JP2000079351A - Screw mixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw mixer which can crush even a raw material of ultra-high viscosity such as sludge cake. SOLUTION: A mixer 1 which crushes and discharges a raw material is equipped with a hopper 2 having an inlet and a discharge opening and screw shafts 3, 3 which are fixed rotatably in the hopper 2 and in which numbers of blades Tn (n indicates the blade of the nth in the shaft direction) are fitted to its rotary shaft. The blades 5 are fitted to the rotary shaft in a relationship in which, when the difference between the fitting angle of the blade Tn and that of the blade Tn+1 when seen in the rotary shaft direction is θ, (360/θ) is not an integer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a screw mixer. The screw mixer of the present invention can be suitably used for crushing and discharging raw materials such as dewatered sludge cake.

[0002]

2. Description of the Related Art Gravel used as aggregate of ready-mixed concrete is generally mountain gravel, river gravel, or scrap stone at a quarry site. These gravel are wet-washed with water or the like at the stage of collection because soil is attached around individual stones. The washed-out soil is dewatered by a filter press machine to form a sludge cake.

[0003] This sludge cake is soft and has no utility value like sponge, and thus has been designated as industrial waste. If a hardened material such as quicklime can be uniformly mixed into the sludge cake, it can be regenerated as a civil engineering material, which is preferable from the viewpoint of resource saving and environmental protection.

[0004]

However, since the sludge cake has a high viscosity and the individual particles adhere to each other, it is difficult to finely crush and mix the hardened material uniformly. For example, when trying to crush the sludge cake with a known mixer, the sludge cake is circumscribed around the blades of the mixer and hinders the rotation of the blades. Therefore, an object of the present invention is to provide a screw mixer that can crush even a raw material having an extremely high viscosity such as a sludge cake.

[0005]

SUMMARY OF THE INVENTION In a mixer for crushing and discharging a raw material to be charged, a hopper having a charging port and a discharging port, a rotatable fixed inside the hopper, and a plurality of blades spirally mounted on a rotating shaft thereof. T _n (where n indicates the n-th number in the axial direction). The blades are provided with a screw shaft, and the blades have a mounting angle of the blade T _n when viewed from the rotation axis direction. The difference between the mounting angle of the blade T _{n + 1} and θ
It is characterized in that it is attached to the rotating shaft in such a manner that (360 / θ) does not become an integer when it is expressed in degrees.

The operation of the present invention will be described in comparison with a case where the blade is attached to the rotating shaft in a relationship where (360 / θ) is not an integer. The blades are attached to a position closest to one end of the rotary shaft and the blade T _1.

[0007] For example, if the theta = 90, blades because attached helically to the rotation axis, T ₂ is with a twist of T ₁ and 90 degrees far from the end of the rotating shaft than T ₁ Installed. T ₃ 180 more distant position
It is attached with a degree of twist. T ₄ is further apart 270 degrees (i.e., -90 degrees) is attached with a twisting of. Then, complete rotation in T _5, overlapping the T ₁ as viewed in the axial direction. That is, when θ = 90, the plurality of blades overlap on the same line every four rows when viewed in the axial direction. Therefore,
For example, assuming that a total of 88 blades are attached to one rotation shaft, 22 blades overlap each other when viewed in the axial direction. In this state, when a raw material such as a sludge cake is charged and the mixer is driven, a load is simultaneously applied to the 22 blades, so that the blade may not rotate or a driving source such as a motor may seize. θ = 12
If it is set to 0, every three rows overlap on the same line, and 29 blades overlap in the axial direction.

On the other hand, if θ = 100, T ₁₉
In finally it overlaps with T _1. That is, they overlap on the same line only every 18 columns. Therefore, even if 88 blades are attached to one rotating shaft as described above, the number of blades to which a load is simultaneously applied when the raw material is supplied and the mixer is driven is only five. For this reason, the load applied to the drive source is 5/22 when θ = 90 and 5/29 when θ = 120, and the rotation of the rotating shaft is prevented or the drive source is overloaded. No.

It is desirable that θ is set to be larger than 90. This means that even when θ is smaller than 90, it is possible to select a value of θ such that the number of blades overlapping on the same line is reduced, but the blades of adjacent rows are too close to each other, and the effect of the present invention is poor. Because it becomes. Further, it is preferable that a plurality of the screw shafts are fixed in parallel. This is because the raw material can be crushed by sandwiching the raw material between the blades of one screw shaft and the blades of the other screw shaft.

It is preferable that the hopper has a bottom, and a discharge port is provided in a part of the bottom, and the position of the input port and the position of the discharge port are shifted in the rotation axis direction in plan view. When the input port and the discharge port are overlapped in a plan view like a general hopper, the input raw material is only broken by the blade while passing through the screw shaft by its own weight. On the other hand, if the two ports are displaced from each other in the rotation axis direction in plan view, the raw materials can be crushed while being sent in the rotation axis direction.

As described above, when the two ports are shifted from each other in the direction of the rotation axis, it is preferable to devise the shape and arrangement of the blades as follows so that the raw material can be further finely ground.
That is, when T = ₁ is a blade attached to the end farthest from the discharge port and _Tm is a blade attached to the opposite end when n = ₁ to _m , T1 to _Tm-1 and the raw material without overlapping the discharge opening is curved to be sent toward the discharge port, T _m is to a mirror image arrangement with either the T ₁ of the T _m-1 in plan view. Since there is no outlet directly below the T ₁ of the T _m-1, put raw material is not able to fall immediately outlet hit from T ₁ to T _m-1, while being fed toward the discharge port each Crushed with feathers. Then, when it comes above the outlet, it hits _Tm . Since _Tm has a mirror image arrangement with the other blades, the raw material attempts to return in the reverse direction there, collides with the raw material sent in the forward direction, and falls to the discharge port.

[0012]

Embodiments of the present invention will be described with reference to the drawings. 1 is a plan view showing the screw mixer of the embodiment, FIG. 2 is a sectional view taken along the line XY of FIG. 1, and FIG. 3 is a left side view. The screw mixer 1 is connected to a hopper 2 which is opened so as to expand upward, two screw shafts 3 fixed in parallel to a lower end inside the hopper 2, and an end of the screw shaft 3 outside the hopper 2. And a motor 4 for driving the screw shaft 3 to rotate.

The hopper 2 has an input port 21 at the upper end, and has an L-shape in front view in which only a mounting portion of the screw shaft 3 projects toward the motor 4 in the axial direction. The discharge port 22 is provided on the lower surface of the protrusion. Each screw shaft 3 has 41 sheets at equal intervals spirally from the vicinity of the end opposite to the motor 4 to a position near the discharge port 22, and one near the end of the motor 4 for a total of 42 sheets. Are mounted. For convenience, the blades are numbered T ₁ , T ₂ ,... T _{42 in} order from the blade farthest from the outlet 22. The blade 5 has a curved spatula shape having a maximum width of 40 mm and a maximum thickness of about 9 mm, and its tip slightly faces the discharge port 22. However, only the T ₄₂ is reversed, i.e., are arranged with either a mirror image of the relationship of T ₁ through T _41. And T
_n and T _{n + 1} (n is an integer of 1 to 40) are attached with an angle difference of 100 degrees when viewed from the axial direction. Therefore, the overlap with T ₁ in the axial direction is caused by T ₁₉
And _T37 only.

The screw mixer 1 operates as follows. When the motor 4 is driven, the left one of the two screw shafts 3 rotates clockwise and the right one rotates counterclockwise when viewed from the motor 4. In this state, the sludge cake is charged from the charging port 21. Introduced sludge cake, per the two screw shafts, and sent with crushed cut with blades of T ₁ through T ₄₁ spirally toward the outlet 22. And finally, T42 is hit. T ₄₂ is T ₁ ~T ₄₁
Has a mirror image arrangement, and the crushed pieces of the sludge cake striking it collide with the crushed pieces sent in the forward direction in an attempt to be returned in the reverse direction, and fall into the discharge port 22.

In this way, the sludge cake which has been a large lump is finely crushed and conveyed to the next step by a conveyor or the like. Since it is finely crushed, it is easy to uniformly mix it with a hardened material such as quicklime. Therefore, the sludge cake that was considered only as industrial waste can be reused.

In the above-described embodiment, the rotation directions of the two parallel screw shafts are inwardly rotated so that the sludge cake passes between the screw shafts. However, the arrangement of the left and right screw shafts is exchanged. The rotation directions may be mutually outward. Which one to choose depends on the properties of the sludge cake.

[0017]

As described above, according to the screw mixer of the present invention, even a material having an extremely high viscosity can be finely crushed, which is useful in various fields of material processing.

[Brief description of the drawings]

FIG. 1 is a plan view showing a screw mixer of an embodiment.

FIG. 2 is a sectional view taken along line XY of FIG.

FIG. 3 is a left side view showing the screw mixer of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw mixer 2 Hopper 21 Inlet 22 Outlet 3 Screw shaft 4 Motor 5 Blade

Claims (5)

[Claims] 1. A mixer for crushing and discharging an input raw material, comprising: a hopper having an input port and an output port; and a rotatable fixed inside the hopper, and a plurality of blades T _n (n) spirally mounted on a rotation shaft thereof. Indicates an n-th one counted in the axial direction.), And the blades are blades Tn when viewed from the rotation axis direction.
A screw mixer, wherein (360 / θ) is not an integer when the difference between the mounting angle of the blade _{Tn + 1} and the mounting angle of the blade T _{n + 1} is θ degrees. 2. The screw mixer according to claim 1, wherein said θ> 90. 3. The screw mixer according to claim 1, wherein a plurality of the screw shafts are fixed in parallel. 4. The hopper has a bottom, a discharge port is provided in a part of the bottom, and the position of the input port and the position of the discharge port are shifted in the direction of the rotation axis in plan view. 3. The screw mixer according to any one of 3. Wherein said blade T _n is the n = vanes attached to T ₁ to the end of the farthest from the discharge port in 1 to m, vanes attached to T _m at the opposite end At this time, T ₁ to T _m-1 do not overlap with the discharge port in plan view and are curved so that the raw material is sent toward the discharge port, and T _m is T ₁ to T _m-1.
5. The screw mixer according to claim 4, which is in a mirror image arrangement with any one of the above.