Lubricating oil tank and rotary machine system

A lubricating oil tank, comprising:

• a tank casing extending in a first direction and configured to store lubricating oil therein;
• a plurality of introduction portions configured to introduce the lubricating oil into an inside of the tank casing and disposed separately from each other in the first direction;
• a discharge portion disposed at a first end portion of the tank casing in the first direction and configured to discharge the lubricating oil stored in the inside of the tank casing;
• a receiving portion disposed below the plurality of introduction portions in a vertical direction inside the tank casing and configured to receive the lubricating oil introduced from the plurality of introduction portions and cause the lubricating oil to flow toward a second end portion of the tank casing in the first direction;
• and
• a strainer configured to capture a foreign matter in the lubricating oil having flowed on the receiving portion, wherein
• the receiving portion is inclined downward in the vertical direction toward the second end portion in the first direction,
• the strainer is disposed at a position closer to the second end portion than the plurality of introduction portions in the first direction, and
• the tank casing includes a tank casing main body in which an opening configured to communicate between the inside and an outside of the tank casing is formed below an oil level of the lubricating oil stored inside the tank casing in the vertical direction and a lid portion attachable to and detachable from the tank casing main body and configured to close the opening.