Wuhan Mobile Toilet Installation
The installation of mobile toilets in Wuhan requires a comprehensive approach encompassing design, material selection, connection, system control, environmental adaptation, and process validation. The specific key points are as follows:
Sewage System Design
It is necessary to balance the "siphon effect" and "gravity flow", with the inclination angle of the sewage storage tank controlled within 3-5 degrees to ensure the separation of solids and liquids, prevent blockages, and reduce odor diffusion. The layout of ventilation openings is based on Bernoulli's equation, achieving directional exhaust through negative pressure to prevent odor overflow.
Material Selection
The outer shell material must meet the dual requirements of low thermal conductivity and UV resistance. High-density polyethylene (HDPE) has a low thermal conductivity (approximately 0.4 W/m·K), reducing internal temperature fluctuations, and its molecular structure resists UV degradation, preventing shell embrittlement. Although fiberglass has higher strength, its large coefficient of thermal expansion (approximately 30×10⁻⁶/°C) can lead to joint cracking and higher maintenance costs, making HDPE more commonly used.
Modular Connection and Mechanical Stability
The toilet unit is fixed using a combination of mortise-and-tenon-style clamps and bolts, utilizing the principle of static friction to prevent tipping. The bottom is equipped with adjustable feet (height range 10-30 cm) to adapt to uneven ground surfaces, and the overall center of gravity is kept below the support surface by adjusting bolt torque (80-120 N·m) to avoid tipping risks.
Fluid Control in Water Supply and Drainage Systems
The volume ratio of the freshwater tank to the sewage tank is typically 1:3, designed based on a cumulative probability model. Pipeline connections use quick-connect fittings, with internal O-ring seals (made of nitrile rubber) achieving zero leakage through 15-20% compression deformation. The sewage discharge valve adopts a lever-type structure with a mechanical arm ratio of 1:4, reducing manual operating force.
Environmental Adaptability
- Summer: The outer shell is coated with a reflective coating containing titanium dioxide (refractive index 2.7), reflecting over 70% of infrared radiation. Internally, paraffin-based phase change materials (melting point 28-30°C) are installed to control temperature variations within ±5°C.
- Winter: Electric heating films are used for auxiliary insulation, with a power density of approximately 200 watts per square meter, ensuring the internal temperature does not fall below 5°C to prevent water pipe freezing.
Installation Process
The installation process is divided into three stages: mechanical verification, seal testing, and fluid calibration:
- Mechanical Verification: Use an inclinometer to measure the ground slope (allowable deviation ≤ 2°), adjust with shims if necessary, and then tighten the bolts with a torque wrench.
- Seal Testing: Conduct airtight or watertight tests on pipeline connections, sewage storage tanks, and other parts to ensure no leakage.
- Fluid Calibration: Adjust the flow ratio between the freshwater tank and the sewage tank, and verify whether the operating force of the discharge valve meets the design standards.
