Filter system

Abstract

Filter system (1) for filtering liquids, having the following features: a cylindrical filter housing (3) for receiving a clamping device (4) and a filter insert; the clamping device (4) comprising: - an anchor bolt (4.1) with a threaded spindle (4.2); - a clamping nut (4.3) that can be screwed onto it; as well as - a clamping sleeve (4.4) that encloses the threaded spindle (4.2) at least over part of its length, bears against the clamping nut (4.3) with one end and faces the filter insert with its other end and exerts a clamping force on it; and a support device (5) which is fixed to the filter housing (3) and which springs in to absorb the clamping force when the filter insert is tightened; wherein the support device (5) comprises a tension rod (5.1) which is passed through an elongated hole (4.5) in the clamping sleeve (4.4) and is thus displaceable in the axial direction of the clamping sleeve (4.4).

Description

[0001] The invention relates to a filter system for filtering media of any kind, in particular liquids. Such a filter system can be used in any sector. In the industrial sector, applications include water, wastewater, oils, and chemicals, and in the food sector, juices such as fruit juices. Reference is made to document DE 10 2016 214 516 A1.

[0002] Document DE 20 2007 014 617 U1 discloses a closure arrangement for a filter housing, the cover of which has a cylindrical centering section and an adjoining flanged section. A candle holder insert on the upper side of a flanged cylindrical section has a central cup into which a plunger of a screw spindle engages when the filter unit is assembled. The flanged cylindrical section has an annular shoulder on its underside, which is pressed against sealing elements not shown in the drawing. Pressure builds up between the interacting annular shoulders by rotating the screw spindle, whereby the convex plunger engages in the trough-shaped cup and forces the candle holder insert downwards.

[0003] Document DE 878 045 B describes a filter consisting of a closed vessel and individual filter elements inserted into it. A filter assembly is held together by a lower and an upper lid, with pressure exerted by a crossbar whose ends rest on counter-bearings attached to the inner wall of the vessel. Tightening a threaded spindle compresses the individual chambers and simultaneously presses the entire filter assembly against a seal at the lower inlet.

[0004] Common filter systems, depending on the application, include at least one filter plate pack, which comprises multiple filter plates stacked on top of each other. Between two adjacent filter plates is a porous, flat filter element, generally made of a fibrous product such as cellulose. The medium to be filtered contains particles that must be removed and are retained by the filter elements. After a certain period of use, the pores of the filter elements become clogged, or a volume of dirt accumulates between the filter plates, necessitating the replacement of the filter elements.

[0005] In general, a filter system should have the following properties: - high throughput - high discrimination - long operating time - Filtration - Absorption of deposited media such as diatomaceous earth, activated carbon and cellulose within the pollutant load volume - easy replacement of the filter elements

[0006] Known filter systems do not meet these requirements, or only meet them inadequately.

[0007] The invention is based on the objective of creating a filter system in which a filter insert can be fixed in a correct position, can be sealed against a housing, and longitudinal expansions due to thermal material expansion are compensated.

[0008] This problem is solved by a filter system having the features of claim 1.

[0009] The filter assembly of a filter system disclosed herein comprises a cylindrical filter housing that accommodates a filter element of any design. In the case of a plate filter element, the filter plate assembly comprises a plurality of filter plates. The individual filter plate is generally circular. Between two adjacent filter plates, there is generally a porous, planar, ring-shaped filter element.

[0010] Several filter plates with filter elements in between are stacked on top of each other to form a filter plate pack. This filter plate pack is then inserted into a filter housing. With circular filter plates, the filter pack has a cylindrical shape, and the filter housing is correspondingly cylindrical. The circumferential surface of the filter pack is in more or less contact with the inner surface of the filter housing. An annular gap between the circumferential surface of the filter plate pack and the filter housing allows water to flow from the outside in towards the filter plates.

[0011] Due to the operating parameters of a pump, an interplay of the required circulation rate and flow resistances, a differential pressure arises which must be hermetically sealed against a given temperature range.

[0012] A first important aspect is the following: The filter plate pack is compressed axially during the filtration process. This compression is necessary and important. It ensures that the filter packs are sealed and that the filter plates do not float apart during commissioning and the filtration process, thus preventing them from separating and rendering the filter system inoperable. Therefore, compressing the filter plates of a pack is essential. The compression process must be individually adjustable.

[0013] By bending the tension rod under prestress, the tensioning and support device can compensate for changes in length caused by the swelling or shrinking of the filter elements and / or by temperature differences between the filter insert and the filter housing.

[0014] The clamping force of a clamping and support device can be readjusted as needed during a filtration process and / or with the filter housing open to counteract further displacement of the filter medium at the sealing surfaces.

[0015] This is not the case with state-of-the-art filter systems. Due to their design, changes in length cannot be compensated for, or not reliably.

[0016] However, this is a major disadvantage, as leaks can occur during the filtration process, impairing production or damaging the filter elements. The invention addresses this issue.

[0017] The invention is explained in more detail with reference to the drawing. The drawing illustrates the following: Fig. Figure 1 shows a filter system including clamping and support equipment in a perspective view; Fig. 2 shows a filter system according to Fig. 1 with a tensioned clamping and support device; Fig. 3 a sectional view of a clamping and support device; Fig. 4 the clamping and support device in the released state as a perspective view; Fig. 5 Clamping and support device according to Fig. 4 in a tense state; Fig. 6 a sectional view of an alternative embodiment.

[0018] The Fig. 1 and Fig. Figure 2 shows a filter system 1 in longitudinal section. The filter system 1 comprises a cylindrical filter plate assembly 2, consisting of a plurality of circular filter plates 2.1, filter elements 2.2 arranged between each pair of filter plates 2.1, and a clamping plate 2.3 attached to one end face of the filter plate assembly 2. Suitable filter elements 2.2 include filter inserts such as candle, bag, or adsorbent inserts.

[0019] The filter plate package 2 is enclosed by a cylindrical filter housing 3 and can be hermetically separated from the external environment.

[0020] The filter housing 3 can accommodate a clamping and support device 4, 5, whereby, in a clamped state, the individual filter plates 2.1 with the filter elements 2.2 are prevented from floating during a filtration process. Furthermore, the filter plate assembly 2 is fixed in an operating position, sealing the filter elements 2.2 and the filter plates 2.1 against each other. Two filter plates 2.1 form a cavity in which the medium to be filtered circulates. To achieve these properties, a definable contact force is applied to the clamping plate 2.3.

[0021] At the in Fig. 1 and Fig. In the filter system 1 shown in Figure 2, the pores of the filter element 2.2 become clogged with particles of the medium over time, causing the throughput of the filter system 1 to decrease. This means that the filter elements 2.2 must be replaced with new filter elements 2.2 after a certain period of time. This replacement process is also improved by means of the clamping and support device 4, 5 according to the invention.

[0022] The medium to be filtered takes the following path through the filter plate assembly 2: Inlet openings are located around the circumference for introducing the medium to be filtered into the cavity below each filter plate 2.1. Here, the medium reaches the filter elements 2.2, where unwanted particles are retained. The cavity is formed by joining two filter plates 2.1. Depending on the system pressure with which the medium moves through the filter plate assembly 2, this pressure causes the individual filter plates 2.1 to float – i.e., to change their distance from one another. However, this is prevented by the contact force generated by a clamping and support device 4, 5. The filter plates 2.1 comprise a multitude of grooves located in a plurality of channels between adjacent groups of rib segments. The filtrate is collected there and directed to a central bore, from where it is discharged.

[0023] The Fig. Figure 3 shows a front view of the clamping and support device 4, 5. The clamping device 4 comprises a threaded anchor bolt 4.1 with a threaded spindle 4.2, a clamping nut 4.3 that can be screwed onto the spindle, and a clamping sleeve 4.4. The clamping sleeve 4.4 surrounds the threaded spindle 4.2 for at least part of its length. One end of the clamping sleeve 4.4 rests against the clamping nut 4.3, while the other end faces the filter plate assembly 2. When a clamping force is generated by turning the clamping nut 4.3, the clamping sleeve 4.4 rests against the cover 2.3 and thereby transmits the clamping force axially. This essentially fixes the filter element in its position and prevents the individual filter plates 2.1 from floating during the filtration process.

[0024] The support device 5 can be fixed to the filter housing 3 and absorbs the clamping force when the filter plate assembly 2 is clamped. For this purpose, the support device 5 comprises a horizontal clamping rod 5.1, which can be fixed in the filter housing 3 transversely to the clamping direction and diagonally. Its two end caps 5.2 are each supported by a bore 3.1 in the wall 3.2 of the filter housing 3. The clamping rod 5.1 passes through an elongated hole 4.5 in the clamping sleeve 4.4 and is thus axially displaceable within the clamping sleeve 4.4. This configuration is well illustrated by the Fig. 2 is evident.

[0025] The clamping rod 5.1 is preferably made of metal and hermetically sealed at its end caps 5.2 and in the area between them, and encased in a plastic layer. It is also advantageous to manufacture the clamping nut 4.3, the threaded spindle 4.2, and the clamping sleeve 4.4 from plastic. This design also compensates for negative effects caused by thermal expansion and prevents longitudinal expansion.

[0026] One idea is to equip the clamping device 4 with a testing device that measures and / or displays the torque of the clamping nut 4.3 during a clamping operation of the clamping device 4. Similar to a torque wrench, this should indicate how tight the clamping nut 4.3 is and thus how high the clamping force of the clamping sleeve 4.4 is. This application can help protect the chemical-resistant plastic parts from damage caused by excessive torque and ensure a suitable preload for the selected filter element.

[0027] The Fig. 4 and Fig. Figure 5 shows the clamping and support device 4, 5 in a clamped and a released state. The different positions of the clamping nut 4.3 and the clamping sleeve 4.4 in the respective state can be seen.

[0028] An alternative embodiment of the filter system 1 according to the invention is derived from the Fig.Figure 6 shows that in this variant, a support device 5 is mounted inside the filter housing 3, which can be pivoted or rotated in one direction for replacing the filter elements 2.2 or the filter plate assembly 2. This allows the support device 5 to be fixed in a first operating position and released again in a second operating position. The preload that is to act on the filter plate assembly 2 can be generated, for example, by means of a plurality of screws 5.4 arranged on a top side of the support device 5.

[0029] The alternative embodiment would have the advantage that no metal parts inside the filter housing need to be hermetically encased, thus ensuring greater operational reliability with aggressive media. The three basic requirements—namely, fixing the filter assembly in the correct position, sealing by means of preload, and accommodating thermal expansion—can be met to a similar extent by this alternative embodiment. Reference symbol list 1 filter system 2 filter plate pack 2.1 Filter plates 2.2 Filter element 2.3 Chipboard 3 filter housings 3.1 Wall 4 Clamping device 4.1 Anchor bolt 4.2 Threaded spindle 4.3 Clamping nut 4.4 Tension sleeve 4.5 Slotted hole 5 Support device 5.1 Tension rod 5.2 End caps 5.3 Drilling 5.4 Screws

Claims

Filter system (1) for filtering liquids, comprising the following features: a cylindrical filter housing (3) for receiving a clamping device (4) and a filter element; the clamping device (4) comprising: - an anchor bolt (4.1) with a threaded spindle (4.2); - a clamping nut (4.3) screwable onto the spindle; and - a clamping sleeve (4.4) which encloses the threaded spindle (4.2) at least over part of its length, bears against the clamping nut (4.3) with one end and faces the filter element with its other end and exerts a clamping force on the filter element; and a support device (5) which is fixed to the filter housing (3) and which resiliently absorbs the clamping force when the filter element is clamped; wherein the support device (5) comprises a clamping rod (5.1) which passes through an elongated hole (4.5) in the clamping sleeve (4.4) and is thus displaceable in the axial direction of the clamping sleeve (4.4). Filter system (1) according to claim 1, wherein the tension rod (5.1) is arranged in the filter housing (3) transversely to the pressing direction. Filter system (1) according to claim 2, wherein the tension rod is bent under a prestress. Filter system (1) according to one of the two preceding claims, wherein the tension rod (5.1) has two end caps and the two end caps (5.2) are each mounted on a bore (3.1) of a wall (3.2) of the filter housing (3). Filter system (1) according to one of the three preceding claims, wherein a test device is arranged on the clamping device (4) which is configured to measure and / or display a torque of the clamping nut (4.3) during a clamping operation of the clamping device (4). Filter system (1) according to one of the preceding claims, wherein the clamping device (4) and the support device (5) are accommodated in the filter housing (3). Filter system (1) according to one of the preceding claims, wherein the filter insert is a filter plate package (2). Filter system (1) according to the preceding claim, wherein an annular gap is provided between a circumferential surface of the filter plate package (2) and the filter housing (3). Filter system (1) according to one of the two preceding claims, wherein a clamping plate (2.3) is attached to an end face of the filter plate assembly (2), wherein the clamping device (4) is designed such that a clamping force is generated by turning the clamping nut (4.3), the clamping sleeve (4.4) rests on the cover (2.3) and thereby introduces the clamping force in the axial direction. Filter system (1) according to claim 1, wherein the tension rod (5.1) is a horizontal tension rod (5.1) which is arranged in the filter housing (3) transversely to the direction of pressure and can be inserted or removed diagonally, wherein both end caps (5.2) of the tension rod (5.1) are mounted on a wall (3.1) of the filter housing (3).

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