DE3238783A1 - Filter candle - Google Patents

Abstract

The arrangement of a composite filter candle supporting a filter sock has a rigid metal carrier (48') and a polypropylene support (64') arranged over this. The support has axial support ribs (92), by means of which it is mounted on the carrier and has circumferential ribs (94), outwardly offset from these axial ribs, which circumferential ribs, together with the axial ribs (92) delimit large windows (96). In this manner, an unhindered flow of the filtered medium away from the filter sock is obtained. Knob-like projections (98) provided on the outside of the axial ribs (92) arrange the filter sock in such a manner that at these points a thinner filter cake section is obtained, at which the filter cake easily breaks up on backwashing. <IMAGE>

Description

Filter candle

Description The invention relates to a filter candle according to the preamble of claim 1 Such a filter candle is described in DEGS 78 31 204 In her case, the support body, the support body and the filter sock are each overlaid cylindrical contact surfaces close together. It has now been recognized that the filtering capacity this known filter candle is therefore not yet optimal0 because the one to be filtered Medium only over the effective passage area through the support body and Support body formed unit can pass, which is the sum of the Overlapping areas of the openings in the support body with the openings of the support body results.

Now you can try0 the openings in the support body and to be arranged in the support body in the same grid and with the same geometry; this requires but very high manufacturing costs for these two parts also need these parts are precisely aligned with one another, and this alignment can be carried out during operation the torques and forces acting on the arrangement also by different elastic or plastic deformation under operating conditions or different temperature-related changes in geometry of the support body and support body entirely or are partially lost again.

By the present invention sol near a filter candle according to the The preamble of claim 1 is developed so that the throughput is improved ist0 without laborious coordination and adaptation of the breakout pattern of the support body and filter body to each other is necessary.

This object is achieved according to the invention by a filter candle according to FIG Claim 1.

In the case of the filter candle according to the invention, the provision of knob-shaped elevations either on the outer surface of the support body or on the inner circumferential surface of the support body or on both of these surfaces fluid channels between the outer surface of the support body and the inner surface of the support body, which extend both in the circumferential direction and in the axial direction and flow allow the medium to be filtered in the axial direction and / or in the circumferential direction. This allows the filtered medium to move behind the filter sock after passing through it split the openings in the support body into partial flows and distribute them, that overall a low pressure drop across the filter candle is obtained, since it is practical all openings in the support body can be used.

The inventive design of the filter candle also makes it possible the size, distribution and geometry of the openings in the supporting body and supporting body independently of one another with regard to the mechanical strength required in each case these parts and with a view to a particularly favorable flow behavior on them Optimize breakthroughs. In addition, the openings in the support body the mechanical properties and filter properties of the filter sock material Be designed to take into account.

Advantageous further developments of the invention are set out in the subclaims specified.

With the development of the invention according to claim 2 it is achieved that the support body itself by bending one by punching with the openings provided sheet metal part 0 which can be produced at the in The longitudinal joint is welded together. The nub of the # Plastic-made support body can be relatively easy to extrude of the support body produced with the nub on the outside with regard to a slight detachment of filtered solid particles both by the incoming flow uncleaned medium as well as countercurrent purging is advantageous. The filter sock This is because under working conditions it also has a knobbed surface design so that you can put a filter cake on the filter sock, which varies from place to place Thickness gets. Such filter cakes break particularly under mechanical stress easy.

The development of the invention according to claim 3 is with regard to a particularly low pressure drop across the filter cartridge is an advantage.

An unequal radial dimensioning of the inside and outside lying knob-shaped elevations, as indicated in claim 4, guaranteed on the one hand, a sufficient size of the surface currents of the filtered medium, on the other hand, a sufficiently large variation in thickness in the deposited filter cake. In addition, such a support body can still be easily produced by extrusion.

With the development of the invention according to claim 5 it is achieved that the support body is under the action of torques and forces Can not shift operating conditions relative to the support body. Such shifts, the different directions and / or at different points of the support body can have different amounts, often lead to premature breakage of the support body.

The development of the invention according to claim 6 enables it, select the fastening points from case to case, the support body needs Not to be specially modified at the attachment points.

The development of the invention according to claim 7 represents an additional one Safety measure that prevents the support body inadvertently from Support body slips off.

With the development of the invention according to claim 8 it is achieved that the filter sock starting from the outer surface of the support body is folded over round deflection surfaces to the inner surface of the support body. In order to The filter sock has a long service life even under high axial pressure guaranteed at the clamping point.

The development of the invention according to claim 9 makes it possible under Use of one and the same support ring and clamping ring of different filter socks Thickness to use. The specified training of the clamping ring also brings a Wedge effect at the clamping point of the filter sock as a further advantage.

In the case of a filter candle according to claim 10, the clamping ring has at the same time a sealing function towards the filter sock.

With the development of the invention according to claim 11 it is achieved that the clamping ring also acts as a sealing ring between the filter candle and the candle carrier plate can serve.

This sealing function of the clamping ring is specified in claim 12 Choice of material guaranteed particularly well; besides, so are the prime costs of the clamping ring is particularly low.

With the development of the invention according to claim 13 it is achieved that the support body is self-supporting in the direction of the continuous ribs. this makes it possible, behind the corresponding support body areas, at least the support body partially retract radially so that particularly large cross-section In these passages for the filtered medium are obtained between the ribs The filtered medium can pass through essentially laminar and without turbulence because the ribs that go smoothly on the inside of the support body are laminar Enable flow pattern With the development of the invention according to claim 14 it is achieved that the filtered medium flows in the shortest possible way to the candle outlet can.

With the development of the invention according to claim 15 is simple Way a support of the ribs of the support body lying between the rib ends Support points guaranteed. This enables relatively little to be used Ribs containing material.

With the development of the invention according to claim 16, this intermediate support becomes of the ribs along a substantially helical stepped curve.

The development of the invention according to claim 17 is in view on the closest possible alignment of the staircase curve to a helix of Advantage.

The invention is explained below with the aid of exemplary embodiments Referring to the accompanying drawings, these show: FIG 1: an axial section through a filter with an a candle carrier plate attached filter candles; Figures 2a and 2b together: an enlarged axial sectional view a single filter candle according to Figure 1; Figure 3: a double-angled transverse Longitudinal section through a modified support body for a composite filter candle the section line III-III of Figure 4; FIG. 4: an axial section through the support body according to Figure 3 along the section line IV-IV there; Figure 5: a transverse Section through a modified support body for use with the support body according to Figures 3 and 4, sectioned along the line V-V of Figure 6; and figure 6: an axial section through the upper end of the support body according to FIG. 5.

Fig. 1 shows a filter such as is used, for example, for filtering sugar beet extracted sugar juice is used, which has been treated with lime for purification and now contains small lime particles. Such filters are also used for removal of so-called donated solid particles from feed water for steam generator and from other liquids used.

The filter has a pressure vessel 10, which consists of a lower part 12 and a cover 14 consists. These container parts have opposite one another Flanges 16 and 18 to which they are screwed by means of bolts 20.

A candle carrier plate 22 is through between the flanges 16 and 18 O-rings 24 clamped in a sealed manner. It undivided the interior of the pressure vessel 10 into an overburden 260 which is connected to an inlet port 28 an outlet space 302 which is in communication with an outlet connection 32.

A multiplicity of receiving openings 34 is provided in the carrier plate 22 intended for a total of 36 designated filter cartridges.

The filter candles are at the top with one on the bottom the clamping ring 38 resting against the carrier plate 22 something malleable Plastic material provided and have a star-shaped guide body 40, which engages in the associated one of the receiving openings 34. From the guide body 40, a threaded bolt 42 runs away upwards and penetrates one via the receiving opening 34 carried away retaining bracket 44, on the upper side of which one on the threaded bolt 42 running clamping nut 46 is supported.

A lower section 48 'of the pressure vessel 10 is conical, so that the filter cake, which when pressure is applied to the outlet space 30 and Setting a lower pressure in the inlet chamber 26 of the filter socks of the filter candles 36 is detached, under the action of gravity, to a solids outlet nozzle 50 ', from where it can then be withdrawn.

As can be seen from Fig. 2, is on the star-shaped guide body 40 a support body 48 attached, which is made of stainless steel and is provided with a plurality of circular openings 50. To increase the Strength, beads 52 running at intervals in the circumferential direction are impressed.

The lower end of the support body 48 is supported by an end plate 54 locked. This is supported by a welded-on nut 56 and a screw 58 a concavely curved resilient retaining disk 60 with a radially over the lateral surface of the support body 48 protruding horizontal edge flange 62.

The edge flange 62 serves as an axial securing device for one made of polypropylene Support body 64 manufactured by extrusion, which essentially also is hollow cylindrical and in a close clearance fit or a slight interference fit on the Support body 48 is pushed. The support body 64 has ten-free Breakthroughs 660 whose passage area is larger than that of the Breakthroughs 50. The material webs 68 delimiting the openings 66 have knobs 70 and protruding radially outwardly in each case at their center nubs 72 protruding radially inward.

Between the nubby inside of the support body 64 and the smooth The outer surface of the support body 48 is thus obtained both in the circumferential direction Channels 74 as well as axial channels not visible in the drawing.

The support body 64 is formed by a plurality of axially offset self-tapping screws 76, the core diameter of which is adapted to the diameter of an opening 50, secured against rotation fixed on the support body 48.

On the nubby outside of the support body 64 is under operating conditions the inside of a filter sock 78 in a form-fitting manner. The filter sock 58 has thus also a knobbed cylindrical configuration under operating conditions.

The upper end of the filter sock 78 is supported by a support ring 80 placed, which is welded to the upper end of the support body 48. The support ring 80 has a smooth cylindrical outer surface that extends over a rounded edge in the end face of the support ring passes over and over another rounded edge merges smoothly into the inner surface of the support body 48. The end of the filter sock 78 is thus placed around the support ring 80 without any sharp folds.

As can be seen from FIG. 2, the support ring 80 delimits an annular one Chamber 82 into which the upper end of the support body 64 engages.

The clamping ring 38 has a substantially U-shaped cross-sectional profile, wherein the lateral, circumferentially extending clamping surfaces 84, 86, which the end of the filter sock against the inside of the support body 48 or the outside of the support ring 80, are inclined at a small angle to the ring axis, to achieve a clamping effect and clamp filter socks of different thicknesses to be able to.

The inside of the bottom of the plastic injection-molded ring 38 carries circumferentially extending ribs 88, its outside in the circumferential direction extending ribs 90, and in this way the clamping ring 38 can also act as a sealing ring serve between the filter candle 36 and the carrier plate 22.

In operation, the filter sock 78 is in a form-fitting manner on the outside of the support body 64, and the filtered medium flows from the back of the filter sock via the openings 66 either directly or via the channels 74 or corresponding axial channels in the openings 50 of the support body 48 and then from the inside of the support body 48 through the guide body 40 into the outlet space 30. Auf A filter cake collects on the outside of the filter sock over time which has unequal thickness according to the knob configuration of the filter sock.

In order to clean the filter candle 36, it is carried along by the outlet space 30 Pressure is applied so that the filter sock 78 lifts off the support body 64 and is inflated to a smooth cylindrical shape. Be in this inflation produced many cracks in the filter cake due to its nub structure, which is why the filter cake is detached well and completely and in the lower section 48 ' of the pressure vessel 10 falls.

A new filter sock 78 is easily pulled on Slide onto the through the support body 48 and the support body 64 and the support ring 80 unit formed and by folding over the uppermost end portion of the filter sock 78 around the support ring 80. Now the clamping ring 38 is pushed on from above and the same pressed on by hand, and the filter candle 36 obtained in this way is attached to the carrier plate from below 22 mounted.

If a support body 64 has to be exchanged, this can be done after removal of the filter sock 78 simply be done by loosening the screw 58, the Retaining disk 62 removes and unscrews clamping screws 76; now the support body 64 can simply be pulled down axially from the support body 48. A new support body 48 can then simply be assembled in the reverse order of the work steps.

For the sake of clarity, the openings are shown in the drawing 50 only in the cutting plane and in the middle section shown separately of the support body 48 reproduced. It goes without saying that these breakthroughs also arranged distributed over the entire circumference in the remaining sections of the support body are.

The openings 66 are in (in development) a square grid arranged; it goes without saying, however, that other regular ones can be used instead Can use grids, e.g. B. Hexagonal grid In the embodiment shown here each of the material webs 68 delimiting the openings 66 is at its center provided with knobs 70 and 72. This allows the support body 64 from relatively soft plastic material such as polypropylene, since those that occur in operation Powers over a large number of Knobs distributed on the support body 48 should be submitted. If you choose a harder material for the knob body you can you reduce the number of knobs 72 and thus even greater with the same knob height Flow cross-sections between the inside of the support body 64 and the outside of the support body 48 provide.

Figures 3 and 4 show a modified support body 64 ', which a plurality of inwardly projecting ribs evenly distributed in the circumferential direction 92 has. The ribs 92 are by extending in the circumferential direction, under the same axially spaced successive ribs 94 interconnected so that the Ribs 92 and 94 limit windows 96.

As can be seen from FIGS. 3 and 4, the ribs 92 are in its section adjacent to a window 96 with a knob-shaped one on the outside Elevation 98 provided. These elevations can be easily removed at the same time as extrusion of the support body 64 'and take part of the area of the window 96 displaced material.

The elevations 98 in turn facilitate the detachment of a filter cake by a filter sock pulled over the support body 64 ', as already mentioned above for the exemplary embodiment according to FIGS. 1 and 2.

The tips of the ribs 94 are supported on a support body 48 ', which is only indicated schematically in FIG.

Since the ribs 94 the support body 64 in the axial direction self-supporting Give property, you can the distance between the ribs 94 and the support body Choose a relatively large 48 '. There is thus a generously dimensioned, free one Drainage for the filtered medium from windows 96.

Since the support body 64 'is stiffened in the axial direction, enough it turns out if it is only supported at greater intervals in this direction. For this the support body 48 'has a plurality of circular arc-shaped support segments 100, which follow one another offset in the angular direction at an axial distance. In which In the exemplary embodiment under consideration, the support segments 100 each extend over 900 and are on the axial free marginal edges of a continuous support plate 102 as well as two support plates 104off 106 which are welded onto these and are perpendicular to this welded in place. In this way, a staircase-like shape that comes close to a helical line is obtained Support surface for the support body 64 ~.

A threaded bolt is attached to the welded support plates 102 to 106 at the top 42 'welded on, the one for attaching the support body 48' to the candle support plate 22 is used. In addition, a support ring 80 'is welded to the support plates 102 to 106, that for receiving the upper end of the support body indicated only by dashed lines in FIG 64 'and for laying around the upper end of a filter sock not shown in detail serves. The assembly of the support body 64 'on the support body 48', the mounting of a Filter sock and attaching the arrangement thus obtained with the interposition a sealing ring takes place in the same way as in the exemplary embodiment according to the figures 1 and 2, with the only exception that the support body 64§ is not necessarily on the support body 48 'needs to be screwed tight.

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Claims (17)

Claims 1. Filter candle with one on a candle carrier plate attachable cylindrical support body made of metal, in particular steel which in its peripheral wall is provided with openings, with one on the support body arranged cylindrical support body made of plastic, which is in its peripheral wall also has openings, with one arranged above the support body Filter sock and with a clamping ring supported on the Rerzen carrier plate for tightly pressing the free end portion of the filter sock against a rounded one upper support surface of the unit formed by the support body and support body, thereby characterized in that the support body (48) on the support body (64) facing Surface and / or the supporting body (64) on the one facing the supporting body (48) Surface provided with a plurality of discrete, e.g. knob-shaped elevations (72) is. 2. Filter candle according to claim 1, characterized in that the supporting body (64) on both its internal and external surface is provided with knob-shaped elevations (70, 72). 3. Filter candle according to claim 1 or 2, characterized in that the knob-shaped elevations (70, 72) smoothly into the boundary walls of the through openings (66) of the support body (7a) and the surfaces of the through openings (66) delimiting material webs (68) pass over 4. Filter candle according to claim 2 or 3, characterized in that the knob-shaped elevations (72) on the inside of the support body (64) have a height of about 0.5 to 1 mm, while the knob-shaped Elevations (70) on the outside of the support body (64) have a height from about 1 to 2 mm. 5. Filter candle according to # one of claims 1 to 4, characterized in that that the support body (64) has a plurality of axially spaced screws (76) is connected to the support body (48). 6. Filter candle according to claim 5, characterized in that the screws (76) Self-tapping screws with the diameter of the through openings (50) in the support body (48) adapted core diameter. 7. Filter candle according to one of claims 1 to 6, characterized by a retaining disk (56, 58) releasably attached to the lower end of the support body (48) (60), the edge (62) of which protrudes radially beyond the support body (48) and the support body (64> below. 8. Filter candle according to one of claims 2 to 7, characterized in that that the upper end of the support body (48) is connected to an edge-free support ring (80) is, which overlaps the upper end of the support body (64) axially and radially. 9. Filter candle according to claim 8, characterized in that the peripheral wall of the support ring (80) is cylindrical and the clamping ring (38) is two at a small angle to the ring axis employed in the circumferential direction Rlemmflächen (84, 86). 10. Filter candle according to claim 9, characterized in that a The bottom of the clamping ring (38) connecting the clamping surfaces (84, 86) transversely to the ring axis aligned and axially protruding ribs (88) running in the circumferential direction wearing. 11. Filter candle according to claim 10, characterized in that the Outside of the clamping ring base is flat, aligned transversely to the ring axis and carries axially protruding ribs extending in the circumferential direction 12. Filter candle according to claim 10 or 11, characterized in that the clamping ring (38) is made of plastic material or made of rubber. 13. Filter candle according to one of claims 1 to 12, characterized in that that internal elevations of the support body (64 ') as continuous ribs (92) are trained. 14. Filter candle according to claim 13, characterized in that the Ribs (92) run in the axial direction. 15. Filter candle according to claim 13 or 14, characterized in that that the support body (48 ') extends in the circumferential direction and perpendicular to the ribs (92) Has support segments (100). 16. Filter candle according to claim 15, characterized in that the Support body (48 ') has a plurality of rigidly connected, radially aligned support plates (102 to 106), on the radially outer axial marginal edges of which each support segments (100) aligned in a transverse plane are attached0 which are offset from one another in the circumferential direction and in the axial direction. 17. Filter candle according to claim 16, characterized in that the support segments (100) each from one of the support plates (102 to 106) to in the circumferential direction next adjacent ones of the support plates (102 to 906g extend.