Receptacle Evacuation Apparatus And Method

Abstract

A receptacle whose interior is in communication with a portable vacuum reservoir can have its interior evacuated within a vacuum chamber and then be removed from the chamber so that final closing of the receptacle takes place outside the chamber thus freeing the chamber for a subsequent receptacle.

Description

FIELD OF THE INVENTION

This invention relates to the evacuation of receptacles to pressures lower than that of the atmosphere. Particularly, this invention relates to the evacuation and sealing of filled, flexible receptacles such as thermoplastic bags to very low pressure levels in order to preserve the contents of the receptacle. A useful application of the invention is in the packaging of food products such as meat and poultry, cheese, and other foods whose storage lifetime is increased by the absence of atmospheric air.

BACKGROUND OF THE INVENTION

It is well known to package and store articles, particularly food products, in receptacles in which substantially all of the atmospheric air has been removed. One apparatus and method for evacuating flexible receptacles such as thermoplastic bags filled with a food product is disclosed in U.S. Pat. No. 3,714,754 issued to E. L. Holcombe et al. on Feb. 6, 1973. In that patent, a thermoplastic bag filled with a food product is conveyed into a vacuum chamber where the pressure is lowered to remove the air from the bag; and, after a sufficiently low pressure has been reached the bag neck is clipped shut by the application of a metal clip which effects a hermetic or air tight closure of the bag. However, the process is somewhat slowed down by the fact that there is a delay of the product in the vacuum chamber while it is being closed. Accordingly, it is one object of the present invention to provide a method and apparatus whereby a receptacle may be evacuated within a vacuum chamber and then finally sealed and closed outside of the vacuum chamber.

Another object of the present invention is to provide a method of evacuating and sealing filled receptacles at speeds greater than prior art methods.

These and other objects accomplished by the present invention will be apparent to those skilled in the art from the following description of the invention.

SUMMARY OF THE INVENTION

The present invention is a method and apparatus whereby a receptacle whose interior is in communication with a vacuum reservoir can have its interior evacuated within a vacuum chamber and then be removed from the chamber so that final closing of the receptacle takes place outside of the chamber thereby freeing the chamber for a subsequent receptacle.

Specifically, the method of the present invention comprises the steps of providing a vacuum reservoir in communication with the interior of a receptacle; placing the reservoir and receptacle within a vacuum chamber; evacuating a chamber, reservoir, and receptacle; sealing the reservoir but leaving it in communication with the interior of the receptacle; removing said receptacle and reservoir from said chamber; and, thereafter, sealing said receptacle and severing its communication with the reservoir.

The apparatus of the present invention comprises a vacuum reservoir; means for communicating said reservoir with the interior of a receptacle; vacuum chamber for receiving said reservoir and receptacle; means for evacuating said chamber, reservoir and receptacle; means for sealing said reservoir after it has been evacuated; and, means for closing said receptacle and severing its communication with said reservoir.

In one embodiment of the present invention, the reservoir and the receptacle may be evacuated independently of the evacuation of the vacuum chamber; and, in a second embodiment, the reservoir and receptacle are evacuated as the vacuum chamber is evacuated. A chief advantage in evacuating a receptacle within a vacuum chamber according to the present invention is that as the chamber pressure is lowered more rapidly than the pressure inside of the receptacle, the receptacle will expand outwardly if it is flexible thus exposing all of its interior to the evacuation means with which it is in communication. This is especially important for meat and poultry products which have crevices and cavities and are damp when packaged so that the receptacle wall would tend to stick to the damp product thus trapping air in the crevices and cavities. Once the outward expansion or "ballooning" had taken place and the receptacle thereafter evacuated, in prior art devices it was necessary to retain the product in the vacuum chamber until it was finally clipped in order to insure that air did not leak back into the bag. In the present invention, when the receptacle is flexible and has been collapsed tightly around the product after evacuation of the receptacle, there is little, if any, space or volume within the receptacle that is not occupied by the product whereas the reservoir which is in communication with the interior of the receptacle is a relatively large volume or space which has been essentially completely evacuated of any air or gas and serves as a vacuum reservoir. The difference in volume between the vacuum reservoir and the unoccupied space within the receptacle being quite great, the reservoir can absorb any leakage of air into the receptacle when the receptacle is removed from the vacuum chamber before it is clipped, sealed, or closed.

The present invention may be even better understood by referring to the following detailed description and to the attached drawings which are described below.

DESCRIPTION OF THE DRAWINGS

In the drawings which are attached hereto and made a part hereof:

FIG. 1 is a top plan view of the vacuumizing machine employing a vacuum reservoir according to the present invention;

FIG. 2 is a side elevation view of the machine shown in FIG. 1;

FIG. 3 is a schematic representation of the operation of the vacuum reservoir within a vacuum chamber;

FIG. 4 is a perspective view of a bagged product and the reservoir assembly showing the bag's neck over the clamping nozzle;

FIG. 5 is a sectional view of a clamping nozzle; and,

FIG. 6 is a top plan view of one embodiment of a reservoir assembly according to the present invention.

PREFERRED EMBODIMENT

In FIGS. 1 and 2 a flexible receptacle or bag evacuation apparatus or machine 5 is illustrated. The major components of the machine 5 include a conveyor belt 3, a reservoir assembly 1, a vacuum chamber 4, and a bag closing means 10.

In operation these components relate to one another and function in the following manner;

Still referring to FIGS. 1 and 2, receptacles or bagged products 2 are delivered to the machine by any convenient means; e.g., infeed conveyor 6, whereupon the bagged products are deposited on the conveyor belt 3 and placed on the clamping nozzles 33 by operators 8. The bagged products are transported to vacuum chamber 4, which is raised to an open position by cam-driven pushrods (not shown), the cams rotating as the belt moves to cycle the chamber cover up and down once for each reservoir assembly 1. Sensor 32 acts to introduce vacuum to line 23 so that suction will be present at port 22 when the reservoir arrives there. After the vacuumizing operation within the chamber 4, which will be discussed hereinafter, the bagged products are conveyed to a bag sealing means located outside of the chamber; e.g., a clipping-severing device 10 supported by frame 9. The sealed bags may be transported from the machine by any effective means; e.g., discharge conveyor 7.

Referring now to FIGS. 3 and 4 wherein there is shown a schematic and a perspective view, respectively, of the reservoir assembly 1, a bagged product 2 is shown resting on conveyor belt 3 with the neck of the bag on neck or throat gathering support 24 with the open end of the bag clamped on nozzle 33. As illustrated, the nozzle is mounted on support 13 which is attached to a reservoir support plate 12 which is fixedly attached to conveyor belt 3.

Turning now to FIG. 3, which schematically represents the operation of the reservoir 11 within the vacuum chamber, there is shown an inverted U-shaped housing valve 19 wherein the top most side, having an opening therein, also serves as a valve seat for check valve 20 having closure spring 21. The housing 19 is located over an opening in plate 12 and port 22 beneath the conveyor belt. As shown in FIG. 3, when the reservoir is in operation, the port 22 lies coincidentally with vacuum line 23.

Certain variations may be made in the components of the receptacle evacuation apparatus as described and shown and still fall within the generally preferred embodiment of the present invention. For instance, it is not necessary that two bagged products be evacuated and sealed simultaneously. One or any additional number of bagged products within practical limits may be evacuated and sealed. Furthermore, although preferred, it is not necessary in some instances to employ mechanical bag closing devices of the type shown which is Tipper Clipper Model AZ4100 manufactured by the Tipper Tie Division of Rheem Manufacturing Company of New York, N.Y. and which closes the bags with metal clips. For instance, the bag's open end may be closed by heat sealing means. Any well-known sensing device 32 for actuating vacuum line 23 may be used including both electrical and pneumatic switches. The vacuum chamber cover 4, as stated before, is raised by cam-driven pushrods but may be raised by actuating means such as pneumatically driven pistons or by electrically driven motors or solenoids.

The sequence of events during the operation of the apparatus are as follows:

The major events to be sequenced are: (1) clamping the bagged products on the vacuum nozzles; (2) conveying the clamped bagged product to the vacuum chamber; (3) opening the vacuum chamber; (4) stopping the conveyor belt; (5) closing the vacuum chamber; (6) evacuating the chamber; (7) evacuating the reservoir assembly; (8) discontinuing evacuating chamber, (9) venting chamber to atmosphere; (10) conveying bagged product which is under vacuum because of the reservoir to a bag sealing device; (11) sealing the bag and severing it from the nozzle which automatically vents the reservoir assembly to atmosphere; and (12) conveying the sealed bagged product to the discharge end of conveyor.

Most of the components required for the sequencing events, as outlined heretofore, are well known in the art; e.g., as shown in U.S. Pat. No. 3,714,754, which was mentioned hereinabove.

Turning now to the clamping nozzle, its operation will be described below:

Many different evacuation nozzle designs are available and applicable to the operation of this receptacle evacuation apparatus, particularly when the receptacle is flexible. One particularly pertinent nozzle is disclosed in U.S. Pat. No. 3,094,825. The nozzle disclosed in this patent has a coaxially disposed flared nozzle extension in the center of the nozzle barrel which serves to clamp the neck of a bag between the flared extension or plunger and the barrel of the nozzle.

Another pertinent nozzle is disclosed in U.S. Ser. No. 258,665, now U.S. Pat. No. 3,780,489, which is assigned to this assignee of the present application. The nozzle disclosed in this patent has a barrel slidably mounted in a cover and has upper and lower nozzle portions coaxially positioned in the barrel. The upper and lower portions have mating flanges and are resiliently held together. Attached to the lower end of the lower nozzle portion is a flared resilient plunger which is positioned outside of the barrel so that a bag neck can be clamped therebetween. The lower nozzle portion can be swung a limited distance like a pendulum and such motion will separate the mating flanges on the nozzle portions. The upper portion is provided with a central vacuum duct or passageway and the separation of the flanges will introduce vacuum into the barrel, and the barrel, being slidably mounted, will move down upon the plunger under the force created by the air pressure differential, thus clamping the bag between the plunger and the barrel and at the same time introducing vacuum into the interior of the bag. This clamping action will hold a filled bag. The vacuum valve and clamping action are released by the introduction of compressed air into the barrel.

In addition to the two above described nozzles, the preferred clamping nozzle 33, as shown in FIG. 5 has a barrel 14 moveably mounted on plunger 16 which is fixedly connected to clamping nozzle support 13. As shown in FIGS. 3 and 4 said nozzle support is mounted on reservoir support plate 12 which in turn is mounted to conveyor belt 3. Flared plunger head 25 is located on the external forward end of the plunger and annularly located in the internal forward portion of the barrel is chamber or cavity 30 having a vacuum supply line 15 (vacuum source not shown) connected thereto. A second vacuum line 23A runs through the plunger and plunger head of the nozzle and is connected to product evacuation line 18 from the reservoir (FIGS. 3 and 4) to communicate the interior of the bag or receptacle with the interior of the reservoir.

A locking handle 17 is moveably mounted to the barrel by means of handle pivot plate 27. Said pivot plate is pivotally attached to the barrel and is further attached to arm 26 at second pivot point 29'. Said arm is pivotally attached at third pivot point 29" to a fixed pivot plate 28 which in turn is attached to support 13.

The advantage of the design of nozzle 33 over prior art is better illustrated by an understanding of the operation of this unique clamping nozzle. The neck of a bag 2 is placed around barrel 14 of nozzle 33 (not shown) by an operator 8 (FIG. 1) and a vacuum is applied to barrel chamber 30 through passageway 15. Because of the force created by the air pressure differential, the moveable barrel will slide toward plunger head 25 thereby clamping the neck of the bag between the barrel and the plunger head. To further clamp the neck of the bag between the barrel and plunger head the operator pushes handle 17 toward support 33 to a closed position thereby forcing the barrel against the plunger head forming a leak proof clamp around the neck of the bag.

Next, the operation of the reservoir assembly will be described with reference to FIGS. 3, 4, and 6 in the following paragraphs:

In FIG. 4 the components of the reservoir assembly are shown in perspective. Support plate 12, nozzle support 13, clamping nozzle 33, receptacle evacuation line 18, and reservoir 11 comprise the reservoir assembly. Also included for bag-like flexible receptacles is bag neck gathering support 24. The support plate 12 which supports the other components is carried by conveyor belt 3. These same components of reservoir assembly 1 may be seen in FIG. 6 where a top plan view of the assembly is shown. The top wall of reservoir 11 is broken away to show the location of check valve 20 in the bottom wall of the reservoir. Reservoir latches 31 allow the reservoir to be opened and cleaned should any moisture or debris collect in the reservoir. In FIG. 6, clamping nozzle 33 is shown with the clamping plunger 25 (see FIG. 5) closed against barrel 14 so that the locking handle 17 is in the "down" or locked position whereas in FIG. 5, handle 17 is in the "up" or unlocked position.

In operation, the neck or throat of a bag or receptacle 2 will be placed around nozzle 33 as shown in FIG. 4. The nozzle is then actuated and the bag clamped securely as described above. Then, the bag 2 and reservoir assembly are placed in a vacuum chamber 4 as shown in FIG. 3. In the preferred embodiment, as shown, the check valve 20 is aligned with flanged vacuum port 22 so that air can be withdrawn through the aligned orifice which is defined by the lower opening of valve housing 19 as the housing extends through support plate 12 and through a matching orifice in belt 3. When the air pressure in vacuum line 23 is lowered below the pressure in the reservoir 11, valve 20, which is hingedly attached to housing 19 to cover the upper opening or orifice of housing 19, will be forced open against valve spring 21 by the difference in pressure. When the pressure in the line 23 or, after movement from alignment with line 23, when the pressure exterior of the reservoir 11 is greater than that in the reservoir, valve 20 will close. It is to be understood that other valves could be used and be within the scope of the present invention. For example, a poppet valve, a ball valve, or a butterfly valve could be used. The valve spring in each instance would, of course, have to be selected so that the valve opens at the desired pressure differential. One preferred valve is a swing check valve Model Number 583-1D2 made by Teledyne Rupublic Manufacturing Co.

Still referring to FIG. 3, once evacuation has begun in the vacuum chamber 4 through line 34 which is connected to a vacuum pump (not shown) which is preferably a conventional pump such as a 300 CFM Nash pump, the bag or flexible receptacle 2 will balloon outwardly as indicated by dotted line 2' due to the pressure difference between the inside and outside of the bag. If the bag or receptacle has been filled with a meat or poultry product containing crevices or cavities, these crevices will now be subjected to evacuation when air is withdrawn through vacuum line 23, valve 20, reservoir 11, line 18, and nozzle vacuum line 23A. (see FIG. 5) The vacuum applied through line 23 may come from the same pump as used to evacuate the chamber 4 or it may be from an independent pump. Once the evacuation of the receptacle 2 and reservoir 11 is complete atmospheric air will be introduced into the chamber causing the receptacle 2 to collapse upon the product inside. When the vacuum to line 23 is stopped, the valve 20 will close and the reservoir assembly 1 and receptacle 2 are moved to clipper 10 (see FIG. 1) outside the chamber 4 for final closure of the receptacle. Since virtually all air has been removed from the receptacle any leakage of air into the receptacle will be evacuated to reservoir 11 as the difference in volume is so great that the lower pressure will be effectively maintained. For example, in one embodiment the reservoir has a volume of about 350 cubic inches while there is virtually no measureable cavity volume in the flexible receptacle because its walls are collapsed and held against the product by the pressure differential of about 29 inches of Hg. Thus, clipping the receptacle outside the vacuum chamber while a subsequent package is being evacuated within the chamber saves the time of the entire clipping procedure each cycle of the apparatus.

Referring again to FIG. 3, in another embodiment, valve 20 with its housing 19 may be placed in a side or top wall of reservoir 11 and the bottom wall will not be provided with an opening. This configuration is not shown in FIG. 3; but, when used, the bag 2 will balloon outwardly as before because the pressure in chamber 4 will decrease more rapidly then the pressure inside the reservoir and bag because the air leaving bag 2 has a more restricted path to travel by going through line 18, reservoir 11, and valve 20. This embodiment makes use of one vacuum line 34 and eliminates the need for vacuum line 23 as the check valve 20 will open to evacuate the reservoir 11 and bag 2 as soon as the chamber 4 pressure is lowered.

Claims

Having thus described our invention, we claim:

1. In the method of evacuating receptacles within a vacuum chamber, the improvement which comprises:

a. providing a portable vacuum reservoir;

b. placing said receptacle and said reservoir within a vacuum chamber, said reservoir being in communication with the interior of said receptacle;

c. evacuating said reservoir and said receptacle;

d. sealing the evacuated reservoir while leaving it in communication with the receptacle; and,

e. removing the receptacle and reservoir from said chamber and thereafter closing said receptacle.

2. The method of claim 1 wherein said receptacle is a flexible, thermoplastic bag.

3. The method of claim 2 including the step of evacuating the vacuum chamber while said reservoir and receptacle are being evacuated.

4. The method of claim 4 including the steps of providing a nozzle in communication with said reservoir and clamping the neck of the bag thereto.

5. A method of evacuating receptacles containing a product comprising the steps of:

a. providing a vacuum reservoir in communication with the interior of said receptacle;

b. placing said reservoir and receptacle in a vacuum chamber;

c. evacuating the chamber, reservoir, and receptacle;

d. sealing the reservoir but leaving it in communication with the interior of the receptacle;

e. removing said receptacle and reservoir from said chamber; and, thereafter,

f. sealing said receptacle and severing its communication with said reservoir.

6. Apparatus for evacuating receptacles comprising:

a. a vacuum reservoir;

b. means for communicating said reservoir with the interior of a receptacle;

c. vacuum chamber means for receiving said reservoir and receptacle;

d. means for evacuating said chamber, reservoir, and receptacle;

e. means for sealing said reservoir after it has been evacuated; and,

f. means for closing said receptacle and severing its communication with said reservoir.

7. The apparatus of claim 6 wherein the means for communicating said reservoir with the interior of a receptacle is a clamping nozzle with an evacuation port and passageway therein.

8. The apparatus of claim 7 including a conveyor belt to transport said receptacles to and away from said vacuum chamber.

9. The apparatus of claim 8 wherein said clamping nozzle and said reservoir are mounted on a support plate, said plate being mounted on said conveyor belt.

10. The apparatus of claim 9 including a port and check valve in a wall of said reservoir whereby said reservoir will be evacuated as said chamber is evacuated.

11. The apparatus of claim 9 wherein said reservoir has a bottom port and a valve to control the opening and closing thereof, said support plate and conveyor belt having orifices aligned with said port whereby said reservoir may be evacuated through said port and orifices.

12. Apparatus for evacuating filled, flexible receptacles comprising:

a. a conveyor belt mounted for intermittent motion, said belt having an evacuation orifice therein;

b. a support plate mounted on said conveyor, said plate having an orifice aligned with the orifice in said belt;

c. a clamping nozzle mounted on said plate, said nozzle being adapted to clamp the necks of flexible receptacles thereto;

d. a vacuum reservoir mounted on said plate, said reservoir having a port in its bottom wall aligned with said orifices;

e. a valve for controlling the opening and closing of said port, said valve opening when the air pressure in said port and orifices is lower than the pressure in the reservoir and closing when the air pressure in said port and orifices is equal to or greater than the pressure in said reservoir;

f. a vacuum line connecting said clamping nozzle and said reservoir whereby the interior of a clamped receptacle is in communication with said reservoir;

g. a vacuum chamber into which said reservoir and nozzle may be conveyed by said belt;

h. a vacuum port beneath said belt whereby said orifices and reservoir port may be aligned when said reservoir and nozzle are within said chamber;

i. means for evacuating said chamber;

j. means for evacuating said reservoir through said ports and said orifices;

k. means outside said chamber for closing and severing the receptacle while it is in communication with said reservoir.

13. The apparatus of claim 12 wherein said clamping nozzle comprises a slidable barrel; a clamping plunger mounted coaxially within said barrel, said plunger having an evacuation passageway therethrough; and, a locking handle to hold said plunger and barrel in a fixed position with a portion of the neck of a receptacle clamped therebetween.

14. Apparatus for evacuating filled, flexible receptacles comprising:

a. a conveyor belt mounted for intermittent motion;

b. a support plate mounted on said conveyor;

c. a clamping nozzle mounted on said plate, said nozzle being adapted to clamp the necks of flexible receptacles thereto;

d. a vacuum reservoir mounted on said plate, said reservoir having a port in one of its walls;

e. a valve for controlling the opening and closing of said port, said valve opening when the air pressure exterior of said reservoir is lower than the pressure inside the reservoir and closing when the air pressure exterior of said reservoir is equal to or greater than the pressure inside said reservoir;

f. a vacuum line connecting said clamping nozzle and said reservoir whereby the interior of a clamped receptacle is in communication with said reservoir;

g. a vacuum chamber into which said reservoir and nozzle may be conveyed by said belt;

h. means for evacuating said chamber whereby said reservoir and bag interior are consequently evacuated; and,

i. means outside said chamber for closing and severing the receptacle while it is in communication with said reservoir.