Normally closed in-channel micro check valve

摘要

In an embodiment, a check valve assembly may include an in-channel check valve connected between the front and rear portions of a channel attached to a silicon substrate. The channel may have a width between about 10 mum and about 400 mum, and the check valve may have a width between about 50 mum and about 500 mum. The check valve may be generally circular in shape. The check valve may also be normally closed, that is, sealed in the absence of a pressure differential between the front and rear portions of the channel. The check valve may include a sealing cap that contacts a valve seat to seal the valve. The sealing cap and the valve seat may each be formed from Parylene C membranes that are about 1 mum to about 5 mum thick. The valve seat may include a metal layer to separate the contacting surfaces of the valve seat and the sealing cap in the closed position. The check valve may open for forward pressures that match or exceed a threshold pressure and remain closed for forward pressures below the threshold pressure and reverse pressures.