Retractable assembly

摘要

A retractable assembly, comprising: a housing; an immersion tube, which is axially movable between a service position and a process position. A first inlet facing away from the medium and a second inlet facing the medium. The immersion tube is moved from the service position to the process position by supplying the first inlet with energy, and the immersion tube is moved from the process position to the service position by supplying the second inlet with energy. A first mechanical blocking member shifts against a spring bias, and the blocking member engages in a first groove on the immersion tube. The first groove is located in the movement direction. The spring bias is so embodied that supplying the second inlet with energy releases the blocking member from the groove, whereby movement of the immersion tube from process position to service position becomes possible.

主权项

1. A retractable assembly for immersion-, flow- and appendage-measuring systems in analytical process technology for measuring at least one measured variable of a medium, comprising:
a cylindrical housing; an immersion tube with a piston, wherein said immersion tube is axially movable between a service position run out from the medium and a process position run into the medium by means of a pressurized air, wherein at least a first inlet and a second inlet are provided on said cylindrical housing, wherein said first inlet is located on a side of said piston facing away from the medium and said second inlet is located on a side of said piston facing the medium, wherein the immersion tube is moved from the service position to the process position by supplying said first inlet with the pressured air, and wherein said immersion tube is moved from the process position to the service position by supplying said second inlet with the pressurized air; at least a first end position detent secured to said cylindrical housing for holding said immersion tube in the process position; a first shifting element provided, at an immersion tube end region facing the medium, which is so embodied that, in the case of moving of said immersion tube from the service position to the process position, and a first mechanical blocking member shifts essentially radially against a spring bias, wherein: said first mechanical blocking member engages in a first groove on said immersion tube, whereby movability of said immersion tube is blocked; said first groove is located in the movement direction from the service position to the process position behind said first mechanical blocking member; and said spring bias is so embodied that supplying of said second inlet with the pressurized air directly releases said first mechanical blocking member from the groove, whereby movement of said immersion tube from the process position to the service position becomes possible.