Patent ID: 6298870
Filing Date: 2001-10-09
Classification: E03F,Y10T

Abstract:
A vacuum-operated sewage system for transporting sewage in the form of a two-phase air/liquid flow comprising air and sewage which flows through a vacuum sewage pipe evacuated inside to a vacuum state,wherein a first air inlet valve is disposed in the neighbourhood of and upstream of a potential water-block formation area in the vacuum sewage pipe so as to supply air from above the ground to the area, and the first air inlet valve is allowed to open when a degree of vacuum drops in the vacuum sewage pipe; andwherein a second air inlet valve is connected to the first air inlet valve and subjected to a pressure inside the vacuum sewage pipe transmitted through the first air inlet valve in an open state, and the second air inlet valve is allowed to open when a degree of vacuum drops in the vacuum sewage pipe thereby to supply air thereto via the first air inlet valve, and allowed to close when the degree of vacuum in the vacuum sewage pipe drops as far as a predetermined degree.