Sight Tubes
Principle
Traditionally, liquid levels in tanks were monitored using glass sight tubes attached to the top and bottom of the tank. The liquid would rise in the tube to match the tank’s level, allowing easy reading. However, due to safety concerns, glass sight tubes have been replaced with magnetic sight tubes, which are more robust and safer for staff.
In this system, a stainless-steel tube replaces the glass, making it completely opaque. Inside, a magnetic float moves with the liquid, flipping metal tags from silver to red as it rises or falls, providing a clear and highly visible level indication without requiring power.
Advantages
- Suitable for all compatible liquids
- Can be equipped with additional magnetic switches or pressure transmitters
- Provides a large, clear indication
- Operates without power
Disadvantages
- Not suitable for solids
- Only side-mountable
- Requires two tapping points, even for unpressurised vessels
- Must be custom-made for specific applications and liquids
