Abstract: An elongated element, for example, a soot blower for the cleaning of wall surfaces, is guided along a predetermined, meandrical blow figure. The element is supported in two spaced-apart cardanic joints (3, 4) the first of which is stationary and the second axially moveable on a first spindle (6) the ends of which are axially moveable on two parallel second spindles (8). The first and one of the second spindles (6, 8) are each provided with two non-mechanical, inductive proximity switches or end switches (11-14) which are connected with a controller (16) having a memory and being programmable. The end switches (13, 14) detect a reference point in horizontal and vertical directions, and two end switches (11, 12) detect the rotations of the spindles (6, 8) as a measure of the distance travelled by the second cardanic joint (4).

Abstract: An elongated element, for example, a soot blower for the cleaning of wall surfaces, is guided along a predetermined, meandrical blow figure. The element is supported in two spaced-apart cardanic joints (3, 4) the first of which is stationary and the second axially moveable on a first spindle (6) the ends of which are axially moveable on two parallel second spindles (8). The first and one of the second spindles (6, 8) are each provided with two non-mechanical, inductive proximity switches or end switches (11-14) which are connected with a controller (16) having a memory and being programmable. The end switches (13, 14) detect a reference point in horizontal and vertical directions, and two end switches (11, 12) detect the rotations of the spindles (6, 8) as a measure of the distance travelled by the second cardanic joint (4). The impulses of the end switches.