Development status of vertical impact crushers at home and abroad

1. Introduction

Smashing is an indispensable means of obtaining valuable materials and various mineral raw materials in human daily life. The capital and production costs required for comminution are considerable. In particular, power consumption and equipment wear are the main indicators. Experts point out that the annual electricity consumption in the world is 3% of total electricity. Requiring fine crushing size, mechanical trouble-free operation, and minimal wear and energy saving of equipment are the subjects of crushing workers all over the world. The vertical shaft impact crusher is an efficient and reliable crushing and crushing equipment that has gradually emerged this year.

1.1 Introduction of vertical shaft impact crusher

Vertical shaft impact crusher (sand making machine) is widely used in medium and fine crushing of high hardness and special hard materials such as ore, cement, refractory materials, bauxite clinker, corundum, glass raw materials. It is widely used in the construction of sand, stone and various metallurgical slags. Especially for medium-hard and extra-hard materials, it has superiority to other types of crushers and has high yield efficiency. At present, it has replaced traditional equipment such as hammer crusher, roller crusher and rod mill, and has become the mainstream equipment in the sand making industry.

Figure 1.1-1 Dual motor driven vertical shaft impact crusher

Figure 1.1-2 Cutaway view of single-motor driven vertical shaft impact crusher

1.1.1 Working principle

The vertical shaft impact crusher is composed of a feeding hopper, a hanger, a vortex breaking chamber, an impeller body, a main shaft, a base, a transmission device and a motor portion. The working principle is as follows: the material enters the impeller cavity from the feeding hopper (via the center feeding pipe at the hanger), and the material is evenly thrown in the impeller flow channel by the feeding cone, and the impeller is accelerated instantaneously by the high-speed rotating impeller. From 60 to 75 m / s, it is ejected from the flow channel cavity around the impeller, impinging on the vortex lining in the vortex chamber, rebounding by the material lining, obliquely impacting the top of the vortex chamber, and changing its direction of motion. The deflection moves downward and forms a continuous curtain of material with the material thrown in the impeller flow channel cavity. In this way, a piece of material is subjected to two or more crushing impacts in the vortex breaking chamber, and the crushed material is discharged from the lower discharge port, and a closed circuit is formed through the circulating screening system, and the material is generally broken down to 4.75 mm or less after three cycles. The advantage of this type of crusher is that the crushing ratio is independent of the wear of the wear liner. Due to this property, any material, regardless of its wear resistance, can be economically crushed using a rotor centrifugal crusher to obtain a high-quality product having a cubic particle content of more than 80%. At the same time, the proportion of the broken surface is also increased. The ingenious airflow inside the vortex chamber self-circulates, eliminating dust pollution. The overflow feed does not need to increase the power consumption and wear cost of the crusher. The overflow feed increases the particle density inside the crusher chamber, more effectively breaks up more particles and improves energy utilization.

Figure 1.1.1 Crusher Breaking Schematic

1.1.2 structural composition

Vertical shaft impact crusher mainly consists of seven parts: feeding hopper, hanger, vortex breaking chamber, impeller body, spindle assembly, base, transmission and motor. The specific structure is shown in Figure 1.1.2 (section view of vertical shaft impact crusher)

Figure 1.1.2-1 Sectional view of the vertical shaft impact crusher

1.1.3 Application areas

(1) Quarrying

The vertical shaft impact crusher is recognized as a high-quality aggregate production equipment for paving asphalt , concrete, standard sand and the like. Can break a variety of materials, especially hard, abrasive rock. The high-speed impact crushing of the crusher can produce high-grade products at the lowest cost, while reducing noise and improving the shape of the stone, reducing the water content of the product and facilitating subsequent screening operations.

(2) Industrial ore
Vertical shaft impact crusher can effectively control product grading, high output, low operating cost, and can produce a large number of fine-grain grade products. Therefore, vertical shaft impact crusher is especially suitable for the processing of industrial ore. In the field of industrial ore processing, the highly abrasive industrial ore processing industry is particularly popular. Now, in the diamond mine, it becomes a high-efficiency equipment for extracting diamonds from industrial gangue; in the cement industry, it is also the preferred fine crushing equipment for cost saving, increased production, and production of mill feedstock.

(3) Mine
With the ability to crush and grind in one piece of equipment, it can process almost all hard, highly abrasive, brittle materials and viscous materials. The vertical shaft impact crusher has a high output and can produce fine-grained products. It can be used in the fields of grinding mill feeding, sintering feeding, quasi-dip and so on, and is an ideal alternative to high-cost, low-efficiency grinding equipment.

(4) Waste recycling
Due to the increasing awareness of environmental protection and the continuous development of the waste recycling industry, vertical shaft impact crushers are becoming an important part of the waste recycling field. Waste recycling is not limited to the recovery of construction waste, but also includes glass, slag and other renewables. Waste of economic value. It is an ideal method for processing such waste, and a variety of configurations can be applied to a variety of different fields.

2 . Research status at home and abroad

2.1 Development of domestic vertical shaft impact crusher

In recent years, domestic VSI machines have also developed greatly, mainly in the following aspects:
(1) There are more and more domestic manufacturers of VSI machines, and the new products of various companies are launched, and the production quantity of their products is also growing steadily;
(2) The specifications of the machine are gradually increasing. For example, the impeller diameter of Zhengzhou Yifan Company has reached 1 300 mm, the processing capacity has increased correspondingly, and the percentage of finished sand in the discharge has reached the advanced level, close to 50%;
(3)Comparatively standardized products, the comprehensive quality is stable, and the manufacturers start to control the vibration, noise, dust, etc. of the machine, and the service life of the wearing parts is improved. Some manufacturers report that the outer knives of the river pebbles are treated. The service life has exceeded 200 h;
(4) increased variety of machine, only small stones and stone at rock-iron, and the open impeller began to use individual companies, the guide plate reaches its life in normal use. Due to the above factors, domestic customers began to trust domestic VSI machines. In some applications, such as medium-hard materials processing, advanced domestic equipment can compete with imported equipment;

At present, the VSI machines in the domestic market can be divided into three types from the technical level: self-developed products (including imitation), Chinese-foreign cooperative products and all imported products. When the production scale of sand and gravel yards is getting larger and larger, the price of imported equipment is relatively high, and it has become the resistance of customers to purchase. The resistance comes from the difficulty of using high-grade wood and foreign equipment. Chinese-foreign cooperative products entered the domestic market late. Due to the mature technology and the localization of wearing parts, the Chinese partners can select and control the customers, provide better after-sales service, and make up for the shortcomings of the all-in-one equipment. Market competitiveness. Although domestically developed products come from imitation, if only based on price advantage, small in technology and quality, with the times, although the current sales volume is dominant, the prospects are not optimistic.

2.2 Development of foreign vertical shaft impact crushers

An important market enabler of vertical shaft impact crushers (VSIs ) is the provision of cube-shaped gravel to meet the specifications of super-laying materials. After being widely recognized by aggregate operators, current VSI users and manufacturers are pushing VSI applications around more satisfactory shapes or more profitable gravel.

Large-scale VSI machine with flexible mechanical properties, good wear-resistant materials and parts training, and more effective dust control system, is pushing the VSI machine in the fourth, second or even second level (broken) In the same way, the application is close to the level of horizontal impact crusher and cone crusher .

Improving the wear rate is the primary goal of every VSI machine manufacturer. Through the comprehensive training of the feed pipe, the distribution plate, the rotor and the guide plate, the throughput of the material passing through the crusher is increased, and this is achieved by casting the composite ceramic and tungsten on the high wear surface. In addition, manufacturers have been working to make alternatives to wearable parts that are more readily available and more robust.

The following is an overview of the differences between multiple manufacturers claiming that they are different in training and operation from other VSI machines.

(1) Cemeo
The top of Cemeo 's seven VSI models is the Turho160, Turho175 . Weighing 77,000 pounds (35t) of Turho175 is a "guide plate and the back plate" machines, stone Alternatively groove, which guide plates 3 a station can hold the guide plates 5, each weight 136 lbs (62kg) of The guide plate is said to require only two bolts to be fixed, and the other needs to be fixed to resist centrifugal force and crushing force. The best crushing effect can be obtained by changing the speed and impact distance. The company said that two Turbo 175 machines are powered by 800 to 1000 horsepower, and their throughput is between 800 and 1300 t/h , which has been in operation for more than one year. The Turbo 160 has similar processing power, but weighs just 56,000 pounds, just to meet the mobile. Both machines allow a maximum feed side length of 7" (about 180 mm ) when handling limestone , and Cemco is testing ceramic guide plates on a Turbo 175 machine.

(2) Impact Service Corp
ISC 's latest VSI machine is the Model 130 , weighs 86,976 pounds (excluding the motor), has a large drum of " 130 " (about 3,300 mm ) diameter and a " 61.25" diameter turntable with 266 pounds of guide plates, ISC It also introduces the Type 103, Type 70 and Type 82 VSI machines for the large turntable. The Model 103 turntable has a diameter of 54.5 with 4 bolted plate fastening systems and a vertical locking pin on the back of the guide plate. ISC believes this new training will allow for larger feed sizes and faster turntable speeds. Types 70 and 82 have a " 48.5 " diameter turntable and can hold up to 7 guide plates to get the finest product. According to ISC , the larger diameter turntable increases the guide plate space and can reduce the drag per ton of product. Dynamic current can increase throughput and reduce wood. In order to increase the life of wear parts, the company is developing a series of turntable guide plates, counterattack plates, and feed plates with inlaid ceramics.

(3) Kolbeng-Pioneer
The company's five model VSI machines handle the most human feed specifications from " 2" to " 6". Two of the models (machines) can be either a standard type (guide plate and counter-attack plate) semi-integrated (closed rotor and counter-attack plate) or a fully integrated (closed rotor and mixed rock groove) structure. The company's unique hybrid stone trough combines the “rock stone” and “stone iron” crushing methods. In the impact area in front of the counterattack, material is collected onto the stone trough to provide protection against abrasion. The company believes that the counter-plate supports the accumulated material from the back to increase the crushing effect. The company's VSI machine can use a guide plate turntable or a closed rotor. All wear parts of the closed rotor are bolted, including replaceable carbide strips (outer cutter). The turntable uses a pinned or nut-fixed guide plate and a replaceable liner.

(4) Metso Minerals
The company offers two series of products, the Barmac VSI crusher for the application needs of "stone stone" or "closed rotor and counterattack" construction. Barmac's B-Series products feature a closed rotor and stone trough, as well as a waterfall feed system that transfers part of the feed directly into the crushing chamber and bypasses the rotor. In the operation of the crusher, the waterfall material can be adjusted by a manual or automatic card system. Other adjustments to the crusher include rotor speed and diameter, and the hollow ring of the crushing chamber is selected. The operating control system displays vibration and bearing, motor temperature. The maximum feeding specifications for the seven models of the B series range from 3/4" to 3 ". The four models of Metso VI series VIS machines allow the maximum feed specification from 1.0 " (closed rotor) to 6 " (open rotor) in the same tear L frame, from open rotor and counter plate to NJ rotor And stone trough. The Metso VI series' unique cylindrical counter-attack plate converts when the half is worn. Metso said that the reduction in air flow and recirculation within the hood of the crusher enabled the VI Series to reduce dust emissions.

(5) REMCO
The company's rock soil and sand-making VSI machine series "stone stone" and ST / AR "stone counterattack board" VSI machine licensed feed capacity up to 1500t / h , feed specification up to 4". As the second level or Typical equipment of the fourth-class same road, the power required by the machine is from 60 hp to 1500 hp. The company's rotor can be exported by 3 , 4 , 5 or 6 plug-in training, small bolt-mounted tungsten steel The piece is easy to replace. The company claims that the replacement of the top and bottom wear plates with rigid AR steel reduces the amount of work required to weld the rotor. Four or five guide plate turntables are also available in ST/AR type.

The ST/AR type (with the same top cover/counter plate ring) crusher has a reversible counter-attack plate that is placed on the counter-plate ring at multiple positions that can be raised or lowered to increase the allowable wear of the counter-attack plate. All ST/AR models can be converted from a counter-plate ring to a stone-rock chamber. The company recommends counter-attacks to be used only when the material contains less than 15% abrasive components. 15% refers to the total percentage of silicon, l and iron in petrochemical analysis

2.3 Domestic and international product gap

Compared with the product performance provided by major VSI manufacturers at home and abroad, the gap between domestically produced machines and major foreign companies is comprehensive, mainly in the following aspects.

Customer service
Customer service, especially on pre-sales selection services. Most of the products currently developed by domestic manufacturers are based on imitations, often "knowing them but not knowing why." For different customer situations, due to the lack of experimental data, it often changes with small changes. Causes the same machine, different customers use different results. Defects in the customer's crushing and screening system can also affect the use of the VSI machine. For example, when the iron separator is not configured in the system, the entry of the iron will damage the machine. When the system feed size exceeds the allowable value, it will cause abnormal operation. When the feed contains too much moisture, the wearing parts will exacerbate the wear. When the feed cannot be adjusted, its small uniformity will affect the sand making effect of the machine and so on. These customers must pay attention to the situation, domestic manufacturers often can not be as detailed as their foreign counterparts in the customer selection, which also damages the reputation of domestic VSI machines.

2. Product specifications and performance
In terms of product specifications and performance, especially in terms of the size of the machine. The difference in the size of the large-scale foreign VSI machine compared with the largest domestic manufacturing specifications is a comprehensive reflection of the training level, the manufacturer's ability and the performance of domestic components (such as bearings). For example: The upper and lower faces of the rotor body are fastened with a conical ring. It can't be loosened at high speeds. The concentricity tolerance of the upper and lower cones at a nominal size of 600 mm is designed to be 0.02 mm by Kobe Steel. This design requires a test of the manufacturer's processing capabilities.

3. The service life of the machine
The service life of the impact crusher is originally lower than other types of crushers, such as squatting and conical. The vertical shaft impact type is even worse than the horizontal impact type. Therefore, the service life of the machine components is the lifeline of the VSI machine manufacturer, and the life of the parts is compared under similar operating conditions (see Table 2.3.1 ).

Parts life comparison table