FR2522527A1 - Filter with horizontal circular filter table attached to rotor - by torque transmission mountings allowing radial movement of table w.r.t. rotor - Google Patents

Abstract

Filter comprises a motor driven rotor turning on a vertical axis and a circular horizontal table fixed on top of the rotor. The attachment of the table to the rotor comprises mountings which ensure torque transmission while the table is permitted limited free displacement w.r.t. the rotor in at least 1 direction, pref. radial to the axis of rotation. The circular table is pref. made up of a number of perforated sector plates, partic. between 30 and 36 in number. Pref. each transmission mounting comprises a male element engaging a female element, one element being attached to the table and the other to the rotor. In particular, the female element is a channel radial to the axis of table rotation and the male element is slidably engaged in the channel. The male element can be a low friction cross-head slide block or roller(s). This is a heavy-duty industrial filter with applications in the chemical industry, e.g. in the mfr. of phosphoric acid. The mounting allows limited relative movement between filter table and rotor which compensates for expansion and similar stresses imposed by excessive temps., loading, prod. swelling etc. Distortion of the table is avoided so that it remains flat and can be efficiently swept free of cake by a conveyor screen.

Description

CARRIER STRUCTURE FOR ROTARY HORIZONTAL TABLE FILTER
The present invention relates to a support structure for a filter with a rotary horizontal table.

 The horizontal table filters generally consist of a support structure driven in regular and continuous rotation by an appropriate device and a filtration table mounted on this structure.

 More specifically, - the support structure generally consists of a crown driven by a motor and radial gussets integral with this crown as well as circumferential gussets, circumferentially spaced and integral with the radial gussets and arranged on either side thereof. This structure can be of mild steel.

 The filtration table is itself composed of several sectors each comprising radial walls, one or more walls forming the bottom, circumferential walls delimiting one or more trapezoidal boxes and an upper wall which consists of a metal sheet pierced with orifices on which is fixed the filter cloth. This table can be made of stainless steel.

 The bottom of each box is connected by conduits to a vacuum circuit which thus allows the evacuation of the filtration liquid which has entered the box through the filter cloth.

 An example of such a filter is given in particular by French patent No. 1 327-693.

 The assembly of the table on the supporting structure is generally carried out by bolting, so that these two elements are completely integral with one another. More specifically, the walls constituting the bottom of the table and which may have the shape of trapezoidal buckets are welded at their periphery to the above-mentioned radial and circumferential walls. On the other hand, the radial walls are mounted so as to come to enclose in pairs, the upper end of the radial gussets of the structure. The walls of the pair concerned are linked together by a first series of bolts and they are also fixed to the corresponding radial gusset by a second series of bolts.

 Furthermore, the circumferential walls of the table delimiting the boxes, are supported and are also bolted to corresponding circumferential gussets of the structure.

 As can be seen, such an assembly and such a design of the structure results in the circumferential radial gussets forming an assembly which comprises, as only connections, at the upper part, only the stainless steel table and at the lower part, the drive crown.

 Such a structure, which is therefore not self-supporting, lacks rigidity and stability. This can lead to drawbacks for the operation of filters, in particular for large filters or when the conditions for implementing the process in which the filter is used become more severe, for example, for high temperatures or tonnages or finally, in the case of use for the filter, of materials with a very high coefficient of expansion.

 These drawbacks are essentially due to a defect in the flatness of the structure which affects the table, which can hinder in particular the extraction of the filter cake. Furthermore, the stresses generated by this deformation can cause accelerated wear of the filter.

 The object of the invention is therefore the production of a supporting structure of increased stability and rigidity in order to ensure a very precise flatness of the filter under the most severe conditions of use.

 For this purpose, the circular support structure of the invention, for the support and the rotation in rotation of a circular horizontal filtration table of a rotary filter, is of the type comprising - a first drive ring engaging motor means and resting on a first raceway - a second internal connecting ring - radial assembly elements, such as gussets, fixed and resting on the first ring and integral at their internal end and by means of fixing the second ring ; and - one or more radially spaced series of circumferential assembly elements, such as gussets, circumferentially spaced, integral with the radial assembly elements and arranged in pairs, on either side thereof; and this structure is charac terized in that it comprises circumferential connecting means between the circumferential elements of a small series and diagonal connecting and bracing means placed between consecutive radial elements.

 Thanks to its construction, the load-bearing structure of the invention, in addition to the precise flatness which it offers, ensures perfect transmission of the driving forces. Finally, it can allow a certain separation of the table from the structure, so as to provide a degree of freedom from one with respect to the other, according to the different constraints to which they may be respectively subjected.

 The invention will be better understood and other characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of examples illustrating several modes of embodiment of the invention and in which - FIG. 1 is a half-section view of a filter comprising a support structure according to the invention - FIG. 2 is a schematic view from above of a first variant of a structure carrier of a filter according to the invention; - Figure 3 is a partial, enlarged top view of the structure of Figure 2 - Figure 4 is a partial sectional view along the AIL axis of Figure 3 - Figure 5 is a partial sectional view along the axis BB of Figure 3 - Figure 6 is a partial sectional view along the axis CC of Figure 3 - Figure 7 is a partial sectional view along the axis DD of Figure 3 - Figure 8 is a schematic top view of a second variant of a support structure of the invention - Figure 9 is a schematic top view of a support structure according to a third variant of the invention.

 FIG. 1 partially shows in section a filter comprising a support structure according to the invention. The center of the filter is located to the right of the figure.

 In this figure 1, it can be seen that the filter firstly comprises a horizontal filtration table 1 made of stainless steel for example.

In a manner known per se, this table can be made up of several sectors, the number of which can vary according to the size of the filter and, for example, between 30 and 36.

 Each of these sectors comprises radial walls 2, one or more walls forming the bottom and circumferential walls 3 which thus delimit one or more boxes or buckets. The boxes are closed upwards by a plate pierced with orifices on which the filter cloth is fixed (not shown).

 We can also see that the table 1 is supported by a structure 100, made of mild steel for example.

 In the particular case of FIG. 1, the filtration table is not bolted to the support structure but it rests there by means of connection means 4.

 Different embodiments of this support structure will now be described. In the description, the terms internal and external will be used to distinguish the elements which are more or less close to the center of the circular structure.

 In general, the structure 100 comprises a first centering ring 101 engaging the driving means and resting on a raceway constituted by rollers and centering rollers 102. On this ring, and by means of soles 104 , 105, rest on their lower end with radial joining elements 103 such as vertical gussets. In addition, the structure comprises a second internal connecting ring 107 which may possibly rest on a second raceway.

 The elements or gussets 103 are integral with the second crown by their internal end and by fixing and possibly stiffening means 108. These means 108 may consist of two horizontal dishes 109 resting on the crown 107 and enclosing the lower end of 11 element 103 also resting on this crown; and two vertical stiffenings 110 enclosing the end of the element 103 and perpendicular to this element and to the flats 109.

 The number of radial gussets depends on the size of the filter and the number of sectors. For example, it can vary between 30 and 36.

 In addition, circumferential assembly elements identified by the general reference 106, such as gussets, are integral with the radial elements and arranged two by two on either side of these elements in radially spaced series a, b, c, d, e.

 According to the invention, and as shown in FIGS. 2 to 9, the structure is provided with circumferential connecting means 111 between the circumferential elements 106 of the same series and with diagonal connecting and bracing means designated by the general reference 112 placed between 103 consecutive radial elements. All the connecting means and the circumferential elements 111 and 106 form a connecting crown 113 which appears in the form of continuous lines in schematic figures 2, 7 and 8 in which, for simplification, no distinction has been made the circumferential elements and connecting means.

 In the case of FIGS. 2, 3 and 8, there are thus five series of circumferential connecting elements 106 connected together by the circumferential connecting means 111 therefore forming five rings 113.

 For FIG. 9, there are only three series of elements 106 connected by the connecting means 111, thus forming three rings 113.

 According to a preferred variant of the invention, the structure comprises two series of diagonal connecting and bracing means 112 a, 112 b. The connecting means 112 a of the first series extend between the first series of circumferential elements 106, starting from the center of the structure and the fixing and stiffening means 108. The connecting means 112 b of the second series extend between the last series of circumferential elements 106 and either the penultimate series of these same elements, as for example in the case of the embodiments of FIGS. 8 and 9, or the series preceding it, as for example, in the case of the embodiments of FIGS. 2 and 3.

 The connection between the radial elements or gusset 103 and the diagonal connection means 112, is made for example, at the intersection of the elements 103 and the circumferential elements 106 or fixing means 108, as regards the connection means from the first series. The three structural elements 103, 112 and 106 or 108, are therefore linked and integral at this location.

 In the case of FIGS. 2 to 8, the diagonal connecting means 112 thus connect diagonally two consecutive radial elements or gussets 103.

 FIG. 9 shows a more particular embodiment in which each diagonal connecting means 112 a of the first series connects a radial element or gusset 103 to the second connecting ring 107, in the middle of the portion of the latter lying between two elements 103. Each element 103 is thus connected to the crown 107 by two connecting means 112.

 Furthermore, the structure may include a certain number of reinforcement arms 114 a, 114 b or 114 c.

 In general, these reinforcing arms are constituted by two consecutive radial elements and a series of at least one pair of diagonal connecting means placed between these radial elements and arranged so that the entire series of said diagonal connecting means occupies most of the interval between the fixing means and the or the last series of circumferential elements.

 These reinforcing arms can be 6 in number for example.

 These arms may be constituted by two consecutive radial elements 103 linked together by a series of diagonal connection means, which may include some of the diagonal connection means 112 a, 112 b already described, and additional means 115, 116, arranged crossed and two by two in the interval between each series of circumferential elements 106 and in the interval between the first series of these elements and the fixing means 108. In particular, in the case of FIG. 8, the connecting means diagonals 112 b, 115 are arranged in the two intervals separating the last three series of circumferential elements. By cons, in the case of Figures 2 and 3, the connecting means 112b, 115 are arranged or extend in the interval between the last series and that preceding the penultimate.

 In the case of the embodiment represented by FIG. 16, the reinforcement arms 114 c comprise the diagonal connecting means 112 a of the first series arranged as indicated previously, then a pair of connecting means 116 arranged in each respective interval between the first and second and second and third series of circumferential elements 106.

These connecting means 116 are each linked to the circumferential connecting means 111, connecting the circumferential elements 106 facing the second series and to a gusset 103.

 Of course, the description of the reinforcing arms which has just been made can be applied to any structure comprising a number of series of circumferential elements different from those of the figures.

 Figures 3 to 7 show more precisely how the assembly of the different elements of the structure can be carried out.

 In general, the connection between the diagonal connecting means and the radial elements can take place at the intersection of these elements and the circumferential elements 106.

 On each gusset 103, five series of circumferential connecting elements 106 a, 106 b, 106 c, 106 d, 106 e are mounted.

 Regarding the first series or internal series, it can be seen from Figure 4, that it is constituted by dishes 106 a. These dishes may have a greater length than those of the rest of the series when they are between two gussets 103 which constitute a reinforcing arm.

 The second series 106b, as can be seen in FIG. 5, is in principle made up of plates except in the reinforcement arms where the circumferential elements are gussets.

 The third and fifth series consist of dishes.

Figure 7 shows for example, the dishes 106 e of the fifth series. As seen in Figure 6, the fourth series consists of gussets 106 d.

 The circumferential connecting means 111 are generally constituted by angles bolted to the circumferential elements or by plates. They are also angles which constitute the diagonal connecting means 112, 115 or 116.

 For each series, the consecutive angles, that is to say placed between three consecutive radial gussets, are arranged obliquely with respect to each other. In general, these angles are bolted to plates 117 fixed in the angle- formed by the radial gussets and the plates, gussets or circumferential stiffenings and perpendicular thereto. In the reinforcing arms, the angles are further mounted on plates 118 at their intersection with another angle.

 Inside the reinforcing arm 114, it is possible to have, between the series 3 and 4, circumferential elements, two oblique crosspieces 119, each connecting the top of an element 106 of the series 4 to the base of an element. 106 of series 3.

 Finally, it should be noted that the supporting structure of the invention applies to any type of filter - comprising a horizontal filtration table, whatever the very constitution of the table. The type of table which has been specifically described has, of course, been given only by way of example and the carrying structure described could also be used independently with another type of table. Similarly, the connection between the table and the structure can be done in any suitable and known manner other than that specifically described.

 Of course, the invention is in no way limited to the embodiments described and shown which have been given only by way of examples. In particular, it includes all the means constituting technical equivalents of the means described, as well as their combinations if these are used in the context of protection as claimed.

Claims (10)

 1) Circular support structure for the support and the rotational drive of a circular horizontal filtration table of a rotary filter of the type comprising - a first drive ring 101 engaging motor means and resting on a first path rolling - a second internal link ring 107; - Radial assembly elements 103, such as gussets, fixed and resting on the first ring and integral, at their internal end and by fixing means 108 of the second ring; and - one or more radially spaced series of circumferential assembly elements 106, such as gussets, circumferentially spaced integral with the radial assembly elements and arranged in pairs, on either side thereof; characterized in that it comprises circumferential connecting means 111 between the circumferential elements 106 of the same series and diagonal connecting and bracing means 112 placed between consecutive radial elements 103.  2) Structure according to claim 1, characterized in that it comprises two series of diagonal connecting means it, 112b and several series of circumferential connecting elements 106, the connecting means 112a of the first series extending between the first series, starting from the center of the structure, of the aforementioned circumferential elements 106 and the fixing means 108, the connecting means 112b of the second series extending between on the one hand, the last series of circumferential elements 106 and on the other hand, the penultimate series of these same elements 106 or the series preceding it.  3) Structure according to claim 2, characterized in that it comprises five series of circumferential connecting elements 106a, 106b, 106c, 106d, 106e interconnected by the aforementioned circumferential connecting means 111.  4) Structure according to claim 3, characterized in that it comprises three series of circumferential connecting elements 106 interconnected by the aforementioned circumferential circumferential connection means 111 and in that the diagonal connection means 112a of the first series connect each radial element 103 to the aforementioned second connecting ring 107.  5) Structure according to claim 3 or 4, characterized in that it comprises reinforcing arms 114a, 114b, 114c constituted by two consecutive radial elements 103 and a series of at least one pair of diagonal connecting means 112a, 112b , 115, 116, placed between these radial elements and arranged so that the entire series of said diagonal connecting means occupies the average part of the interval between the fixing means 108 and the or the last series d circumferential elements 106.  6) Structure according to claim 1, 2 or 3, characterized in that it comprises reinforcing arms 114a, 114b constituted by two consecutive radial elements 103 interconnected by a series of diagonal connecting means 112a, 112b, 115 arranged crossed and two by two in the interval between each series of circumferential elements 106 and in that between the first series of elements 106 and the fixing and stiffening means 108 and either in the two intervals separating the last three series, or the interval between the last and the one preceding the penultimate.  7) Structure according to claim 4, 1 or 2, characterized in that it comprises reinforcing arms 114c constituted by two consecutive radial elements 103 connected together by diagonal connecting means 112a, 112b, 112c arranged in pairs in the interval separating each of the first, second and third series and connecting each of the two radial elements by means of circumferential connection connecting the circumferential elements 106 of the second series.  8) Structure according to any one of claims 5 to 7, characterized in that it comprises six reinforcing arms 114.  9) Structure according to any one of claims 1 to 8, characterized in that the connection between the diagonal connecting means 112, 115, 116 and the radial elements 103 is located at the intersection of the radial elements and the elements circumferential 106.  10) Structure according to any one of claims 1 to 9, characterized in that the aforementioned circumferential connecting means 113 are constituted by angles or plates and in that the diagonal connecting means 112, 115, 116 are constituted by angles.