up around the core rotating under the head. In order to enable fast production of filter cartridges, the head has adequately high efficiency and significant width of the spraying head. In order to enable production of filters with various fibre layers in this system, e.g. thinner fibres located closer to the core and thicker fibres located in the outer layer of the filter cartridges, the spraying head is divided into zones generating appropriate fibre types with adequate efficiency. This solution ensures repeated production of filter cartridges with non-uniform structure of the filtration layer. It is also possible to use separate heads generating various fibre types and installed in series before the moving core.

The central shaft which supports the moving and rotating core sections of filter cartridges is no longer needed when the fibre layer applied around the core takes over the function supporting and connecting individual cores. The central shaft ends in the zone where fibrous layer is formed on the cores. At least three stabilising rollers are provided in order to protect the produced cylindrical filter rotating around its own axis behind the fibre-forming zone. A diagram presenting location of these rollers is presented on Fig.6. The axes of these rollers are parallel to the axis of the produced filter and may rotate freely, taking over the rotational motion from the abutting filter. A rotating knife on a guide is located behind the stabilising rollers. The guide moves back and forth along the axis of the formed filter cartridge. When the guide is located at the shortest distance away from the head, the rotating knife moves towards the filter, and when the guide is moving together with the formed filter cartridge, the knife is gradually pressed all the way down to the core of the filter cartridge, and thus a single cartridge is cut off. Filter cartridge cutting is coordinated with operation of the core feeding system in such a manner that cutting of a formed filter cartridge takes place where subsequent cores abut each other or at locations being multiples of said cores.

Claims

1. A method for the repeated production of a filter cartridge equipped with a reinforcing mesh core, wherein said method comprises steps of applying cyclic core on a rotating shaft, then moving a new core along the central shaft towards the spraying head in such manner, that core rotating with shaft is continuously moved under the spraying head, and so forming a fibrous layer on the core, then cutting of thus formed filters using a rotating knife.

2. The method according to claim 1, wherein the cores made of two halves equipped with clips on the edges are used.

3. The method according to claim 2, wherein applying said cores onto a rotating shaft is carried with a dedicated system for feeding a new core.

4. The method according to claim 3, wherein the cores applied onto the central shaft are moved towards the spraying head using the core motion system.

5. The method according to claim 4, wherein the core motion system comprises pushing elements located evenly at a distance corresponding to the length of a single core and moving above the core feeding system.

6. The method according to any of the claims 1-5, wherein a guide is used, which presses the core to the shaft, stabilises motion of the central shaft and ensures free rotation of the shaft with the cores, and provides free motion of the cores along the shaft.

7. The method according to any of claims 1-6, wherein forming the filtration layer is carried out with a head producing a uniform fibre type.

8. The method according to any of claims 1-6, wherein forming of the nonuniform filtration structure is carried out with a head which is divided into sectors generating sequentially various fibre types.

9. The method according to any of claims 1-8, wherein forming of the nonuniform filtration structure is carried out with a several different heads located one over another, over the moving cores.

10. The method according to any of claims 1-9, wherein forming of the nonuniform filtration structure is carried out with at least three stabilisers which are abutting the formed filter and rotate around axes parallel to the filter axis or perpendicular to the filter axis.

1 1. The method according to any of claims 1-10, wherein the method comprises the step of cutting off the filter cartridges using a rotating knife moving together with the cut filter.

12. A device for repeated production of filter cartridges equipped with a rigid perforated core, said device consisting of a central shaft (1) driven by an engine (2) and rotating, a system (3) for feeding new cores and applying them onto the central shaft located close to said engine (2), a system (5) for moving the cores along the central shaft (1) towards the spraying head, a system moving the cores towards a guide (6) which holds the cores and acts as a bearing for the rotating central shaft, a fibrous layer formation zone of the filtering cartridge located behind the guide, stabilizing rollers (7) behind which a circular rotating knife (8) with a sharp edge driven by an engine (9) is located, installed on a guide (10) moving back and forth along the central shaft axis.

13. The device according to claim 12, wherein the core consists of two identical, semi-cylindrical cartridges having installation clips (1) located along their longitudinal edges.

14. The device according to claim 12 or 13, wherein along the feeding section of new cores the central shaft has slightly smaller diameter.

15. The device according to any of claims 12-14, wherein the system moving the cores along the central shaft includes a motor-driven system of chain wheels (41) with two parallel chains to which transverse, steel profiles (42) are attached, with the distance between profiles corresponding to the length of the moved core.

16. The device according to any of claims 12-15, wherein the guide is placed in a stand and made of two cylinders (51) and (52) with the inner cylinder (52) installed on a bearing and equipped with spring- type bosses (53) in a number of at least one and preferably three or four located at an equal distance from one another along the internal circumference of the inner cylinder, which hide inside the inner cylinder and the springs located beneath them to press the core against the central shaft.

17. The device according to any of claims 12-16, wherein the spraying head is divided into zones generating appropriate fibre types, or the device is equipped with separate heads for various fibre types, installed in a series above the moving core.

18. The device according to any of claims 12-17, wherein the central shaft is terminated in the formation zone of the fibrous layer on the cores, and at least three stabilising rollers are located behind the fibre formation zone.

19. The device according to claim 18 wherein the stabilising rollers have their axes parallel to the axis of the produced filter and may rotate freely, taking over the rotational motion from the abutting filter.