JPH0663447A - Screw conveyor - Google Patents

Abstract

PURPOSE:To obtain an assembly of a lining tile 10 and a chip preventing the lateral shift of the chip and the damage thereto due to an impact especially in the abrasion-resistant member of the leading end of the spiral blade of the screw conveyor for a decanter type centrifugal separator. CONSTITUTION:An assembly consists of a lining tile 10 desirably composed of the same material as a spiral blade and the chip 11 composed of an abrasion- resistant material fixed to the tile 10. A recessed part 12 is provided to the surface coming into contact with the chip of the lining tile on the side near to the center of rotation of the spiral blade and the protruding part 13 engaged with the recessed part is provided to the chip 11. The upper edge 13 of the protruding part has a protruding shape having a radius smaller than that of the circular arc centering around the center of rotation of the spiral blade and the peripheral surface thereof forms an obtuse angle with respect to the surface of the chip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw conveyor, and more particularly to an improvement of a wear-resistant member at a tip of a spiral blade of a screw conveyor of a decanter type centrifugal separator.

[0002]

2. Description of the Related Art In screw conveyors, especially screw conveyors of a decanter type centrifugal separator, it has been attempted to attach wear-resistant chips such as tungsten carbide and ceramics to the blade tips in order to reduce wear on the surface of the spiral blade. Has been done. Welding or adhering the tip directly to the blade has problems in terms of thermal influence on the tip, reliability of mounting, etc., and it is desirable to combine the mounting member and the chip made of the same material as the blade. A method of preparing a solid body and welding the mounting member to the blade has been proposed.

For example, in Japanese Utility Model Laid-Open No. 59-166852, a mounting member having an engaging portion with the tip is welded to the tip of the blade and the base of the tip to form a dovetail groove for mounting the tip, and then the tip. It has been proposed to attach the chip by inserting and engaging the engaging portion provided in the dovetail groove with the engaging portion. However, this method is difficult to manufacture because the two members need to be welded separately so as to form a dovetail groove having a correct size for the chip.

In Japanese Patent Publication No. 51-41707, this mounting member is formed as a backing tile, and it is proposed to braze or adhere parallel plate-shaped chips to the backing tile and weld the backing tile. ing. Further, in Japanese Examined Patent Publication No. 59-15032, in order to prevent the chips from falling off due to the brazing or peeling of the adhesive, a dovetail-shaped engaging groove is provided in the backing tile at a right angle to the centrifugal force. The engaging portion provided on the chip is inserted into and engaged with the dovetail groove. However, in this structure, it is necessary to provide an engaging portion to the dovetail groove that extends at an acute angle from the chip body, and stress concentration occurs here, so not only when handling the chip individually but also after mounting it on the screw body. However, when the chip is subjected to impact, such as when the screw body is placed on the floor during disassembly or during manufacturing, this part may be damaged in the chip having low toughness. Further, in the case of manufacturing by precision casting, there is a problem that a sag occurs at an acute angle portion and a repair work is indispensable for accurate mounting. Further, in the type in which the engaging portion is inserted into the dovetail groove from the side, when a force that causes lateral displacement of one chip acts, displacement of adjacent chips one after another may occur. There was a problem.

[0005]

SUMMARY OF THE INVENTION The present invention seeks a structure for obtaining a backing tile and chip assembly that is easy to manufacture and does not suffer from the above problems.

[0006]

[Means for Solving the Problems] To achieve the above object,
The backing tile and tip assembly of this invention comprises a backing tile, preferably of the same material as the spiral blade, and a tip of wear resistant material affixed to it, which abuts the tip of the backing tile. A concave portion is provided in the lower part of the surface (the side close to the rotation center of the spiral blade), and a convex portion that engages with this concave portion is provided on the tip side, and the upper edge of the convex portion is centered on the rotation center of the spiral blade. It is characterized in that it has a convex or concave shape with respect to the arc or its chord, and the peripheral surfaces of the convex portion and the concave portion form an obtuse angle with respect to the chip surface.

[0007]

In the cross-sectional view shown in FIG. 1, the backing tile 1 and the chip 2 are in flat contact with the upper portions 1'and 2 ', and the lower portion is provided with the concave portion 3 in the backing tile 1 and the chip 2
The lower convex portion 4 is engaged, and the entire contact surface is fixed with an adhesive or the like. This assembly is welded to the spiral vane edge at the 1 "'part. Then, as shown in FIG. 2, the upper edges 3 ″, 4 ″ of this engaging portion are convex with respect to the arc 5 centering around the rotation center of the spiral blade, so that centrifugal force due to rotation causes By pressing the peripheral surface 4 ′ against the peripheral surface 3 ′, the chip 2 is held so as not to be laterally displaced with respect to the backing tile 1. As described above, in order to provide the engagement portion with the function of preventing the lateral displacement, the upper edges 3 "and 4" of the engagement portion are formed into a straight line 5'perpendicular to the radius from the rotation center of the spiral blade. On the other hand, it may be concave.

The peripheral surface 3'of the concave portion 3 and the convex peripheral surface 4'that abuts against the peripheral surface 3'form an obtuse angle .theta. For this reason, the impact resistance strength of the peripheral portion of the chip convex portion 4 becomes large, and cracks during manufacturing or during disassembly can be prevented,
The convex portion 4 can be easily pushed into the concave portion 3 even during assembly. Abutment surface 1 "" of the backing tile 1 to the screw
Forms an angle ψ with respect to the chip surface 2 ′ as shown in the figure, and the chip 2 is attached to the screw in a form tilted forward by the angle ψ. Therefore, (θ-90 °) <
If ψ, the peripheral surfaces 3 ′ and 4 ′ are inclined so as to be deeper with respect to the horizontal plane, and even if θ is an obtuse angle, no force is applied to the tip in the direction of detachment due to the centrifugal force.

[0009]

EXAMPLES Examples of the present invention will be shown below. Most simply, as shown in FIG. 3, the concave portion 8 of the backing tile 6 is circular, the convex portion 9 that engages with this is formed on the chip 7, and the concave portion 8 and the convex portion 9 are in the engaged state. The entire contact surface is adhered with an adhesive. In this case, since the peripheral surfaces 8 ′ and 9 ′ of the convex portion and the concave portion form an obtuse angle with the main body, the convex portion 9 can be easily formed into the concave portion 8 ′.
It can be pressed into and glued. Moreover, the relative displacement between the backing tile 6 and the chip 7 is
It can be prevented not only in the radial direction of the spiral blade but also in the circumferential direction, and the adhesion of the chip can be made strong.

In the second embodiment shown in FIG. 4, the upper edge 12 "of the recess 12 of the backing tile 10 and the upper edge 13" of the protrusion 13 of the tip 11 engaging with it are the center of rotation of the spiral blade. Is a circular arc with a radius smaller than the circle centered on the center of the chip. The centrifugal force applied to the peripheral surface of the circle can be dispersed over the entire engaging portion between the tile and the chip, and the centrifugal force acts to shift the chip 11 to the left and right. Prevent. Further, a side stopper 14 that engages with the side surface of the chip 11 is provided below the backing tile to prevent not only the lateral displacement of the chip 11 but also the rotational displacement thereof. Even in such a shape, the chips can be pressed and engaged with the backing tile from the upper surface by forming obtuse angles on the peripheral surfaces of the concave and convex portions.
Further, numeral 15 is a recess serving as an adhesive reservoir, which enables formation of a uniform thin adhesive layer on the contact surface between the backing tile 10 and the chip 11 in the periphery of the recess 15, thereby providing strong adhesive strength and corrosion resistance. Can be obtained.

In the embodiment shown in FIG. 5, the overall structure is almost the same as that of the previous embodiment, but the engaging portions 12 "and 13" of the tile and the tip are formed in a circle centered on the rotation center of the spiral blade. It is concave from the chord, and even with such a shape, the action of holding the chip against the centrifugal force and the action of preventing the chip from shifting to the left and right are the same as in the previous embodiment. Although the side stopper 14 is short, its action is the same as that of the previous embodiment.

[0012]

Since the screw conveyor of the present invention has the above-mentioned structure, it is possible to prevent the chips from slipping side by side and increase the impact strength of the chips for each assembly of the backing tile and the chips. It was possible to obtain a highly practical product which can reduce the possibility of chip damage not only during manufacture but also during manufacture or disassembly.

[Brief description of drawings]

FIG. 1 is a sectional view showing the concept of the structure of a wear-resistant member of a screw conveyor according to the present invention.

FIG. 2 is a plan view showing the concept of the structure of the wear resistant member of the screw conveyor of the present invention.

FIG. 3 is a perspective view showing an embodiment of the screw conveyor of the present invention.

FIG. 4 is a perspective view showing another embodiment of the screw conveyor of the present invention.

FIG. 5 is a perspective view showing still another embodiment of the screw conveyor according to the present invention.

[Explanation of symbols]

1,6,10 Backing tile 2,7,11
Chips 3,8,12 Recesses in backing tiles 4,9,13
Tip protrusion 14 Side stop 15 Adhesive reservoir

Claims (3)

[Claims] 1. A backing tile and a chip made of a wear-resistant material fixed to the backing tile, wherein a recess is formed in a lower portion of a surface of the backing tile which is in contact with the chip (a side close to a rotation center of a spiral blade). The side is provided with a convex portion that engages with this concave portion, and the upper edge of the convex portion is an arc having the rotation center of the spiral blade as a center or a convex or concave shape with respect to its chord. The screw conveyor is characterized in that the screw is arranged at the tip of the spiral blade. 2. The screw conveyor according to claim 1, wherein the backing tile and the peripheral surface of the convex portion and the concave portion of the chip form an obtuse angle with respect to the chip surface. 3. The screw conveyor according to claim 1 or 2, wherein an adhesive reservoir is provided on a surface of the backing tile that contacts the chip.