CN1085960C - Device for de-watering solid-liquid suspensions - Google Patents

Abstract

The present invention relates to a device used for de-watering solid-liquid suspensions especially cellulose suspensions, wherein suspensions are de-watered between two filter bands (4, 5) and the de-watering area is a wedge shaped area (10, 11) structure. The wedge height is capable of being adjusted by an adjusting part (14'), especially automatically adjusted such as elastically, at its output terminal, especially within the whole band width.

Description

Equipment for dewatering solid-liquid suspensions

The invention relates to a device for dewatering solid-liquid suspensions, especially cellulose suspensions, wherein the suspension is dewatered between two filter belts, and the dewatering zone has a wedge-shaped structure.

The shortcoming of this kind such as the disclosed equipment among the AT 385793 is that this equipment is very limited when setting up the fiber strip that has different sheet weights and achievable dry content along the production belt. The fixed gap at the wedge tail only allows a small, limited range of tablet weights. Among them, when the tablet is heavy, the dry content is high; when the tablet is small, the dry content is low. Especially when encountering materials that are difficult to dehydrate, the excessive pressure at the tail of the wedge makes the materials flow out from the side. Furthermore, excessive pressure in the wedge region can damage the side seals. As the tablet weight increases, the pressure continues to increase and a further consequence is that the driving force required by the machine to overcome the friction is so great that the machine stops.

EP-A-0013458 discloses a device for dewatering with an adjustable wedge. The device also cannot prevent material from flowing out from the side. DE-A-22 46055 disclosed dehydration equipment also has this shortcoming, and in this equipment, be provided with a zone that has the gap such as elastic adjustment at the end of wedge-shaped zone.

It is therefore the object of the present invention to provide a plant which achieves a high dry content even with heavy flakes and at the same time, in particular when dewatering difficult-to-dewater materials, without lateral flow of the material and without The side seals are damaged and the risk of downtime is virtually eliminated.

According to the invention, the solution to the above object is that the wedge height at the outlet-side end, in particular along the entire width, is adjustable, in particular automatically, for example elastically adjustable. Through the adjustable wedge height at the output end, the correct gap can be adjusted for the corresponding tablet weight.

A preferred embodiment of the invention is characterized in that the wedge upper part or the wedge lower part is in particular automatically, for example elastically, adjustable. Through these derivations, the adjustment of the wedge height can be optimally adapted to the other structural conditions of the plant.

An expedient embodiment of the invention is characterized in that the wedge height adjustment is effected by means of one or more pneumatic elements arranged along almost the entire width of the machine, wherein hoses or pneumatic cylinders can be used as pneumatic elements. The wedge height adjustment can also be accomplished by means of one or more hydraulic elements arranged along almost the entire width, bellows or hoses or hydraulic cylinders being used as hydraulic elements. By using pneumatic or hydraulic elements for adjusting the wedge height on the output side, the gap can be adjusted automatically by the resulting pressure. In particular, an embodiment with a hose or bellows extending almost the entire width of the device allows an adaptation of the wedge height to the tablet weight, especially in the case of an uneven distribution caused by the tilting of the wedge. Due to the adaptation of the device to the prevailing conditions, the device retains its functionality even in the event of short-term pressure fluctuations in the material or in the event of thickening or bulging of the filter cake in strips. Therefore, the device has high working reliability.

A suitable embodiment of the invention is characterized in that the wedge top or the wedge bottom is elastically mounted.

An expedient embodiment of the invention is characterized in that the wedge upper part and the wedge lower part are mechanically connected, in particular adjustable, on the feed side. Through the mechanical connection between the wedge upper part and the wedge lower part, on the side facing the feeding device, the thickness of the filter cake formed can be influenced accordingly, and the dewatering of the strip-shaped material to be dewatered can also be controlled correspondingly by the wedge-shaped area. The effect of the length of the corresponding existence.

An expedient embodiment of the invention is characterized in that the maximum or minimum adjustment of the play is limited by stops. By limiting the maximum adjustment, it can ensure that the material is always dehydrated, and at the minimum adjustment, avoid damage to the equipment during idling. The adjustment can be made according to the change of the lateral seal, so that the lateral seal always maintains its sealing function.

An expedient embodiment of the invention is characterized in that the wedge-shaped region extends over the first following, in particular S-shaped, pulling roll, wherein, depending on the arrangement of the pulling rolls, either the upper wedge or the lower wedge extends over the pulling roll And the opposite part extends into the wedge of the filter belt and the pulling roll. With this embodiment, the fiber strip is stabilized between the filter belts until it enters the first S-shaped take-off roll, whereby the fibers are prevented from being pushed back up and thus being squeezed out from the side before the S-shaped take-off roll According to this, it is also possible to prevent the filter cake from expanding afterwards and engage in re-humidification. According to this, first of all, when dehydrating materials that are difficult to dehydrate, such as materials with a low dehydration degree, the production capacity of the dehydrator can be improved.

The main advantage of the present invention is that by changing the wedge pressure, the wedge dehydration can be quickly adapted to the change of the material to be dehydrated. During this period, since the pressure at the tail of the wedge is always the same, the dehydrator is not consistent with the working parameters, such as tablet weight, The change of dehydration degree is automatically adapted, so there is practically no influence on the weight per unit area. In particular, the wedge-shaped area extends over the first S-shaped pulling roller to prevent the material from being extruded from the side at the tail, thus greatly reducing the sensitivity of the dehydrator to changes in the dewatered material. Elastically increasing the opening of the wedge prevents the dehydrator from shutting down when the weight per unit area changes.

In the following, the invention is explained in the form of an exemplary embodiment with the aid of the drawings. The accompanying drawings show:

Figure 1 is a cross-sectional view of a dehydrator with a wedge;

Fig. 2 is a sectional view along the line II-II in Fig. 1;

FIG. 3 is a sectional view along line III-III in FIG. 2 .

FIG. 1 shows a dewatering plant 1 with a wedge-shaped zone 2 and a further dewatering zone, in particular an S-shaped draw zone 3 . In this dewatering plant, an upper screen or filter belt 4 is stretched via an upper deflection roller 6 whose position can be adjusted and then via a deflection roller 7 into a wedge formed by plates 10 and 11 . The second screen or filter belt 5 also enters the wedge via a corresponding deflection roller 8 and a further deflection roller 9 . Material to be dewatered, such as cellulose, is also placed in the wedges via feeder 12 . The upper wedge part 10 and the lower wedge part 11 are mechanically connected on the feed side by means of a spindle 13 and the distance between them is adjustable. After leaving the gap, the filter belts 4 and 5 together with the cellulose strip located between the filter belts 4, 5 run around the S-shaped pulling rollers 21 and 22 and continue dewatering in between. Here, the wedge upper part 10 can be adjusted in height via a pneumatic or hydraulic hose 14 . Compressed air or hydraulic fluid is supplied via a connection 15 . A limit screw 16 is used to define a minimum or maximum adjustment. Slipper 17 is used to bear axial force. In addition, a holder 18 for changing the circulating filter belt is provided. In order to minimize environmental impact, the cover 19 is integrated into the wedge upper part 10 and the filtrate tank 20 is integrated into the wedge lower part 11 . At the end of the wedge, the wedge upper part 10 has an extension 23 extending over the S-shaped pulling roller 21 . According to this, on the one hand the dehydration zone is extended. On the other hand, it prevents the fibers from going back up and from extruding sideways in front of the S-shaped pulling roll.

FIG. 2 shows a sectional view of the adjusting element 14'. The upper abutment bracket 24 and the sides 25, 25' of the abutment can be seen in this figure. The support 24 rests on an upper profile 26 which protrudes beyond a lower profile 27 which is fixedly connected to the lower part 28 of the abutment. A pneumatic or hydraulic hose, which can be supplied with compressed air or hydraulic fluid via a connection 15 , is located between the upper profile 26 and the lower profile 27 . Depending on the pressure in the hose 14 , the guide part 28 fixedly connected to the wedge upper part 10 can be pressed against the upper abutment part 24 . The height of the wedge is adjusted accordingly according to the pressure in the wedge and the pressure in the hose 14 .

Figure 3 shows a sectional view along line III-III in Figure 2 and shows the details of the upper profile 26, the lower profile 27 and the hose 14 between them and shows the connection with the upper support. Part 24 and the corresponding connection of the part 28 connected to the upper part 10 of the wedge.

The present invention is not limited to the embodiment shown in the figure, and can also be used in others, such as a filter belt filter press used in sludge purification and dewatering.

Claims (22)

1. A device for dehydrating solid-liquid suspensions, wherein the suspension is dehydrated between two filter belts, the dehydration zone is an adjustable wedge-shaped zone structure, characterized in that the wedge-shaped zone consists of a top plate Consists of a bottom plate in which the gap at the end of the output side of the wedge-shaped zone extending through the center of the first subsequent S-shaped pulling roll is located relative to the dewatering filter belt And on the other side of the filter belt of the S-shaped pull roller within the wedge between the rollers. 2. Device according to claim 1, characterized in that said gap is adjustable over the entire bandwidth. 3. The apparatus of claim 1, wherein said gap is automatically adjustable. 4. Device according to claim 1, characterized in that the gap is elastically adjustable. 5. The apparatus of claim 1 wherein the wedge upper is adjustable and the wedge bottom is fixed. 6. Apparatus according to claim 5, characterized in that the wedge upper part is automatically adjustable. 7. Device according to claim 6, characterized in that the wedge upper part is elastically adjustable. 8. The apparatus of claim 1, wherein the wedge lower portion is adjustable and the wedge upper portion is fixed. 9. Apparatus according to claim 8, characterized in that the wedge upper part is automatically adjustable. 10. Device according to claim 9, characterized in that the wedge lower part is elastically adjustable. 11. Device according to one of claims 1 to 10, characterized in that the adjustment is effected by means of one or more pneumatic elements arranged along the entire width of the device. 12. Device according to claim 11, characterized in that at least one hose is provided as pneumatic element. 13. The device as claimed in claim 11, characterized in that cylinders are provided as pneumatic elements. 14. Apparatus according to one of claims 1 to 10, characterized in that the adjustment is effected by means of one or more hydraulic elements arranged along the entire width of the apparatus. 15. The device as claimed in claim 14, characterized in that at least one bellows or hose is provided as hydraulic element. 16. Device according to claim 14, characterized in that hydraulic cylinders are provided as hydraulic elements. 17. Device according to claim 1, characterized in that the wedge upper part or the wedge lower part is elastically supported. 18. Apparatus according to claim 1, characterized in that the wedge upper part and the wedge lower part are mechanically connected on the feed side. 19. Apparatus according to claim 18, characterized in that the wedge upper part and the wedge lower part are adjustably connected. 20. The device as claimed in claim 1, characterized in that the maximum or minimum adjustment of the play is limited by stops. 21. The apparatus according to claim 1, characterized in that the upper part of the wedge extends over the take-off roller and the lower part of the wedge extends into the wedge between the filter belt and the take-off roller. 22. The apparatus of claim 1, wherein the lower portion of the wedge extends over the pulling roller.