GB1215633A - Appliance for alternately filling and emptying an enclosure - Google Patents

Abstract

1,215,633. 633. Pure fluid oscillators. BERTIN ET COMPAGNIE. March 21, 1968 [March 21, 1967], No. 13808/68. Heading G3H. [Also in Division A5 and F1] A respirator incorporates a fluid switching device for alternately pressurizing and evacuating a passage 20 connected to the patient's lungs, a deformable chamber 25 being incorporated to determine the length of the pressurizing and evacuating periods. In the embodiment shown, a main respirator comprises a nozzle 14 which directs an air jet into a substantially coaxial exhaust passage 18, or passage 20 leading to the patient via a mask, according to the control pressures in control ducts 23, 24. The main respirator is controlled by a smaller, pilot respirator, in which nozzle 13 directs an air jet towards exhaust passage 17 or a passage 19 connected to chamber 25, a feedback passage 27 and control duct 23. In operation with valves 32 and 33 open, and valve 29 closed the air jet from nozzle 13 initially flows through exhaust passage 17 and includes flow from passage 19, thereby reducing the pressure in chamber 25 the reduced pressure acts through passage 31 and control duct 23 to switch the air jet from nozzle 14 into passage 20 to pressurize the patient's lungs. When the pressure in chamber 25 has fallen to a predetermined value, in a time dependent on the volume of chamber 25, which is adjustable by a movable piston 35, this low pressure acts through feedback passage 27 to switch the air jet from passage 17 to passage 19, to pressurize chamber 25 and, through duct 23, to switch the air jet of nozzle 14 from passage 20 to passage 18. Flow through passage 18 induces flow from passage 20 to evacuate the patient's lungs, for a period of time during which the pressure in chamber 25 builds up to a value sufficient to act through passage 27 to switch the air jet of nozzle 13 from passage 19 to passage 17, the cycle then repeating. The degree of evacuation is controllable by valve 33. In the Fig. 6 embodiment (not shown), the pilot respirator is omitted, control duct 23 being connected to the deformable chamber 25 and a branch from passage 20 also being connected to chamber 25 to pressurize and evacuate it, the pressure in the chamber 25 acting through the control duct 23 to control the switching of the jet. The respirator is formed between three superimposed plates, Fig. 4 and 7 (not shown).