Ultra-high pressure filter press

Abstract

The application discloses an ultrahigh-pressure filter press and belongs to the technical field of filter presses. The ultrahigh-pressure filter press comprises a filter press frame, a plurality of filter plates are slidably arranged on the filter press frame, filter cloths are embedded on both sides of each filter plate, a filter chamber can be formed by combining adjacent two filter plates, an accumulator is arranged on each filter plate, each filter plate is further provided with an elastic sealing ring which is in communication with the inside of the accumulator and can store working liquid, and a hydraulic cylinder for pushing the filter plates at the end to compress and combine all the filter plates is further arranged on the filter press frame. The ultrahigh-pressure filter press provided by the application abandons the traditional large-area and easily-damaged diaphragm structure, combines the elastic sealing ring and the accumulator to bear the pressure regulating function, the accumulator is pre-charged with an inert gas with a set pressure, the flow of the working liquid in the elastic sealing ring realizes pressure transmission and energy storage, the long-term stable operation of the equipment under normal and ultrahigh-pressure working conditions is ensured, deep dehydration of slurry is realized, and the sealing pressure requirement of different physical property slurries is met.

Description

Technical Field

[0001] This invention belongs to the field of filter press technology, and specifically relates to an ultra-high pressure filter press. Background Technology

[0002] With the rapid development of industries such as mining, chemical production, and wastewater treatment, the demand for deep dewatering of industrial slurries continues to increase, placing higher requirements on the pressing pressure, dewatering efficiency, and filter cake moisture content of filter presses. Among them, the diaphragm filter press is the mainstream equipment. It uses hydraulic cylinders to press the filter plates together, forming filter chambers between the filter plates. Fluid materials enter the filter chambers and are filtered and dewatered through the filter cloth on the filter plates. Water is discharged through the holes in the filter cloth, forming a filter cake in the filter chamber. After the filter plates are pulled apart, the filter cake falls off and enters the subsequent transportation equipment.

[0003] Generally speaking, the pressing pressure of a diaphragm filter press is usually between 1.0 and 2.0 MPa, which is the mainstream range for dewatering municipal sludge and chemical materials. A pressing pressure of ≥5 MPa can be defined as ultra-high pressure. However, conventional diaphragm filter presses cannot be directly upgraded to ultra-high pressure conditions. On the one hand, ultra-high pressure conditions will damage the diaphragm in a short time and make it impossible to operate stably. On the other hand, the sealing performance of the fixed filter chambers between adjacent filter plates is prone to failure under ultra-high pressure conditions, affecting the filtration effect. Moreover, exceeding the critical dewatering pressure will crush the fine particles in the filter cake, which may clog the filter plates. The improvement in the moisture content of the filter cake is negligible, but the energy consumption and equipment wear increase significantly. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-high pressure filter press to achieve stable, safe, and efficient ultra-high pressure deep dewatering, and to solve the technical problems in the prior art such as easy membrane damage, easy seal failure, and high energy consumption and maintenance costs under ultra-high pressure conditions.

[0005] To achieve the above objectives, this invention provides an ultra-high pressure filter press, including a filter press frame. A plurality of filter plates are slidably mounted on the filter press frame. Filter cloth is embedded on both sides of each filter plate. When two adjacent filter plates are combined, they can enclose a filter chamber. Each filter plate is provided with an accumulator, and each filter plate also has an elastic sealing ring on the side closest to the adjacent filter plate. This elastic sealing ring communicates with the interior of the accumulator and is capable of storing working fluid. The elastic sealing ring is used to elastically seal the filter chamber. The filter press frame is also provided with a hydraulic cylinder for pushing the filter plates at their ends to press and merge all the filter plates. When the pressing pressure in the filter chamber is greater than the critical dehydration pressure, the elastic sealing ring contracts and deforms, allowing the working fluid to flow into the accumulator, shrinking the filter chamber and continuing to press the filter cake in the filter chamber.

[0006] In one possible implementation, a sealing seat is provided on the adjacent sides of two adjacent filter plates, and the two sealing seats are a sealing seat one and a sealing seat two. The sealing seat one has an installation ring groove for embedding the elastic sealing ring, and the sealing seat two has a sealing ring protrusion. When two adjacent filter plates are joined together, the sealing ring protrusion can extend into the mounting ring groove and press against the elastic sealing ring to seal the filter chamber.

[0007] In one possible implementation, the side of the sealing ring protruding near the sealing seat has an annular concave surface that can conform to the elastic sealing ring.

[0008] In one possible implementation, both the first sealing seat and the second sealing seat have a pressing lip at their inner edges, which can press the edge of the filter cloth against the filter plate to achieve end face sealing.

[0009] In one possible implementation, the pressing lip has a sealing bevel, and the sealing bevel of the first sealing seat and the sealing bevel of the second sealing seat form a material-blocking sealing area to prevent slurry from seeping into the mounting ring groove.

[0010] In one possible implementation, both the first sealing seat and the second sealing seat can be detachably mounted on the filter plate.

[0011] In one possible implementation, the accumulator is a bladder-type accumulator, which is vertically and detachably disposed on the top surface of the filter plate, and further includes: A connecting pipe, the two ends of which are respectively connected to the accumulator and the elastic sealing ring.

[0012] The significant technical effect of this invention is that the ultra-high pressure filter press abandons the traditional flexible and easily damaged large-area diaphragm structure, and transfers the pressure regulation and volume compensation functions to a combination structure of a circumferentially arranged elastic sealing ring and an accumulator. Specifically, the elastic sealing ring is only set along the outer peripheral edge of the filter chamber, which on the one hand achieves end face sealing of the filter chamber, and on the other hand can adjust the volume of the filter chamber through circumferential deformation to avoid bearing large-area pressing positive pressure; the accumulator, as the core component of pressure buffer, is pre-filled with an inert gas, such as nitrogen, at a preset pressure. It and the elastic sealing ring filled with working fluid inside achieve pressure transmission and energy storage, enabling the equipment to operate stably for a long time under normal or ultra-high pressure conditions, achieving deep dewatering of the slurry.

[0013] During operation: The accumulator is pre-charged with gas to form a pre-charge pressure P0. The pipeline connected to the accumulator is filled with working fluid. If the working pressure does not exceed the pre-charge pressure, it will not enter the accumulator. When the working pressure in the elastic sealing ring is between 0 and P0, the elastic sealing ring maintains its shape, which can complete the closing of the filter plates of the filter press and normal feeding.

[0014] As the hydraulic cylinder gradually increases its pressure, when the working hydraulic pressure inside the elastic sealing ring exceeds P0, working fluid begins to enter the accumulator. According to Boyle's law, "for a fixed quantity of gas in a closed container at constant temperature, the pressure and volume of the gas are inversely proportional." The working fluid entering the accumulator displaces the volume of the pre-charged gas in the accumulator, increasing the pressure inside the accumulator and establishing a new balance with the hydraulic cylinder's clamping force. Simultaneously, the filter cake in the filter chamber is compressed, thus reducing moisture content. Throughout the pressing process, the hydraulic cylinder's oil pressure continuously increases, increasing the clamping force applied to the elastic sealing ring. The working fluid continuously enters the accumulator, reducing the filter chamber thickness. The working hydraulic pressure inside the elastic sealing ring increases, always exceeding the pressure inside the filter chamber, thus maintaining an effective seal.

[0015] In addition, this structure can flexibly change the critical pressure regulation point by adjusting the set pressure of the accumulator, which can adapt to the sealing pressure requirements of slurries with different physical properties and improve the overall adaptability of the machine. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an ultra-high pressure filter press in one embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the intermediate filter plate and accumulator; Figure 3 for Figure 1 Cross-sectional view of the middle filter plate; Figure 4 for Figure 2 A partial sectional view; Figure 5 for Figure 4 Enlarged view of section A.

[0018] In the diagram: 1. Filter press frame; 2. Filter plate; 3. Filter chamber; 4. Accumulator; 5. Elastic sealing ring; 6. Hydraulic cylinder; 7. Sealing seat one; 701. Mounting ring groove; 8. Sealing seat two; 801. Sealing ring protrusion; 802. Annular inner concave surface; 9. Pressing lip; 901. Sealing slope. Detailed Implementation

[0019] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0024] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation", "connection", "linking", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components.

[0026] Conventional diaphragm filter presses cannot be directly applied to ultra-high pressure conditions during normal operation, mainly because the diaphragm is easily damaged. The diaphragm must simultaneously withstand large-area high-pressure alternating loads and material corrosion. In ultra-high pressure environments above 5MPa, the fatigue rate of the diaphragm material increases exponentially, and it will rupture and fail in a short time, making it impossible to maintain stable operation. Furthermore, the sealing performance of rigidly connected adjacent filter plates may also fail under ultra-high pressure conditions, thus affecting the filtration effect. Once the critical dewatering pressure is exceeded, it will also crush the fine particles in the filter cake, clogging the filter plates, with negligible improvement in the moisture content of the filter cake, while significantly increasing energy consumption and equipment wear.

[0027] To resolve the above issues, please refer to [link / reference]. Figures 1-5 The illustration shows an ultra-high pressure filter press according to an embodiment of the present invention, including a filter press frame 1, on which a plurality of filter plates 2 are horizontally slidably arranged. Each filter plate 2 has filter cloth embedded on both sides. When two adjacent filter plates 2 are combined, they can enclose and form a filter chamber 3. The filter press frame 1 is also provided with a hydraulic cylinder 6 for pushing the end filter plates 2 to press and merge all the filter plates 2. The above structure is not the point of invention, but is basically the structure of a traditional horizontal filter press. Therefore, the detailed structure is not described in detail.

[0028] Furthermore, each filter plate 2 is equipped with an accumulator 4, which can be a bladder-type accumulator 4, filled with an inert gas such as nitrogen at a preset pressure. Each filter plate 2 also has an elastic sealing ring 5 on the side near the adjacent filter plate 2, which communicates with the inside of the accumulator 4 and can store the working fluid. That is, one filter chamber 3 corresponds to one accumulator 4. The working fluid can be hydraulic oil or emulsion oil. The hollow elastic sealing ring 5 is set along the outer peripheral edge of the filter plate 2 and is used to elastically seal the end face of the filter chamber 3. This eliminates the need for a large-area diaphragm component that is flexible and easily damaged, enabling the equipment to operate stably under ultra-high pressure conditions for a long time and achieve deep dewatering of the slurry. That is, under ultra-high pressure conditions, when the pressing pressure in the filter chamber 3 is greater than the critical dewatering pressure, the elastic sealing ring 5 contracts and deforms, so that the working fluid flows into the accumulator 4, shrinks the filter chamber 3 and continues to press the filter cake in the filter chamber.

[0029] During operation: The accumulator is pre-charged with gas to form a pre-charge pressure P0. The pipeline connected to the accumulator 4 is filled with working fluid. If the working pressure does not exceed the pre-charge pressure, it will not enter the accumulator 4. When the working pressure in the elastic sealing ring 5 is between 0 and P0, the elastic sealing ring 5 maintains its shape, which can complete the closing of the filter plates of the filter press and normal feeding.

[0030] As the hydraulic cylinder 6 gradually increases its pressure, when the working hydraulic pressure in the elastic sealing ring 5 exceeds P0, working fluid begins to enter the accumulator 4. According to Boyle's law, "for a fixed quantity of gas in a closed container at constant temperature, the pressure and volume of the gas are inversely proportional." The working fluid entering the accumulator 4 displaces the volume of the pre-charged gas in the accumulator 4, increasing the pressure inside the accumulator 4 and establishing a new balance with the clamping force of the hydraulic cylinder 6. At the same time, the filter cake in the filter chamber 3 is pressed, thereby reducing the moisture content. Throughout the pressing process, the oil pressure in the hydraulic cylinder 6 continues to increase, increasing the clamping force applied to the elastic sealing ring 5. The working fluid continuously enters the accumulator 4, reducing the thickness of the filter chamber 3. The working hydraulic pressure in the elastic sealing ring 5 increases, always exceeding the pressure inside the filter chamber 3, thus maintaining the effective sealing of the filter chamber 3.

[0031] It is worth mentioning that the accumulator 4 does not require an additional electrical control system or independent control valve group to control the preset pressure. It only needs to be pre-charged with gas as required before leaving the factory to achieve stable operation of the whole machine. This part is not the core invention point of this case, and it only needs to be maintained during factory commissioning, quarterly maintenance, or when the accumulator 4 is naturally depressurized and repressurized. It does not need to be repeatedly adjusted during normal operation, so it will not be elaborated on here.

[0032] Compared with the prior art, this embodiment provides an ultra-high pressure filter press. By abandoning the traditional flexible and easily damaged large-area diaphragm structure, the pressure regulation and volume compensation functions are transferred to the combination structure of the circumferentially arranged elastic sealing ring 5 and accumulator 4. The elastic sealing ring 5 achieves end face sealing of the filter chamber 3 on the one hand, and on the other hand, through circumferential deformation, the accumulator 4 absorbs additional pressure and adjusts the volume of the filter chamber 3, so that the equipment can operate stably under ultra-high pressure conditions for a long time and achieve deep dewatering of the slurry.

[0033] Meanwhile, this structure can flexibly change the critical pressure regulation point by adjusting the set pressure of the accumulator 4, which can adapt to the sealing pressure requirements of slurries with different physical properties and improve the overall adaptability of the machine.

[0034] Regarding the reasons for the failure of the filter chamber 3 seal, the traditional method often uses a solid rubber sealing ring that is basically non-deformable. Its sealing pressure is entirely determined by the clamping force when the filter plate is closed, and it cannot dynamically adapt to the material pressure in the filter chamber. If the pre-pressure of closing the mold is small, when the slurry pushes the rubber ring outward under ultra-high pressure, gaps are likely to appear on the sealing surface, causing leakage. If the pre-pressure of closing the mold is too large, the rubber ring will be in an over-compressed state for a long time, which will cause permanent plastic deformation prematurely and lose its sealing performance.

[0035] The present invention replaces the solid rubber ring with an elastic sealing ring 5 that can store working fluid internally and is connected to the accumulator 4, forming a dynamically pressure-adjustable sealing structure. That is, by setting the pre-charge pressure of the accumulator, the feed pressure of the filter press is determined, and the accumulator specifications are set so that the pressure-flow curve of the accumulator matches the pressure-volume curve of the filter press. This ensures that the pressure of the working fluid in the elastic sealing ring 5 is always greater than the pressure in the filter chamber 3 throughout the entire pressing process, maintaining sufficient pressure on the sealing surface of the filter plate, and ultimately determining the maximum pressing deformation.

[0036] Please see Figures 3-5 Two sets of separate sealing components, sealing seat 1 7 and sealing seat 2 8, are respectively installed on the end faces of two adjacent filter plates 2. Sealing seat 1 7 has a closed annular mounting groove 701 along the circumference. The elastic sealing ring 5 is embedded and housed inside the mounting groove 701. Sealing seat 2 8 has an integrally formed circumferentially extending protruding sealing ring protrusion 801. After the hydraulic cylinder 6 pushes all the filter plates 2 to press and merge, the sealing ring protrusion 801 extends into the mounting groove 701 of sealing seat 1 7. The outer wall of the sealing ring protrusion 801 directly presses against the elastic sealing ring 5 in the groove. The deformation of the elastic sealing ring 5 under pressure fills the gap between the groove and the protrusion, forming a complete pressure-bearing sealing boundary around the filter chamber 3.

[0037] This embodiment adopts a concave-convex nested alignment structure, which enables the sealing ring protrusion 801 to be automatically centered and positioned when the filter plate 2 is closed, avoiding the problems of elastic sealing ring 5 offset and insufficient local compression. Furthermore, when the elastic sealing ring 5 contracts and deforms under ultra-high pressure, it will not slip radially or come out, thus constraining the range of the sealing ring and structurally preventing high-pressure slurry leakage.

[0038] As a further implementation method, such as Figure 5 As shown, the sealing ring protrusion 801 has an annular concave surface 802 on the side near the sealing seat 7, which can fit into the elastic sealing ring 5. This increases the effective contact area between the sealing ring protrusion 801 and the elastic sealing ring 5, disperses the local contact stress under ultra-high pressure, avoids local stress concentration in the elastic sealing ring 5, prevents tearing and rapid aging and damage, extends the service life of the sealing component, and ensures uniform fitting around the entire circumference, so that the compression of the elastic sealing ring 5 remains consistent. The sealing pressure of the filter chamber 3 is uniform around the entire circumference, and there will be no local gap leakage, thus maintaining stable ultra-high pressure dewatering conditions.

[0039] As a further implementation method, such as Figure 3 As shown, the inner edges of sealing seat 1 7 and sealing seat 2 8 near the inside of the filter chamber 3 extend integrally to form an annular pressing lip 9; after the two filter plates 2 are closed and pressed together, the pressing lips 9 on both sides press against each other, firmly clamping and fixing the edge of the filter cloth laid on the surface of the filter plate 2 between the end face of the filter plate 2 and the lip, forming a continuous end face sealing barrier structure on the innermost side of the filter chamber 3 to achieve end face sealing; at the same time, it can also form a side material blocking seal to prevent the slurry from entering the sealing mating surface and causing sealing failure.

[0040] As a further implementation method, such as Figure 5 As shown in the lower right corner, the pressing lip 9 has a sealing slope 901. The sealing slope 901 of the sealing seat 1 7 and the sealing slope 901 of the sealing seat 2 8 form a material blocking sealing area to prevent slurry from seeping into the installation ring groove 701 and to prevent particles from getting stuck between the elastic sealing ring 5 and the ring groove, causing the sealing ring to not be compressed in place and permanent deformation damage. As a further implementation, both sealing seat 7 and sealing seat 8 can be detachably mounted on the filter plate 2. For example, they can be assembled and fixed to a preset installation position on the end face of the filter plate 2 by detachable connectors such as bolts and clips. Thus, when it is inspected or replaced, a single sealing seat can be disassembled without disassembling the entire filter plate 2; or they can be cast integrally with the filter plate 2.

[0041] Please see Figure 3In some embodiments, the accumulator 4 is detachably mounted on the top surface of the filter plate 2 via a threaded or flanged structure along the vertical direction, and the two ends of the connecting pipe are connected to the accumulator 4 and the elastic sealing ring 5 respectively, so that the connecting pipe, the inner cavity of the accumulator 4, and the inner cavity of the elastic sealing ring 5 together form a closed loop, realizing the mutual transmission of working fluid and pressure between the accumulator 4 and the elastic sealing ring 5. The accumulator 4 is arranged on the outer side of the top of the filter plate 2, completely avoiding the contact area between the filter chamber 3 and the slurry, and does not occupy the sealing assembly space of the end face of the filter plate 2.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of protection of the claims of the present invention.

Claims

1. An ultra-high pressure filter press, comprising a filter press frame (1), wherein a plurality of filter plates (2) are slidably disposed on the filter press frame (1), and filter cloth is embedded on both sides of each filter plate (2), wherein two adjacent filter plates (2) can be combined to form a filter chamber (3), characterized in that, Each of the filter plates (2) is provided with an accumulator (4), and each of the filter plates (2) is also provided with an elastic sealing ring (5) on the side near the adjacent filter plate (2) that communicates with the inside of the accumulator (4) and is capable of storing working fluid. The elastic sealing ring (5) is used to elastically seal the filter chamber (3). The filter press frame (1) is also provided with a hydraulic cylinder (6) for pushing the filter plates (2) at the end to press and merge all the filter plates (2). When the pressing pressure in the filter chamber (3) is greater than the critical dehydration pressure, the elastic sealing ring (5) contracts and deforms to allow the working fluid to flow into the accumulator (4), shrink the filter chamber (3), and continue to press the filter cake in the filter chamber (3).

2. The ultra-high pressure filter press according to claim 1, characterized in that, Sealing seats are provided on adjacent sides of two adjacent filter plates (2), and the two sealing seats are sealing seat one (7) and sealing seat two (8). Sealing seat one (7) has an installation ring groove (701) for embedding the elastic sealing ring (5), and sealing seat two (8) has a sealing ring protrusion (801). When two adjacent filter plates (2) are combined, the sealing ring protrusion (801) can extend into the mounting ring groove (701) and press against the elastic sealing ring (5) to seal the filter chamber (3).

3. The ultra-high pressure filter press according to claim 2, characterized in that, The sealing ring protrusion (801) has an annular concave surface (802) on the side near the sealing seat (7) that can fit into the elastic sealing ring (5).

4. The ultra-high pressure filter press according to claim 2, characterized in that, Both the sealing seat one (7) and the sealing seat two (8) have a pressing lip (9) at their inner edges. The pressing lip (9) can press the edge of the filter cloth onto the filter plate (2) to achieve end face sealing.

5. The ultra-high pressure filter press according to claim 4, characterized in that, The pressing lip (9) has a sealing slope (901). The sealing slope (901) of the sealing seat one (7) and the sealing slope (901) of the sealing seat two (8) form a material blocking sealing area to prevent slurry from seeping into the mounting ring groove (701).

6. The ultra-high pressure filter press according to claim 2, characterized in that, Both the first sealing seat (7) and the second sealing seat (8) can be detachably mounted on the filter plate (2).

7. The ultra-high pressure filter press according to claim 1, characterized in that, The accumulator (4) is a bladder-type accumulator (4), which is detachably mounted vertically on the top surface of the filter plate (2), and further includes: A connecting pipe, the two ends of which are respectively connected to the accumulator (4) and the elastic sealing ring (5).

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