Crushing Systems (Continued)
Crushing Systems (Continued)
Crushing Systems (Continued)
(continued)
Power Consumption and Wear Costs
A frequently-quoted advantage of vertical shaft impactors is their lower power consumption, a point easily challenged if the actual amount of product generated is taken into considera-tion and not the throughput alone. For instance, if one assumes a specific power consump-tion of 2 kWh/ton based on the throughput of a vertical-shaft impactor, this figure soon in-creases to more than 5 kWh/ton if the much lower percentage of the actual final product thereby generated is taken into account; as a rule, this consumption figure is higher than that of the AP-VM impact crusher based on the actual percentage of product generated. Yet pre-cisely the latter figure is relevant, since the plant operator can only earn his money with mar-ketable products, but still has to pay for the power consumed in the generation of those products.
Another often-quoted advantage of vertical-shaft impactors, that the wear costs are lower; can also be refuted on the basis of the same reasoning.
Function and Flexibility
Let us now turn our attention to the flexibility of the various crushing systems and their influ-ence on the quality of the mechanical sand produced. As varied as are the uses of sand in the building industry, so contrasting are the quality requirements.
Mechanical sand is produced by the further crushing of unwanted oversize. Of course, such oversize becomes available in varying quantities, however, the quality requirements with respect to the intended use remain constant. Irrespective of the type of material which is processed to produce mechanical sand, a consistently-high product quality is of paramount importance. Such requirements place high demands on the flexibility of the crusher. A uni-form product must be guaranteed for the whole life of the wear parts irrespective of the dif-ferences in the type and size of the feed material
The very versatile horizontal-shaft AP-VM impact crusher has a vertical inlet (Fig. 1), which ensures that even the smallest lumps of feed material achieve the necessary penetration depth to reach the crushing implements, i.e. the blow bars. The four-bar rotor in combination with the use of a frequency transformer allows the crushing process to be aligned to the feed size and the characteristics of the material being processed.
Fig. 1: Cross-sectional view of the HAZEMAG AP-VM impact crusher
Attachments
■
Crushing Systems (Continued)
(continued)
The AP-VM impact crusher can handle feed material of up to 150 mm in size. The machine’s flexibility is enhanced by the quick and easy push-button adjustment of the hydraulically-actuated impact apron and grinding path settings. Moreover, compensation for crushing im-plement wear can be effected not only by implementing running adjustments to those set-tings, but also by varying the tip speed of the rotor. The crusher’s symmetrical design per-mits reversal of the rotor’s direction of rotation. During the course of the crushing operation, material wear results in the sharp edges of the active blow bars becoming rounded, which obviously affects the granulometry of the final product. As soon as the radius becomes ? than half the width of the blow bar, the rotational direction of the rotor is reversed, and a new sharp blow bar edge is introduced into the operation.
Accordingly, there are 5 easily-set parameters, i.e. rotor speed, rotational direction, and three variable settings to guarantee a product of consistently high quality. Vertical-shaft im-pactors, on the other hand, usually offer only speed adjustment as a variable parameter. The highly-successful HAZtronic automatic control system is also available with the AP-VM im-pact crusher, allowing its integration into external plant measuring & control systems with visual monitoring. Using the HAZtronic system, from the main control desk, not only can the operational status of the machine and the plant be observed and controlled, but also the gap settings, rotor tip speed and rotational direction of the rotor adjusted during operation to suit immediate requirements. All data can simply be stored in the computer as recipes and called up as required.
Maintenance
From a servicing point of view, the HAZEMAG AP-VM impact crusher also sets new stan-dards in ease of maintenance. There are large access doors on both sides of the crusher housing, which is lined with handy-sized, easily-replaceable wear plates. The slide-in grind-ing beams can be turned for double wear. The blow bars are similarly inserted from the side to enable them to be turned/changed quickly with little effort. The end result is a minimum of down time in response to maintenance & servicing requirements.
Summary
Summarising, it can be said that the HAZEMAG AP-VM series horizontal-shaft impactor is superior to so-called vertical-shaft impactors with regard to power consumption and wear rates. This fact is principally supported by the significantly better crushing results achieved, and the lower percentage of fines generated in a single pass. Furthermore, special mention must also be made of the crusher’s inherent flexibility which allows for the generation of dif-ferent products whilst at the same time maintaining a consistently high quality level. Ease of operation and a high degree of automation coupled with low maintenance requirements pro-vides for trouble-free operation with minimum down time.
For more information, please visit:
href="https://edir.bulk-online.com/profile/8845-hazemag-group.htm" target="blank">https://edir.bulk-online.com/profile...emag-group.htm
Fig. 2 An AP-VM impact crusher with the housing open
Attachments
■
Crushing Systems
A Comparison between the HAZEMAG AP-VM Impact Crusher and similar crushing systems with regard to the production of high-quality mechanical sand
Benefiting from flexibility and efficiency
by Stefan Koch
HAZEMAG & EPR GmbH
Since the AP-VM impact crusher was introduced by HAZEMAG to the public some 2 years ago, it has proved its flexibility and efficiency in many varied operations and processes. In a several cases, the AP-VM horizontal-shaft impact crusher has been installed not only to re-place existing vertical-shaft impactors, but also ball mills and other vertical-shaft crushers mounted downstream thereof. The result has been an impressive improvement in quality and capacity, and at the same time a considerable reduction in production costs.
How can these exceptional results be explained?
Granulation curve
First of all, let us compare a typical granulation curve of products from conventional vertical-shaft impactors with that of a HAZEMAG AP-VM impact crusher based on various feed sizes (Tables 1 – 3). A striking feature of the HAZEMAG AP-VM curve is that it is much steeper than that of a vertical-shaft impactor. The consequence is that the AP-VM impact crusher has two essential advantages over a vertical-shaft impactor:
1. A much higher percentage of product <4 mm is generated in a single pass
2. At the same time, the percentage of filler is considerably lower.
In other words: The HAZEMAG APVM horizontal-shaft impact crusher can generate a con-siderably higher percentage of the actual product granulation in a single pass than can a vertical-shaft impactor. Thus, in many cases, not only are savings made in the expensive and time-consuming removal of excessive amounts of filler material, but also in reducing the high and ineffective circulating material load which is unavoidable when a vertical-shaft crusher is used.
Table 1
Attachments
hazemag_1 (JPG)
■