Reciprocating Seal Test Stand Built to Simulate Real-World Duty Cycles

Four-Station Reciprocating Seal Test Isolates Dual-Path Leak Failures

Seeking to simulate real-world failure modes for heavy equipment parts, a global manufacturer required a rigorous reciprocating seal test. ACS engineered an automated hydraulic test system and four-station test bench designed to compress months of duty cycles into weeks.

The Challenge

A large global equipment manufacturer wanted to develop a reciprocating seal test stand, to collect test data and simulate real-world conditions. The company sought a test bench that simulated how seals behave through reciprocating motion under varying loads and durations. The client’s existing testing was limited and didn’t provide enough insight into the longevity of seals under realistic duty cycles or their dominant failure modes under extended operation.

The project came to ACS from an internal referral within the manufacturer. With years of completed projects for the company, one of the divisions with first-hand experience working with ACS referred them as a trusted integrator with a strong track record working across its broader ecosystem.

The Solution

The client asked for a stand that could run realistic, long-duration seal tests that reveal where and how seals fail. ACS delivered a tightly integrated system that centralizes hydraulic power across four stations, each with independently oscillating pistons, allowing four seals to get tested simultaneously while under different test plans and duty cycles.

Using Self-Tuning Control to Achieve Separate Oscillation Rates for Each Test Station

All four test stations can run concurrently but can utilize different oscillation rates. The client provided the fixture that holds the test article within each station, where operators can load different spring combinations that control the resistance exerted on the piston.

The ACS engineers designed a self-tuning control since the spring variability could not be entered into the control system as a constant. Operators enter the known inputs into the Acselerant®-based control system, including the target oscillation frequency. At the start of each test, the system runs an automated sequence that adjusts hydraulic test system parameters until it reaches the target rate, then holds that frequency for the test’s duration.

Accurately Captures Leakage Rate of Two Separate Leak Paths

The client’s original requirement was to measure the total test fluid leakage. During the design process, ACS discovered that the client’s fixture has two separate leak paths. Instead of measuring total leakage, the company wanted each path measured independently.

The leakage rates are so low that an inline flow sensor would struggle to provide accurate readings. Instead, ACS pivoted to a mass-based measurement since it could capture the low flow without getting affected by temperature the way a volume-based system would. The ACS engineers designed a dual-tank system, one tank for each leak path, that captures leaked oil. Each tank sits on a load cell that tracks changes in weight over time.

By tracking those weight changes, the Acselerant system uses that data to:

• Back-calculate the average leakage rate for each path per test.
• Identify sudden leakage increases that could indicate a seal failure event.

These calculations are done automatically at various intervals. A system of safety interlocks, door locks, and stack lights designed by ACS, protect operators and flag over‑temperature or fault conditions without the hydraulic test system requiring constant supervision.

The ACS engineers also designed a heating loop for the hydraulic oil and band heaters are mounted around the fixture so seals are tested at in-service temperatures.

The Outcome

ACS delivered a software-controlled reciprocating seal test stand around the company’s test fixture that can simultaneously run four high-endurance, reciprocating seal tests under separate parameters.

The system supports long-duration test cycles that compress months or years of operation into weeks. Key design elements mirror real operating conditions, such as exercising the seals at representative temperatures, throughout the run.

With four tests running in parallel, each approximating a different set of real-world duty cycles, the test bench is positioned as a high-fidelity development tool for understanding seal longevity by capturing when and how seals fail, giving operators clearer insight into different failure modes.

This project marked ACS' first engagement with this division, reinforcing its same high standard of work across the company that earned the referral in the first place.

Key Features

• Single test bench with four stations running independent tests
• Dual-path leakage collection per station, independently capturing changes in ultra-low leak rates that indicate a failure event
• Structural decoupling between the oscillating test frame and the leak detection system to minimize vibration-induced error in leakage measurements
• Integrated hydraulic oil heating loop and band heaters around the fixture maintain oil and fixture temperature within scope of in-service conditions
• Interlocked access doors, over-temperature protection, and stack-light status indication enforces safe access and provides clear system status during long-duration cycles

ACS Services

• Reciprocating seal test stand design and engineering
• Control system design and integration (Acselerant)
• Data acquisition system design
• Electrical panel packaging and manufacturing
• Mechanical integration and assembly
• Factory and onsite acceptance testing
• Onsite commissioning support