Abstract: A mechanical shutdown valve for preventing an over pressure condition is described. A valve body has an inlet, an outlet, and a channel extending from the inlet to the outlet. A valve seat and a diaphragm are positioned in the valve body. The diaphragm controls a fluid flow through the valve body. A mesh is coupled to the diaphragm such that the mesh and the diaphragm separate an upstream portion of the channel from a downstream portion of the channel. The mesh extends from the diaphragm to an inner surface of the valve body and limits fluid flow between the diaphragm and the valve body. A spring biases the diaphragm towards the open position. A characteristic of the spring determines a differential pressure threshold between the upstream portion of the channel and a downstream portion of the channel at which the diaphragm engages the valve seat.

Abstract: A membrane system includes a first membrane and a second membrane. At a given temperature and pressure: the first membrane has a permeation rate for a first gas and a selectivity for a gas mixture comprising the first gas a second gas different from the first gas; the second membrane has a permeation rate for the first gas and a selectivity for the gas mixture; the permeation rate of the first membrane is greater than the permeation rate of the second membrane; and the selectivity of the second membrane is greater than the selectivity of the first membrane.

Abstract: A mechanical shutdown valve for preventing an over pressure condition is described. A valve body has an inlet, an outlet, and a channel extending from the inlet to the outlet. A valve seat and a diaphragm are positioned in the valve body. The diaphragm controls a fluid flow through the valve body. A mesh is coupled to the diaphragm such that the mesh and the diaphragm separate an upstream portion of the channel from a downstream portion of the channel. The mesh extends from the diaphragm to an inner surface of the valve body and limits fluid flow between the diaphragm and the valve body. A spring biases the diaphragm towards the open position. A characteristic of the spring determines a differential pressure threshold between the upstream portion of the channel and a downstream portion of the channel at which the diaphragm engages the valve seat.

Abstract: A mechanical shutdown valve for preventing an over pressure condition is described. A valve body has an inlet, an outlet, and a channel extending from the inlet to the outlet. A valve seat and a diaphragm are positioned in the valve body. The diaphragm controls a fluid flow through the valve body. A mesh is coupled to the diaphragm such that the mesh and the diaphragm separate an upstream portion of the channel from a downstream portion of the channel. The mesh extends from the diaphragm to an inner surface of the valve body and limits fluid flow between the diaphragm and the valve body. A spring biases the diaphragm towards the open position. A characteristic of the spring determines a differential pressure threshold between the upstream portion of the channel and a downstream portion of the channel at which the diaphragm engages the valve seat.

Abstract: A mechanical shutdown valve for preventing an over pressure condition is described. A valve body has an inlet, an outlet, and a channel extending from the inlet to the outlet. A valve seat and a diaphragm are positioned in the valve body. The diaphragm controls a fluid flow through the valve body. A mesh is coupled to the diaphragm such that the mesh and the diaphragm separate an upstream portion of the channel from a downstream portion of the channel. The mesh extends from the diaphragm to an inner surface of the valve body and limits fluid flow between the diaphragm and the valve body. A spring biases the diaphragm towards the open position. A characteristic of the spring determines a differential pressure threshold between the upstream portion of the channel and a downstream portion of the channel at which the diaphragm engages the valve seat.