The ACI type 551 sight flow indicator is a robust indicator designed for industrial applications.
The body is made of high-quality 1.4408 cast stainless steel, ensuring excellent corrosion resistance and high mechanical strength.
The design features internal BSP or NPT threads, allowing for the visual observation of fluids in pipelines under operating pressure.
Type 551 is manufactured in accordance with DIN 11869 (formerly DIN 3237).
Threaded connections
- BSP threads according to DIN EN ISO 228-1
- NPT threads according to ANSI B 1.20.1
TECHNICAL DATA – Type 551 Sight Flow Indicator
| Flange Material: | Stainless Steel – 1.4408 Other alloys according to customer specifications |
| Form: | Flow Sight Glass |
| Gaskets: | Frenzelit novaphit® MST XP KlingerSil® C4400 Garlock Gylon® PTFE (pure or modified) More than 50 other sealing materials available upon request |
| Nominal Size (NPS): | ¼” – 2″ |
| Nominal Pressure (PN): | PN16 – PN40 |
| Temperature / Glass: | up to 280 °C with borosilicate glass DIN 7080 |
| Options: | Mica protection disc for temperature and steam PTFE rotor |

















