Patent ID: 7578931

Claim:
A pressure release device for a ground cleaning vehicle having a wastewater tank with an air suction pipe and an airtight cover, the pressure release device comprising: an air relief valve, a spring, a filter screen, a filter screen holder having a central hole, a crown bar, a floating ball, and a foam isolating bucket; wherein said filter screen holder is fixedly connected to an upper wall of the wastewater tank, and said filter screen is fixedly connected to said filter screen holder; said foam isolating bucket is connected to said filter screen holder and is located inside of the wastewater tank; said floating ball is disposed inside of said foam isolating bucket and is connected to said crown bar; said crown bar is installed in said central hole of the filter screen holder, and can slide up and down with the floating of the floating ball; said air relief valve is actuated by said crown bar within said central hole of said filter screen holder; said filter screen is connected to said upper wall of said wastewater tank and fits tightly around said foam isolating bucket; said airtight cover serves to cover the top of the wastewater tank and is located on top of the filter screen holder, and comprises a cover shell and a central hole, wherein a seal groove for accommodating a seal gasket is formed on the cover shell; said air relief valve comprises a handle part and a tubular shank part, wherein the shank part is installed into the central hole of the airtight cover, a circular groove for housing a spring cushion is formed at the lower portion of the shank part; and said spring is fit installed around the outer wall of the central hole of the airtight cover, wherein the two ends of the spring are contacted with the spring cushion and the inner wall surface of the cover shell of the airtight cover, respectively.