Apparatus For Filing Aerosol Packages

Abstract

The metering cylinder of an apparatus for admitting gaseous or liquefied propellant into aerosol packages accommodates a reciprocable plunger which is hollow and is connected to the piston of a pneumatic cylinder. The metering cylinder is separably connected with a filling head and is provided with an internal annular space for lubricant which surrounds a portion of the plunger. The filling head and the metering cylinder are provided with jackets for circulating conditioning fluid which withdraws heat developing on compression of gaseous propellant. The space for lubricant is flanked by two annular seals which are respectively installed in the metering cylinder and in the pneumatic cylinder. The inlet of the metering cylinder can receive gaseous or liquefied propellant, depending on the setting of a three-way valve which is installed in a conduit containing a pump for liquefied propellant and a valve which regulates the pressure of gaseous propellant.

Description

BACKGROUND OF THE INVENTION

The present invention relates to apparatus for filling aerosol packages, particularly for introducing gaseous or liquefied propellants into the containers of such packages.

In the art of aerosols, liquified propellants are those substances which are liquid at a pressure of 10 atmospheres superatmospheric pressure and at a temperature of 20.degree. C. Such substances include butane, propane, vinyl chloride and fluoridated chlorohydrocarbons such as difluordichlormethane. The characteristic pressure of gaseous propellants at a temperature of 20.degree. C. exceeds 40 atmospheres superatmospheric pressure; these include carbon dioxide, laughing gas and certain inert gases, such as nitrogen. As a rule, presently known apparatus for filling of aerosol packages with liquefied propellants are not suited for filling with gaseous propellants, mainly because the sealing elements for the plunger of the metering cylinder cannot stand extended use when the plunger is not lubricated by liquefied propellant. Another drawback of conventional apparatus is that there is too much dead space between the metering cylinder and the filling head and that no provision is made to withdraw heat which develops on compression of gaseous propellants prior and during introduction into aerosol packages.

SUMMARY OF THE INVENTION

An object of my invention is to provide an apparatus which can be used with equal advantage for filling of aerosol packages with gaseous or liquefied fluids.

Another object of the invention is to provide an apparatus wherein heat developing on compression of gaseous propellants is withdrawn in a novel and improved way.

A further object of the invention is to provide the apparatus with novel means for lubricating the plunger of the metering cylinder.

An additional object of the invention is to provide an apparatus wherein the temperature of metering cylinder, its plunger and filling head during admissions of gaseous propellants can be regulated and maintained with greater accuracy than in presently known apparatus.

Still another object of the invention is to provide an apparatus which can be rapidly converted from filling of packages with liquefied propellants to filling of packages with gaseous propellants, or vice versa.

Another object of the invention is to provide novel conditioning means for the filling head and metering cylinder of an apparatus for admission of propellants into aerosol packages.

A further object of the invention is to provide an apparatus which can be designed to fill containers with propellants in rapid sequence and in such a way that each of a seccession of aerosol packages receives the same amount of gaseous or liquefied propellant.

The improved apparatus comprises a preferably upright metering cylinder defining a metering chamber having in its lower end wall propellant-admitting inlet means and propellant-evacuating outlet means, a hollow plunger reciprocably extending into the metering chamber, a lubricant-receiving annular space preferably provided in the upper end wall of the metering cylinder and surrounding a portion of the plunger, annular sealing elements flanking the lubricant-receiving space to seal the supply of lubricant against entry to the metering chamber and against escape into the cylinder of a drive which reciprocates the plunger, a filling head separably connected with the lower end wall of the metering cylinder and having an inlet connected with the outlet means and a normally sealed outlet which can receive the valve on the container of a aerosol package, hollow jackets provided on the filling head and metering cylinder, a source of conditioning fluid, and means for circulating conditioning fluid from the source, through the jackets and back to the source when the apparatus is used for admission of gaseous propellant.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

The single FIGURE is a schematic partly elevational and partly sectional view of a filling apparatus which embodies the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The drawing illustrates an apparatus which is utilized for introduction of gaseous or liquefied propellants into aerosol packages 28. The apparatus comprises an upright metering cylinder 2 having an annular upper end wall 5 which is separably connected to the lower end wall 4 of a second cylinder 1. This cylinder 1 forms part of a drive means for a hollow plunger 6 which is reciprocably received in the metering cylinder 2 and extends upwardly through the end walls 4 and 5. The drive means further comprises a piston 3 which is reciprocable in the interior of the cylinder 1 and is rigidly connected with the upper end of the plunger 6. The cylinder 1 is of the double-acting type and is operated by compressed air or other suitable pressurized fluid medium. The conduits which deliver and evacuate fluid from the upper and lower chambers of the cylinder 1 are indicated at 12 and 13. The source of pressurized fluid which is connected with he conduits 12 and 13 is not shown in the drawing.

The lower end wall 5a of the metering cylinder 2 is separably connected with a filling head 9. A spindle 10 in the upper end wall 11 of the cylinder 1 serves as a means for adjusting the stroke of the piston 3 and for thereby determining the amounts of propellant which is introduced into successive packages 28.

In accordance with a feature of my invention, the upper end wall 5 of the metering cylinder 2 is provided with an internal annular space 14 which accommodates a supply of lubricant 15, e.g., oil. The lubricant surrounds a portion of the plunger 6 and is prevented from penetrating into the cylinders 1, 2 by two annular sealing devices 17, 18 which are respectively installed in the bottom walls 4 and 5. The material of the sealing devices 17, 18 must be resistant to the chemical influence of propellant. A satisfactory material is a synthetic plastic on the basis of polytetrafluorethylene. It is further desirable to employ sealing devices which are automatically held in requisite sealing engagement with the plunger 6 or to provide means for tightening the sealing devices 17, 18 when necessary.

The plunger 6 is hollow and is provided with one or more openings 16 located close to the piston 3. The drawing shows two openings 16 which are located diametrically opposite each other Such openings permit penetration and evacuation of air which enters the lower chamber of the cylinder 1 by way of the conduit 13. The air cools the plunger 6 to thereby remove some heat which develops on compression of gaseous propellant in the metering chamber 19 of the cylinder 2. Circulation of air into and from the interior of the plunger 6 takes place in automatic response to reciprocation of the piston 3.

The lower end wall 5a of the metering cylinder 2 is provided with an inlet 20a for admission of gaseous or liquefied propellant and with an outlet 20 which can admit propellant to an annular groove 21 in the bottom end face of the cylinder 2 and thence into an inlet 23b of the filling head 9. The outlet 20 is a bore which extends in parallelism with the axis of the cylinder 2. This reduces the volume of dead space between the cylinder 2 and the filling head. The filling head 9 is hollow and accommodates a stressed helical valve spring 22 which biases a small plunger 23 constituting the valve member of the open-and-shut valve in the filling head. The valve member 23 is reciprocable in a cylindrical sleeve 24 of the filling head 9 and its lower end normally bears against a sealing washer 25 installed in the filling head above a normally sealed outlet 23a. The washer 25 overlies an internal annular shoulder of the filling head 9. The lower end portion of the valve member 23 is formed with a recess 26 which can receive the valve 27 of the aerosol package 28. A sealing ring 29 in the outlet 23a of the filling head 9 engages the valve 27 of the package 28 when such valve extends into the recess 26 to thereby seal the propellant from the atmosphere. The exact construction of the filling head 9 forms no part of the present invention; it is preferably designed in such a way that it opens rapidly at a predetermined pressure (e.g., 40 atmospheres superatmospheric pressure) when the apparatus is used for filling of packages 28 with gaseous propellant and closes rapidly in response to a relatively high constant pressure which is equal to or approximates the opening pressure.

The metering cylinder 2 is provided with a hollow cylindrical jacket 30 and the filling head 9 is formed with a second hollow jacket 31. These jackets receive water or other suitable conditioning fluid from a source 32, e.g., a tank, by way of a fluid-circulating device which includes conduits 34, 35 connecting the tank 32 with the jacket 31, a further conduit 36 which connects the jacket 31 with the lower end of the jacket 30, a return conduit 37 which connects the upper end of the jacket 30 with the tank 32, and a pump 33 which is installed between the conduits 34, 35. The apparatus further comprises means for regulating the temperature of conditioning fluid in the tank 32. Such means includes a thermostat 38 which dips into fluid in the tank 32 and controls a valve 41 installed in a conduit 39 which is connected with a water tap or the like. The conduit 39 includes a portion 40 which forms a coil and dips into fluid in the tank 32. The thermostat 38 insures that the water (coolant) which flows through the conduit 39 and its coil 40 maintains the temperature of conditioning fluid in tank 32 at a constant value of within a predetermined range of temperatures. The regulation of temperature of the conditioning fluid is important when the aerosol packages are filled with gaseous propellant, i.e., when some of the compression head must be withdrawn from the metering cylinder 2 and filling head 9. This insures that each of a series of containers 28 receives the same amount of gaseous propellant because the circumstances (as regards the temperature) during filling of successive containers are the same or nearly the same.

The inlet 20a of the metering cylinder 2 is connected with a supply conduit 42 which contains a one-way valve 43 and in connected with the discharge opening of a three-way valve 44. This valve is further connected with a supply conduit 48 which contains a pump 49 and receives liquefied propellant from a source 7. A source 8 of gaseous propellant is connected with the valve 44 by a further supply conduit 45 which contains a pressure reducing valve 47 and includes a portion 46 which forms at least one coil and dips into conditioning fluid and the tank 32. The valve 44 can assume three positions in the first of which it connects the conduits 42, 48, in the second of which it connects the conduits 42, 45, and in the third of which it seals the conduit 42 from the conduits 45, 48. The drawing shows the valve 44 in a position in which it permits flow of gaseous propellant from the conduit 45 into the conduit 42.

The means for moving aerosol packages 28 into and away from engagement with the filling head 9 comprises a platform or table 52 which is connected to the upper end of a rod 53 forming part of a piston 50 in a double-acting hydraulic or pneumatic cylinder 51 mounted at a level below the filling head. The stroke of the piston 50 is selected in such a way that the platform 52 can move the valve 27 of a package 28 into the outlet 23a of the filling head 9 so that the dome of the valve 27 is engaged by the sealing ring 29. It is clear that the package 28 can be supported by a stationary platform and that the parts 1, 2 and 9 can be moved as a unit up and down to thereby move the head 9 into and away from engagement with the stationary package.

The operation:

If a package 28 is to receive a metered amount of liquified propellant from the source 7, the valve 44 is adjusted so that it connects the conduit 42 with the supply conduit 48. The pump 49 then introduces into the metering chamber 19 a predetermined amount of liquefied propellant which is free of bubbles. The conduit 12 thereupon admits pressurized fluid into the upper chamber of the cylinder 1 so that the piston 3 moves away from the spindle 10 and the plunger 6 expels liquefied propellant by way of the outlet 20, groove 21, inlet 23b, outlet 23a and into the interior of the package 28. The magnitude of pressure which is required to move the piston 3 downwardly depends on the ratio of effective surfaces of piston 3 and plunger 6, on the pressure of liquefied propellant in the metering chamber 19, and on the force which holds the valve member 23 of the filling head 9 in closed position. Once the pressure in metering chamber 19 exceeds a predetermined value, the valve member 23 moves to open position (i.e., away from the sealing washer 25). When a package is being filled with liquefied propellant, the pump 33 is idle because the cylinder 2 and filling head 9 require no cooling.

If the apparatus is used for filling of packages 28 with gaseous propellant which is supplied by the source 8, the valve 44 is adjusted to assume the position shown in the drawing and the pump 33 is started to circulate the conditioning fluid from the tank 32, through conduits 34, 35, jacket 31, conduit 36, jacket 30, return conduit 37 and back to the tank 32. The valve 47 is adjusted to insure that the coil 46 receives gaseous propellant at a predetermined pressure and such propellant is cooled to a predetermined temperature while it flows through the coil 46. The propellant then flows through the valves 44, 43, supply conduit 42 and inlet 20a into the metering chamber 19 of the cylinder 2. In contrast to operation during admission of liquefied propellant, the plunger 6 is held in upper end position for a period of time which depends on the pressure of gaseous propellant at the inlet 20a and the pressure required to open the valve member 23 in the filling head 9. The pressure of gas in the metering chamber 19 rises as a result of heating of compressed propellant. When such pressure reaches a given value, the valve member 23 moves away from the washer 25. Propellants in the form of carbon dioxide gas of laughing gas are heated beyond their critical temperature so that it is not necessary to limit their pressure. The temperature of gases which are to be admitted into packages 28 remains above such critical temperature because the interval allotted for filling of a package is very short (e.g., about 1 second) so that the gases cannot exchange too much heat with the adjoining walls of the cylinder 2 and filling head 9. Such heat is withdrawn by conditioning fluid which is circulated by the pump 33.

The pressure of gaseous propellant at the inlet 20a can be varied within a wide range, as long as it does not exceed the pressure which is required to move the valve member 23 away from closed position. As a rule, the pressure which is required to open the valve member 23 exceeds 40 atmospheres superatmospheric pressure; this is desirable to reduce the time which is required to complete the filling of a package 28 with gaseous propellant. The interval which is required for filling of a package can be reduced by increasing the pressure of gaseous propellant during admission into the chamber 19. The amount of gaseous propellant which is admitted into a package 28 is determined by the stroke of the plunger 6, the setting of the pressure reducing valve 47, the temperature of propellant, the volume of dead space in the apparatus, and the pressure required to open the valve member 23. Each package 28 receives only a portion of gaseous propellant which is contained in the apparatus during filling. This is in contrast to operation with liquefied propellant.

It is further desirable to provide the tank 32 with means for rapidly heating the conditioning fluid to a desired temperature when the apparatus is started. Such means may include a source of hot water and a second regulating unit which is similar to the unit including the parts 38-41 with the exception that its bimetallic thermostat regulates the circulation of hot water. This enables the operator to rapidly raise the temperature of conditioning fluid to an optimum value when the apparatus is started.

When the plunger 6 completes its downward stroke during expulsion of gaseous propellant from the metering chamber 19, and when the pressure in the filling head 9 decreases to a value at which the valve member 23 returns to closed position, the apparatus admits pressurized fluid into the lower chamber of the cylinder 1 so that the piston 3 returns into abutment with the spindle 10. The package 28 on the platform 52 is then disengaged from the filling head 9 and replaced with a fresh package. It is desirable to select a filling head which is designed in such a way that the valve member 23 opens and closes in response to a predetermined pressure; this insures that each of a succession of packages 28 receives the same amount of gaseous propellant.

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 which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

Claims

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In an apparatus for filling aerosol packages with gaseous and liquefied propellants, a combination comprising a metering cylinder defining a metering chamber having propellant-admitting and propellant-evacuating inlet and outlet means; a hollow plunger reciprocably received in said chamber, said cylinder further defining a lubricant-containing annular space surrounding a portion of said plunger and sealed from said metering chamber: drive means for reciprocating said plunger; a filling head connected with said cylinder and having an inlet in communication with said outlet means and a normally sealed outlet, said filling head and said cylinder having hollow jackets; a source of conditioning fluid; means for circulating conditioning fluid from said source and through said jackets; a source of gaseous propellant; supply conduit means connecting said propellant source with said inlet means, pressure-reducing valve means provided in said conduit means; and one-way valve means provided in said conduit means between said pressure-reducing valve means and said inlet means, said conduit means comprising a portion extending intermediate said pressure-reducing valve means and said one-way valve means and dipping into conditioning fluid in said first mentioned source.

2. A combination as defined in claim 1 wherein said portion of the supply conduit means forms at least one coil.

3. In an apparatus for filling aerosol packages with gaseous or liquid propellants, a combination comprising a metering cylinder having an end wall and defining a metering chamber having propellant-admitting inlet means and propellant-evacuating outlet means; a hollow internally cooled plunger extending into said cylinder and reciprocable therein to thereby change the volume of said metering chamber, said end wall of said cylinder sealingly surrounding said plunger and defining a lubricant-containing annular space which surrounds a portion of said plunger and is sealed from said metering chamber; drive means for reciprocating said plunger; a filling head connected with said cylinder and having an inlet in communication with said outlet means and a normally sealed outlet, said filling head and said cylinder having hollow jackets; a first source containing a supply of a conditioning fluid; means for circulating the conditioning fluid from said source and through said jackets; a second source containing a supply of a gaseous propellant; supply conduit means connecting said second source with said inlet means; pressure reducing valve means provided in said conduit means; and one-way valve means provided in said conduit means between said pressure-reducing valve means and said inlet means.

4. In an apparatus for filling aerosol packages with gaseous or liquid propellants, a combination comprising a metering cylinder having an end wall and defining a metering chamber having propellant-admitting inlet means and propellant-evacuating outlet means; a hollow internally cooled plunger extending into said cylinder and reciprocable therein to thereby change the volume of said metering chamber, said end wall of said cylinder sealingly surrounding said plunger and defining a lubricant-containing annular space which surrounds a portion of said plunger and is sealed from said metering chamber; drive means for reciprocating said plunger; a filling head connected with said cylinder and having an inlet in communication with said outlet means and a normally sealed outlet, said filling head and said cylinder having hollow jackets; a first source containing a supply of a conditioning fluid; means for circulating the conditioning fluid from said source and through said jackets; a second source containing a supply of a liquefied propellant; and supply conduit means connecting said second source with said inlet means.

5. A combination as defined in claim 4, further comprising pump means provided in said supply conduit means and operative to deliver liquefied propellant from said second source to aid inlet means.

6. A combination as defined in claim 5, further comprising one-way valve means provided in said conduit means between said pump means and inlet means.

7. In an apparatus for filling aerosol packages with gaseous or liquid propellants, a combination comprising a metering cylinder having an end wall and defining a metering chamber having propellant-admitting inlet means and propellant-evacuating outlet means; a hollow internally cooled plunger extending into said cylinder and reciprocable therein to thereby change the volume of said metering chamber, said end wall of said cylinder sealingly surrounding said plunger and defining a lubricant-containing annular space which surrounds a portion of said plunger and is sealed from said metering chamber; drive means for reciprocating said plunger; a filling head connected with said cylinder and having an inlet in communication with said outlet means and a normally sealed outlet, said filling head and said cylinder having hollow jackets; a first source containing a supply of a conditioning fluid; means for circulating the conditioning fluid from said source and through said jackets; a second source containing a supply of a liquefied propellant; a third source containing a supply of gaseous propellant; first conduit means connected with said inlet means; second conduit means connected with said second source; third conduit means connected with said third source; and valve means connected with said conduit means and movable between a plurality of positions in one of which said first conduit means is connected with said second conduit means and in another of which said first conduit means is connected with said third conduit means.

8. A combination as defined in claim 7, further comprising one-way valve means provided in said first conduit means, pump means provided in said second conduit means, a pressure-reducing valve means provided in said third conduit means.

9. In an apparatus for filling aerosol packages with fluid propellants, a combination comprising a metering cylinder having an end wall and defining a metering chamber having propellant-admitting inlet means and propellant-evacuating outlet means; a hollow internally cooled plunger extending into said cylinder and reciprocable therein to thereby change the volume of said metering chamber, said end wall of said cylinder sealingly surrounding said plunger and defining a lubricant-containing annular space which surrounds a portion of said plunger and is sealed from said metering chamber; drive means for reciprocating said plunger; a filling head connected with said cylinder and having an inlet in communication with said outlet means and a normally sealed outlet, said filling head and said cylinder having hollow jackets; a first source containing a supply of a fluid-conditioning medium; means for circulating the conditioning medium from said first source and through said jackets; a second source containing a supply of a fluid propellant; and supply conduit means connecting said second source with said inlet means.

10. A combination as defined in claim 9, wherein said cylinder further comprises a record end wall which is connected with said filling head and is provided with said outlet means.

11. A combination as defined in claim 9, further comprising means for regulating the temperature of conditioning medium said first source.

12. A combination as defined in claim 11, wherein said regulating means comprises thermostat means.

13. A combination as defined in claim 9, wherein said drive means comprises a cylinder and piston unit whose piston is rigid with said hollow plunger.

14. A combination as defined in claim 9, further comprising a pair of annular sealing devices surrounding said plunger at the opposite axial ends of said lubricant-containing space.

15. A combination as defined in claim 14, wherein said drive means comprises a second cylinder and a piston reciprocable in said second cylinder and connected with said plunger, said second cylinder having an end wall adjacent to the end wall of said metering cylinder and each of said end walls accommodating one of said sealing devices.

16. A combination as defined in claim 9, wherein said drive means comprises a second cylinder separably secured to said end wall of said metering cylinder, said metering cylinder having another end wall separably secured to said filling head.

17. A combination as defined in claim 9, wherein said means for circulating the conditioning medium comprises second conduit means connecting the interior of one of said jackets with the interior of the other jacket.

18. A combination as defined in claim 17, wherein said means for circulating the conditioning medium further comprises third conduit means for delivering the conditioning medium from said first source to one of said jackets and fourth conduit means for returning the conditioning medium from the other jacket to said first source.

19. A combination as defined in claim 9, wherein said metering cylinder comprises a second end wall which is connected with said filling head and wherein the outlet means of said metering cylinder is parallel to the axis of the metering cylinder.

20. A combination as defined in claim 9, wherein said drive means comprises a fluid-operated cylinder and piston unit whose piston is rigid with said plunger, said plunger having at least one opening establishing communication between the interior of the cylinder of said unit and the interior of said plunger whereby the fluid which operates said unit can circulate between the interior of said plunger and the interior of the cylinder of said unit to internally cool the plunger.

21. A combination as defined in claim 20, wherein said opening is closely adjacent to the piston of said unit.