JP2010051968A - Screw press and method of adjusting compression ratio of screw press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw press which has a compression ratio easily adjustable in accordance with the properties of an object to be squeezed, and is prevented from deteriorating in dehydration performance. <P>SOLUTION: The inside of casing 32 in which a plurality of exhaust holes discharging dehydration filtrate is formed, is provided with freely rotatable two screw shafts 33, 34, the screw shafts 33, 34 are provided with spiral screw blades 39, 40, and the screw blades 39, 40 comprise: blade bodies 46 provided at the outer circumference of the screw shafts 33, 34; and thickness adjusting plates 47 freely attachably/detachably fitted to the blade bodies 46. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw press used for solid-liquid separation such as sewage sludge and industrial wastewater sludge, and a method for adjusting the compression ratio of the screw press.

  Conventionally, as this type of screw press, for example, there is a biaxial screw press 11 as shown in FIG. The screw press 11 includes a casing 13 formed of a screen 12, a pair of left and right screw shafts 14a and 14b that are inserted in the casing 13 and arranged in parallel, and a spiral shape provided on the outer periphery of the screw shafts 14a and 14b. Screw blades 15a and 15b.

  At one end of the casing 13, a supply unit 16 for supplying a material to be squeezed (sewage sludge or the like) into the casing 13 is provided, and the material to be squeezed is discharged outside the casing 13 at the other end of the casing 13. A discharge unit 17 is provided. A filtration chamber 19 is formed between the screw shafts 14 a and 14 b and the casing 13. The screw shafts 14a and 14b are formed in a taper shape whose diameter increases toward the discharge portion 17 side. The screw shafts 14a and 14b are connected to a rotation driving device 18 that rotates the screw shafts 14a and 14b.

  According to this, when the rotary drive device 18 is driven, both screw shafts 14a and 14b rotate. And the to-be-compressed material supplied in the casing 13 from the supply part 16 is filtered with the screen 12, being conveyed to the discharge part 17 side by rotation of screw blade 15a, 15b.

  At this time, since the screw shafts 14 a and 14 b are tapered, the volume of the filtration chamber 19 decreases toward the discharge portion 17, so that the object to be squeezed is compressed by the volume reduction of the filtration chamber 19, It is squeezed and dehydrated with the shearing force generated by the engagement of the screw blades 15a and 15b, and then discharged from the discharge portion 17 to the outside.

The screw press as described above is described in, for example, Patent Document 1 below.
Patent Document 2 below describes that a flexible member having a thickness corresponding to the properties of the object to be squeezed is attached to the outer periphery of the screw shaft to adjust the size of the filtration chamber in the radial direction. According to this, a compression ratio can be adjusted according to the property of to-be-compressed material.

Patent Document 3 below describes a biaxial screw press that changes the distance between both screw blades by reciprocating one of the screw blades in the axial direction of the screw shaft. Yes.
JP 63-174800 A Patent No. 3838142 JP2007-245224

  However, in the above conventional format shown in FIG. 5, it is difficult to change the compression ratio of the screw press, and it is difficult to adjust the compression ratio according to the properties of the object to be compressed (sewage sludge, etc.). There are challenges.

  Further, as described in Patent Document 2, when a flexible member is attached to the outer periphery of a screw shaft, in a biaxial screw press, one screw blade on the left and right is used as a flexible member on the other screw shaft. In order to prevent contact with the other screw blade or the flexible member of one screw shaft, the distance between the screw shafts is set wide in advance by considering the thickness of the flexible member. It is necessary to keep it. However, when the interval between the screw shafts is set wide as described above, there is a problem that the dewatering efficiency is lowered and the dewatering performance is lowered.

  In the biaxial screw press described in Patent Document 3, when one screw blade is moved to the discharge portion side along the axial direction of the screw shaft, one screw blade and the other screw blade are The interval on the discharge unit side is reduced, but the interval on the supply unit side is increased accordingly. On the other hand, when one screw blade is moved to the supply unit side along the axial direction of the screw shaft, the distance on the supply unit side between one screw blade and the other screw blade is reduced. The interval on the discharge side is enlarged. Thus, when one screw blade is reciprocated along the axial direction of the screw shaft, the volume reduction ratio of the filtration chamber changes repeatedly, but the average compression ratio does not change. Therefore, when the properties of the object to be squeezed fluctuate greatly, it is not possible to cope with it sufficiently.

  It is an object of the present invention to provide a screw press capable of easily adjusting the compression ratio according to the properties of the object to be compressed and preventing a decrease in dewatering performance, and a method for adjusting the compression ratio of the screw press. And

In order to achieve the above object, the screw press according to the first invention is provided with a rotatable screw shaft in a casing in which a plurality of discharge holes for discharging the dehydrated filtrate are formed.
On the outer periphery of the screw shaft, a spiral screw blade is provided for sending the object to be squeezed supplied from the supply unit into the casing to the discharge unit,
The screw blade thickness is adjustable.

According to this, the to-be-squeezed material supplied in the casing from the supply part is squeezed and dehydrated and filtered in the casing while being conveyed to the discharge part side by the rotation of the screw blades.
By increasing the thickness of the screw blades, the spacing between the screw blades in the axial direction of the screw shaft is reduced, thereby increasing the compression ratio. In addition, by reducing the thickness of the screw blades, the distance between the screw blades in the axial direction of the screw shaft is expanded, thereby reducing the compression ratio.

Thus, by adjusting the thickness of the screw blade, the compression ratio can be easily adjusted according to the properties of the object to be squeezed.
In the screw press according to the second invention, a plurality of screw shafts are arranged in parallel,
Screw blades are provided on each screw shaft.

  According to this, in order to adjust the compression ratio by adjusting the thickness of the screw blades instead of adjusting the compression ratio by attaching a flexible member to the outer periphery of the screw shaft, the interval between the screw shafts Need not be set widely. Thereby, it can prevent that spin-drying | dehydration efficiency falls and the fall of spin-drying | dehydration performance can be prevented.

  In the screw press according to the third invention, the screw blade is composed of a blade body provided on the outer periphery of the screw shaft, and a thickness adjusting plate that is detachably attached to at least one surface of the front and back surfaces of the blade body. It is.

  According to this, when a thick thickness adjusting plate is attached to the blade body, the thickness of the screw blade is increased, thereby reducing the interval between the screw blades in the axial direction of the screw shaft and increasing the compression ratio.

  Moreover, when a thin thickness adjusting plate is attached to the blade body, the thickness of the screw blade is reduced, thereby increasing the interval between the screw blades in the axial direction of the screw shaft and reducing the compression ratio.

In the screw press according to the fourth aspect of the present invention, the thickness of the thickness adjusting plate changes in the circumferential direction.
According to this, when the screw blade is rotating, the position of the thick part and the thin part of the thickness adjusting plate change in the circumferential direction (rotation direction), so that the compaction force repeatedly changes (increases / decreases). To do. As a result, free water in the object to be compressed is more easily separated, and the dewatering performance is improved.

In the fifth invention, a rotatable screw shaft is provided in a casing in which a plurality of discharge holes for discharging dehydrated filtrate are formed,
A method for adjusting a compression ratio of a screw press provided with a helical screw blade that feeds the compressed material supplied from the supply unit into the casing on the outer periphery of the screw shaft,
A thickness adjusting plate is attached to and detached from at least one of the front and back surfaces of the blade body provided on the outer periphery of the screw shaft.

  As described above, according to the present invention, by adjusting the thickness of the screw blade, the compression ratio can be easily adjusted according to the properties of the object to be squeezed. Further, since the compression ratio is not adjusted by attaching a flexible member to the outer periphery of the screw shaft, it is not necessary to set a wide interval between the plurality of screw shafts. Thereby, it can prevent that spin-drying | dehydration efficiency falls and the fall of spin-drying | dehydration performance can be prevented.

  Further, by attaching a thickness adjusting plate having a thickness according to the properties of the object to be compressed to the blade body, the interval between the screw blades in the axial direction of the screw shaft is adjusted, and the compression ratio is easily adjusted.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, reference numeral 31 denotes a biaxial screw press used for solid-liquid separation of an object to be squeezed such as sewage sludge and industrial wastewater sludge. The screw press 31 includes a cylindrical casing 32, two rotatable screw shafts 33 and 34 disposed in parallel in the casing 32, and a drive device 35 that rotates the screw shafts 33 and 34 in opposite directions. And have.

  At one end of the casing 32, a supply unit 36 that supplies the object to be compressed into the casing 32 is provided. Further, the other end portion of the casing 32 is provided with a discharge portion 37 for discharging the dewatered pressed product (cake) to the outside of the casing 32. A back pressure plate 38 is disposed in the discharge portion 37 so as to face the other end opening of the casing 32. Both screw shafts 33 and 34 are each formed in a straight shape having a uniform diameter. A filtration chamber 50 is formed between the screw shafts 33 and 34 and the casing 32.

  Helical screw blades 39 and 40 are provided on the outer peripheries of the screw shafts 33 and 34 to feed the object to be squeezed supplied from the supply unit 36 into the casing 32 to the discharge unit 37. Both screw blades 39 and 40 are formed in opposite spirals, and the other screw blade 40 enters the valley formed between the spirals of one screw blade 39 and the other screw blade. One screw blade 39 enters the valley formed between the 40 spirals, and both screw blades 39 and 40 are engaged. Note that the pitch P of one screw blade 39 is narrower toward the discharge portion 37, and similarly, the pitch P of the other screw blade 40 is narrower toward the discharge portion 37.

As shown in FIG. 3, the casing 32 is made of a screen and has a number of discharge holes 41 that open to the inner and outer peripheral surfaces and discharge the dehydrated filtrate.
The drive device 35 includes gears 42 and 43 that are provided at the other end portions of the screw shafts 33 and 34 and mesh with each other, and an electric motor 44 that is interlocked and connected to the other end portion of one screw shaft 34. Yes.

  The back pressure plate 38 is movable in the axial direction A of the screw shafts 33, 34 by the cylinder device 45, and by adjusting the pressure that acts against the other end opening of the casing 32, the squeezing force (dehydration force) is increased. I have control.

  As shown in FIGS. 1 to 3, one screw blade 39 includes a spiral blade body 46 provided on the outer periphery of one screw shaft 33, and one surface of the blade body 46 (that is, the discharge portion 37 side). And a plurality of thickness adjusting plates 47 which are detachably attached to the surface facing the surface. As shown in FIG. 2, each thickness adjusting plate 47 is formed in a fan shape of about 90 ° when viewed from the axial direction of the screw shaft 33. Each thickness adjusting plate 47 is detachably attached to the blade body 46 by a plurality of bolts 48 (attachment means) and nuts 49 (attachment means).

  A plurality of types of thickness adjusting plates 47 having different thicknesses t are prepared. When a thick thickness adjusting plate 47 having a thickness t is attached, the thickness T of one screw blade 39 (that is, the blade The thickness t of the main body 46 + the thickness adjusting plate 47 is increased, and when the thin thickness adjusting plate 47 is attached, the thickness T of one screw blade 39 is decreased. Thereby, the thickness T of one screw blade 39 can be adjusted.

  Similarly to the one screw blade 39, the other screw blade 40 is composed of a blade body 46 and a plurality of thickness adjusting plates 47, and the thickness T of the other screw blade 40 can be adjusted. .

Hereinafter, the operation of the above configuration will be described.
By driving the electric motor 44, both screw shafts 33, 34 rotate in opposite directions, and both screw blades 39, 40 also rotate in opposite directions. The object to be squeezed supplied from the supply unit 36 into the casing 32 is filtered by the casing 32 while being conveyed toward the discharge unit 37 by the rotation of the screw blades 39 and 40. At this time, the dehydrated filtrate is discharged through the discharge hole 41 of the casing 32. Moreover, since the pitch P of each screw blade 39, 40 is narrower toward the discharge part 37 side, the volume of the filtration chamber 50 is reduced toward the discharge part 37 side. It is squeezed and dehydrated by the compaction force due to the volume reduction of the screw and the shearing force due to the engagement of the screw blades 39 and 40, and then discharged from the discharge part 37 to the outside.

  When the thick thickness adjusting plate 47 of the thickness t is attached to the blade body 46, the thickness T of each screw blade 39, 40 becomes thick. As a result, as shown in FIG. 3, the interval B between the screw blades 39, 40 in the axial direction of the screw shafts 33, 34 is reduced, the compression ratio is increased, and the squeezed in the adjacent filtration chamber 50 is compressed. Increases the shear force on the object.

  Further, when the thickness adjusting plate 47 having a small thickness t is attached to the blade body 46, the thickness T of each screw blade 39, 40 is reduced. Thereby, the space | interval B of each screw blade | wing 39,40 in the axial center direction of each screw shaft 33,34 is expanded, a compression ratio reduces, and the shear force with respect to the to-be-squeezed material in the adjacent filtration chamber 50 reduces. .

  Thus, by adjusting the thickness T of each screw blade 39, 40, the compression ratio and the shearing force can be easily adjusted according to the properties of the object to be squeezed. It should be noted that the thickness adjusting plate 47 can be easily replaced with one having various thicknesses t by attaching and detaching the bolt 48 and the nut 49.

  In addition, the screw press 31 in this embodiment is not a conventional screw press that adjusts the compression ratio and shear force by attaching a flexible member to the outer periphery of the screw shaft. Since the compression ratio and the shearing force are adjusted by adjusting the length T, it is not necessary to set a wide interval between the screw shafts 33 and 34. Thereby, it can prevent that spin-drying | dehydration efficiency falls and the fall of spin-drying | dehydration performance can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIG.
A concave portion 60 and a convex portion 61 are formed on the surface of each thickness adjusting plate 47, whereby the thickness t of the thickness adjusting plate 47 changes in the circumferential direction (the rotational direction of the screw blades 39 and 40). To do.

Hereinafter, the operation of the above configuration will be described.
When both screw blades 39 and 40 are rotating, the position of the convex portion 61 (that is, the thick portion) and the position of the concave portion 60 (that is, the thin portion) of the thickness adjusting plate 47 are shifted in the circumferential direction. And the shearing force with respect to the to-be-squeezed object in the adjacent filtration chamber 50 changes (increases / decreases) repeatedly. As a result, free water in the object to be compressed is more easily separated, and the dewatering performance is improved.

In the second embodiment, the thickness t of the thickness adjusting plate 47 is changed in the circumferential direction. However, the thickness t of the thickness adjusting plate 47 may be changed in the radial direction.
In each of the above-described embodiments, as shown in FIG. 2, each thickness adjusting plate 47 is formed in a fan shape of about 90 ° when viewed from the axial direction of the screw shafts 33, 34. Other angles may be used. In addition, although a plurality of thickness adjusting plates 47 divided in a fan shape are attached to the blade body 46, a single continuous thickness adjusting plate 47 having the same spiral shape as the blade body 46 may be attached.

  In each of the above embodiments, the thickness adjusting plate 47 is attached to one of the front and back surfaces of the blade body 46 (that is, the surface facing the discharge portion 37 side). It may be attached to the surface facing the 36 side. Further, the thickness adjusting plate 47 may be attached to both the front and back surfaces of the blade body 46.

  In each of the above embodiments, the thickness adjusting plate 47 is attached to the blade body 46 using the bolt 48 and the nut 49 which are examples of the attaching means, but other attaching means may be adopted as appropriate. Further, the blade body 46 and the thickness adjusting plate 47 may be counterbored or threaded so that the head of the bolt 48 and the nut 49 do not protrude.

  In each of the above embodiments, the thickness adjusting plate 47 is directly attached to the blade body 46. However, a spacer is inserted between the blade body 46 and the thickness adjusting plate 47 so that the thickness T of the screw blades 39 and 40 is increased. May be adjusted.

  In each of the above embodiments, the screw shafts 33 and 34 are formed in a straight shape, and the pitch P of the screw blades 39 and 40 is narrowed toward the discharge portion 37. May be formed in a tapered shape with a diameter increasing toward the discharge portion 37, and the pitches P of the screw blades 39 and 40 may be equal to each other.

  In each of the above-described embodiments, the biaxial screw press 31 has been described, but it may be a single axis or a plurality of three or more axes.

It is the schematic diagram of the screw press in the 1st Embodiment of this invention, and is the figure which made the casing the horizontal cross section and looked at the inside of the casing from the top. It is a XX arrow line view in FIG. It is a YY arrow line view in FIG. It is the schematic diagram which looked at the screw blade | wing of the screw press in the 2nd Embodiment of this invention from the side surface. It is the schematic diagram of the conventional screw press, (a) makes the casing a horizontal cross section, and is the figure which looked at the inside of a casing from the top, (b) is the side sectional view which looked at (a) from the side. .

Explanation of symbols

31 Screw press 32 Casing 33, 34 Screw shaft 36 Supply part 37 Discharge part 39, 40 Screw blade 41 Discharge hole 46 Blade body 47 Thickness adjustment plate T Thickness of screw blade t Thickness of thickness adjustment plate

Claims (5)

In a casing formed with a plurality of discharge holes for discharging dehydrated filtrate, a rotatable screw shaft is provided,
On the outer periphery of the screw shaft, a spiral screw blade is provided for sending the object to be squeezed supplied from the supply unit into the casing to the discharge unit,
A screw press characterized in that the thickness of the screw blade is adjustable. Multiple screw shafts are arranged in parallel,
The screw press according to claim 1, wherein the screw blade is provided on each screw shaft. The screw blade is composed of a blade main body provided on the outer periphery of the screw shaft and a thickness adjusting plate that is detachably attached to at least one surface of the front and back surfaces of the blade main body. Item 3. A screw press according to Item 2. The screw press according to any one of claims 1 to 3, wherein a thickness of the thickness adjusting plate changes in the circumferential direction. In a casing formed with a plurality of discharge holes for discharging dehydrated filtrate, a rotatable screw shaft is provided,
A method for adjusting a compression ratio of a screw press provided with a helical screw blade that feeds the compressed material supplied from the supply unit into the casing on the outer periphery of the screw shaft,
A method for adjusting a compression ratio of a screw press, wherein a thickness adjusting plate is attached to and detached from at least one side of the front and back surfaces of a blade body provided on the outer periphery of the screw shaft.

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