High Safety Process Flow Cell

GUIDED WAVE recommends the use of our High Safety Flow Cell (HSFC) for applications involving extremely hazardous materials. When processes involve extremely toxic or hazardous materials such as hydrofluoric acid, phosgene, isocyanates, etc., safety is paramount. Uncontrolled or undetected leaks cannot be tolerated. Guide Wave’s patented High Safety Flow Cell was designed with leak prevention and early detection in mind. Built into a Class 300 flange, using welded construction, the HSFC uses double o-ring sealed sapphire windows. A weep or “tattletale” port connects to the space between the o-rings and when coupled to a sensor, can indicate o-rings in need of replacement. The HSFC is available in a variety of alloys and o-ring materials selected to be compatible with your process.

High Safety Process Flow Cell Features

  • Suitable for extremely hazardous sample streams
  • Built into a ½” class 300 flange
  • Patented Double o-ring sealed design
  • Safety sniffer port provided between o-ring seals. This allows connection to a leak detection system to be used as an indicator of primary seal failure
  • Compatible with all Guided Wave analyzers and many other analyzer brands
Multi-Purpose Process Flow Cell (Heated Version)

Safety Features

As a patented (US Pat #5,452,082) safety feature, each sapphire window is double o-ring sealed. A passage from between the o-rings is brought to a common port terminated in a ½” Class 300 flange. It is highly recommended that a sensor sensitive to the process material be attached to this port with its alarm set at an appropriate level. An alarm condition would indicate that the first o-ring seal has failed and that immediate o-ring service is required. The second o-ring seals the process until the required service is accomplished.

Welded construction is used to connect the warning port. All HSFC’s are hydrostatically tested prior to delivery.

Design Features

The High Safety Flow Cell is a 2.25” thick, 1” Class 300 flange with double o-ring sealed sapphire windows. Precision mounted collimating lenses and fiber optic (SMA 905) connectors complete the optical design. Hardware is provided to connect protective conduit for the fiber optic cables. Standard optical pathlength are 20 mm and 30 mm. Other pathlengths are available by special request. Standard construction is 304 stainless steel; other alloys are available.

The early warning leak port is terminated in a ½” Class 300 flange. O-ring material must be specified by the customer to ensure process compatibility. Please consult appropriate resources for temperature specifications of various o-ring materials and chemical compatibility with your process.

The High Safety Flow Cell can be dismantled for o-ring replacement and cleaning. Repeatability of the pathlength on re-assembly is ensured by the design. Additional o-rings are used to prevent infiltration of environmental contaminants such as water, vapor, and dust.

Figure 1: High Safety Flow Cell Drawings (HSFC)

High Safety Process Flow Cell Drawing

Specifications: High Safety Flow Cell (HSFC)

Product NameHigh Safety Process Flow Cell
Part Number
Body Material304 SS (standard) ASME specified materials having yield strengths of 30 kpsi or greater at ambient temperature
O-Ring MaterialKalrez® 4079, Kalrez® 2035, Viton, EPDM, Silicone, Customer requested elastomer with a Durometer >70 and Shore of A or greater
Window MaterialSapphire
Pathlength20 mm, 30 mm, Customer requested, subject to acceptance
Fiber TerminationSMA 905
Optical BeamCollimated
Maximum Pressure<300 psig [2000 kPa] (hydrostatically
Maximum Temperature150 °C [300 °F]
Flange (Body) Specification1 inch Class 300 x 2.25 inches [57.2 mm
Flange (Leak Port) Specification½ inch Class 300; MUST BE CONNECTED
Optical Efficiency>45% Transmission from 800 nm