Polivinil Rotomachinery


Company Articles

Development News from Rotomachinery Group!

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Over the past few years we have experienced a quite difficult market, one where the general market is very slow and we haven’t yet seen the expected growth in the European market or other areas of the world where manufacturers are technologically advanced and sensitive to innovation. However, even in more advanced markets, we are seeing new competitors who are offering low-technology and low-quality equipment utilizing a ‘reduced price’ as their principal marketing instrument.

At Rotomachinery Group, even in this difficult situation, we continually invest in research and development because, especially in the industry’s more advanced markets, there is a need to reduce production costs and achieve increased product quality. We have made that possibility a reality with Rotomachinery Group’s innovative and high-technology rotomoulding machinery and advanced resources.

Through Rotomachinery Group’s investment in research and development, good results have been achieved in all areas of intervention. These innovations have been highly appreciated by all our valued customers. For example: reducing manpower costs means reducing the number of working hours for each machine, however this requires increased attention to the construction of the machine in order to ensure the resources necessary for producing professional, high-quality products.

Rotomachinery Group is not only providing rotomoulding machines. We provide to our clients with personal solutions to make production more efficient in terms of working with the moulds; drawing of the production site; solutions to move and use raw materials; and ensuring the production of high-quality finished rotomoulded products.

image004 copyWe have just developed new software resident in our server that considers the weight of the parts and easy comprehension of mould positioning on the spiders of straight arms and on the flange of offset arms to keep the weight balanced. Using a PC in the office, the head of production can move the moulds with a click of the mouse and the program will show in real time any unbalanced point and propose the positioning and placement of the weight. All of this takes place without interfering with production. This technology includes high advantages in terms of mechanical stresses and life of the components. The client can check the production using a PC, Tablet, or Smart Phone and see on the screen the same pages of the Touch Panel on the machine. It is possible for one person to control multiple machines without being present.

Rotomachinery Group’s machines are a referral point in the market regarding consumption savings. Through the quality of the insulation and the shape of the cooking chamber, considering the speed and the pressure of the airflow of the hot air on the moulds, it allows for the same cycle time, a reduction in consumption of 20%. Such significant reductions of cycle times are achieved with the same consumption rates.

Moving a further step ahead, Rotomachinery Group has now developed the UFD System Upper Fan Duct, which directs some of the hot air onto the moulds. This is an extra hot air pipe that uses the same heat source without increasing consumption. We have introduced the new hot air blowing fans composed of two turbines that reach the optimal rotation in rapid time and also in fast time they reduce the speed, reducing the loss of hot air during the opening and closing of the oven doors. This provides maximum advantage in combination with the ECOMODE System where the burner stops when the doors of the oven are opened and the exhaust works at the minimum power.

Another innovation developed by Rotomachinery Group, REGEN, utilizes energy lost from the machine and uses it again for the machine or for other external needs. With REGEN, moulders are able to re-use the energy lost from the inverters every time the motors reduce the speed and make reverse rotations.

At Rotomachinery Group we are currently studying special heat exchangers, air-air and/or air-water, to enable moving hot air coming from the exhaust to use it to heat the factory. Our highly-technological software will control all these functions and even control the internal temperature of the moulds during the heating and cooling phase. It will direct the exit of the arm from the oven when the part is perfectly processed and it will stop the cooling cycle when the part reaches the desired temperature.

These innovations are important in the event of material changes, changes in product weights, testing of new moulds, or for the initial start up of production each morning because cycle changes are affected by different conditions. The reduction of the cycle times depends on a better cooling phase. We have reached this goal by using new types of cooling fans, which are more powerful (28.000 up to 55.000 m3/h each), less noisy, and less electrical consumption. The savings acheaved are real and our clients can look at this in real time on the Touch Screen of the machine. The electrical and gas consumption can be set for each working cycle, cubic meters, weight of the products, and with a certain time frame.

The technologically advanced machines and personal solutions produced by Rotomachinery Group ensure value over time and ensure value for investment because our satisfied clients are still using our machines produced in the 80’s. For further information please contact Rotomachinery at www.rotomachinerygroup.com.

Rotational Moulding

A growing technology for the production of manholes

A company profile

The replacement of concrete manholes and septic tanks with plastic manholes (mainly polyethylene) manufactured by rotational moulding is advantageous for many reasons: simplicity and safety of production; technological superiority; affordability; environmentally friendly; ease of handling; and installation on site. Moreover, the integration with pipes and ducts is simpler, faster and fully integrated; as these are made today mostly in plastic.

Rotomachinery Group offers complete rotational moulding lines specifically designed for the production of manholes, septic tanks and other types of rooms for the treatment of wastewater and drinking water. Rotational moulding technology produces manufactured articles free of structural tensions, easily weldable with the tubes to ensure the seal and prevents the escape of liquid pollutants. Another advantage is the excellent levels of internal surface roughness, which facilitate the liquid flow avoiding the accumulation of dirt.

Mechanical propriety of the material and the characteristics of the parts guarantee excellent impact resistance, impermeability of chemicals and an excellent barrier to the aggression of plant roots and trees. In case of replacement or displacement, moreover, the manholes can be easily and economically recycled.

Modular Systems

The most popular diameters of manholes are 40, 50, and 60 cm. For inspection chambers the diameters are 80, 100 and 125 cm. The latter can be as high as 50 cm. to 6 m., depending on the number of rings elevation. A manhole, in fact, is a modular system that includes a base and lid, which are interposed rings of elevation to reach the road level on the top and connect to the sewage system at the bottom. The base can be equipped with various inlets/outlets with different diameters according to the pipes and fittings. The rings of elevation have a seat for the gasket at the interior of the joint and steps to facilitate inspections. The lid is placed at zero and may include steps or reinforcements for the toughest jobs, while in the case of special situations (trafficability) can be made of concrete.

The various components of this modular system are all produced in rotomolding already equipped with coupling seats for the gaskets, and the inner step reinforcements. The components normally weigh 18 to 35 pounds, making it easy to stack, transport and safe for manual installation without the use of special means. In the pipeline, therefore, the operations are limited to the welding of the pipes with the manhole and the installation of seals. Installation times are significantly reduced since there is no need of cranes for the laying and leveling the sewer system.

The use of plastic manholes also avoids the most expensive manual intervention typical of systems in which the preparation of cement concrete is necessary: breaking of the wall of the rooms; the hose connections; sealing by hand of the fittings; and rings, etc.

Machine Process

img-02Plastic manholes are made with special moulds, a 3 or 4 arm rotomoulding machine equipped with an oven, a cooling system and two or more working stations for loading of the raw material and unloading of the finished products.

A machine of adequate size can mould simultaneously several modular components: bases with 1, 3, or 5 couplings, rings elevation of various heights, and different types of lids of different diameters.

The machine can also be equipped for other useful products in the pipeline such as road barriers or tanks. The same part can be achieved with different thicknesses (normally from 3 to 20 mm.) by varying the amount of material processed. The high flexibility enables easy replacement of moulds, even with the machine running and provides an economical production for small runs also creating significant cost savings.

Market Evolution

90% of pipes and fittings for water treatment today are produced in PVC, PP and PE by injection moulding or extrusion moulding which, thanks to their convenience, have allowed the rapid replacement of traditional artifacts.

This change has not affected the manholes because these technologies are not suitable. Switching to a plastic manhole has not yet reached this percentage.

In Europe, in fact, 90% of the manholes are still of the traditional type. In Germany, for example, over 1000 manufacturers manufacture concrete manholes, while twenty manufacturers are producing manholes in plastic by rotational moulding.

However, the situation is changing in favor of plastic. First of all, there is a growing awareness for environmental protection. A fully sealed system, which eliminates sewage spills, offers greater guarantees of land conservation and recovery of the water. The increased safety in operations is another factor in favor of plastic systems. Unfortunately, injuries to workers are common in construction sites.

img-03The final push, however, is due to the drafting of technical standards (EN 13598) on the subject, which is the result of many years of work. The market is growing and earns most of the current share occupied by manholes and inspection chambers made with traditional materials. And rotational moulding is the right technology for this product and has to be considered the most advantageous too.

First of all for consideration is the cost. The plant for rotomoulding requires, compared to other types of machines, a considerably lower investment. Its flexibility allows the production of tens of parts and large lots, with an ease of changing moulds and thicknesses, which is not equally possible with other technologies.

Next, rotational moulding is the choice for high capacity tanks (thousands of liters), rooms for electrical wiring and telecommunications, pumping stations, clearing houses and measurement, drainage basins, storage tanks, etc.

Rotomachinery Group can boast years of experience in this area for the development of rotomoulded plastic manholes and
for the essential knowledge for the design of molds.


Company Profile


The efficiency in energy consumption of rotomoulding is generally poor. R&D departments at Rotomachinery Group have come up with substantial innovations as a result of the active collaboration between Italian and North-America engineers with customers, using our machines on 5 continents. Before introduction into the market, the improvements were tested in the new Research Center including an area of 2,000 square meters, which was recently opened at the Italian facility.

REGEN-Regeneration of Energy

It is a special bi-directional power supply serving all the machine motors controlled by inverters. Inverters convert DC to AC and return the energy generated from the motor during the phase of deceleration or stop when the motor acts as generator.

On a rotational moulding machine it quite often happens that the electric motors decelerate or reverse the rotations such as:
– deceleration of the oven doors
– deceleration of the carts in positioning
– deceleration/reverse of primary/secondary rotation
– deceleration of the oven and cooling fans

REGEN takes this regenerative energy production and uses it for the other motors. When this “recycled” energy exceeds the machine needs, the surplus goes into the general circuit to feed other utilities (light of the building, for example). You can see on a digital counter the amount of energy consumption and the amount of regeneration

ECOMODE – Reducing Energy Consumption

Ecomode is a working modality of the oven where the basic principle is that the burner stops when the oven is empty or the temperature falls below a set. The maximum results are reached when the machine is equipped with a full digitally controlled burner, new-designed cooking fans, well–insulated oven panel, and automatic management of the cycle.

At the end of the cooking cycle, ECOMODE stops the fans when the doors open. The new-designed cooking fans (turbines), managed by inverters, need only 5 seconds to stop rather than 1 minute as as is usual with one big fan. This reduces the hot air pushed out of the oven with a minimal loss of temperature and creates a big regenerative energy at the same time!

There’s a real-time display of all the combustion to be compared data with the optimum consumption in order to find the more efficient mix. The turning off of the burner and its restarting increases the time needed to restore the set of the temperature but with the good insulation of Rotomachinery Group machines and using the reliable automatic machine management, the savings in energy consumption is higher than the disadvantages of the increased cooking time.

The process steps are determined by the temperature presented by the thermocouples placed inside the moulds. Big savings are achieved in case of unbalanced cycle time when the oven is empty for long time; the first cycle in the morning could run without pre-heating and for the last cycle the burner turns off automatically. The exhaust fan ejects the hot air with the combustion fumes: this unceasing loss of energy has been substantially reduced with an active management. With ECOMODE, when the burner is off, the exhaust fan works at a minimum.

In addition, a new special device designed to recirculate the hot air in the oven has been installed. It takes a part of the hot air returning in the combustion chamber and conveys this heat on the mould again, but in another position creating a new heating point where is possible to optimize the entire cooking which allows achievement of additional moulding advantages. The operator enables the ECOMODE function, simply tapping the icon on the touchscreen of the panel. The customer who for any reason won’t accept the increased cooking time can turn off ECOMODE tapping on the screen, but keep all the advantages of the regenerative unit.

New Cooling Fans
A new type of fans has been installed with reduction of noise level and electricity needs. Efficiency is higher as well. With the same energy absorption, we’ve increased the cooling power for a medium size machine from 28.000 to 40.000 cubic meter / hours.

Machines in a Digital World
All the data of the process are available in real-time, not only on the touchscreen of the machine but on a PC, tablet, and smartphone as well. Users can see the status of the process live and in real time including the gas consumption every 10 seconds. Aware of the importance of the data and to avoid damages or misuses, the access to the system is protected with a password-level system. Operators have access to limited area and only the supervisor can change critical settings. The problem with the password loss or revelation is solved with the fingerprint authentication, where by only the supervisor can change the main parameters.

Market Outlook: A Growing Technology for the Production of Manholes

Rotomachinery Group presents itself as a valid and experienced partner for turnkey projects for the production of manholes. The replacement of concrete manholes and septic tanks with rotomoulded products is in progress in many countries because of the simplicity of the production process, the technological superiority of the products, and the ease of handling installation. Moreover, the integration with pipes and ducts is easier, as nowadays they are made mostly in plastic.

Compared to concrete construction, plastic articles are free of structural tensions and easily weldable with pipes, ensuring the sealing and prevention of liquid leakage. Inside the parts we have smooth surfaces with the advantage better liquid flow and avoidance of dirt accumulations.

The mechanical properties of PE manholes provides the guarantee of an excellent impact resistance, impermeability from chemicals, and protection from the aggression of the roots, whereas in case of replacement or displacement, the manholes can be easily and economically recycled.

Potential growth in this business sector is tremendous just considering that 90% of pipe and fittings are manufactured in plastic and only 10% of manholes and other water treatment tanks are manufactured in plastic.

Environmental awareness, easiness of handling, and the superiority of parts are already changing the scenario, and rotomoulding is the right technology — first of all because of the costs. The investment for a complete rotomoulding line for the production of manholes is lower in comparison to the other plastic technologies that in most of the cases do not even guarantee the quality of the product. The main advantage of rotational moulding technology is flexibility. With the same machine it is possible to produce a full line of manholes with several elements of different thicknesses, from small to big output, and at the same time make other parts like road barriers, septic tanks, water tanks, rooms for electrical wiring, and telecommunications, pumping stations, drainage basins, etc.

A Modular System for Rotomoulding

The most popular manhole diameters are 40cm, 50cm, and 60cm for the inspection chambers; and 80cm, 100cm, and 125 cm for manholes. They can be as high as 50cm to 6mt, depending on the number of elevation rings used to connect the ground level with the piping system underground. A manhole, in fact, is a modular system where every component has a place for the gaskets and steps to make the inspection easier. The base can be done with various inlets, parts, and outlets, designed to match the specifications of the connecting pipes and fittings.

The components of a PE manhole, weighing from 18Kg up to 50Kg, make it easy to move, transport, and install. It is not necessary to use special cranes. On site, the operations are much faster because there’s only to weld the pipes and to assemble the seals, no need to prepare the concrete walls of the rooms, the hose connections, the sealing hands of the fittings, the rings, etc.

Rotomachinery Group suggest its 4000mm size machine with 3 or 4 independent arms because of the different cycle times of the parts. Manholes are technical parts and hi-technology machines are needed to control the process and to have the required quality to follow the standards. The products are made with different thicknesses, normally from 3 to 20 mm, simply changing the amount of material processed.

Rotomachinery Group Profile

Polivinil Rotomachinery is fully focused on rotational moulding and it is considered one of the major and most reliable manufacturers having around 1,000 machines working all over the world with over than 40 years of experience in the specific field of rotomoulding. At the company’s two facilities in Italy and Canada, we design, produce, assemble, test, and install our rotational molding machines and accessories for the rotational moulding industry. A state-of-the art machine is available in both our factories for materials and mould testing, and they are used to develop products and the process innovations.