US2785838A - Aerosol dispenser - Google Patents

Description

AEROSOL DISPENSER Filed Oct. 18, 1954 denial Car] Hflayay fix United States Patet AEROSOL DISPENSER Carl H. Mayer, Jr., Wilmette, 111., assignor to Safe, Ind, Marinette, Wis., a corporation of Wisconsin Application October 18, 1954, Serial No. 462,639

6 Claims. (Cl. 222394) This invention relates to aerosol-type dispensers and has particular relation to the valve assembly incorporated therein.

In dispensers producing a directed spray of powder or liquid, usually as aerosols and commonly called aerosol bombs, the various problems encountered in manufacture and use are usually centered on the valve assembly. These problems are usually intensified when a dry powder is the material to be ejected as a fine suspension. In dispensers of this general nature, a valved, pressurized container is employed, the container being provided with a quantity of the powder or other material to be ejected, together with a quantity of gas under pressure, to provide the ejection pressure and also help suspend the powder or other particles. It is desirable, of course, that the dispensing action be as complete as possible so that little of the powder is wasted by being left in the container and that the flow should not be impeded by turbulence introduced by the valve or other parts of the structure. A dispenser should also lend itself to economical operation whereby a large charge of powder may be ejected from a given size container and with a given quantity of pressurized gas. Naturally, the pressurized vessel itself must be capable of withstanding the pressures involved and the valve must not only be positively closed until operated but it must very completely seal so that no loss of pressure is involved over the period of time before the dispenser is used. At the same time, the valve must be positively actuated without causing or being subject to sticking or gumming of the dispenser contents.

In dry powder fire extinguishers, especially, rigid requirements as to positive, simple, and consistent operation must be met. No deterioration of the valve with time can be tolerated. To assure foolproof operation for smaller sizes of extinguishers, it is additionally desirable that the valve remain open after once being actuated without further attention until all the contents are ejected, thus avoiding return of a partially discharged extinguisher to the shelf. it is also especially desirable in dry powder fire extinguishers that the suspension of powder be accurately directed for a number of feet with an adequate powder concentration, together with the requirement that the spray should not contain lumps of powder nor should the expelled powder be wetted by a liquid-state pressurized gas. It is desirable likewise that the spray be capable of being directed at various angles with respect to the horizontal without requiring adjustment or special attention by the user.

It is therefore an important object of my invention to provide an improved aerosol-type spray dispenser.

It is also an object of my invention to provide an improved dry powder fire extinguisher.

It is another object of my invention to provide a pressure seal valve for an aerosol-type dispenser which does not leak and which is positive in action.

It is a further object of my invention to provide a valve assembly for an aerosol spray which is particularly ice useful for completely and economically dispensing dry powders as an aerosol spray.

It is another object of my invention to provide an aerosol dispenser which can be directed at a wide range of angles with respect to the horizontal.

It is still another object of the invention to provide in an aerosol dispenser a non-reclosable valve assembly.

it is a further object to provide in an areosol dispenser a simple and improved construction which is economical to manufacture and foolproof in operation.

Other objects and advantages of the invention will become apparent from the detail description of the preferred embodiments disclosed in the accompanying drawings, in which:

Figure 1 is a View, partly in section, of a dry powder fire extinguisher showing its valve in the normally closed position.

Fig. 2 is a view, partly in section, showing the apparatus of Fig. l in use to produce a horizontal spray.

Fig. 3 is a simplified view, partly in section, showing the apparatus of Fig. 1 in use to produce a downwardlydirected spray.

Fig. 4 is a detailed View of a modified dispenser assembly.

Fig. 5 is another modification of the valve of the apparatus of Fig. 1.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein be described in detail the preferred embodiments, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications, alternative construction and equivalents falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to Fig. 1, the fire extinguisher shown therein comprises a valved pressure vessel in which the vessel suitably takes the form of a cylindrical steel can 1 having a concave bottom 2 and a top 3 sealingly crimped over the rolled top edge of the can. The can itself is of conventional design, being adapted for high production manufacture at a relatively low cost and much used for sealing various household products under pressure. A cap 4 is usually positioned over the top of a can of this nature to protect the sealed top assembly and is also designed for attractiveness. This cap is removed before using the can.

Before the top of the vessel has been sealed and crimped in place, a charge of the finely divided fire extinguishing powder 5 is inserted followed by a charge of the gas 6 to be used for expelling the powder under pressure. This gas charge is preferably introduced substantially in liquid state.

An elongated outlet orifice for the suspended powder is provided by a dip tube 7, suitably made of a length of steel tubing. This tubing is inserted into an aperture in the can top 3 and soldered in place, the solder also providing a pressure-tight gas seal. The bottom portion of the tubing is a gradually curved section 8 extending toward one corner of the can, stopping a distance short thereof, while the upper section 9 extending above the can top is bent over at an angle, preferably in the range of 3060 from the horizontal and here shown at 45 to form an outlet nozzle. The smooth uninterrupted passage provided by the dip tube makes laminar flow, and thus rapid flow, possible. No abrupt change in the direction or cross section area of the tube is involved at the nozzle end of the tube, nor is friction introduced by a valve structure near the nozzle. The aperture in the top 3 is preferably located off center in order that the short nozzle end S of the dip tube does not interfere with the placement of the cap 4. It will be noted that while the angle or radius of curvature of the upper and lower parts of the tubing is not necessarily the same, the curvature is all in the same plane and in the same direction.

The actual valve element or valve plug seats on the lower end of the dip :tube 7, being held in place by the can internal pressure. The resilient plug is preferably made of synthetic rubber formed to have a flat bottom or inner surface 11 which fits Within the end of the dip tube and a tapered surface 12 which is sealed against the end or" the tube by the pressure of the can content. A shoulder 13 on the plug provides a positive limit of the upward displacement of theplug into the dip tube end. While the conformation of the outer end of the valve plug is not critical, it is shown in this instance as conical. The plug dimensions are such that the plug may be pushed out to clear the end of the dip tube and leave an unobstructed outlet passage Without fouling of the plug on the can walls or bottom.

An actuating stem for the valve plug suitably takes the form of a straight section of resilient wire 14, prefer:

ably stainless steel, which is disposed for most of its length within the dip tube 7.' The wire has a much smaller diameter than the inside diameter of the dip tube. The lower end of the stem is tightly fitted into. a central aperture in the face 11 of the small diameter portion of the valve plug 14 and the upper end of the stem is fitted place provides the means for forcing substantially all of the powder out of the cans. powder and would escape freely should the lower end of the tube be exposed or uncovered. With the upper end of the dip tube directed upwardly at an approximate 45 angle with respect to .the horizontal, the can when held in the upright position of Pig. 1 is efiective to direct spray upwardly, and the can may be tilted upward for near overhead fires without direct escape of the gas until most of the powder has been used. For the most likely use of the extinguisher to provide a horizontal spray the can is tipped forward 45 as shown in Fig. 2. This is also the most natural attitude for a hand, held container of this size and permits maximum expulsion of the powder charge. Similarly, as shown in Fig; 3, the can may be tipped further downwardly for extinguishing floor fires. The curvature of the lower portion of the clip tube in the same plane and general direction as the more abruptly curved upper or nozzle portion permits the can to be tipped to a full horizontal position without preventing the ejection of almost the full powder charge from that position. No swiveling of the spray direction by swiveling the top portion of the dip tube is involved, and hence I the curavtu-re of the lower portion always remains the through a bore 15 in the external dip tube portion 9.

This bore is suitably made with a tapered drill in the dip tube near the 45 nozzle curvature to provide a fairly close but sliding fit for the wire and prevent escape of the powder around the protruding upper stem portion. To facilitate depressing the stem for opening of the valve at the bottom of the dip tube, the upper end 16 of the wire stem is preferably flattened out in nailhead fashion. A taper 17 from below the nail head to the unaltered body of the wire is preferably provided so that when the head is depressed the distance required to push the plug out of the end of the dip tube, the tapered portion 16 fits snugly within the tapered bore in the tube.

To provide the nonreclosing operation of the valve, the stem or operating wire 14 is not permanently bent or deformed to conform to the curved axis of the lower section of the dip tube, but instead is elastically strained between the upper portion of the dip tube and the plug 10 at the lower end, thus placing a lateral bias on the plug. In the apparatus of Fig. l the wire 14 is straight before being inserted in the curved dip tube.

To operate the valve, the head 16 of the stem is de pressed, the can 1 being suitably of such a size that it can be grasped in the users hand and the head 16 depressed by his thumb. The axial motion transmitted through the stem'wire 14 thus forces the valve element 10, out from the end of the tube, Only a small force is needed to open the valve and the force on the valve tending to reseat the valvev is decreased as the valve is opened to a point where the flat bottom plug surface 11 is beyond the end of the dip tube. The resilient valve stem 14 tends to straighten out and in so doing, as indicated in Fig. 2, it moves the plug 1% laterally so that it is no longer centered for reclosing. As shown in the figure, the portion of the stem wire adjacent the plug rests directly on the end of the hollow dip tube and the flat surface 11 of the plug obstructs its movement back into the dip tube seat. The operators thumb pressure is thus no. longer required for maintaining the valve open. The length of the stem travel necessary to unseat the valve governs the minimum spacing between the lower tube end and the can walls and also the travel of the upper stem end containing the taper 17 into the bore 15 in the dip tube.

As shown in Figs. 2 and 3, the configuration of the dip tube permits the extinguisher to be used in a number of positions so that the spray may be directed at substantial v angles upwardly or downwardly from the horizontal without preventing full use of the powder contents of the can. The location of the end of the dip tube in the first same with respect to the nozzle curvature.

l have found that with such novel construction, poWder-to-gas ratios of the nature disclosed and claimed inthe copending application of Kenneth B. Covert, Serial No. 606,028, filing date, August 4, 1956, may be very advantageously employed. Although reference should be made to such copending application for a more detailed disclosure of the powder-to-gas ratio, it may be helpful here to describe one particular application in which my 'a'bove'describ'ed valve and dispenser are used. in a can of the nominal one-quart size and having about 23 cubic inches of free space when empty, I employ about 12 ounces of sodium bicarbonate in finely divided powder form. On this powder charge I add a charge of 9 grams of dichlorodifiuoromethane. The elfectiveness of the discharge is assured by'the smooth, open laminar flow path through the dip tube, the valve plug being substantially out of the flow path due to its position at the lower end of the dip tube. With a can of these dimensions and the charge mentioned, an approximate 10 foot spray covering a three foot diameter is maintained for about 5 seconds or more, which is su-fficient to blanket the fire area with the powder.

A similarly advantageous non-reclosirrg self-sealing valve action may also be obtained with the use of a dip tube having a straight lower portion. A construction adapted for this use is indicated in Fig. 4 in which a fiatbott-omed bottle or container 18 suitably made of glass or low pressure dispensers is provided with a straight dip tube 19 which extends vertically from the bottle cap 20 to within a short distance of the bottom of the bottle;

A valve plug 21, suitably in the shape of a tapered cylin to spring back to its original position, thus retaining the valve in an open position. It will be appreciated that other means for biasing the stem laterally relative to the dip tube may be'employ'ed such as, for example, making the dip tube more resilient or less stiff than the stem and imparting to the dip tube a different permanent curvature than that of the stem. Such a tube stressed within its elastic limits when the valve is in the closed position tends to return to its normal ")OSllilOIlwhen; the valve is open, thus preventing'reclosi-rrg, a

As shownin Fig. 5, the apparatus may be modified to provide a self-sealing reclosable valve action but still re- The gas is lighter than-the tain the valve at the bottom end of the otherwise open dip tube. A valve plug 23 is positioned on the end of a stem 24 within the lower end portion of the dip tube 25. Yo lateral bias between the stem and tubing is necessary, bot having the same degree of curvature, or both being straight, as may be desired. The plug, however, has a gradually tapered seating section 26, preferably extending smoothly to the diameter of the stem wire itself, so that after actuation of the valve by depression of the stem, the stern and plug are free to return upwardly. The tapered section 26 guides the plug so that it is centered as it re-seats under the internal pressure. A spring is preferably also used to assure prompt resenting, a helical wire compression spring 27 surrounding that external portion of the stem between the stern head, and the stem opening on the dip tube being suitably employed for this purpose.

i claim as my invention:

1. A valve assembly for a pressurized vessel comprising a dip-tube having its lower end within said vessel, 2. push wire of substantially smaller diameter than said tube siidable within said dip-tube, and a valve plug attached to one end of said wire seatable on the lower end of said tube, at least one of said wire and said tube being curved and at least one of said wire and said tube being resilient to laterally displace the plug when it has been axially nnseated, said plug having an obstructing portion engageable with the lower end or" the dip-tube to prevent reseating.

2. A self-sealing non-reclosable valve assembly comprising a valve plug adapted to be seated on the pressurized side of an orifice member, and a resilient valve em attached to said plug and extending through the orifice, said plug being laterally biased when in the seated position by elastic strain of the valve stem and having an obstructing portion engageable with the orifice member to prevent reseating when the plug has been axially unseated and laterally displaced.

3. A pressure vessel having a curved dip-tube sealed therethrough and extending toward the bottom surface of the vessel, a resilient Wire stern having a portion slidable within said dip-tube and of substantially smaller diameter than said tube, and a valve plug attached to the lower end of said stem seatable on the lower end of said dip-tube, the upper end of said stem slidably extending through the wall of the upper portion of the dip-tube outside of the vessel to provide actuating means for axially depressing said stern and valve plug.

4. An aerosol dispenser comprising a cylindrical pressure vessel, 2. dip-tube sealed through the top of the vessel, said dip-tube having a curved upper external nozzle portion directed at an oblique angle with respect to the cylindrical axis of the vessel and a lower internal portion extending near a bottom corner of the vessel under the nozzle portion, a push wire having a portion slidable within said dip-tube and of substantially smaller diameter than said tube, and a valve plug attached to the lower end of said wire and seatable on the lower end of said dip-tube, the upper end .of said wire slidably extending through the wall of the upper external portion of the diptube to provide actuating means for lifting said plug from the lower end of the dip tube.

5. A cylindrical pressure vessel for dispensing powder or the like having a dip-tube sealed through the top of the vessel, said dip-tube having a curved upper external nozzle portion directed at an oblique angle with respect to the cylindrical axis of the vessel extending near the bottom of the vessel, a resilient push wire of substantially smaller diameter than said tube having an elastically laterally strained portion slidable within said dip-tube, the upper end of said wire slidably extending through the Wall of the upper external portion of the diptube to provide external operating means, and a valve plug attached to the lower end of said wire seated on the lower end of said dip-tube, said valve plug having a flattened portion engageable with the lower end of the tube to obstruct reseating of the plug when the plug has been unseated and laterally displaced by the push wire.

6. A powder dispensing pressure vessel having a curved dip-tube with a smoothly continuous inner surface sealed therethrough, said tube having an upper external nozzle portion and a lower internal portion extending toward the bottom surface of the vessel, a resilient wire stem having a portion slidable within said dip-tube and of substantially smaller diameter than said tube, a valve plug attached to the lower end of said stem sealingly seatable on the lower end of said dip-tube by internal pressure, the upper end portion of said stem slidingly extending through an aperture in the upper portion of the dip-tube outside of the vessel, said stem having an enlarged diameter upper end portion whereby the tube aperture is sealed and the lower end of the tube is opened when the upper stem end is depressed.

References Cited in the file of this patent UNITED STATES PATENTS 1,118,977 Watrous Dec. 1, 1914 1,163,927 Hughes et a1 Dec. 14, 1915 1,463,093 Pearson et a1 July 24, 1923 1,499,451 Etzenhouser July 1, 1924 2,270,063 Linch Jan. 13, 1942 2,613,016 Jarrett et a1. Oct. 7, 1952

Images