Patent ID: 9664296
Date: 2017-05-30
CPC Classifications: F04B,F16K

Claim:
1. A check valve for connecting to equipment supplied with a liquid, comprising: a valve body extending along an axis; an inlet passage within the valve body having an inlet cavity for entry of liquid into the valve; an inlet valve to allow fluid passage from the inlet cavity to the inlet passage; an outlet passage within the valve body having an outlet for exit of liquid from the valve; an intermediate passage in communication with the inlet passage through a connecting passage and the outlet passage, the inlet valve, inlet passage, outlet passage, and intermediate passages being parallel to the valve body axis; an internal valve within the valve body located between the inlet valve and the outlet passage and parallel to the valve body axis, the internal valve allowing the flow of liquid through the valve body under pressure from the inlet passage in a first direction, through the intermediate passage in a second direction opposite to the first direction, and through the outlet passage in the first direction but preventing the backflow of material from the outlet through the valve body; and wherein liquid is trapped within the inlet passage, the connecting passage, and the intermediate passage when pressure required to open the inlet valve and the internal valves is reduced to stop liquid flow.