1. Technical Field
This invention relates generally to apparatus and methods for removal of controlled amounts of flowable materials from within sealed containers, and especially to those devices wherein food materials having wide ranges of viscosities, temperatures, and particulate contents are press pumped from flexible walled bags, which are in turn supported within a more rigid container.
2. Background Art
Flexible walled bottles have long been used to dispense fluids by means of squeezing. Such bottles have been usually made with resilient walls which tend to restore to their original shape after removal of deforming forces. As the ratio of inside air to liquid increases with bottle use, difficulties are encountered in attempting to completely empty the bottle in a timely manner. Solutions to these problems have included placement of the fluid in an inner bag which is sealed within a squeeze bottle. Examples of such structures have been disclosed by Streck in U.S. Pat. No. 4,865,224 and Uhlig in U.S. Pat. No. 4,098,434.
Although the above solutions decreased the time required to empty the bottle, they led to new problems associated with premature bag collapse with potential exit orifice blockage. Semi-rigid internal bag cartridges which lessen these problems were shown early in U.S. Pat. No. 2,608,320 to Harrison, and various supporting structures placed inside the bag are well known, as recently illustrated by U.S. Pat. No. 5,156,300 to Spahni et al. Combinations of such internal bag elements with dispensing means are available, as typified by U.S. Pat. No. 4,138,036 to Bond wherein a helical coil bag insert is coupled with a dispensing spout supported in the neck opening of a rigid external structure. Other combination devices have mated a protected dispensing orifice with bag cutting and sealing means. An example of this approach is shown by Knorr in U.S. Pat. No. 5,127,550, wherein a first member having a throughbore therein is used in conjunction with a second cutting means to seal adjacent portions of a bag wall together while piercing the bag wall for fluid release through the narrow passages cut therein.
While the above devices have been useful in dispensing relatively nonrepeatable doses of liquids having sufficiently low viscosity to permit fluid flow through given fixed exit orifices, difficulties arise in obtaining repeatable portioning of fluids over wide ranges of temperature and viscosity. In the restaurant industry for instance, such devices have been useful in manual dispensing of condiments by customers.
In the area of rapid food preparation however, a need exists to dispense well controlled portions of liquids of various viscosities, or of emulsions, or of colloidal suspensions which can coagulate or settle out with time, or of semi-solid mixtures, such as relish, beans, meat, sour cream, cheese sauces, ketchup, or mustard, all of which have very uneven flow characteristics. In addition, dispensers are required to hold and dispense product at a wide range of temperatures, and must provide maximum safety in dispensing and storage of food products in their original container. All dispensing apparatus used must be approved by the Federal Drug administration (F.D.A.), by the National Sanitation Foundation (N.S.F.) and by local safety regularity authorities. In order to meet such requirements, equipments used must be easily cleaned, made from material that does not support bacterial growth, have minimum bend radii, and eliminate cracks which can hide food particles.
Current trends in the fast food industries indicate continued world wide growth. This will require increased employment of manual labor if the industry continues to hand make the food product sold to their customers. Since this labor force is generally unskilled and has a high turn over rate, the industry will have to automate the food handling both at the restaurant level and at food manufacturing facilities. In addition to labor, cost and space savings, automation will also solve other problems. These include less manual food handling, minimization of incorrect temperature exposure, increased environmental protection, reduced waste, and a more exact ingredient portioning.
The restaurant and consumer industries are making increased use of flexible bags to contain food and other products. These bags are easy to handle and require less storage and shipping space. Current semi-automation is achieved by transferring ingredients into mechanical handheld dispensing devices or through the use of infitments. Infitments are attached to the bag and used to interface with a dispense hose or nozzle. These infitments are either placed on the bag before loading or attached at location of use. Both means increase the material cost and require additional labor to attach the infitments or fill the mechanical handheld device. Additionally, the excessive product handling necessary to dispense the ingredients causes undesirable waste and food handling risks.
Existing technology for automation at the restaurant level consists of equipment to dispense soft drinks, and timing devices for cooking or melting of food products. Some ingredient dispensing devices use peristaltic or diaphragm pumps, but are limited in their ability to accurately change portioning. Pneumatic pumps, using air pressure to discharge product from a bag are currently the only ingredient pumps that meet most of the restaurant automation requirements. For instance, they are not approved for low acid foods or foods considered to be hazardous, such as meat or beans. Pneumatic pump approaches however are limited in their ability to accurately dispense, usually have a valve and or sensors exposed to the food, and require a source of constant or regulated high pressure air. In these devices the portion or amount of ingredient that is pumped is usually dependent on one or more of the following: air pressure, its rise and fall time, duration of pressure application, valves, exit hole size and product viscosity. As the ingredients are displaced from the flexible bag, the volume of air to be pressurized increases, and the time to achieve pressurization becomes longer. If the time that the air pressure is applied is held constant, then the ingredient portion being dispensed will become smaller as the residual ingredient left in the bag is reduced. A need exists therefore, for a dispensing system which will alleviate the above problems by provision of automatic dispensing apparatus which will provide uniform controlled dosages, be adaptable to operate within an overall computer controlled automation system, and meet the demanding cost and safety requirements of the restaurant industry.