US3033426A

US3033426A - Fluid projection apparatus

Info

Publication number: US3033426A
Application number: US786345A
Authority: US
Inventors: David A Young
Original assignee: Aerojet General Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1959-01-12
Filing date: 1959-01-12
Publication date: 1962-05-08
Anticipated expiration: 1979-05-08

Description

1 y 1962 D. A. YOUNG 3,033,426

FLUID PROJECTION APPARATUS Filed Jan. 12, 1959 INVENTOR. DAVID A. YOUNG ATTORNEY United States Patent Ofiice 3,633,426 FLUKE) l RGJECTIQN APPARATUS David A. Young, Washington, D.C., assignor to Aeroget- General Corporation, Azusa, Calif., a corporation of Ohio Filed Jan. 12, 1959, Ser. No. 786,345 7 Claims. (Cl. 222-3865) 'The present invention relates to fluid projection apparatus and particularly to such apparatus adapted for use in flame throwers, fire extinguishing apparatus, pressurization devices and the like.

An object of the present invention is to provide a novel method of and an improved means for the projection of fluids.

Another object is to provide an improved fluid projection apparatus of the free piston type.

Still another object is to provide improved fluid projection apparatus of the piston type wherein the fluidpropelling piston may follow a convoluted or non-linear ath.

P In its preferred embodiment, the invention comprises a portable fluid projection apparatus such as a portable flame thrower incorporating a fuel tank of convoluted form and circular cross section. Gas under pressure is admitted to the tank on one side of a piston therein. Fuel in the tank on the opposite side of the piston is ejected therefrom by the admitted gas pressure driving the piston through the length of the tank. A fuel ejection nozzle is mounted at the exit end of the tank for etficient discharge and direction of the fuel.

A principal feature of the present invention is the use of a piston not connected to any other portion of the apparatus and hereinafter designated as a free piston. The piston of the present invention is also characterized by having a periphery effective to seal against the walls of a tubular tank, whether of straight, curved or folded configuration, thereby keeping separate the fluids contained in the tank on opposite sides of the free piston, regardless of the pressure acting on the fluids.

These and other objects and features of the invention will hereinafter appear from the following specification read with reference to the accompanying drawings where- FIG. 1 is a longitudinal section of a preferred embodiment of the present invention utilizing a free piston in the form of a ball;

FIG. 2 is a cross sectional view on the plane 2-2 of FIG. 1;

FIG. 3 is a longitudinal section through a second form of free piston;

FIG, 4 is a view taken on the plane 4-4 of FIG. 3;

FIG. 5 is a longitudinal section through a third form of free piston;

FIG. 6 is a view taken on the plane 6--6 of FIG. 5;

FIG. 7 is a longitudinal section of a fourth form of free piston; and,

FIG. 8 is a view taken on the plane 88 of FIG. 7.

Referring nowto FIG. 1, the device is shown as having a U-shaped tank 10 of uniform circular cross section. A gas generating chamber 11 having a removable head closure 11b is mounted on one removable end 11a of the tank and a detachable nozzle mounting member 12 is mounted on the other end, the nozzle 12b being closed by any suitable closure 12a until the device is put into use.

A gas chamber 11 is shown as one way of supplying pressure fluid to the tank but it is immaterial to the invention how pressure is supplied. For example, a container storing gas or hydraulic fluid under pressure might be connected to the inlet end of the tank and controlled by a valve of any suitable type.

A gas generating chamber 11, which is provided with a removable head closure 11b, contains a grain or charge 13 of slow burning propellant. A free piston 14 is positioned initially adjacent the gas inlet 15 from the chamber 11 when the grain 13 is ignited by any suitable means such as a squib and electrical connector indicated at 11c.

Free piston 14 may be formed from a suitable elastomer as a solid ball as shown, or as a hollow ball, and the surface of the ball 14 is preferably sufliciently resilient to insure that effective sealing is provided notwithstanding minor imperfections of the inner surface of the tank 10. A suitable material for the piston is an elastomer such as a synthetic rubber of 20-40 Shore hardness and resistant to heat and to the action of various corrosive fluids or fuels acting to soften or dissolve natural rubber.

The space in the tank between the free ball piston 14 and the nozzle mounting member 12 is filled with the fluid 16 to be expelled. v

When the grain 13 is ignited, gas under pressure enters the tank 10 and forces the ball piston 14 toward the nozzle 12b until all the fluid has been expelled, the force exerted by the fluid initially rupturing or blowing off closure 12a.

The cross-sectional area of the tank 10 is slightly widened at its terminus in the nozzle mounting member 12 so that the seal between the piston 14 and the walls of the tank 10 is broken when the flexible piston 14 reaches this point. This permits the pressurizing gases or fluids to completely exhaust all of the material being pumped.

When the device is employed as a flame thrower suitable ignition means (not shown) are arranged to ignite the ejected fluid to form a burning stream. Such means are well known in the art. See, for example, assignees copending U.S. patent application No. 786,348, filed January 12, 1959.

When the ball piston 14 is nested in the enlarged portion 12c of the detachable nozzle mounting member 12, the latter can be demounted and the ball piston 14 removed, the nozzle member 12 replaced, and a fresh closure 12a put in position.

After removal of end 11a of the tank 10, it can be re charged with fluid 16, the ball piston 4 placed in the tank 10, the tank end 11a replaced, and a fresh grain of slow burning propellant 13 is positioned in chamber 11, after which the device is ready for reuse. The form of the free piston shown in FIGS. 3 and 4 differs from that previously described with reference'to FIG. 1 in that the free piston is formed or molded as a hollow ovel body 17 having an open end 18 facing toward the gas opening 15 when positioned in the tank 10. Reinforcing or stiffening means 19, which may be formed as a thick walled tube of synthetic rubber, is arranged around the maximum inner diameter of membgr 17 and cemented in place with a suitable adhesive 2 l The free piston shown in FIGS. 5 and 6 comprises a hollow body open at one end so that gas or fluid may enter the body thereof.

The free piston 21 shown in FIG. 5 comprises a cuplike outer body of molded synthetic rubber having a molded lip 22 formed to provide an inwardly projecting flange 23. An extension type resilient member comprising a plurality of curved metal strips 24 extend from a center cupped disc 25 secured to the forward wall 26 of the piston 21 by a member 27 extending forwardly. Member 27 is intended to aid removal of the free piston 21 from the tank 10 by pulling on the exposed forward end of the member 27, or to aid insertion into the tank 10 by pushing on the rearward end of the member.

The rearward ends of the fingers 24 tend to maintain Patented May 8, 1962 It the piston 21 in normally extended position. The side walls 28 of the free piston 21 are shaped to afford a certain amount of pliability in passing around small radius curves in the tank yet will be erected to normal form after passing through such curved portions.

The form of the free piston 29 shown in FIGS. 7 and 8 is a variation of the form of free piston 17 shown in FIGS. 3 and 4. The free piston 29 is cup-shaped with its open side positioned toward the gas entry 15. The wall 29:: is positively kept in open position by a plurality of flat spring fingers 30 struck from a sheet to leave a central disc 30:: secured to the center of the cup by a rivet 31. It will be evident that the rivet 31 may be substituted by a securing member formed similarly to the member 27 shown in FIG. 5.

This piston cup wall 290: may be molded from a suitable elastomer such as a synthetic rubber, with an inturned rim 32 covering the ends of the spring fingers 30.

In operation of the various forms of the invention, the wall of the ball piston 14 slides along the inner surface of the tank 10, the surfaces sliding at different rates round the smaller diameter curved surface and the opposite larger diameter curved surface at bends in the tank without losing efiective sealing contact therewith. The various forms of the free piston shown, and others which may be devised, operate in the manner described and are elfective to separate fluids on opposite sides of the piston while transmitting pressure from one side to the other of the free piston.

Several preferred embodiments of the invention have been specifically described and shown by way of example only and not as limitative of the invention since changes may be made therein by those skilled in the art without departing from the scope of the invention as defined by the claims appended hereto.

I claim:

1. Fluid projection apparatus comprising: an elongated tubular tank of constant area of cross section and having a longitudinal axis arcuately formed in part, said tank adapted to contain fluid to be expelled therefrom by pressure fluid admitted thereto; an inlet to and an outlet from said tank; and a free piston shaped to provide a peripheral surface in sealing engagement with the inner surface of the tank throughout the travel of the free piston through the tank under the force exerted on said piston by pressure fluid admitted to said tank to expel fluid in said tank between said piston and the outlet from said tank.

2. Fluid projection apparatus comprising: an elongated tubular tank of constant area or circular cross section and having a longitudinal axis arcuately formed in part, said tank adapted to contain fluid to be expelled therefrom by pressure fluid admitted thereto; an inlet to and an outlet from said tank; and a spherical free piston having a diameter such that a peripheral portion of its surface remains in sealing engagement with the inner surface of the wall of the tank throughout the travel of the free piston through the interior of the tank.

3. Fluid projection apparatus as set forth in claim 2 and in which said spherical piston is made of an elastomer having a hardness of from about 20 to about 40 Shore and resistant to deterioration by the fluids contained in the tank.

4. Fluid projection apparatus comprising: an elongated tubular tank of constant area of cross section and having a longitudinal axis arcuately formed in part, said tank adapted to contain fluid to be expelled therefrom by pressure fluid admitted thereto; an inlet to and an outlet from said tank; and a free piston having a hollow body of greater length than width, closed at one end, and open at the opposite end, and of circular cross section at all sections taken normal to its longitudinal axis. said open end being faced toward the inlet of the tank through which fluid pressure is supplied to the tank, the diameter of said body increasing from that of its open end to a maximum at a point intermediate its ends and thereafter decreasing to a minimum diameter at the end opposite its open end, said piston having a maintained shape while propelled by said pressure fluid and having sealing engagement with the inner surface of the said tank throughout the piston travel.

5. Fluid projection apparatus as set forth in claim 4 and in which said free piston comprises resilient means positioned within the piston and engaging the inner surface of the wall thereof to effect stiffening thereof.

6. Fluid projection apparatus comprising: an elongated tank of constant cross section having a longitudinal axis arcuately formed in part, said tank having an inlet and an outlet, said tank being adapted to contain fluid to be expelled from its outlet by pressure fluid admitted to its inlet and a free piston arranged within said tank, said piston comprising a cup-like body of moldable material, and resilient means within said body effective to maintain the normal form of the body while moving in certain portions of the tank in response to pressure fluid actuation and also permitting said piston to pass through other portions of the tank having a nonlinear longitudinal axis, in sealing engagement with the inner surface of the tank throughout the piston travel.

7. Fluid projection apparatus comprising: an elongated tank of constant area of cross section and longitudinal axis arcuately formed in part, said tank adapted to contain fluid to be expelled therefrom by pressure fluid admitted thereto; an inlet to and an outlet from said tank; a free piston having a cup-like body of flexible resilient material placed in said tank with its open end facing the inlet to the tank through which fluid pressure is introduced into the tank; and flat resilient strips secured to the closed end of and within the cup-like body to resiliently maintain the cup-like contour of said body while positioned in and moving through the tank, under the force of said fluid pressure to expel fluid through the tank outlet.

References Cited in the file of this patent UNITED STATES PATENTS 708,448 Wyman Sept. 2, 1902 1,320,858 Hitch Nov. 4, 1919 1,699,494 Schmidt Jan. 15, 1929 2,361,647 Nyden Oct. 31, 1944 2,872,083 Murphy et al. Feb. 3, 1959 2,880,913 Peyron Apr. 7, 1959 FOREIGN PATENTS 3,610 Great Britain Feb. 10, 1897 202,156 Great Britain Aug. 16, 1923 791,113 France Sept. 23, 1935