Process-chamber flow control system

A device for regulating the flow of fluid from an environment to an evacuation means, the device comprising:

• an output in communication with the evacuation means;
• a barrier mounted across and spaced away from the output so as to form an evacuation port between the barrier and the output;
• a piston having an aperture disposed therein and being movably mounted proximate to the output such that fluid flowing into the output passes through the aperture and so as to variably impede fluid flowing to the evacuation means, the piston having a distal face, exposed to a reference pressure that is equal to the pressure from the environment, and a frontal face, exposed to fluid upstream from the aperture, such that an increase in pressure on the distal face of the piston tends to increase the piston's impedance on the fluid flow, and an increase in pressure on the frontal face of the piston tends to lessen the piston's impedance on the fluid flow;
• wherein the aperture and the output are concentrically aligned through a midpoint on the frontal face of the piston;
• and
• restoring means for exerting a force on the piston so as to tend to lessen the piston's impedance on the fluid flow.

A device for regulating the flow of fluid from an environment to an evacuation means, the device comprising:

• an output in communication with the evacuation means;
• a piston being movably mounted proximate to the output so as to variably impede fluid flowing to the evacuation means, the piston having an aperture concentrically aligned with the output irrespective of the movement of the piston such that fluid flowing into the output passes through the aperture, a distal face exposed to a reference pressure that is equal to the pressure in the environment, and a frontal face exposed to fluid upstream from the aperture such that an increase in pressure on the distal face of the piston tends to increase the piston's impedance on the fluid flow, and an increase in pressure on the frontal face of the piston tends to lessen the piston's impedance on the fluid flow;
• and
• restoring means for exerting a force on the piston so as to tend to lessen the piston's impedance on the fluid flow.

A device for regulating the flow of fluid from an environment to an evacuation means, the device comprising:

• an output in communication with the evacuation means;
• a piston having an aperture disposed therein and being movably mounted proximate to the output so as to variably impede fluid flowing to the evacuation means, wherein fluid flowing into the output passes through the aperture in a direction parallel to the movement of the piston, the piston having a distal face, exposed to a reference pressure that is equal to the pressure in the environment, and a frontal face, exposed to fluid upstream from the aperture, such that an increase in pressure on the distal face of the piston tends to increase the piston's impedance on the fluid flow, and an increase in pressure on the frontal face of the piston tends to lessen the piston's impedance on the fluid flow;
• and
• restoring means for exerting a force on the piston so as to tend to lessen the piston's impedance on the fluid flow.

A device for regulating the flow of fluid from an environment to an evacuation means, the device comprising:

• an output in communication with the evacuation means;
• a piston being movably mounted proximate to the output so as to variably impede fluid flowing to the evacuation means, the piston having an aperture concentrically aligned with the output irrespective of the movement of the piston such that fluid flowing into the output passes through the aperture, a distal face exposed to a reference pressure, and a frontal face exposed to fluid upstream from the aperture such that an increase in pressure on the distal face of the piston tends to increase the piston's impedance on the fluid flow, and an increase in pressure on the frontal face of the piston tends to lessen the piston's impedance on the fluid flow;
• means for preventing fluid communication between the distal face and the frontal face;
• restoring means for exerting a force on the piston so as to tend to lessen the piston's impedance on the fluid flow;
• and
• a barrier mounted across and spaced away from the output so as to form an evacuation port between the barrier and the output that may be partially occluded as the piston moves.

A device for regulating the flow of fluid from an environment to an evacuation means, the device comprising:

• an output in communication with the evacuation means;
• a piston having an aperture disposed therein and being movably mounted proximate to the output so as to variably impede fluid flowing to the evacuation means, wherein fluid flowing into the output passes through the aperture in a direction parallel to the movement of the piston, the piston having a distal face, exposed to a reference pressure, and a frontal face, exposed to fluid upstream from the aperture, such that an increase in pressure on the distal face of the piston tends to increase the piston's impedance on the fluid flow, and an increase in pressure on the frontal face of the piston tends to lessen the piston's impedance on the fluid flow;
• means for preventing fluid communication between the distal face and the frontal face;
• restoring means for exerting a force on the piston so as to tend to lessen the piston's impedance on the fluid flow;
• and
• a barrier mounted across and spaced away from the output so as to form an evacuation port between the barrier and the output that may be partially occluded as the piston moves.