Explosion protected forklifts and lithium ion batteries from Stöcklin


The science and technology company Merck KGaA uses explosion protected floor handling equipment with explosion protection batteries and standard floor handling equipment with lithium ion batteries from Stöcklin for first time.

Merck is a leading company in the science and technology field specializing in the areas of health care, life science and performance materials. A staff of nearly 50,000 is working on further development of technologies to enrich life - from bio-pharmaceutical therapies to treatment of cancer or multiple sclerosis using ground-breaking systems for scientific research and production right up to liquid crystals for smartphones and LCD televisions. In 2016 Merck obtained turnover figures of 15 billion Euros in 66 countries. 
Founded in 1668, Merck is the world’s oldest pharmaceutical-chemical company. The founding family has maintained majority holdings in this market-listed company right up to the present. Merck, with headquarters in Darmstadt (Germany), possesses the global rights to the name and brand ‘Merck’. The only exceptions are the USA and Canada, where the company is known as EMD Serono, MilliporeSigma and EMD Performance Materials. 

Special solutions for sensitive work areas

At the end of 2015 Stöcklin expanded the Merck KGaA’s forklift fleet at the headquarters in Darmstadt to include a series of state-of-the-art electric drawbar stackers. These vehicles meet the ATEX Guideline 2014/34/EU (ATEX = ATmosphères EXplosibles), which is analogous to European Directive 94/9/EC for placing explosion protected electrical and mechanical machines and components on the market. These machines are suitable for use in Zone1, where an explosive gas atmosphere can be present occasionally, as well as in Zone 21 for explosive dust atmospheres.
As a specialist for customer-specific solutions, the Swiss OEM manufacturer has adapted the electronically driven, explosion-protected equipment according to further developed specifications by Merck. New requirements included, for example, modified foot guards, a piece of stainless steel on the wheel arms to reduce sparking and a special circuit for bypassing the brake, allowing vehicles to be moved out of a hazard area, such as an explosion-endangered zone, for repair. Other requirements included an increase in the supporting capacity from 1,600 to 1,800 kilograms, a cargo protection grate, as well as moving the key switch and warning lights to the chassis.

Assessment of opportunities and risks

In view of the range of items offered, the logistic processes at Merck are distinguished by safety considerations at the highest level. Risks result, for example, when handling combustible gases, vapors and dusts. For the floor handling equipment in use this means prior submission of internationally valid certificates and prototype test certificates verifying that safe operation is possible without further conversion even in explosion hazard areas.
The same now applies for use of lithium ion batteries for standard vehicles. Decisive factors for this alternative to conventional lead acid batteries include, among other items, a significantly high power density and longer service life, increasing the availability of the vehicles. However, skepticism continues, nourished by reports of batteries catching fire, for example, in smartphones. “Lithium ion batteries continue to be the subject of controversy. Nevertheless we decided in favor of testing this technology in a Stöcklin forklift, because the staff at Stöcklin convinced us that the design and safety features used ensure safe operation of their lithium ion batteries. The advantage of lithium ion batteries for our application, is the elimination of central charging stations with vapor evacuation and monitoring. This allows the vehicles to be charged directly in the production facilities (while maintaining a sufficient safety interval). This is particularly advantageous for new buildings and in the GMP area”, said Bernd Hoerr (Vehicle Manager at Merck KGaA).
Simultaneously it was necessary to observe specific safety aspects defined by Merck. “Here the design, control and composition of the batteries was important for us. We were particularly impressed with the way Stöcklin designed the structure and control, because so many points were taken into consideration in advance, that it was possible to put the machine into service on a short term basis after hazard assessment by the specialized department, the operating company, labor safety authorities and the fire department”, continued Mr. Hoerr.

Tested and documented safety

A delegation of representatives from the plant fire department, plant security, battery management, purchasing management and project management initially assessed use of lithium ion batteries in external, practical application. On site it was ascertained, that this technology is in wide-spread use, in the meantime, and no mentionable problems have been reported regarding use and handling of the batteries. “After further discussions and a hazard assessment by those responsible at Merck, supported actively by provision of all significant data by Stöcklin, we were pleased to order the first vehicle using lithium ion technology”, said Jörg Backhaus, ATEX Representative at Stöcklin Logistik AG headquarters in Dornach, Switzerland.
During the mechanical test by an independent, accredited special laboratory, the batteries, with integrated electronic safety circuit, were subjected to intensive testing. Each of these tests included three axis or position “sine-wave vibration” as well as “semi-sine-wave shock tests”. Visual and functional checks were performed following each individual test. A final report documents the results of the tests passed with the rating “approved”.
During the course of the hazard assessment for use of the lithium ion batteries in floor handling equipment, including the charging process, possible sources of danger, from which hazards or stress could arise, were initially identified. The criteria included organizational factors, workplace layout, ergonomic aspects, mechanical and electrical hazards, hazards from fire and explosion, such as overcharging or extreme discharge of the battery, effects of water/moisture, dusts, low temperature and many others. This provided the basis for defining protective measures, with the help of which it will be possible to avoid any negative effects on a preventative basis.

Final exam under actual conditions

The first side-seat stacker with lithium ion technology developed and supplied by Stöcklin has been in service at Merck in Darmstadt since the end of 2016. “We anticipate great expectations from this purchase” stressed Mr. Hoerr. “Long battery service life, capability of intermediate charging, short design of individual assemblies, elimination of central charging stations by charging batteries in production, thus ensuring more efficient processes and cost savings. The machine has been in service successfully for four months and the operators love it.”

The German Stöcklin dealers at NHK, Marcus Kissel as well as the ATEX Representative at the Swiss Manufacturer, Jörg Backhaus, are convinced that lithium ion batteries and the Stöcklin ATEX series will prevail in the long run.

Author: Urs Grütter