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Technical Solution for Military Standard Rain-Exposure Test Chamber

Project Background

The rain‑exposure test system of the military‑standard rain‑test chamber is designed in accordance with… GJB 367A-2001 “General Specification for Equipment Communication Devices” , GJB 150.8-1986 and GJB 150.8A-2009: Test Methods and Requirements for Rain Exposure of Military Equipment , a comprehensive and standardized rain‑exposure test for military equipment. The system comprises three procedures: Procedure I (rainfall and blowing rain), Procedure II (intensified conditions), and Procedure III (dripping water).

Military Standard Rain Test Chamber – Illustration

Scheme Overview

[Wind Speed Adjustment Range] The fan inside the test chamber can generate airflow velocities ranging from 5 to 18 meters per second, with an allowable wind speed tolerance of ±5%. The air source shall be oriented relative to the test specimen such that the airflow can be directed at a 45-degree angle from the horizontal and uniformly impinge on one side of the specimen.

The rainfall apparatus consists of a lifting mechanism and a drip‑rain tray. A controller allows users to program the test sequence, enabling automatic switching among three operating modes: rain exposure with an air‑blowing source, and automated rainfall at a distance of 1 meter from the sample surface. The drip‑water tank has an effective dripping area of 5000 × 5000 mm, with pinhole spacing of 20 × 20 mm. The tank is fabricated from stainless steel.

[Nozzle Parameters] The nozzle diameter is 0.4 mm, with a droplet‑spacing of 20 mm, enabling droplet diameters ranging from 0.5 to 4.5 mm. The nozzle design should ensure that the water forms discrete droplets.

[Experiment Duration] Supports cyclical repetition; the duration of continuous rainfall is adjustable, with a maximum limit of 24 hours.

[Enhanced Rainfall Effect] The nozzle pressure must reach or exceed 276 kPa, with droplet diameters ranging from 2 to 4.5 mm. Nozzles will be mounted on the rear and top surfaces of the specimen holder, with each surface equipped with a grid‑type spray array consisting of two rows and two columns of nozzles. Similarly, the top surface will also feature a grid‑type spray array with two rows and two columns of nozzles. The spacing between nozzles is 500 × 500 mm; each nozzle delivers a full‑circle spray pattern, is detachable via threaded connections, and has an喷射 angle of approximately 60 degrees. The nozzle orifice diameter is 1.0 mm.

Military Standard Rain Test Chamber

Military Standard Rain Test – Design Drawing

[Sample Rotating Stage] The sample diameter is φ1000 mm; the load capacity is ≥100 kg; the rotational speed ranges from 1 to 16 rpm, continuously adjustable, with programmable automatic operation; the rotation angle and dwell time are both user‑settable.

Solution Value

The military‑standard rain‑exposure test chamber simulates real‑world rainfall conditions to evaluate a product’s water‑resistance performance. This solution meets the design requirements and features a simple structure, convenient operation, and high safety and reliability, ensuring that the product complies with military standards. Designed in strict accordance with military specifications, the chamber can replicate a wide range of harsh rain‑exposure scenarios, enabling comprehensive testing to verify compliance with military standards and enhancing the product’s reliability and stability. Moreover, the scheme emphasizes the standardization and formalization of the testing process, thereby improving the accuracy and credibility of the test results.

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