US3750367A - Web sterilizing system - Google Patents

Abstract

A form-fill-seal type of packaging machine in which a pair of rolls of plastic are used in respectively forming and sealing containers is provided with a pair of utilization tanks through which the two webs of plastic material are fed in order to sterilize the webs or sheets due to contact with a sterilizing liquid such as hydrogen peroxide contained in the two tanks. Should the machine be shut down either deliberately or by inadvertence for any reason, the germicidal agent may affect the plastic material immersed therein in an adverse manner. Thus means are provided for draining the germicidal liquid from the utilization tanks into a reservoir tank thereby to preclude any possible undesired effects by controlling suitable valves in the supply and return conduits or by other means.

Description

United States Patent 1 Barker et al.

[ 1 Aug. 7, 1973 1 WEB STERlLlZlNG SYSTEM [75] lnventors: Charles J. Barker, Atlanta; John H.

Perry, Doraville, both of Ga.

[22] Filed: Mar. 28, 1972 [21] Appl. No.: 238,872

Primary ExaminerAndrew R. Juhasz Assistant Examiner-W. D. Bray Attorney-Walter M. Rodgers [5 7 ABSTRACT A form-fill-seal type of packaging machine in which a pair of rolls of plastic are used in respectively forming and sealing containers is provided with a pair of utilization tanks through which the two webs of plastic material are fed in order to sterilize the webs or sheets due to contact with a sterilizing liquid such as hydrogen peroxide contained in the two tanks. Should the machine be shut down either deliberately or by inadvertence for any reason, the germicidal agent may affect the plastic material immersed therein in an adverse manner. Thus means are provided for draining the germicidal liquid from the utilization tanks into a reservoir tank thereby to preclude any possible undesired effects by controlling suitable valves in the supply and return conduits or by other means.

6 Claims, 4 Drawing Figures PATENIEU 7 I975 FIG. 1B

SHEET 10F 2 FIG! PATENTED AUG 7 I975 SHEEI 2 0f 2 N GE WEB STERILIZING SYSTEM Packages formed, filled and sealed must be germ free when the package contents are of such nature that germicidal action renders the contents unfit for use after a short period of time following sealing of such packages. It is thus necessary to eliminate all bacteria from the materials from which such packages are formed and sealed and to maintain these elements in a germ free condition. Ordinarily the body portion of such containers is formed from one sheet of material such as plastic and the cover or lid of such containers is formed from another roll of material such as plastic or the like material. In order to effect the necessary germicidal action, both sheets must be rendered germ free before the packaging operations are initiated and preferably each sheet is passed through a tank'containing a germicidal liquid.

In order to maintain the proper liquid level in both tanks through which the plastic strips are fed and in addition to drain both tanks quickly should the machine be stopped for any reason, each tank is supplied from a reservoir through a suitable common pump and through individual supply conduits and supply valves which are normally open and the level of liquid in both tanks is determined by an overflow conduit which drains into the reservoir tank and which is interconnected with its associated utilization tank at a level controlling the desired level of liquid. in such tank. For proper germicidal action the temperature of the liquid preferably should be controlled and maintained at a level above ambient temperature. To this end the liquid is heated and the liquid flow is controlled so that the desired temperature is maintained in the utilization tanks. In order to drain the tanks quickly if desired and according to one form of the invention, drain conduits and normally closed drain valves are interconnected with the inlet of the pump and the outlet of the pump is connected with the reservoir tank through a return conduit and a normally closed return valve which is opened during the draining operation, so that the pump facilitates draining of the tanks. The supply valves are closed while the two tanss are being drained. If desired the utilization tanks can be drainedquickly by simply reversing the flow of liquid by means of a reversible pump.

For a better understandng of the invention, reference may be had to the following detailed description taken in conjunction .with the accompanying drawings in which FIG. 1 is a generally schematic side view of a form fill seal machine to which the web sterilizing system constructed according to this invention is applicable;

FIG. 1A is a perspective view of one utilization tank;

FIG. 1B is a perspective view of the other utilization tank;

FIG. 2 is a schematic diagramatic representation of the conduits, tanks, valves and pumps which constitute parts of this invention.

In FIG. I the numeral 1 generally designates a roll of plastic material which is utilized in forming the body portion of containers such as cups or the like while thenumeral 2 generally designates a roll of plastic material which forms the cover portion or lid of cups formed from sheet 1.

Roll 1 is mounted on a horizontal shaft designated by the numeral 3 which is supported by horizontal frame elements designated by the numeral 4 together with a pair of vertical pedestals designated by the numeral 5, only one horizontal member 4 and one vertical member 5 being visible in FIG. 1. A generally arcuateshaped tank 6 is supported on horizontal support elements 4 and is filled with a suitable germicidal liquid such as hydrogen peroxide through which the sheet S1 from roll or web 1 is fed.

The numeral 7 generally designates heater units under which the sheet S1 is fed, the feeding operation being facilitated and the drying thereof being enhanced by a pair of rollers designated by the numrral 8. If hydrogen peroxide is used as the germicidal agent, its decomposition into water and nascent oxygen and then into oxygen is facilitated by heaters 7. Sheet S1 is fed from heaters 7 and rollers 8 into a forming press generally designated by the numeral 9. This press is provided with relatively movable dies which form a plurality of cups from the sheet S1.

After the cups are formed they are fed while still interconnected across their upper edge portions'by the web of sheet S1 into a filler station generally designated by the numeral 10 where the cups are filled. Upon completion of the filling operation, the cups are fed while still under aseptic conditions and enclosed within a suitable housing structure 1 1 into a sealing press generally designated by the numeral 12 where the covers or lids are applied to the cups. Upon completion of the sealing operation, the cups are severed one from another about their top edges at the cutting station generally designated by thenumeral 13. The sealed and sev ered individual cups are then complete and are ready for secondary packaging operations if desired by means other than the machine elements depicted schemati cally in FIG. 1.

The sheet S2 supplied fromroll 2 of course must be germ free and toward this end sheet S2 is fed through autilization tank 14 which is filled with a germicidal liquid such for example as hydrogen peroxide. Sheet S2 if fed over rollers 15-20 and past heating elements not shown to the sealing press 12 where it is sealed by known means to the cups formed from sheet S1, roller 17 being immersed withintank 14 which may be configured substantially as shown. The web S2 is fed from its outlet intank 14 thorugh a closed housing (not shown in detail in the drawings) to the sealing press 12 thereby to maintan web 82 under aseptic conditions.

According to this invention,utilization tanks 6 and 14 are supplied with heated germicidal liquid such as hydrogen peroxide from a reservoir tank such as is designated in FIG. 2 by the letter R and the liquid level in theutilization tanks 6 and 14 is maintained at a desired maximum by means of overflow conduits which are interconnected with the utilization tanks through suitable ports the level of which determines the liquid level within the utilization tanks. Furthermore and in accordance with a feature of this invention, theutilization tanks 6 and 14 are quickly drained by the supply pump P either by means of valve action and drain pipes or by reversing the pump. The liquid may be heated in the reservoir tank by known thermostatically controlled heating elements.

With reference to FIG. 2,utilization tank 6 is supplied with liquid by asupply conduit 21 in whichsupply valve 22 is disposed, this valve being normally open so that during operation of centrifugal pump P, liquid is supplied from tank R throughconduit 21,supply valve 22 and manually controlled regulatingvalve 23 toutilization tank 6. Of course the rate of flow of fluid throughsupply conduit 21 must be such as to maintain the level of liquid inutilization tank 6 at least to the level ofoutlet ports 24 and 25 formed at oppositely disposed points inutilization tank 6.Overflow conduit 26 is interconnected withports 24 and 25 and as indicated by the arrow conducts excess liquid inutilization tank 6 back to reservoir tank R and in this manner maintains the desired level of liquid inutilization tank 6.

If the machine such as that shown in FIG. 1 is shut down for any reason, the germicidal liquid withinutilization tank 6 may adversely affect the material comprising sheet S1 and should be drained quickly to prevent damage to S1. Toward this end, adrain conduit 27 and a normally closeddrain valve 28 are provided and serve to interconnect theinlet 29 of pump P and theutilization tank 6, such connection being made through normally open manually controllable regulatingvalve 23 and a portion ofsupply conduit 21 together with a return conduit 3 whih interconnects theoutlet 31 of pump P through a normally closedreturn valve 32 with the reservoir tank R.

In order to draintank 6, normallyopen supply valve 22 is closed and normally closeddrain valve 28 is opened and normally closedreturn valve 32 is opened. Under these conditions operation of the pump P draws liquid fromtank 6 through regulatingvalve 23 and the associated portion ofconduit 21, throughopen drain valve 28, drain conduit 27 through theinlet 29 of pump P from whence the liquid is driven through the now openedreturn valve 32 and its associatedconduit 30 to the reservoir R. Such operation drains thetank 6 quickly because the volume ow liquid within that tank is not great and because the capacity of pump P is appropriately chosen to accomplish this result.

As is apparent in FIGS. 1A and 2,tank 6 is formed of abottom wall 33 which is arcuate in configuration with the mid-portion 34 thereof bowed downwardly and with theside edges 35 and 36 extending upwardly.Top wall 37 is similarly configured and the end edges ofwalls 33 and 37 are closed byend plates 38 only one of which is observable in FIG. 2. Syitable guides not shown preferably are disposed along the inside surface ofwall 37 and serve to space web 81 therefrom.

Tank 6 as shown in FIGS. 1 and 1A is generally J- shaped with the longer prong atoutlet edge 36 in closed communication with housing structure 11 thereby to maintain web S1 under aseptic conditions.

With reference to FIG. 1, it is apparent that roll 1 is conveniently mounted on horizontal supports 4 and may be disposed partially within the recess defined by the downwardly bowedtop wall 37 oftank 6.

For the purpose of supply germicidal liquid toutilization tank 14 and for maintaining the liquid in that tank at the desired level as well as for draining the tank if desired, ifdesired,supply conduit 39 interconnects theoutlet 31 of pump P with theinlet 40 ofutilization tank 14 through normallyopen supply valve 41 and through normally opened manually controllable regulatingvalve 42.

In order to return any excess liquid inutilization tank 14 to reservoir R,overflow conduit 43 is interconnected withport 44 ofutilization tank 14 and with resevoir R as is apparent in FIG. 2.

Normally closeddrain valve 45 is interconnected betweensupply conduit 39 andoverflow conduit 43 viashort drain conduit 46.

During normal operation when liquid is being supplied toutilization tanks 6 and 14, normally openedsupply valve 41 and normally opened manually controllable regulatingvalve 42 are both opened while normally closeddrain valve 45 and normally closedreturn valve 32 are closed. During these conditions liquid is supplied throughconduit 39 andport 40 toutilization tank 14 and any excess liquid overflow throughport 44 is returned throughconduit 43 to reservoir R. Should the machine stop for any reason, normallyopen supply valve 41 is closed anddrain valve 45 is opened following which valve operation liquid drains by gravity fromtank 14 throughport 40, valve 42 a portion ofsupply conduit 39, throughdrain valve 45 andsort conduit 46 and ultimately through a portion ofoverflow conduit 43 into the reservoir R sincetank 14 is at a higher elevation than reservoir R.

From the above description it is apparent that both plastic sheets S1 and S2 protected against the deleterious effects of germicidal liquid by the system in FIG. 2 which effects quick and efficient drainage of liquid from these tanks when the machine is shut down or as may otherwise be desired. Such action preferably is accomplished by electromagnetically controlled valves which in themselves are well known and which may be controlled by a manually operable switch operated independently of or in conjunction with the circuit switch which controls the operation of the machine of FIG. 1.

Furthermore the above results are accomplished while insuring that adequate germicidal action is achieved with respect to both sheets 81 and S2 during normal operation of the machine.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a packaging machine of the form-flll-seal type hereby receptacles are formed from a first web of packaging material at a forming station, filled with a product at a filling station, and provided with a cover supplied from a second web of packaging material at a sealing station, the system for treating said first and second web of packaging material with sterilizing solution, comprising a. a reservoir tank containing a supply of sterilizing solution,

b. means for heating said solution to a desired temperature,

c. a first utilization tank for treating said first web of packaging material,

d. a second utilization tank for treating said second web of packaging material,

e. means for coninuously circulating said solution from said reservoir tank to said first and second utilization tanks,

f. and means for maintaining a desired level of solution in said first and second utilization tanks.

2. A system according to claim 1 wherein means responsive to an interruption of the packaging operation effects draining said utilization tanks into said reservoir tank.

3. A system according to claim 1 wherein said means for heating said solution is associated with said reservoir tank.

4. A system according to claim 1 wherein one of said utilization tanks comprises a bottom wall of generally arcuate cnfiguration whose side edges protrude upwardly and whose mid portion is bowed downwardly,

whereby receptacles are formed from a first web of packaging material at a forming station, filled with a product at a filling station, and provided with a cover supplied from a second web of packaging material at a sealing station, the system for treating said first and second web of packaging material with a sterilizing solution, comprising a. a reservoir tank containing a supply of sterilizing solution,

b. means (associated with said reservoir tank) for heating said solution to a desired temperature,

c. a first utilization tank for treating said first web of packaging material,

d. a second utilization tank for treating said second web of packaging material,

e. means for continuously circulated said solution from said reservoir tank to said first and second utilization tanks,

f. means for maintaining a desired level of solution in said fil st and second utilization tanks,

g. and means responsive to an interruption of the packaging operation for draining said utilization tanks and returning said solution threfrom to said reservoir tank.

Claims (5)

1. 2. A system according to claim 1 wherein means responsive to an interruption of the packaging operation effects draining said utilization tanks into said reservoir tank.
2. 3. A system according to claim 1 wherein said means for heating said solution is associated with said reservoir tank.
3. 4. A system according to claim 1 wherein one of said utilization tanks comprises a bottom wall of generally arcuate configuration whose side edges protrude upwardly and whose mid portion is bowed downwardly, a similarly configured top wall spaced above said bottom wall, a pair of end walls secured to the opposite arcuate edges of said bottom and top walls to define a liquid retaining cavity of generally arcuate cross sectional configuration.
4. 5. A system according to claim 1 wherein each of said utilization tanks includes an outlet through which the associated web is fed and wherein enclosing structure is interconnected with said outlets so as to receive and maintain the associated web under asceptic conditions.
5. 6. In a packaging machine of the form-fill-seal type whereby receptacles are formed from a first web of packaging material at a forming station, filled with a product at a filling station, and provided with a cover supplied from a second web of packaging material at a sealing station, the system for treating said first and second web of packaging material with a sterilizing solution, comprising a. a reservoir tank containing a supply of sterilizing Solution, b. means (associated with said reservoir tank) for heating said solution to a desired temperature, c. a first utilization tank for treating said first web of packaging material, d. a second utilization tank for treating said second web of packaging material, e. means for continuously circulating said solution from said reservoir tank to said first and second utilization tanks, f. means for maintaining a desired level of solution in said first and second utilization tanks, g. and means responsive to an interruption of the packaging operation for draining said utilization tanks and returning said solution therefrom to said reservoir tank.

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