RU2504952C2 - Method for making filtration element for fluid cleaning and method of fluid cleaning - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: method of making the filtration element comprises feeding polypropylene into extruder proportioner, smelting it to fluid state, feeding fluid polypropylene to extruder aerodynamic nozzle, air feed to said nozzle, extruding at least one thread to be wound so that tubular structure of filtration element is produced with flat inner surface and threaded outer surface with high density of thread winding at ribs of threaded surface and set of channels extending in helical line from outer surface towards inner surface of said tubular structure. Produced filtration element is used in method of fluid cleaning including fitting said filtration element into cleaning chamber of said filtration element, forcing the fluid therein and through set of filtration element channels and discharging said fluid therefrom. Milk or water can be used as said fluid.

EFFECT: higher efficiency and quality of filtration, simplified design.

7 cl, 2 dwg

Description

FIELD OF THE INVENTION

The present invention relates to filter elements for cleaning a fluid and methods for manufacturing said filter elements, more specifically, filter elements for fine cleaning milk, in particular cold milk, and methods for its manufacture are described.

State of the art

A known filtering apparatus for milk purification (see patent RU 2054299, class B01D 24/10, publ. 02.20.1996), comprising a housing with a pipe for supplying the source fluid and drainage of the filtrate, a permeable septum installed in the housing with the formation of an upper and lower sections for placement in them of a granular filter bed, the fraction of which in the upper section exceeds the size of the fraction in the lower section.

The filter element consists of filling solid granules made of aluminum oxides, or titanium, or zirconium, or their alloys with open porosity not exceeding 0.1% of the diameter of the granule.

The disadvantages of this solution are limited to use only with milk, structural complexity, high cost, reduced ability to completely remove bacteriological impurities, which negatively affects the quality of filtration.

The aforementioned filtration apparatus needs preventive disassembly in order to inspect the state of its internal cavities and, if necessary, flush permeable partitions from dirt accumulated over time.

Dismantling is carried out after 2-3 months of operation of the apparatus (after 150-250 filter cycles). The process of disassembling and assembling is quite complicated, requires special qualified training and complicates the operation of the apparatus.

Another known solution is a filter for cleaning liquid media (see patent RU 2242266, class B01D 27/08, publ. 12/20/2004) containing a vertical cylindrical housing with an inlet pipe, outlet pipes and a filter element mounted with an annular gap relative to the housing . In the annular gap, a storage and distribution compartment is made with one or two channels for distributing the liquid. In this case, the compartment is connected to the inlet pipe, and the channel or channels are connected to the body cavity. The storage and distribution compartment and the channel for distributing the liquid are formed by the inner surface of the housing and the vertical guide of a curved profile installed in the housing, bounded above and below by the plates.

A significant drawback in this device is the complex design of the device, which is also expensive and low efficient due to the possibility of accumulation of bacteriological impurities in numerous complex structural elements and their transition to the filtrate. The device is also inconvenient in operation due to the complexity of its assembly and disassembly, and also requires special devices to remove the filter element from the apparatus to be replaced.

The prior art filter element for fine purification of raw milk, made in the form of a tubular cartridge of food-grade polymer material formed by discrete rows of fibers obtained by aerodynamic extrusion with pore sizes decreasing radially from the periphery to the center (see patent RU 53585, cl. B01D 27/08, published May 27, 2006).

A disadvantage of the known device is that it is limited only to the purification of milk, it does not allow to purify milk from fine impurities and the small area of the filter element. Filtering is carried out according to the principle: if the particle is less than the pass-through channel of the filter element, then it is skipped, if more, it is delayed. Such devices purify raw milk only from larger impurities than the milk-fat "ball", finer impurities freely penetrate the filtered raw milk and inseminate it. In addition, the feature of installing such a filter, which consists in installing it as shown in Fig. 1, does not allow the entire area of the filter element to work. The filtering element carries out filtering only in its lower part and is quickly contaminated in it, which negatively affects the quality of cleaning and rationality of use.

The present invention aims to solve the problems of the prior art and allows you to effectively use the filter element and method of its manufacture on an industrial scale and apply it in production.

Disclosure of invention

The present invention describes a method of manufacturing a filter element for cleaning a fluid, including filling polypropylene into an extruder dosing device, melting it to a fluid state, supplying polypropylene in a fluid state to an aerodynamic head of an extruder, supplying air to an extruder head, forming at least one thread, winding said thread with the formation of a tubular surface of at least one threaded surface having a high density of winding threads on the edges of the threaded surface and groups of channels extending from the outer surface to the inner surface of the tubular structure in a spiral inside the tubular structure.

In one embodiment of the above method, a group of channels is formed with a decreasing size in the radial direction from the peripheral to the central region of the tubular structure.

Additionally, a thread with a thickness of 0.005-0.03 mm can be formed.

The present invention also describes a method for cleaning a fluid, comprising installing a filter element in the body of the cleaning chamber, made in the form of a tubular structure, provided with at least one thread made of food-grade polymer material, forming at least one group of thread-shaped surfaces having a high winding density threads on the ribs of the thread-like surface, and a group of channels passing from the outer surface to the inner surface of the tubular structure in a spiral inside the tubular of this design, the flow of fluid into the treatment chamber, the passage of fluid through a group of channels of the filter element and the withdrawal of fluid from the treatment chamber.

In one embodiment, a filter element may be installed having a group of channels with a decreasing size in the radial direction from the peripheral to the central region of the tubular structure.

When implementing the above method, milk may be used as a fluid.

Additionally, cold and / or raw milk may be used.

In yet another embodiment of the present invention, water may be used as a fluid.

The technical result of the present invention is to increase the efficiency of use of the filter element, namely: increasing the area of the filter surface, uniform distribution of the filtered milk on the surface of the filter element, increasing the path of the fluid inside the filter element, increasing the filtration rate when using the filter, simplifying its installation and monitoring .

Brief Description of the Drawings

The present invention and the prior art are illustrated by the following drawings:

Figure 1 - filter element according to patent RU53585 installed in the housing.

Figure 2 - filter element according to the present invention.

A person skilled in the art, using the present description and drawings, can carry out the invention as claimed in the claims.

The implementation of the invention

The present invention describes a filter element for cleaning fluids having a density less than or equal to the density of water, in particular milk, more specifically raw and cold milk, and is a cylinder made of at least one polymeric material. The filter element has fibers or filaments deposited in successive layers on top of each other. The filaments are applied so as to form threaded surfaces that allow uniformly dispersing the filtered fluid over the surface of the filter.

In one embodiment, the filaments are made of food grade polypropylene, in particular polypropylene grade 01030, which is widely used in the art. The named material has high resistance to aggressive environments and allows the formation of filaments with a thickness of about 0.005-0.03 mm at a melting point of about 190-200 ° C.

The filaments are applied by aerodynamic extrusion with a change in the distance between them so that the transmission channels formed between the filaments are large in the peripheral region of the filter element and smaller in the central regions of the filter element.

In one embodiment of the present invention, the thin threads strongly pressed against each other form a skeleton of the filter element and form a skeleton that preserves the geometry of the filter element under the pressure generated during cleaning of the fluid, in particular milk. A threaded surface is formed in places of tight pressing of the threads to each other. The fluid to be cleaned passes through the filter element in areas where the density of the laid threads is lower.

The filter element has a tubular design with a flat inner surface and a threaded outer. A filter element made in accordance with one embodiment of the present invention is shown in FIG. The filter element has a surface similar to a threaded surface and has a lower density of thread winding in region 1 and a higher density in region 2. Accordingly, the fluid to be cleaned passes predominantly through region 1, i.e. where there is a lower density of thread winding.

A threaded surface has a double meaning in this solution. The edges of the surface create the frame of the filter element and give it the necessary rigidity. At the same time, the ribs swirl the flow of the liquid being cleaned and create a “funnel effect”, increasing the path of the liquid being cleaned inside the filter, evenly distributing the fluid on the surface of the filter element and increasing the degree of purification of the fluid. The outer surface of the filter element is threaded, which creates vortex flows during cleaning of the fluid.

The filter element of the present invention increases the flow path of the fluid, for example, in a conventional filter, the fluid runs approximately along the entire height of the filter, and in the present filter, the fluid travels approximately 2 to 3 times longer, which increases the degree of purification of the fluid .

The above arrangement of threads allows you to effectively clean fluids, both from large and small impurities and provides unhindered passage of milk-fat balls through the filter element. The filter element has a non-uniform structure, and in addition, spiral channels for uniform distribution of fluid on the surface of the filter element.

During operation of the filter element, the fluid flows through region 1, because in these places, the density of the winding thread is lower. Accordingly, these areas are polluted first. Reducing the transmission of fluid in the intercostal space leads to the fact that the fluid begins to pass through the ribs of the threaded surface of the filter. In this case, the important point is that the quality of cleaning the fluid is not reduced.

Comparative tests showed that the filter, which has uniform winding of the thread and a flat surface, can clean about 100 liters of water. At the same time, the filter made according to the present invention is able to purify about 130 liters of water, and the degree of water purification is higher than that of the known filters.

The inner diameter of the filter element is selected depending on the design of the treatment chamber, throughput requirements and other parameters. It is preferable to choose an inner diameter from a range of 25, 32, 38 and 50 mm for the unification of the filter elements and the possibility of using them with any fluid treatment plants used today.

The filter length is also selected depending on the design of the treatment chamber, the requirements for throughput and other parameters. It is preferable to select a filter length of 75-500 mm, the most preferred option is a length of 125 mm.

The threaded surface of the filter element preferably has a pitch (distance between the ribs) of 0.3-3 cm. In one embodiment of the present invention, the filter element comprises two, three, four, five or six ribs, similar to the number of visits of threaded parts of general construction. The presence of several threaded surfaces can increase the throughput and uniformity of use of all surfaces of the filter element. To obtain several ribs of a threaded surface, it is preferable to use the appropriate number of threads.

The filter element is made on equipment consisting of an extruder and a carriage. Polypropylene, for example in the form of granules, is placed in the extruder dosing device. By means of a screw mechanism, polypropylene is fed into at least one melting chamber. The melting chambers may consist of a group of steps, preferably two steps. In the first stage, polypropylene is crushed and melted to a viscous state. In the second stage, viscous polypropylene is melted to a fluid state and acquires a plastic-homogeneous mass. A plastic-homogeneous mass by means of a screw mechanism is fed into the aerodynamic head of the extruder.

Heated gas, in particular air, is supplied to the aerodynamic head of the extruder under pressure. By means of heated air, a plastic-homogeneous mass of polypropylene is inflated to form filaments, which are arranged predominantly in a spiral along the tubular structure of the filter element, forming a threaded surface.

Under the influence of the aerodynamic air flow, the thread is twisted into a spiral, first in one direction and then in the opposite direction, so that the formed surface allows the fluid to be evenly distributed over the surface of the filter element.

The thread is wound up in a hot state and when the mandrel, on which the thread is wound, is rotated, the thread itself is pulled, which makes it possible to increase the density of the filter. A wound thread is a spiral wound first in one direction and then in the opposite direction. Thus, the channels for passing the cleaned liquid are made in a spiral inside the tubular structure of the filter element. In the present description and the attached formula, the term "inside" should be understood as between the outer surface of the tubular structure of the filter element and the inner surface.

Winding the thread in the forward and reverse directions creates alternating layers of the filter, which creates channels of a serpentine shape, i.e. the liquid, passing through the above channels, passes simultaneously in a spiral inside the filter, as well as along the serpentine surface. The serpentine surface can be compared with a sinusoid. This embodiment of the channels allows you to increase the path of the fluid several times (approximately 2-4 times).

In one embodiment of the present solution, the thread forms an electret, i.e. a dielectric that maintains a polarized state for a long time after removing an external effect, which led to the polarization (or charging) of this dielectric, and creates a quasiconstant electric field in the surrounding space. Filters made according to the present description are mechanoelectrets, i.e. the electret component in them appears due to mechanical action on the thread, namely due to the tension of the heated thread during its winding on the mandrel.

The described filter element can be used to filter raw milk, cold milk and its other forms, as well as other fluids, such as water, mineral water, juice, wine or other fluids.

Claims (7)

1. A method of manufacturing a filter element for cleaning a fluid, including filling polypropylene into an extruder dispenser, melting the polypropylene to a fluid state, supplying polypropylene in a fluid state to the aerodynamic head of the extruder, supplying air to the head of the extruder, forming at least one thread, winding said thread with the formation of a tubular design of the filter element with a flat inner surface and a threaded outer surface having a high density of winding the thread on the rib a thread-like surface, and a group of channels spiraling from the outer surface to the inner surface of the tubular structure.     2. The method according to claim 1, in which form a group of channels with decreasing size in the radial direction from the peripheral to the Central region of the tubular structure.     3. The method according to claim 1, in which form a thread with a thickness of 0.005 ÷ 0.03 mm     4. A method of cleaning a fluid, including installing in the casing of the treatment chamber a filter element obtained by the method according to claim 1, supplying fluid to the treatment chamber by passing it through a group of channels of the filtering element, and outputting the fluid from the treatment chamber.     5. The method according to claim 4, in which milk is used as the fluid.     6. The method according to claim 5, in which cold and / or raw milk is used.     7. The method according to claim 4, in which water is used as a fluid.

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