DE1577215A1 - Press for treating a fiber suspension - Google Patents

Description

Press for treating a fiber suspension

The invention relates to the treatment of a pulpy suspension of pesticides, i.e. a fiber suspension and the like. and it relates in particular to an economic plant and a corresponding facility by which the percentage of solid particles in a flowing pulpy pulp can be increased.

The invention also relates to the use of Presses for dewatering or the like, through which a better Pretreatment of the fiber suspension is achieved, for example, the fiber suspension in such a state ▼ is replaced by a more effective treatment in a refining device for fiber retirement is possible. K rs / th

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It is therefore a primary object of the invention to provide improved plant and equipment for the pretreatment of a corresponding "pulpy suspension of pesticides, which can be produced economically and by which such systems more efficient and satisfactory in their operation, more adaptable to one A multitude of areas of application will give less cause for bad work.

Another object of the invention is in a dewatering press or the like. to obtain a drier end product without the need to add any performance.

It is also an object of the invention to reduce the operating pressure in (to reduce the drainage grease or the like, whereby power consumption is reduced, and thus wear and tear of the equipment is avoided without that the device suffers a loss in its efficiency when thickening the pulpy pesticide suspension.

There becomes an improved dewatering press in accordance with the invention created, in which a transverse screw is attached to control the discharge; the transverse The screw also serves as a second stage for squeezing of candy.

It

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It also becomes an improved press in accordance with the invention created, through which a two-stage dewatering process is provided} it thereby becomes an end product achieves »that is drier and that requires less effort requires.

The invention is "by way of example" with reference to the drawing Explained It show:

Pig, 1 a dewatering press in top view in longitudinal section »

Fig. 2 is a partial front view of the device according to Pig, 1 and

Pig. 3 is a performance diagram showing the ratio of Percentage of solid particles in a Kraft pulp * the unit of pressure exerted on the pulp, i.e. on the fiber suspension will.

The device described facilitates the thickening of the pulp suspended in a liquid suspension in the course of the process their movement to finishing devices or the like

lichen

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treatment facilities. When processing the pulp It is often necessary to change the consistency of the liquid pulp mixture. Used for filtering and cleaning the pulp is usually carried as a very small percentage of particulate matter in a liquid carrier. After filtering and cleaning, treatment of the pulp usually includes a refining step. In order to effectively carry out refining, i.e. refining, the consistency of the pulp must be increased. With a special one For example, using commercially available construction of this type, it may be desirable to reduce the percentage of solid particles in a turbidity flowing through from about 5 # to about 3096 to lift · If the pulp is to be placed in a bunker, it is also desirable to check the consistency of the To raise pulp to the maximum at which the material can still be pumped,

Thickening devices in such a plant for treatment a pulp are arranged to receive the filtered and cleaned pulp, up to a selected one Thicken consistency and then use finishing devices or a storage bunker depending on the work requirements respectively. The feed to a finishing device is under pressure, which increases the capacity of the finishing device and the versatility of its operation

is raised.

The device described is capable of extremely treat different materials and it can be used advantageously in the pretreatment of a pulp for other than for papermaking purposes are used to act as a pressure feed device, but it is commonly used as a drainage device or used a washing device operating at low pressure. In the latter case it will be water or another Liquid fed to the pulp and mixed with it before it is fed to the plant described and the water or the other liquid is drained off here again, whereby unwanted solid particles become extremely effective Way to be discharged.

The described embodiment of a device is in the form of a one-piece machine which has a Part of a continuous treatment system for a Represents pulp. The machine picks up diluted pulp and puts the material under pressure in a two-stage process, in which excess liquid is withdrawn and the dewatered i.e. thickened pulp a subsequent one Treatment stage is fed.

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The device described consists of essentially continuous pressing devices staggered relative to one another. It has a housing which is made up of several interconnected parts which rest on a base 10. At one end of the housing is a gear box 11. The gear box 11 contains mutually meshing gears 12 and 13 which sit on shafts H and 15, respectively. The shafts H and 15 are parallel to each other and perpendicularly at a distance parallel to the base 10. One end of the shaft 15 protrudes outward from the gear box 11 and works together with a power-operated drive device in the manner of an electric motor, not shown located part lead the shafts H and 15 through the transmission ^ box 11 through and beyond it into a press cage 16, which partly consists of cage bars 16 ', which run radially at a distance from each other parallel to the shafts H w and 15 and the are arranged together cylindrically. The cage bars 16 'can be spaced apart on the circumference in a known manner, so that drainage slots between them are created. The arrangement of the cage bars 16 'is held together by a series of circumferential clamps 17 which are arranged at a distance from one another and which are each fastened in a known manner with a bolt 18. The cage bars 16 can have several in the longitudinal direction

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be in a line set of rods separated by spacers 19 and connected to each other are; the spacers 19 form a part a housing 21 which partially surrounds the press cage 16.

With the help of B _u mounted worm chsen 22 and 23 are fixedly disposed on the respective shafts 14 and 15 such that their screw turns interfit. The outer edges of the screw flights come close to contacting the cage wall, which is defined by the inner surfaces of the cage bars 16 '. In this way, the advance of the wet fiber suspension through the press cage 16 is a function of the rotation of the conveyor, which is represented by the screws 22 and 23. The twin screw arrangement runs over the entire length of the press cage 16.

The cage inlet 24 is located near the gear box 11, and in the outside of the press cage the protruding ends of the other end of the shafts 14 and 15 are housed.

At their outer ends, the shafts 14 and 15 have lugs which protrude through a cage end plate 25 on these Approaches each sit screw conveyor 22a and 23a, which

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Continuations of the screws 22 and 23 form. The screw conveyors 22a and 23a lie within a tubular housing 26, Sound which one end provided with a splash abuts the side of the cage end plate 25 and is attached to it is.

The tubular housing 26 protrudes from a housing 27 and is "a part of it, this housing 27 being at right angles to the feed cage 16 is arranged · The housing 27 contains a second stage of a serving as a screw conveyor Screw device in the form of a screw 28 which is seated on a shaft 29. The shaft 29 leads in the longitudinal direction in such a way through the housing 27 that the screw 28 sitting on it that of the screws 22 and 23 and their extensions coming discharge crosses. At both ends of the housing 27 has bearings for the shaft 29, ^ and near its discharge side is a discharge opening 31 available, which is shown schematically and dashed in the drawing. In a longitudinal direction Passage 32 is the shaft 29 and the one sitting on it Screw 28 housed, and the peripheral edge of the screw flights almost touches the wall of the passage.

The tubular housing 26 opens at right angles to one

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Side of the passage 32. In the area of this tubular housing 26 and a small distance beyond it in the direction of the Discharge opening 31, the passage 32 has a larger circumference and forms a second dewatering chamber 33. In this enlarged cross-section results in a semi-cylindrical Lower part of the housing 27 has a drainage section 34 · The drainage section 34 consists of rods or Wedge bars 35, which are arranged on the circumference at a distance similar to the cage bars 16 'and which are circumferential with the aid of ron Brackets 36 are held together. The drainage section 34 extends over the length of the drainage chamber 33 and takes up approximately half of the circumference the housing 27 in this area. Inside the housing 27, the screw 28 leads over the drainage section away and at right angles to the adjacent ends of shafts 14 and 15 and the snails seated on them 22 and 23.

One end of the shaft 29 leads through the housing 27, protrudes from it and is on corresponding parts with a power-operated drive engaged, by which the shaft 29 is set in rotation. According to a preferred one The shaft 29 is independent of the embodiment the shaft 14 and 15 driven so that their speed can be changed relatively.

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The device described ensures a two-stage pressurized conveyance of a pulp in the form of a Cloudy, with the released liquids draining off at each stage. The pulp flows into the cage 16 at cage inlet 24 and loses some of its fluids due to gravity flow · Other parts their liquid is spread out with the help of the pressure when the material through the cage with the help of the overlapping Double arrangement of augers 22-23 pushed forward will. The released in this first stage liquids escape between the cage rods 16 ', the one Form the main drainage section between the inlet and the outlet of the press cage 16.

The pipe housing 26 serves as a connection piece, and the moist fiber suspension pushed forward by the snow cobs 22 and 23 is received by the conveyor screws 22a and 23a forming an extension and pushed through the pipe housing 26 into the housing 27. The material is discharged into the second dewatering chamber 33 and taken up directly by the screw 28 which is at right angles relative to the first screw arrangement. The material is then pushed on through the passage 32 and through a constriction 37 and from this second

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Stage of the system discharged via the discharge opening 31. The pressure exerted on the crop by the screw 28 results in a release of further liquid which can escape from the system via the drainage section 34.

The screw 28 creates a backpressure and it also changes the back pressure, the extended to the further transported through the double arrangement of the screws 22 and 23 Good "is exerts i. The screw 28 henceforth provides a fixed discharge of substantially thickened material from the discharge opening 31. In addition, a second dewatering the pulp and thereby an optimum dryness is reached by the screw, woh <z / the pressures released in the cage 16 and in the pipe housing 26 serving as a connecting piece occur.

With respect to these pressures a known relationship between the percentage of * Peststoffteilchen arising at a given pulp, and the printing unit is provided which is applied to the pulp. In Fig. 3 the conditions for applying pressure to a * 'Kraft pulp "are shown schematically, with a gravity dewatering thickening a pulp to about 896 solid particles. Subsequently, an increase per unit of pressure leads to rapid dewatering until a level of about 309 t solid particles. 009839/0277

particle is reached, whereupon, as the curve shows, a change only takes place gradually. An increase in Consistency down to 30 # pesticide particles can be achieved by application a pressure on the order of 35 pounds can be achieved; an increase to 50 # pesticide particle is not feasible unless pressures range from 8,000 to 10,000 psi.

The double arrangement of the screws 22 and 23 and their approaches develop a maximum pressure at that end where there is a change in direction of flow and the Snail 28 exerts a back pressure. To achieve a pressure level along the length of the screws 22 and 23, the is adequate to achieve a pulp consistency of 3096 pesticide particles at its ends, it has been found that without the stated improvements the pressures at the outlet end of the twin screw arrangement are significantly higher must be than the 35 pounds indicated by the diagram in Pig.3 and how they are used for these purposes required are. This higher pressure serves no useful purpose in dewatering. He is due to himself Adjusting wear and tear and the stress on the system disadvantageous and especially because under such conditions the individual parts of the Prtsse are correspondingly heavy and must be built strong in order to be able to cope with pressure resist.

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In the embodiment described, however, a release of such pressures is created which would normally be required at the outlet end of the twin screw arrangement. In a second dewatering process, the dewatering section 34 uses the pressure generated by the screw 28 to squeeze liquids from the pulp entering the housing 27 immediately in front of the discharge opening 31. The pulp is therefore finally dry to the desired consistency in the housing, and the pressures which make this possible are a function of the rotation of the shaft 29 and to a large extent independent of the double arrangement of the screws 22 - 23. Because the pressure developed by screw 28 is used in a second dewatering process, screws 22-23 work against less back pressure and therefore under relatively reduced pressure conditions over their entire length. This results in a substantial reduction in torque, while still the necessary end product by using the second n The drainage level is reached. The consequence of this is a power saving and a much lower wear and tear and corresponding failures in the arrangement,
fewer

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Try the well-known ones with a dewatering press Kind of walked, and with no transverse drainage screw used gave a typical power input for a normal capacity in the range of

0.9 to 1.1 HP · days / to (5911.9 · 10 ³ kp «m to

to

7225 »7 ^β 105 kp * m) _r applied to an unbleached Kraft pulp, with which 305 ^ pesticide particles were obtained * (1 HP * hr β 273.7 · 10 V p · m) - When using a transverse screw for dewatering as described, the power input which must be used to achieve 30/6 solid particles in the end product falls to about

0.5 HP · days / to (3284.4.10 ⁵ kp » m) .

to

In summary, the use of the dewatering section 34 results in the pressure on the discharge ends of the screws 22 - 23 reduced, the pressure in the dewatering section of the double arrangement of the screws within moderate limits and that overall torque exerted on the screws is reduced. Also, in order to achieve 30 # pesticide particles, im

Compared to 1 HP · days / to (6568.8 · 10 ⁵ kp «m ) like them

ta were previously necessary, now a power supply of

about 0.5 HP days / to (3284.4 10 ⁵ kp m) are necessary for a Kraft pulp, which means a power saving of approximately less.

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Due to the described structure, the most varied of advantages are given. Because the pressures in the section with the twin screw arrangement are reduced, a more economical press can be designed and a lighter press can be built. The effort required can be reduced very substantially, achieving the same degree of thickening as was achieved by more expensive known equipment. In addition, a greater g dryness of the final product can be achieved than would be achieved in a press without a transverse dewatering screw. Finally, excessive friction and wear in the section with the twin screw arrangement, such as that caused by the screws which are subjected to high end pressures, is avoided.

With regard to the liquids removed, the following should also be noted: based on experience and as from the Diagram according to Fig. 3 can be seen, drain pressures of " about 25 psi (1.76 kg / cm) most fiber suspensions from a pumpable slurry to about 20 # solid particles. With the embodiment described, the high volume of liquid to be removed can easily be in the section with the double corner arrangement. If, for example, 100 tons of a fiber suspension in the form of a pulp with a content of solid particles

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of 5 # has, in twenty-four hours on a salary of solid particles of 30 # are dewatered, so is it needs to be approximately 250 gallons (946 It) per minute To dispense fluid at an incoming rate of 300 gallons (1136 It) per minute. To of 5 # particulate matter To get to 20? έ solid particles means one Withdrawing 225 gallons (852 It) per minute

W staged continuous operation, as it has been described, one can utilize the section with the twin-screw arrangement more effectively with lower power and higher volumes. For the case of 100 tons per day, about 225 gallons (852 It) per minute would be withdrawn in the lower pressure main drainage section. If the material is then solidified and has about 20 ^ solid particles, then the single screw 28 working with higher pressure acts in connection with the dewatering section 34 as a second dewatering device

only has to withdraw 25 gallons (94.6 It) per minute, to the desired consistency of 30 # particulate matter reach.

The transverse drainage screw can also be combined can be used with a single screw at the low pressure end of the press instead of with a twin screw arrangement 22-23. However, two have snails

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certain advantages over a single screw arrangement, for example by being able to are to pick up a slurry of very low consistency and convey it on.

Claims i

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Claims (10)

Claims 1) Press for treating a fiber suspension, for example for dewatering, with a first cage section, one inlet and one outlet and a screw conveyor arrangement for advancing pulp in the form of a pulp such that the pulp moves from the inlet to the outlet and through it, the screw arrangement being adapted to allow liquid from the pulp to flow through it as it moves the first cage portion is withdrawn and the first cage portion is formed so that it is the withdrawn Liquid drains, characterized in that a housing section in closed connection with the The outlet of the first cage section stands and creates an Austra & jä passage, which is at an angle across the The outlet of the first cage section extends so that the housing section has a discharge opening at its other end from the end portion of the passage has that an independent auger assembly rotatably disposed in the passage so as to take the picks up thickened pulp from the first cage section and exerts a counterpressure on the through the first cage section moving · Turbidity causes the independent sonic arrangement to concentrate the fibrous material in the thickened Clouds 009839/0277 Cloudy continues to be compressed and the resulting product is positive towards the discharge opening and through it conveyed and that devices in connection with the housing section for an operation of the independent Ensure located therein screw arrangement so that for the first screw arrangement in the first Cage section conditions are created to operate under minimal pressure without loss of efficiency is working. 2) Press according to claim 1, characterized in that the devices are formed by a drainage section of the housing section, which enables the outflow of clay liquid that has been released from the thickened sludge by the action of the independent screw arrangement. 3) Press according to claim?, Characterized in that the drainage section of the housing section forms part of the passage at that end which is relatively adjacent to the outlet from the first cage section 4) Press according to claim 2, characterized in that the housing section has a constriction in the passage immediately 009839/0277 has immediately in front of the discharge opening where the independent screw arrangement forms a plug from the thickened material originating from the pulp. 5) Press according to claim 1, characterized in that the devices consist of a sub-section of the housing section which is formed with slots and that under the independent scroll assembly in an enlarged area of the passage nearby the outlet from the first cage section is 6) Press according to claim 1, characterized in that a fitting piece is the first cage section and the housing section connects together, and that the screw arrangement in the first cage section in the fitting has lying extensions which are in the immediate vicinity of the end of the independent screw arrangement, opposite to the discharge opening, end. 7) Press according to claim 1, characterized in that the passage in the housing portion in the vicinity of the Outlet from the first cage section is relatively widened and that in the widened section dee Passage of the housing section with several drain openings is provided. 8th} 009839/0 2 77 8) press according to claim 7, characterized in that in the passage between the enlarged portion and a constriction is provided for the discharge opening 9) press for dewatering or the like. of fiber suspensions, characterized in that there is a first stage and a second stage of a screw conveyor arrangement is that the second stage is arranged at an angle across the discharge end of the first stage and is independent is driven by it that a housing arrangement forms a passage for the suspension in which the screw assemblies sit that the housing has an inlet for the material to be thickened, that of the first stage is to be fed, has at one end that is remote from the second stage that the housing in the Area of the first stage of the screw conveyor arrangement Has drain openings substantially over their entire length that an outlet from the housing of the Passage at the end of the second stage of the screw conveyor assembly remote from the first auger assembly leads, and that the housing also around a A portion of the second stage of the auger assembly has a drainage section which is so arranged is that it creates an enlarged section of the passage. 10) 009839/0277 10) device for thickening a wet suspension, characterized in that a first section is a The first press for pushing the material forward from the inlet to the outlet has that dewatering devices are provided in the first press section a second press section is arranged at an angle to the first preening section and an extension fc forms for him that a second press in the second Press section in closed connection with the Discharge of the first press is arranged so that their discharge is recorded and its direction of movement is changed that in the course of this process in the first press section a back pressure takes place that the second press section a drainage ^ section which is constructed so that the back pressure is controlled in the first press section, whereby the first press acts on the material pushed forward by it and presses liquids out of the material under optimal pressure conditions that the second Press liquids from the thickened material delivered from the first press section withdrawn, resulting in an end product that has a minimal liquid content, and that the end product is obtained with minimal power consumption « 009839/0277 Blank page