US2906447A - Inflation equipment - Google Patents

Description

D. SEED INFLATION EQUIPMENT Sept. 29, 1959 3 Sheets-Sheet 1 Filed March 30. 1956 0 I ijV Q HO J 2 /1\ m m 6 5 6 7 J m 2 H M 23 78 M W Sept. 29, 1959 D. SEED 2,906,447

INFLATION EQUIPMENT Filed March 30, 1956 3 Sheets-Sheet 2 Attorney Sept. 29, 1959 D. SEED 2,906,447

INFLATION EQUIPMENT Filed March 30, 1956 3 Sheets-Sheet 3 F/GG.

Inventor United Sttcs Patent INFLATION EQUIPMENT Daniel Seed, Farnborough, England, asn'gn'or to Specialties Development Corporation, Belleville, N.J., a corporation of New Jersey Application March 30, 1956, Serial No. 575,176

13 Claims. (Cl. 230-116) The present invention relates to inflation equipment and in particular relates to inflation equipment for inflation bags such as the larger sizes of airborne rescue apparatus, i.e. inflatable dinghies which are inflated by means of gas stored under pressure in a container. In all equipment of this nature the weight of the gas bottle and its contents is considerable and if the weight of gas that has to be stored for inflation purposes can be reduced, it is possible simultaneously to reduce the weight of the gas bottle or other container for the gas.

It is an object of the present invention to provide a means by which an inflation bag can be inflated by a reduced quantity of stored gas.

It is well known that when gas is released from a gas bottle into an inflation bag, such as a dinghy, there is a tendency to the formation of ice in the release equipment due to the cooling associated with the rapid expansion of the gas. It is a further object of the present invention to try to reduce the tendency to icing by controlling the expansion of the gas so that it expands relatively slowly.

Since the gas in the gas bottle is at relatively high pressure and the pressure in the fully inflated inflation bag is very little in excess of atmospheric pressure, it follows that the gas is capable of doing useful work during the period in which it expands from the pressure at which it is held in the gas bottle to the much lower pressure which is maintained in the inflation bag. Such work can of course only be obtained from the gas if it is allowed to expand relatively slowly, i.e. in conditions approximating to isothermal conditions and not to adiabatic conditions.

It is proposed in accordance with the present invention to employ the energy obtainable from the expanding gas to draw external air into the inflation bag. In order to achieve this result the expanding gas must be employed to drive some sort of pump or like device. The simplest form of inflation apparatus made in accordance with the present invention incorporates an injector which draws in air and passes it through a check valve to the inside of the inflation bag. Although the construction of an injector is both light and cheap, which is desirable for the purposes of the invention, its efficiency as a pump is low,

sothat it is preferable to use a rather more complex and weighty pump device of greater mechanical efliciency.

It is preferred to employ in the inflation apparatus a small turbine driven by the expanding gas issuing from the gas bottle, the turbine in turn driving an air impeller to force air into the inflation bag.

Every inflation apparatus made in accordance with the present invention basically comprises a gas bottle or like container provided with a control valve or release mechanism through which the gas is released from the gas bottle or container, an air pumping device to which the gas released fromthe bottle is ducted to drive the said device and a checkyalve, preferably positioned in the *wall of the inflation bag. i v

One constructionmade in accordance with the present invention is shown in the accompanying drawings where.- m

Figure 1 is a longitudinal section through the device with the stator partially in section,

Figure 2 is a side view of the stator member,

Figure 3 is an end view of the stator member,

Figure 4 is a section of the rotor member,

Figure 5 is an end view of the rotor member,

Figure 6 is a partial longitudinal section of a modified form of device,

Figure 7 is a section on line XX of Figure 6.

The device shown in Figure 1 is intended to be secured directly in the wall of the inflation bag with which it is to be employed. For this purpose it is provided with a body casting 1 having an integral end plate or flange 2, which is adapted to be secured into the wall of the inflation bag by moulding or bonding. Alternatively the formation 2' on the body could be provided with screw threads to permitthe material of the inflation bag to be clamped against the flange Z by means of a clamp nut.

The body casting has end members 3 and 4 secured thereto and these in turn support a stator shaft 5 positioned axially of the body casting 1. A stator member 6 is mounted on the shaft 5, on which it is a push fit, and is pinned in position. The stator shaft is internally drilled at the inlet end and internally threaded to receive a fitting connecting it to the gas supply. The fitting, which is screwed into the end of the stator shaft 5, connects the device to one or more gas bottles through a valve of known construction. The space 7 formed by the internal drilling is connected by means of diagonal drilled holes 8 with the area around the stator member 6. Similarly at the outlet end, the gas is led out through diagonal drillings 9 into an internal passage 10. The axial location of the shaft 5 is determined by means of its screwthreaded end portion 11, which is secured in the end member 4 and also extends into the inflation bag. The free end of the screw-thread end portion 11 is employed to take a lightly-loaded non-return inlet valve (not shown) of known construction through which the gas from the passage 10 issues into the inflation bag.

On the stator thus formed a rotor system is mounted on ball bearings 12 and 14, the bearing 14 being a thrust bearing to take up the end thrust imposed on the rotor by the gas. The rotor structure comprises a rotor member 15, an end member 16 mounted on the bearing 12 and an end collar 17 on the bearing 14. In addition light annular rotary bronze or other metal seals 18 are included in the construction which are pressed outwardly by the pressure of gas in the space between the rotor and stator to prevent substantial leakage of gas out through the bearings 12 and 14, when the device is in use.

It will be appreciated from the foregoing description that the rotor and stator together form a turbine, in which the rotor is driven by the pressure of gas admitted through the inlet passage 7.

The construction of the stator member 6 is shown in Figures 2 and 3. The stator member 6 is in the form of a sleeve which is a push fit on the stator shaft 5, to which it is lightly pinned. The stator member is made from stainless steel but may equally be made from some other metal oi material which is finished in such a manner that is not readily oxidisable.

The stator member is formed with three spaced lands 20. The lands 213 of the stator member are cut to form helical grooves 21, which are twelve in number and have a helix angle of 45 in the left hand direction.

The rotor member 15 is made in two halves which are secured together by studs. The rotor member is preferably made of the same material as the stator member. l

The-rotor member 15. is formed with three lands 23,

in which helical grooves 24 are cut. The helical grooves are fourteen in number with a helix angle of about 30 in the right hand direction. This arrangement ensures that there. will always be a proportion of the grooves in the rotor and the stator in register with on another, so that gas can always pass through the turbine unit] The rotor 15 forms also the rotor of an air pump or impeller. As will be seen from Figure l, the rotor memher is provided with a plurality of fan blades 26, which may be replaced by other air impelling formations provided on the periphery of the rotor.

As the rotor member 15 is rotated by the admission of gas from a pressure supply to the turbine unit, so will the fan blades 26 draw air into the impeller unit through apertures 27 in the front end member 3. It will be observed that the space between the rotor member 15 and the body casting 1 decreases between the inlet and outlet ends of the impeller, boththe interior surface of the casting 1 and the exterior surface of the rotor 15 being tapered for this purpose. This reduction of the space between the rotor and the casing is necessary to secure the compression of the indrawn air to permit it to be discharged to the inflation bag through a nonreturn valve, the interior of the inflation bag necessarily being at a pressure slightly in excess of atmospheric pressure.

The fan blades 26 are arranged in three rows and the blades are necessarily of decreasing length between the inlet and outlet ends of the impeller. There are six blades in each row, all the blades being of equal pitch and the blades in adjacent rows being 20 out of pitch with each other.

The air drawn through the air impeller thus constituted is delivered to the inflation bag through apertures 28 formed in the outlet end member 4. The apertures 28 are closed by non-return valve comprised by rubbery disc 29. The loading of this disc is very light so that it readily lifts to admit air into the inflation bag when there is only a small pressure difference.

The advantages obtained by the turbine inflator device thus described are:

(a) A considerable reduction in the weight of gas stored under pressure and a corresponding reduction in the weight and volume of the apparatus needed for storing it,

(b) Air is used for inflation in addition to the carbon dioxide or other gas stored under pressure,

(c) The relatively slow expansion of the pressurised gas through the turbine unit with the accompanying induction of atmospheric air reduces the freezing troubles commonly experienced at the outlet end of the gas pressure line from the bottles to the inflation bag,

(d) An air-sea rescue dinghy inflated by this means will require less than the usual few minutes for warming up before reaching its designed pressure, as is usual where carbon dioxide under pressure alone is the inflation medium.

The modified construction shown in Figures 6 and 7 has been designed to produce an inflator device, which is somewhat more efficient in operation than the device shown in Figure 1, although there is an increase in weight as compared with the previous example.

The construction of the turbine unit is identical in both examples and will not be further described.

In the present construction a modified body casting 31 has a cylindrical bore therein, with bearing portions 32 at each end thereof, which are in contact with the outer surface of a cylindrical rotor 33, preferably formed of oil-impregnated sintered bronze material. In this construction the fan blades 26 are mounted in the rotor 33. The rotor 33 is driven by means of ring gear 34 secured thereto, which is in mesh with a pair of spur gears 35 mounted on bearings carried on a modified end mem which is provided with internal teeth and meshes with a pinion 38 freely rotatable on an inwardly projecting boss 39, which is integral with the end member 36.

By this means a considerable reduction is obtained in the rotational speed of the air impeller rotor, which in the present example is geared so that the fan rotor 33 makes 36 revolutions to 102 revolutions of the turbine rotor 15.

The advantages of having the impeller rotor geared down are several. Principally the advantage is that the resistance offered by the impeller is reduced so that the turbine does not stall until the gas inlet pressure reaches a lower value.

Additional advantages are that by reason of the two rotors rotating in opposite directions, the twist to which the flanges 2 are subjected is reduced so that there is less strain on the bond between the inflator device and the wall of the inflation bag than there would otherwise be.

I claim:

1. An inflation device for an inflation bag comprising, in combination, a casing providing a chamber having inlet openings in fluid flow communication with the atmosphere and outlet openings adapted to be in fluid flow communication with the inflation bag; a turbine stator shaft in said chamber having an internal inlet bore adjacent the chamber inlet openings for connection to a compressed gas supply and an internal outlet bore adjacent the chamber outlet openings and adapted to be in communication with the inflation bag; a turbine stator member rigidly mounted on said shaft and provided with nozzle means; an annular turbine rotor member mounted radially outwardly of said stator member for rotation about said stator and having turbine vane means adjacent said nozzle means, said rotor member being spaced from the side wall of said chamber to provide an annular air passage therebetween; and air impelling means in said annular passage driven by said rotor member for drawing air from the atmosphere through said inlet openings and forcing the air through said outlet openings.

2. An inflation device according to claim 1, wherein the surface of said rotor member and said side wall of said chamber are convergent with respect to each other to progressively decrease the cross section of said air passage toward said outlet openings to effect compression of air impelled through said passage.

3. An inflation device according to claim 1, wherein said air impelling means is mounted on said rotor member for rotation therewith.

4. An inflation device according to claim 1, wherein are provided a cylindrical rotor positioned radially inwardly of said casing and radially outwardly of said turbine rotor, and driving means between said turbine rotor and said cylindrical rotor, said air impelling means being mounted on said cylindrical rotor.

5. An inflation device according to claim 4, wherein are provided a sun gear connected to said turbine rotor for rotation therewith, planetary gears driven by said sun gear, and a ring gear connected to said cylindrical rotor and driven by said planetary gears.

6. An inflation device for an inflation bag comprising in combination, a casing providing a chamber having inlet openings in fluid flow communication with the atmosphere and outlet openings adapted to be in fluid flow communication with the inflation bag; a turbine stator shaft in said chamber having an internal inlet bore adjacent said chamber inlet openings for connection to a compressed gas supply and an internal outlet bore adjacent said chamber outlet openings and adapted to be in fluid flow communication with the inflation bag; a turbine stator member rigidly mounted on said shaft and having a plurality of longitudinally spaced nozzle means; an annular turbine rotor member rotatably mounted radially outwardly of said stator member and spaced from the side wall of said chamber to provide an air passage therebetween, said rotor member having a plurality of longitudinally spaced internal vane means; and a plurality of longitudinally and circumferentially spaced air impeller blades in said air passage driven by said rotor member for forcing air through said outlet openings.

7. An inflation device according to claim 6, wherein said air impelling means are mounted on said rotor for rotation therewith.

8. An inflation device according to claim 6, wherein are provided a cylindrical rotor positioned radially inwardly of said casing and adjacent thereto, and driving means rotably connecting said turbine rotor member with said cylindrical rotor, said air impelling means being mounted on the inner surface of said cylindrical rotor.

9. An inflation device according to claim 6, wherein said stator member is provided with a plurality of longitudinally spaced external lands having a plurality of nozzle grooves and said motor member is provided with a plurality of longitudinally spaced internal lands positioned between said external lands and having a plurality of vane grooves.

10. An inflation device according to claim 9, wherein said nozzle grooves are helical and said vane grooves are helical and of the opposite hand.

11. An inflation device according to claim 10, wherein the number of said nozzle grooves is different than the number of said vane grooves, said nozzle grooves and said vane grooves being positioned so that a portion of said nozzle grooves are in register with a portion of said vane grooves in any angular position of said rotor.

12. An inflation device according to claim 11, wherein said impeller blades are positioned in said air passage in longitudinally spaced circumferential rows, said impeller blades being set at a diiferent pitch in each row to aid in compression of the impelled air.

,13. An inflation device for an inflation bag comprising, in combination, a casing providing a chamber; inflation bag attachment means on one end of said casing; a first end wall enclosing said chamber and positioned adjacent said attachment means and radially inwardly thereof, said end wall having a central opening and radially disposed openings; at second end wall enclosing the opposite end of said chamber and having a central opening and radially disposed openings; a turbine stator shaft extending through said chamber and said central openings in said first and second end wall, said shaft having an internal outlet bore adjacent said first end wall and an internal inlet bore adjacent said second end wall; a turbine rotor rotably mounted radially outwardly of said stator and spaced from the side Wall of the chamber to provide an annular air passage between said radially disposed openings in said first and second end walls; and air impeller means in said air passage driven by said rotor.

References Cited in the file of this patent UNITED STATES PATENTS 910,036 Wolfson Jan. 19, 1909 958,768 Richardson May 24, 1910 2,007,777 Standerwick July 9, 1935 2,271,627 Coppus Feb. 3, 1942 2,399,670 Freygang May 7, 1946 2,684,784 Fox July 27, 1954 2,693,905 Carter Nov. 9, 1954 FOREIGN PATENTS 8,899 Great Britain June 12, 1884 411,473 France June 17, 1910

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