A screw press

Abstract

The present disclosure describes a screw press, comprising a cylindrical screen frame body having a pulp inlet area screen frame, a pulp inlet groove arranged above the pulp inlet area screen frame, and a pressing screw arranged in the screen frame body, wherein the pulp inlet groove is arranged so that the pulp inlet port of the pulp inlet groove is offset in the lateral direction relative to the rotation axis of the pressing screw and is arranged on the opposite side of the rotation direction of the pressing screw.

Description

Technical Field

[0001] The present disclosure relates to a pulp dewatering screw press, and in particular to a screw press. Background Art

[0002] The working principle of the pulp dewatering screw press is: after the pulp falls from the pulp inlet trough into the space formed by the pressing screw and the screen frame, the rotating pressing screw drives the pulp to move toward the equipment outlet. As the diameter of the pressing screw gradually increases from the inlet to the outlet, the pitch of the spiral blade gradually decreases, and the space formed by the pressing screw and the inner wall of the screen frame gradually decreases, the water in the pulp is continuously squeezed out through the sieve holes on the screen frame, thereby increasing the concentration of the pulp.

[0003] The screen frame of the screw press is usually divided into four screen frame sections: pulp inlet area, low pressure area, medium pressure area and high pressure area. The pulp inlet and pulp inlet groove of the current screen frame in the pulp inlet area on the market are arranged directly above the pressing screw, that is, the pulp slurry falls from directly above the pressing screw into the space formed by the pressing screw and the screen frame.

[0004] In the above-mentioned existing solution of feeding pulp from directly above the pressing screw, since the pulp is in a loose state when it just enters the space formed by the pressing screw and the screen frame, the pulp in the pulp feeding section and the low-pressure section is only in the state of filling the space formed by the pressing screw and the screen frame, and no extrusion effect is formed. The water in the pulp cannot be squeezed out from the screen holes of the screen frame under the low extrusion pressure. Therefore, the screen frames in the pulp feeding area and the low-pressure area of ​​most traditional screw presses that feed pulp directly from the top have very little water, or even no water is squeezed out. In this way, the actual effective dehydration length of the screw press is insufficient, the outlet concentration is low, and it cannot meet the high outlet concentration requirements, and it also reduces the working efficiency of the screw press. Usually, in order to increase the outlet concentration, the user needs to extend the dehydration time by reducing the speed of the screw press, but this will cause a decrease in production. Utility Model Content

[0005] In order to at least partially solve the problems of low outlet concentration and insufficient effective dehydration length of a screw press, the utility model provides a screw press, which includes a cylindrical screen frame body having a screen frame in a pulp inlet area, a pulp inlet groove arranged above the screen frame in the pulp inlet area, and a pressing screw arranged in the screen frame body. The pulp inlet groove is arranged so that the pulp inlet port of the pulp inlet groove is arranged on the opposite side of the rotation direction of the pressing screw with an offset in the lateral direction relative to the rotation axis of the pressing screw. Particularly preferably, the pulp inlet groove is arranged so that the inner surface of one side wall of the pulp inlet groove is tangent to the cylindrical inner wall of the screen frame body. Compared with the technical solution in the prior art in which the pulp inlet groove is arranged directly above the pressing screw, the screw press disclosed in the present invention allows the pulp slurry to enter the screen frame in the pulp inlet area along the approximately tangential direction of the circumference of the inner wall of the screen frame, so that the pulp begins to be squeezed as soon as it enters the pulp inlet area of ​​the screw press.

[0006] Alternatively, in some embodiments, the slurry inlet includes a top wall, a pair of oppositely arranged side walls, and oppositely arranged front and rear walls. The slurry inlet may be substantially circular and disposed in the top wall. The rear wall is at least partially inclined, so that the cross-section of the slurry inlet in the longitudinal direction is substantially in the shape of a right-angled trapezoid.

[0007] In particular, in some embodiments, the aspect ratio of the cross section of the feed slot in the longitudinal direction is within the range of 1:1 and 1:1.5, and is particularly preferably 1:1.2. Compared with the feed zone screen frame according to the prior art in which the feed slot is a flat trapezoid or a flat rectangle with a height / width ratio close to or lower than 1:3 in the longitudinal cross section, the screw press according to the present disclosure allows the pulp to fall into the screen frame from the elevated tangential feed slot, and the potential energy of the falling pulp causes the pulp to be squeezed as soon as it enters the feed zone of the screw press, thereby producing a good dewatering effect.

[0008] Alternatively, in some embodiments, a plurality of reinforcing ribs are provided on the outer surfaces of the side walls, front wall and rear wall of the pulp inlet trough, wherein part or all of the reinforcing ribs of at least one of the side walls, front wall and rear wall are arranged into a plurality of columns and rows that intersect each other.

[0009] Alternatively, in some embodiments, a flange structure for mounting a pressure sensor is provided in the range of 1 / 3 to 1 / 2 of the height of the front wall or the rear wall of the pulp inlet groove, and the pressure sensor is used to sense the inlet pressure of the screw press.

[0010] Alternatively, in some embodiments, the screen frame in the pulp inlet area includes an upper screen frame and a lower screen frame, and the upper screen frame and the lower screen frame are fixedly connected to each other. The lower screen frame is substantially semicircular, and the upper screen frame is substantially semicircular. The upper screen frame is provided with a substantially rectangular communication opening with an arc of approximately π / 2 and a communication plate extending vertically upward from the periphery of the communication opening, and the upper surface of the communication plate forms a mounting interface connected to the pulp inlet trough.

[0011] Alternatively, in some embodiments, the connecting plate is arranged to be aligned with the side walls, the front wall and the rear wall of the feed slot, respectively, so that the inner and outer surfaces of the feed slot and the connecting plate are substantially flush. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 shows a perspective view of a screw press according to the present disclosure;

[0013] Figure 2 A perspective view of a pulp inlet trough of a screw press according to the present disclosure is shown;

[0014] Figure 3 Another perspective view of the inlet trough of the screw press according to the present disclosure is shown;

[0015] Figure 4 A perspective view of a screen frame in a pulp inlet area of ​​a screw press according to the present disclosure is shown;

[0016] Figure 5 A cross-sectional view of a screen frame in the inlet area of ​​a screw press according to the present disclosure is shown. DETAILED DESCRIPTION

[0017] The screw press disclosed in the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the utility model will become clearer according to the following detailed description and claims. It should be noted that the accompanying drawings are in a very simplified form and use non-precise ratios, which are only used for the purpose of conveniently and clearly assisting in explaining the embodiments of the utility model.

[0018] Reference Figure 1 The screw press 10 of the present disclosure is described. The screw press 10 includes a screen frame body 100, a pulp inlet trough 200 arranged above the screen frame body 100, and a pressing screw (not shown) arranged in the screen frame body 100. The pressing screw is rotatably arranged around its rotation axis (extending in the x-axis direction) in the screen frame body 100. The pressing screw may include a helix arranged on the shaft.

[0019] The screen frame body 100 is cylindrical, and may be composed of four sections, namely, a slurry inlet area screen frame 110, a low-pressure area screen frame, a medium-pressure area screen frame and a high-pressure area screen frame.

[0020] The stock inlet trough 200 is arranged above the screen frame 110 in the stock inlet area. The stock inlet trough 200 provides an entrance for pulp to enter the screen frame body 100, and includes a top wall 210, a pair of side walls 220 arranged oppositely, and a front wall 240 and a rear wall 230 arranged oppositely. The stock inlet 250 may be in a substantially circular shape and arranged in the top wall 210, such as Figure 2-3 shown.

[0021] The rear wall 230 is at least partially inclined, for example, the upper section of the rear wall 230 can be inclined, so that the cross section of the slurry inlet 200 in the longitudinal direction is substantially in the shape of a right-angled trapezoid. That is, the lower width of the slurry inlet 200 is greater than the upper width.

[0022] Particularly advantageously, the pulp inlet 200 can be arranged so that the pulp inlet 250 of the pulp inlet 200 is arranged on the opposite side of the rotation direction of the pressing screw in a lateral direction (y-axis direction) relative to the rotation axis of the pressing screw. For example, when the pressing screw rotates clockwise from the pulp inlet side to the pulp outlet side, the pulp inlet 250 is arranged on the left side of the pressing screw; when the pressing screw rotates counterclockwise from the pulp inlet side to the pulp outlet side, the pulp inlet 250 is arranged on the right side of the pressing screw. In this way, the pulp falling downward in the vertical direction impacts on the spiral line of the pressing screw moving upward in the vertical direction to increase the relative impact speed. In the embodiment shown in the drawings, the pulp inlet 250 is centrally located relative to the top wall 210 of the pulp inlet 200 and centrally located relative to the pulp inlet 200 in the lateral direction. In some cases, the periphery of the pulp inlet 250 may be inscribed in the periphery of the top wall 210. Thus, the lateral offset arrangement of the pulp inlet 250 relative to the pressing screw causes the slurry inlet slot 200 itself to be lateral offset relative to the pressing screw, such as Figure 1 shown.

[0023] Particularly preferably, the feed groove 200 can be arranged so that the inner surface of one side wall 220 of the feed groove 200 is tangent to the cylindrical inner wall of the screen frame body 100. That is, in the vertical projection of the screw press according to the present disclosure, the side wall of the feed groove coincides with the side edge of the screen frame body. At this time, the feed groove 200 is offset to the maximum allowable extent, and the feed groove 200 does not protrude beyond the lateral range of the screen frame body 100.

[0024] In particular, in some embodiments, the height-to-width ratio of the cross section of the feed slot 200 in the longitudinal direction is within the range of 1:1 and 1:1.5, and is particularly preferably 1:1.2. Compared with the feed zone screen frame according to the prior art in which the feed slot is a flat trapezoid or a flat rectangle with a height / width ratio close to or lower than 1:3 in the longitudinal cross section, the screw press 10 according to the present disclosure allows the pulp to fall from the elevated tangential feed slot into the screen frame, increasing the potential energy of the pulp falling.

[0025] Alternatively, in some embodiments, a plurality of reinforcing ribs 270 or reinforcing plate ribs may be provided on the outer surfaces of the side walls 220, the front wall 240, and the rear wall 230 of the slurry inlet trough 200. Some or all of the reinforcing ribs 270 of at least one of the side walls 220, the front wall 240, and the rear wall 230 are arranged in a plurality of columns and rows that intersect each other. Figure 2-3 As shown, the reinforcing ribs 270 in the side wall 220 form a grid configuration.

[0026] Furthermore, in some embodiments, the pulp inlet trough 200 may be provided with a flange structure 260 for installing a pressure sensor within a range of 1 / 3 to 1 / 2 of the height of the front wall or the rear wall, and the pressure sensor is used to sense the inlet pressure of the screw press.

[0027] Reference Figure 4-5 In some embodiments, the pulp inlet area screen frame 110 includes an upper screen frame 110a and a lower screen frame 110b. That is, the pulp inlet area screen frame 110 can be composed of two halves. The upper screen frame 110a and the lower screen frame 110b are fixedly connected to each other, for example, via fasteners such as screws. The upper screen frame 110a and the lower screen frame 110b are basically semicircular. A roughly rectangular connecting opening 130 with an arc of approximately π / 2 (an angle of 90 degrees) and a connecting plate 121 extending vertically upward from the periphery of the connecting opening 130 are provided in the upper screen frame 110a, and the upper surface of the connecting plate 121 forms a mounting interface 122 connected to the pulp inlet trough 200. In addition, the connecting plate can be arranged to be aligned with the side wall 220, the front wall 240 and the rear wall 230 of the stock inlet trough 200, respectively, so that the inner surface and the outer surface of the stock inlet trough 200 and the connecting plate 121 are substantially flush, so that the pulp can fall from the stock inlet 250 into the screen frame body 100 without hindrance. The upper screen frame 110a and the stock inlet trough 200 are fixedly connected at the mounting interface 122 via fasteners such as screws.

[0028] Compared with the technical solution in the prior art that the pulp inlet trough is arranged directly above the pressing screw, the screw press disclosed in the present invention allows the pulp slurry to enter the pulp inlet area screen frame along the roughly tangential direction of the inner wall circumference of the screen frame, and the pulp falling direction is opposite to the rotation direction of the screw shaft. In this way, the potential energy of the pulp falling is combined with the kinetic energy of the screw shaft rotation, so that the pulp begins to be squeezed as soon as it enters the pulp inlet area of ​​the screw press, and a good dehydration effect is produced, which is equivalent to extending the effective dehydration length of the screw press and improving the discharge concentration of the screw press. Since the gravity potential energy of the pulp falling is used to increase the squeezing effect, the whole process does not require the screw press to provide so much squeezing kinetic energy, and the same discharge concentration can be achieved, which is equivalent to saving energy consumption.

[0029] As used herein, the term "machine direction" or "longitudinal direction" refers to the direction in which the screen frame and thus the pressing screw of the screw press extends, that is, along the axis of rotation of the pressing screw of the screw press, as shown in the x direction in Figure 1. Correspondingly, the "transverse direction" is understood here to be a direction orthogonal to the machine direction or longitudinal direction and orthogonal to the vertical direction, as shown in the Figure 1. Figure 1 The terms “upper”, “lower”, “front” and “rear” indicate relative orientations between elements, which are defined when the screw press 10 according to the present disclosure is positioned relative to a coordinate system as shown in the drawings.

[0030] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] As used in this disclosure and the appended claims, the singular forms "a", "an", "said", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0032] Obviously, those skilled in the art can make various modifications and variations to the screw press disclosed in the utility model without departing from the spirit and scope of the utility model. Thus, if these modifications and variations of the utility model fall within the scope of the claims of the utility model and their equivalents, the utility model is also intended to include these modifications and variations.

Claims

1. A screw press, comprising a cylindrical screen frame body having a screen frame in a pulp inlet area, a pulp inlet trough arranged above the screen frame in the pulp inlet area, and a pressing screw arranged in the screen frame body, characterized in that: The stock feed groove is arranged such that a stock inlet of the stock feed groove is arranged on the opposite side of the rotation direction of the pressing screw with a lateral offset relative to the rotation axis of the pressing screw.

2. The screw press according to claim 1, characterized in that The slurry inlet groove is arranged so that an inner surface of one side wall of the slurry inlet groove is tangent to an inner wall of the cylinder of the screen frame body.

3. The screw press according to claim 1, characterized in that The pulp inlet trough includes a top wall, a pair of oppositely arranged side walls, and oppositely arranged front and rear walls, wherein the pulp inlet port is arranged in the top wall, wherein the rear wall is at least partially inclined, so that the cross-section of the pulp inlet trough in the longitudinal direction is approximately in the shape of a right-angled trapezoid.

4. The screw press according to claim 3, characterized in that The pulp inlet groove is provided with a flange structure for installing a pressure sensor within the range of 1 / 3 to 1 / 2 of the height of the front wall or the rear wall, and the pressure sensor is used to sense the inlet pressure of the screw press.

5. The screw press according to claim 3, characterized in that: The aspect ratio of the cross section of the slurry inlet groove in the longitudinal direction is within the range of 1:1 and 1:1.

5.

6. A screw press according to claim 5, characterised in that The aspect ratio of the cross section of the slurry inlet groove in the longitudinal direction is 1:1.

2.

7. The screw press according to claim 5, characterized in that A plurality of reinforcing ribs are provided on the outer surfaces of the side walls, the front wall and the rear wall of the slurry inlet trough, wherein part or all of the reinforcing ribs of at least one of the side walls, the front wall and the rear wall are arranged into a plurality of columns and rows that intersect each other.

8. The screw press according to claim 3, characterized in that The screen frame in the pulp inlet area includes an upper screen frame and a lower screen frame, and the upper screen frame and the lower screen frame are fixedly connected to each other, wherein: The lower screen frame is substantially semicircular; The upper screen frame is basically semicircular, and is provided with a roughly rectangular connecting opening with a curvature of approximately π / 2 and a connecting plate extending vertically upward from the periphery of the connecting opening, and the upper surface of the connecting plate forms a mounting interface connected to the slurry inlet trough.

9. The screw press according to claim 8, characterized in that The connecting plate is arranged to be aligned with the side wall, the front wall and the rear wall of the slurry inlet trough respectively, so that the inner surface and the outer surface of the slurry inlet trough and the connecting plate are flush.

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