The present invention relates to respirators or ventilators in general, and particularly to exhalation valve assemblies therefor.
A ventilated patient who is attached to respirator for assited breathing typically inhales and exhales via separate tubes that merge into Y-connector near the patient. Valves in the inhalation and exhalation tubes open and close at appropriate times to regulate the breathing cycle, with the exhalation valve in the exhalation tube being allowed to open as the patient exhales, while the inhalation valve is simultaneously closed to prevent flow of exhaled gas into the inhalation tube.
Respirator exhalation valves typically include a flexible diaphragm mounted in a valve assembly having an inlet port, an outlet port and a control pressure port. During patient inhalation, the diaphragm rests on a valve seat and prevents gas in the exhalation tube from circulating back towards the patient via the inlet port, while during exhalation the diaphragm lifts from the valve seat and allows exhaled gas to flow from inlet port through the outlet port. The pressure control port allows a control pressure to be applied to the diaphragm from above, ensuring that the diaphragm remains firmly seated during inhalation. The control pressure is typically sufficiently reduced during exhalation to allow the diaphragm to be unseated by patient expiration pressure.
Should the outlet port become blocked, lung over-pressurization may occur, leading to patient injury or death. An exhalation valve assembly that prevents outlet port blockage would therefore be advantageous.
In accordance with a preferred embodiment of the present invention, an exhalation valve assembly is provided with an improved outlet port that prevents blockage thereof.
The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the appended drawings in which:
Reference is now made to
Reference is now made to
When control pressure is applied to chamber 212 above the diaphragm exceeds the pressure in inlet port 202, diaphragm 210 is held against valve seat 214, preventing exhalation flow from inlet port 202 to outlet port 204. When the control pressure is removed or sufficiently reduced, diaphragm 210 may be lifted from valve seat 214 by patient expiration pressure, allowing exhalation flow.
To prevent blockage of outlet port 204 during patient exhalation, port 204 preferably includes an outlet lip 220 that is not uniformly flat in any cutting plane. For example, outlet lip 220 may be crenelated, as may be seen in greater detail in
While the present invention has been described with reference to one or more specific embodiments, the description is intended to be illustrative of the invention as a whole and is not to be construed as limiting the invention to the embodiments shown. It is appreciated that various modifications may occur to those skilled in the art that, while not specifically shown herein, are nevertheless within the true spirit and scope of the invention.