US3055402A - Filling of pressurized containers with liquids of low boiling point - Google Patents

Description

p 1952 H. P. SCHOFIELD 3,055,402

FILLINGOF PRESSURIZED CONTAINERS WITH LIQUIDS 0F LOW BOILING POINT Filed April 15, 1959 2 Sheets-Sheet 1 mvzmon" M10417 Rims-mm ATTORNEY Sept. 25, 1962 H. P. SCHOFIELD 3,055,402 FILLING OF PRESSURIZED CONTAINERS WITH LIQUIDS OF LOW BOILING POINT Filed April 15. 1959 2 Sheets-Sheet 2 ATTORNEY The present invention relates to the filling of pressurized bottles, canisters, cans or other containers including, for example, those of the type known as aerosols and others such as fire-extinguishers, gas cigarette lighters and portable heaters.

In general practice, pressurized containers of the type referred to are filled under refrigerating conditions so as to prevent vaporizing of the propellant liquid which is to be added to the product within the containers for subse quent ejection thereof. However, this involves high capital outlay and difiicult and unpleasant working conditions. Occasionally pressure filling of the propellant liquid is employed, and the approximate volume of propellant used is estimated by the pressure reached in the container, but this requires compensation for variations in ambient temperatures. In filling containers by present methods, the successive operations of filling with the product and the propellant generally take place at different times and, where these operations are also performed in different rooms or at difierent localities, transport is involved.

The object of the present invention is to enable the filling operation with both the product and the propellant to be performed under normal conditions of varying ambient temperature and to a consistently high degree of accuracy and with only one handling of the container.

In apparatus for the filling of pressurized containers according to the present invention, means are provided which, on establishing connection between an inlet orifice of the container and a nozzle of a charging head of the apparatus, initiate the communication between said inlet and a vacuum source, a product metering device, and a propellant metering device either separately or selectively in any two-stage or three-stage sequence consistent with a predetermined setting of control means associated with said vacuum source and said metering devices.

Where the product to be ejected from the containers may itself be utilized as the propellant, such as, for example, in the case of fire-extinguishers using carbon tetrachloride, a two-stage operation is performed in accordance with the invention, which consists of the applica- .tion of a predetermined degree of vacuum to the container and the filling thereof with the requiredproduct acting also as the propellant. If there is no disadvantage in having air under pressure within the container, it will be appreciated that a single stage operation is all that is required.

Where, however, the propellant is a different medium than the product and the pressure of oxygen is undesirable, three stages are involved, namely the application of a predetermined degree of vacuum, the insertion of a predetermined volume of the product and the insertion of a predetermined volume of the propellant. The insertion of the product may precede that of the propellant or follow it as desired, while the predetermined degree of vacuum may be applied initially or as the second stage between either the insertion of the product and the propellant or the insertion of the propellant and the product, as the case may be.

Further, if desired, the vacuumizing means, or the product or the propellant supply means may be energized simultaneously with the termination of the act of placing each container in position on or in the charging head.

3,055,402 Fatenteci: Sept. 25, 1962 In a convenient form of construction consistent with the present invention a container to be filled is placed on a vertically displaceable platform which is adapted to be automatically raised to bring the inlet of the container into operative engagement with a stationary nozzle by electric, pneumatic, hydraulic, or other means energized by each container itself when it reaches a predetermined position on the platform. The sealing of a container inlet by the nozzle in turn automatically energizes the vacuumizing means and the product and propellant supply means consistent with the predetermined setting of vthe device to meet particular container loading requirements.

The invention is more particularly described with reference to the accompanying drawings which illustrate one embodiment thereof merely by way of example. In the drawings:

FIGURE 1 is a diagrammatic representation of ageneral arrangement of the apparatus and FIGURE 2 is a wiring diagram.

Referring to FIG. 1 in detail, it will be seen that the apparatus includes a charging head capable of conducting three operations in a predetermined order on each of a number of canisters or other containers C supplied in succession to the apparatus. The charging head embodies a dispensing valve assembly 10 consisting of three solenoid operated valves 11, 12 and 13, respectively. The valve 11 controls a vacuum line 14 from a vacuum source 15 to the valve assembly 10. The valve12 con- 7 trols the supply of the product from a source 16, through a metering cylinder 17 and pipe line 18. The valve 13 controls the supply of a propellant from a source represented at 19 through a metering cylinder and a pipe line 241. The valves 11, 12, 13 are normally urged towards their closed positions by spring means.

A solenoid controlled valve 22 and a vacuum sensitive micro-switch 23 are located in the pipe 14 which is shown in full lines. In the pipe line 18 shown in broken lines and extending from the product supply source 16 to the valve 12, there is located a two-position, four-way valve 24, the through passages in one position being shown in full lines and the through passages in the alternative positionbeing shown in dotted lines. In the formerposition, the line from the valve 24 leads to the left hand end of the metering cylinder 17 while the opposite end of said cylinder is connected to the valve 12, and, in the alternative position of the valve. 24, the source'16 is in communication with the right hand end of the cylinder 17 and the product flows from the left hand end of cylinder 17 to said valve 12. Solenoids 25, 125 are adapted to oppositely displace an arm 26 for the purpose of rotating the valve 24 through an angle of between the two above described positions of the valve.

Similarly, the pipe line 21 includes a two-position, four-way valve 27 for alternatively establishing communication between one end of the metering cylinder 20 and the propellant supply source 19 whilethe other end of the cylinder is in communication with the'valve 13, and between that other end of cylinderZtl and source 19 while the first mentioned end of the cylinder is in piston 30 or 31 to a predetermined .extent to effect delivery from the other end of the cylinder to the appropriate valvelZ or'13 of a predetermined volume of product or propellant. The delivered volume: of. product 3 or propellant is wholly independent of ambient temperature.

The limits of the displacement of the piston 30, in one direction, is controlled by a combined micro-switch and mechanical stop member 32 and, in the other direction, by an adjustable combined micro-switch and mechanical stop member 33. Thus, the delivered volume of liquid resulting from each stroke of the piston 30 in response to operation of the valve 24 may be infinitely varied by changing setting of the member 33. Similarly, the displacement of the piston 31 may be controlled by a fixed combined micro-switch and stop member 34 and a combined micro-switch and mechanical stop member 35 which is infinitely adjustable between any of the extreme positions shown respectively in full and dotted lines.

A recess 36 is formed in the charging head, and a vertically displaceable platform 37 is detachably mounted on a shaft 38 projecting upwardly from the head into the recess 36. A locating element 39 is provided at the rear of the recess 36 above the platform. The locating element operates as a trigger for energising the required means for elevating the platform 37 when a container is placed on the latter and pushed towards the rear of the platform to act against the locating element 39 so as to displace the latter.

In the construction consistent with the diagrammatic representation of FIGURE 1, the locating element 39 and the appropriate switch of the pair 32, 33 and of the pair 34, 35 into the electric circuit for the next cycle, while leaving disconnected those switches which were responsible for the completed cycle.

The various components are mounted on a chassis 48 (FIG. 1) which is housed within, or forms the frame of, afcover or casing having the recess 36 at the front there- 0 In considering a sequence of operations on each container C it will be understood that the reference numeral 16 constitutes an inlet to the apparatus from a source of supply of the liquid product at a suitable pressure, which may for example be as low as say lbs. per square inch or as high as 2,000 lbs. per square inch. Similarly reference numeral 19 represents the connection to a source of supply of propellant at equally widely is in the form of a V-shaped member which is adapted for contact with a micro-switch 40 interposed in the electrical energizing circuit for a solenoid 41. When solenoid 41 is energized, it raises the platform and the container to eifect a seal between the inlet of the container and a nozzle 42 located in the ceiling of the recess 36 of the charging head. However, the platform 37 may be raised hydraulically, pneumatically or by the application of vacuum in any well known manner. It may also be lowered by any desired means (not shown).

In general the valves 11, 12, 13 work independently and in a correct sequence. The discharge point or nozzle 42 is arranged, in relation to the height of the interchangeable platform 37 and the location of the V-shaped by gravity, by a spring, or electrically, hydraulically or pneumatically or any other means.

An adjustable striker arm 43 is mounted on the shaft 38 so as to contact a micro-switch 44 when the interchangeable platform 37 reaches that position at which the valve at the orifice of the container C is opened by the nozzle 42. The micro-switches 40, 44 act also as mechanical stop members.

Referring now to FIG. 2, it will be seen that, in the electrical circuit of the apparatus shown in FIG. 1, all of the micro-switches with the exception of the micro-switch 40 carry both normally-closed and independent normallyopen contacts. In the drawings they are shown in the spring loaded rest position. The contacts of these microswitches all reverse upon the triggering of the switch.

An automatic change-over relay or switch 45 incorporating two coils 46, 47 is included in the electrical circuit, one coil 46 being in the circuit of the solenoids 25,

28 and the other coil 47 in the circuit of the solenoids 125, 128.

The coils 46 and 47 are alternatively connected in the electrical circuit by the switches 32 and 33 and selectively operate alternative sets of changeover contacts which, at the end of a cycle of operations, puts the opposite sides of the dual solenoids 25, 125 and 28, 128

different pressures. The electrical source is omitted from FIGURE 2 for the sake of clarity as are the change-over wiring and contacts for ensuing disconnection of some micro-switches simultaneously with others being energised. The various supporting brackets for the different components, such as the metering cylinders 17, 20, are also omitted for the same reason.

A can, canister, bottle or other container to be filled, which is diagrammatically represented at C, is placed on the platform 37 and pushed back against the V-shaped forward end of the arm 39 to retract the latter and thereby contact the micro-switch 40 which also acts as a mechanical stop to locate the container C in the required vertical alignment with the nozzle 42 of the valve assembly 10. Contact of switch 40 initiates a complete cycle of operations by energizing the solenoid 41 through the normally closed contacts of switches 44 and 32 to cause the shaft 38 and platform 37 to rise until the valve controlled orifice (not shown) of the container C nests satisfactorily in sealed relationship with the nozzle 42.

' Simultaneously with this the arm 43 of the shaft 38 comes into contact with the micro-switch 44 which acts as a mechanical stop to prevent any undue elevation of the platform 37 which might tend to damage the container C.

Triggering of the micro-switch 44 automatically opens the valves 22 and 11 [in the vacuum line 14 so that a predetermined degree of vacuum is created within the container C. When this predetermined degree of vacuum has been achieved, the switch 23 is automatically operated to cause the valves 22 and 11 to close and to eflect opening of the valve 12'.

At the instant of opening of the valve 12, the four-way valve 24 is in the correct position for the necessary pressure supply of liquid product to the metering cylinder 17 7 so as to move the freely floating piston 30 thereof and discharge a measured dose of product to the container via the pipe line 18, the valve 12 and the nozzle 42. The volume of product in such dose is determined by the positions of the micro-switches 32, 33 which limit the displacement of the piston 30. According to the direction of displacement of the Piston 30 in discharging this measured dose, one or other of micro-switches 32, 33 will be triggered at the end of said displacement to displace the fourway valve 24 through and also close the valve 12. Such displacement of the valve 24 is, of course, achieved by the solenoid 25 or the solenoid according to the direction of displacement of the piston and the particular micro-switch 32 or 33 which has been actuated. However, the arrangement is such that, When the valve 12 is re-opened during the next sequence of operations on a pipe line21, the valve 13 and the nozzle 42 to the container C. Operation either of the micro-switch 34 or 35 at the end of the stroke of the piston 31 energizes the solenoid 28 or the solenoid 128 to displace the four-way valve '27 to its alternative position so as to enable a similar dose of propellant to be inserted in the next succeeding container at the appropriate stage in the next complete cycle of operations.

The appropriate micro-switch 34, 35 acted upon at the end of the stroke of the piston 31 also operates to close the valve'13 and thus the nozzle 42 and also to cut otf or to reverse the supply of current to the solenoid41. The solenoid 41 then permits the shaft 38 and the platform 37 to descend, so that the filled container C may be withdrawn andthe apparatus is ready to take another empty container for repetition of a similar complete cycle of operations.

Itwill be appreciated that in one complete cycle of operations the left-hand micro-switches 32, 34 and the solenoids 25, 28 are actively engaged and energized at appropriate parts of the cycle, while, during the next cycle of operations on a succeeding container C the right-hand micro-switches 33, 35 and the solenoids 125, 128 perform their required operations at the appropriate times.

It will also be appreciated that, by Virtue of the fact that the piston 30 or 31 in the metering cylinder 17 or 20 is of the freely floating type and serves solely for metering, as distinct from liquid displacement purposes, any leakage which occurs between one side of the piston and the other has no efiect on the quantity of liquid delivered during each piston stroke. Thus with apparatus embodying the present invention, a delivery accuracy in the region of 99.5% can be maintained. This is in favorable contrast to the accuracy achieved when a measured volume of liquid is inserted into a cylinder and then delivered therefrom by the hydraulic or other displacement of its piston. In the above arrangement, a number of factors, such as, the speed of displacement of the piston, the abruptness of starting and stopping of the piston, the load on the piston .and the wear thereof leading to leakage between the piston and the cylinder walls combine to render it impossible to maintain a delivery accuracy greater than 95.0%

Numerous modifications may be adopted without departing from the invention and its scope. Thus a switch (not shown) may be incorporated in each of the three circuits to enable any circuit to be cut out, when desired, without interfering with the starting and stopping of the apparatus on initiating and completing a predetermined sequence.

For the purpose of simplifying the structure, the triggering operations of the micro-switches may be effected by an intermediate mechanism which may be in the form of a bank of cams having a series of positions consistent with the cycle of operations to be performed. Thus, instead of eifecting the triggering operations directly by the micro-switches referred to herein, these triggering operations may be achieved indirectly by the sequence control device described in the provisional specification of UK. patent application No. 34,665/ 1958.

I claim:

1. Apparatus for filling pressurized containers; comprising a charging head having a nozzle adapted for connection to the inlet orifice of a container to be filled, a source of vacuum and at least first and second sources of fluids under pressure, said head having a passage extending to said nozzle for each of said sources, a shut-ofi valve means for closing each of said passages, conduit means connecting said source of vacuum with the related passage of said head, a metering cylinder for each source of fluid under pressure, a piston movable axially in said cyilnder,

reversing valve means for each metering cylinder, conduit means extending from said reversing valve means to the related source of fluid under pressure, to the related passage of said head and to the opposite ends of the metering cylinder, said reversing valve means having a first operative position in which one end of said cylinder is communicated with the related source of fluid under pressure while the other end of the cylinder is communicated with the related passage of said head and a second operative position in which said related passage of the head and said source of fluid under pressure are respectively communicated with said one end and said other end of the cylinder, actuating means for each reversing valve means operative to dispose the latter alternatively in said first and second operative positions, and sequence control means including means operative to initially open the shut-off valve means associated with the passage of said head connected to said source of vacuum, means operative to close said shut-01f valve means of the vacuum passage when a predetermined vacuum is attained in a container to be filled having its inlet orifice connected to said nozzle and to open the shut-off valve means of the passage for the first source of fluid under pressure so that fluid from said first source is discharged from an end of the related metering cylinder while fluid under pressure is admitted from said first source to the opposite end of said metering cylinder to displace said piston in the latter, and means responsive to a predetermined displacement of said piston to close said shut-off valve means of the fluid supply passage for the first source of fluid, to operate said actuating means for the related reversing valve means and to open the shutoff valve means of the passage for the second source of fluid under pressure so that fluid from said second source is discharged from an end of the related metering cylinder while fluid under pressure is admitted from said second source to the opposite end of the related metering cylinder to displace the piston in the latter, and means responsive to a predetermined displacement of the piston in the metering cylinder associated with said second source to close the related shut-0E valve means and to operate the actuating means for the related reversing valve means.

2. Apparatus for filling pressurized containers; comprising a charging head having a nozzle adapted for connection to the inlet orifice of a container to be filled, a source of vacuum, a propellant source and -a liquid prod uct source, said head having passages communicating with said nozzle for the vacuum, propellant and product, respectively, and shut-off valve means for each of said passages, conduit means connecting said source of vacuum to said vacuum passage of the head, a metering cylinder for the propellant, a metering cylinder for the product, each of said metering cylinders having a piston movable axially therein, reversing valve means for each metering cylinder, conduit means extending from each reversing valve means to the related source and the related passage of said head and to the opposite ends of the related metering cylinder, each reversing valve means having a first operative position in which one end of the related metering cylinder is connected to the related source and the opposite end of the related cylinder is connected to the related passage of said head, and a second operative position in which said related passage and source are respectively connected to said one end and said opposite end of said related metering cylinder, actuating means for each reversing valve means operative to dispose the latter alternatively in said first and second operative positions, and sequence control means including means operative to initially open said shut-off valve means of the vacuum passage upon the connection of said nozzle to the inlet orifice of a container to be filled, means operative to close said shutoff valve means of the vacuum passage when a predetermined vacuum is attained in the container to be filled and to open the shut-01f valve means of the product passage so that liquid product is discharged from an end of the related metering cylinder while liquid product under pressure is supplied from the source thereof to the opposite end of the cylinder to displace said piston in the latter, means responsive to a predetermined displacement of the piston in the metering cylinder for the liquid product to close said shut-off valve means of the product passage and open said shut-off valve means of the propellant pasage, and to operate said actuating means for the reversing valve means associated with the product metering cylinder, and means responsive to a predetermined displacement of the piston in the metering cylinder for the propellant to close said shut-off valve means of the propellant passage and to operate said actuating means for the reversing valve means associated with the propellant metering cylinder.

3. Apparatus as in claim 2; wherein each of said means responsive to a predetermined displacement of the piston in the metering cylinder includes mechanical stop members adjustable parallel to the axis of the related metering cylinder and operative to limit the displacement of the piston in the latter in opposite directions, and microswitches carried by said stop members and actuated upon the displacement of the related piston to the limit permitted by the related stop member.

4. Apparatus for filling pressurized containers; comprising a charging head having a downwardly projecting nozzle adapted for connection to the inlet orifice of a container to be filled, a vertically movable platform disposed below said nozzle and adapted to support a container to be filled, means responsive to the positioning of a container on said platform to effect upward movement of the latter so as to connect said nozzle with the inlet orifice of the container, a source of vacuum, conduit means connecting said source to said nozzle and having first and second valves in series therein, means opening said first and second Valves in response to a predetermined upward movement of said platform, pressure responsive means closing said second valve upon the attainment of a predetermined vacuum in a container connected to said nozzle, at least one source of a fluid under pressure, a metering cylinder for each source of a fluid under pressure and having a piston movable axially therein, reversing valve means for each metering cylinder, conduit means connecting said reversing valve means to the related source and said nozzle and to the opposite ends of the related metering cylinder, said reversing valve means having a first operative position in which said source of fluid and said nozzle are connected to the opposite ends of said metering cylinder by way of said reversing valve means, and a second operative position in which the connections of said source of fluid and nozzle to the opposite ends of the metering cylinder are reversed, actuating means for said reversing valve means operative to dispose the latter alternatively in said first and second operative positions, a shut-off valve in said conduit means between said reversing valve means and said nozzle, means opening said shut-off valve upon the closing of said second valve by said pressure responsive means so that the fluid under pressure admitted to one end of said metering cylinder then displaces said piston in the latter to discharge the fiuid from the opposite end of the metering cylinder to said nozzle, control meansresponsive to a predetermined displacement of said piston to close said shut-otf valve and to operate said actuating means for the reversing valve means, a second source of fluid under pressure constituting a propellant and having associated therewith a second metering cylinder with a piston movable axially therein, a second reversing valve means with a corresponding second actuating means therefor, conduit means connecting said second source and nozzle to said second reversing valve means and connecting the latter to the opposite ends of said second metering cylinder, and a second shut-off valve in said conduit means between said second reversing valve means and said nozzle, said control means responsive to displacement of the piston of the first mentioned metering cylinder also causing opening of said second shut-off valve so that the propellant then admitted to said second metering cylinder causes displacement of the piston in the latter to efiect discharge from said second metering cylinder to the nozzle of the propellant previously admitted to the second cylinder, and second control means responsive to a predetermined displacement of the piston in said second metering cylinder to close said second shut-off valve and to operate said second ac- 1 tuating means, whereby metered quantities of the liquid ment of said piston rods and being adjustable parallel to said paths of movement for varying the lengths of the operating strokes of said piston, and micro-switches carried by said stop members and actuated by said piston rods at the ends of the operating strokes of the related piston.

References Cited in the file of this patent UNITED STATES PATENTS 2,518,064 Rapisarda Aug. 8, 1950 2,536,300 Martin Ian. 2, 1951 2,661,885 McBean Dec. 8, 1953 2,882,999 Morgan Apr. 21, 1959

Images