US 11,746,509 B2
Backflow prevention device
Kenny Bassett, Columbia, MO (US); and Delvin Mellerup, Clark, MO (US)
Filed by Kenny Bassett, Columbia, MO (US); and Delvin Mellerup, Clark, MO (US)
Filed on Sep. 1, 2021, as Appl. No. 17/464,342.
Prior Publication US 2023/0065329 A1, Mar. 2, 2023
Int. Cl. E03B 7/07 (2006.01); F16K 27/02 (2006.01); F16K 15/04 (2006.01)
CPC E03B 7/077 (2013.01) [F16K 15/044 (2013.01); F16K 27/0209 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A backflow prevention device comprising:
a device body having an inlet end portion and an outlet end portion opposite the inlet end portion, the outlet end portion spaced apart from the inlet end portion along an axis, the inlet end portion defining an inlet port, the outlet end portion defining an outlet port, the device body defining a device passage connecting the inlet port to the outlet port;
a piston received in the device passage between the inlet port and the outlet port, the piston comprising a piston member having an upstream end surface and a downstream end surface spaced apart along the axis;
wherein the device passage comprises a middle segment between the piston and the outlet port and the device body defines a relief port configured for fluid communication with the middle segment of the device passage,
wherein the piston is movable between a normal flow position in which the piston blocks fluid communication between the relief port and the middle segment of the device passage and a backflow position in which the piston allows fluid communication between the relief port and the middle segment of the device passage, the piston being configured to move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port;
wherein the relief port opposes the downstream end surface of the piston member such that atmospheric pressure acts on the downstream end surface of the piston member through the relief port.