Development concept of PrJSC Kredmash: report at the AutodorExpo 2019 exhibition

18.11.20192535 Page views

The Kremenchug plant of road machines has been producing asphalt mixing plants since 1949 and was a monopolist in this industry at the time. Today, in the market of road equipment, one can meet many competitors who also produce asphalt concrete plants.

In order to keep up with the times, PrJSC Kredmash has released a fundamentally new range of asphalt concrete plants and also offers an effective modernization of “old” ones.

Read about the current concept of plant development in the report by Sergey Perepelchenko, the deputy chief designer of PrJSC Kredmash. The report was first presented at the conference as part of the AvtodorExpo thematic exhibition in Kiev. Today, the Kremenchug plant of road machines wants to share this information with all its other partners and customers.

Modern asphalt mixing plants and road construction trends

As we mentioned earlier, there were many competitors of the enterprise at the exhibition, which encourages us to work even more efficiently at improving the quality indicators of our asphalt concrete plants. However, there were also enough potential buyers of equipment. And that  is a good thing for our country, for our roads, for our economy.

Before talking about Kredmash products, I want to touch on the trends that are observed in the construction of roads. So in Europe, asphalt recycling in the form of adding asphalt crumbs to the recipe and more than 60% of the weight of the batch is becoming increasingly relevant. And this is clearly seen in the design of the proposed plant models from leading manufacturers.

We also see additional units for feeding “old” asphalt up to individual drying drums with an autonomous system for dispensing crumbs and feeding them to a mixer. Some companies took up the course towards a line for processing the used asphalt as the basis of an asphalt mixing plant, when the preparation of a new asphalt mix in a classic way is an additional option only.

The need to build new roads and to conduct thorough repairs of existing ones in Ukraine so far brings the production of asphalt concrete mix according to classical technology, starting from the base of the road and ending with the top layer with the surface treatment, to the forefront. 

New asphalt mixing plants by Kredmash are designed in a way that allows to produce high-quality asphalt mix for both the lower and the upper layers of the road surface, taking into account the peculiarities of using domestic concrete aggregates and bitumen.

Of course, every road worker knows that bitumen and dust are probably the two main components that affect the quality of the asphalt mix and the durability of the road surface.

The quality of bitumen used in Ukraine, as a rule, requires the use of various kinds of modifying additives. 

Plus, one should not forget about the increased dust content of stone materials and the type of crushed stone used in Ukraine (which is granite), which also affects the ability of bitumen to adhere to crushed stone.

Kredmash: a new model range of asphalt mixing plants and their advantages

So what can Kredmash offer the buyer? First of all, a new model range of asphalt mixing plants with a capacity of 60, 80, 110, 160, 200 tons / hour. The design of a 240 tons / hour plant is in the future. All these plants are characterized by the following parameters:

1. Sieving and, accordingly, dosing of stone materials is carried out in 5 or 6 fractions, depending on the installation model, using a screen with external vibrators, in which bearings of increased carrying capacity and a safety margin of over 10 thousand hours are installed. The area of wire screen is up to 45 m2, which ensures high-quality sieving, including one for the top layer of the roadway; 

2. There is a good supply (up to 50 tons) of heated stone materials in a thermally insulated “hot” hopper, the compartments of which are equipped with continuous level sensors and temperature sensors. It is also possible to take samples from any compartment of the “hot” hopper. All this allows the operator to ensure continuous operation of the installation without unnecessary stops and starts.
3. Once again, I would like to focus on the increased dustiness of the source stone materials used in Ukraine. As you know, very fine dust, especially granite one, negatively affects the quality of asphalt concrete and the ability of bitumen to envelop grains of crushed stone. That is why the Kredmash asphalt mixing plants have a separate, complete dust aggregate, which includes a storage silo with a capacity of up to 55 m3 with the possibility of sifting dust to the side, a separate dust elevator and a measuring dust hopper with a capacity of up to 900 l, which acts as an accumulator, and a system for transporting dust to a weighing batcher or back to a storage silo, which is especially important when there is a lot of dust in the source material.
   
   In addition, it is possible to feed a large fraction of the captured dust into a “hot” elevator. Thus, the operator has enough capabilities to control the amount of dust in the recipe, or completely exclude it from the recipe, which is necessary for some types of asphalt mix (for example, gussasphalt).
4. Further, the mixers have a drive power reserve, which allows the operator not to be afraid of cold starts, starts of a loaded mixer, engine overload during bitumen discharge, etc. The blades and protection of the mixer racks are made according to modern technology and “live” 70 ... 100 thousand tons of granite. Increased attention is paid to the armor protection of loading and unloading trays, especially for elevators, drying drums, mixer bodies. Measures have also been taken to combat the segregation of the finished mixture in storage hoppers.
5. It is impossible not to mention bitumen. By far, bitumen, as the most expensive component of the mixture and as the main binder in the recipe, requires a lot of attention and costs from the road builders. Kredmash offers aggregates of adhesive additives for supplying additives to the mixer both as a separate delivery and ones integrated into the construction of an asphalt mixing plant. Bitumen mixing tanks are available for the preparation of modified bitumen based on powdered polymers also in the form of a separate supply or installations integrated into the bitumen equipment of a plant.
   This year, Kredmash has set up the production of vertical bitumen tanks in a 50 m3 auto size.
6. A modern dust-cleaning system based on bag filters and modern burner equipment for drying drums and oil heat generators provide environmental standards for emissions of harmful substances into the environment.
7. Naturally, modern European requirements for the safety of staff and the environment are implemented in new installations. Namely, a system of security locks that automatically turn off equipment when opening quick-access hatches, doors, as well as convenient and safe access to various mechanisms for maintenance and repair.
8. Comfortable working conditions for an operator with a climate control system, a good overview of the installation, an intuitive interface of a computer control system – all this is the standard for a modern asphalt mixing plant and all this is implemented in products manufactured by Kredmash.
9. In general, if experienced road workers analyze the technical characteristics of asphalt mixing plants of the new Kredmash model range, they will see that the main components and assemblies have a margin in their parameters and, thus, the standard equipment freely provides the declared technical passport capacity.

Modernization of “old” asphalt plants

I would like to say a few words about the modernization of old Kredmash production facilities. Over the current year, the plant’s specialists developed and implemented the following modernization lines for the construction of plants:

1. new vibrating screen with wire screens of increased area and external vibrators for the DS-158, DS-185;

2. a mixer with an approximately 30% increased area of the blades on the shafts and a more powerful drive;
3. an economical and environmentally friendly burner from our partner Information Systems Company for a drying drum with increased heat capacity, providing a specific fuel consumption of about 6 ... 7 kg per ton of the finished mixture;
4. a separate supply of a dust aggregate for plants of the DS-185 type, which includes a storage hopper, an elevator, augers and its own dust batcher;
5. a separate supply of a unit for sorting stone materials into 5 fractions, including a screen with external vibrators and wire screens, a “hot” hopper with 5 full compartments and a new dispenser for stone materials.

All of these options allow you to upgrade the customer’s asphalt mixing plant type DS-158, DS-185, KDM201, DS-168 and actually increase its productivity and reach a modern level of quality of the asphalt concrete mixture.

A promising direction is soil mixing plants, which in the current conditions of the development of road construction in Ukraine are gaining new life due to the fact that they allow not only to produce mixtures for the foundation of roads, but also to provide cold recycling technology after modernization. Today, Kredmash produces continuous soil mixing plants with a capacity of 240 t/h, equipped with a microprocessor control system that controls the dosage of cement, water and bitumen emulsion, i.e. necessary components for cold recycling, with high accuracy. In addition, the capabilities of MCS and the optional equipment of the installation allows the production of lean concrete.

If the customer needs to use the “old” asphalt on a conventional asphalt mixing plant, then in the new model range of Kredmash production plants there is an opportunity to install a line for dosing and feeding the “old” asphalt to the mixer (up to 20% of the batch).

It is a storage hopper for asphalt crumb with an inclined conveyor and a vertical elevator. At the top there is a feed hopper with a weight dispenser on load gauges, as well as a bulk tray equipped with an airlock. Thus, asphalt granulate weighing up to 20% of the weight of the batch gets into the mixer. Humidity of asphalt granulate is quite high. And the moisture, as you know, during evaporation increases in volume by about 1200 times. Therefore, an additional gas duct from the mixer to the smoke exhauster (through a bag filter) is required to remove the steam generated in the mixer.

The product range of Kredmash also includes concrete mixing plants, equipment for patching, mini-sprayers, equipment for public utilities: incl. snow ploughs, sand and salt spreaders of various modifications, etc.

Deputy chief designer

S.V. Perepelchenko