The hydrogen expert Graebener® expands its product portfolio and supplies one of the most renowned electrolysis companies with its latest innovation, the stack press, that is used in the manufacturing process of alkaline electrolyzers.
The Graebener® stack press supports the technical testing of electrolysis stacks at the end of their production process: The pre-assembled stack, which consists of a large number of plates, is first moved into the machine and then compressed to a defined height until a certain pressure is reached within the stack.
The stack press for electrolyzers has a force of 800 tons and can handle stacks with a maximum height of approx. 3.0 m, a maximum diameter of 1.60 m and a weight of up to 12 tons per stack.
This pressure must then be maintained unchanged for several hours. At this time, the stack is subjected to all the necessary technical tests carried out by the customer and with the help of further procedures. These are necessary to confirm its full operability. As soon as the tests are completed, the stack is finally assembled with tie rods or tension straps and the finished stack is removed.
In order to be able to guarantee assembly work during operation with maximum safety, a hydraulic drive was deliberately avoided. Instead, the stack is compressed inside the press by means of six servomotor-driven spindle units. These are operated synchronously and thus enable particularly homogeneous compression of the stack. The maximum pressing force per spindle unit is 150 tons.
The biggest challenge was to compensate for production-related stacking tolerances. Stacking tolerances are unavoidable, but when the stack is compressed, they cause transverse forces which can damage the stack. In order to eliminate these and to build up an even pressure distribution within the stack, these transverse forces must be continuously compensated for during compression of the stack. This is done with short-stroke cylinders that are located under the six spindle lifting elements and enable an even distribution of pressure.
Photo of Graebener
Press release https://is.gd/TtUIfY
