Precision Static Mixer

Product Overview

The precision static mixer is a small-bore inline mixing device built specifically for the metered dispensing of two-part reactive chemistries — epoxies, polyurethanes, methacrylates, silicones, polysulfides, and the family of structural adhesives used in automotive, electronics, aerospace, and medical-device assembly. It is a direct evolution of our industrial static-mixer line, redesigned around the unique demands of low-flow, high-precision dispense: short mix length, clean disassembly, low dead volume, and a housing that can be specified either as a reusable stainless assembly or as a disposable cartridge that is discarded at end-of-life.

Inside the housing, 12 to 32 right-hand/left-hand helical elements (SS316L for the reusable line, PP or PA66 for the disposable cartridge) are stacked in alternating rotation. Each element forces the stream to split, rotate 180°, and recombine with its neighbor; the cumulative effect over 24 elements is approximately 4 million theoretical sub-streams, which is what allows the mixer to deliver a coefficient of variation of 1% or better on the discharge — well inside the cure-window of even the most ratio-sensitive two-part systems.

Compared to dynamic (impeller) mixers used in the same service, the precision static mixer has no moving parts, no seals to wear, no electrical power, and an order-of-magnitude lower purge volume. The trade-off is that it cannot compensate for ratio error upstream — if the metering pumps drift off-ratio, the discharge will follow. For that reason, the mixer is designed to be paired with positive-displacement or gear metering pumps whose accuracy is independently verified, and the system-level design assumes a 0.5-1% pump accuracy as the floor for the achievable end-of-arm mixing precision.

Three product variants cover the bulk of the application space. The standard reusable stainless mixer is the workhorse for high-volume production cells where the dispense volume per shift is large and the cost-per-shot of a disposable cartridge is uneconomic. The disposable cartridge is the choice for low-volume or multi-chemistry cells, for pre-mixed-and-frozen applications, and for any process where cross-contamination between batches is unacceptable. The medical-grade variant adds a Class VI / USP <87> biocompatibility certification, gamma-stable construction, and a 100% lot-traceable element set.

Design Features & Working Principle

The mixing elements are pressed from 0.4-0.6 mm SS316L sheet (or injection-molded PP/PA66 for the cartridge variant) into a four-vane helical form. Each element has an outer diameter of 4.7-9.8 mm depending on the housing size, with a vane twist of 180° over the element length of 3.0-5.5 mm. Elements are stacked alternating R-H and L-H so that each joint is a 90° turn, and the cumulative twist over a 24-element stack is 12 full 180° rotations.

As the two metered streams enter the housing, they are immediately subdivided by the first element into four quadrants. The 90° turn at each element joint forces the quadrants to cross over into the adjacent channel; the next element then splits each quadrant again, producing 16 sub-streams. By element 12, the cross-section contains approximately 4,000 sub-streams; by element 24, the count exceeds 4 million. The residence time through a 24-element housing is on the order of 0.2-0.5 s at typical dispense rates, which is short enough to prevent premature reaction in most two-part systems (typical pot life > 30 s at dispense temperature).

The housing itself is a precision tube with an internal surface finish of Ra ≤ 0.8 μm. End connections are machined from bar stock and welded to the tube by orbital TIG; the welds are passivated and dye-penetration-tested before assembly. For the disposable cartridge, the housing is a single injection-molded PP or PA66 part with integral male/female luer or UNF thread, and the elements are ultrasonically welded in place — the entire cartridge is then bagged in a nitrogen-purged foil pouch for shelf life of 18-24 months at room temperature.

Three options that frequently matter in dispense applications: bayonet-mount cartridges for quick-changeover in production cells (change time < 5 s); integral static mixers with a purge port for color-change or chemistry-changeover with zero disassembly; and low-residence ("dead-volume") tips that reduce the wetted volume between mix point and dispense tip to as little as 0.05 mL — important for shot sizes in the 0.1-1 mL range where every microliter of internal volume is material wasted at the end of a run.