Cooling device for ship propulsion machine

A cooling device for a ship propulsion machine, the cooling device being provided in a ship propulsion machine, taking water of an outside of the ship propulsion machine into the ship propulsion machine, cooling a power source of the ship propulsion machine by flowing the taken water around or inside the power source as cooling water, and discharging the cooling water after flowing around or inside the power source to the outside of the ship propulsion machine, the cooling device comprising:

• a drain passage configured to discharge the cooling water after flowing around or inside the power source to the outside of the ship propulsion machine;
• a collection passage provided between an upstream portion and a downstream portion of the drain passage and connecting the upstream portion and the downstream portion of the drain passage;
• a collector provided in a middle of the collection passage and configured to collect fine objects contained in the cooling water flowing through the collection passage from the upstream portion of the drain passage toward the downstream portion of the drain passage;
• a bypass passage provided in parallel with the collection passage between the upstream portion and the downstream portion of the drain passage and connecting the upstream portion and the downstream portion of the drain passage;
• a branched portion where the upstream portion of the drain passage branches into the collection passage and the bypass passage;
• and
• a confluence portion where the collection passage and the bypass passage join the downstream portion of the drain passage, wherein
• the upstream portion of the drain passage, the collection passage, and the bypass passage are arranged such that a difference between a flowing direction of the cooling water flowing from the upstream portion of the drain passage into the branched portion and a flowing direction of the cooling water flowing from the branched portion into the collection passage is smaller than a difference between the flowing direction of the cooling water flowing from the upstream portion of the drain passage into the branched portion and a flowing direction of the cooling water flowing from the branched portion into the bypass passage, and
• the downstream portion of the drain passage, the collection passage, and the bypass passage are arranged such that a difference between a flowing direction of the cooling water flowing from the bypass passage into the confluence portion and a flowing direction of the cooling water flowing from the confluence portion into the downstream portion of the drain passage is smaller than a difference between a flowing direction of the cooling water flowing from the collection passage into the confluence portion and a flowing direction of the cooling water flowing from the confluence portion into the downstream portion of the drain passage.