A combination includes a selectively driven fan and a bypass flow passage for bypassing the fan. The bypass flow passage communicates with a first check valve to allow air to flow from the bypass passage to a downstream location. A second check valve allows air driven by the fan to pass into a return passage and return to an inlet of the fan in the event that the discharge pressure from the fan overcomes a spring force associated with the second check valve. A heat exchanger pack and an environmental control system for use on an aircraft, and a method are all also disclosed.

A valve device is provided between a high-pressure pump and a fuel tank. A first valve member, an intermediate member and a second valve member are accommodated in a valve housing. The first valve member, which is arranged on a downstream side of the intermediate member, is biased by a first spring in a direction to a first valve seat formed in the intermediate member. The second valve member, which is arranged on an upstream side of the intermediate member, is biased by a second spring in a direction to a second valve seat formed in the intermediate member. When the first valve member is separated from the first valve seat, fuel flows in a forward direction from an upstream-side fuel passage to a downstream-side fuel passage. When the second valve member is separated from the second valve seat, the fuel flows in a reverse direction.

A valve device is provided between a high-pressure pump and a fuel tank. A first valve member, an intermediate member and a second valve member are accommodated in a valve housing. The first valve member, which is arranged on a downstream side of the intermediate member, is biased by a first spring in a direction to a first valve seat formed in the intermediate member. The second valve member, which is arranged on an upstream side of the intermediate member, is biased by a second spring in a direction to a second valve seat formed in the intermediate member. When the first valve member is separated from the first valve seat, fuel flows in a forward direction from an upstream-side fuel passage to a downstream-side fuel passage. When the second valve member is separated from the second valve seat, the fuel flows in a reverse direction.

A hydraulic valve includes a biasing member for generating a biasing force to press a valve seat and a valve member. When a second hydraulic chamber has higher hydraulic pressure than a first hydraulic chamber, a hydraulic pressure difference between the first and second hydraulic chambers acts on the valve seat to separate the valve seat from the valve member against the biasing force of the biasing member so that the first hydraulic chamber and the second hydraulic chamber come into fluidal communication.

A hydraulic valve includes a biasing member for generating a biasing force to press a valve seat and a valve member. When a second hydraulic chamber has higher hydraulic pressure than a first hydraulic chamber, a hydraulic pressure difference between the first and second hydraulic chambers acts on the valve seat to separate the valve seat from the valve member against the biasing force of the biasing member so that the first hydraulic chamber and the second hydraulic chamber come into fluidal communication.

A bi-directional valve with valve elements having compliant features biasing them together to maintain a sealing interface that defines a fluid communication barrier within the valve. Parting the valve elements from one another removes the sealing interface to allow fluid communication across the valve elements. The valve includes a side port and a choke member that selectively blocks fluid flow through the valve when moved adjacent the side port and selectively opens the valve to fluid communication when moved away from the side port. The choke member remains adjacent the side port until the valve elements are spaced a distance apart greater than that at which valve erosion or fluid cavitation occurs.

A vent having a vent housing defining a mounting structure, a first opening between a first end and a second end of the vent housing, a first airflow pathway from the first opening, a second airflow pathway from a second opening, and a draining pathway from the first airflow pathway through the first end of the vent housing. The first airflow pathway has a first segment and a second segment extending in opposite axial directions. An inlet relief valve and an outlet relief valve are arranged in parallel between the first and second airflow pathways. The inlet relief valve opens upon exceeding a first threshold pressure differential of the second relative to the first airflow pathway. The outlet relief valve opens upon exceeding a second pressure differential of the first relative to the second airflow pathway. A filter assembly is disposed in the vent housing across the second airflow pathway.

A vent having a vent housing defining a mounting structure, a first opening between a first end and a second end of the vent housing, a first airflow pathway from the first opening, a second airflow pathway from a second opening, and a draining pathway from the first airflow pathway through the first end of the vent housing. The first airflow pathway has a first segment and a second segment extending in opposite axial directions. An inlet relief valve and an outlet relief valve are arranged in parallel between the first and second airflow pathways. The inlet relief valve opens upon exceeding a first threshold pressure differential of the second relative to the first airflow pathway. The outlet relief valve opens upon exceeding a second pressure differential of the first relative to the second airflow pathway. A filter assembly is disposed in the vent housing across the second airflow pathway.

A diaphragm valve has a valve body which includes at least one flow passage for fluid flow, a valve drive including a housing, and a diaphragm which can be deflected by the valve drive, in order to selectively open and close the flow passage. The rim of the diaphragm is axially clamped in a fluid-tight way between valve body and valve drive, wherein clamping of the diaphragm is effected by a screw-nut connection and the screw and the nut surround the rim of the diaphragm as seen in actuating direction of the valve drive and one of the two parts formed by screw and nut is non-rotatably provided at the valve body or at the valve drive. The other one of the two parts can be screwed in or on and additionally is rotatorily movable. The movable part is supported on the valve drive or on the valve body by an anti-friction bearing.

A diaphragm valve has a valve body which includes at least one flow passage for fluid flow, a valve drive including a housing, and a diaphragm which can be deflected by the valve drive, in order to selectively open and close the flow passage. The rim of the diaphragm is axially clamped in a fluid-tight way between valve body and valve drive, wherein clamping of the diaphragm is effected by a screw-nut connection and the screw and the nut surround the rim of the diaphragm as seen in actuating direction of the valve drive and one of the two parts formed by screw and nut is non-rotatably provided at the valve body or at the valve drive. The other one of the two parts can be screwed in or on and additionally is rotatorily movable. The movable part is supported on the valve drive or on the valve body by an anti-friction bearing.