Negative pressure drainage device as a whole by a steel plate welded on both sides of the inlet pipe to install ventilation valves, positioning cage center guide, relying on the buoyancy block the inlet and then open the vent valve, the weight of water to fight the open valve to achieve water .

Negative-pressure auto drain, overall the steel plate welded to the sides of the water inlet valve and install ventilation with the fixed center guides, and rely on buoyancy Plug inlet to open the bleeder valve, water purification open the drain valve to drain water.

The negative pressure automatic water discharge bilge whole becomes by the steel plate welding, in which water inlet pipe both sides installment ventilation valve, with the adjusting clamp fixed center guide rod, depends upon the buoyancy to stop up the water inlet then to turn on the breather valve

Negative pressure automatic water consists of steel plates welded together as a whole, both sides of the inlet pipe installed ventilation valves, with position fixed Center bar, relying on buoyancy is blocked and thus opened the valve of intake, the weight of water open discharge valve to achieve re