| 摘要 |
1535277 Controlled frequency volumetric respirator R METIVIER 19 Jan 1976 [20 Jan 1975] 02022/76 Heading A5T Pharmaceutically operated respiratory apparatus for feeding air, oxygen or anesthetic to a patient comprises a breathing gas circuit and a control gas circuit, and is operable with a predetermined respiratory cycle frequency, insufflated volume per unit time, and inhalation/exhalation ratio. In one form of use, pressurized control gas at 120 gm/sq cm is fed either from compressor 1, or valve 2 connected to a pressure cylinder, to a first control valve 9 having a membrane 14 depressed by virtue of the attraction between adjustable magnet 15 and iron plate 30 such that valve member 11 is closed. The control gas therefore passes via line 5 to close valves 6, 7, and via line 33, needle valve 19, regulator 8 and constant flow line 17 to chamber 18c such that diaphragm 18a is caused to expel breathing gas or anesthetic from chamber 18b, via valve 21 to the patient P. During this time control gas bleeds via needle valve 16 to chamber 12 and ultimately overcomes the magnetic attraction between magnet 15 and plate 30. The membrane 14 thus moves up to close valve member 10 and open valve 11 to atmosphere. Valves 6, 7 thereby open and the pressure in chamber 18c is reduced to allow valve 20 to open and valve 21 to close. Breathing gas or anesthetic from bladder 22 thereby passes into chamber 18b for subsequent expulsion on the next cycle. Previously supplied breathing gas is exhaled via line 37, valves 23, 6 and filter 24 for subsequent return via line 39 with any oxygen or anesthetic introduced from rotameter 25. If the gas supply fails valve 26 opens to allow atmospheric air to be introduced. Once chamber 12 is drained via needle valve 16 the membrane is attracted towards the magnet again and the cycle is repeated. The circuitry includes a safety valve 27. The control gas may be supplied at a rate of 200 litres/min and a pressure of 120 gm/sq. cm. In a first modification, Fig. 2, the magnetic arrangement is replaced by a second membrane 14a which is acted upon by the pressure in line 28 and the needle valve 16a. The inhalation-exhalation times are determined by the surface area difference between membranes 14a, b. In a modified use of the apparatus the closed-circuit control fluid circuit is stopped and spontaneous respiration carried out. Atmospheric air may replace the oxygen/ anesthetic supply. |
