A Deep Dive into the Materials, Mechanics and Control Systems of the SplashValve Submersible Robot

ARM Automation’s SplashBotix division has developed a compact, low-voltage submersible proportional valve intended for continuous underwater use in environments such as swimming pools and ocean water. Unique in its design, the device integrates magnetic coupling, fluid dynamics and robust materials selection to achieve precision control with high reliability and minimal maintenance.

Machine Design spoke with Ronn Garland, program director, at the company to learn about the major components and subsystems of the SplashValve with an emphasis on engineering principles, material choices, functional integration and testing methodologies.

Housing and Sealing System

The valve housing is constructed from cast 316 stainless steel, which was selected for its corrosion resistance and mechanical strength in aquatic environments. Casting is followed by impregnation with a proprietary polymer that fully seals porosities inherent in cast metals, thereby preventing water ingress. Garland noted the important role of seal elimination: “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.”

Cable entry points are sealed using a full potting break, which Garland said is to ensure resilience against water migration even if cable damage occurs during installation or use. “Even if the cable is nicked or cut during installation, water can’t migrate up the cable jacket or the internal conductors into the SplashValve,” he said, noting that this structural integrity enables long-term reliable operation under pressure and chemically aggressive conditions involving chlorinated or saline water.

Magnetic Coupling and Actuation System

The SplashValve replaces traditional mechanical shaft penetration with a magnetic coupling between a miniaturized servo motor inside the housing and the rotating spool valve. This contactless torque transfer avoids the typical wear and leakage challenges posed by dynamic seals. Garland said, “We packaged a very small servo and a control system that we magnetically couple to the fluid path, which is a moving spool. We run a complicated software so that we can hold the position of that spool to the exact degree that the system controlling it desires.”

The embedded servo receives low-voltage power and digital control signals via DMX512 protocol over a combined underwater power-data cable. The internal microprocessor implements a closed-loop PID, compensating for magnetic coupling characteristics.

“With any magnetic coupling,” Garland said, “there’s going to be a bit of a wind-up. We have proprietary software that accommodates that magnetic coupling…so you don’t have to worry about that seal failing.”

Kevlar-reinforced belts within the actuation train deliver wear-resistant torque transmission compatible with continuous duty cycles, Garland added.

Spool Valve and Fluid Dynamics

The spool valve, constructed from self-lubricating polymers rotates 90 deg., redirecting water flow either to the nozzle or a bypass channel, effectively modulating water output without interrupting flow, Garland said.

Its full-bore design supports passage of objects up to approximately 1 in. dia., minimizing clogging potential. Fluid pressure is balanced by design around the spool’s circumference and axial ends, producing negligible torque from hydraulic forces. This pressure equalization reduces actuator load and enhances positioning accuracy.

An adjustable calibrated orifice can be inserted into the bypass during installation to normalize manifold pressures, ensuring consistent nozzle performance across multi-valve fountain systems.

Bearings and Wear Components

Oil-impregnated nylon bearings support smooth, low-friction spool rotation without the need for lubrication service, Garland explained, and the Kevlar belts extend mechanical longevity and stability of the drive train under continuous operation.

“The SplashValve needs to be a device that is installed and then it just lives its entire life as it shipped from the factory,” Garland said. “Everything internally was designed to last the entire life of the product,” adding that empirical testing indicates no measurable wear after more than 24 million actuation cycles, supporting a design target of five or more years of maintenance-free service under typical operating conditions.

Electronics, Power and Control

The valve’s embedded electronics integrate power management and communication functions into a single compact system. Low-voltage power input is buffered by onboard capacitors that supply the required actuator bursts, smoothing demand on the facility power supply. “We bring in power at a very low voltage…and we charge capacitors within the SplashValve,” Garland said. “That is what the SplashValve actually operates on.”

This internal energy buffering optimizes external power demands. “While we may be using more power internally, the input power from the feed supply…never actually sees that full demand, because we spread the demand over time,” he said.

DMX512 digital control provides an industry-standard 8-bit communication channel per valve, facilitating straightforward scaling to hundreds of units in complex fountain systems. Control responsiveness is proportional to data input rates, enabling precise dynamic water shows.

Installation, Retrofit, Serviceability, Testing & Validation

The SplashValve installs beneath fountain nozzles utilizing pre-existing conduit typically intended for lighting, facilitating retrofit of static fountains into programmable dynamic water features. “You can remove the nozzle, put the splash valve where the nozzle was, then put the nozzle back on the splash valve and use existing conduits,” Garland said. Supported wiring architectures include star, home-run and planned daisy-chain topologies for installation flexibility.

Routine maintenance Is simplified through a custom toolkit that allows quick spool removal for cleaning without requiring disassembly of the entire valve or specialized equipment, which helps field servicing primarily to remove debris. “…Pull a pin, remove the pressure plug and pull the spool for flushing,” Garland said.

A rigorous development and quality assurance process underpins the valve’s design, including:

Initial prototyping and first-article testing refined mechanical and control system integration.
Valves undergo vacuum decay leak detection tests.
Continuous underwater cycling in test pools simulates extended real-world operation.
Additional tests include containment exposure, elevated temperature endurance and mechanical stress simulations.

Collectively, Garland says these tests demonstrate component durability, sealing performance and control accuracy under aggressive environmental conditions. “We do vacuum decay testing on every valve before shipment…then put a subset in our test pool for real-world cycling with dirt and temperature extremes to simulate the harshest environments,” he said.

Expanding Applications and Innovations

Although the SplashValve exemplifies how multidisciplinary engineering with a range of components and iterative validation yield reliable submersible systems that are adaptable for architectural, industrial and potentially marine robotic applications, ARM Automation is looking ahead and actively developing new variants of the technology—this time aimed at expanding its applicability beyond traditional fountain installations.

Garland said they are working on a smaller-scale robotic actuator designed for children’s playground water features, which incorporates magnetic coupling principles to create an intrinsically safe mechanism: should an obstruction like a stick or a finger enter the actuator, the magnet will slip before causing damage or injury.

Beyond playground applications, Garland says the company is developing a high-torque underwater actuator intended for more demanding uses, potentially including ocean exploration robotics and other subsea industrial applications. This effort builds upon their experience with large-scale fountain robotics, tailored for environments requiring robust waterproof actuation with precise control.