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Les autoclaves Olmar ATV pour vulcanisation sont principalement utilisés dans l’industrie du caoutchouc, mais ils sont aussi présents dans les processus de consolidation des autres matériaux comme l’acier et le plastique.

L’utilisation de ces autoclaves est très rependue dans divers secteurs comme l’automobile (principalement lié à la vulcanisation des pneus), l’industrie navale (fabrication des défenses et des accessoires), la conception de rouleaux et tapis roulant ou la vulcanisation des éléments complémentaires (tubes, manches, joints, etc.). Cette grande variété des marchés fait que les autoclaves Olmar ATV pour vulcanisation soient un des équipements le plus demandé aussi bien au niveau national qu’international.

Tout le processus se déroule de manière totalement automatique grâce au nouveau logiciel Olmar OCS, développé intégralement par les ingénieurs d’Olmar et permettant de contrôler, étudier et agir sur toutes les variables du cycle en temps réel. Ce système moderne garantie un résultat final optimal, permettant en outre de développer les différents programmes de travail, de suivi et de contrôle adaptés aux différents besoins de chaque client.



The use of vulcanized rubber in the most technologically advanced industries has become widespread in recent years, going from an accidental discovery to unprecedented industrialization in the automotive sector at the beginning of the 20th century.

Let’s briefly review its history: During one night in 1839, Charles Goodyear left natural rubber mixed with sulfur on a hot plate; the next morning, said rubber had been converted into elastic rubber, having carried out the first rubber curing cycle in history. This process was patented by Mr. Goodyear in 1843 (but also by Mr. Thomas Cook in the United Kingdom, giving rise to different theories about its invention).

Since heat and sulfur had been associated with the god Vulcan, this process came to be called vulcanization.

Illustration 1The forge of Vulcano (D. Velázquez)

Autoclave vulcanization is a chemical process applied to rubber and other natural compounds with elastomeric properties, which increases their elasticity and decreases their plasticity, thus improving their mechanical, physical and performance properties such as hardness, viscosity and resistance (mainly to traction and weathering).

Olmar autoclaves for vulcanization (ATV) allow these processes to be accelerated, allowing natural rubber and plastic (synthetic rubber) to be safely and optimally converted into parts and cured products.

With application in countless sectors and industrial processes, the exponential growth of autoclaved rubber is mainly determined by its use in:

  • Coating and repair of tires for heavy vehicles, such as trucks and off-road vehicles (OTR – Off Road Tires).
  • Coating and repair of tires for passenger vehicles (SBR – styrene butadiene rubber)
  • Roller coatings on conveyor belts
  • The coating of rollers in printing
  • The manufacture of rubber gaskets for the automotive, aeronautical and shipping industries, radiator hoses, spark plug cables and caps (EPDM rubber).
  • Electrical applications such as insulation of high voltage cables
  • Coating of high temperature cables
  • Manufacture of low, medium and high pressure rubber hoses and sleeves
  • The manufacture of protective rubber covers in which thermal resistance to ozone, weather, corrosive chemical substances or oils are essential properties.
  • Curing of seals and gaskets (O-rings)
  • Others such as mats, boots, etc.

These products, improved thanks to the autoclave treatment process, will be used in abrasive conditions and/or in extremely corrosive environments, thus extending their life cycle and improving their performance. This result is generally not achievable by standard press-based compression molding.

The rubber vulcanization autoclaves manufactured by Olmar (called « ATV ») stand out not only for their high level of technological development, but also for their reliability and durability, which guarantee the best performance and the highest levels of efficiency throughout their useful life. The application of rubber in increasingly critical manufacturing elements has brought with it an exponential increase in the demand for control, fatigue and measurement tests of this equipment. Only the most advanced autoclaves are capable of guaranteeing the levels of homogeneity and cycles demanded by the industry, which is why investment in R&D and their constant improvement are increasingly important.

In this sense, since the beginning of its activity within this sector (the company represented Uniroyal in Spain for more than 15 years in the 1970s), Olmar has dedicated a large part of its R&D resources to the investigation of the possibilities of these new materials, being a reference company at national and international level in its study and industrial application.



As we have indicated, rubber is basically an elastomer that can be of natural or synthetic origin (made in petrochemical plants by chemical synthesis), and which is subsequently vulcanized in an autoclave to improve its physical and structural properties.

In a standard cycle, once introduced in the autoclave, the rubber must reach a temperature of 170ºC (350ºF) and a pressure of 6 BarG (90 psi), remaining at that temperature and pressure for a pre-established time. These conditions may vary depending on the type of rubber and its application.

It is essential to define correctly with the supplier the maximum time in which we want to reach those temperature and pressure conditions, thus optimizing the productivity that we expect from our autoclave. This data is essential when comparing and aligning different equipment and choosing the most suitable one for our process.

The variety of existing cycles for the vulcanization of rubber entails the existence of a large number of different types of autoclaves in relation to:

  • Dimensions: Olmar offers autoclaves with a useful Ø diameter from 500 mm. to 10,000mm. , and lengths of 1,000 mm. to 60,000mm.
  • Maximum working temperatures and pressures (up to 482ºF) and 21 BarG (300 psi)
  • Materials: carbon steel, stainless steel or a combination of dissimilar materials
  • Layout: horizontal or vertical


The most common phases to follow during a vulcanizing cycle are the following:


1 | Heating and pressurization

The heating and pressurizing means to be used inside the autoclave are conditioned by the nature of the rubber to be vulcanized and its purpose, with four main modes:

  • Direct steam: through the direct introduction of saturated steam into the autoclave chamber (Olmar is also a reference manufacturer of steam boilers, with more than 1,000 references in the world and >75 years of experience).
    • In these cycles, the pressurization can be correlated to the temperature of the steam, or carried out independently by introducing compressed air.
  • Indirect heating by introducing steam or thermal oil into an exchanger located inside the autoclave, recirculating the hot air inside by means of a turbine and its motor.
    • In this case, the pressurization is carried out independently by introducing compressed air into the autoclave.
    • The use of hot air instead of steam allows direct contact of the rubber with the steam to be avoided, minimizing moisture infiltration and thus achieving greater adherence of the vulcanized rubber.
  • Indirect heating by means of electrical resistances, recirculating the interior air of the autoclave by means of a turbine and its motor.
    • In this case, the pressurization is carried out independently by introducing compressed air into the autoclave.
    • The use of hot air instead of steam allows direct contact of the rubber with the steam to be avoided, minimizing moisture infiltration and thus achieving greater adherence of the vulcanized rubber.
  • Mixed heating with direct steam | Indirect: An autoclave developed by Olmar to be able to work with the best of both technologies at all times, according to needs.


2 | Stabilization phase

Once these target conditions (temperature and working pressure) have been reached, we must maintain them for the minimum time established during the stabilization phase, which is carried out fully automatically thanks to the OCS (Olmar Control System) control system equipped with Siemens PLC technology. or Allen Bradley.


3 | Cooling

As in the heating phase, the cooling and depressurization means to be used inside the autoclave are conditioned by the nature of the rubber to be vulcanized and its purpose, with three main modes:

  • Natural cooling: the autoclave cools naturally as the steam inside is extracted.
    • In some cases, it is necessary to compensate for this depressurization by introducing compressed air to guarantee an optimal finish of the product.
  • Cooling by shower or spray: the autoclave is cooled by water introduced from the top of the autoclave and sprayed on the product by shower or spray.
  • Indirect cooling: this system is based on the introduction of cold water in an exchanger located inside the autoclave, recirculating the air inside the equipment by means of a turbine and its motor.



1| By direct steam

Once the autoclave is loaded, pressurized saturated steam is introduced, subjecting the tires to the programmed temperature and pressure conditions.

2| By indirect heating

In this type of cycle, each tire is encased in an « envelope » (rubber cover) which in turn has a valve through which it is possible to introduce compressed air to press it.

Once the autoclave is loaded, the hoses are connected to the envelopes in order to provide them with pressure during the cycle.

As we have explained previously, in this case the hot air is obtained through the recirculation of steam or thermal oil in an exchanger, or also through electrical resistors. As the internal temperature rises to 125ºC (290ºF), the envelopes inside the tires are inflated and pressure is introduced into the autoclave (with a difference of 2.1 BarG (30psi), until the chamber reaches a pressure of 5, 5 BarG (80 psi) and tires at 8 BarG (115 psi).

At that moment, the envelope that covers the tire is pressurized up to 4.2 BarG (60psi); This pressure is generally called “third pressure” and it guarantees optimal bonding and a better tire finish.

This part of the process usually lasts approximately 120 to 150 minutes.

Once the previous stages have been completed, depressurization is carried out in the following order:

  • Third pressure
  • Tire pressure
  • Autoclave pressure



Precision and reliability are fundamental factors within the rubber manufacturing processes. Due to the high levels of demand in the automotive and construction sectors, it is necessary to carry out an exhaustive monitoring and control of all the processes that take place inside the autoclave. In this sense, Olmar has developed the most advanced software in the world for rubber vulcanization autoclaves, thus meeting its goals of digitization and efficiency in manufacturing processes. This is, in short, an intelligent autoclave, capable of automatically controlling heating in its different modes, pressurization with air or saturated steam, maintenance of vacuum, pressure and temperature values ​​during curing and subsequent cooling and depressurization, allowing control and parameterization of each of the manufacturing phases. All this allows us to achieve optimal vulcanized rubber, both in finishes and properties.

It is not only important to control and analyze these values ​​(pressure, vacuum or temperature) during the cycle, but also after it; Thanks to the study of all the data collected during the process carried out inside the autoclave, it is possible to detect possible points of improvement and optimize the cycle to the maximum. Through a control system developed entirely by the company through its electrical and software departments, Olmar offers its customers optimized performance, and through its innovative reporting technology, the most precise data control and analysis on the international market , making a firm commitment to the development of the so-called « Industry 4.0 » and applying all the innovations available in its autoclaves.

In short, Olmar has focused its efforts on creating an « intelligent » autoclave, focusing its developments in the fields of energy efficiency, usability, predictive control and low maintenance.

Its OCS (Olmar Control System) control software integrates all these functionalities, reducing the consumption costs of the autoclave, improving its productivity and optimizing any periodic maintenance task to be carried out. Thanks to its high connectivity and the incorporation of the most advanced remote connection solutions, our technical service offers first-class support in any country in the world.

All this encompassed in a solid business structure, family tradition and at the same time flexible and agile, capable of carrying out the entire manufacturing process « in house »; a company focused on the continuous search for innovation and growth. This is demonstrated by its new division of « Cold Additive Technology » (Cold Spray), a revolutionary concept born from our investment in R&D.



Olmar is today a world leader in the manufacture of autoclaves for rubber. This leadership is mainly based on the combination of traditional and innovative engineering and in-depth knowledge of both the autoclave and the process.

In this field, Olmar also has an important advantage over its competitors: its knowledge and production capacity in terms of steam generators, with more than 1,000 references and 50 years of history.

In this sense, we recommend you visit our section dedicated to « Steam Boilers », where you will find the different ranges of boilers that we manufacture, with productions ranging from 100 kg/h to 30,000 kg/h.

In addition, Olmar has the capacity to optionally offer its customers a « turnkey » solution that includes all the auxiliary systems that complement the autoclave / steam generator for rubber vulcanization:

  • Manual, semi-automatic or automatic loading systems.
  • Silencer for low noise emissions during depressurization
  • Hardware and sensors for process monitoring

The possibility of selecting a single supplier, both for the autoclave and for its auxiliary equipment, facilitates communications and the integration of all of them, as well as a greater probability of success in the final result of the project.



The company’s experience, endorsed by thousands of international references and top-tier clients, has been increasing over the years based on values ​​such as excellence, effort and constant innovation. Leading companies such as Michelin, Bridgestone, Continental, Siemens or Hutchinson, among many others, have relied on Olmar autoclaves to develop some of their most important projects, in products that offer the most advanced solutions for the automotive, electrical energy, etc. . Proof of this are the numerous processes in which Olmar autoclaves and control systems are used and integrated.

Olmar is present in all of them, actively participating in current and disruptive projects that will change our future, contributing effort, excellence and innovation in technological solutions for the manufacture of autoclaves for rubber vulcanization never seen before. Our OCS control software, currently considered the most advanced application for rubber treatment, places Olmar as an international reference company in an increasingly competitive world market.

The increase in the consumption and production of tires are undoubtedly upward trends, which define a market in which the individual turnover of large companies exceeds 20,000 million euros.

Olmar is today a trusted partner to face this challenge in any country in the world.



The presence of more than 1,500 Olmar autoclaves in 150 countries today constitutes a success story, and a heritage passed down from generation to generation (today Olmar is a fourth-generation family business).

All this is accompanied by the latest international certifications, both at the manufacturing level, as well as procedures and quality, having, among others, the CE (Europe), ASME (America and Asia), SELO (China), JIS (Japan), Etc.



In this promising scenario of growth and new challenges, Olmar establishes itself as a world reference company, presenting its equipment and technological solutions as a guarantee of maximum quality and efficiency to face the challenges of the industry in the coming years. Thanks to the experience acquired throughout its more than 75 years of history and a team of highly qualified expert technicians, the company faces these new challenges with the security and confidence necessary to respond to the needs of its customers around the world. .

Olmar, your partner for the future.

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According to current Personal Data Protection regulations, the responsible for processing your data is INDUSTRIAL OLMAR, SA. Your data will be processed for the purpose of sending you the bulletin issued by our entity or the news and services that may be of interest to you. You can consult more information in the Privacy Policy of our website.


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