Equipment

Raskat OJSC showcased its novelties at the ÑÒÒ’2008 international exhibition. The company is planning to update its lineup of produced rolling machinery and launch a new range of 1.5 to 21 t operating weight road rollers of a wide range of various applications by late 2009.   One of the peculiarities of the new lineup is   a maximum   range of each group of rollers.   The whole lineup is powered by a state-of-the-art  Kubota (Japan)  diesel engine    with a low noise, vibration and emissions level,     Bondioli & Pavesy (Italy) pumping facility,   Sofima hydraulic filters,   Poclain Hydraulics and Trasmital Bonfiglioli (Italy) planetary gear units.

The Raskat RV-1,5-DD (1) asphalt roller is designed to compact asphalt covering foundation in areas where high maneuverability and mobility is necessary.  In comparison with its   predecessors the    RV-1,5-DD rollers boast higher performance, maneuverability, they are environment-friendly and highly reliable in operation   due to foreign components. The model’s operating weight is 1.5 t and it is fitted with two  580 mm diameter driving drums. The roller build with an articulated frame  provides high maneuverability and enables it to operate efficiently in confined areas at walls and  borders and move on a curved trajectory with up to 3 m  radius of curvature.   The RV-1,5-DD compressed  lane width is 850 mm. Its operating speed can amount to 10 km/h, the reversing possibility and high vibration frequency – 60 Hz – ensure its excellent efficiency. The roller is good for maintainability and diagnosis which together with its components’ high quality brings to a minimum an incidence of unsheduled repairs. It is based on the module principle implying up to 90% unification of its parts and components  in the roller lineup.

The Ràskàò RV-2,0-DD and RV-2,4-DD are hydraulically driven on both drums thus reducing the compressed ground shift and boosts its ability to grade climbing. Rollers are fitted with one or two vibromechanisms that accelerate the centrifugal  driving force 20 and 25 kN respectively.  The vibrator oscillation frequency equals  55 Hz. Great attention is paid to the machine ecological compatibility as a pavement roller operates most of the time in residential areas.         2- and  2.4-t rollers compact 1 and 1.2 m lanes respectively at a pass.     To ensure the compacting factor  from 0.97 tî 1 they need from 2 tî 8 passes. And the asphalt concrete layer thickness      makes up  3 tî 5 cm.  A  2 t model’s efficiency lies within    330 tî 530 m2/h, while a   2.4 t model has capacity of 400 tî 640 m2/h. The new series of Raskat rollers  has a boosted fuel and water tank capacity.   The RV-2,0-DD and RV-2,4-DD are equipped with tanks of 30 L for diesel fuel and 100 L for water.   It ensures the rollers’ longer operation time   and their high performance correspondingly.   Oil in the  hydraulic system   has a very high grade.   First, the hydrosystem power fluid  is discharged from the circuit and filtered after shop tests. It helps   remove various  impurities from the oil which form at   new mechanisms breaking-in. Second, the circuit uses   an effective filtration system to considerably increase the engine and hydraulic drives’ life. The rolls and hydraulic drive elements’ power unit life  before overhaul is 10 thousand hours. The articulated frame provides high maneuverability and keeps drums’ traces overlap. The hydraulic booster facilitates the front half-frame’s turning. Compact engine dimensions allowed installing a bevel fiberglass hood on both drums which positively influenced visibility. In most cases pavement rollers are fitted with a safeguard bow. To boost the operator comfort the three models were fitted with an easily mountable canopy to protect against precipitation and direct sun lights. The operator seat is disposed on shock absorbers to improve labor conditions.

Dynapac offers a great variety of this class models in Russia.  Its lineup of compact pavement rollers comprises eleven models (2). The series of compact  double drum vibratory asphalt rollers is represented by the 1.6 t ÑÑ800/900/1000 models with 800, 900, 1,000 mm wide drums respectively.    The rollers   are powered by a  Perkins high-capacity low noise 3-cylinder water-cooled diesel engine. In the standard version both rolls are fitted with drive and vibration hydraulic motors, a new type of a sprinkler system under the triple filtration system pressure     and a self-discharge function     to minimize freezing in cold weather conditions. They also have a modern dashboard with discernible  symbols,  display and fuel  indicators. A capacious 110 L water tank and a sprinkler system timer are installed in the models.   The operator’s seat is spacious and vibroinsulated. The CC900G (3) with 1.3 t weight and 900 m drums (vibratory drive on the frontdrum) is powered by a gasoline engine with 18 hp capacity.  The constructive features of the      ÑÑ900S are drums with 60 mm outreach to the right. It enables the operator to compact asphalt    in immediate proximity to obstructions such as kerb-stones, hammer-stones, walls, pillars, fences and the like. This roller weighs 1.6 t and has  900 mm wide drums.  

The Dynapac model range is also represented by heavier pavement vibratory rollers: the ÑÑ102/ÑÑ122/ÑÑ142 with 2.3, 2.6 and 4 t operating weight and  1,070, 1,200 and 1,300 mm wide drums.  The machinery is equipped with Deutz low noise  engines with     23, 23 and 34 kW capacity respectively.   Like tandem rollers, the ÑÑ102Ñ/ÑÑ122Ñ/ÑÑ142Ñ combi rollers  with 2.3, 2.6 and 4 t operating weight   and 1,070, 1,200 and 1,300 mm wide drums are powered by Deutz low noise engines with  23, 23 and 34 kW capacity  respectively.

  XCMG rollers have gained a wide distribution in Russia over a short period.  All rollers of this company are manufactured on Dynapac technology.  The XD series machines have two drums, are fitted with a hydraulic transmission and electric- hydraulic   control system that regulates vibration frequency and  amplitude, a “crab pace” mechanism   and   atomizer.    These models differ from the previous models in an improved and more ergonomically-built cab design, boosted   capacity characteristics  – they are powered by more efficient engines, the total weight is increased (due to heavier drums), control systems are added and a more efficient electronic system is implemented. 

The  Sakai Japanese company launched  road rollers in    1929. The new generation of   the  SW502 (4), SW352, TW502, TW352 tandem rollers with    1.32 to 4 t weight and combi rollers from 1.23 to 3.54 t operating mass are powered by new engines  compliant with  TIER III standards. All tandem rollers have a run drive for two drums.   Each drum is also vibratory.     Hydraulic motors of the run and vibratory shaft drive are disposed on a cross circuit to ensure optimum weight distribution.     Over drums there are injectors to spray liquid. Combi rollers   have a supplementary tank for    Nepparan special liquid that disperses onto pneumatic tyres to prevent asphalt mix adhesion to them.   The new engines have lower emissions and fuel consumption.   Increased vibration frequency   allows carrying out compression at high speeds thus     boosting the machinery performance.   Considering low quality of Russian diesel fuel, rollers have an extra fuel filter.   Vibratory rollers of this series are easy to handle and comfortable thanks to a  hydrostatic drive and front/rear running shifting lever on both sides of the dashboard. Two speeds help choose   an optimal operating mode.  Two amplitudes of the vibratory unit   can be chosen according to operational conditions.  Absence of outstanding elements in the roller construction facilitates compaction jobs near borders and buildings’ walls.   

The German division of JCB is in charge of roller and other compaction equipment production.   It was established on the basis of  Vibromax, a company acquired some years ago.    The lineup of small (pavement) tandem rollers with a sitting operator place has been expanded by: the VMT 160 (5) in five different modifications,  and a heavier VMT 260 (6) in two modifications. In comparison with the previous models they have a more advanced appearance, the operator seat and safety controls have been seriously upgraded.   The rollers have an articulated frame   providing   a low turning radius with the mechanical turn regulation, it can be mechanically adjusted relative to drums’ lateral displacement  within +/– 65 mm for the VMT 160 and  +/– 80 mm for the VMT 260. This option facilitates ground compaction close to borders and other obstructions. To operate in the nearest proximity to walls, gates and other high objects the VMT 160 is presented in the modification with a one-side roll attachment (TSC index). To ensure  smooth and convenient speed control and  high  traction performance all machines have a hydrostatic drive    with electronic control of both drums.  High quality and speed are reached by   vibration switched on both or only the front or only the rear drum. Automated vibration control system facilitates the operator performance and makes it safer and more comfortable. A fully adjustable seat with armrests is installed in the machines,    they also have an automatic back-up audio alarm.   Compared to the predecessors the new    JCB Vibromax rollers have an easier access to   the engine and other important units to reduce   time  expenses for routine inspection, maintenance and repairs.  Besides,  the capacity of roll wetting system fuel and water tanks has been considerably increased which greatly boosted the new machines’ performance.      

The new model lineup of Caterpillar CB14 (7), CB14 XW, CB22, CB24, CB32 (8), CC24 in contrast to the previous  E-series rollers is powered by new ecologically safe engines that comply with Stage IIIa European ecological  standards.  The C1.1 engines are installed in the CB14 and CB14 XW models, ànd the C1.5 engine in other models.   The hood design has been altered to improve visibility on the sides and in front of the roller      and to enhance access to the engine during maintenance.    The improved engine and vibratory system construction led to increased intervals of oil    change in the engine up to  500 motor hours   vibratory system maintenance up to    3,000 hours. The new equipment   has a beltless  hydraulic  drive  of drums. Both drums are driving. At stops double frequency vibration is automatically switched off.

Volvo has showcased its new models of high efficiency small rollers. The DD-16, DD-24 (9), DD-38HF (10) models have a fuel tank with a capacity to provide the whole operating day and a large water tank. Comfort and safety is provided by vibratory drums with vibratory isolators and four operator platform post insulators   to reduce vibration transfer. The operator seat is accessible from both sides. The machinery is fitted with a parking brake which has a spring brake and hydraulic          shutdown. The    TwinLoñk traction control system and the torque transfer system   decrease the drum spin-out which result in   optimum roller control at all speeds and in both directions.  

 

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Alas, not all companies (including well-known) responded to the participation in the article. It aroused some perplexity with our editorial staff.  What is more, a Russian representative of Ammann company  –   Martimex – suspected some dirty trick and even malicious intent in the review on rollers. The crisis seems to be not only in Russian economy but in the people’s minds as well.   

Unfortunately …

 

 

 EXPERT OPINION

 

G.V.Kustaryev, academician of the Russian engineering academy, head of the Road-building machines department, MoscowAutomobile and Road Institute of State Technical University

 

Various producers of new compact rollers on offer focus on efficiency boosted due to structural alterations of the fuel and lubricating systems, installed filters and supplementary fuel and power fluid clean-up systems in the hydraulics.   A module kitting-up of rollers is  being developed which streamlines equipment diagnostics and reduces repair work time. The environment protection   against emissions makes companies compete in the sphere of up-to-date engine development compliant with all international ecological standards.   The operator working place is constantly changed as producers take into consideration all wishes of companies that operate the equipment. New rollers are more manoeuvrable compared to an old line-up. Updated control systems and all other changes make producers more competitive in the national and international   markets but in chase of modifications compaction equipment producers are distracted from the compaction process technology itself    which is the rollers’ ultimate aim.  The machinery still lacks interaction between  the ground to be compressed and the machine compressing it.     And the feedback in any sphere is known to be a  key to popularity and success. It will help not only boost the equipment efficiency but   track the compacted ground parameters and their change to regulate the impact of movable operating elements – drums, their basic parameters such as weight, power force, vibration frequency and amplitude. The existing systems are based only on response vibration change considering impact loads on a compacted layer. What has happened in the medium remains a mystery up to now.  There is no analysis of compaction quality control and   temperature changes in the compacted asphalt concrete mix, the question of vibration influence on surrounding buildings and constructions is still poorly studied. As for positive tendencies in the home roller market, they are a wide range of new machines by Russian producers whose goods are much less expensive that those of their foreign counterparts. It is a good sign showing that road building is developing. We want to wish compaction equipment producers  to avoid the existing clichés and focus on the compaction quality which  in its turn will lead to other positive results. They will   have a beneficial effect on the environment and the operator comfort. It will also reflect on low operating costs and  preserve moral strength.