CA2758133A1

CA2758133A1 - A press for dewatering a suspension

Info

Publication number: CA2758133A1
Application number: CA2758133A
Authority: CA
Inventors: Goeran Broettgardh
Original assignee: Andritz Oy
Current assignee: Andritz Oy
Priority date: 2009-04-09
Filing date: 2010-03-23
Publication date: 2010-10-14
Anticipated expiration: 2030-03-23
Also published as: BRPI1010252A2; WO2010116026A1; RU2011145300A; CN102388178A; SE533686C2; JP5662998B2; CA2758133C; CL2011002479A1; CN102388178B; BRPI1010252B1; SE0900479A1; RU2495178C2; JP2012523503A

Abstract

A press (1) comprises a distribution device (2) arranged to receive a liquid suspension of solid biological material and to distribute said suspension horizontally along a dewatering drum (8). A
guide plate (22) and a trough (24) arranged below the dewatering drum (8) are arranged at a distance from the dewatering drum (8) for forming a gap (20) between the dewatering drum (8) on one side and the guide plate (22) and the trough on the other side. A feed channel (18) is arranged to lead the liquid suspension from the distribution device (2) to said gap (20). The guide plate (22) is rotatable around a horizontal shaft (30), said horizontal shaft (30) being arranged at a first end (44) of the guide plate (22), whereby a transfer member (50) is connected to the guide plate (22) at a second end (48) of the guide plate opposite the first end (44) of the plate for adjusting a distance (S) of the guide plate (22) from the dewatering drum (8).

Description

A PRESS FOR DEWATERING A SUSPENSION

Field of technique The present invention relates to a press that comprises a distribution device arranged to receive a liquid suspension of solid biological material and distribute said suspension horizontally by means of a dewatering drum, a .guide plate and a trough.. arranged below the dewatering drum, which =. plate and trough are arranged at a distance from said dewatering drum for forming -a gap between the dewatering drum on one side and the guide plate and the trough on .the other. side, into which gap liquid can. be pressed from the.
suspension. upon operation of the the press- in order to-produce. dewatered.
pulp from the solid biological material, and a feed channel arranged to lead .the liquid suspension from the distribution device to said gap.

The present invention also relates to a method of cleaning a press of the above mentioned type.

Technical background Processes aiming ' at dewatering a liquid suspension of solid biological material often utilize a press wherein water is pressed out of the suspension into a drum, -whereby a relativeley -dry pulp is obtained from the biological material. An example of such a process is .production of papermaking pulp from cellulose fibers, .which process often comprises one or more presses where the pulp is dewatered and possibly washed. That kind of presses that are often referred to as dewatering presses or washing presses, depending on whether the pulp is only dewatered or also.washed, often comprise at least one rotaring drum against which the pulp is pressed. As -the. pulp is pressed against the drum, the water is pressed into the interior of the drum while the dewatered pulp. remains on the outer side of the drum and is- scraped off therefrom for instance by means of a so-called scraper. The pressing of the pulp is effected by means. of .a trough and a guide plate_surrounding the drum.

2 Between the trough and the guide plate, on one side, and the drum on the other side a gap is formed, which converges in the rotating direction of the drum.

During dewatering of a liquid suspension in the above mentioned type of press in. order to produce a dewatered pulp it sometimes happens that the pulp sticks in said gap, in devices feeding the liquid suspension to the press, or in devices discharging the dewatered pulp from the press. In such a case the press has to be stopped and the pulp remaining therein has to be removed. EP1035250 describes a press wherein the lower part of the trough can.be lowered for access to possible pulp therein. Further, the side part of the trough can be tilted outwards and downwards as a. baffle for access to yet another part of the drum.

Summary of the invention An object of the present invention is to provide a press for dewatering a liquid suspension of solid biological material, which press provides' a way of removing material that has stuck inside the press in a simpler way than in prior art technique.

This object is achieved with a press comprising a distribution device arranged to receive a liquid suspension of solid biological material and to distribute the suspension horizontally by means of a dewatering drum, a guide plate and a trough arranged under a dewatering drum, which plate and trough are arranged at a distance from the dewatering drum for forming a gap between the dewatering drum on one side and the guide plate and the trough on the other side, in which gap liquid can be pressed from the suspension during operation of the press for forming a dewatered pulp of the solid biological material, and a feed channel arranged to lead the liquid suspension from the distribution device to said gap, said press being characterized in that the guide plate is rotatable around a horizontal shaft arranged at a first end of the guide plate, whereby a transfer member is connected to the guide plate at a

3 second end of the guide plate opposite the first end of the plate for adjusting a distance of the guide plate from the dewatering drum.

An advantage of this press is that the construction thereof is compact and simple, while providing a simple access to possible pulp that has stuck between the drum and the guide plate, so that the press can quickly be cleaned at possible shut-downs.

According to an embodiment the first end of the guide plate is positioned above the other end of the guide plate, seen in vertical direction. An advantage of this embodiment is that the lower part of the guide plate can be .transfered from the drum,, so that pulp that has stuck between the drum and the guide plate can fall down and out of the gap under gravity, possibly assisted also by some instrument.
According to an embodiment the guide plate is arranged below said feed channel. An advantage of this embodiment is that the pulp is led from the feed channel and downwards towards the guide plate, which reduces the risk of pulp sticking or being squeezed between the guide plate and the drum, and simplifies the removal of the pulp in case that would happen anyway.

Preferably the guide plate has a pressing surface provided for forming, together with the dewatering drum, said gap, whereby the feed channel has a nozzle end arranged to communicate with the upper end of the pressing surface while the press is running. An advantage of this is that during removal of pulp that has stuck in the gap between the guide plate and the drum good access is provided, as the guide plate extends up to the feed channel.
According to an embodiment, a sealing strip is arranged between the upper end of the pressing surface and a lower feed plate comprised in the feed channel. An advantage of this is that good access to the gap between the guide plate and the drum is achieved in combination of only a minor risk of leakage of the liquid suspension during operation of the press.

4 According to an embodiment the guide plate is located at least partly on the same horizontal plane as the distribution device. An advantage of this embodiment is that a compact press is provided.
According to an embodiment the guide plate is located at least partly between the distribution device and the dewatering drum. This embodiment provides a 'highly compact construction, as the distribution device and the guide plate share a common space beside the dewatering drum. Further, no space or very little space is required at the side of the press for the guide plate.
More preferably the central part. of the guide plate is located between the distribution device and the dewatering drum.

According to a preferred embodiment the transfer member is a hydraulically steered transfer member. That kind of transfer members are simple to steer and they provide high force when pressing the pulp in the gap between the drum and the guide plate.

According to a preferred embodiment the transfer member is arranged to operate 'in an essentially horizontal direction. This provides a very compact and flexible embodiment of the transfer member.

Another object of the present invention is to provide a flexible way of cleaning a press for dewatering a liquid suspension of solid biological material.
This object is achieved with a method of cleaning a press for dewatering a liquid suspension of solid biological material, said press comprising a distribution device arranged to receive a liquid suspension of solid biological material and to distribute the suspension horizontally by means of a . dewatering drum, a guide plate and a trough arranged below the dewatering drum, which plate and trough are arranged at a distance from the dewatering drum for forming a gap between the dewatering drum on one side and the guide plate and the trough on the other side, in which gap liquid can be pressed from the suspension during operation of the press for obtaining a dewatered pulp of the solid biological material, and a feed channel arranged to lead the liquid suspension from the distribution device to said gap, which method is characterized in that the guide plate is rotatable around a horizontal

5 shaft that is arranged at a first end of the guide plate, whereby a transfer member is. connected to the guide plate at a second end of the guide plate opposite the first end of the plate for adjusting a distance of the guide plate from the dewatering drum, whereby during the cleaning of the press the second end of the guide plate is transferrred by means of said transfer member in a direction away from the dewatering drum, so that the space between the guide plate and the dewatering drum will be accessible for cleaning.

An advantage of this method is that access to and removal of material that 15. has stuck between the guide plate and the drum becomes very flexible and simple.

Other advantages and characteristics of the invention become obvious from the following description and the appended claims.
Brief description of the drawings In the following, the invention will be described by means of exemplary embodiments and with reference to the appended drawings.
Fig. 1 is a perspective view and illustrates a press for dewatering and possible washing of a fiber suspension according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view and illustrates the press of Fig. 1 along section II-II.
Fig. 3 is a cross-sectional view and illustrates an enlargement of the guide plate of Fig. 1 and 2.
Fig. 4 is a cross-sectional view and illustrates the guide plate of Fig. 3 during operation of the press.

6 PCT/F12010/050225 Fig. 5 is a cross-sectional view and illustrates the guide plate of Fig. 3 at a maintenance state.

Description of preferred embodiments Figures 1 and 2 illustrate schematically a press 1 for dewatering a liguid suspension of cellulose fibers for production of e.g. paper. Figure 1 illustrates the press 1 in perspective view with some parts shown in detail and some covers lifted aside, and Fig. 2 illustrates the press 1 shown along along section II-II of Fig. 1.

The press 1 is, as best illustrated in Fig. 1, provided with a longitudinal first distribution screw 2. The distribution screw 2 has a centrally placed inlet 4 for a liquid suspension of solid biological material in form of cellulose fibers.
The . weight percentage of the cellulose fibers in the liquid suspension is typically 3-15 weight-%. The liquid suspension also includes possible impurities, usually no more than approximately 1 weight-%, and the rest, i.e. 84-96 weight-% is water. An inlet conduit 6 is arranged for introduction of the liquid suspension to the inlet 4 from a source of liquid suspension (not shown). e.g.
from a pulper.

The first distribution screw 2 distributes the liquid suspension received via a point-formed inlet 4, along a first dewatering drum 8. The dewatering drum 8 has a liquid-permeable layer, such as a perforated plate or a filter cloth, which allows the cellulose fibers, in form of dewatered pulp, to remain on the surface of the drum 8 during pressing of the suspension against the outer periphery of the drum 8, while the liquid is pressed into the interior of the drum 8 and led away.

The distribution screw 2 extends essentially along the whole length of the dewatering drum 8, which in practice means that the active length LF of the distribution screw 2, which active length LF is the length along which the distribution screw 2 introduces liquid suspension to the dewatering drum 8,

7 typically approximately 75-120%, more typically 80-110% of the active length LT of the dewatering drum 8, which active length LT is the length along which the dewatering drum 8 receives and presses pulp. It is.understood that in addition to the above described active lengths LF and LT illustrated in Fig.
1, both the distribution screw 2 and the drum 8 have, among others, bearings and end pieces not shown in Fig.-1 that are included in their respective total lengths, but not in the active length, which, as mentioned, is the length along -which the liquid suspension is distributed, respectively pressed to produce a still dryer pulp.
As becomes obvious from Fig. I and 2, the press I is also provided with a second distribution screw 10, a conduit 11 arranged for introducing the liquid suspension to the second distribution screw 10, and a second dewatering drum 12. From Fig. 2 it becomes obvious that the press 1 is essentially symmetrical around its central part. For this reason, mainly the right-hand part of the press 1, as shown in Fig. 2, is described, while it is understood that the left-hand part of the press 1 has an essentially corresponding form, only mirror-inverted.

20, The distribution screw 2 has, as becomes obvious from the detailed enlargement of Fig. 1, a casing 14 inside which a screw 16 is arranged to rotate under operation of the discribution screw 2. Thanks to the screw 16, the central part of which is conical in both directions, seen from the centre of the screw 16, the liquid suspension fed via the point-form inlet 4 is distributed evenly along the active length LT of the dewatering drum 8. A feed channel 18 extends essentially horizontally from the upper part of the feed screw 2, approximately aft 11 o'clock seen along the circumference of the housing 14, towards the dewatering drum 8, as shown in Fig. 2. From Fig. 1 it becomes obvious that the feed channel 18 has an active length LI that is essentially the same as the active length LF of the distribution screw 2, more precisely the lenght LI is usually 80-110% of the length LF.

8 Under operation of the press 1, the liquid suspension is fed via conduit 6 to the inlet 4. The liquid suspension can e.g. come from fiber washing or from a pulper connected to another press that is similar to the press 1 and in process view is located upstream thereof. The suspension is distributed by screw 16 of the distribution screw 2 and led via the feed channel 18 to a gap 20 that is formed between the dewatering drum 8 on one side and a guide plate 22 and a trough 24 on the other side. As becomes obvious from Fig. 2 the gap 20 has, seen from the feed channel 18 and further in the rotational direction R
of the drum 8, a converging width. As a result, liquid will be pressed out from the liquid. suspension and into the drum 8 when the liquid suspension is pressed by the drum 8 first against the guide plate 22 and later the trough 24 in a converging gap 20, whereby the cellulose fibers remaining on the outside of the drum 8 will form a further dewatered pulp of cellulose fibers. The dewatered pulp, with a dry solids content of e.g. 15-55 w-%, more typically 20-50.w-%, is then released from the drum 8, approximately at 9 o'clock seen along the periphery of the drum 8 in accordance with Fig. 2, and transported away by means of a shedder screw 26 for further treatment, such as washing and/or drying.

The press 1 can be provided with one or more washing devices 28, by means of. which washing liquid, such as clean water or filtrate or condensate water from another process stage can be introduced into the pulp while the pulp remains in the gap 20, in order to wash away impurities from the pulp.

During operation of the press 1, pulp can stick in the gap 20. This results in shut-down of the press 1, and the trough 24 has to be lowered vertically downwards, as shown by an arrow N in Fig. 2, for access to the drum 8 so that it can be cleaned of the pulp. In accordance with the present invention and in a way presented in the following in more detail the guide plate 22 can also be lowered in a flexible way.

Fig. 3 illustrates the guide plate 22 according to an embodiment of the present invention in a ready for operation state, i.e. a state when liquid

9 suspension can be introduced into the distribution screw 2. The guide plate 22 is rotatable by means of a horizontal shaft 30. As becomes obvious from Fig. 1 the guide plate 22 extends, seen in a horizontal direction, along essentially the whole active length LT of the drum 8, i.e. the guide plate 22 .5 has an active length LP that is typically 80-120% of the active length LT
of the drum 8. The shaft 30 is bearing-mounted in the press 1 at its respective ends, and can also be bearing-mounted in the press 1 in one or more further positions along the length LP of the guide plate 22.

The guide plate 22 is located, as seen in Fig. 3. at least partly on the same horizontal. level as the distribution screw 2, and the central part C of the guide plate 22 is located between the distribution screw 2 and the dewatering drum 8.

The feed channel 18 has, as best illustrated in Fig. 3, an upper feed plate 32 and a lower feed plate 34. The guide plate 22 has a pressing surface 36 that is provided for, together with the drum 8, forming a gap 20. The upper end 38 of the pressing surface 36 is via a sealing strip 40 in contact with a nozzle part 42 of the lower feed plate 34, at which nozzle part the feed channel 18 discharges into the gap 20. The guide plate 22 has in its upper end 44 a notch 46, in which the horizontal shaft 30 is fixed, e.g. by means of welding.
The guide plate 22 extends from a position on the level of the upper part of the distribution screw 2 to a position below the lower part of the distribution screw 2. At its lower end 48 the guide plate 22 is connected to a hydraulic piston 50. The hydraulic piston 50 is fixed in the press 1 and is, as seen in Fig. 3, arranged under the distribution screw 2. The hydraulic piston 50 is arranged to operate in an essentially horizontal position. As becomes obvious from Fig. 1, a number of hydraulic pistons 50 can be arranged along the length LP of the guide plate 22. The hydraulic pistons 50 can be connected to a source 52 of pressurized hydraulic liquid, shown in Fig. 1. A control unit controls the amount of pressurized hydraulic liquid being introduced to the hydraulic pistons 52 from said source 52, whereby the transition point of the hydraulic pistons 50 in horizontal direction can be adjusted. During adjustment of the transition point of the hydraulic pistons 50, the control unit 54 controls the feed of pressurized hydraulic liquid to the pistons 50 from the source 52 of pressurized hydraulic liquid.

As becomes obvious from Fig. 3, a mechanical arrester 56 is provided on the press in order to limit the horizontal transition point of the hydraulic piston 50 in horizontal direction. The piston of the hydraulic piston 50 is provided with a chuck 58, which in the position of the hydraulic piston 50 of Fig. 3 is pressed

10 against the arrester 56. Thereby the hydraulic piston 50 and the guide plate 22 reach a first end position that provides a desired width of the gap 20 between the guide plate 22 and the drum 8. Preferably the piston of the' hydraulic piston 50 is provided with a threaded adjusting device for fine adjustment of the width of the gap 20 when the chuck 58 of the hydraulic piston 50 is pressed against the arrester 56.

In the operation-ready state of Fig. 3 the hydraulic piston 50 has thus transfered the lower part 48 of the guide plate 22 in the direction towards the drum 8 for providing the width of the gap 20 desired for operation. The hydraulic piston 50 is preferably provided with a mechanical fastener known per se, by means of which the hydraulic piston 50 is fixed in the position illustrated in Fig. 3 also after pressure of the hydraulic system has been released. As an alternative for such mechanical fastening in the hydraulic piston 50 itself, the trough 24 can, according to an alternative embodiment, be provided with a pin, illustrated as an upwards directed pin 60 in Fig. 3, which locks the guide plate 22 in the operating position. This pin 60 is pushed into the lower part 48 of the guide plate 22 when the trough 24 is pushed vertically upwards to its operating position and locks the guide plate 22 in its operating position. When the trough 24 is lowered for cleaning, which is described in more detail with reference to Fig. 5, the pin 60 follows therewith downwards and is drawn out from the guide plate 22, which is thus released. A further alternative embodiment is to keep the hydraulic piston 50 constantly

11 pressurized under operation of the press, so that the guide plate 22 is thereby kept in its operating position.

Fig. 4 illustrates the guide plate 22 shown in Fig. 3 during the operation of the press 1. In the position shown in Fig. 4 the hydraulic piston 50 thus keeps the guide plate 22 in the position that provides the desired width of the gap 20.
As becomes obvious from Fig. 4, liquid suspension is led in via the inlet 4 and further. to the distribution screw 2. The distribution screw 2 distributes the liquid suspension along the active length LT. of the drum 8, shown in Fig. 1, and then leads the liquid suspension further to the feed channel 18. Via the feed channel 18 the liquid suspension reaches the gap 20 and is pressed between the drum 8 and the pressing surface 36 of the guide plate 22 under rotation of the drum 8, which rotation is illustrated with an arrow R, during production of still dryer pulp. After being pressed between the pressing 1.5. surface 36 of the guide plate 22 and the drum 8, the pulp is further pressed to a higher, dry solids content between the drum 8 and the trough 24 as is partly .illustrated in Fig. 4, but becomes best obvious from Fig. 2.

Fig. 5 is a cross-sectional view and illustrates the guide plate 22 of Fig. 3 according to an embodiment of the present invention in a maintenance position. The maintenance position is used e.g. when pulp has stuck in the gap 20. In that kind of situations, the trough 24 illustrated in Fig. 1 and 2 will be lowered vertically downwards, in accordance with arrow N shown in Fig. 2, which allows access to the lower part of the drum 8 for cleaning. Such a vertical lowering of a trough is known per se and described e.g. in the right-hand column of Fig. 1 of EP 1035250. Again, with reference to Fig. 5 of the present invention it becomes obvious that the trough 24 is not anymore in its operating position. The guide plate 22 is released from the trough 24, as the guide plate 22 is mounted on the press 1 itself and not on the transferrable trough 24. Thereby, the guide plate 22 does not follow the vertical lowering downwards of the trough 24. In addition to lowering of the trough 24 downwards, also the hydraulic piston 50 becomes activated, according to the method of an embodiment of the present invention, as the control system 54

12 of Fig. 1 controls the source 52 of pressurized hydraulic liquid in order to draw back the guide plate 22 from the drum 8, i.e. the hydraulic piston 50 draws the lower end 48 of the guide plate 22 in a direction B away from the drum 8, whereby the guide plate 22 is rotated around the horizontal shaft 30 in a direction towards the distribution screw 2. In the position shown in Fig. 5 the hydraulic piston 50 draws the guide plate.22 towards the mechanical arrester 56, whereby the hydraulic piston 50 and the guide plate 22 reach another end position. As the hydraulic piston 50 draws the lower end 48, the guide plate 22 will at its upper end 44 be rotated around the symmetrical axis of shaft 30.
By this movement, the gap 20 is widened and a longest distance, illustrated with S in Fig. 5, is formed between the drum 8 and the pressing surface 36 of the guide plate 22 at the lower end 48 of the guide plate 22. As a result, pulp that has stuck between the pressing surface 36 and the drum 8 either is released by itself and falls downwards, out of the gap 20, and/or an operator can simply insert a cleaning instrument, or just his hand, in the gap 20, which due to the hydraulic piston 50 drawing back the lower end 48 of the guide plate 22 has been widened to an accessable width, and release the stuck pulp. As becomes obvious from Fig. 5 the gap 20 will be widened the whole way up to the upper end 44 of the guide plate 22, i.e. up to the inlet into the feed channel 18, with the result that an operator can simply get access to pulp that has stuck in the gap 20 up to the position where the feed channel 18 discharges into the gap 20, which is an essential advantage compared to prior art, e.g. EP 1035250, in which it is very difficult to get access to and release pulp that has stuck in the vicinity of a corresponning inlet. Further, the guide plate 22 has according to the present invention, a remarkably simpler construction than the baffle shown in EP 1035250. A further advantage is that the guide plate 22 in its backdrawn position illustrated in Fig. 5 does not require any space at the side of the press, unlike the solution presented in EP
1035250. Therefore, a press 1 with a guide plate 22 according to the present invention can be placed in locations with limited space.

When the gap 20 has been cleaned off pulp the guide plate 22 can be returned by means of the hydraulic pistons 50 to the operation-ready state

13 shown in Fig. 3, and the trough 24 can be returned to the position-shown in Fig. 1, so that fiber suspension can again be fed, via inlet 4, the distribution screw 2 and the feed channel 18 to the gap 20.

It will be appreciated that many variants of the embodiments described above are conceivable within the scope defined by the appended claims.

In the above it has been described how the press 1 is utilized for dewatering a liquid suspension comprising cellulose fibers. It is understood that the press 1 can also be utilized for dewatering of suspensions of other types of solid biological material. Examples of such materials include various types of biomasses to be dewatered, and possibly washed, before using for production of fuel, e.g. via an ethanol production process, a biogas production process, or a fuel pellet production process. It is also possible to utilize the press for dewatering a biomass prior to combustion thereof. Examples of biomasses that can be dewatered in the above described press include straw, bagass, other annual plants, grass, vegetable tops, leaves, coniferous litter, algae, moss etc. The liquid in the suspension can be water, but also other liquids, e.g. various organic or inorganic solvents can be present in the suspension to be dewatered.

It has been described in the above that the press 1 is provided with one or more washing devices 28. It is understood that the press can also be designed devoid of these devices, if the material to be dewatered does not require washing.

It has been described in the above how the hydraulic pistons 50 connected to a source 52 of pressurized hydraulic liquid can be utilized for controlling the positions of the guide plate 22. It is understood that other transfer members operating in horizontal direction can be utilized. For instance, the hydraulic pistons can be replaced with usual hydraulic lifters that are manually pumped to a desired position for the guide plate 22. Another possibility is to utilize as transfer members threaded rods with adjusting bolts, which run under the

14 distribution screw 22 and the transfer position of which can be adjusted by means of a stationary key.

In the above it has been described a press 1 having two oppositely rotating dewatering drums 8, 12. The present invention can also be applyid in presses having a single dewatering drum.

Claims

1. A press comprising a distribution device (2) arranged to receive a liquid suspension of solid biological material and to distribute said suspension horizontally along a dewatering drum (8), a guide plate (22) and a trough (24) arranged under the dewatering drum (8), which plate and trough are arranged at a distance from the dewatering drum (8) for forming a gap (20) between the dewatering drum (8) on one side and the guide plate (22) and the trough (24) on the other side, in which gap (20) liquid can be pressed from the suspension under operation of the press for forming a dewatered pulp of the solid biological material, and a feed channel (18) arranged to lead the liquid suspension from the distribution device (2) to said gap (20), characterized in that the guide plate (22) is rotatable around a horizontal shaft (30), said horizontal shaft (30) being arranged at a first end (44) of the guide plate (22), whereby a transfer member (50) is connected to the guide plate (22) at a second end (48) of the guide plate (22) opposite the first end (44) of the plate for adjusting a distance (S) of the guide plate (22) from the dewatering drum (8).

2. A press according to claim 1, wherein the first end (44) of the guide plate (22) is positioned above the second end (48) of the guide plate, seen in the vertical direction.

3. A press according to any one of the preceding claims, wherein the guide plate (22) is arranged below said feed channel (18).

4. A press according to any one of the preceding claims, wherein the guide plate (22) has a pressing surface (36) arranged to, together with the dewatering drum (8), form said gap (20), whereby the feed channel (18) has a nozzle end (42) arranged to communicate with the upper end (38) of the pressing surface (36) during operation of the press (1).

5. A press according to claim 4, wherein a sealing strip (40) is arranged between the upper end (38) of the pressing surface (36) and a lower feed plate (34) comprised in the feed channel (18).

6. A press according to any one of the preceding claims, wherein the guide plate (22) is located at least partly on the same horizontal level as the distribution device (2).

7. A press according to any one of the preceding claims, wherein the guide plate (22) is located at least partly between the distribution device (2) and the dewatering drum (8).

8. A press according to claim 7, wherein the guide plate's (22) center part (C) is located between the distribution device (2) and the dewatering drum (8).

9. A press according to any one of the preceding claims, wherein said transfer member is a hydraulically steered transfer member (50).

10. A press according to any one of the preceding claims, wherein said transfer member (50) is arranged to operate in an essentially horizontal direction (B).

11. A method of cleaning a press for dewatering a liquid suspension of solid biological material, said press comprising a distribution device (2) arranged to receive a liquid suspension of solid biological material and to distribute said suspension horizontally along a dewatering drum (8), a guide plate (22) and a trough (24) arranged under the dewatering drum (8), which plate and trough are arranged at a distance from the dewatering drum (8) for forming a gap (20) between the dewatering drum (8) on one side and the guide plate (22) and the trough (24) on the other side, into which gap (20) liquid can be pressed from the suspension under operation of the press for forming a dewatered pulp of the solid biological material, and a feed channel (18) arranged to lead the liquid suspension from the distribution device (2) to said gap (20), characterized in that the guide plate (22) is rotatable around a horizontal shaft (30), said horizontal shaft (30) being arranged at a first end (44) of the guide plate (22), whereby a transfer member (50) is connected to the guide plate (22) at a second end (48) of the guide plate (22) opposite the first end (44) of the plate for adjusting a distance (S) of the guide plate (22) from the dewatering drum (8), whereby the second end (48) of the guide plate (22) is during the cleaning of the press (1) transfered by means of said transfer member (50) in a direction (B) away from the dewatering drum (8), so that the space (20) between the guide plate (22) and the dewatering drum (8) becomes accessible for cleaning.

12. A method according to claim 11, whereby during the cleaning of the press (1) said trough (24) is transfered vertically downwards for access to the lower part of the dewatering drum (8).