US 3056540 A
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1962 J. o. MARSH ET AL INFLATION DEVICES Filed March 14, 1960 M/I/E'A/TOkB MARSH DERRICK H. POHL ER JOHN ATTOE/VFXS lflatented Get. 2, 1962 Free 3,056,540 HNFLATKGN DE'VTQES John Oliver Marsh, Greeniord, and Derrick Marshall Pohler, Harrow, England, assignors to The Walter Kidde Company Limited, Greent'ord, England Filed Mar. 14, 1960, Ser. No. 14,637 Claims priority, application Great Britain Mar. 18, 1959 Claims. (Cl. 23t)95) The present invention relates to an inflation device and more particularly to an aspirator device or use in connection with the inflation of large inflation bags, such as large airborne inflatable dinghies and inflatable escape chutes for aircraft.
It is usual to inflate such equipment by the release of compressed gas from storage cylinders. It has however, been found that very large quantities of atmospheric air can be drawn into the inflatable equipment, if an aspirator device is employed, which uses the kinetic energy of the gas released from the storage container. This permits a very considerable reduction in the quantity of stored gas and, in consequence, permits a considerable economy in weight to be made.
When inflated, the internal pressure of an inflation bag of the type mentioned should be a little above that of the ambient atmosphere. As the inflation proceeds, the pressure in the inflation bag builds up and the outlet pressure of the storage container tends to fall away, so that there comes a point at which the stream of gas from the storage is no longer able to induce more air into the inflation bag against the back pressure of the contents of the bag. The pressure of the contents of the bag may still be insuflicient for operational purposes at this point, whilst the storage container still holds some residual gas at a substantial pressure, which could be used to top up the contents of the inflation bag to a higher pressure.
It is an object of the present invention to provide an aspirator device for the present purpose in which the air passage for the aspiration of atmospheric air is closed off automatically when the aspirating function of the device ceases, whilst thereafter the remaining contents of the storage container discharge into the inflation bag to top up the pressure of its contents.
According to the present invention an aspirator device comprises a body, adapted to be secured in the wall of an inflation bag and having a passage therethrough, the passage in said body having at least one gas outlet nozzle arranged therein for connection to a gas storage supply and positioned to direct a stream of gas towards the outlet end of the body, the said body having a supplementary check valve means arranged in said body outwardly of the nozzle and adapted to close automatically to prevent outflow of gas from the body to atmosphere and a main check valve means arranged inwardly of said nozzle and loaded towards the closed condition to prevent outflow of gas from the inflation bag into the body. A springloaded clamping means may also be employed to act on the main check valve means to hold it in the closed position, the said clamping means being held inactive until the pressure of gas in the storage container falls below a predetermined value,
In operation the main check valve closes when the back pressure in the inflation bag rises to a point where the, aspiration of further atmospheric air is checked. The closure of the main or inner check valve causes a rise in pressure in the aspirator body from the continued flow of gas from the storage container. The supplementary or outer check valve then closes, after which pressure in the body builds up again to cause the inner check valve to open. The remaining contents of the storage container then discharge into the inflation bag until the pressure in the storage container drops to a point where the spring-loading acting on the inner check valve is once more etfective to close it. The outer check valve, which may be a simple flap valve, may be permitted to open after the inner check valve has finally closed.
It is a particular advantage of the aspirator of the present invention that as a result of its mode of operation, the inflation bag is inflated to a pressure which only slightly exceeds atmospheric pressure, but is in fact always in excess of atmospheric pressure, provided. the stored g s is suflicient.
In one construction an aspirator is constructed so that the air passage through it is bent round through approximately a right angle near its mouth end. The body of the aspirator can thus be quite long, as is required for eflicient aspiration, without projecting for a long distance in a direction perpendicular to the inflation bag wall, in w ich it is to be secured. A flange surrounds the mouth of the aspirator and is provided for fastening to the material of the inflation bag.
The invention is hereinafter described with reference to the accompanying drawings wherein,
FIGURE 1 is a longitudinal section of one construction of aspirator;
FIGURE 2 is a longitudinal section of a modified construction; and
FIG. 3 is a front elevation view of a part of FIG. 1.
The aspirator device shown in FIGURE 1 comprises a moulded plastic body 1, in which a plurality of threaded inserts 2 are moulded in a flange 3 around a rectangular inlet aperture 4. The body 1 is secured in the wall of an inflation bag by clamping the fabric (not shown) of the bag between the flange 3 and a ring 5 by means of screws 6 threaded into the inserts 2.
The aperture 4 is provided with a rubber flap valve member 7, which is integral with a gasket 8. The flap valve member 7 is provided with a rigid backing member 9 and is biased towards the closed condition by a light leaf spring 10. It is however adapted to open when the ambient atmospheric pressure only slightly exceeds the pressure on the back of the flap valve member 7.
At the outlet end of the body a main valve seat member 11 is secured in position to co-operate with a rubber valve disc 12 backed with a rigid disc 14. The members 12 and 14 are supported on a clevis member 15 hinged to a member 16, which is in turn hinged to a member 17 secured in the body. The main valve disc 12 is held against the valve seat member 11 by means of a tension spring 18.
The passage through the body 1 is substantially rectangular at any section taken at right angles to its centre line, indicated at 19 in FIGURE 1. It is shaped to have its minimum cross section approximately mid-Way between its ends so as to give aventuri effect.
It will be observed that the passage through the body is bent round sharply close to the inlet. By this arrangement the body 1 lies close against the wall of an inflation bag to which it is secured and this render the aspirator less of an obstruction when the inflation bag is folded.
Gas from a pressure storage is brought into the aspirator body through a hollow connector bolt 2%, which is connected by a curved pipe 21 with a nozzle block 22, in which are formed a pair of symmetrically positioned nozzles 23, as seen clearly in FIG. 3.
In operation the direction of the high velocity jets of gas from the nozzles 23 through the passage in the body causes a reduction in pressure in the region of the flap valve 7 and this opens to permit air to be drawn intO and through the body 1. So long as the velocity of the gas jets is suflicient for the gas and air stream to hold open the main valve disc 12 against the restoring force of the spring 18, air will be induced into the inflation bag.
When the gas in the storage is nearly exhausted, the velocity of the gas jets will fall away and the main valv disc 12 is closed against its seating by the spring 18. This leads to an increase in the pressure within the body 1 and the subsidiary valve 7 closes. The pressure in the body 1 then rises above atmospheric pressure and the valve disc 12 then opens again and as the remainder of gas from the storage passes to the inflation bag, which is thus topped up to a pressure a little in excess of atmospheric pressure. When the gas is exhausted the main valve disc 12 is closed by its spring. After this it is immaterial whether the valve 7 remains closed or not.
The construction of aspirator device shown in FIGURE 2 is the same in principle as that in FIGURE 1. The subsidiary valve at the inlet end of the body is diagrammatically indicated. The main valve at the outlet end comprises a flap valve 30, pivoted at 31 and loaded towards its seating by a light spring (not shown). It is ordinarily clamped against its seat by a clamp lever 32 pivoted at 33 and pivotally connected to a plunger 34,. which is acted on by a spring 35 to move the lever 32 in the clamping direction. The action of the spring 35 is opposed by the inlet pressure of gas from the storage, which is applied to the plunger 34, which is in sealed relation with a cylinder 36 to which gas is led through a connection 37, so that the clamping lever is held ineffective until the storage gas pressure falls away as the storage approaches exhaustion.
The mode of operation of this modified aspirator device is the same as that of the construction described in FIGURE 1, except that the main flat valve may be subjected to a greater spring load to hold it closed.
1. An aspirator device comprising an elongated, waisted body having a curved gas passage therethrough with an air inlet aperture at one end thereof and an outlet aperture at the other end thereof, said passage being curved through approximately a right angle, said body having a mounting flange thereon surrounding said inlet aperture, flap valve means mounted in said body adjacent said inlet aperture for closing said inlet aperture when the pressure within said body exceeds atmospheric pressure, non-return valve means mounted in said body adjacent said outlet aperture for closing said outlet aperture, said non-return valve means being spring loaded to close before said flap valve, nozzle means in said body positioned to direct at least one jet towards said outlet aperture, and means connected to said nozzle means for admitting gas under pressure to said nozzle means, said body being waisted between said nozzle means and said outlet aperture.
2. An aspirator device comprising an elongated body having a passage therethrough, said body having a mounting flange on one side and towards one end thereof, said passage having an inlet aperture bounded by said mounting flange, said passage having an outlet aperture in the opposite end of said body, said passage having a reduced cross section between said inlet aperture and said outlet aperture, nozzle means within said passage and secured to the side wall thereof, said nozzle means being located between said inlet aperture and said reduced cross section and being positioned to direct at least one jet towards said outlet aperture, means connected to said nozzle means for admitting gas under pressure to said nozzle means, spring-loaded non-return valve means at said outlet for closing said outlet aperture, and subsidiary non-return valve means at said inlet aperture for closing said inlet aperture, said non-return valve means being spring-loaded to close before said subsidiary non-return valve means.
3. An aspirator device as claimed in claim 2, wherein said nozzle means comprises a nozzle block having a pair of parallel nozzle orifices therein and a curved inlet tube connected to said nozzle block at one end and passing outwardly through the mounting flange at its other end.
4. An aspirator device as claimed in claim 2, wherein the non-return valve means at the outlet aperture comprises a seating in the end of said body and a valve member hinged to said body adjacent said outlet aperture spring-loaded towards said seating.
5. An aspirator device as claimed in claim 4 in which said non-return valve means further comprises a cylinder in said body, means for admitting gas under pressure to said cylinder, 'a piston in said cylinder, spring means pposing the movement of said piston in said cylinder under pressure of gas, a clamp lever pivotally connected to the external surface of said body and adapted to press said valve member against said seating, linkage means connecting said clamp lever to said piston in such manner that movement of said piston against the resistance of said spring means on admission of gas to said cylinder serves to rock said clamp lever in a valve opening direction.
References Cited in the file of this patent