To provide a vacuum breaker for preventing the rocking of a valve element which opens an annular valve seat.
A plug 2 is screwed to a body 1 which has an inflow port 5 and a second inflow port 6 connected to a fluid piping system and an air port 4 opened to air to form a valve casing. A valve chest 3 is formed in the valve casing in communication with the inflow port 5 and the second inflow port 6 and the air port 4. The annular valve seat 7 is provided between the air port 4 and the valve chest 3, and the valve element 8 for opening/closing the annular valve seat 7 is arranged in the valve chest 3 in the state of being energized against the annular valve seat 7 by a spring 9. Normally, the valve element 8 closes the annular valve seat 7, and when the inflow port 5 and the second inflow port 6 are in vacuum conditions, the valve element 8 opens the annular valve seat 7. The inner diameter of the valve chest 3 is formed somewhat larger than the outer diameter of the valve element 8 so that the outer periphery of the valve element 8 is guided to the axial direction of the annular valve seat 7 with the inner wall of the valve chest 3. The inflow port 5 is located on the side of the valve element 8 of the body 1, and the second inflow port 6 is located on the back of the valve element 8 of the body 1.
HIROYA MASAHISA
NISHIMURA SUKETAKA
