Abstract: A respiratory system provides bi-level pressure using a dual pressure device in fluid communication with a source of breathable gas and a patient interface. The dual pressure device includes a pipe submerged in a liquid in a container, and a float disposed along the pipe. The float cyclically moves up and down the pipe between a lower position and an upper position as the floats buoyancy changes. The floats position along the pipe causes the gas pressure level to alternate between a baseline pressure level and a peak pressure level by selectively blocking and unblocking an opening in the pipe, and selectively capturing and releasing gas from the float, with the maximum gas pressure being limited by the setting on a pressure relief valve.

Abstract: A respiratory system provides bi-level pressure using a dual pressure device in fluid communication with a source of breathable gas and a patient interface. The dual pressure device includes a pipe submerged in a liquid in a container, and a float disposed along the pipe. The float cyclically moves up and down the pipe between a lower position and an upper position as the floats buoyancy changes. The floats position along the pipe causes the gas pressure level to alternate between a baseline pressure level and a peak pressure level by selectively blocking and unblocking an opening in the pipe, and selectively capturing and releasing gas from the float, with the maximum gas pressure being limited by the setting on a pressure relief valve.