There are basically three types of nozzles: ISA 1932 nozzles, long-radius nozzles and Venturi nozzles. Depending on the application, each design has its advantages. In the following we briefly present the three designs. All variants can be designed as single-flange nozzles or weld-in nozzles, see the relevant brochures on the right.
Standard nozzles consist of a rounded inlet profile and a cylindrical neck section. The sampling is carried out via individual bores in the one-piece casing ring or via annular chambers in the two-piece casing ring.
Depending on the application, the measurement uncertainty is approx. 0.8% – 1.2% of the flow coefficient.
Long radius nozzles consist of an inlet profile, which corresponds to a quarter ellipse, and a cylindrical neck section. The sampling is carried out on the pipeline at a distance of 1D upstream of the nozzle and 0.5D downstream of the nozzle (D= inner pipeline diameter).
Depending on the application, the measurement uncertainty is approx. 2% of the flow coefficient.
Venturi nozzles consist of a rounded inlet profile, a cylindrical neck section and a diffuser (outlet cone). The positive pressure tapping is normally carried out via a single tapping hole. The negative pressure tapping is normally carried out with four tapping holes which lead into a ring chamber/ring line.
Depending on the application, the measurement uncertainty is approx. 1.2% – 1.8% of the flow coefficient.
Typical types of discharge nozzles are:
For high pressures and high temperatures, it is advisable to use a nozzle for welding in to prevent leaks. All three designs can be manufactured as weld-in variants. On request, pipe ends, usually provided, can also be welded on at the inlet and outlet. In this case, the weld seam is machined on the inside after welding in order to guarantee the requirements of the calculation standard for the pipe condition. For details see the brochures on the right.
Nozzles can be equipped with shut-off valves and/or valve blocks. Condensate vessels are recommended for steam applications.