Patent GB-726140-A (GB)
Title: Inhaler
IPC: A61M16/18
Filed: 1953-06-23
Abstract: 726,140. Inhalers. AYERST, McKENNA & HARRISON, Ltd. June 23, 1953 [June 26, 1952 ; May 11, 1953], No. 17407/53. Class 81 (2). In an inhaler for the self-administration of a mixture of air and vapour comprising a longitudinal tube disposed within the inhaler body the air is drawn through a port at the bottom of the body to pass through a medicament chamber formed by the space between the body walls and the tube the air and vapour mixture then passing through a port in the tube and rising to the top of the body from which it is inhaled. The inhaler, as shown in Figs. 1 and 2, comprises an open ended outer body 1 to which is attached an outlet arm 3 and air or oxygen inlet tube 4. Within the lower portion of the body is disposed an assembly comprising tube 12 to which is attached a partition disc 33, a valve cage structure 35 and frusto-conical cone pieces 18, 32, 31, 30, 29 and 17, the pieces 18, 17, being formed with perforations 20, 19, whilst the pieces 32, 31 and 30, 29 respectively mask ports 16, 15 formed in the tube. The assembly also comprises a valve disc 54 placed within the cage 35, a partition wall 26 in the tube and a valve plug 21 adapted for insertion in the tube when the assembly is fitted in the body and the end body plate 7 soldered in. The pieces 17, 18 of the assembly are of such diameter that when the assembly is fitted within the tube they form means whereby a wick 14 is held within the body. The valve plug 21 is held within the tube by a spring 22 engaging grooves in plug and tube and a cut away portion 25<1> is so provided in the top of the plug that when the plug is rotated (by means of a key 42 engaging a bar 27 in the plug and the plug walls) to align the cut away portion with the tube port 15 air may flow through the plug to the chamber 28 formed between body 1 and tube 12. The top of the body is closed by a ported disc 6 below which is disposed a partition 36 formed with an aperture 39 closed by a valve disc 41 arranged within a cage 40. In operation when the valve plug is in the position shown in Fig. 2, all the air entering the inhaler passes to the chamber 28 which has previously been filled with liquid inhalant by inverting the inhaler and pouring the liquid through the plug 21. The mixture of air and vapour enters the tube through port 16 and after passing the one-way valve, comprised by 'disc 34 within cage 35, passes to the patient via arm 3. The mixture may be varied by rotation of the plug 21 and pure air alone may be passed to the patient via tube 12 by aligning the cut away portion 25' of the plug with the cut away portion 26<1> of the wall 26. The exhalation gases from the patient pass through the oneway valve comprised by disc 51 in cage 40 and ports 6 in the body end plate 5 to the atmosphere. In the modification shown in Fig. 9, the valve plug 21 is dispensed with, the air entering the inhaler through an inlet 58 and passing to the medicament chamber through port 65 the vapour and air mixture issuing therefrom through the tube port 66 and rising up the tube past the one-way valve assembly 84 to the outlet orifice 52. Control of the mixture quality is effected by a slidable partition assembly 86 which comprises a control knob 92 and a partition formed with a one-way valve 91. The control knob slides within a slot 93 provided in the inhaler body and is actuated in an upward direction against a spring 94. The top 55 is provided with air ports 56 and the knob 92 is provided with a spring loaded catch device which in co-operation with notches on one side of the slot 93, ensures that the knob and hence the partition assembly 86 stays in the position in which it is put. In operation the gas issuing from the orifice 52 is air, air and air and vapour mixture or just air and vapour mixture according to the position of the partition assembly 86. In both the embodiments described above the air and vapour proportioning means, i.e. the valve plug 21 and partition assembly 86 are only capable of adjustment by tool or key means but in a third embodiment which is very similar to that shown in Fig. 9, the knob 92 is .not provided with a catch device and the partition assembly, although spring loaded, has no one-way valve device similar to 91. Instead the partition assembly comprises a knob similar to 92 and a blank disc partition, no provision being made therefore for exhalation of the patient. The valve assembly 84 is dispensed with. Exhalation valve means in this embodiment are fitted in the face mask etc. to which the inhaler is connected.