Patent Application
20060075608
This invention relates to an improved technique for controlling the flow of cotton in a cotton gin.
Modern cotton gins are set up to receive and disintegrate cotton modules to produce a stream of cotton which is delivered through conventional cotton handling equipment to one or more gin stands where fibers and seed are separated. To operate gin stands in an optimum manner, it is desirable to deliver enough raw cotton so the gin stands are operating at a maximum throughput. Conventional cotton gins are equipped with a feed controller receiving raw cotton from the module feeder. The feed controller acts as a surge tank to accumulate raw cotton when too much cotton is being delivered from the module feeder to the gin stands, as determined in one fashion or other.
Conventional cotton gins are also equipped with an overflow bin that receives raw cotton delivered toward the gin stands but which cannot be immediately handled by the gin stands. Raw cotton accumulating in the overflow bin is recycled back into a distribution conveyor delivering raw cotton to the gin stands. It has been attempted in the prior art to control cotton flow to provide high and low level sensors in the overflow bin and use a feedback loop to control the module feeder. In such arrangements, the module feeder is stopped when the high level sensor is tripped and the module feeder is started or speeded up when the low level sensor is tripped. By the use of a feed controller and an overflow bin having high and low level sensors, this prior art approach has improved the average production rate of gin stands as compared to the situation where cotton flow is controlled by a human operator.
Disclosures of interest relative to this invention are found in U.S. Pat. Nos. 3,495,303; 4,776,066 and 5,222,675.
In this invention, the flow of cotton through a cotton gin is controlled, at least in part, by a cotton flow modification system receiving inputs from a multiplicity of cotton level sensors in the overflow bin. The overflow bin is provided with an upper sensor, a lower sensor and at least one intermediate sensor. When the lower sensor and the intermediate sensor show that the level of cotton in the overflow bin is above the intermediate sensor, a control signal is generated that slows down the module feeder thereby reducing the quantity of cotton being delivered from the cotton module that is in the process of being disintegrated by the module feeder. When the intermediate sensor shows that the level of cotton in the overflow bin is below the intermediate sensor, a control signal is generated that speeds up the module feeder thereby increasing the quantity of cotton being delivered from the cotton module that is in the process of being disintegrated by the module feeder. Thus, in an optimum situation, the level of raw cotton in the overflow bin cycles above and below the intermediate sensor assuring there is always a full load of cotton in the inlets to the gin stands and thereby promoting maximum throughput through the gin stands.
The flow modification system also receives inputs from sensors in the gin stands and from the upper and lower sensors to control operation of the gin. For example, when the gin stand sensors generate a signal showing that the gin stand is not operating, the flow modification system may deliver a control signal to the module feeder to slow down the module feeder by an amount related to the capacity of the inoperative gin stand.
It is an object of this invention to provide an improved cotton feed control technique.
Another object of this invention is to provide an improved cotton feed control technique to improve the operating efficiency of gin stands in a cotton gin.
A further object of this invention is to provide an improved feed technique using a multiplicity of level sensors in an overflow bin of a cotton gin.
Another object of this invention is to provide an improved cotton gin that no longer requires a feed controller upstream of the gin stands to deliver an optimum quantity of cotton fiber to one or more gin stands.
These and other objects of this invention will become more fully apparent as this description proceeds, reference being made to the accompanying drawings and appended claims.
Referring to
The module feeder 12 may be of any suitable type, such as is shown in U.S. Pat. No. 5,222,675, and comprises a bed or platform 28 on which a cotton module 30 is placed. The bed 28 is movable in any suitable manner, such as a movable floor (not shown), a roller bed floor (not shown) or an endless chain 32 driven by an electric motor 34 so the module 30 is pushed into a series of disperser heads 36 driven by a second motor 38. The amount of cotton coming off the module 30 is a function of a variety of things, i.e. the cross-sectional size of the cotton module 30, the density of cotton in the module 30 as may be affected by the presence or absence of air pockets in the module 30 and the speed of the bed chain 32 as driven by the motor 34. It will be seen that the amount of cotton delivered from an outlet 40 of the module feeder 12 may be increased or decreased by speeding up or slowing down the chain motor 34.
The cleaner 14, stick machine 16, dryer 18 and hot air cleaner 20 are basically cleaners of one type or other and are of conventional design such as is available from Consolidated Gin Company, Lubbock, Tex. These or similar components, in various combinations and locations in the cotton flow path, remove debris such as leaves, stems, dirt and other particulate contaminants to produce raw cotton, which is here defined to mean cotton fiber and cotton seed with only minor amounts of other material that do not affect the quality of the cotton fiber delivered from the gin stands 22.
The output of the hot air cleaner 20 passes to a distributor conveyor 42 comprising part of the conduit system 26 having an outlet 44 to each gin stand 22. The outlets 44 are preferably tall vertical conduits or containers holding a quantity of raw cotton that is available for the gin stands 22 to handle. The conveyor 42 is open to the overflow bin 24 so that any raw cotton which passes over the top of the outlets 44 flows into the overflow bin 24.
The overflow bin 24 is a relatively large upright container 46 having feed rollers 48 near the bottom driven by an electric motor 50 for delivering raw cotton accumulating in the container 46 through a bypass conduit 52 to a separator 54 where the bypass stream is emptied into the distribution conveyor 42. Those skilled in the art will recognize the gin 10, as heretofore described, as being typical of modern cotton gins.
The overflow bin 24 includes a cotton flow control system 55 comprising an upper level sensor 56, a lower level sensor 58 and one or more intermediate sensors 60. The sensors 56, 58, 60 may be any suitable type level sensor used, or capable of being used, to detect the level of raw cotton in the container 46. Typically, the sensors 56, 58, 60 are electric eye type sensors such as are available commercially from Smith and Gray, Columbus, Ga. These typical sensors operate by delivering a light beam across the container 46 which, when interrupted by raw cotton in the container, is detected and determined to indicate that raw cotton is at the level of the sensor. Because of the characteristics of electric eye type sensors, falling raw cotton does not block the light beam for a sufficient time to be sensed. Typically, the sensors 56, 58, 60 each include a light source 62 on one side of the container and the sensor on the other. In the alternative, the level of cotton in the overflow bin 24 can be detected by other means, such as a switch having a low inertia actuator extending into the overflow bin 24 whereby cotton works on the actuator to trip the switch.
The sensors 56, 58, 60 are connected to a controller or cotton flow modification system or controller 64 by suitable wires 66 to provide a signal in the event the level of raw cotton in the container 46 reaches the level of the sensors 56, 58, 60. In addition, each gin stand 22 is provided with a sensor 68 detecting whether the gin stand 22 is operating. The sensors 68 are of conventional type such as is available from Smith and Gray, Columbus, Ga. The sensors 68 connect to the system 64 by suitable wires 70. The cotton flow modification system 64 makes certain decisions based on the inputs from the sensors 56, 58, 60, 68 and delivers an output through a wire 72 leading to the chain drive motor 34 to start, stop, speed up or slow down the motor 34 depending on the inputs.
The flow modification system 64 accordingly includes a microprocessor which operates on certain rules of logic. The preferred rules of operation may be summarized as follows. When raw cotton does not cover the lower sensor 58, the signals to the chain drive motor 34 call for normal operating speed, regardless of whether one or more of the gin stand sensors 68 signal that the gin stands 22 are not operating. In the event the lower sensor 58 is covered by raw cotton, when one of the gin stand sensors 68 signals that its gin stand has become inoperative, a signal is generated by the system 64 and delivered through the wire 72 to reduce the production of cotton from the module feeder by the ratio of the down gin stand capacity to the total gin stand capacity. For example, if two gin stands of equal capacity are in a particular gin and one goes down, the signal delivered through the wire 72 would reduce cotton production by the module feeder by one half.
Considerably more judgment and experimentation is required to optimize cotton flow to the gin stands 22 when the intermediate sensor 60 is covered with cotton. An important factor in the following criteria is the size of the overflow container 46 relative to the capacity of the gin stands 22. The normal situation is that the overflow container 46 is relatively small compared to the gin stand capacity. For example, a two stand gin will have a typical capability of ginning thirty bales an hour which is on the order of 15,000-18,000 pounds of cotton fiber per hour and the overflow bin might contain three hundred pounds of fiber and seed. Thus, in a typical situation, the reductions in speed of the chain bed motor 34 are of short duration. Preferably, the feed rate of the chain motor 34 is decreased by a considerable amount for a short period of time, for example a thirty five percent reduction for ten seconds followed by resumption at normal operating speed. If the intermediate sensor 60 is still covered after the resumption of normal operating speed, the system 64 will signal a second slow down.
When the upper sensor 56 detects a cotton level, it means the overflow bin 24 is full. Thus, a signal is generated to severely reduce or stop the feed rate of the module feeder 12. A preferred technique is to stop the module feeder for five seconds and then restart the chain motor 34 at a large percentage of its normal rate, e.g. half or two-thirds for a short restart period of preferably about ten seconds. If one of the gin stand sensors 68 detects that the gin stand 22 is down during the restart of the module feeder 12, the feed rate is further reduced by the pro-rata effect of the gin stand that is out. For example, with two gin stands 22, the already reduced feed rate of the motor 34 is reduced by half. If, during the restart period of the chain motor 34, the gin stand 22 that was detected to be out remains out, the chain motor 34 is driven at fifty percent of its normal rate. If, after the restart period of the chain motor 34, the gin stand 22 heretofore out is detected to be operating again, the chain motor 34 is signaled to operate at normal speed.
It will be apparent that the details of the logic used to manipulate the chain motor 34 is subject to wide variation, depending on the size of the overflow container 46, the operating characteristics of the module feeder 12 and other variables of a particular cotton gin.
Referring to
The cotton gin 12 is of unusual design because there is no conventional feed controller downstream of the module feeder 12 and upstream of the gin stands 22, i.e. between the module feeder 12 and the gin stands 22. A feed controller is similar to an overflow bin in the sense that it comprises a surge tank allowing the accumulation of cotton upstream of the gin stands thereby keeping the gin stands more-or-less loaded with cotton ready to the ginned. A prototype of this invention has proved successful, with no upstream feed controller, when using a module feeder of applicant's assignee. Hourly throughput through the prototype has been 4-5% greater than the same gin using a manually controlled upstream feed controller to keep the gin stands 22 loaded with raw cotton.
Referring to
The module feeder 102 may be of any suitable type and comprises a bed or platform 120 on which a cotton module 122 is placed. The bed 120 typically comprises a movable floor (not shown), a roller bed (not shown) or an endless chain 124 driven by an electric motor 126 so the module 122 is pushed into a series of disperser heads 128 driven by a second motor 130. The amount of cotton coming off the module 122 is variable, as previously explained. In the embodiment of
The flow controller 104 includes a sizeable vertical container 132 having a pair of feed rollers 134 near the bottom driven by an electric motor 136. As will be explained hereinafter, the motor 136 is sped up (is sped up correct, or is speeded up?), or slowed down, to control cotton flow to the gin stands 114.
The cleaner 106, stick machine 108, dryer 110 and hot air cleaner 112 are basically cleaners of one type or other and are of conventional design such as is available from Consolidated Gin Company, Lubbock, Tex.
The output of the hot air cleaner 112 passes to a distributor conveyor 138 comprising part of the conduit system 118 having an outlet 140 to each gin stand 114. The outlets 140 are preferably tall vertical conduits or containers holding a quantity of raw cotton that is available for the gin stands 114 to handle. The conveyor 138 is open to the overflow bin 116 so that any raw cotton which passes over the top of the outlets 140 flows into the overflow bin 116.
The overflow bin 116 is a relatively large upright container 142 having feed rollers 144 near the bottom driven by an electric motor 146 for delivering raw cotton accumulating in the container 142 through a bypass conduit 148 to a separator 150 where the bypass stream is emptied into the distribution conveyor 138.
The overflow bin 116 includes a cotton flow controller 151 comprising a lower level sensor 152, an upper level sensor 154 and one or more intermediate sensors 156. The sensors 152, 154, 156 may be any suitable type level sensor used, or capable of being used, to detect the level of raw cotton in the container 142. Typically, the sensors 152, 154, 156 are electric eye type sensors such as are available commercially from Smith and Gray, Columbus, Ga. Typically, the sensors 152, 154, 156 each include a light source 158 on one side of the container and the sensor on the other. In the alternative, a more conventional type switch may be employed, incorporating an actuator in the bin 116 to trip the switch in response to contact with cotton.
The sensors 152, 154, 156 are connected to a cotton flow modification system or controller 160 by suitable wires 162 to provide a signal in the event the level of raw cotton in the container 142 reaches the level of the sensors 152, 154, 156. In addition, each gin stand 114 is provided with a sensor 164 detecting whether the gin stand 22 is operating. The sensors 164 are of conventional type such as is available from Smith and Gray of Columbus, Ga. The sensors 164 connect to the flow modification system 160 by suitable wires 166. The flow modification system 160 makes certain decisions based on the inputs from the sensors 152, 154, 156, 164 and delivers an output through a wire 168 leading to the feed roller motor 136 of the feed controller 104 to increase or decrease the amount of cotton delivered through the cleaners 106, 108, 110, 112 and the distribution conveyor 138 to the gin stands 114 depending on the inputs.
The rules of logic used by the controller 160 may be the same as operation of the controller 64 except that the flow controller 104 may be equipped with an upper level sensor 170 to slow down the chain motor 126 in the event the flow controller container 132 is completely full. In a simple and preferred version, the chain motor 126 is manipulated in the same manner as the chain motor 34, i.e. when the overflow bin 116 is low on cotton, the chain motor 126 is speeded up and when the overflow bin 116 is full of cotton, the chain motor 126 is slowed down. It will be recognized, of course, that the presence of the flow controller 104 and the control of outflow from the flow controller 104 by the motor 136 allows both the flow controller 104 and the module feeder 102 to be controlled to speed up, or slow down, cotton delivery to the gin stands 114.
Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of construction and operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.
