Watertight Tester

The automatic watertight testing system is purpose-built for end-of-line sealing inspection of rotationally molded (roto-molded) PE fuel tanks and other hollow roto-molded parts.

It quickly and reliably detects defects such as micro-pores, parting-line leaks, and leaks at embedded threaded inserts on the production line, ensuring products are free from leakage and seepage.

The system supports two mainstream test methods:

● Bubble-test method (immersion leak test): Low-pressure compressed air is injected into the tank, which is then fully submerged in a water tank; escaping bubbles visually pinpoint the leak location.

● Hydrostatic pressure test: Water is filled and pressurized inside the tank to verify pressure resistance and watertight performance; suitable for standard tests such as marine fuel tanks.

An optional differential-pressure airtightness tester enables dry leak testing without immersion, meeting high-cleanliness requirements.

● Solves the flexible-shell expansion challenge: A built-in anti-bulge support frame limits tank swelling and prevents rupture during air/pressure loading - essential for large marine roto-molded fuel tanks.

● Reliable, quick-change port sealing: Quick-clamp sealing plugs with oil-resistant silicone O-rings and integrated air/water channels; plug modules are interchangeable for multiple tank sizes, so one fixture covers many products.

● Automated immersion solution: Two frame layouts - "fixture descends into water" and "water tank rises to submerge" - paired with overflow troughs, water circulation, and waterproof lighting for clearer bubble observation and easier operation.

● Multi-method compatibility: Integrated bubble (airtight immersion), hydrostatic (pressure), and differential-pressure (dry) leak testing, flexibly selectable as needed.

● Complies with marine standards: Standard test pressure 0.02-0.05 MPa (20-50 kPa); marine fuel tanks can be tested per ABYC at 3.5 PSI; the test process is recordable and traceable.

● Modular and expandable: Plugs, frames, racks, and control units can be flexibly combined to match production tact time and product specs, allowing easy future expansion and upgrades.

Adapt to filler necks, sensor flanges, inlet/outlet ports, and vent ports; quick-clamp structure with oil-resistant silicone O-rings and integrated air/water channels, connected to external air supply or booster pump; optional quick-couple (eccentric/cam or pneumatic clamp) or threaded plugs.

The basic version is an external limiting frame (square-tube welded with limit blocks); the premium version is a profiled clamping cavity (upper/lower dies conforming to tank shape, pneumatically clamped) that effectively limits expansion deformation. Mandatory for large marine roto-molded fuel tanks.

Option A: Fixed water tank + lifting bracket - the fixture clamps the tank and descends into the water. Option B: The tank is fixed while the water tank rises to submerge the product. Equipped with overflow trough, water circulation, and waterproof lighting for bubble observation.

For bubble (airtight immersion) testing: pressure regulator, pressure gauge, and hold-time timer. For hydrostatic/pressure testing: electric booster pump, pressure acquisition, and relief protection. Optional differential-pressure airtightness tester (dry leak testing).