A fluid level indicator (50) for indicating the fluid level in an ophthalmic irrigation and/or aspiration system comprises a chamber (10) configured for holding a surgical fluid (F). The chamber (10) comprises at least one fluid port (72; 74) and a pressure port (71) for connection to a pressure source (20). A channel (140) extends from the chamber (10). The fluid level indicator (50) comprises a float (160) having a float body (162) disposed within the chamber (10) and a stem (164) extending from the float body (160) into the channel (10). The float body (160) is configured to move with the level of fluid within the chamber (10), thereby moving the stem (164) along the channel (140) extending from the chamber (10). The position of the stem (164) within the channel (40) indicates the fluid level within the chamber (10).

A fluid level indicator (50) for indicating the fluid level in an ophthalmic irrigation and/or aspiration system comprises a chamber (10) configured for holding a surgical fluid (F). The chamber (10) comprises at least one fluid port (72; 74) and a pressure port (71) for connection to a pressure source (20). A channel (140) extends from the chamber (10). The fluid level indicator (50) comprises a float (160) having a float body (162) disposed within the chamber (10) and a stem (164) extending from the float body (160) into the channel (10). The float body (160) is configured to move with the level of fluid within the chamber (10), thereby moving the stem (164) along the channel (140) extending from the chamber (10). The position of the stem (164) within the channel (40) indicates the fluid level within the chamber (10).

An overflow blocking apparatus for a tank lorry comprises: a main body (10) having a first cylinder (11) and a second cylinder (12) formed therein, a first air supply passage (13) connected to a side of the first cylinder, and a first air discharge passage (15) formed at one side; a piston (20) having one end connected to a rod (21) and the other end elastically supported with a spring (22); a lower main body (30) connected to the main body and having a lot hole (31) therein and a second air supply passage (32) and a second air discharge passage (33) connected to the wall of the lot hole; a lot (40) capable of reciprocating in the lot hole; a tube (50) provided in the form of wrapping the outer side of the lower main body; and a float (60) provided to be lifted by buoyancy of oil.