Inside the SplashValve: Why 316 Stainless Still Rules Under Pressure

In underwater automation, corrosion is the first and most persistent adversary. The SplashValve project faced it head-on with a housing designed for years of submersion, high flow and constant actuation—all without maintenance.

According to Ronn Garland, program director at ARM Automation’s SplashBotix division, the housing needed to survive in chlorinated water, handle pressure variation and protect sensitive electronics from intrusion. His team selected cast 316 stainless steel, impregnated to eliminate porosity and sealed to protect the internal control hardware.

Built for Depth, Designed for Durability

Garland explained that each design decision balanced cost, strength and corrosion resistance. He emphasized that long-term reliability in a submersible environment required a material able to resist both chemical attack and mechanical fatigue.

• Material choice. Cast 316 stainless steel offers superior pitting resistance compared with 304 or duplex grades—vital in chlorinated or brackish environments.
• Manufacturing approach. Casting enabled complex geometry while polymer impregnation sealed microscopic pores that could otherwise initiate corrosion.
• Mechanical integrity. After casting, precision machining preserved alignment for the spool assembly and ensured a leak-free interface at all static joints.

Garland noted that avoiding any shortcuts during sealing or finishing was critical to long-term submersible performance.

“The whole premise, the whole reason for the magnetic coupling was to get rid of any dynamic seals,” he said. “Dynamic seals over time fail, so we use magnetic to drive the spool through solid billet stainless…so there is no path to leak. There is no seal to wear.”

Smart Sealing: Eliminating the Weak Link

Traditional submersible valves rely on dynamic shaft seals that inevitably wear out over time. Garland identified this as one of the primary failure modes in underwater actuation systems.

The SplashValve design removes that weakness entirely by using only static sealing surfaces—all actuation passes through a magnetic coupling (this will be covered in Part 2).

Garland has described this approach as keeping water out by eliminating any motion through the pressure boundary, creating a fully sealed housing that protects the internal electronics for the life of the system.

A Systems Perspective

Garland characterizes the housing as a system-enabling component rather than a passive shell. Materials engineers focus on microstructure and corrosion; mechanical engineers care about tolerances; controls engineers depend on a stable internal environment.

By committing to 316 stainless and a seal-free envelope, Garland’s team ensured that every discipline downstream benefits from upstream material choices—an essential lesson for multidisciplinary design.

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