TECHNICAL FIELD

The present invention relates to an automated

product draining method for a packaging machine. More

specifically, the present invention relates to a clean,

automated product draining method for a packaging

machine.

BACKGROUND

Packaging machines are known that integrate into a

single unit the various components necessary to form a

container, fill the container with a liquid product, and

seal the container. Such packaging machines typically

feed carton blanks into the machine, seal the bottoms of

the cartons, fill the cartons with a product dispensed

from a product storage tank through a filling tube, seal

the tops of the cartons, and off-load the filled cartons

for shipping.

Where the liquid product dispensed into the cartons

is a liquid foodstuff it may be necessary to maintain a

sterile filling environment. The sterile filling

environment must be maintained in the product storage

tank, the filling tube, and in a region surrounding a

terminus of the filling tube from which the product is

dispensed. The region surrounding the terminus of the

filling tube can be partially enclosed, for example, by

a casing. Further, the sterile filling environment must

be maintained in an area below the terminus of the

filling tube, extending as far below the terminus as is

necessary to ensure that non-sterile air is effectively

prevented from penetrating the area surrounding the

terminus of the filling tube.

In order to prevent bacteria from forming in parts

of the packaging machine that come into contact with

certain liquid foodstuffs it is known to circulate a

cleaning fluid through those parts. However, any liquid

product remaining in the product tank at the end of the

production cycle must be drained from the product tank

before the cleaning cycle can begin.

Typically, the remaining product is drained from

the product tank by opening the pump valves in the

system such that the remaining product flows out of the

product tank and into the casing, or where a casing is

not provided, onto a draining floor, at atmospheric

pressure under the force of gravity. As the remaining

liquid product is drained from the product tank in this

manner it tends to splash in the casing and becomes

unsuitable for reuse. Specifically, the remaining

product tends to foam and may become contaminated as it

is drained from the product tank. Therefore, the

remaining product is disposed of once it is drained from

the system. Since packaging machines must be frequently

cleaned, regularly disposing of the remaining product is

costly.

SUMMARY OF THE INVENTION

A clean, automated product draining method for a

packaging machine is set forth. The method includes the

following steps: draining product from a product tank

through a filling tube; and controlling a rate at which

the product is drained from the product tank with a

dispensing mechanism, wherein the product is drained at

a slower rate than the rate at which the product is

dispensed into a container during a production cycle .

Other objects and advantages of the present

invention will become apparent upon reference to the

accompanying detailed description when taken in

conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the draining of product into an

upper end of a filling tube in accordance with the

disclosed method.

FIG. 2 illustrates the draining of product into

a lower end of a filling tube in accordance with the

disclosed method.

FIG. 3 illustrates graphically the controlling

sequence for draining the product .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated in FIG. 1, product from a product

tank 10 of a packaging machine can be drained from a

filling tube 12. The rate, or flow at which the product

is drained is controlled with a suitable dispensing

mechanism, such as a pump 14, that, for example, may be

a servomotor driven pump under control of a control

system, such as is disclosed in U.S.S.N. 08/475,396

(Corporate Docket No. TRX-0126; Attorney Docket No.

10623US01) , entitled "Control System for a Packaging

Machine", filed on September 28, 1994 and incorporated

by reference. Where the pump 14 is used as the

dispensing mechanism, inlet and outlet valves 16, 18 can

be sequentially activated to assist in controlling the

rate of flow at which the product is drained. In this

case, the outlet valve 18 is disposed between the

product tank 10 and a dispensing end 20 of the filling

tube 12. The inlet valve 16 is disposed between the

outlet valve 18 and the product tank 10. The pump 14 is

disposed between the inlet valve 16 and the outlet valve

18. The method is then carried out as follows.

First, the outlet valve 18 is closed. Next, the

inlet valve 16 is opened. A return stroke of a piston

22, as indicated by the arrow in FIG. 1, of the pump 14

is activated when or as the inlet valve 16 is opened.

The product then drains into a region 24 of the filling

tube 12 between the product tank 10 and the outlet valve

18. The inlet valve 16 is then closed, and then the

outlet valve 18 is opened. As the outlet valve 18 is

opened, a forward stoke of the piston 22, as indicated

by the arrow in FIG. 2, is activated. The product then

drains through a second region 26 of the filling tube 12

between the outlet valve 18 and the dispensing end 20 of

the filling tube 12.

As the product drains out of the dispensing end 20

of the filling tube 12, the product must enter a clean

draining environment, or it may become contaminated and

unusable. As illustrated in FIGS. 1 and 2, the draining

environment can include a clean chamber 28 formed by a

cleaning box and a clean, automated cover as is

discussed more fully in U.S.S.N. 08/316,109 (Corporate

Docket No. TRX-0101; Attorney Docket No. 10586US01) ,

filed on even date herewith and incorporated by

reference. A drain pipe 30 can be connected to, for

example, a lower end of the clean chamber 28. The

product can then drain into the clean chamber 28 and

through the drain pipe 30. The illustrated system is a

closed system that includes a vent pipe, such a system

being disclosed in U.S.S.N. 08/315,958 (Corporate Docket

No. TRX-0099; Attorney Docket No. 10580US01) , filed on

even date herewith and hereby incorporated by reference.

In order to prevent the product from splashing as

it enters the clean chamber 28, the pump 14 is operated

at a slower rate than a rate at which the product is

dispensed into a container during a production cycle.

The slower rate can, for example, be 50% or less of the

rate at which the product is dispensed. More

specifically, the slower rate may be 10-25% of the rate

at which the product is dispensed.

FIG. 3 is an exemplary timing diagram illustrating

operation of the inlet valve 16, shown at line 32, the

outlet valve 18, shown at line 34, and the pump 14,

shown at line 36.

Although the present invention has been described

with reference to specific embodiments, those of skill

in the art will recognize that changes may be made

thereto without departing from the scope and spirit of

the invention as set forth in the appended claims.