Every suction collection circuit must use a suction canister to prevent fluids from entering the regulator and central suction system. These canisters will employ a shutoff mechanism to avoid overflow. Either by human error or manufacturing defects, the shutoff mechanisms can fail and flood the suction regulator and central suction system. A trap bottle prevents gross fluid infiltration into the regulator. Since trap bottles are not a bacterial barrier, the notion that they are needed to avoid contamination from entering your central suction system is likewise an urban myth.