A gas cleaning system, which is operative for cleaning a process gas containing carbon dioxide and sulphur dioxide, comprises a combined cooling and cleaning system, and a CO2-absorber. Walls of the holes comprise a gripping resilient material. The apparatus and method further include a transparent element, the transparent element part of a set of replaceable transparent elements, each replaceable transparent element having a particular width, the width less than the width of the gap. The linear oscillatory motion of the tool holder is generated by a rocker which is arranged vertically to the tool holder, extends through the casing and is driven by the eccentric of a drive motor with an associated frequency converter. Version control may be used to ensure project team members are working with the latest designs and revisions.