Bubble Trap

Sight Glass available in six standard sizes that provide viewing areas ranging in size from approximately 3″ to 9″ in diameter. The weld-on assembly is designed to provide direct visual inspection of process vessels, separators, silos, pipelines and storage tanks. To illuminate the interior of the vessel, ...

LumiStar® 1000 LED Luminaire Series USL13/33

This light is an extremely reliable sight glass luminaire. Resistant to shock and vibration.

ApprovalsETL listed for all 12-24V and 110-240V with standard cable connectionCE compliant for all 12-24V configurationsProtection:Conforms...

MetaClamp® Sanitary Sight Glass WindowThe strongest, most secure sight glass elements available, METAGLAS®  mechanically prestressed windows, are available in a sanitary design for process applications.

Unlike some other sight glasses, METAGLAS® sight glasses meet the USP Type 1 standard fo...

Sterile View Thru Flow Indicator for Hygienic Applications A flow indicator designed to be mounted in-line for high purity applications to provide operators with a clear view of flow of virtually any process pipeline fluid or powder. The sterile-designed flow indicator features an internal-flush style that...

The ability to see what is happening inside a pipe can be invaluable to process operators. Despite technological advances, no sensor can equal the human eye which has more than 94 million photo receptors. 

Process observation equipment falls into two major categories: sight glasses, also called sight glass windows, which are used on process vessels, and sight flow indicators, which are used in process pipelines. This white paper covers the latter. (For information on sight glass windows, see our Chemical and Pharmaceutical Sight Glass Application Handbook.) 


A sight flow indicator is a device installed in a pipe to provide a visual means of verifying liquid flow for direction and approximate rate. Simple and low-cost, it also allows operators to observe the color and clarity of process fluids through a window. 

Sterile Visual Flow Indicator for Pharmaceutical Processing

LJ Star's innovative Clamp Type Sterile Visual Flow Indicator (CT-SVFI) is a patent-pending solution designed to eliminate contamination in pharmaceutical processing. 

Featuring sanitary clamp-based assembly instead of traditional threads, this product delivers precise o-ring compression that prevents bacterial contamination, bacterial buildup, and cleaning challenges. With a 34% larger viewing area, 316L stainless steel construction, and available in sizes 1/2" to 4", it's certified for FDA, USP Class VI, and European standards. 


Perfect for pharmaceutical, biotech, and food/beverage processing applications requiring reliable in-line process monitoring.

LJ Star is a trusted supplier of visual process monitoring solutions for the pharmaceutical industry. We specialize in FDA-compliant illumination systems, sterile visual flow indicators, and inspection-grade sight glasses. Our products are designed to enhance process visibility while maintaining the highest contamination control and safety standards.