Features to drive fluid toward an ultrasonic blade of a surgical instrument

An apparatus for operating on tissue, the apparatus comprising:

• (a) a body;
• (b) a shaft assembly extending distally from the body;
• (c) an end effector, wherein the end effector comprises:
• an ultrasonic blade, and
• (ii) a clamp arm, wherein the clamp arm is movable toward and away from the ultrasonic blade to clamp tissue therebetween;
• and
• (d) a blade cooling system operable to deliver coolant to the ultrasonic blade,
• wherein the blade cooling system comprises a reservoir arranged within a distal portion of the shaft assembly and configured to store coolant,
• wherein the reservoir is configured to direct coolant to the ultrasonic blade in response to movement of the clamp arm relative to the ultrasonic blade.

An apparatus for operating on tissue, the apparatus comprising:

• (a) a body;
• (b) a shaft assembly extending distally from the body;
• (c) an end effector, wherein the end effector comprises:
• an ultrasonic blade, and
• (ii) a clamp arm, wherein the clamp arm is movable toward and away from the ultrasonic blade to clamp tissue therebetween;
• and
• (d) a blade cooling system operable to deliver coolant to the ultrasonic blade,
• wherein the blade cooling system comprises an outlet opening provided by the clamp arm, an inlet opening provided by the clamp arm and arranged distally of the outlet opening, and an interior chamber of the clamp arm, wherein the interior chamber is configured to receive evaporated fluid through the inlet opening when the clamp arm is moved toward the ultrasonic blade, wherein the interior chamber is further configured to condense the evaporated fluid into liquid and direct the liquid through the outlet opening toward the ultrasonic blade to thereby cool the ultrasonic blade when the clamp arm is moved away from the ultrasonic blade.