Numerous industrial processes have an inherently risky potential. Special pressure switches support the safety of people and the surroundings. Example: the vulcanisation of tyres for automobiles. To monitor this process, leading manufacturers utilize the model MW switch from WIKA with SIL 2 rating.
Why this type of pressure switch is necessary for safety in this application is shown by way of a consider the process: In a steam-heated press, the raw tyre is first filled with hot water to adapt it to the inner form of the press. Then, consuming pressures of around 24 bar and temperatures of 150 �C to 170 �C the vulcanisation itself occurs. Along the way, by adding sulphur, the tyre is given its elastic and robust final shape. However, if there is no appropriate monitoring, overpressure may appear in the curing press unexpectedly. If this happens, the danger of boiling hot steam escaping is high. To rule out this occurrence, tyre manufacturers generally use pressure switches to guarantee the safety of the procedure.
The model MW pressure switch with SIL 2 rating has been developed for safety-relevant applications, such as for example tyre vulcanisation.
Control of overpressure and interlocking
The instruments fulfil two functions simultaneously: On the main one hand, they intervene in case of overpressure, and on the other hand, they control the internal interlocking of the curing press to avoid it from opening accidentally before vulcanisation is completed. The procedure is finished when a preset pressure value is reached. Then your pressure switch lifts the lock. This mechanism is continually in motion in high-throughput automatic tyre production. Because of this, the switch is continually being loaded. Consequently, it will need to have a long service life at this critical point. Premature wear would otherwise result in an unscheduled shutdown of the plant.
ร้านซ่อมเครื่องวัดความดันโลหิต require pressure switches with distinct robustness and safety. Because of this, WIKA has developed the model MW pressure switch for safety-relevant applications such as vulcanisation. As a mechanical device, the model MW will switch without reliance on any energy supply, an important safety aspect. A SIL 2 rating relative to the IEC 61508 standard certifies the functional safety of the pressure switch. Its operational safety is also SIL 2 certified. Thus, the expected service life is about 90,000 pressure cycles and switching operations. The risk assessment of the model MW in accordance with EN ISO 13849-1 by an external certification resulted in the highest performance level ?PL e? (lowest failure probability).
Microswitches, also with argon filling
All model MW instruments have microswitches that switch electrical loads up to 250V AC, 20 A directly. For several applications, microswitch versions with argon filling offer an additional boost to safety and service life. The gas reduces oxidation, protects against corrosion and prevents sparking. For low switching powers, for instance in PLC applications, there is a variant with gold-plated contacts.
Retrofitting existing plants
The model MW safety pressure switches from WIKA are also suitable for retrofitting. In the case of tyre vulcanisation, they are able to therefore help to adapt existing installations to the specifications of DIN EN 16474, which was amended in 2015. This standard obliges tyre manufacturers to operate new machines with improved safety technology. The regulation is intended to prevent risks of danger in the long run.
Note
More info on the model MW pressure switches and their safety features can be found on the WIKA website. For those who have any questions, your contact will gladly help you.
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