BL401-3 Fused Tank-Top Sight Light

Integrated Light with a Fused Process Window

The Borlan Fluid BL401-3 fused tank-top sight light combines illumination and a process-facing observation window in a compact clamp-on assembly. It is intended for equipment designers who need to view the interior of a vessel through a tank-top port while keeping the light and window configuration clear in the purchasing specification. The fused, or sintered, version has a glass-to-metal process-facing construction; it should be distinguished from the conventional-window version when requesting a quotation.

For a reliable fit, confirm the connection size, mating ferrule, available installation height, supply voltage, power, cable entry, operating conditions and the exact window construction. Borlan Fluid can review the selected arrangement against a drawing before production.

Product View: Fused Window and Stainless-Steel Housing

How the Fused Version Differs

The product family can be supplied with different process-facing window constructions. In the fused version, the glass and metal are joined to form a smooth observation face. This construction is useful when a buyer wants a compact window and needs to review cleaning access around the wetted surface. The actual seal, surface finish and suitability for a specific cleaning procedure remain configuration-dependent.

The original photo below shows the fused window face. It is a construction reference, not a pressure, temperature or certification test report. If your project compares a conventional window with a fused one, state that choice explicitly in the RFQ.

Catalog Dimensions for BL401-3

The Borlan 2025 catalog lists two sizes for the BL401-3 fused clamp-on tank-top sight light. The following dimensions are in millimeters. The separate BL401-3D rows in the catalog describe a different, larger configuration and are not included in this BL401-3 table.

Dimension note: These values are catalog references, not a substitute for the approved drawing. Check the mating clamp or ferrule profile, gasket, cable clearance and final assembly envelope before machining the tank port.

Electrical and Operating Selection

The BL401-3/BL401-3D catalog family offers external 12–24 V input with AC/DC options and several light configurations. Specify the required supply type, voltage, power, light color, cable entry and cable length for this BL401-3 assembly. Do not select a driver or hazardous-area version from the family description alone.

For the fused process-facing window, the catalog instructs users to provide a soft contact seal and to limit heating and cooling to no more than 2–3°C per minute. Provide the complete temperature cycle, pressure or vacuum conditions, cleaning method and process medium so that the seal and window assembly can be reviewed for the actual duty.

Explosion-protection documentation is configuration-specific. A Borlan certificate for a BL401-3 sample identifies DC 12–24 V and 7 W, but the certificate is valid only for equipment consistent with its tested sample and drawings. Ask Borlan Fluid to verify whether the exact fused-window, connection, power and cable-entry arrangement you are ordering is covered by the applicable documentation. Other BL401-3 or BL401-3D options must be checked separately.

Where a Tank-Top Sight Light Helps

A tank-top sight light gives operators a dedicated illumination point for viewing through a vessel opening. It can be considered for mixing tanks, process vessels and other enclosed equipment where visual checks are part of the operating procedure. The choice of light, window and connection depends on the vessel layout, process media, cleaning cycle and any site classification. The sight light itself is not a substitute for a separate viewing window where the equipment design requires one.

Borlan Fluid manufactures sight glass and sight light assemblies and can help compare the required port size and observation arrangement. For a separate window component, see the BL-KGSJSJ-XX fused clamp sight glass. The two products serve different installation roles, so identify whether you need an illuminated tank-top unit, an independent viewing window, or both.

Questions Buyers Often Ask

Is the product image the fused version?

Yes. The main and detail photographs were selected from Borlan’s original set that distinguishes the conventional and fused process-facing versions. Confirm the exact supplied construction on the quotation and approved drawing.

What sizes are listed for this BL401-3 fused tank-top version?

The 2025 catalog lists 1.5-inch and 2-inch connections for BL401-3, with interface diameters of 50.5 mm and 64 mm. Both rows show L 20 mm, H 84 mm and Ød 37 mm. BL401-3D has its own dimensions.

Does the catalog dimension table establish a pressure rating?

No. It describes the installation envelope. Request a pressure or vacuum assessment for the exact fused window, seal, clamp and operating temperature. A rating stated for a different sight glass component should not be transferred to this light assembly.

Is every voltage or wattage explosion-protected?

No blanket coverage is stated here. The documentation must match the exact model, electrical configuration and assembly supplied for the project. Share the hazardous-area classification and required certification with the RFQ.

Request a BL401-3 Configuration Review

Send Borlan Fluid the 1.5-inch or 2-inch connection, mating ferrule drawing, fused-window requirement, supply type and voltage, power, light color, cable entry and length, process medium, pressure/vacuum, operating and cleaning temperatures, heating/cooling rate, seal preference, hazardous-area classification, destination market, quantity and required documentation. The team can review the details and quote a clearly identified configuration.

For product demonstrations and new sight-light examples, visit the Borlan Fluid YouTube channel. For a video of the exact size and construction under consideration, request a current recording with your quotation inquiry.