CN100455363C - Discrete stone classification device - Google Patents

Abstract

The invention discloses a discrete stone grading device. The vibrating screen comprises a vibrating motor which drives a screen box frame and a plurality of layers of screen meshes to vibrate in a reciprocating mode, wherein the vibrating motor is a vibration source, the screen plates of the plurality of layers of screen meshes are of a curve structure, and the screen holes on the screen plates are of an inverted cone structure. The invention designs the vibrating screen with multiple layers of screen surfaces, the screen holes are in an inverted cone structure, and the feeding end of each screen hole is provided with a conical bulge, so that when the vibrating screen is used for grading stones, materials cannot block the screen holes; due to the adoption of the curved sieve plate structure, the screened materials cannot be stacked together and have the function of dispersing stones, so that the screening efficiency is improved by about 30-50% compared with that of a common vibrating screen. Meanwhile, the dispersing function reduces the abrasion of stones to the sieve plate, prolongs the service life of the sieve plate and reduces the replacement frequency of the sieve plate by 50 percent compared with a common sieving device; the frequency of the exciting motor is 0.9-1.1 times of the natural frequency of the multi-layer screen, and the exciting motor has the function of preventing screen holes from being blocked.

Description

Discrete stone classification device

technical field

The invention relates to a stone sieving and grading device, in particular to a sieving and grading device for hot aggregate grading treatment of asphalt mixing equipment.

Background technique

The working principle of the asphalt mixing plant is: cold aggregate (that is, stones of different specifications) is sent to the drying drum through the frequency conversion speed regulation belt, and after being heated and dried by hot air, it is transported to the tower. There is a screening above the tower. system, the heated stones are screened and graded here, and loaded into each hot aggregate silo, and then according to the requirements of the asphalt mixture formula, hot aggregates of different specifications are measured and mixed with a certain proportion of asphalt according to the proportion. Finally, the asphalt mixture is obtained.

In the original asphalt mixture mixing equipment, the screening and grading device used (Li Shikun. The development of asphalt mixture mixing equipment in my country. Road construction machinery and construction mechanization. 2003.06; Chen Qizong. The development of foreign asphalt concrete recycling mixing equipment. Construction machinery and Maintenance. 2000.10) is a vibrating screen with ordinary flat sieve plate and multi-layer screen structure. The sieve plate of the vibrating screen is made of steel wire mesh, and the shape of the sieve hole is rectangular, which is prone to blockage; the excitation frequency of the vibrating screen does not match the natural frequency of the screen, so there is no anti-blocking function; The flat sieve plate has no discrete effect, so the screening efficiency is low, and the wear of the stone on the screen is increased, so the life of the screening device is low; and the mechanical characteristics of the ordinary flat sieve plate structure are not good, so the screening device has a structure Unreliable, high maintenance costs and other issues.

Contents of the invention

The object of the present invention is to provide a discrete stone grading device for hot aggregate grading treatment of asphalt mixing equipment. The device has high structural strength, is not easy to be blocked by materials, has a long service life, high production efficiency and low maintenance cost.

The technical solution to realize the purpose of the present invention is: a discrete stone classification device, including a vibration motor that drives the screen box frame and the multi-layer screen for reciprocating vibration, the vibration motor is the vibration source, and the screen of the multi-layer screen is The plate has a curved structure, and the sieve hole on the sieve plate is an inverted conical structure. The front section of the multi-layer screen is arranged by the equal-thickness screening method, that is, the screen surface at the inlet is divided into two sections, and the first section of the screen surface The inclination angle is 30-40 degrees, and the inclination angle of the second section of the screen surface is 12-25 degrees; the rear section of the multi-layer screen is arranged by the probability screening method, that is, the large sieve hole at the discharge port uses a large inclination angle, and the small sieve hole Use a small inclination.

Compared with the prior art, the present invention has significant advantages: (1) the vibrating screen with multi-layer screen surface is designed, the screen hole is an inverted conical structure, and a conical protrusion is arranged at the feeding end of each screen hole, so that When the vibrating screen is classifying stones, the material will not block the screen holes; (2) Due to the use of the curved sieve plate structure, the screened materials will not pile up together and have the function of discrete stones, thereby improving the screening Efficiency, screening efficiency is about 30-50% higher than that of ordinary vibrating screens. At the same time, the discrete action reduces the wear of the stone on the sieve plate, improves the service life of the sieve plate, and reduces the number of screen replacements by 50% compared with ordinary screening devices; (3) Due to the use of a curved sieve plate structure, the The structural force is more reasonable, and it has the function of structural vibration absorption during vibration, which reduces the vibration transmitted to the frame by the vibrating screen, improves the service life of the screening device, and improves the dynamic characteristics of the tower of the asphalt mixing equipment; ( 4) The operating frequency of the excitation motor is 0.9-1.1 times of the natural frequency of the multi-layer screen, which has the function of preventing the blockage of the screen holes.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a schematic structural view of a discrete stone grading device of the present invention.

Fig. 2 is a schematic diagram of the multi-layer screen arrangement structure of the discrete stone grading device of the present invention.

Fig. 3 is a schematic diagram of the sieve hole structure of the discrete stone classifying device of the present invention.

Detailed ways

With reference to Fig. 1, Fig. 2 and Fig. 3, the discrete stone grading device of the present invention is composed of five parts: a screen box frame 1, an excitation vibration motor 2, a multi-layer screen 3, an inlet 4 and an outlet 5. The multi-layer screen 3 is supported and fixed by the wall panels on both sides of the screen box frame 1, and is connected with bolts; the vibration motor 2 is placed on the screen box frame 1, and is connected with the screen box frame 1 with bolts; the feed port 4 is in the Above the screen box frame 1, the two ends of the feed port 4 and the wall panels on both sides of the screen box frame 1 are connected by welding; there can be 6 discharge ports 5, which are respectively arranged below the feed port of each layer of screen mesh, and the two The end and the wallboard on both sides of the screen box frame 1 are connected by welding. The screen mesh 3 is tensioned horizontally by special splints on both sides of the screen frame, and then the tension plate is fixed on the screen box frame 2 with bolts. The curved structure of the multi-layer screen 3 is provided by the fixed brackets on both sides of the screen. Above-mentioned vibrating motor 2 is vibration source, and this vibrating motor 2 drives sieve box frame 1 and multi-layer screen cloth 3 to do reciprocating vibration, and the sieve plate 6 of multi-layer screen cloth 3 is a curved structure, and the radius of curvature of this curved sieve plate 6 3000-1000mm. The sieve hole 7 on the sieve plate 6 is an inverted cone structure, and the cone angle of the inverted cone structure is 10-60 degrees. A conical protrusion 8 is arranged at the feeding end of the sieve hole 7 on the sieve plate 6 , that is, above the material movement direction of each sieve hole. The spacing between the sieve holes on the sieve plate 6 is 2 to 2.5 times the diameter of the sieve holes. Among them, the front section of the multi-layer screen 3 is arranged by the equal thickness screening method, that is, the screen surface at the inlet 4 is divided into two sections, the inclination angle of the first section of the screen surface is 30-40 degrees, and the inclination angle of the second section of the screen surface is 12 to 25 degrees; the rear section of the multi-layer screen 3 is arranged by the probability screening method, that is, the large screen holes at the discharge port 5 use a large inclination angle, and the small screen holes use a small inclination angle. The sieve holes of the multi-layer screen 3 can be set to 3×3, 6×6, 11×11, 19×19, 30×30, which means that the sieve holes are distributed in a square, and the hole spacing is 3, 6, 11 respectively. , 19, 30mm. The specific layout of the multi-layer screen 3 is as follows: the mesh size of the first layer from the feed port to the discharge port is 30×30, 19×19, 11×11; the second layer from the feed port to the discharge port The sieve size of the third layer is 19×19, 11×11, 11×11; the size of the sieve hole of the third layer is 6×6; the size of the sieve hole of the fourth layer from the inlet to the outlet is 11×11, 6×6 ; The sieve size of the fifth layer from the feed port to the discharge port is 6×6, 3×3; the sieve size of the sixth layer from the feed port to the discharge port is 3×3, 3×3.

The stone enters from the feed port 4 on the screen box frame 1, and first reaches the equal-thickness screening section screen of the first layer of screen surface. After secondary screening, it enters the probability screening section screen. After the material is screened, The oversize material enters the silo through the discharge port 5, and the underscreen material passes through the screening of several layers of screens below, and enters the respective silo through the discharge port 5, so that the stones are divided into six different grades. As shown in Figure 3, the sieve hole 7 adopts an inverted conical structure, and a conical protrusion is added above the material movement direction of the sieve hole 7. In this way, it is convenient for the material to slide down when screening the material, and the probability of sieve hole blockage is greatly reduced. , can play the purpose of preventing sieve holes 7 from clogging structurally. At the same time, the frequency of the excitation motor 2 should be equivalent to the natural frequency of the sieve plate 6, specifically 0.9-1.1 times the natural frequency of the multi-layer screen 3, so that when the material particles with the same size as the sieve hole block the sieve hole, a A new system consisting of material particles, sieves, and support plates, because the excitation frequency of the vibration motor is basically equal to the natural frequency of the system vibration (consisting of the sieve, the material particles that block the sieve holes, and the support plate), when the sieve is blocked Resonance will occur, destroying the formation of screen blocking. In order to have a better resonance effect when the sieve hole is blocked, it is assumed that the natural frequency ω=(k/m) ^1/2 when the sieve is not blocked; the mass of the material particles blocking the sieve hole is Δm, and the Natural frequency ω′=[k/(m+Δm)] ^1/2 . The natural frequency value of the system should be concentrated as much as possible in the case of partial blockage and complete blockage, so as to enhance the anti-blocking effect. Therefore, if the above two points are to be satisfied at the same time, it is necessary to make Δm>m. For this reason, the following measures are taken: use lighter materials as the screen and screen frame to reduce m, and increase the area of the sieve to increase Δm. Therefore, in the present invention, the screen uses carbon fiber composite material, which greatly reduces its quality. At the same time, the curved multi-layer screen structure is used to make the screen area 1.2-1.5 times the screening projected area.

When the screening area, vibration performance parameters and material particle size composition of the vibrating screen have been determined, the selection of the mesh structure of the vibrating screen has a great influence on the processing capacity and screening efficiency of the vibrating screen. According to the sieving experiment, for multi-stage classification of multi-layer screens, the distance between adjacent screen holes is generally close to a certain proportional relationship, and the distance between the screen holes in the present invention is 2-2.5 times the diameter of the screen holes.

The present invention comprehensively considers the characteristics of the equal thickness screening method and the probability screening method, and adopts the arrangement of the equal thickness screening method at the feeding port 4 . This arrangement can increase the acceleration of the material layer, rapidly thin the material layer, and quickly stratify, increasing the speed of the aggregate inlet, thereby improving the processing capacity of the entire sieve machine; The layout of the sieving method allows the material to pass through the sieve quickly after entering the sieve. At the same time, it overcomes the shortcomings of the common sieving method that is easy to block the sieve holes, eliminates the influence of critical particles, reduces the wear of the sieve surface, and improves the efficiency per unit area. Processing capacity: Due to the multi-layer screen surface, several grades of products can be separated at the same time, so that the screening efficiency of the device is 30-50% higher than that of ordinary vibrating screens.

Claims (1)

1, a kind of discrete carpolite grading plant, comprise and drive the vibrating motor [2] that screen box frame [1] and multilayer screen cloth [3] are made double vibrations, this vibrating motor [2] is a vibration source, the sieve plate [6] of multilayer screen cloth [3] is a curved configuration, sieve aperture [7] on this sieve plate [6] is the inverted cone structure, it is characterized in that: the leading portion of multilayer screen cloth [3] is the layout of isopachous sieving, and promptly the compass screen surface located of feeding mouth [4] divides two sections, first section screen angle is 30～40 degree, and second section screen angle is 12～25 degree; The back segment of multilayer screen cloth [3] is the layout of probability screen point-score, i.e. the big sieve aperture high inclination-angle located of discharging opening [5], little sieve aperture small inclination.

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