A ventilator device and system comprising a rotating compressor, preferably a drag compressor, which, at the beginning of each inspiratory ventilation phase, is accelerated to a sufficient speed to deliver the desired inspiratory gas flow, and is subsequently stopped or decelerated to a basal flow level to permit the expiratory ventilation phase to occur. The ventilator device is small and light weight enough to be utilized in portable applications. The ventilator device is power efficient enough to operate for extended periods of time on internal or external batteries. Also provided is an oxygen blending apparatus which utilizes solenoid valves having specific orifice sizes for blending desired amounts of oxygen into the inspiratory gas flow. Also provided is an exhalation valve having an exhalation flow transducer which incorporates a radio frequency data base to provide an attendant controller with specific calibration information for the exhalation flow transducer.

Portable drag compressor powered mechanical ventilator

An apparatus (10) for detecting fluid flow by obtaining a differential pressure across an obstruction (13) in a fluid conveying channel (18). The obstruction (13) is hingably connected to the housing (4) of the channel (18). The connection is of a width substantially less than the periphery of the channel (18) so as to reduce the collection of contaminants which decrease the accuracy of the apparatus. Because the orifice defined by the area between the obstruction (13) and the periphery of the channel (18) is variable according to the fluid flow, the pressure differential versus flowrate relationship is different from the square-law relationship of a fixed orifice, and provides a relatively high pressure differential at low flowrates and a relatively low pressure differential at high flowrates.

Variable Orifice flow sensing apparatus

An apparatus for controllably actuating a hydraulic actuator is provided. The apparatus is connected between a source of pressurized hydraulic fluid and the hydraulic actuator. The apparatus controllably provides pressurized hydraulic fluid to the hydraulic actuator. The apparatus includes a controller for receiving an operating signal and a load pressure signal and responsively actuating the hydraulic actuator.

Hydraulic control apparatus

Disclosed is a bi-directional differential pressure flow sensor that is configured to establish a direction and flow rate of a fluid flow The flow sensor includes a flow restriction member, a differential pressure sensor, and processing electronics The flow restriction member is configured to produce a pressure drop when placed inline with the fluid flow The differential pressure sensor is embedded or integral with the flow restriction member and produces a differential pressure signal that is indicative of the pressure drop The processing electronics produces a flow rate signal that is indicative of the direction and flow rate of the fluid flow as a function of the differential pressure signal

Bi-directional differential pressure flow sensor

A hydraulic circuit, particularly any for an automated twin clutch transmission for motor vehicles, including a countershaft with two parallel power transmission branches, two clutches, a high pressure circuit having at least one actuator for the countershaft transmission and/or the clutches, a low pressure circuit for lubrication and/or cooling of elements of the twin clutch transmission, and a first adjustment pump for the high pressure circuit. The low pressure circuit includes a plurality of secondary pumps which are connected in parallel to the first adjustment pump.

Hydraulic circuit for an automated twin clutch transmission for motor vehicles

A device for controlling a hydraulic actuator comprises two servo loops having in common a fluid pressure operated main valve and an electrically operated pilot valve for controlling the main valve. One of the servo loops is for flow control and contains a flow transducer for producing an electrical feedback signal responsively to fluid flow to the actuator and a comparator for comparing the flow feedback signal with a first electrical input signal. The other servo loop is for force control and contains pressure transducing means for producing an electrical feedback signal responsively to the pressure drop across the actuator and a second comparator for comparing the force feedback signal with a second electrical input signal.

Hydraulic actuator controls

A rotary, variable-displacement hydraulic pump (1) in use driven by a prime mover (4), the pump (1) compris­ing control means (5) for varying the displacement of the pump and means (17) responsive to a signal related to the rotational speed of the pump and operable to override the control means so as, in use, to prevent stalling of the prime mover (4) within a predetermined operational range of the prime mover.

Peter Michael Hamey

Papers

Hydraulic actuator controls

Variable displacement pumps