Abstract: An electronically controlled back pressure regulator comprises an analysis device having a vent coupled to the analysis device through a vent path, a pressure sensor coupled to the vent path, a proportional valve coupled to the vent path, the proportional valve configured to controllably alter pressure in the analysis device, and an electronically controlled closed-loop controller configured to control a flow through the vent based on a signal from the pressure sensor and an electronically controlled pressure setpoint.

Abstract: An electro-mechanical variable fluid flow restrictor includes a support having a passage and a seal surface, a deformable seal that is engageable with the seal surface, and a bias member for exerting an electronically controlled variable bias against the deformable seal. The seal surface includes channels formed in its surface that extend beneath the deformable seal. The bias member can exert a bias sufficient to cause the deformable seal to fill the channels, preventing fluid flow through the channels. When the bias member decreases the bias against the deformable seal, the deformable seal gradually moves out of the channels, allowing fluid flow through the channels, and through the passage in a flow control. The deformable seal does not need to separate from the seal surface to allow fluid flow. Instead, fluid flows through the small, controlled flow areas created when the deformable seal withdraws from the channels.