Hanna Instruments O-Ring for BL10x/BL12x/BL13x Flow Cell (BL120-604)

Hanna Instruments o-ring for BL10x/BL12x/BL13x flow cell (BL120-604)

The BL120-604 is a replacement sealing O-ring for the flow cell used on Hanna Instruments BL10x, BL12x and BL13x series analytical controllers and dosing pumps. It sits between the flow cell body and the electrode or cell cap to keep the measuring chamber watertight under line pressure. It is a standard wear part in commercial pool water treatment installations.

What it fits

Designed for the flow cell assemblies fitted to the Hanna Instruments BL10x, BL12x and BL13x controller and dosing pump families. It is the original manufacturer sealing ring, so the cross-section and inner diameter match the flow cell seat exactly. Using a generic O-ring of the wrong size risks leaks or a crushed seal when the cell is tightened.

Fitting position

The O-ring seats in the groove of the flow cell where the electrode holder or cell cap screws down. Depressurise and isolate the sample line before opening the cell, then remove the old ring, clean the groove of scale and debris, and fit the new ring dry or with a trace of silicone grease. Hand-tighten the cap evenly to avoid pinching the seal.

Service life

O-rings harden and lose elasticity over time through contact with chlorinated pool water and UV or heat exposure. Replace at every electrode change, or immediately if you see weeping around the flow cell, flattening of the ring, or surface cracking. Keeping a spare on the shelf avoids downtime on the measuring loop.

Ordering notes

Supplied as a single O-ring, not as a complete flow cell service kit or with an electrode. Check which flow cell version is fitted to your controller before ordering, and consider buying more than one if you maintain several dosing lines.