Within closed pipework or pressure tanks, it can be helpful to install sight flow indicators to visually monitor and control the media. The sight flow indicator allows you to monitor the direction of flow, and to check for foreign particles, which could damage the machine or the application. That makes the sight flow indicator perfect for visual monitoring, for example in a round, oval or rectangular shape. The construction resembles DIN 28120 or DIN 128121, which allows for easy welding. NieRuf is your partner for high-quality sight flow indicators.
flange sight flow indicator version with flap type FS01 made of grey cast iron GG25, soda lime glass and seal graphit DN80 - 3" Inch flange ANSI 150 16 bar
flange sight flow indicator DN25 design with PTFE-spinner Typ FS01 grey cast iron GG25 borosilicate glass graphit max 16 bar
flange sight flow indicator 3/4" GS - C25 Typ FS02 soda lime glass max 16 bar design with PTFE-spinner
flange sight flow indicator version with flap type FS03 made of stainless steel 1.4408, borosilicate glass and seal graphit DN32 - 1 1/4" Inch flange ANSI 150 16 bar
flange sight flow indicator version with flap type FS03 made of stainless steel 1.4408, borosilicate glass and seal graphit DN20 - 3/4" Inch flange ANSI 150 16 bar
flange sight flow indicator DN40 soda lime glass Typ FS01 grey cast iron GG25 graphit max 16 bar design with PTFE-spinner
flange sight flow indicator DN200 design with PTFE-spinner Typ FS01 grey cast iron GG25 borosilicate glass graphit max 16 bar
Sight glass fitting BS01 DN125 - 5" Inch aus stainless steel 1.4571 to be welded directly to tank seal NBR glass borosilicate glass 2,5bar
The flange sight flow indicator has to comply with a variety of guidelines, norms and requirements. We provide DIN 3237 valves from stock, whether you need borosilicate glass DIN 7080 or soda lime glass DIN 8902. The choice of the glass depends on the temperature or the media and the surrounding, as well as the pressure range of the media. Depending on the media, the sight flow indicator will be made from stainless steel (1.4408/V4A), brass or cast steel. Depending on the pipeline system, we provide sight flow indicators with flange or thread connection in sizes DN15, DN20 up to DN65 and DN80 up to DN200, or, for fast assembly with a female thread from ¼“ to ½“ and up to 2“ from stock. Please contact us for irregular sizes and special design.
Sight flow indicators are usually built into a pipeline system as flange sight flow indicators. Visual monitoring can be made easier by using a flap or a PTFE spinner, which move when there is flow. Container flow indicators however, are usually used within closed containers such as boilers, oil tanks and silos. This enables you to visually monitor the filling level. Please contact us if you need any help finding the right sight flow indicator, or simply order your sight flow indicator at low price and with fast delivery from our online shop.
Special requests, spare parts or a quick support? Our staff will answer your questions and concerns immediately.
Mon. - Fri. from 08:30 - 17:00
Phone: +49 7143/9666-901
sales@nieruf.com
Commitment engenders trust. We stand by our word and are convinced that as a result not only our customers but also everyone we work with can rely on us.
We always strive to find the best solution for our customers. It is our goal and incentive to have completely satisfied customers.
Technical and commercial expertise form the basis for developing qualified solutions tailored precisely to the needs of our customers.
We do not adhere to rigid guidelines but instead focus on the individual wishes and needs of our customers. They are more important to us than internal company processes.
Contact For all questions we are available by phone
Mo - Fr 08:30 - 17:00
or send us an e-mail:
Resistance check 
Frequently asked questions 
Configurator 
Angle seat valves
Ball valves
Butterfly valves
Check valves
Coaxial valves
Compensators
DISCO check valves
Diaphragm valve
Flow control valve
Gate valves
Globe valves
Knife gate valve
Manometer gauge valve
Needle valves
Overflow valves
Pressure reducing valves
Safety valves
Sight glass
Solenoid valve
Stainless steel hoses
Strainer
Thermally activated shut-off valve
Vent-valve
Need help?
If you have any questions, we are available by phone from Monday to Friday from 8:30 a.m. to 5:00 p.m.
order via mail:
