A battery retaining system for a portable oxygen concentrator includes a first rail configured to receive a first slide of a battery, a second rail configured to receive a second slide of the battery, the second rail being spaced apart from the first rail so as to form a channel configured to receive the battery, and a flexible stiffening mechanism configured to impart a biasing force on a surface of the battery when the battery is received within the channel. The flexible stiffening mechanism includes a protrusion projecting from the first rail at least partially towards the second rail and a slit positioned behind the protrusion and configured to facilitate travel of the protrusion fore and aft.

A high and low-pressure integrated air pump includes a single housing including an air inlet and an air outlet. A high-pressure pump is disposed within the housing and in fluid communication with the air inlet, and uses a first outlet passage to discharge to the air outlet. A low-pressure pump is also disposed within the housing and in fluid communication with the air inlet, and uses a second outlet passage to discharge to the air outlet.

A method of a control system (2200) controls an inductance motor in a blower including an impeller and volute using a pressure compensation control system. The control system may be implemented in a respiratory pressure therapy device. The control system may include a sensor configured to provide a pressure signal indicative of the pressure of a flow of fluid produced by the blower. A measured pressure may be compared to a set pressure to determine a pressure error. A slip frequency may be adjusted as a function of the pressure error in an attempt to eliminate or minimise the pressure error.

A rotary machine system includes: a rotary machine including a gas seal portion; a gas seal device connected to the rotary machine and that supplies a seal gas to the gas seal portion; a pressure sensor that detects a pressure of the seal gas; a vent portion that discharges the seal gas discharged from the gas seal portion; and a vent pressure sensor that detects a pressure in the vent portion. The rotary machine includes: a casing through which a working fluid flows; a rotatable rotary shaft that passes; and the gas seal portion provided between the casing and the rotary shaft and that seals the working fluid by the seal gas having a pressure higher than a pressure of the working fluid in the casing. The gas seal device includes: a pressure regulating valve; and a control part that controls the pressure regulating valve.

A fan module includes a first casing, a driving motor disposed in the first casing, a first rotor connected to the first driving motor, a second casing, a second rotor pivotally configured in the second casing, at least one guiding member and a shift apparatus connected to the first casing and the second casing, the first rotor includes a first rotating shaft and a plurality of first blades, the second rotor includes a second rotating shaft and a plurality of second blades, the guiding member is disposed on the first blade and the second blade. The whole height of the blade is adjusted by adjusting the distance between the two group blades, then the efficiency of the fan is improved effectively to optimize the noise level and the air flow.

A fan assembly is provided. The fan assembly includes a fan, a fan casing circumscribing the fan, and a fan casing heating system in thermal communication with the fan casing. The fan includes a hub, and a plurality of fan blades extending from the hub. Each fan blade of the plurality of fan blades terminates at a respective blade tip. A clearance gap is defined between the fan casing and the blade tips. The fan casing heating system is configured to apply heat to the fan casing when the fan is operating in a first operational mode, and remove the applied heat when the fan transitions into a second operational mode.

A gas turbine engine includes a main engine compressor section. A booster compressor changing a pressure of airflow received from the main engine compressor section to a pressure desired for a pneumatic system. The booster compressor operates at airflow conditions greater than a demand by the pneumatic system. A speed change system driving the booster compressor at speeds corresponding to a demand of the pneumatic system. A bleed air system for a gas turbine engine and a method of controlling engine bleed airflow are also disclosed.

A gas turbine engine includes a main engine compressor section. A booster compressor changes a pressure of airflow received from the main engine compressor section to a pressure desired for a pneumatic system. The booster compressor is configured to operate at airflow conditions greater than a demand of the pneumatic system. An exhaust valve controls airflow between an exhaust outlet and an outlet passage to the pneumatic system. The exhaust valve is operable to exhaust airflow from the booster compressor in excess of the demand of the pneumatic system. A bleed air system for a gas turbine engine and a method of controlling engine bleed airflow are also disclosed.

An air filtration system is described that is suited for CBRN and ColPro applications, and has an integrated inertial particle separator (IPS) and scavenge fan blower as a pre-dust/particle filter, a variable speed fan blower, and a filter housing that mounts two gas-particulate filter sets. The variable speed fan blower, managed by a motor control unit and motor speed algorithm, automatically adjusts its speed to maintain constant air flow regardless of its altitude.

A long-distance speed control system for a brushless DC motor of a fan is provided. The long-distance speed control system includes a switch connected with a mains power supply, a switch circuit, a voltage detection module, a power cord, a processing unit, and a drive unit, which can control the multi-stage rotational speed of the motor. In the field of brushless DC motors for fans, there is no need to use analog-to-digital conversion chips between the mains power supply and the processor, having the advantages of low cost, environmental protection, and reduction of waste of earth resources. Besides, the switch, the switch circuit and the power cord can withstand the mains power supply, having the advantages of less signal attenuation and long-distance transmission.