JP2740937B2 - Lining liner for twin-screw kneading mixer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liner for a twin-screw kneading mixer for adjusting aggregates such as dams.

[0002]

2. Description of the Related Art For high-rise buildings such as buildings, roads, bridge bases, dams and seawalls, etc., cement and aggregate are mixed and adjusted into a slurry, which is poured into a predetermined formwork to form a desired shape. The process of forming a concrete skeleton is an important operation that accounts for a large proportion in each industrial field. Among them, depending on the purpose of use of the structure to be molded, unlike other general structures, it is possible to guarantee a high level of fluidity (workability) especially during pouring and physical properties of concrete after solidification. Sometimes it is absolutely necessary. For example, concrete skeletons that form various dam dams are planned on the assumption that they will function almost permanently once they are constructed, and the static pressure that they carry is extremely large. It is much better than general structures,
And its advantage must last long without losing its edge.

[0003] In order to realize such a concrete body, it is naturally necessary to optimize the mixing ratio of cement, aggregate, moisture and other additives, and to properly mix the mixing components. In other words, for general concrete adjustment, if the mixing components are mixed with a single-shaft tilting mill such as a ready-mixed mixer truck, the purpose can be fully satisfied, and the strength regulations for building construction and road laying can be passed. For a high-strength concrete molding material such as the one described above, it is far from a mere mixing level to a desired level, and the application of a mixer capable of exhibiting a special kneading action is required as an essential condition.

[0004] At present, construction of a large-scale dam of the top class requires RCD (Roller Compacted Dam).
The aim is to increase the amount of concrete poured by using the concrete method and significantly shorten the construction period, to increase the maximum size of the aggregate to 150 mm, and to forcibly knead it to reduce the green cutting power more than before. Is the latest technology. As kneading for dam concrete,
DM (Double Mixing) is recommended as appropriate,
In concrete that has been kneaded with the optimal amount of primary water, highly viscous cement paste adheres and forms shells around the aggregates.After that, even if secondary water is added and forced kneading continues, the shells do not disappear. The remaining focus is on the characteristic that a homogeneous and fluid concrete can be obtained. As a result, the pumpability and the strength after hardening due to homogenization are improved as concrete for dams, and a highly reliable and robust concrete skeleton is constructed.

FIG. 7 is a perspective view illustrating a two-shaft forced kneading mixer, in which a plurality of blades 4 respectively fixed to two rotating shafts 3 rotate in opposite directions to each other and are charged into the casing 1. The conventional mill is just a mixture, because it vigorously stirs the cement, moisture, aggregates and other additives and forcibly kneads the charge between the blades and the inner surface of the casing. On the other hand, the present apparatus realizes a much higher level of uniform homogenization of the slurry, and forms the basis of the characteristic of greatly improving the strength after solidification.

However, in order to knead the fluid thus forcibly charged, the kinetic energy of the frictional sliding between the rotating blade and the inner surface and the side surface of the casing increases by orders of magnitude more than before. In particular, it is unavoidable that the abrasion wear effect accompanying the rubbing of the inner surface and the side surface of the casing is extremely large. Taking this point into consideration, the casing of the twin-screw forced kneading mixer has a liner 2 with wear resistance attached to its inner surface without exception as shown in FIG. 8, and if the liner is worn, only the liner is used. They have been replacing them with new ones to prevent damage from wear to the casing itself. in this case,
Since it is premised on attachment and removal, the lining liner is divided into a size that can be easily updated on both the inner surface and the side surface, and bolts penetrating the casing are fastened outside the casing and attached to the inner surface and side surfaces This is a general configuration. As the material of the wear-resistant lining liner, high chromium cast iron, for example, 3% C-27Cr cast iron, a press-formed product, a processed product by a bending machine, or the like is used.

[0007] In contrast to the conventional technology of manufacturing the lining liner itself with a predetermined material, the remarkable progress of the welding overlay technology in recent years has shown great power in this field. The results have been greatly extended. That is, in the case of a single liner liner, there is a limit to the enhancement of the wear resistance, and if a material having a higher hardness is applied to further seek the wear resistance, the brittleness also increases almost in proportion. Eventually, cracking, breakage, and drop-off phenomena occur, which may cause damage to the casing body. Dam dam concrete contains a larger aggregate than normal construction, so if a brittle material is subjected to a local impact, it will easily break and fall off unexpectedly. Is often an experience. On the other hand, if a tough material such as mild steel is used as a base material and a metal material with high wear resistance is welded on it as a base material, the surface of the lining liner, which faces wear conditions, has extremely high wear resistance. Wear can be prevented from progressing, and the lining liner itself is fastened to the casing using a base material such as mild steel, so there is no danger of breaking or falling off even if there is some shock or vibration. It is evaluated that the effect of significantly extending the life of the liner was obtained.

[0008]

It is an indispensable requirement for the continuous use of equipment to continuously improve the extended service life of continuously used equipment. Although it is a liner that has a layer of hardfacing layer on the base material and has contributed to the improvement of maintenance that has never been considered before, a detailed examination does not mean that there is still no room for improvement. FIG. 9 shows a liner 2a attached to a conventional twin-screw kneading mixer casing 1a, which is a mild steel material (SS400) having a thickness of 9 mm.
And a hardened layer 22a of a 6 mm-thick high-hardness metal on the base material portion 21a. The figure mainly shows the joints where the lining liners 2a are adjacent to each other. The surface (wear surface) in the cross section immediately after the installation of a new product is indicated by a straight line (a), and the operation of the biaxial forced kneading mixer is described. The surface in the same cross section after the 3,000 m ³ treatment is shown by a curve (b). Further, the curve (c) shows the operation after 50,000 m ³ treatment, and the curve (d) shows the operation 750,000.
This shows the state after 000 m ³ treatment. Needless to say, this tendency is a characteristic that appears in almost all joints in the casing, and this local data shows unexpected problems hidden in the hardened hard facing type liner. It is actually displayed.

It is clear that if the wear progresses to the state shown by the curve (d) in the figure, the progress of the wear increases at once and reaches the casing itself in a short time. In other words, the wear surface that occupies the main part of the lining liner exhibits the expected wear resistance, and the high wear resistance unique to the overlay metal is fully exhibited, and the progress of wear is extremely slow and the operation time is reduced. Although it progresses only gradually with accumulation, it is found that the joint portion is much more abraded than the other surfaces. Although it has already been mentioned that the functional feature of the twin-screw kneading mixer is to strongly knead the charged materials, from the standpoint of equipment, especially the lining liner that comes into contact with these flowing materials on the inside and side surfaces. if you see,
This surface is constantly loaded with the dynamic energy of the material clamped between the rotating blades. This kinetic energy passes in a steady state to the smooth wear surface of the lining liner, but a minimum of 2-3 m at the joint
Since it is necessary to provide an air gap of m, the movement of the flowing material suddenly stops on this line, and the friction coefficient inevitably increases suddenly from the steady value up to that point. Since the fault is suddenly opened like a narrow groove on a smooth surface, it is natural that the friction condition changes suddenly. In the actual measurement, the coefficient of friction is 0.4 on the normal surface of the lining liner 2, while
It has been confirmed that the joint portion suddenly changes from about 0.4 × √2 to about 0.4 × √3. Because of the remarkable local level of wear, the wear of the joint always precedes the other surface, the separation is accelerated with time, and the build-up hardened layer 22a is completely consumed by the curve (C). After that, a large difference in wear resistance between the constituent metal of the build-up hardened layer 22a and the mild steel material is reflected as it is, and partial deep depressions are formed everywhere in the lining liner as shown by the curve (d). It will do.

When the wear progresses in the state of the curve (d), the wear of the base material is not only abruptly advanced to the main body of the casing at once, but also has an unfavorable influence on the operating conditions themselves. In other words, since the inner surface facing the rotation of the blades retreats locally and the difference in the distance that sandwiches the flowing material becomes a surface scattered like a mesh, the strong force of the essential twin-screw kneading mixer is essential. Variations also appear in the kneading action, which is a factor that hinders the production of a completely homogenized and powerful slurry. As a result, the quality of the slurry becomes uneven, and it is difficult to wipe out concerns about negative effects such as fluidity, strength after solidification, and temporal variations in physical properties. In addition, the unstable flow not only deteriorates the kneading action, but also increases the necessity of complicated and complicated maintenance such as a gradual increase of the energy consumption unit and a decrease in the function of the device due to mechanical fine vibration.
It is difficult to avoid secondary adverse conditions such as increased burden on workers and invisible decrease in productivity.

In order to solve the above-mentioned problems, the present invention selectively reinforces, in particular, a portion where the progress of wear is selectively severe so as to synchronize the divergence of the progress of wear as much as possible. An object of the present invention is to provide a lining liner of a twin-screw forced kneading mixer in which the useful life of the lining liner as a whole is greatly extended and a stable kneading action is always maintained.

[0012]

The lining liner 2 of the twin-screw forced kneading mixer according to the present invention comprises a lining liner 2 divided and attached to the inner peripheral surface and side surfaces of a casing 1 of the twin-screw forced kneading mixer. The liner 2 is composed of a base material portion 21 of ordinary steel and a build-up hardened layer 22 in which a high-hardness metal having a thickness t ₂ is multi-layered, and at least one side of an end face where the liners 2 are connected to each other is formed of a base material. Part 21
Through a step 23 formed by an inclined surface from the thin base material portion 24
The reinforcing end portion 20 is formed on the thin base material portion 24 by the thick build-up hardened layer 25 in which a high-hardness metal is multi-layered up to the same surface as the build-up hardened layer 22. The above problem was solved by setting the thickness t ₃ and the width L of the hardened layer 25 in the range of t ₃ ≧ (√2 to √3) t ₂ L ≧ (√2 to √3) t ₂ .

[0013]

1A and 1B are cross-sectional views showing an embodiment of the present invention. In the drawing, below the liner 2 is a base material portion 21 made of mild steel such as SS material, the cross-sectional thickness of which is t ₄ on the main wear surface, and the cross-sectional thickness is provided at the end where the liners 2 are adjacent to each other. It has a t ₁ thin preform 24 is thin enhanced end 20. Base material 21 and thin base material 2
4 is formed by a step 23 of an inclined surface, and the inclination angle θ is preferably formed at 30 to 45 degrees. The lower end line of the step, that is, the width of the thin base material portion 24 is L.
Is represented by On the SS material, the thickness for the wear surface t ₂ buildup cured layer 22, the thickness t ₃ thicker buildup hardened layer 25 is formed in the reinforced ends, the thickness of the mild steel material and the overlaying The sum of the thicknesses of the abrasion-resistant metal thus obtained is naturally equal to the total thickness t of the lining liner 2 at any position. t ₃ and t ₂
The limitation of the above relationship is that the difference between the coefficient of friction between the joint surface and the general wear surface for the lining liner obtained by actual measurement is considered as a factor that governs the strength of the wear action,
It is based on the fact that the area around the joint is set so as to remain without being exhausted until the general wear surface is consumed by wear. Further, as to the inclination angle θ of the step, it is most appropriate to follow an angle customarily used in a general welding groove, and therefore, it is applied. As a result, as indicated by the curve (e) in the figure (B), the progress of the wear of the lining liner 2 proceeds at a balanced and slow speed as a whole,
When the build-up hardened layer 22 occupying the main part of the lining liner withstands a long operation and finally wears out until the end of its life, the joints that have previously undergone abrasion and regression also have a thicker hardened layer. The coordinating action of exhausting and ending the mission at the same time is exerted.

If the wear resistance of each part of the wear surface is improved and the growth of unevenness due to deep local wear is suppressed, there is no doubt that it is effective for the kneading action of concrete. Even for the RCD method of dams that mix relatively large aggregates,
A high-viscosity cement film is uniformly formed around the entire periphery of the aggregate, and has an effective action for adjusting concrete having high fluidity and high strength after solidification.

[0015]

FIG. 2 is a front view (A) and a cross-sectional view showing an embodiment of the present invention. FIG. 3 shows a positional relationship when the liner 2 of the embodiment is applied to a twin-screw forced kneading mixer. It is a part of longitudinal cross-sectional view illustrated. A lining liner 2 is attached to an inner peripheral surface of a casing 1 constituting an outer shell, and a material charged between each surface and a blade 4 fixed to a rotating shaft 3 is pressed while flowing. Kneaded and finished as a highly homogenized fluid.

The lining liner which is attached in close contact with the cylindrical curved surface of the casing of the twin-screw kneading mixer is, of course, composed of an inner and outer surface having the same curvature as the curved surface. In the base material part, a required curved surface and a step are formed from an SS material having a high workability by a press or a bending machine, or a product having a curved surface and a step is obtained in an as-cast state using ordinary cast steel having excellent castability. It is more preferable that the material of the base material be freely selected from low alloy steels in consideration of mechanical properties in addition to the SS material. Whether the shape of the base metal part is to strengthen the entire circumference of the lining liner in response to the wear progress characteristics of the twin-screw kneading mixer, or whether it is kept only in one direction where the tendency is particularly severe, is recorded with the operation There is room for selection depending on the performance to be performed. FIGS. 4 (A-) and (A-) are unidirectional square liners, (B-) and (B-) are unidirectional rectangular liners, and FIGS. 5 (A) and (A-) are rectangular liners. (B-) and (B-) are examples of the omnidirectional type of the liner. FIGS. 6 (A) and 6 (B) show an example in which odd-shaped liners 2 for the casing side surface are arranged, and all the liners are strengthened at the ends of the entire circumference to prepare for abnormal local wear. is there.

As an example of the lining liner of the twin-screw forced kneading mixer which is currently in the mainstream and is movable, t _{1 of the} base material portion is 9 to 12 mm, and t ₂ of the hard facing layer 22 is ₆ to 7 m.
m, at t ₃ 8.5～10Mm about thick cladding hardened layer 25, the width L is made of 15～19Mm, Zen'nikuAtsu of t
Form a liner 2 of 15 to 19 mm.
This value is merely an example, of course, and is naturally changed if the size of the lining liner changes, but in any case, only the ratio of the build-up layer based on the difference in the friction coefficient is an essential requirement. Becomes The state of the surface of the lining liner which retreats with the progress of the operation in this embodiment is shown in FIG. 1B, and the consumption of the build-up layer ends at the stage of the 120,000 m ³ treatment of the curve (e). And wear rapidly progressed to 15
It is time to renew after reaching the curve (f) of the 3,000 m ³ treatment.

Although the construction of a hardfacing layer made of a high-hardness metal has made remarkable progress in recent years, proper selection of the technique is a great condition that determines the value of the present invention. Even though it is a weld overlay, the ultra-hard hardness overlay metal is not only excellent in wear resistance but also extremely brittle, so the overlay cannot easily withstand a slight impact and cracks. There is no change in the danger of exfoliation. However, this serious problem is described in Japanese Patent Laid-Open No.
This problem is basically solved by, for example, JP-A-71390. That is, in this prior art, the heat input J during welding is set to 2
000-6000 J / cm range (1 for normal semi-automatic welding)
Utilizing the idea that reverses the conventional wisdom of limiting the interlaminar temperature during welding to around 5,000 J / cm) and always limiting the interlayer temperature during welding to 300 ° C. or less, a fine crack perpendicular to the bead direction is formed in the weld metal bead. For example, C: 3.0-7.
0%, Si: 0.5 to 2.0%, Mn: 0.5 to 4.0
%, Cr: 20.0 to 35.0%, such as super-hard metal components having an Hv hardness exceeding at least 600 have been successfully accumulated on the base material as a stable overlay layer. is there.

[0019]

As described above, the present invention has a very long service life as compared with the prior art as a lining liner of a twin-screw forced kneading mixer, and it has been reported that it has more than doubled in trial tests in the field. Have been. The unique wear conditions associated with the use of this member are grasped, and the unique configuration of rational wear resistance matching that characteristic is evaluated to have led to this achievement. Not only is the direct benefit of simply reducing maintenance costs by extending the service life, but also the opportunity loss due to equipment stoppage during replacement, the reduction of the amount of work required for maintenance is large, the energy intensity is reduced, and daily life is reduced. Since the operation is always stable, it cannot be overlooked that the effect of maintaining the quality of providing evenly kneaded fluids without change can be provided even for concrete for dams containing a relatively large aggregate of aggregate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a reinforced end (A) and a process of wear (B) of the present invention.

FIG. 2 is a front view (A) and a cross-sectional view (B) of the embodiment.

FIG. 3 is a longitudinal sectional view of the same.

FIG. 4 is a front view (A-, B-) and a cross-sectional view (A-, B-) showing another two embodiments (A) and (B).

FIG. 5 is a front view (A-) of another two embodiments (A) and (B).
, B-) and cross-sectional views (A-, B-).

FIG. 6 is a front view (A) and a cross-sectional view (B) of another embodiment.

FIG. 7 is a perspective view showing the entire twin-screw kneading mixer.

FIG. 8 is a perspective view showing an attached state of the lining liner 2 in the biaxial forced kneading mixer.

FIG. 9 is a cross-sectional view showing a problem of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Lining liner 3 Rotating shaft 4 Blade 20 Reinforced end 21 Base material 22 Hard layer 23 Step 24 Thin base material 25 Thick hard layer

Continued on the front page (72) Inventor Shigeaki Sugioka 1-12-19 Kitahorie, Nishi-ku, Osaka-shi, Osaka Inside Kurimoto Ironworks Co., Ltd. Inside Kurimoto Ironworks Co., Ltd. (72) Inventor Shin Ikuta 1-12-19 Kitahorie, Nishi-ku, Osaka-shi, Osaka Inside Kurimoto Ironworks Co., Ltd.

Claims (1)

(57) [Claims] 1. A liner 2 divided and attached to an inner peripheral surface and a side surface of a casing 1 of a biaxial forced kneading mixer.
, The lining liner 2 is composed of a base material portion 21 of ordinary steel and a build-up hardened layer 22 in which a high-hardness metal having a thickness t ₂ is multi-layered, and at least one side of an end face where the lining liners 2 are connected to each other is at least one side. A thin base material portion 24 is formed from the base material portion 21 through a step 23 formed by an inclined surface, and a high-hardness metal is multi-layered on the thin base material portion 24 until the same surface as the build-up hardened layer 22 is obtained. The reinforced end portion 20 is formed by the thick build-up hardened layer 25, and the thickness t ₃ of the thick build-up hardened layer 25 is formed.
And width L, t ₃ ≧ (√2~√3) respectively t ₂ L ≧ (√2~√3) lining liner biaxially forced kneading mixer, characterized in that the range of t _2.