Patent GB-191210428-A (GB)
Title: Improvements in or relating to Apparatus for use in Administering Gas for Medical or like purposes.
Inventor: BOULT ALFRED JULIUS
IPC: A61M16/12
Filed: 1912-05-05
Granted: 1913-02-20
Abstract: 10,428. Boult, A. J., [Clark & Co., A. C.]. May 2. Inhalers.-In an anesthetic apparatus, nitrous oxide and oxygen, or any other two gases, can be administered separately at any desired rate or mixed in any proportion by the operation of a single valve; any proportion of the gas or mixture of gases can be impregnated with ether, chloroform, or other volatile anesthetic; exhalation to the atmosphere may be stopped completely or only partly, so causing complete or partial rebreathing; and the passages connecting the gas cylinders to the regulating- valve are opened only by the proper attachment of the cylinders. The valve casing 4 is mounted on a stand 1, and has a bore or bush 11, Figs. 3 and 5, with ports 12, 13, 14 leading respectively to passages 7, 8 from the gas-bags 47, and to a chamber 15 having an outlet 16 to the hose 5 and inhaler 6. The rotary plug valve 10 has corresponding ports and is made hollow so as to serve as a mixing-chamber 17; it is yieldingly held in place longitudinally by a projection 10<a>, washer 18, and spring 19, and is provided with a handle 21 and a pointer 22 moving over an indicator dial. From extensions 4<a> of the casing extend hollow arms 24, Fig. 4, each closed at the outer end by a spring valve 26 and formed with a yoke 24<a> in which the head of the gas cylinder 34 is placed with its passage 37 fitted over a hollow rod 31 attached to the valve 26, so that when the screw 38 is tightened to hold the cylinder in place the valve 26 is forced off its seat and the passage 25 is open to the cylinder. Each extension 4<a> also supports a tubular arm 39, Fig. 3, with a globular end 39<a> to which the gas-bag 47 is attached, each globe having a check-valve 45 and a tubular connexion 40 to its passage 7 or 8. When the cylinder valve is opened, gas passes through the passage 25, the annular passage 41 between the tubes 39, 40, and through the passage 42 to the gas-bag 47; from the gas-bag through the valve 45, globe 44, tube 40, and passage 7 or 8 to the valve 10, mixing-chamber 17, port 14, chamber 15, and outlet 16 to the inhaler 6. When the ether or chloroform attachment, Fig. 10, is employed, it is secured to the outlet 16, the hose 5 being transferred to the outlet 59. It comprises a tube 53 on which the rebreathing bag is secured at the lower end, a valve casing 54 which supports the ether jar 70, a rotary plug-valve 56 having a transverse passage 60 at an angle to the passages 65, 66, and corresponding ports 57, 58, and 63, 64 in the casing; the valve has also a handle 71 with a pointer moving over an indicator dial. The gas or mixture of gases from the outlet 16 passes to the rebreathing bag, through the tube 53, and is either passed directly through the passages 57, 60, 58 to the face-piece, or is completely or partly bypassed through the ether jar by the passages 63, 65, 66, 64. The transverse passage 60 is preferably at such an angle to the passages 65, 66 that when the direct path through passages 57, 60, 58 is closed, the by-pass through the ether jar is open to at least some extent, so as to reduce risk of suffocation. The breathing bag may be arranged between the ether jar and the inhaler, or it may be dispensed with by using a nitrous oxide bag without a check valve 45. The exhaling valve 75 of the facepiece 6 is normally closed by a spring 82, but may be withdrawn from the port 76, so as partly or fully to open the outlets 77, by means of a handle 80 adapted to be turned to engage deep or medium notches 81, 83 or the end of the valve casing.