CONTROL SYSTEM FOR TIRE INJECTION FILLING MIXING MACHINE

Abstract

A method of controlling operation of a tire filling mixing machine, by: (a) mixing a rubber/polyurethane and a catalyst in a first mixer to form a virgin polyurethane; (b) grinding cured polyurethane core bits in a grinder; (c) mixing the virgin material and the ground material in a second mixer thereby forming a mixed flatproofing material; (d) injecting the mixed flatproofing material into a tire; (e) measuring the ratio of ground material to virgin material in the mixed flatproofing material; (f) comparing the measured ratio of ground material to virgin material to a pre-stored preferred ratio of ground material to virgin material; and (g) increasing or decreasing the relative percentages of virgin material and ground material entering the second mixer by an amount that is a fraction of the difference between the measured ratio and the pre-stored preferred ratio.

Claims

1. A method of controlling operation of a tire filling mixing machine, comprising: (a) mixing a polyurethane isocyanate and a catalyst in a first mixer to form a virgin polyurethane; (b) grinding cured polyurethane core bits in a grinder; (c) mixing the virgin polyurethane and the ground core bits in a second mixer thereby forming a mixed flatproofing material; (d) injecting the mixed flatproofing material into a tire; (e) measuring a ratio of ground core bits to virgin polyurethane in the mixed flatproofing material by (i) weighing the virgin polyurethane prior to the virgin polyurethane entering the second mixer, and (ii) weighing the ground core bits prior to the ground core bits entering the second mixer; (f) comparing the measured ratio of ground core bite bits to virgin polyurethane to a pre-stored preferred ratio of ground core bits to virgin polyurethane; and (g) increasing or decreasing relative percentages of virgin polyurethane and ground core bits entering the second mixer by an amount that is a fraction of a difference between the measured ratio and the pre-stored preferred ratio, and wherein the fraction is between % and 5%; and (h) iteratively repeating steps (f) and (g) and performing step (g) only when step (f) indicates that the measured ratio of ground core bite bits to virgin polyurethane is within a desired error range.

2. (canceled)

3. The method of claim 1, wherein the fraction is %.

4. The method of claim 1, wherein the ratio of ground core bits to virgin polyurethane in the mixed flatproofing material is measured by scales.

5. The method of claim 1, wherein the measurement is taken after the tire is filled.

6. The method of claim 1, wherein increasing or decreasing the relative percentages of virgin polyurethane and ground core bits entering the second mixer is performed by increasing or decreasing a speed of an auger in the grinder.

7. The method of claim 6, wherein the speed of the auger is adjusted by %.

8. The method of claim 1, wherein the relative percentages of virgin polyurethane and ground core bits entering the second mixer are not increased or decreased if the measured ratio of ground core bits to virgin polyurethane varies from the pre-stored preferred ratio by more than a pre-determined error percentage.

9. The method of claim 8, wherein the pre-determined error percentage is 7%.

10. The method of claim 6, further comprising: recording data into a programmable logic controller, the data comprising: (a) the measured ratio and the time at which the measured ratio was taken, and (b) the pre-stored preferred ratio, and (c) the speed of the auger and the time at which the speed of the auger was measured.

11. The method of claim 10, further comprising: transmitting the data from the programmable logic controller to a remote system operator.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0023] FIG. 1 is a flow schematic of the present system, explaining its operation.

[0024] FIG. 2A is a perspective view of the present system.

[0025] FIG. 2B is a side elevation view of the present system.

[0026] FIG. 2C is a top plan view of the present system.

[0027] FIG. 2D is a front elevation view of the present system.

[0028] FIG. 3A is an illustration of an exemplary auger for use with the present system.

[0029] FIG. 3B is a close-up illustration of the exemplary auger of FIG. 3A (showing further details of the auger).

[0030] FIG. 4A is a first data plot of the adjustments made by the present control system to the ground rubber to virgin rubber mixture to a preferred ratio. Specifically, this data plot shows the changes in the percent of ground rubber in the mixture over time.

[0031] FIG. 4B is a second data plot of the adjustments made by the present control system to the ground rubber to virgin rubber mixture to a preferred ratio. This data plot also shows the changes in the percent of ground rubber in the mixture over time.

[0032] Table 1 shows two cases of test results in which the present control system moves the mixture into its preferred ratio range within 19 passes (i.e.: 19 tires filled) (Case 1), and within 16 passes (i.e.: 16 tires filled) (Case 2).

DETAILED DESCRIPTION OF THE FIGURES

[0033] FIG. 1 is a flow schematic of the present system, explaining its operation, as follows. Tire filling system 10 comprises a first mixer 20 which receives a polyurethane into an inlet 22 and a catalyst into inlet 24. First mixer 20 mixes the polyurethane and catalyst to form a virgin polyurethane.

[0034] A grinder 30 grinds cured polyurethane core bits therein. These core bits preferably come from pre-used tires, and can optionally be any of a cured virgin polyurethane, a cured virgin polyurethane and a used polyurethane either in chunks or in granules, a cured virgin polyurethane blended with crumb rubber particles, or a blend of any of these materials. An auger 32 (FIGS. 3A and 3B) is disposed within grinder 30 for grinding the core bits down to a preferred small size. In preferred aspects, the ground core bits may have a diameter of inch or less. This small dimension can be achieved by passing the ground core bits through the auger 32 and then passing through a screen having inch holes. In preferred aspects, grinder 30 has an upper hopper 31 into which large pieces of rubber are inserted.

[0035] The ground rubber core bits from grinder 30 and the virgin polyurethane from first mixer 20 are then mixed together in second mixer 40 to form a tire flatproofing material that is then passed through an injector 50 into a tire 60. Tire 60 may be either a tubed or tubeless tire. Injector 50 may be a screw-type injector. A pump will also accompany injector 50.

[0036] FIGS. 2A to 2D illustrate further views of the present system 10 in which a control system and method of controlling operation of tire filling mixing machine 10 is provided. This method first comprises: (a) mixing the isocyanate and catalyst in first mixer 20 to form a virgin polyurethane; (b) grinding core bits in grinder 20; (c) mixing the virgin material and the ground core bits in second mixer 40 thereby forming a mixed flatproofing material; (d) injecting the mixed flatproofing material into tire 60.

[0037] Control of this method is provided by: (e) measuring the ratio of ground core bits to virgin polyurethane in the mixed flatproofing material; (f) comparing the measured ratio of ground material to virgin material to a pre-stored preferred ratio of ground material to virgin material; and (g) increasing or decreasing the relative percentages of virgin material and ground material entering the second mixer by an amount that is a fraction of the difference between the measured ratio and the pre-stored preferred ratio.

[0038] Specifically, scales are preferably provided to measure the ratio of ground material to virgin material in the mixed flatproofing material coming out of second mixer 40 (i.e.: by measuring the weight of ground rubber/polyurethane bits entering the second mixer 40 and by measuring the weight of virgin rubber/polyurethane entering the second mixer 40).

[0039] The mixing ratio measurements are preferably taken after each tire is filled. Next, as stated above, the relative percentages of virgin material and ground material entering second mixer 40 are adjusted by an amount that is a fraction of the difference between the measured ratio and the pre-stored preferred ratio. In optional embodiments, the fraction is %. As such, after perhaps 20 tires (or less) have been filed, the measured ratio will fall within a preferred range of virgin material to ground material. It is to be understood, however, that the fraction need not be % and may instead range from % to 5%.

[0040] In preferred aspects, the ratio of ground to virgin material is 65% to 60% ground material to virgin material; however, this desired ratio may vary depending upon the ambient temperature and humidity where the tire filling and curing is carried out.

[0041] In preferred embodiments, increasing or decreasing the relative percentages of virgin material and ground material entering second mixer 40 is performed by increasing or decreasing the speed of auger 32 in grinder 30. In this regard, the speed of auger 32 is preferably adjusted by % (or by some other suitable amount or within some other suitable range).

[0042] In further preferred aspects, the present system automatically avoids over-compensating by not performing adjustments when the measured ratio is determined to be an outlier (which is likely the result of a data read error). Specifically, should the measured ratio deviate from the desired ratio by more than a certain percentage (or be above or below pre-determined values), then that particular reading is ignored and not acted upon. In preferred aspects, the relative percentages of virgin material and ground material entering the second mixer are not increased or decreased if the measured ratio of ground material to virgin material varies from the pre-stored preferred ratio by more than this pre-determined error percentage. In optional preferred aspects, the pre-determined error percentage is around 7% or 8%, or the desired mixture band or range may be set between 64.5% to 65.5% (for a desired 65% ratio), or between 59.5% to 60.5% (for a desired 60% ratio). The present approach of rejecting outliers ensures that the present system does not make large adjustments as a result of data errors. This prevents the present system from over-compensating or over-adjusting.

[0043] In further aspects of the present system, data is recorded into a programmable logic controller. Such data may include: (a) the measured ratio and the time at which the measured ratio was taken, (b) the pre-stored preferred ratio, and (c) the speed of the auger and the time at which the speed of the auger was measured. This data can be transmitted from the programmable logic controller to a remote system operator so that the operator can verify that the tires meet desired requirements and track and predict material usage and ordering. In preferred aspects, the operator can gain access to the control system through a NVC App or a web address. The present system may optionally scan barcodes to track material shipments.

[0044] FIGS. 3A and 3B are illustrations of an exemplary auger for use with the present system.

[0045] In preferred aspects, sensors measure the temperature and vibration of the auger. In addition, sensors (such as an ultrasound sensor) can be added to the hopper 31 to detect the level of rubber crumb in the hopper. Should the level drop too low, the sensor(s) can be used to automatically shut down the system operation. This has the beneficial effect of preventing virgin material from being wasted when the recycled rubber crumb supply drops in the machine. Since rubber crumb is loaded into hopper 31 in bulk lots, this also ensures that the ratio of ground material to virgin material remains consistent.

[0046] FIGS. 4A and 4B are illustrations two different cases of the present control system adjusting the ground rubber to virgin mixture to within a preferred range or band of the preferred ratio, as follows. For a target value of 65%, a desirable range is set into the present control system of from 64.5% to 65.5%. As such, production within this range (64.5% to 65.5%) is deemed to be acceptable and desired. Outlier reject values of 62% and 68% are also pre-set into the present control system. As such, should a measured value fall below 62% or above 68%, it is simply ignored.

[0047] In FIG. 4A, the operator/customer desires that 65% of the mixture is ground rubber. A first measurement [1] is taken after a first tire is filled. Since measurement [1] falls above 62%, adjustment is made to the mixture (e.g.: by increasing the auger speed by 1.005 times). A second measurement [2] is taken after the second tire is filled. Measurement [2] is closer to the preferred (i.e.: 64.5% to 65.5%) range and again the auger speed will be increased by 1.005 times. This pattern is repeated after each of tires [3], [4], [5] and [6]. Eventually, at measurement [7] (i.e.: after the 7.sup.th tire has been filled, no further adjustments are necessary. Instead, measurements are simply taken after each of tires [8], [9] and [10] to ensure the measured values are still within the acceptable ranges.

[0048] Another example is illustrated in FIG. 4B. A first measurement [1] is taken after a first tire is filled. Since measurement [1] falls above 65.5%, adjustment is made to the mixture (e.g.: by decreasing the auger speed by 0.995 times). A second measurement [2] is taken after the second tire is filled. Measurement [2] is closer to the preferred range (i.e.: 64.5% to 65.5%) and again the auger speed will be decreased by 0.995 times. This pattern is repeated after measurement [3] is taken. Next, however, an anomalous result [4] is measured. Since measurement [4] is above outlier limit 68%, it is simply ignored, and no action is taken. Next, measurements [5] and [6] are taken with adjustments being made to the mixture after each measurement. Eventually, at measurement [7] (i.e.: after the 7.sup.th tire has been filled, no further adjustments are necessary. Instead, measurements are simply taken after each of tires [8], [9] and [10] to ensure the measured values are still within the acceptable ranges.

[0049] It is to be understood that the values in FIGS. 4A and 4B are merely example values to illustrate the present inventive concepts. Different percentage values may be used for the desired mixture percentage, and for the acceptable band or range (around the desired mixture percentage) in which no corrective adjustment are taken. In addition, different percentage values may be used for the outlier values (above which and below which the measured ratio data is simply ignored). In the regions between the outlier values and the preferred range, the system continuously and automatically adjusts the mixture to slowly move it into the preferred range.

[0050] Table 1 shows two cases of experimental test results in which the control system moves the mixture into its preferred ratio range within 19 passes (i.e.: 19 tires filled) (Case 1), and within 16 passes (i.e.: 16 tires filled) (Case 2). The numbers in Table 1 do not correspond to those in FIGS. 4A and 4B since 4A and 4B only show a theoretical overview of two cases of system operation.

[0051] Lastly, the present system also optionally measures the ratio of rubber/polyurethane to catalyst in the first mixer 10 as well. This measured ratio is then compared to a pre-stored desired ratio, with the present control system provide continuous adjustment to adjust the rubber to catalyst ratio in the mixer (similar to how the ground rubber to virgin rubber amounts are adjusted in the second mixer).