JP5660928B2 - Screw press - Google Patents

Description

  The present invention relates to a screw press that dehydrates an object to be dehydrated such as organic sludge.

  Conventionally, as this type of screw press, for example, there is a biaxial screw press 70 as shown in FIG. In the screw press 70, two upper and lower screw shafts 72 and 73 are inserted into a cylindrical screen 71, and spiral screw blades 74 and 75 are provided on the outer circumferences of the screw shafts 72 and 73.

  The sludge 76 is supplied from the sludge supply port 77 to one end portion in the screen 71. The sludge supply port 77 is formed in one side wall 79 of the main body casing 78 facing one end of the screw blades 74 and 75 in the axial direction of the screw shafts 72 and 73.

The other side wall 80 of the main body casing 78 is provided with a sludge discharge portion 81 for discharging the dehydrated sludge 76 from the screen 71.
Both screw shafts 72 and 73 are straight shafts having a constant shaft diameter D in the screen 71, and are formed in opposite directions A. Rotate to B. Further, both screw blades 74 and 75 have spirals in opposite directions, and are configured such that the pitch becomes narrower toward the sludge discharger 81 side which is the downstream side.

  A dewatering portion 82 is formed between the outer peripheral surfaces of the screw shafts 72 and 73 and the inner peripheral surface of the screen 71 in the axial direction. The screen 71 is provided with a concentration zone 83 for mainly dewatering sludge 76 by gravity filtration and a dewatering zone 84 for mainly dewatering sludge 76 by pressing. The cake thickness is determined based on the area of the screen 71 required in the dewatering zone 84 and the dewatering time, and the shaft diameters D of the screw shafts 72 and 73 are determined based on the cake thickness.

  According to this, the sludge 76 is supplied to the one end part in the screen 71 from the sludge supply port 77 in the state which rotated both screw shafts 72 and 73 to the mutually opposite directions A and B. Thereby, the sludge 76 is conveyed in the screen 71 toward the sludge discharge part 81 by the screw blades 74 and 75 rotating integrally with the screw shafts 72 and 73, and the pitch of the screw blades 74 and 75 is gradually reduced. It is dehydrated and discharged from the screen 71 to the outside through the sludge discharger 81. Further, the dehydrated filtrate passes through the screen 71 from the inside to the outside and is discharged.

  In addition, about the biaxial screw press 70 as mentioned above, there exist some which are described in the following patent document 1, for example.

JP 2009-136919 A

  However, in the above conventional type, since the size E in the axial diameter direction of the dewatering unit 82 is small at the end on the sludge supply port 77 side which is one end of the screw shafts 72 and 73, the sludge 76 is removed from the sludge supply port 77. When supplied into the screen 71, there is a problem that the fluidity of the sludge 76 in the dewatering section 82 is lowered, and the sludge 76 does not spread uniformly on a plane perpendicular to the axis of the screw shafts 72 and 73. For this reason, the filtration area at one end portion of the screen 71 responsible for the initial filtration (that is, the end portion on the sludge supply port 77 side) is not effectively used over the entire circumference, and the filtration is locally performed in the circumferential direction of the one end portion of the screen 71. As a result, the load on the screen 71 increases locally, and the SS recovery rate may decrease.

  An object of this invention is to provide the screw press which can supply a to-be-dehydrated material into a filtration cylinder from a supply part, and can spread uniformly.

In order to achieve the above object, the first invention of the present invention includes a filter cylinder capable of discharging a dehydrated filtrate,
A rotatable screw shaft inserted into the filter cylinder;
Screw blades provided on the outer periphery of the screw shaft;
A screw press having a supply unit for supplying the material to be dehydrated into the filter cylinder,
The screw shaft has a large-diameter shaft portion and a small-diameter shaft portion having a smaller diameter than the large-diameter shaft portion,
A step portion is formed at the boundary between the large diameter shaft portion and the small diameter shaft portion,
A dewatering part is formed between the outer peripheral surface of the large-diameter shaft part and the inner peripheral surface of the filter cylinder,
Between the outer peripheral surface of the small-diameter shaft portion and the inner peripheral surface of the filter tube, a reservoir is formed to store the dehydrated material supplied from the supply unit into the filter tube,
The supply part opens to the reservoir,
The material to be dehydrated supplied from the supply unit to the reservoir can pass through the screw blades and move in the axial direction.

  According to this, the screw blade is rotated integrally with the screw shaft, and the material to be dehydrated is supplied from the supply part to the reservoir part in the filtration cylinder. Since the small-diameter shaft portion of the screw shaft is smaller in diameter than the large-diameter shaft portion, the reservoir portion is formed larger than the dewatering portion in the axial diameter direction, and the material to be dewatered easily flows in the rotational direction of the screw shaft in the reservoir portion. The fluidity of the material to be dehydrated in the pool is improved, and the material to be dewatered is uniformly distributed in the pool.

  As a result, the filtration area in the reservoir is effectively used over the entire circumference, and the dehydrated material is uniformly filtered over the entire circumference of the filter cylinder in the reservoir, so that the load in the reservoir is almost uniform without local concentration. It is possible to prevent the SS recovery rate from being lowered.

  Note that the material to be dehydrated supplied from the supply unit to the reservoir is dehydrated while being sent from the reservoir to the dehydrator by the rotating screw blades. At this time, since the material to be dehydrated supplied to the reservoir passes through the screw blades and moves in the axial direction, the fluidity of the material to be dehydrated in the reservoir is further improved.

In the screw press according to the second aspect of the present invention, the screw blade has a dewatering portion screw blade provided on the outer periphery of the large-diameter shaft portion of the screw shaft, and a reservoir portion screw blade provided on the outer periphery of the small-diameter shaft portion,
The reservoir screw blade has an opening that opens in the axial direction.

  According to this, since the to-be-dehydrated substance supplied to the reservoir part from the supply part passes through the opening part of the reservoir part screw blade, and moves to an axial direction, the fluidity | liquidity of the to-be-dehydrated substance in a reservoir part further improves.

In the screw press according to the third aspect of the present invention, a plurality of screw shafts are inserted into the filter cylinder,
Screw blades are provided on each screw shaft,
The filter cylinder has a curved shape along the outer periphery of the screw blade.

  According to this, by rotating each screw shaft, each screw blade rotates together with each screw shaft. The material to be dehydrated supplied from the supply unit to the reservoir is dehydrated while being sent from the reservoir to the dehydrator by each screw blade.

Moreover, since the filtration cylinder has a curved shape along the outer periphery of the screw blade, the dehydrated material can be filtered using the entire circumference of the filtration cylinder in the reservoir.
In the screw press of the fourth invention, adjacent screw shafts rotate in opposite directions,
The supply section is located on the side where both screw blades are separated and sent in the respective rotation directions from between both shaft centers.

  According to this, immediately after being supplied from the supply unit to the reservoir, the dehydrated material is divided and sent out in the respective rotation directions (that is, two different directions) by both screw blades rotating in opposite directions. . Thereby, the fluidity | liquidity of the to-be-dehydrated substance in a reservoir part further improves.

In the screw press according to the fifth invention, a plurality of screw blades are provided on the screw shaft.
In the screw press according to the sixth invention, the large-diameter shaft portion and the small-diameter shaft portion of the screw shaft are respectively straight shafts.

  As described above, according to the present invention, it is possible to supply the material to be dehydrated from the supply unit into the filtration cylinder and distribute it uniformly, so that the filtration area in the reservoir is effectively used over the entire circumference. Since the material to be dehydrated is filtered uniformly over the entire circumference of the filter cylinder in the reservoir, the load in the reservoir is distributed almost evenly without being concentrated locally, and a reduction in the SS recovery rate can be prevented.

It is sectional drawing of the screw press in embodiment of this invention. It is sectional drawing of the accumulation part of a screw press same as the above. FIG. 3 is an XX arrow view in FIG. 2. It is a YY arrow line view in FIG. It is a ZZ arrow line view in FIG. It is sectional drawing of the conventional screw press.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 5, reference numeral 1 denotes a screw press for dehydrating an object 2 to be dehydrated such as organic sludge, which is of a biaxial two-row type. The screw press 1 includes a casing 5, a filter cylinder 6 capable of discharging dehydrated filtrate, two upper and lower (multiple) rotatable screw shafts 7 and 8 inserted into the filter cylinder 6, and each screw shaft 7. , 8 on the outer periphery of the screw blades 33 to 36 spirally provided on each outer periphery, and a supply port 11 (an example of a supply unit) for supplying the dehydrated material 2 to one end of the filter tube 6. The discharge part 12 that discharges the dehydrated material 2 to the outside from the other end in the filter cylinder 6, the back pressure plate 13 that can be moved back and forth toward the opening of the discharge part 12, and both screw shafts 7 and 8. And a rotation driving device 14 for rotating the motors in opposite directions A and B.

  The casing 5 has a pair of standing wall portions 16 and 17 that are arranged to face each other in the axial direction of the screw shafts 7 and 8. The filter cylinder 6 is made of, for example, a screen and has a plurality of dehydrated filtrate discharge holes 9 for discharging the dehydrated filtrate dehydrated and separated from the dehydrated material 2, and is attached between the compatible wall portions 16 and 17. . Moreover, the filtration cylinder 6 is formed in the shape (curved surface shape) curved along the outer periphery of the screw blades 33 to 36, and has an upper filter chamber 18 and a lower filter chamber 19 inside. As shown in FIG. 3, both side surfaces of the filter cylinder 6 are formed in a pair of upper and lower circular arcs, and have a recess 6 a in which the upper and lower central portions are recessed.

  Both screw shafts 7 and 8 are horizontally arranged in parallel, and both end portions of the screw shafts 7 and 8 are supported by the casing 5 through bearings so as to be rotatable. The upper screw shaft 7 is provided in the upper filter chamber 18, and has a large diameter shaft portion 7a and a small diameter shaft portion 7b provided at one end of the large diameter shaft portion 7a. The large diameter shaft portion 7a occupies most of the length in the filter cylinder 6, and the shaft diameter Db of the small diameter shaft portion 7b is set smaller than the shaft diameter Da of the large diameter shaft portion 7a. The large-diameter shaft portion 7a and the small-diameter shaft portion 7b are straight shafts, respectively, and a stepped surface 21 perpendicular to the axis 20 of the screw shaft 7 is formed at the boundary between the large-diameter shaft portion 7a and the small-diameter shaft portion 7b. (An example of a step part) is formed.

  The lower screw shaft 8 is provided in the lower filter chamber 19 and has a large-diameter shaft portion 8a and a small-diameter shaft portion 8b in the same manner as the upper screw shaft 7. A stepped surface 23 (an example of a stepped portion) orthogonal to the axis 22 of the screw shaft 8 is formed at a boundary portion between the large diameter shaft portion 8a and the small diameter shaft portion 8b.

  Between the outer peripheral surface of the upper small-diameter shaft portion 7 b and the inner peripheral surface of the filter tube 6 and between the outer peripheral surface of the lower small-diameter shaft portion 8 b and the inner peripheral surface of the filter tube 6, a filter tube is connected from the supply port 11. A reservoir 25 is formed to store the dehydrated material 2 supplied into the interior 6. Further, there is a reservoir between the outer peripheral surface of the upper large-diameter shaft portion 7a and the inner peripheral surface of the filter tube 6 and between the outer peripheral surface of the lower large-diameter shaft portion 8a and the inner peripheral surface of the filter tube 6. A dewatering section 26 communicating with the downstream side of the 25 is formed. As shown in FIGS. 1 and 2, the size F of the pool portion 25 in the axial diameter direction is formed larger than the size E of the dewatering portion 26.

  The upper screw blades 33 and 34 and the lower screw blades 35 and 36 are formed so as to draw a spiral in directions opposite to each other, and the pitch P becomes narrower toward the discharge portion 12 which is the downstream side. Is set to

  The two screw blades 33 and 34 provided on the upper screw shaft 7 are respectively a dewatering portion screw blades 33a and 34a provided on the outer periphery of the large-diameter shaft portion 7a and a reservoir provided on the outer periphery of the small-diameter shaft portion 7b. Part screw blades 33b, 34b. Similarly, the two screw blades 35 and 36 provided on the lower screw shaft 8 also have dewatering portion screw blades 35a and 36a and pool portion screw blades 35b and 36b, respectively.

The reservoir screw blades 33b to 36b are continuously extended from the dehydrator screw blades 33a to 36a.
Each of the reservoir screw blades 33b to 36b has an opening 27 that opens in the axial direction at the root portion on the inner peripheral side.

  As shown in FIG. 1, the filtration cylinder 6 is provided with a concentration zone 38 for mainly dehydrating the dehydrated material 2 by gravity filtration and a dehydrating zone 39 for mainly depressing and dewatering the dehydrated material 2. ing. The concentration zone 38 is set on the supply port 11 side which is one end side of the filter cylinder 6, and the dehydration zone 39 is set on the discharge section 12 side which is the other end side of the filter cylinder 6. The pore diameter of the dehydrated filtrate discharge hole 9 included in the concentration zone 38 is formed larger than the hole diameter of the dehydrated filtrate discharge hole 9 included in the dehydration zone 39. Is low, but the effective filtration area is large, and in the dehydration zone 39, the compression pressure is high but the effective filtration area is small.

  The thickness of the cake is determined based on the area of the filter cylinder 6 required in the dewatering zone 39 and the dewatering time. Based on the thickness of the cake, the large-diameter shaft portions 7a, The shaft diameter Da of 8a is determined.

  As shown in FIGS. 3 and 4, the supply port 11 is formed in one standing wall 16 and opens to the reservoir 25, and both the upper screw blades 33 and 34 and the lower screw blades 35 and 36 are provided. The upper screw blades 33, 34 and the lower screw blades 35, 36 are axial centers 20, 22 with respect to a straight line L that is opposed to the overlapping portion C in the axial direction and passes between both the shaft centers 20, 22. It is located on the side that is sent out separately in the respective rotation directions A and B.

  As shown in FIGS. 1 and 2, the rotary drive device 14 is engaged with upper and lower driven gears 29 and 30 that are provided at one end of both upper and lower screw shafts 7 and 8 and mesh with each other, and a lower driven gear 30. And a motor 32 that rotationally drives the drive gear 31.

The back pressure plate 13 adjusts the pressure that acts against the opening of the discharge unit 12 by moving back and forth in the axial direction by the cylinder device 37.
Hereinafter, the operation of the above configuration will be described.

  The upper screw blades 33 and 34 and the lower screw blades 35 and 36 are rotated in opposite directions A and B integrally with the screw shafts 7 and 8 by the rotation driving device 14, and the dehydrated material 2 is supplied from the supply port 11. This is supplied to the reservoir 25 in the filter cylinder 6.

  Since the reservoir portion 25 is formed larger than the dewatering portion 26 in the axial direction, the material to be dehydrated 2 can easily flow in the rotational directions A and B of the screw shafts 7 and 8 in the reservoir portion 25. The fluidity of the material to be dehydrated 2 at 25 is improved, and the material to be dehydrated 2 spreads uniformly in the reservoir 25.

  In addition, since the dehydrated material 2 supplied to the reservoir 25 moves in the axial direction through the openings 27 of the reservoir screw blades 33b to 36b, the fluidity of the dehydrated material 2 in the reservoir 25 is further improved. To do.

  Further, as shown in FIG. 3, the material to be dehydrated 2 immediately after being supplied from the supply port 11 to the reservoir 25, the upper screw blades 33 and 34 rotating in opposite directions A and B and the lower screw blades 33 and 34. The screw blades 35 and 36 are separately sent in the respective rotation directions A and B (that is, different two directions). Thereby, the fluidity | liquidity of the to-be-dehydrated material 2 in the reservoir part 25 further improves.

  As described above, the filtration area in the reservoir 25 is effectively used over the entire circumference, and the dehydrated matter 2 is uniformly filtered using the entire circumference of the filter cylinder 6 in the reservoir 25, so that the load in the reservoir 25 Are distributed almost evenly without being concentrated locally, and a reduction in the SS recovery rate can be prevented.

  In addition, the to-be-dehydrated object 2 supplied to the reservoir 25 from the supply port 11 is dehydrated while being sent from the reservoir 25 to the dehydrator 26 by the rotating screw blades 33 to 36, and then from the opening of the discharge unit 12. It is discharged outside.

  In the above embodiment, the two screw shafts 7 and 8 are arranged in parallel in the vertical direction, but may be arranged in parallel in the horizontal direction. Further, both screw shafts 7 and 8 may be slightly inclined rather than parallel.

  In the above-described embodiment, the biaxial screw press 1 having two (plural) screw shafts 7 and 8 has been described. However, a single screw screw press having one screw shaft may be used. . Further, it may be a multi-shaft type screw press having three or more screw shafts.

  In the above-described embodiment, a double-type screw press 1 in which two screw blades 33 and 34 are provided on one screw shaft 7 and two screw blades 35 and 36 are provided on the other screw shaft 8 is shown. However, it may be a single-screw screw press provided with a single screw blade. Further, it may be a multi-strip type screw press provided with three or more screw blades.

  In the said embodiment, although the opening part 27 opened to an axial direction was formed in the root part of the inner peripheral side of each reservoir part screw blade | wing 33b-36b, the to-be-dehydrated material 2 passes through the reservoir part screw blade | wing 33b-36b. As a structure that can be used, for example, a notch may be formed on the outer peripheral side of each reservoir screw blade 33b to 36b, and each reservoir screw blade 33b to 36b is made of a member such as punching metal. Also good. Alternatively, the openings 27 may not be formed in the reservoir screw blades 33b to 36b, and instead, grooves along the axial direction may be formed on the outer peripheral surfaces of the small diameter shaft portions 7b and 8b.

  In the above embodiment, the step surfaces 21 and 23 are orthogonal to the shaft centers 20 and 22 of the screw shafts 7 and 8, but the step surfaces 21 and 23 are not limited to being orthogonal. You may incline and form. Further, the stepped surfaces 21 and 23 may be chamfered or rounded.

  In the above embodiment, each screw shaft 7 and 8 has a large and small two-stage structure having large-diameter shaft portions 7a and 8a and small-diameter shaft portions 7b and 8b, respectively. There may be.

  In the above embodiment, the supply port 11 is formed in one of the standing wall portions 16 and is open to the pool portion 25. However, the position of the supply port 11 is not particularly limited. For example, the supply port 11 is connected to the screw shaft. The dehydrated material 2 may be supplied from the screw shaft, or the supply port 11 may be provided in the filter tube 6 and the dehydrated material 2 may be supplied from the filter tube 6.

DESCRIPTION OF SYMBOLS 1 Screw press 2 Dehydrated object 6 Filter cylinder 7, 8 Screw shaft 7a, 8a Large diameter shaft part 7b, 8b Small diameter shaft part 11 Supply port (supply part)
20, 22 Axes 21, 23 Step surface (step)
25 Reservation part 26 Dehydration part 27 Opening part 33-36 Screw blade 33a-36a Dehydration part screw blade 33b-36b Retention part screw blade A, B Opposite direction, rotation direction

Claims (6)

A filter cylinder capable of discharging the dehydrated filtrate;
A rotatable screw shaft inserted into the filter cylinder;
Screw blades provided on the outer periphery of the screw shaft;
A screw press having a supply unit for supplying the material to be dehydrated into the filter cylinder,
The screw shaft has a large-diameter shaft portion and a small-diameter shaft portion having a smaller diameter than the large-diameter shaft portion,
A step portion is formed at the boundary between the large diameter shaft portion and the small diameter shaft portion,
A dewatering part is formed between the outer peripheral surface of the large-diameter shaft part and the inner peripheral surface of the filter cylinder,
Between the outer peripheral surface of the small-diameter shaft portion and the inner peripheral surface of the filter tube, a reservoir is formed to store the dehydrated material supplied from the supply unit into the filter tube,
The supply part opens to the reservoir,
A screw press characterized in that a material to be dehydrated supplied from a supply part to a reservoir part can move in an axial direction through a screw blade. The screw blade has a dewatering portion screw blade provided on the outer periphery of the large-diameter shaft portion of the screw shaft, and a reservoir portion screw blade provided on the outer periphery of the small-diameter shaft portion,
The screw press according to claim 1, wherein the reservoir screw blade has an opening that opens in an axial direction. A plurality of screw shafts are inserted into the filter cylinder,
Screw blades are provided on each screw shaft,
The screw press according to claim 1 or 2, wherein the filter cylinder has a curved shape along the outer periphery of the screw blade. Adjacent screw shafts rotate in opposite directions,
4. The screw press according to claim 3, wherein the supply section is located on a side where both screw blades are separated from both shaft centers in the respective rotation directions and sent out. The screw press according to any one of claims 1 to 4, wherein a plurality of screw blades are provided on the screw shaft. The screw press according to any one of claims 1 to 5, wherein each of the large-diameter shaft portion and the small-diameter shaft portion of the screw shaft is a straight shaft.

Images