Primary Flowpoints Ltd

Primary Flowpoints Ltd

Primary Flowpoints Ltd, Charles Street, Walsall, WS2 9LZ. UK

Style P Sight Glass

Style P Sight Glass


The style P sight glass has a plain spout cast in the body and is used to check for the presence of a liquid where there is intermittent flow, partially filled lines or entrained air. It can be used in vertical or horizontal lines. The integral drip lip makes it ideal for leak detection.


The standard bodies are cast in either; carbon steel, 316 stainless steel or LG2 gun metal, 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 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 special flanges can be supplied.



Primary Flowpoints stock carbon, stainless steel and gun metal, but can supply sight glasses in special materials such as super duplex, hastelloy or low carbon steels. For particularly corrosive applications the body can be lined with PFA.


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, though stainless steel covers are available.


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.

Product Enquiry

SSL Secure Connection