Patent Description:
Filter presses for separating solid components from liquid components of a slurry are known e.g. from <CIT> or <CIT>. In such filter presses the filters may be horizontally arranged as disclosed in <CIT> or may be vertically arranged as disclosed in <CIT>. Further, such filter presses may have a flexible filter membrane such as a continuous belt, as disclosed in <CIT> or have flexible filter membranes arranged in in each filter frame as disclosed in <CIT>.

Common for both vertically arranged filter presses and horizontally arranged filter presses is that the filter press comprises a head member, a plurality of filter plates (arranged with a flexible filter membrane continuous belt or flexible filter membranes arranged in each filter plate), and a movable tail member, all arranged in a filter press frame. Such filter presses further has an actuator for opening and closing of the filter press, thus, to pull the filter plates apart or to push the filter plates together. Such actuators may comprise hydraulic cylinders acting upon the movable tail member, or an electric motor for mechanically transmitting the opening movement and closing movement of the movable tail member and thereby opening or closing the filter press.

Further, such filter presses have an arrangement for locking and pressing the filter plates tight together before pumping the slurry into the filter press for processing. Such locking and pressing arrangement may comprise for example two or four hydraulic cylinders, either arranged within or separate from the opening and closing actuator cylinders as disclosed above and may be arranged to push the movable tail member even further towards the head member.

An object of the disclosure is to provide an improved and simplified locking arrangement for a filter press.

According to a first aspect of the disclosure, this and other objects are achieved, in full or at least in part, by a filter press comprising a stationary frame, in which a head member, a movable tail member, an actuator for opening and closing movement of the filter press, and a plurality of filter plates arranged between the head member and the movable tail member are arranged. The filter press further comprises a locking arrangement for locking the movable tail member with respect to the stationary frame after the closing movement of the movable tail member and the filter plates towards the head member by said actuator, wherein the locking arrangement is arranged to interact with a supporting surface in the stationary frame and a corresponding supporting surface in the movable tail member. According to the disclosure, the locking arrangement comprises at least one locking member having a first wedge-like surface, which at least one locking member is arranged to be movable in a direction generally perpendicular to the opening and closing movement of the filter press, wherein the first wedge-like surface of the at least one locking member is arranged to interact with a corresponding opposite second wedge-like surface, and at least one locking actuator arranged to move the at least one locking member so that the first wedge-like surface interacts with the opposite second wedge-like surface to thereby press the filter plates against each other, and wherein said corresponding opposite second wedge-like surface is arranged in any one of the supporting surfaces of the stationary frame or the movable tail member, respectively, or wherein the locking arrangement further comprises at least one loading member comprising the opposite second wedge-like surface, which at least one loading member is arranged to be movable in a direction perpendicular to the opening and closing movement of the filter press, and wherein at least one loading actuator is arranged to move the at least one loading member so that the opposite second wedge-like surface of the at least one loading member interacts with the first wedge-like surface of the at least one locking member.

According to this first aspect an improved and simplified locking arrangement is provided, which while providing substantial locking forces will not consume any energy during slurry processing. Wedge-like, or tapered surfaces, constitute very effective machine elements which can provide substantial forces in directions perpendicular to the insertion direction, i.e. it provides great mechanical advantage. This applies in particular to wedges having a limited height vs its length. Further, the locking arrangement may provide sealing of the filter plates without using active hydraulic forces during the filtering process. Thus, while the actuator for opening and closing movement of the filter press pushes the movable tail member and the plurality of filter plates towards the head member upon closing, the locking arrangement will take over the responsibility of pressing the movable tail member and the plurality filter plates towards the head member, and the actuator for opening and closing of the filter press do no longer have exercise active hydraulic forces to keep movable tail member and the plurality of filter plates tight towards the head member.

Even further, the locking arrangement according to the disclosure provides an adjustable sealing upon wear of the filter plates. Thus, when the plurality of filter plates have become worn, the filter plates either have to be exchanged or have to be pressed even further together to ensure sealing between the movable head member, the plurality of filter plates, and the head member. With a locking arrangement according to the present disclosure, the at least one locking member may be moved by the at least one locking actuator even further in the direction perpendicular to the opening and closing movement of the filter press, and this further movement will, when the first wedge-like surface interacts with the opposite second wedge-like surface, urge the movable tail member and the plurality of filter plates even further against the head member, and the filter press will become sealed. Further, it is also possible to monitor and predict the ageing of the sealing by comparing the positioning of the at least one locking member.

According to one embodiment, the supporting surfaces are arranged in openings of the stationary frame and the movable tail member, respectively.

According to one embodiment, the at least one locking member and the at least one locking actuator are arranged in the stationary frame of the filter press.

According to another embodiment, the at least one locking member and the at least one locking actuator are arranged in the movable tail member.

According to one embodiment, the locking actuator and/or the loading actuator are hydraulic, pneumatic, or electrically driven.

According to one embodiment, the first wedge-like surfaces and the opposite second wedge-like surfaces have structural engaging surfaces to prevent relative lateral movement between the first wedge-like surface and the opposite second wedge-like surface.

According to one embodiment, the first wedge-like surfaces and the opposite second wedge-like surfaces have structural engaging surfaces in form of corresponding tongue and groove shapes.

According to one embodiment, the first wedge-like surfaces and the opposite second wedge-like surfaces have friction enhancing surfaces.

With such an arrangement, the locking arrangement will provide sealing of the filter plates without using active actuator forces during the filtering process. Should the actuators for the locking and/or loading members be hydraulic cylinders, such an arrangement will ensure that no leakage of hydraulic fluid may contaminate the slurry processing during the slurry processing.

According to one embodiment, the locking arrangement comprises at least one pair of locking members and loading members.

According to one embodiment, the locking arrangement comprises at least two pairs of locking members and loading members.

According to one embodiment, the locking arrangement comprises at least three pairs of locking members and loading members.

According to one embodiment, the filter press has vertically arranged filter plates, and according to another embodiment, the filter press has horizontally arranged filter plates.

According to one embodiment, the flexible filter membrane is arranged as a continuous web around the filter plates, and in one embodiment a flexible filter membrane is arranged in each filter plate.

According to one embodiment, the actuator for opening and closing movement of the filter press may be one or more hydraulic cylinders, or one or more mechanically actuators comprising an electric motor.

Other objectives, features and advantages of the present disclosure will appear from the following detailed disclosure, from the attached claims, as well as from the drawings. It is noted that the disclosure relates to all possible combinations of features.

All references to "a/an/the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise.

As used herein, the term "comprising", and variations of that term are not intended to exclude other additives, components, integers, or steps.

As used herein, the term "a direction perpendicular to" is to be interpreted as substantially perpendicular. It is clear to the skilled person that minor deviations are possible and allowable within the scope of this term and it should not be interpreted as strictly mathematically perpendicular only.

The disclosure will be described in more detail with reference to the appended schematic drawings, which show an example of a presently preferred embodiment of the disclosure.

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the disclosure to the skilled addressee.

<FIG> show schematical side views of a filter press <NUM> according to one embodiment of the disclosure in an open and closed position, respectively. The filter plates <NUM> are arranged horizontally, and there-in-between a continuous web of flexible filter media <NUM> is arranged. The filter press has a head member <NUM> and a movable tail member <NUM>, and an actuator <NUM> for opening and closing movement of the filter press <NUM>. Also shown schematically is a locking arrangement <NUM>, which will be disclosed in more detail in reference to <FIG> and <FIG>.

<FIG> show schematical side views of a filter press <NUM> according to one embodiment of the disclosure in an open and closed position, respectively. The filter plates <NUM> are arranged vertically, and each plate has flexible filter media arranged therein. The filter press has a head member <NUM> to the left and a movable tail member <NUM> to the right, and an actuator <NUM> for opening and closing movement of the filter press <NUM>. Also shown schematically is a locking arrangement <NUM>, which will be disclosed in more detail in reference to <FIG> and <FIG>.

<FIG> show one embodiment of the locking arrangement <NUM> according to the present disclosure, wherein <FIG> shows the locking arrangement <NUM> in an open position, <FIG> shows the locking arrangement <NUM> in a locked position and <FIG> shows the locking arrangement <NUM> in a locked and sealed position. The locking arrangement <NUM> comprises a locking member <NUM>, a locking actuator <NUM>, a loading member <NUM>, and a loading actuator <NUM>. In the open position, the locking member <NUM> and the loading member <NUM> are withdrawn within the movable tail member <NUM>, and the movable tail head <NUM> is free to move in order to open or to close the filter press as shown with the double-directed arrow on the right side of the movable tail member <NUM> in <FIG>. Within the movable tail member <NUM>, a supporting structure <NUM> may be arranged to be aligned with the supporting surface <NUM> of the opening <NUM> in the movable tail member <NUM> to support the locking member <NUM> and the loading member <NUM>. When the movable tail member <NUM> has moved to a closed position (<FIG>), the locking member <NUM> is moved by the locking actuator <NUM> in a direction perpendicular to the opening and closing movement of the filter press in a linear movement, out through openings <NUM> arranged in a stationary filter press frame <NUM> and opening <NUM> arranged in the movable tail member <NUM>. Thereafter, the loading actuator <NUM> moves the loading member <NUM>, also in a direction perpendicular to the opening and closing movement of the filter press in a linear movement, through the opening <NUM> in the stationary frame and optionally also through the opening <NUM> in the movable tail member <NUM>. It is to be noted that it is not necessary to align the openings <NUM>, <NUM> in a coaxial manner. It is sufficient that the openings <NUM>, <NUM> have enough overlap to allow the locking member <NUM> and the loading member <NUM> to be moved by the locking actuator <NUM> and the loading actuator <NUM> out through openings <NUM>, <NUM>. When the first wedge-like surface <NUM>, and the opposite second wedge-like surface <NUM> interact, the openings <NUM>, <NUM> will move relative to each other.

The locking member <NUM> has a first wedge-like surface <NUM>, and the load member <NUM> has an opposite second wedge-like surface <NUM>. When the loading member <NUM> is moved out through the openings <NUM> in the stationary frame <NUM> and the openings <NUM> in the movable tail member <NUM>, the opposite second wedge-like surface <NUM> will interact with the first wedge-like surface <NUM> of the locking member <NUM>. Further, the locking member <NUM> and the loading member <NUM> will interact with the supporting surfaces the openings <NUM> in the stationary frame <NUM> and the supporting surfaces in the openings <NUM> in the movable tail member <NUM>, and the movable tail member <NUM> will be urged towards the head member <NUM>, and the filter plates <NUM> there-in-between will become pressed and sealed towards each other.

<FIG> show another embodiment of the locking arrangement <NUM> according to the present disclosure, wherein <FIG> show the locking arrangement <NUM> in an open position, <FIG> show the locking arrangement <NUM> in a locked position and <FIG> show the locking arrangement <NUM> in a locked and sealed position.

In this embodiment the locking arrangement <NUM> only comprises a locking member <NUM> having a first wedge-like surface <NUM>, whereas the opposite second wedge-like surface <NUM> is arranged in a supporting surface in the opening <NUM> in the stationary frame <NUM> (as shown in <FIG>). Thus, in this embodiment the locking member <NUM> both locks the movable tail member <NUM> to the stationary frame <NUM>, and as the locking member <NUM> is continued to be moved out further through the openings <NUM> in the stationary frame <NUM> and the opening <NUM> in the movable tail member <NUM>, the first wedge-like surface <NUM> will interact with the opposite second wedge-like surface <NUM> and will urge the movable tail member <NUM> closer to the head member <NUM>, and the filter plates <NUM> (not shown in <FIG>) there-in-between are pressed and sealed towards each other. Also here, a supporting structure <NUM> may be arranged within the movable tail member <NUM> aligned with the supporting surface <NUM> of the opening <NUM> in the movable tail member <NUM> to support the locking member <NUM>.

<FIG> show cross section views of first wedge-like surface <NUM> and the opposite second wedge-like surface <NUM> of the locking member <NUM> and loading member <NUM>, and examples of structural engaging surfaces thereon to prevent relative lateral movement between the first wedge-like surface <NUM> and the opposite second wedge-like surface <NUM>, such opposite second wedge-like surface <NUM> may also, as disclosed above in relation to the embodiment shown in <FIG>, be arranged in a supporting surface of the opening <NUM> in the stationary frame <NUM> of the filter press. <FIG> shows an arrangement with corresponding arced and beveled surfaces along the wedge-like surfaces <NUM>, <NUM>, and <FIG> shows an arrangement with corresponding tongue and groove surfaces along the wedge-like surfaces <NUM>, <NUM>.

The skilled person realises that a number of modifications of the embodiments described herein are possible without departing from the scope of the disclosure, which is defined in the appended claims.

For instance, the at least one locking member and the at least one locking actuator may be arranged in the stationary frame and be arranged to be moved into an opening of the movable tail member, and thereafter into an opening of the stationary frame of the filter press.

Further, the opposite second wedge-like surface may be arranged on a supporting surface on the movable tail member instead of on a supporting surface on the stationary filter press frame (as earlier disclosed in relation to <FIG>), and the locking member may have the first wedge-like surface arranged on the opposite side to what is shown in <FIG> to engage the opposite second wedge-like surface arranged on a supporting surface on the movable tail member.

Claim 1:
A filter press (<NUM>) comprising a stationary frame (<NUM>), in which a head member (<NUM>), a movable tail member (<NUM>), an actuator (<NUM>) for opening and closing movement of the filter press, and a plurality of filter plates (<NUM>) arranged between the head member and the movable tail member are arranged, wherein the filter press further comprises a locking arrangement (<NUM>) for locking the movable tail member (<NUM>) with respect to the stationary frame (<NUM>) after the closing movement of the movable tail member (<NUM>) and the filter plates (<NUM>) towards the head member (<NUM>) by said actuator (<NUM>) wherein the locking arrangement (<NUM>) is arranged to interact with a supporting surface (<NUM>) in the stationary frame (<NUM>) and a corresponding supporting surface (<NUM>) in the movable tail member (<NUM>), characterized in that the locking arrangement comprises
at least one locking member (<NUM>) having a first wedge-like surface (<NUM>), said at least one locking member is arranged to be movable in a direction perpendicular to the opening and closing movement of the filter press, wherein the first wedge-like surface (<NUM>) of the at least one locking member is arranged to interact with a corresponding opposite second wedge-like surface (<NUM>), and
at least one locking actuator (<NUM>) arranged to move the at least one locking member so that the first wedge-like surface (<NUM>) interacts with the opposite second wedge-like surface (<NUM>) to thereby press the filter plates against each other, and
wherein said corresponding opposite second wedge-like surface (<NUM>) is arranged in any one of the supporting surfaces (<NUM>, <NUM>) of the stationary frame (<NUM>) or the movable tail member (<NUM>), respectively, or
wherein the locking arrangement further comprises at least one loading member (<NUM>) comprising the opposite second wedge-like surface (<NUM>), which at least one loading member is arranged to be movable in a direction perpendicular to the opening and closing movement of the filter press, and wherein at least one loading actuator (<NUM>) is arranged to move the at least one loading member so that the opposite second wedge-like surface (<NUM>) of the at least one loading member interacts with the first wedge-like surface (<NUM>) of the at least one locking member (<NUM>).