An apparatus and process for monitoring fluid flow through a nozzle is disclosed. Such compositions are useful as an intermediate in the production of HFC-245fa and HCFO-1233zd. The first and second sets of fluid chambers are in fluid communication with sources of first and second fluids, respectively, the source of the first fluid being separate from the source of the second fluid. Within the outflow pipe is arranged a slide which is open on both end faces and which closes the inflow orifices of the outflow pipe in the longitudinal direction according to the position of said slide and forms a vertically adjustable overflow for the water flowing into the outflow pipe. Once the personal item is removed, the hook returns to its stored position.