GB835192A - Pressure breathing therapy apparatus - Google Patents

Abstract

835,192. Respiratory appliances. STANTON, P. L. Aug. 6, 1958, No. 25245/58. Class 81 (2). Breathing apparatus comprises pressureoperated means which is preloaded by superatmospheric fluid pressure when fluid flow to the patient is stopped, and which is actuated by the preloading pressure to start flow of gas to the patient in response to a negative pressure created on inhalation. First and second chainbers 8, 9 in a three-part housing 1 are separated by a diaphragm 10. Gas under pressure is supplied to the housing through a hose 20 and passes via a manually-adjustable main valve 24 through first passages 12, 13, 14, 15 to a sectional inhalation hose 17 connected to a mask 18 or a mouthpiece. The first chamber 8 is connected to the mask 18 through an exhalation hose 31. Second passages 33, 34 connect the first chamber to a discharge port 35 controlled by a check valve. One, 14, of the first passages is connected with the second chamber through a third passage 42. Spring-loaded toggle mechanism 47 in the second chamber is connected with the diaphragm and controls three valves 49, 50, 51 in the first, second and third passages respectively. The outer end of one toggle arm 61 is slidable between adjustable nuts 66 on the stem 52 of the first and third valves 49, 51 and has an extension 72 which bears against the stem 54 of the second valve 50 which is spring-urged against its seat. A fixed guide and stop 68 limits the movement of the first toggle arm 61. The outer end of the other toggle arm 60 moves between stops 62 on a fixed pin 63. The first chamber has safety valves 75 opening when the negative and positive pressures, respectively, exceed predetermined amounts. A medicament vaporizer unit 78 may be provided in the inhalation hose 17. The second chamber, which is maintained at a predetermined positive pressure, may be vented through a manually-adjustable valve 81. During exhalation through the hose 31 the diaphragm and toggle mechanism are in a first position, thus opening the second and third valves 50, 51 and closing the first valve 49 so that gas is cut off from the mask 18 but flows into the second chamber to load the diaphragm, and exhaled air passes from the first chamber to atmosphere. At the commencement of inhalation, the pressure drop in the first chamber is sufficient for the diaphragm and the toggle mechanism to move to a second position so that the first valve 49 is opened and gas flows to the mask, the second and third valves 50, 51 being closed. As soon as the pressure in the lungs and the chamber 8 reaches a predetermined value, the diaphragm and the toggle mechanism are moved again into the first position for exhalation. In a modification, a single hose for exhalation and inhalation connects the mask and the first chamber 8 into which one of the first passages leads. The housing may be suspended from or connected directly to the mask.