Compositions for an methods of lubricating carcass conveyor

Abstract

An improved method for applying an electrically charged lubricant on an oppositely charged carcass trolley in a meat packing plant meeting the requirements of (1) adequate lubricity, (2) “drip-resistance,” (3) safety, (4) rust resistance, (5) economy of manufacture and use, and (6) the ability to be removed by cleaning methods is provided by preparing a mixture of mineral oil, a fatty acid, a silicone oil, and a polybutene, each being acceptable for incidental contact with food.

Claims

1. A method of applying a lubricant on conveyor machinery used in a meat packing plant, wherein such lubricant is electrically charged and safe for incidental contact with food; comprising: selecting the lubricant components from a mineral oil, at least one fatty acid, at least one H1 silicone oil, and a polybutene, each component being acceptable for incidental contact with food; mixing such mineral oil, at least one fatty acid, at least one H1 silicone oil, and polybutene in at least the following minimum percentages by weight: TABLE-US-00010 Fatty Acid 2.5%  Mineral Oil 50% Polybutene  3% H1 Silicone Oil .sup. 1%; applying an electrical charge to one or more portions of a carcass trolley; applying an opposite electrical charge to the lubricant to form an electrostatically charged lubricant; and applying the electrostatically charged lubricant to one or more portions of the carcass trolley.

2. The method of claim 1, wherein applying an opposite electrical charge to the lubricant to form an electrostatically charged lubricant comprises applying an electrical charge to the lubricant in a container.

3. The method of claim 1, wherein applying an opposite electrical charge to the lubricant to form an electrostatically charged lubricant comprises applying an electrical charge to a sprayer or nozzle capable of electrically charging the lubricant.

4. The method of claim 1, wherein applying an electrical charge or an opposite electrical charge comprises contact charging, corona charging, inductive charging, and/or ionization.

5. The method of claim 1, further comprising mixing a rust inhibitor to said mineral oil, at least one fatty acid, at least one H1 silicone oil, and polybutene.

6. The method of claim 1, wherein at least 65% to 90% by weight of mineral oil is added to said mixture.

7. The method of claim 1, wherein said at least one fatty acid comprises stearic acid and oleic acid.

8. The method of claim 1, wherein at least 2.5% to 15% by weight of at least one fatty acid is added to said mixture.

9. The method of claim 1, further comprising increasing the percentage by weight of said mineral oil, at least one fatty acid, silicone oil, and polybutene to form a lubricant mixture having a viscosity in the range of 20-160 cp.

10. The method of claim 1, wherein said mixture comprises: about 85% by weight of mineral oil; about 8% by weight of at least one fatty acid; about 2% by weight of at least one H1 silicone oil; and about 4% by weight of polybutene.

11. The method of claim 1, further comprising increasing the percentage by weight of said mineral oil, at least one fatty acid, silicone oil, and polybutene to form a lubricant mixture having a viscosity in the range of 20-160 cp.

12. The method of claim 11, wherein applying an opposite electrical charge to the lubricant to form an electrostatically charged lubricant comprises applying an electrical charge to the lubricant in a container.

13. The method of claim 11, wherein applying an opposite electrical charge to the lubricant to form an electrostatically charged lubricant comprises applying an electrical charge to a sprayer or nozzle capable of electrically charging the lubricant.

14. The method of claim 11, wherein applying an electrical charge or an opposite electrical charge comprises contact charging, corona charging, inductive charging, and/or ionization.

15. The method of claim 11, further comprising mixing a rust inhibitor to said mineral oil, at least one fatty acid, at least one H1 silicone oil, and polybutene.

16. The method of claim 11, wherein at least 65% to 90% by weight of mineral oil is added to said mixture.

17. The method of claim 11, wherein said at least one fatty acid comprises stearic acid and oleic acid.

18. The method of claim 11, wherein at least 2.5% to 15% by weight of at least one fatty acid is added to said mixture.

19. The method of claim 11, wherein said mixture comprises: about 85% by weight of mineral oil; about 8% by weight of at least one fatty acid; about 2% by weight of at least one H1 silicone oil; and about 4% by weight of polybutene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of the present invention will be apparent from an examination of the following detailed description which includes the attached drawings in which:

(2) FIG. 1 is a flow chart identifying the steps taken to prepare a trolley for carrying a carcass during the processing of food for human consumption, where the step of lubricating the trolley is according to the method of the present invention;

(3) FIG. 2 is a side view of the carcass conveyor showing part of a carcass suspended from a trolley that is supported by a rail. The lubricant drip problem is illustrated by drips of lubricant falling from the trolley onto the carcass.

DETAILED DESCRIPTION OF THE INVENTION

(4) In FIG. 1, there are shown the steps in the process of preparing the trolleys 18 of such conveyor 10 for carrying the carcass 11 as shown in FIG. 2.

(5) In preparation for a lubrication step 27, in a step 28 components of the lubricant 21 are mixed in accordance with the following description to produce the lubricant 21 having desirable lubricity properties and improved drip-resistance. The lubricant 21 is fed into a tank (not shown) that is maintained at an elevated temperature, typically about 170° F. In step 40, the lubricant mixture 21 is charged and maintained there for a period of time (in some embodiments, about 10 seconds). In step 42, the trolley 18 is maintained at a different electrostatic potential by applying a charge opposite of that used to create the electrostatically charged lubricant. In step 44, the electrostatically charged lubricant is applied to one or more parts of the trolley 18 in order to permit the electrostatically charged lubricant 21 to thoroughly coat the bearing surfaces on the hanger 17 and on the bearing surfaces between an axle pin 14 and a wheel 13, so that the hook/gambrel will move freely relative to the hanger 17 and so that the wheel 13 will rotate freely relative to the axle pin 14. The charged lubricant will then be drawn to desired surfaces of the trolley 18 by electrostatic attraction.

(6) In an alternative embodiment, step 40 is not conducted. Instead, the lubricant mixture 21 is charged when emitted from a spray device (e.g., an electrostatic sprayer or nozzle) toward the trolley. The system may be in the form of any suitable apparatus for applying an electrostatic enhanced lubricant. The lubricant may be transported to the spray device in a fluid stream such as air, or in the form of liquid, or the like. The lubricant may be atomized by the spray device utilizing conventional air atomization, hydraulic atomization, and/or rotary atomization. The spray device may include one or more electrodes which cause the particles emitted by the spray device to carry an electrostatic charge such that when the charged lubricant are propelled by the spray device toward the trolley. One or more parts of the trolley 18 (e.g., wheel 13, axle pin 14, and/or hanger 17) are maintained at an electrostatic potential different than that of the charged coating particles, such that the coating particles will be deposited on the trolley with improved efficiency and coverage.

(7) In all of the embodiments herein, the electrical charge transfer mechanism may involve any suitable means, such as contact charging, corona charging, inductive charging, and/or ionization, etc. in accordance with charging principles which are well known in the electrostatic field.

(8) With continued reference to FIG. 1, the freely rotatable wheel 13 will roll along rail 12, even under the weight of the carcass 11, so as to decrease resistance and to avoid forming sliders. At the elevated temperature the lubricant 21 flows more thoroughly onto the bearing surfaces of the axle pin 14 and the wheel 13, and hanger 17. Due to the differential electrostatic charges between the lubricant and the trolley, the lubricant can coat the entire trolley, including non-moving parts to inhibit rust under the hot, steamy conditions from the kill floor and the cold, moist conditions in the “hot box.” The use of electrostatically charged lubricant on a trolley having a different electrostatic potential will also reduce drip and reduce the amount of lubricant needed.

(9) In the next step 29, the trolley 18 optionally can be blown with air so as to remove excess lubricant 21 that may be retained on the outside of the various parts of the trolley 18. Alternatively, the trolley 18 optionally may be sprayed with water to remove the excess lubricant. Using the electrostatically charged lubricant 21 of the present invention, a minimum of excess lubricant will be retained on the trolley 18 following step 29. Also, consistent with the improved “drip-resistant” properties of the electrostatically charged lubricant 21 of the present invention, dripping of the lubricant 21 from the trolley after the blowing or spraying step 29 is minimized or eliminated.

(10) The next step 30 is shown as loading the carcass 11 on hooks 19 or gambrels (not shown) of the trolley 18. Such loading of the carcass 11 is done in the kill room, where the ambient temperature is generally in the range of 80° F.-90° F. Any given trolley 18 may be loaded with a carcass 11 very soon after the blowing or spraying step 29, or there may be a delay in such loading, all according to the rate at which carcasses 11 are being processed in the meat packing plant and the number of trolleys 18 that are in service. Since the lubricant 21 must be suitable for use when such delay is minimal, the amount of dripping of the lubricant 21 from the trolley 18 should be minimal immediately after application of the electrostatic lubricant or the blowing (or spraying) step 29. In other words, the “drip-resistant” properties of the lubricant 21 should be effective before carcass 11 is loaded onto the trolley 18.

(11) With the weight of the carcass 11 on one or more of the trolleys 18, as the carcass 11 is moved along the path defined by the rail 12, the rolling of the wheel 13 tends to remove the lubricant 21 from the bearing surfaces of the wheel 13 and the axle pin 14. The lubricant 21 must also have a viscosity and electrostatic potential sufficient to resist such removal and should have sufficient load bearing capacity to lubricate such bearing surfaces under the weight of the carcass 11. These properties are required at the ambient temperature in the kill room, which as noted above can be in the range of 80° F.-90° F. The carcass 11 is hung from the trolley as soon as the shank is skinned. The carcass 11 is kept in the kill room suspended on the trolley 18 as the remainder of the carcass 11 is skinned, the head is removed, the carcass is gutted, and the carcass is inspected, trimmed and washed. This usually takes about 20 minutes. The exposure in the kill room at elevated temperatures is sufficiently long that the less drip-resistant lubricants of the prior art tend to flow easily and drip excessively onto the carcasses below.

(12) The present invention also has application in large pork plants that use blast freezers. As most hogs are dehaired (as opposed to being skinned), the gambrel is inserted immediately after the hog exits the dehairing machine. The hog carcasses typically go to a blast freezer in place of the hot box, and then go directly into a tempering cooler at 34 F.

(13) The carcass 11 is then moved into the “hot box” (step 31) where the ambient temperature is below 32° F., generally at about 26° F. The carcass 11 is generally kept there for up to 24 hours to permit the carcass 11 to cool. During that period of time, chilled water at a temperature at or near freezing may periodically be sprayed over the carcasses to help cool the carcasses and to reduce shrinkage. Because of the length of time in the “hot box” and the periodic water spray, the prior art lubricants typically dripped from the conveyor to the carcasses below, even through the temperatures were quite cold. In contrast, the lubricant 21 of the present invention substantially reduces the drip problem even though the carcass 11 typically remains suspended on the trolley 18 in the “hot box” for 24 hours and is subjected to the water spray. Since the carcass 11 must be moved within the “hot box,” the lubricant 21 must also retain its lubricity at these colder temperatures.

(14) In step 32, the carcass 11 is moved into the sales cooler and graded. The ambient temperature of the sales cooler is usually about 34° F., or slightly above the freezing temperature of water. In the sales cooler, the meat may be sold in bulk to customers or it may be fabricated by the meat packer. If it is sold, the carcass may be removed from the trolley for delivery to the customer or both the trolley and carcass may be delivered to the customer. The practice in the industry is for customers to return uncleaned trolleys to the packing plant where they are typically reattached to the conveyor in the sales room.

(15) If a decision is made to fabricate the carcass, it may be kept in the sales cooler for up to 16 hours. The lubricant 21 must continue to retain improved drip-resistance and lubricity during this time period. During fabrication, the remainder of the carcass 11 is removed from the trolley 18 (step 33). After the carcass is removed, the trolley 18 then exits the sales cooler and is sent to step 34 for cleaning.

(16) At a cleaning station (step 34), a hot alkaline solution is applied to the trolley 18, including a hanger 17, the wheel 13, the axle pin 14, and the bearing surfaces between the wheel 13 and the axle pin 14 by dipping them in the solution. The solution removes any remaining portions of the carcass 11, dirt, lubricant, and bacteria from the parts of the conveyor 10 which come in contact with the meat. In the next step 35, these parts of the conveyor 10 are rinsed with water to remove the alkaline solution.

(17) The drip problem that is minimized by the method of the present invention and by using the electrostatically charged lubricant of the present invention may be understood by referring to FIG. 2, where a representative conveyor 10 used in meat packing plants is shown for suspending an animal carcass 11 in position to be trimmed. The conveyor 10 includes a rail 12 mounted along a path that the carcass 11 is to take as it is processed. A wheel 13 having an annular groove (not shown) formed therein rolls on the rail 12. The axle pin 14 extends through a hole 15 in the wheel 13 for supporting spaced arms 16 that extend upwardly and join the hanger 17 that extends downwardly beneath the rail 12. Bearing surfaces (not shown) are provided on the axle pin 14 and the hole 15 of the wheel 13. This assembly that is supported on the wheel is referred to as a trolley 18. In the trolley 18 shown in FIG. 2, the hook 19 extends through the hanger 17 and supports one leg 20 of the carcass 11 that is to be processed as it is moved through the meat packing plant. For lighter animals, a gambrel (not shown) supports both hind legs of the carcass 11 to be processed.

(18) The dripping problem is illustrated in FIG. 2. Excess lubricant 21 around the pin 14, the arms 16, and the wheel 13 has flowed under the influence of gravity to form a drop 22. A previously formed drop 22 of the lubricant 21 is shown falling onto the carcass 11. Lubricant 21 is shown on an exposed surface 23 of the carcass 11. Since the lubricant 21 is only approved by the U.S.D.A. for incidental contact with the carcass, the U.S.D.A. Inspector must quickly find any lubricant 21 on the carcass, the lubricant 21 must be removed promptly from the carcass 11 by trimming the carcass 11, and then the carcass 11 is subject to reinspection to determine that all of the lubricant 21 has been removed via the trimming operation.

(19) A method of the present invention renders a carcass conveyor lubricant more drip-resistant, without any substantial adverse effect on the lubricity of such lubricant or the other properties desirable for a lubricant used on a trolley in a meat packing plant. This involves the novel electrostatically charged mixture of polybutene, silicone oil, fatty acid, and mineral oil.

(20) The combined properties including lubricity and drip-resistance of the lubricant 21 will be maximized when these components are used in the following minimum percentages by weight and with the lubricant 21:

(21) TABLE-US-00001 Minimum % By Weight Fatty Acid 2.5% Mineral Oil 50.0% Silicone Oil 1.0% Polybutene 3.0%

(22) In particular embodiments, the weight of each such component that is required to result in the lubricant 21 having a viscosity in the 5-160 or 20-160 centipoise range will vary according to the viscosity of each component. As such, it is understood that a person of skill in the art may modify the amount of each component making up the lubricant according to viscosity of each component in order to formulate a desired lubricant and vary the viscosity of the lubricant mixture.

(23) Reference to the Renoil brands of mineral oil in the Charts below are to food grade mineral oils sold by Renkert Oil, Elverson, Pa. 19520, having an SUS viscosity indicated by the brand number. In particular examples, the lubricant contains at least 65% to 90% by weight of mineral oil. In other embodiments, the lubricant contains at least 80% to 85% by weight of mineral oil.

(24) Suitable fatty acids for use in the present invention include one or more food grade fatty acids, such as, for example, stearic acid and oleic acid. Representative oleic acids suitable for use in the invention includes Emersol brand oleic acid sold by Emery Oleochemicals LLC, Cincinnati, Ohio 45232, and Pamolyn brand oleic acid sold by Hercules, Incorporated, Wilmington, Del. The listed molecular weights can be obtained by the vapor phase method and the viscosity in centipoise can be obtained with a Brookfield viscometer. Other fatty acids commonly used to provide lubricity may be used including castor oil, coco fatty acid, vegetable oils and others. In particular examples, the lubricant contains at least 2.5% to 15% by weight of at least one fatty acid.

(25) Silicone oils suitable for use with the present invention include any food grade polymerized siloxanes with organic side chains, silicon analogues of carbon-based organic compounds, and related structures that form molecules based on silicon rather than carbon. In a particular embodiment, the silicone oil of the mixture can include a polydimethylsiloxane (PDMS) having a viscosity of 350 cp. or a combination of PDMSs having a combined viscosity of 350 cp., such as those available from various companies such as GE, Dow Corning, Wacker, Rhodorsil, and Shinetsu. It has been observed that silicone oil tends to cling preferentially to metal surfaces during the process of conveying a meat carcass through a conveyor in a meat packing plant, thereby reducing dripping. Additionally, it has been observed that inclusion of silicone oil to the lubrication mixture reduced the oxidation of the fatty acid(s) in the lubricant mixture, thus prolonging the service life of the lubricant mixture.

(26) The INDOPOL brand polybutenes are sold by Amoco Chemicals Corporation, Chicago, Ill. 60601. Another representative polybutene suitable for use with the invention includes Parapol 950 polybutene, which is sold by Exxon Chemicals, Houston, Tex. 17001. These polybutenes are not, as such, listed in 21 CFR § 178.3570. Since they include a basic isobutylene-butene copolymer that is acceptable under 21 CFR § 177. 1430(b)(3), they are approved for use as a component of non-food articles that comply with 21 CFR § 178.3570. Specifically, the INDOPOL brand polybutenes are made by polymerizing an isobutylene-rich butene stream with a metal halide catalyst. The polymer backbone structure resembles polyisobutylene, although more 1- and 2-butenes are incorporated in the lower molecular-weight fractions. There is a molecular weight distribution of the grades of such INDOPOL brand polybutenes. Because of their highly substituted structure, polybutenes have very low glass-transition temperatures and pour points. Such INDOPOL brand polybutenes are composed predominantly of high molecular weight mono-olefins (85-98%), the balance being isoparaffins. The olefin structure is predominantly the trisubstituted type (R—CH═CR.sub.2). Only minor amounts of vinylidene

(27) ##STR00001##
and terminal vinyl (R—CH═CH.sub.2) structures are present.

(28) The major component of polybutenes can be represented as:

(29) ##STR00002##
It is understood that some internal double bonds may exist. In particular examples, the lubricant contains at least 3% to 30% by weight of polybutene. In other examples, the lubricant contains at least 3% to 10% of polybutenes.

(30) In addition, the mixtures of this invention may contain any of the commonly recognized U.S.D.A. rust inhibitors, antioxidants, or surfactants in amounts consistent with the general principles set forth herein.

(31) In a particular embodiment of the invention, the lubricant for use on conveyor machinery in a food processing plant includes the following:

(32) TABLE-US-00002 Description Quantity Renoil.sup.1 70W 6.12799 LB GE Silicone.sup.2 SF96-350 0.14251 LB Stearic Acid 0.07126 LB Indopol.sup.3 H-100 0.28502 LB Oleic Acid (Emersol 233) 0.49879 LB .sup.1Renoil is a brand name for white mineral oil. .sup.2GE Silicones SF96-350 is a brand name for silicone oil. .sup.3Indopol is a brand name for polybutene.

(33) It is understood that the lubricant may also contain other commonly recognized U.S.D.A. rust inhibitors, antioxidants, or surfactants to obtain a lubricant suitable for particular applications and operating parameters.

(34) In particular embodiments of the invention, the lubricant for use on conveyor machinery in a food processing plant will include the following:

(35) TABLE-US-00003 CHART I (Mixture 1) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 55 74% N/A 12 cp. Polybutene Indopol H35 20% 600 81 cSc* Fatty Acid Pamolyn 100  5% 282 34 cp. Silicone Oil GE Silicone  1% N/A 350 cSc** SF96-350 Mixture N/A 100%  N/A 20 cp. *Viscosity of Indopal polybutene was measured in centiStokes at 99° C. **Viscosity of GE Silicone SF96-350 was measured in centiStokes at 25° C.

(36) TABLE-US-00004 CHART II (Mixture 2) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 55 70.5% N/A 12 cp. Polybutene Indopol H50 23.5% 750 125 cSt Fatty Acid Pamolyn 100   5% 282 34 cp. Silicone Oil GE Silicone   1% N/A 350 cSc SF96-350 Mixture N/A  100% N/A 24 cp.

(37) TABLE-US-00005 CHART III (Mixture 3) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 55 73% N/A 12 cp. Polybutene Indopol H100 20% 920 35,900*    985** Fatty Acid Pamolyn 100  5% 282 34 cp. Silicone Oil GE Silicone  2% N/A 350 cSc** SF96-350 Mixture N/A 100%  N/A 28 cp. *SUS @ 38° C. (100° F.) **SUS @ 99° C. (210° F.)

(38) TABLE-US-00006 CHART IV (Mixture 4) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 150 64.7%  N/A 150 cp. Polybutene Indopol H25  20% 610 56 cSt Fatty Acid Pamolyn 100 4.8% 282 34 cp. Silicone Oil GE Silicone .sup. 1% N/A 350 cSc** SF96-350 Rust Inhibitor S-maz 80 0.1% N/A N/A Mixture N/A 100%  N/A 156 cp.

(39) TABLE-US-00007 CHART V (Mixture 5) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 150 70.1%  N/A 150 cp. Polybutene Indopol H25  24% 610 56 cSt Fatty Acid Pamolyn 100 4.8% 282 34 cp. Silicone Oil GE Silicone .sup. 2% N/A 350 cSc** SF96-350 Rust Inhibitor S-maz 80 0.1% N/A N/A Mixture N/A 100%  N/A 20 cp.

(40) TABLE-US-00008 CHART VI (Mixture 6) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil SUS 150 87.7%  N/A 150 cp. Polybutene Parapol 950 6.3% 950 220 cSt* Fatty Acid Pamolyn 100 4.9% 282 34 cp. Silicone Oil GE Silicone .sup. 2% N/A 350 cSc** SF96-350 Rust Inhibitor S-maz 80 0.1% N/A N/A Mixture N/A 100%  N/A 74 cp. *Viscosity of Parapol was measured in Centistokes at 100° C. Parapol 950 is sold by Exxon Chemicals, P.O Box 3272, Houston, TX 17001.

(41) TABLE-US-00009 CHART VII (Mixture 7) Percent (%) Molecular Component Brand By Wt. Wt. Viscosity Mineral Oil Sontex 55 80.3% N/A 150 cp. Polybutene Parapol 950  4.7% 950 220 cSt Fatty Acid Pamolyn 100 14.0% 282 34 cp. Silicone Oil GE Silicone   1% N/A 350 cSc SF96-350 Mixture N/A  100% N/A 24 cp.

(42) Application of the electrostatically charged lubricant to the trolley having the opposite electrostatic potential tends to make the lubricant cling preferentially to metal surfaces of the trolley during the process of conveying a meat carcass through a conveyor in a meat packing plant, thereby reducing dripping from the trolley.

(43) While the preferred embodiment has been described in order to illustrate the fundamental relationships of the present invention, it should be understood that numerous variations and modifications may be made to these embodiments without departing from the teachings and concepts of the present invention. Accordingly, it should be clearly understood that the form of the present invention described above and shown in the accompanying drawings is illustrative only and is not intended to limit the scope of the invention to less than that described in the following claims.