AU7185500A - Filter press and control and regulating device for same - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Maschinenfabrik J. Dieffenbacher GmbH Co.

Actual Inventor(s): Friedrich B Bielfeldt Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: FILTER PRESS AND CONTROL AND REGULATING DEVICE FOR SAME Our Ref: 630633 POF Code: 283870/283888 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- Filter press and control and regulating device for same The invention concerns a filter press to reduce the water contents bound in the capillaries of carbon-containing finely comminuted solids and/or slurries, and a control and regulating device for this filter press.

A filter press of the above type is known from DE-OS 195 35 315 and DE-OS 197 10 708. In industrial applications the pressure chamber of such filter presses is charged in industrial applications with mechanical pressures up to 7.5 MPa and steam pressures above 2.4 MPa at 212 The seals between the walls of the pressure chamber necessary for this purpose are in this case from thermally stable rubber-elastic seals. However, they have not been successful 496 0 0 due to the high abrasive load from the grainy material or suspension to be S* compressed. Consequently, the seals must have a good sealing capacity 15 against abrasive media at high temperatures and be suitable for long-term 0 operation in a pressure chamber having the following geometrical dimensions and physical stress spectrum: length approx. 50 m, width approx. 4 m, stroke of pressure ram within the pressure chamber approx. 0.5 m, 0 velocity of pressure ram approx. 0.1-0.3 m/s, pressure of pressure chamber approx. 7.5 MPa, and Stemperature of pressure chamber up to approx. 220 0

C.

o The above discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

JMN W:SPECIIRN630633.doc SUMMARY OF THE INVENTION The present invention provides a filter press to reduce the water contents bound in the capillaries of carbon-containing, finely comminuted solids and/or slurries, in particular of brown coal, under the effect of thermal energy and pressure on the material to be dehydrated, wherein the thermal energy originating from the superheated steam and the mechanical energy as area pressure on the material to be used can be conveyed to a pressure chamber, while the pressure chamber that can be sealed gas-tight comprises a stationary pressure plate and five hydraulically displaceable walls of the pressure chamber, wherein sealing chambers are provided in all opposite supported surfaces of the walls of the *:pressure chamber, the pressure ram, and the stationary table plate, into which sealing chambers sealing packets made from woven band seals are placed and are plastically deformable therein by means of hydraulic actuating members via pressure plates and actuating wedges.

The present invention also provides a control and regulating device for use in conjunction with the above, whereby due to the form-locking separation of the walls of the pressure chamber, of the pressure ram and of the stationary table plate from the sealing chambers, the pressure is exerted on the sealing ochambers with a control and regulating device via hydraulic lockings and actuating members and the main pressure cylinder independently from the required sealing pressure of the hydraulic actuating members.

The invention, therefore, provides a sealing for a filter press of the type referred to above, the sealing having a good sealing ability even when the material to be compressed is abrasive and at high temperatures, with which the high bendingelastic deformations, occurring due to the thermo-mechanically stressed surroundings can be hydro-mechanically equalised (controlled) inside the sealing chamber and that larger or smaller sealing gaps occurring can be automatically sealed by matching the progress of the process.

JMN W:\SPEClUm630633.doc 4 According to the invention, then, sealing chambers are provided in all opposite supported surfaces of the walls of the pressure chamber, the pressure ram, and the stationary table plate, into which sealing chambers sealing packets made from woven band seals are placed and are plastically deformable therein by means of hydraulic actuating members via pressure plates and actuating wedges.

The choice of the seal in the form of a woven band seal and of the sealing material from woven fabric or carbon fibres that is saturated with oil and is coated with PTFE is of considerable importance for the invention.

.:To enable to use such woven band seals in the application in question, special technical steps and arrangements according to the invention are necessary, so that its good sealing ability at high temperatures with its inelastic consistency tll ~15 could be adapted to suit a spectrum of dynamic loads.

Additionally, the form-locking separation of the walls of the pressure chamber from the sealing chambers, provides that pressure is exerted on the sealing chambers with a control and regulating device via hydraulic lockings and actuating members independently from the required sealing pressure of the hydraulic actuating members. For a geometrically accurate force-locking abutting of the sealing chambers against the walls of the pressure chamber, the temperatures of the walls of the pressure chamber can be controlled to have always the same level relative each other.

Further advantageous measures and developments of the subject matter of the invention become apparent from the sub-claims and the following description with the drawing.

In the drawings: Fig. 1 a front view of the filter press according to the invention, Fig. 2 the outline of the filter press according to Fig. 1 sectioned along B-B, JMN W:\SPECWRN630633doc Fig. 3 the arrangement of a sealing packet between two walls of the pressure chamber along section A-A from Fig. 2, Fig. 4 the arrangement of the sealing packets in the corners I to IV in a detail from Fig. 2, Fig. 5 the arrangement of sealing packets between the walls of the pressure chamber and the pressure ram in a detail from Fig. 2, Fig. 6 a graph illustrating the course of actuating and compressions pressure, and i 9Fig. 7 the arrangement of the sealing packets between the walls of the pressure chamber and the stationary table plate in a detail from Fig.

1.

Fig. 1 shows the filter press 32 according to the invention in a front view with the press frame 13 and the walls 1 and 3 of the longitudinal sides of the pressure chamber continued therein. Also shown is a pressure ram 5, that can be moved up and down and pressure exerted by means of the main pressure cylinders 31, as well stationary table plate 6.

9999o According to Figs. 1 and 2, the pressure chamber 19 to accommodate material to be compressed is formed by the four walls 1, 2, 3 and 4 of the pressure chamber, the stationary table plate 6 and the displaceable pressure ram Vertical pressure of walls 1 to 4 of the pressure chamber against the stop surfaces 17 of the table plate 6 is carried out by the hydraulic actuating members 18.

During the progress of the process, the lateral walls of the pressure chamber 1, 2, 3, and 4, as well as the displaceable pressure ram 5 and the stationary table plate 6, are permanently heated for a thermally controlled corner point position to an operating or process temperature, for example to 212 so that the points of the rectangle I, II, II and IV remain unchanged during the progress of JMN W:SPECIRN63063.doc 6 the process both horizontally and vertically in the geometrically cubic position, as is illustrated in Fig. 2. The heating takes place by a fluid medium, the temperature of which is controlled, through the heating bores 7. As Fig. 4 shows, it is an advantage that the sealing packets 8, constructed in the corner points I to IV according to a sandwich-layer technique, have always a forcelocked contact between the displaceable pressure ram 5 and the stationary walls 3 and 4 of the pressure chamber. The vertical sealing packet 8 on the inside situated short walls 2 and 4 of the pressure chamber remains always in vertical contact with the outside situated longer walls 1 and 3 of the pressure chamber.

The hydraulically actuated walls 1, 2, 3 and 4 of the pressure chamber are subjected to an elastic bending deformation o due to the steam and mechanical pressures acting in the pressure chamber 19 on the material 10 to be compressed. These bending deformations o are absorbed by the hydraulic Sactuation of the walls 1 to 4 of the pressure chamber against the displaceable pressure ram 5 and the stop surfaces 17 and 27 of the stationary table plate 6.

The hydraulic actuating members 12 for the longitudinal sides of the walls 1 and 3 of the pressure chamber are supported on a plurality of the press frame 13 of the press. The hydraulic actuating members 14 for the internal walls 2 and 4 of the pressure chamber are supported by the transverse girders 15, which are connected via the supporting grooves 16 in a form-locking manner with the external walls 1 and 3 of the pressure chamber.

In the case of the non-elastic behaviour of the woven-band profile seal used here without restoring capacity these seals having an increased actuating pressure with a factor of 1.6 x the internal pressure of the pressure chamber have to be acted upon by means of plastic deformation against the seals/chamber walls to reliably prevent leakages on the sealing gaps. The hydraulic actuation of the sealing packets 8 in the sealing chambers 20 and 21 is carried out with the pressure ram JMN W:\SPECNm630633.doc 7 The sealing of the gas pressure outside the region of the material to be compressed of the pressure chamber 19 is shown in Fig. 5 with the arrangement of the sealing chambers 20 and 21. The basic function of the bottom sealing chamber 21 is to wipe the dirt, because it dips into the material 10 to be compressed and has to protect the sealing region of the top sealing chamber 20 protruding above it against abrasion on the inside walls of the walls 1 to 4 of the pressure chamber. The task of the top sealing chamber 20 is the sealing function against the pressure of gas or steam and liquid inside the pressure chamber 19. The top sealing chamber 20 is provided above the bottom sealing chamber 21 at such a height that during the working stroke H the top sealing chamber 20 is always outside of the abrasive region of the internal walls 1 to 4 of the pressure chamber. An advantage of this is long service life, i.e. long service life is expected due to operating in a region with little wear.

During the compression of the woven bands according to Fig. 5, the width x of the sealing chamber for the sealing chambers 20 and 21 remains constant. The S* compression by means of the hydraulic/mechanical lifting mechanisms 22, the hydraulic/mechanical actuating member 23, the pressure plates 11 and the displaceable spacer plates 30 result in a plastic preforming, i.e. a reduction of the height y of the sealing profile. According to Fig. 3 the number and arrangement of the actuating members 23 with the lifting mechanisms 22 is chosen so that uniform compression is assured along the respective lengths of the sealing chambers 20 and 21. According to Fig. 2 in the four corners directly above the corner points I to IV hydraulic/mechanical lifting mechanisms 22' are provided, which can be actuated independently by the lifting mechanisms 22 having, for example, increased actuating pressure.

A further advantage is that a greater deformation results in each corner region, and consequently assists in a leakage-free operation.

JMN W:\SPECIURN630633.doc 8 The vertical sealing of the internal short walls 2 and 4 of the compression chamber against the external, longer walls 1 and 3 of the compression chamber is shown in Fig. 3. Fig. 3 also shows the arrangement of the sealing packets 9 in the sealing chambers 26. By means of an actuating wedge 24 and of the hydraulic adjusting member 25, the sealing packet is plastically compressed and the vertical sealing against the external walls 1 and 3 of the pressure chamber is assured.

By virtue of the above described thermally regulated corner point position, the sealing chamber 26 is always parallel and vertical. The sealing of the walls 1 to 4 of the pressure chamber in the region of the table plate 6 and the arrangement of the pressure chamber 19 with the static sealing function is illustrated in Fig. 7. The plastic deformation of the woven band profile is carried out by hydraulic/mechanical means with the actuating mechanisms 28 and the adjusting members 29.

In an advantageous manner, the changes in the sealing gap are automatically equalised in the x coordinate due to the thermo-mechanical elastic deformations of the stationary table plate 6 by virtue of the plastic adjustment of the seal within the sealing chamber 26.

The compression of the sealing packets 8 and 9 in the sealing chambers 20, 21 .o and 26, that depend on this method, is illustrated in the graph in Fig. 6 and shows the pressure P as a function of the compression travel H to dehydrate the material 10 to be compressed as well as the actuating pressure q for the seals. In particular the required progress of the actuating pressure q with the factor 1.6 x pressure for the sealing packets 8 and 9 is regulated by means of the mechanisms analogously to the pressure P over the pressure travel H. On the return stroke, for example during the steam expansion process, the analogous matching of the progress of the actuating pressure takes place in the same manner. When the pressure ram 5 executes an idle stroke, the actuating pressures are set to zero.

JMN W:SPECNRN683033.doc 9 Due to the optimum regulation of the actuating pressure for the seals depending from the progress of the process, the wear of the seals will be reduced and the service life of the seals, i.e. the service life when used as sealing packets, will be considerably prolonged.

4o JMN W:NSPECNIRN630633.doc

Claims (9)

1. A filter press to reduce the water contents bound in the capillaries of carbon-containing, finely comminuted solids and/or slurries, in particular of brown coal, under the effect of thermal energy and pressure on the material to be dehydrated, wherein the thermal energy originating from the superheated steam and the mechanical energy as area pressure on the material to be used can be conveyed to a pressure chamber, while the pressure chamber that can be sealed gas-tight comprises a stationary pressure plate and five hydraulically displaceable walls of the pressure chamber, wherein sealing chambers are provided in all opposite supported surfaces of the walls of the pressure i.chamber, the pressure ram, and the stationary table plate, into which sealing chambers sealing packets made from woven band seals are placed and are deformable therein by means of hydraulic actuating members via pressure plates and actuating wedges.

2. A filter press according to claim 1, wherein the woven band seals are "sealing cords made from fabric or carbon fibre having a quadratic cross-section and are coated with PTFE as well as saturated with oil. i S"

3. A filter press according to claim 1 or claim 2, wherein the rectangular points of the sealing packets are laid overlapping one another.

4. A filter press according to any one of claims 1 to 3, wherein the individual actuating members for the sealing chambers can be acted upon with different sealing pressure. A control and regulating device for a filter press according to any one of claims 1 to 4, whereby due to the form-locking separation of the walls of the pressure chamber, of the pressure ram and of the stationary table plate from the sealing chambers, the pressure is exerted on the sealing chambers with a control and regulating device via hydraulic lockings and actuating members and the main pressure cylinder independently from the required sealing pressure of the hydraulic actuating members.

JMN W:\SPECI\IRN630633.doc 11

6. A control and regulating device for a filter press according to claim wherein for a geometrically accurate force-locking abutting of the sealing chambers against the walls of the pressure chamber, the pressure ram and the stationary table plate, the temperatures of the walls of the pressure chamber, the pressure ram and the stationary table plate are controlled to always have the same level relative each other.

7. A control and regulating device for a filter press according to claim 5 or claim 6, wherein the sealing pressure on the hydraulic actuating members is regulated depending from the pressure.

A filter press substantially as hereinbefore described with reference to the accompanying drawings.

9. A control and regulating device for a filter press substantially as hereinbefore described with reference to the accompanying drawings. 20 DATED: 27 November, 2000 9 PHILLIPS ORMONDE FITZPATRICK Attorneys For: MASCHINENFABRIK J. DIEFFENBACHER GmbH CO. JMN W:\SPEC\m630633.doc