At the tank-making factory of heating technology specialist Vaillant in Bergheim, Pilz’s consultancy services have culminated in what Pilz calls “An exceptional safety solution”. To keep an individual positioner’s loading and unloading area free from obstructive superstructures, the transmitters of Pilz PSENopt II light curtains have been embedded horizontally in the floor, with the receivers mounted on a steel structure above the machine. As a result, two of Vaillant’s older production lines can now be kept in safe operation for the coming years, and operated in full compliance with the required safety standards.
One of the classic challenges in safe machine and plant design is that access to certain areas should be as free as possible due to operational and task requirements. At the same time, safety requires people to maintain minimum distances from dangerous movements: smart safety concepts solve this dilemma so that productivity isn’t restricted. This is what was put into practice at Vaillant’s Bergheim site where the heating, ventilation and air-conditioning technology specialist manufactures storage tanks for hot water, (amongst other things).
A total of 54 tank production plants have been retrofitted with the latest electrical and safety engineering solutions. Process sequences determined the safety solutions required, and according to Jörg Holzportz, Head of Industrial Engineering at Vaillant: “Pilz is the only company that presented an integrated and complete range and convinced us of how essential systematic risk analysis is”. An analysis of potential risk and optimisation conducted internally by Vaillant formed the basis of the risk assessment and the resulting safety concept. Trialling at an initial pilot plant confirmed the chosen approach, but in two tank-enamelling production lines, problems with the associated individual positioners remained.
The individual positioners fix tanks and are accessible from three sides. Electric drives rotate the tanks, which hang above a basin along two rotation axes so that the cast enamel reaches every corner of the tank’s interior in equal measures. Pilz’s hazard analysis revealed crushing, shearing and impact risks, so the installation method was redefined accordingly. Up until that point, the individual positioners had been protected with pressure-sensitive mats, the solution embraced due to modified standard requirements. However, an alternative safety solution based on light curtains were chosen instead. This, says the company is because “In both the production and logistics operations, light curtains are always the first choice when the process requires man/machine interaction”.
Pilz’s PSENopt II Type 3 light curtains can be used for applications up to PL-d in accordance with EN/IEC 61496-1. With finger protection resolution and 14mm spacing between beams, the horizontally installed light curtains transmit their beams vertically to the receiver units mounted on the ceiling. This installation method allows a minimum distance from the danger source of either 96cm or 56cm to be implemented.
In the control cabinet, the PNOZmulti 2 configurable small controller processes all the safety-related signals, and the PSENopt II Type 3 light curtains are connected directly to the PNOZ m B0 base unit. If a machine operator interrupts the light beams emitted from the floor with their body, hand or even just a finger, or if they step on the pressure-sensitive safety mats laid out at the front, the small controller initiates the process of bringing the hazardous movement to an immediate and safe stop. There is a door in the individual positioner’s rear area that can be opened for maintenance purposes and here, a Pilz PSENmlock safety gate system combines safe interlocking and safe guard locking to the highest category, PL-e.
At Vaillant, the plants that have been modernised with regard to safety run without any interference at all and are therefore more productive and cost-efficient. Jörg Holzportz concludes: “The cooperation with Pilz was open and fair in each phase. We received a competent consultancy service at all times. The trick is even thinking up this kind of installation method in the first place!”
Unsurprisingly, further projects are already being planned and implemented in the partnership between Pilz and Vaillant. Learn more at www.pilz.co.uk.