JPH0663448A - Screw conveyor - Google Patents

Abstract

PURPOSE:To obtain an assembly of a lining tile and a chip preventing the lateral shift of the chip and the damage thereto due to an impact and capable of easily being produced 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:A recessed part 12 is provided to the lower part of the surface coming into contact with a chip 3 of a lining tile 10 (on the side near to the center of rotation of a spiral blade) and the protruding part 4 engaged with the recessed part is provided to the chip 3. The side stoppers 2 ' engaged with both sides of the protruding part of the chip 3 to prevent the lateral shift of the chip 3 are provided to the recessed part 2 of the lining tile on both sides thereof. The upper edge of the protruding part 4 of the chip 3 desirably has a protruding or recessed shape with respect to the circular arc centering around the center of rotation of the spiral blade or the chord thereof. Further, the peripheral surface of the recessed part 3 of the lining tile 10 and that of the protruding part 4 of the chip 3 desirably have an obtuse angle with respect to the surface of the chip 3.

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 is problematic in terms of thermal influence on the tip, reliability of attachment, etc., and it is desirable to attach the tip to the attachment member made of the same material as the blade and the tip. It has been proposed to prepare an assembly and weld this mounting member to the blade.

In Japanese Utility Model Laid-Open No. 59-166852, for example, a mounting member having an engaging portion for 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. It has been proposed to attach the chip by inserting and engaging an engaging portion provided on the chip into the dovetail groove.

In Japanese Examined Patent Publication No. 59-15032, the mounting member is formed as a backing tile, and a dovetail-shaped engaging groove is formed in the backing tile to prevent the chip from falling off due to brazing or peeling of adhesive. It is provided so as to be substantially perpendicular to the centrifugal force, and the engaging portion provided on the chip is inserted and engaged in this 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.

In JP-A-51-86870, a chip mounting base extends in the radial direction of a spiral blade and is mounted so as to form a dovetail groove inclined so as to be slightly tapered, and the chip is mounted in this dovetail groove. It is proposed to insert and fix the blade from the rotation center side. In this configuration, the chip is not laterally displaced, but the amount of protrusion of the chip changes greatly due to a dimensional error between the dovetail groove and the engaging portion of the chip, and it is difficult to improve the mounting accuracy.

[0006]

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.

[0007]

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

[0008]

EXAMPLES Examples of the present invention will be shown below. Most simply, as shown in FIG. 1A, a plan view, FIG. 1B is an end view taken along line AA, and FIG. 1C is an end view taken along line BB.
The convex portion 4 of the chip 3 is engaged with the concave portion 2 of the backing tile 1. The entire contact surface may be adhered with an adhesive while the concave portion 2 and the convex portion 4 are engaged, but if the convex portion 4 forms an acute angle θ with the chip 3 as shown in the figure, this The engagement of both can be maintained only at the joint. Further, the upper edge 2 ″ of the concave portion 2 of the backing tile 1 and the upper edge 4 ″ of the convex portion 4 of the tip 3 which engages with the backing tile 1 are circular arcs having a radius smaller than a circle centered on the rotation center of the spiral blade. The centrifugal force applied to the peripheral surface can be dispersed over the entire surface of the engaging portion between the tile and the chip, and the action of the centrifugal force prevents the chip 11 from shifting to the left and right, and the side wall of the recess 2 of the backing tile 1. Along with 2 ', the lateral displacement of the chip 3 is suppressed. This embodiment does not require any special measures for joining the backing tile and the chip and the mounting of the chip is very simple. However, the tip 3 is formed of a material having low toughness, such as tungsten carbide and ceramics, which has high wear resistance, but the chip 3 is likely to be damaged due to the notch effect generated at the acute angle portion.

In the second embodiment shown in FIG. 2, in order to avoid the notch effect of the first embodiment, the peripheral surfaces 2 "and 4" of the convex portion and the concave portion form an obtuse angle θ with the main body. . The contact surface 1 "" of the backing tile 1 with respect to the screw has an angle ψ with respect to the chip surface 3 as shown in the drawing, and the chip 3 should be attached to the screw by tilting forward by the angle ψ. Becomes Therefore, if (θ-90 °) <ψ, the peripheral surfaces 2 ″ and 4 ″ are inclined so as to be deeper with respect to the horizontal plane, and even if θ is an obtuse angle, the tip is detached by centrifugal force. Although it does not receive force, it is desirable to bond them with an adhesive, just in case. In addition, since the convex portion 4 can be easily pushed into the concave portion 2 because of the obtuse angle, the adhesive strength is generally the same as that of the adhesive itself when the adhesive layer becomes thicker. Because,
It should be as thin as possible. However, in the case of whole surface adhesion, if the thickness of the adhesive layer is made thin, there are some portions that are not sufficiently wetted by the adhesive, which may lead to a decrease in adhesive strength and corrosion from the gap. In this embodiment, since the adhesive reservoir 5 is provided as a recessed portion of the backing tile 1, when the backing tile 1 and the chip 3 are strongly pressed, excess adhesive flows into the adhesive reservoir 5 and A thin and strong bond is guaranteed around.

In the third embodiment shown in FIG. 3, side stoppers 14 are provided on the lower part of the backing tile to engage not only the convex portions of the chip 11 but also all the side surfaces thereof, so that the lateral displacement and rotational displacement of the chip 11 can be prevented. Prevent. 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. In addition, 15 is a dent that serves as an adhesive reservoir,
This makes it possible to form a uniform thin adhesive layer on the contact surface between the backing tile 10 and the chip 11 around the recess 15,
It becomes possible to obtain strong adhesive strength and corrosion resistance.

[0011]

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 plan view and a sectional view showing an embodiment of a wear resistant member of a screw conveyor of the present invention.

FIG. 2 is a plan view and a cross-sectional view showing a second embodiment of the wear resistant member of the screw conveyor of the present invention.

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

[Explanation of symbols]

1,10 Backing tile 2,12 Recessing tile of backing tile 3,11 Chip 4,13 Projection of chip 2 ', 14 Side stop 5,15 Adhesive reservoir

Claims (4)

[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 screw conveyor is characterized in that a convex portion that engages with this concave portion is provided on the side, and side stoppers that engage with both convex portions of the chip are provided on both sides of the concave portion of the backing tile. 2. The upper edge of the convex portion of the tip has an assembly having a circular arc centered on the rotation center of the spiral blade or a convex or concave shape with respect to the chord of the circular arc at the tip of the spiral blade. The screw conveyor according to claim 1, characterized in that 3. 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. 4. The screw conveyor according to claim 1, wherein an adhesive reservoir is provided on a surface of the backing tile that contacts the chip.