US 3528461 A
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p H. GROTHOFF APPARATUS FOR FILLING AEROSOL PACKAGES Filed Sept. 26, 1968 H/ws 620mm:
United States Patent Office 3,528,461 Patented Sept. 15, 1970 US. Cl. 14120 10 Claims ABSTRACT OF THE DISCLOSURE An apparatus for filling aerosol packages includes a filling head provided with a cavity into the open end of which the valve of an aerosol package may be sealingly inserted. A dosing cylinder is adapted to receive a quantity of fluid. A piston is reciprocable in the dosing cylinder from a retracted to an advanced position to thereby raise the pressure of fluid to a predetermined value. Passages connect the interior of the cylinder with that of the cavity so that pressurized fluid may enter the latter and subsequently the aerosol package. A first valve normally closes the passages and opens when the pressure of fluid in the cylinder reaches the predetermined value. A second valve is located upstream of and adjacent to the first valve and closes the passages when the piston reaches its advanced position.
BACKGROUND OF THE INVENTION The present invention relates to apparatus for filling of aerosol packages, and more particularly to an apparatus for admitting liquefied propellant into such aerosol packages.
Propellants used in aerosol packages may basically be classified as to whether they are admitted under relatively low compression or under relatively high compression. The present invention is particularly concerned with liquefied propellants, that is liquefied gases such as carbon dioxide or dinitrogen oxide, which are admitted un der high compression and which need be supplied for propellant purposes only in small quantities of approximately 0.3 grams to 5 grams per aerosol package. This is contrary to low-compression gases, such as fiuorated chlorine hydrocarbons. However, these small quantities must be metered with high precision and this precision must be reproducible because under these pressures variations in the dosage admitted will appear as pressure variations in the aerosol package in approximately the same proportion as the variation in the admitted dosage. This makes it highly desirable that a tolerance of :5% in the exactness of metering should be maintained.
Of course, devices for admitting low-compression liquefied gases into aerosol packages are already well known. However, they are not capable in this instance of fulfilling the aforementioned requirements. In the case of high-compression gases the liquified gas is compressed by a piston to a maximum of 80 atmphospheres and introduced via a filling head through the outlet valve of the aerosol package into the latter. As soon as the piston used for compressing the gas has reached its end position the pressure in the spaces surrounding the outlet valve in the filling head, as well as in the various fluid passages through which the gas in admitted into the filling head, will decrease until it reaches the basic pressure of the liquefied gas at the existing temperature. This pressure is at most approximately 5 atmospheres where lowcompression gases are involved. In the case of highcompression gases the pressure is at least ten times that of the low-compression gases. If one considers that the outlet valve of the aerosol package must be subjected to a pressure of at least 10 atmospheres in order to open it for purposes of introducing the liquefied propellant gas into the package, it will be understood that these surrounding spaces in the filling head, hereafter for purposes of convenience designated as residual spaces, will not be emptied of gas if the gas is of the low-compression type. On the other hand, if the gas is of the high-compression type a certain subsidiary emptying will take place. This is where the problem occurs which the present invention is intended to overcome because the residual spaces are relatively large as considered with respect to the small quantities of gas which are to be introduced into the aerosol package; therefore, subsidiary emptying of the residual spaces results in unacceptably high fluctuations in the quantities of gas admitted into the aerosol packages, particularly because the degree of subsidiary emptying of the residual spaces is depended upon many factors and cannot be maintained constant. Moreover, the quantity of gas which enters the aerosol package as a result of the aforementioned subsidiary emptying usually is a multiple of the quantity which it is intended to introduce, thus precluding the introduction of small gas quantities in most cases.
It is therefore a general object of the present invention to overcome the aforementioned disadvantages.
A more particular object of the invention is to provide an apparatus for admitting highly compressed propellant fluids'into aerosol packages in such a manner that the gas can be introduced in precisely metered relatively small quantities and that no significant fluctuations in the quantity of thus admitted propellant fluid will occur.
Still more specifically it is an object of the invention to prevent or at least reduce to an absolute minimum the introduction of propellant fluid into aerosol packages as a result of subsidiary emptying after the intended quantity of propellant fluid has already been introduced into the package.
SUMMARY OF THE INVENTION Pursuant to the above objects and others which will become apparent hereafter, one feature of my invention resides in the provision of an apparatus for admitting a compressed fluid, particularly a highly compressed liquefied propellant, through the valve of an aerosol package into the interior of the latter. My novel apparatus comprises filling head means which is provided with a cavity having an open end adapted to sealingly receive the valve of an aerosol package. A dosing cylinder means is adapted to reecive a quantity of fluid therein. Piston means is reciprocable in the dosing cylinder means from a retracted first position to an advanced second position to thereby raise the pressure of fluid in the cylinder means to a predetermined value. Passage means communicates with the interior of the cylinder means and of the cavity to admit pressurized fluid into the latter and to admit it subsequently into the aerosol package. First valve means normally closes the passage means and is adapted to open in response to the pressure of fluid in the cylinder means reaching the aforementioned predetermined value. Finally, second valve means is provided upstream of and adjacent to the first valve means and is operative for closing the passage means in response to the piston means reaching the aforementioned advanced second position thereof.
Advantageously the second valve means is constituted by a valve seat in the passage for fluid entering from the dosing cylinder means into the cavity of the filling head, and by a projection provided at the front end of the piston means which will enter into the passage and into sealing engagement with the valve seat when the piston means advances to its advanced position. Thus, it will be the piston means itself which will effect, after it has injected the requisite quantity of propellant into the aerosol package, closing of the passage for incoming fluid to thereby cut off at least the largest portion of the volume of the residual space so that any compressed propellant present in the thus cut-E residual space cannot against the intended purposes enter into the aerosol package.
The valve seat may be formed by providing the passage into which the projection enters with an inwardly projecting shoulder, that is stepping the passage down from a larger to a smaller diameter, and securing on this shoulder an annular sealing ring into engagement with which the projection will move when the piston moves to its advanced position. Because such a shoulder and sealing ring can be provided almost immediately adjacent upstream of the filling valve which normally prevents communication between the passage and the interior of the cavity in the filling head until the propellant in the dosing cylinder has been subjected to requisite elevated pressure, the actual residual space from which subsidiary emptying of compressed propellant into the aerosol package in addition to the intended quantity of propellant may take place, can be very small. It is, in fact, advantageous if the volume of the incoming passage for compressed fluid intermediate the valve which is closed by the piston and the filling valve is at most equal to 10% of the minimum quantity of fluid which is to be introduced into an aerosol package.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING The single figure is a fragmentary vertical section of an exemplary embodiment of my invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Discussing now the drawing in detail it will be seen that reference numeral 1 identifies a wall portion which will be assumed to be the end wall of an aerosol package, the latter not being illustrated in detail. In conventional manner this end wall 1 carries the dome-shaped casing 2 of an outlet valve, the actuating stem of this valve being identified with reference numeral 3 and the pushbutton actuating head being identified with reference numeral 4. Such constructions are conventional and very well known in the art and they therefore are not believed to require further description. It will suflice to recall that the valve is located within the casing 2 and that it is normally opened by exerting downward pressure (as seen in the drawing) upon the head 4 and thereby upon the valve stem 3. The contents of the package will then issue through the valve stem and through a nozzle provided in the head 4 and not visible in the drawing.
A filling head is identified with refeernce numeral 5 and provided with a recess 6 in which the head 4, the valve stem 3 and the casing 2 are receivable in the manner illustrated. When thus received, the casing 2 will be engaged by an O-ring 7 or similar sealing means so that inwardly of the O-ring 7 the recess 6 is completely sealed from the ambient atmosphere so that no propellant can escape from the recess 6.
Reference numeral 8 designates a dosing cylinder arranged to receive in its interior a quantity of propellant fluid through the inlet channel 10. This propellant fluid will be supplied in form of a liquefied gas, and the inlet channel has installed therein (but not illustrated) a suitable valve which is opened when it is intended to admit liquefied propellant gas from a (non-illustrated) source through the channel 10 into the interior of the dosing cylinder 8. A piston 9 is reciprocable in the dosing cylinder 8 between an advanced position (illustrated) and a retracted position. How the piston is reciprocated between these positions is well known and not believed to require description, particularly because it does not form a part of the invention. Similarly, the arrangement for opening and closing the non-illustrated valve interposed in the inlet conduit 10 synchronously with advancing and retracting of the piston 9 is well known and not illustrated for this reason.
The front end of the piston 9 carries a projection 11 which in the advanced position of the piston 9 enters into a channel 12 which penetrates a projecting portion 15 of the dosing cylinder 8. The projecting portion 15 is introduced through the open rear end of the filling head 5 and sealed against escape of fluid by means of the sealing element 21 which may be a conventional O-ring or the like. The front end face of the portion 15 is in the illustrated embodiment provided with an axial recess into which the cylindrical portion 14 of an insert is screwthreadedly introduced as illustrated. The insert further comprises a radially projecting shoulder portion 18 which is located in the recess or cavity 6 and carries on its surface which faces the end face of the cavity 6 a sealing element 19', which again may be an O-ring, so that when the sealing element 19 engages the end face bounding the cavity 6 will constitute therewith a first valve. The insert is provided in the portion 14 thereof with a passage 16 constituting an extension of the passage 12 and communicating with the latter; further, one or more radially extending passages 14 are provided at the front or leading end of the pasage 16 and the open ends of these radially extending passages 17 will be sealed against escape of fluid when the sealing element 19 engages the bottom face bounding the cavity 6. This is the position illustrated in the drawing.
Where the wider passage 12 and the. narrower passage 16 meet, there is provided a radially inwardly extending shoulder which in the illustrated embodiment carries a sealing ring 13 which surrounds the inlet end of the passage 16. The forward portion of the projection 11 may be conical as illustrated, or it may be otherwise configurated; in any case, it will seemingly engage the sealing ring 13 when the piston '9 is in its advanced position in which it has ejected the liquefied fluid which has entered the dosing cylinder 8 through the conduit 10, and which has been thereupon subjected to a pressure increase during advancement of the piston 9 to its advanced position, into the cavity 6. Thus, the projection 11 and the sealing ring 13 together constitute a second valve which is very closely upstream adjacent the first valve.
The portion of the filling head on which both valves are located is identified with reference numeral 20 in the drawing. It will be appreciated that relative axial movement of the members 5 and 8 is possible and that the members 5 and 8 are urged away from one another by the presence of the biasing spring 22 which bears against both of them in the manner illustrated. With this biasing action provided by the spring 22 the first valve, namely the valve constituted by the members 18, 19 and the bottom face bounding the cavity 6, will normally be closed. The biasing force provided by the spring 22 is such that this valve will not open when liquefied propellant is admitted through the conduit 10 into the interior of the dosing cylinder 8 with the piston 9 in retracted condition. Only when the piston 9 moves towards its advanced position and the liquefied propellant is therefore further compressed, will the point be reached where the pressure exerted by the compressed liquefied propellant will exceed the biasing force of the spring 22, whereupon in the illustrated embodiment the member 8 will move downwardly with respect to the member 5, so that the portion 18 and the sealing element 19 will move out of engagement with the bottom face bounding the cavity 6, thereby opening the first valve for admission of the compressed propellant into the cavity 6 from whence the propellant enters through the nozzle in the head 4 and the valve stem 3 to exert a suflicient opening pressure upon the valve in the valve casing 2 so that it will be able to enter into the aerosol package.
As soon as the piston 9 has reached its advanced position the projection 11 will sealingly engage the sealing ring 13 and will prevent any further intrusion of pressurized propellant through the passage 16, 17 into the cavity 6. This makes it impossible for any subsidiary emptying to take place, that is the subsidiary emptying of any compressed propellant upstream of the valve constituted by the projection .11 and the sealing ring 13 is preclude'd. The quantities of compressed propellant which are located downstream of the valve constituted by the projection 11 and the sealing ring 13, that is in the passage 16, 17 are relatively small as compared with the quantity of propellant which it is intended to introduce into the aerosol package and which has already been introduced thereinto. Advantageously the construction will be such that they are at most equal to 10% of this quantity and the apparatus can be so constructed that they will not normally exceed 0.02 gram. These quantities will expand under simultaneous reassumption of gaseous state until their pressure has dropped to the closure pressure of the valve in the casing 2. Because these quantities are small as compared with the quantity which it is intended to introduce into the aeroeol package, and because the closure pressure of the valve of the aerosol package can be considered constant, the accuracy of metering of the introduced quantity of propellant will be considerable even where only small quantities of propellant are introduced into the aerosol package, and this accuracy can be reliably maintained. In order to obtain a uniform and reproducible subsidiary emptying of the passage 16, 17 it is advantageous if there is some delay provided between closure of the valve consisting of the projection 11 and the sealing ring 13 and the removal of the filling head from the aerosol package. It is also advisable to provide means for controlling the temperature of the filling head 5 so as to prevent icing-up of the same.
It will of course be appreciated that the illustrated embodiment is by may of example only. Clearly it is possible to so modify it as to cause the piston 9-when the same reaches its advanced position as illustratedto close the valve consisting of the members 18, 19 and the bottom face bounding the recess 6. This prevents even the subsidiary emptying of compressed propellant from the passage 16, 17. Furthermore, it would be possible to eliminate the sealing ring 13 and to provide the projection 11 with a flat front face which would engage a similarly flat annular face on the shoulder provided at the juncture of the passages 12 and 16. Alternately, the flat front end face of the piston 9 itself could engage a similarly configurated fiat face at the inlet end or upstream end of the passage 12.
Particularly where small quantities of aerosol propellant are to be introduced into a package, it is advantageous to use a type of filling head which permits introduction of the propellant into the valve of the aerosol package with the head 4 removed. Filling heads of this type are already known and need not be further described, and it remains merely to point out that evidently with such constructions the volume of the recess or cavity 6 can be considerably smaller than that illustrated in the drawing. This results in a correspondingly smaller expansion of the propellant subsequent to the introduction of the requisite quantity into the aerosol container, and assures a higher precision of metering. Also, the filling head will not be subjected to as strong cooling as a result of the expanding gas as is the case with the type illustrated in the drawing.
Other modifications will of course offer themselves readily to those skilled in the art, and it will be obvious that the provision and configuration of the passages may be different from what is illustrated, and that for instance the connection between the member consisting of the portions 14 and 18 and the portion 15 of the cylinder 8 may be different. However, as regards this particular construction as illustrated in the drawing, it will be appreciated that it facilitates the inspection and replacement of the various sealing elements if and when needed.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:
1. An apparatus for admitting a compressed fluid, particularly a highly compressed liquefied propellant, through the valve of an aerosol package into the interior of the latter, comprising filling head means provided with a cavity having an open end adapted to sealingly receive the valve of an aerosol package; closing cylinder means adapted to receive a quantity of fluid therein; piston means reciprocable in said dosin g cylinder means from a retracted first position to an advanced second position to thereby raise the pressure of fluid in said cylinder means to a predetermined value; passage means communicating with the interior of said cylinder means and of said cavity to admit pressurized fluid into the latter and subsequently into the aerosol package; first valve means normally closing said passage means and adapted to open in response to the pressure of fluid in said cylinder means reaching said predetermined value; and second valve means upstream of and adjacent to said first valve means and operative for closing said passage means in response to said piston means reaching said advanced second position.
2. An apparatus as defined in claim 1, said cavity having an other open end, said filling head means and said closing cylinder means being axially movable with reference to one another, and said first valve means including a first valve seat surrounding said other open end internally of said cavity and a first valve portion provided on said dosing cylinder means and projecting through said other open end into said cavity and normally engaging said valve seat.
3. An apparatus as defined in claim 2; and further comprising biasing means biasing said filling head means and said dosing cylinder means axially away from one another to thereby normally maintain said first valve portion in engagement with said first valve seat.
4. An apparatus as defined in claim 3, said second valve means including a second valve seat provided in said passage means upstream of said first valve seat, and a second valve portion carried by said piston means projecting forwardly therefrom and arranged to sealingly engage said second valve seat in response to movement of said piston means to said second position thereof.
5. An apparatus as defined in claim 4, said passage means being provided with an internal annular shoulder facing in upstream direction, said second valve seat including an annular sealing ring overlying said shoulder, and said second valve portion being arranged to sealingly engage said annular sealing ring.
6. An apparatus as defined in claim 2, said first valve portion including a substantially cylindrical section extending through said other open end and a circumferential shoulder projecting radially at the leading end thereof and adapted to engage said first valve seat, said passage means including a first passage portion extending axially through said cylindrical section and terminating short of the leading end thereof, and a plurality of second passage portions emanating radially from said first passage portion in the region of said shoulder and having free ends which are closed when said shoulder engages said first valve seat.
7. An apparatus as defined in claim 6, said cylindrical section being provided with an axial recess facing the interior of said cavity, and said first valve portion comprising an insert having one insert portion received in said recess rigid with said cylindrical section, and another insert portion located exteriorly of said recess and constituting said circumferential shoulder.
8. An apparatus as defined in claim 7, said recess and said one insert portion respectively being provided with mating screw threads.
9. An apparatus as defined in claim 3, said biasing means comprising a compression spring bearing against said filling head means and against said dosing cylinder means in a sense urging the same axially away from one another.
10. An apparatus as defined in claim 4, said passage means having intermediate said first and second sealing means a volume which is at most equal to 10% of the minimum quantity of compressed fluid which is to be admitted into the aerosol package.
References Cited UNITED STATES PATENTS HOUSTON S. BELL, 1a., Primary Examiner US. Cl. X.R.