FIELD: development of ocean; thermal devices for motion of submersible vehicles in depth. SUBSTANCE: device makes use of difference in water temperatures in depth and on surface for varying the buoyancy. Volatile liquid is used as working medium which is in equilibrium with its vapor is space between walls of bellows of different diameters located on one axis so that bellows of lesser diameter is located inside bellows of large diameter. Common end surfaces of both bellows are hermetically closed. Both bellows are located inside pressure hull of submersible vehicle; one end surface of bellows rests against inner wall of submersible vehicle and opposite end surface is free to move. Space between smaller inner bellows is filled with oil and is communicated with reservoir by means of valve; this reservoir has elastic walls; it is located outside pressure hull of submersible vehicle. Tight pressure hull of submersible vehicle is filled with inert gas under pressure sufficient for forcing oil into outer reservoir at limiting depth. EFFECT: enhanced reliability and simplified construction. 1 dwg
