JPS6234523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a twin-screw concrete mixer for mixing concrete raw materials.

A conventional mixer of this type is shown in FIGS. 1 and 2. In the figure, 1 is a casing, 2 and 3 are a pair of mutually parallel rotating shafts, 4 is a plurality of paddles attached to the rotating shafts 2 and 3, and each is a stirring blade fixed to the end of a long arm 5. 6, and a stirring blade 8 fixed to the tip of a short arm 7 facing the stirring blade 6. The inclination of the stirring blades of the paddles 4 and 4' of the rotating shafts 2 and 3 is such that when the paddles 4 and 4' rotate in the direction of the arrow in Fig. 2, while the raw materials are being stirred and mixed, the inclination of the stirring blades in the outer area of the casing is as shown in Fig. 1. The fluid flows in opposite directions along the opposing side walls of the casing as shown by the arrows, and in the center of the casing, the fluid moves toward the opposing rotating shafts by opposing rotating paddles, thereby performing a circular motion. Generally, in order to obtain good mixing in a short period of time, it is necessary to carry out such a circular movement powerfully at maximum travel speed. However, in this conventional mixer, the long-arm stirring blade 6 has a high circumferential speed and can exert a sufficient mixing effect, but the short-arm stirring blade 8 has a small peripheral speed, especially between the paddles. The mixing effect of the raw materials near the shaft surface was extremely small, as the mixing was carried out by movement due to the thrust of the axial component of the stirring blade 8 of the short arm. As the circulation movement of the raw materials near the rotating shaft is small, good mixing cannot be achieved in a short time, and the concrete deposits on the rotating shaft surface cannot be peeled off, so it takes time to clean after use. It was hot.

To compensate for this shortcoming near the rotating shaft, fill the raw material to the shaft center level or above.
During operation, a short stirring blade 8 is used to feed the raw materials over the top of the shaft and into the opposite rotational direction for stirring and mixing, but even with this method, a sufficient mixing effect cannot be obtained, and the bearing The disadvantage was that the seal was damaged early by the raw material.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a two-screw mixer for concrete that causes circulation movement of raw materials even near the rotation axis and exhibits a good mixing effect in a short time. .

In order to achieve the above object, according to the present invention, the shaft having the paddle is configured as an eccentric shaft eccentric to the rotation axis, and the paddle extending radially from the eccentric shaft is also arranged near the rotation axis. Good.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments.

3 and 4, 12 and 13 are a pair of parallel rotating shafts that are rotatably supported by the casing 11 and rotate in opposite directions as indicated by arrows in FIG. 4. According to the invention, axles 14 and 15 with paddles are connected to crank arms 16 and 17, respectively.
The eccentric shaft 15 is configured as an eccentric shaft that is eccentric with respect to the rotation axis, and the phase of the eccentric shaft 15 is delayed by 135 degrees in the rotation direction with respect to the eccentric shaft 14. Each of the eccentric shafts 14 and 15 has an arm 18......22.
and 18'...22' are arranged in the circumferential direction, and stirring blades 23...27, 2 are provided on each arm.
3'...27' are provided, and stirring blades 28, 29 and 2 are also provided at both ends of the eccentric shafts 14, 15, respectively.
8' and 29' are attached. The inclination of the stirring blades 23...27 of one pair of eccentric shafts 14 is such that the stirring blades leading in the rotation direction push the raw material in the direction of arrow A in FIG. , the pushed raw material is further pushed in the direction of the arrow A. In addition, stirring blades 30, 3 are provided at the extreme end in the direction of movement of the raw material.
1 is provided, and the inclination of this stirring blade is such that it pushes the raw material in the opposite direction to the arrow A together with the stirring blade 29, providing resistance to the pushed raw material and pushing it in the direction of the eccentric shaft 15 on the opposite side. Performs a feeding action. Stirring blade 2 of eccentric shaft 15
3'...27' has an inclination such that the raw material fed from the eccentric shaft 14 side is pushed in the direction B opposite to the direction A. These stirring blades 23'...
...27' and 28', 30', 31' cause a circulating movement of the raw material in the casing.

Furthermore, the present invention provides two of the plurality of stirring blades.
7 and 27' project from the eccentric shafts 14 and 15 through arms 22 and 22', respectively, toward the center of the rotating shaft, and these stirring blades are connected to the arms 18 and 18'.
At the same time, agitation is performed near the center of the rotating shaft.

Furthermore, mixing vanes 32, 32' are attached to the eccentric shafts 14, 15, respectively, on their surfaces facing in the direction of rotation.

The inclinations of these mixing blades 32, 32' are adapted to push the raw material in the A direction and the B direction, respectively, and cause it to circulate. These mixing blades 32,
32' allows the eccentric shafts 14, 15 to exert the same mixing effect as the above-mentioned stirring blade.

Briefly describing the operation of the two-shaft mixer configured as described above, the eccentric shafts 14 and 15 having a large number of stirring blades and mixing blades are mutually rotated by the rotating shafts 12 and 13 that rotate in opposite directions. It rotates in opposite directions, with the raw materials being stirred and mixed by the respective stirring impellers, eccentric shafts and mixing impellers, while in the outer region of the casing the raw materials are forced in mutually opposite directions A and B along the opposite side walls of the casing, and in the center of the casing. In this case, the raw materials are moved across the casing centerline to opposite sides by stirring blades rotating in opposite directions. In this way, all rotating parts, including the eccentric shaft, perform a mixing action and a large circular movement of the raw material is obtained.

In the present invention, since the shaft having the paddle is eccentric to the rotational axis and configured as an eccentric shaft, the eccentric shaft itself can perform the mixing action. Furthermore, since the paddles extending radially from the eccentric shaft are arranged near the rotation axis, the raw materials can be stirred and mixed near the rotation axis, which was a weak point of conventional two-screw mixers. In this way, all the rotating parts including the eccentric shaft and the paddle perform the mixing action of the raw materials, so that a large circulation movement is induced and good mixing is obtained in a short time. In particular, since the paddle near the rotation axis also circulates the raw materials near the rotation axis, good mixing can be obtained even when the mixer is operated with the filling level of the mixed raw materials lower than the rotation axis level. Therefore, damage to the rotary bearing seals is significantly reduced and maintenance becomes easier. Furthermore, since the circulation movement is large, there is less material adhesion to the eccentric shaft, and there are advantages such as easy cleaning.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional two-shaft mixer for concrete, FIG. 2 is a cross-sectional view of the mixer shown in FIG. 1, and FIG. 3 is a plan view of a two-shaft mixer for concrete according to the present invention. FIG. 4 is a cross-sectional view of the mixer of FIG. 3. 11... Casing, 12, 13... Rotating shaft,
14, 15... Eccentric shaft, 23, 23', 24, 2
4', 25, 25', 26, 26', 27, 27',
28, 28', 29, 29', 30, 30', 3
1, 31'... Stirring blade, 32, 32'... Mixing blade.

Claims (1)

[Claims] 1. A two-shaft mixer for concrete having two mutually parallel shafts rotatably disposed in a casing and a plurality of paddles attached to each shaft, which includes a paddle. A two-shaft mixer characterized in that the shaft is configured as an eccentric shaft eccentric to the rotational axis, and paddles extending radially from the eccentric shaft are also arranged near the rotational axis. 2. The two-shaft mixer according to claim 1, wherein the mixing blade is attached to the surface of the eccentric shaft facing the rotation direction at an angle with respect to the axis.