Project Description

Style S Sight Flow Indicator

This sight flow indicator is ideal for you to visually check the flow, presence, colour and condition of a liquid.

  • Screwed and flanged connections
  • Highly visible PTFE spinner
  • CE marked and fully PED compliant
  • High temperature and pressure ratings
  • Short lead times
  • Designed and manufactured in the UK


With the highly visible PTFE spinner the style S sight flow indicator is used to check the flow of a liquid in a pipeline. It can be used in vertical or horizontal lines and is ideal for flow monitoring in full pipes.


The standard bodies are cast in either carbon steel or 316 stainless steel, though we can produce them in other materials.
The glass windows are held in place by stainless steel covers and screws, and sealed with PTFE gaskets, giving superior protection. For ease of maintenance the glasses can be in individually removed and replaced.
For standard applications the indicator is fitted with toughened soda lime glass discs to BS3463 and rated to 16 bar.
For steam and condensate we recommend toughened borosilicate glass, while for alkaline liquids mica discs can be used to protect the glass.
The sight glasses can be supplied with screwed connections to NPT, BSP parallel or taper. The standard flanges available are ANSI 150, ANSI 300 and PN16, though other flanges can be supplied.


Primary Flowpoints stock carbon and stainless steel, but can supply sight glasses in special materials such as super duplex, hastelloy or low carbon steels.
High pressure toughened soda lime to BS3463 rated to 40 bar or 60 bar depending on the size, toughened borosilicate to BS3463 or DIN7080 rated up to 16 bar. Higher pressures are achievable by reducing the viewing diameter. The high pressure range uses powder coated mild steel covers as standard. Stainless steel covers are available as an option.
Graphite gaskets are available if required.
We can also offer A4 stainless steel fasteners when necessary.


All Flowpoints indicators are manufactured to the highest standards.
The quality system is independently audited by BSI and certified to ISO 9001. The indicators are fully PED compliant and CE marked where required. TUV are our external auditors for the Pressure Equipment Directive.
Full material traceability is maintained, material certificates and pressure test certificates are supplied on request.

Specification Code

Materials of Construction

– Stainless steel ASTM A351 CF8M (316)
– Powder coated mild steel grade S355J2+N
Internal Gasket
External Gasket
– Klingersil C4400
Edge Protector
– Klingersil C4400
– (Standard) – A2 Stainless steel
– (High Pressure) – High tensile steel
– Glass filled PTFE