Ruitang Patent | How to Achieve Stealth Effect for Mine Housings?

The Ruitang Patent column continues to interpret authorized patents of Ruitang Plastic Group. In our previous issue, we focused on the fitness equipment sector and introduced the invention patent for polyolefin composite materials specially used for rotomolded dumbbell plates. In this issue, we turn to marine special equipment and discuss an invention patent for one‑step rotomolded stealth mine housings.

Patent Full Name: A Stealth Mine Housing and Its Preparation Method

Patent No.: ZL 2019 1 0925611.X

In the underwater marine equipment industry, mine housings need to serve long-term in deep-sea environments with high pressure and heavy salt spray corrosion. Meanwhile, they must avoid detection by sonar, electromagnetic waves and other detection methods. With the advantages of one-piece molding, easy fabrication of hollow structures and excellent seawater corrosion resistance, rotomolding is an optional manufacturing process for special underwater housings. However, the industry has long faced multiple challenges in R&D and practical application:

▫️ Single stealth dimension: Traditional housings mostly only realize single electromagnetic wave stealth and cannot resist sonar detection synchronously, making them easy to be identified by multi-source detection systems.

▫️ Complicated processing of multi-layer housings: Traditional wave-absorbing / wave-transparent composite housings require separate molding and adhesive assembly of layers. The bonding strength at the interlayer interface is poor, and delamination and water seepage are prone to occur after long-term immersion in seawater, resulting in loss of stealth performance.

▫️ Impurities in materials interfere with wave-transparent performance: Ordinary PE raw materials contain relatively high content of metal ions, which interfere with electromagnetic wave penetration and weaken the wave-transparent effect of the outer layer.

▫️ Excessive self-weight of housings: Multi-layer bonded composite structures are heavy, which is unfavorable for underwater deployment and attitude control.

▫️ Difficulty in mass production: Multi-process composite processing brings high difficulty in yield control and high industrialization cost.

To address these industry pain points, the Ruitang Plastic Group R&D team leverages the property differences of rotomolding powder materials and developed this three-layer composite stealth mine housing that can be formed in one rotomolding process, which has obtained national invention patent authorization.Core Technical Highlights of This Patent

✅ One-step rotomolding for three-layer structure, no secondary bonding required. Self-layering during molding is realized by differences in powder particle size and surface tension. The interlayer bonding is tight to eliminate the risk of seawater penetration and delamination failure.

✅ Dual stealth performance against electromagnetic waves and sonar. The outer low-metal-ion polyethylene wave-transparent layer, middle wave-absorbing foam layer and inner low-melting alloy reflecting layer work synergistically to evade both electromagnetic and sonar detection.

✅ Outstanding resistance to marine environments. The polyethylene substrate resists seawater corrosion and salt spray aging, suitable for long-term underwater immersion. The foam structure reduces housing weight and facilitates underwater deployment.

✅ Simplified production procedures with fewer processing steps. Separate molding and bonding processes for multiple layers are eliminated, shortening the production cycle and improving product consistency.

✅ Compatible with rotomolding process for easy industrial implementation. Special composite housings can be manufactured based on mature rotomolding technology without complicated dedicated molding equipment.

✅ Hollow integrated housing structure with good structural stability. There are no assembly seams on the whole part, offering stronger structural reliability under underwater high pressure.Applicable Scenarios of the TechnologyScenario 1: Housings for stealth mine equipment

It serves as the main outer shell of mines. The integrated hollow structure can withstand underwater hydrostatic pressure, and the three-layer composite structure stably realizes dual stealth against electromagnetic waves and sonar. The material resists seawater and salt spray corrosion and can work for a long time in offshore and deep-sea environments, meeting the requirements of long-term lurking and concealed operation of equipment.

Scenario 2: Housings for underwater detection targets

Used for underwater simulation targets in underwater acoustic and electromagnetic countermeasure tests. The electromagnetic and acoustic signal characteristics can be adjusted as required to simulate the echo signals of various underwater targets. The rotomolded one-piece housing supports flexible shape customization and can be used for performance calibration and countermeasure drills of sonar detection equipment, underwater radar and marine monitoring equipment.

Scenario 3: Protective housings for special underwater sensors and beacons

Applied to the outer protective shell of underwater detection sensors, marine monitoring beacons and underwater acoustic recorders. While protecting internal precision electronic components from seawater corrosion and water pressure impact, it regulates the electromagnetic and acoustic signals of the housing and reduces the probability of the equipment being detected, suitable for concealed operations such as marine exploration and underwater monitoring.

Scenario 4: Auxiliary functional components for unmanned underwater vehicles

It can manufacture external stealth functional housings and fairings for small unmanned underwater vehicles. Benefiting from the high design freedom of rotomolding, it can be customized following the streamlined shape of underwater vehicles, optimizing acoustic and electromagnetic scattering properties on the premise of lightweight and helping improve the concealment of underwater platforms.

Scenario 5: Customized marine stealth rotomolded components

Custom multi-layer composite stealth rotomolded housing solutions are available for marine research institutions and special equipment manufacturers. The powder formula and housing thickness can be adjusted according to different water depth requirements, countermeasure standards and outline dimensions to rapidly develop non-standard underwater stealth components for cutting-edge underwater equipment R&D projects.Core Values for Customers

🔹 Integrated molding ensures long-term stable stealth performance. Unlike traditional bonded composite housings, the self-layered integrated structure avoids interlayer debonding risks. Its wave-transparent and wave-absorbing functions will not degrade rapidly after long-term seawater immersion to guarantee lasting and reliable stealth performance of underwater equipment.

🔹 Integrated multi-mode stealth. One single housing achieves dual stealth against electromagnetic waves and sonar, without additional external stealth coatings that may fall off and fail, satisfying the requirements of modern underwater countermeasures with multiple detection methods.

🔹 Lightweight housing improves underwater deployment performance. The foam composite structure reduces the self-weight of the housing, helps optimize the attitude of equipment, lowers the difficulty of deployment and expands the applicable water areas.

🔹 Streamlined manufacturing of special housings. Multiple molding and bonding assembly steps are removed, eliminating individual differences caused by manual assembly. The consistency of stealth performance among batches is improved and the cost for trial production and mass production of special equipment is reduced.

🔹 Material system adapts to harsh marine working conditions. The low-metal-ion polyethylene substrate has excellent seawater corrosion resistance and salt spray aging resistance, reducing the need for extra anti-corrosion coating and lowering later maintenance work of equipment.

This patent marks an extension of rotomolding materials from civil products to high-end marine special equipment. It also reflects Ruitang’s continuous efforts in functional rotomolding composite materials. Centered on real application scenarios, Ruitang’s R&D combines formula innovation with rotomolding process innovation to overcome technical bottlenecks of stealth, corrosion resistance and integrated molding for special underwater housings, empowering the marine equipment industry with rotomolding materials.

The Ruitang Patent column will keep updating. Stay tuned for our next patent interpretation.

If you have practical experience or questions about the development of special rotomolded housing materials and selection of rotomolding powder formulas, welcome to leave a comment and discuss with us.