Patent Application
20200123714
The present invention relates generally to truck and/or trailer mounted portable devices for dispensing pavement repair materials and, specifically, to such a portable device for dispensing repair materials for asphalt pavements,
In the past, as many as three vehicles were sometimes needed to repair openings and potholes in asphalt, concrete and other roadway surfaces. One vehicle provided an air compressor for use with various pneumatic repair tools which were used to dress the hole, crack or cavity to be filled. Another vehicle contained liquid asphalt tack material which would be sprayed into the dressed cavity, and a third vehicle would deliver asphalt mix material to the cavity. The asphalt would then be packed, compacted and leveled by hand to complete the repair.
U.S. Pat. No. 4,196,827, issued Apr. 8, 1980, entitled “Portable Machine For Transporting Heated Asphalt Products For Use In Repair Asphalt Pavement” shows a portable machine which was designed to incorporate all phases of the pavement repair into one mobile unit. The machine has a hopper for transporting asphalt mix, and a reservoir below the hopper having a heat source. The heat source was a propane fueled retort style heater. The reservoir contained liquid asphalt tack material. The heat source is used to heat the liquid tack material, and the tack material is used to heat the asphalt mix in the hopper by heat transfer. Asphalt tack material is also dispensed from the tack material tank by means of spray equipment connected to a discharge valve on the rear of the truck,
U.S. Pat. No. 4,944,632, issued Jul. 31, 1990, entitled “Device For Dispensing Asphalt Repair Materials”, assigned to the assignee of the present invention, shows an improved device of the same general type used for transporting asphalt repair materials for use in repairing potholes in asphalt pavements. The device has a body with a hopper compartment for transporting and dispensing asphalt mix materials. A separate tack oil tank is provided with an internal circulation system for maintaining liquid tack oils in an emulsified state. A heat transfer oil tank was located below the hopper compartment and was heated by a retort tube propane burner.
U.S. Pat. No. 5,988,935, issued Nov. 23, 21999, entitled “Asphalt Repair Apparatus With Dry, Heat Source” arid U.S. Pat. No. 6,681,761, issued Jan. 27, 2004, entitled “Exhaust Damper System For Asphalt Heating Device”, both assigned to the assignee of the present invention show additional improvements in this same basic design of asphalt repair machine. Both of these devices featured a hopper compartment which was heated by a dry radiant heat source which was heated by a propane retort tube burner.
While the above devices represented an advance in the relevant arts at the time, there is also a need in some circumstances for an asphalt repair device of this general type which utilizes some type of off-hours heating source for heating the asphalt hopper compartment of the device during on-working hours. The heat source would not be used during normal working hours when the hopper compartment is heated with its primary heat source.
Further, there exists a need for such a device which can provide supplemental heat to the hopper compartment during non-working hours which provides even and controlled heat to keep the asphalt hot during non-working hours.
There also exists a need for such au asphalt repair device which features a supplemental heat source that safely and effectively heats the asphalt repair materials without hardening, burning or charring such materials during off-hour time periods.
The portable apparatus of the invention is used to transport heated pavement repair materials for use in repairing roadways and other traffic bearing surfaces. The device includes a body adapted to be mounted on a portable base for transporting the body to a repair site. The body has a hopper compartment with a V-shaped bottom wall for transporting asphalt mix material and a generally V-shaped heating chamber located below the hopper compartment. The V-shaped bottom wall of the hopper compartment defines an upper extent of the heating chamber. An anger or screw conveyor is mounted in the bottom of the hopper compartment for dispensing asphalt mix materials therefrom. An agitator, such as a paddle shaft, is located above the auger in the hopper compartment for agitating the hopper materials.
A primary beat source is associated with the heating chamber for heating the chamber and for transferring heat to the hopper compartment through the hopper bottom wall for heating the hopper compartment during normal working hours of the device. A supplemental heat source is located within the hopper compartment fin heating the hopper compartment during non-working hours. The supplement heat source comprises one or more electric electric heat riser tubes which extend longitudinally within an interior of the hopper compartment and which are selected to provide low density, slow heat to prevent asphalt materials within the hopper compartment from overheating and burning or cooking, or otherwise deteriorating during periods of supplemental heating.
The primary heat source can be any of the conventionally available sources, such as an LP gas heating source, a CNG gas heating source, an electric heating source or a diesel fired heating source.
In one preferred design for the device, the truck mounted hopper compartment has a front wall, a rear wall and opposing side walls, the front and rear walls defining a chamber length therebetween. A pair of electric heat riser tubes are located in a generally horizontal plane which extends between the front and rear walls above the plane of the agitator shaft, the electric heat riser tubes extending generally parallel to one another on either side of the agitator shaft for a majority of the chamber length.
The preferred electric heat riser tubes are tear drop shaped in cross section and are used to contain electric heating rods which are plugged into a 220 volt electric supply outlet located on a control panel of the truck during non-working hours. In one preferred embodiment, the heating rods are 800 watt electric rods which are selected to supply low density, slow heat to the electric heat riser tubes in the range from 250° F. to 275° F. to prevent asphalt materials in the hopper compartment from being overheated. The electric heating rods can be, for example, approximately 96 inches long where the riser tubes themselves are approximately 108 inches long.
In the preferred configuration to be more fully described, the electric heat riser tubes comprise an external plate-like structure with opposing longitudinal sides which diverge from an upper apex downwardly toward a curved bottom region of the heat tubes. The electric heat riser tubes are installed approximately two thirds of the way up an internal height of the hopper compartment and are effective to keep asphalt materials in the hopper compartment hot during non-working hours of the device when plugged into a 220 volt electric supply outlet. The electric heating rods in the riser tubes are preferably provided with a built-in thermocouple,
In one preferred form of the truck mounted device, the V-shaped bottom wall of the hopper compartment forms an upper, uninsulated common wall of the heating chamber, the heating chamber having an insulated bottom wall and insulated side walls. The heating chamber can be a sealed heat transfer oil chamber and the heat transfer oil chamber can be heated by one of the primary heat sources of the device.
A method of repairing a pothole in an asphalt pavement using the previously described device is also shown. A body is provided on a portable base for transporting the body to a repair site. The body is equipped with a hopper compartment with a V-shaped bottom wall for transporting asphalt mix materials and a generally V-shaped heating chamber located below the hopper compartment, the V-shaped bottom wail of the hopper compartment defining an upper extent of the heating chamber. A screw conveyor, as previously described, is mounted in the bottom of the hopper compartment for dispensing asphalt mix materials. A paddle shaft is located above the screw conveyor in the hopper compartment for agitating the hopper materials.
A primary heat source is provided which is associated with the heating chamber for heating the chamber and for transferring heat to the hopper compartment through the hopper bottom wall to maintain the asphalt mix materials in a workable state during normal working hours of the machine. A supplemental heat source, as has been described, is located within the hopper compartment for heating the hopper compartment during nonworking hours. The supplement heat source includes one or more electric electric heat riser tubes which extend longitudinally within an interior of the hopper compartment and which are selected to provide low density heat to prevent asphalt materials within the hopper compartment from overheating and burning or deteriorating during periods of supplemental heating.
The described device is used to dispense asphalt mix materials from the hopper compartment to fill and repair a pothole during normal working hours of the device while being heated by the primary heat source. The primary heat source for the hopper compartment is turned off during non-working hours and the supplemental heat source is turned on and used to heat asphalt materials in the hopper compartment during the non-working hours to keep the asphalt hot.
Additional objects, features and advantages will be apparent from the written description which follows.
The present invention provides an improved pothole patcher design which meets the foregoing objectives. The invention described herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting examples which are illustrated in the accompanying drawing and detailed in the following description. Descriptions of well-known components and processes and manufacturing techniques are omitted so as to not unnecessarily obscure the workings of the invention. The examples used herein are intended merely to facilitate an understanding of ways in which the invention herein may be practiced and to further enable those of skill in the art to practice the invention. Accordingly, the examples should not be construed as limiting the scope of the claimed invention.
The advantages of present invention can perhaps best be understood with reference to Applicant's prior art device which utilized a propane retort heater system as a “primary heat source” for the asphalt materials which were to be dispensed. By “primary heat source” is meant the heat source that is normally used to heat the asphalt materials in the hopper compartment during normal working hours that the device is in service repairing potholes on a roadway, for example. Accordingly, turning to
As best seen in
As shown in
In the case of the prior art device shown in FIG.'s 6 and 7, the “primary heat source” comprises a dry heat means which is associated with the heating chamber 121 for heating the chamber and for transferring heat to the hopper compartment 105 through the hopper bottom wall 119 to maintain the asphalt mix materials contained therein in a workable state. In the prior art device, the dry heat means comprised a pair of oppositely arranged retort tubes 133, 135 which are located within the heating chamber 121 on either side of the V-shaped bottom wall of the hopper. The retort tubes are each heated by a 150,000 btu retort tube propane burner. The burners are thermostatically controlled and regulated at 10 psi. The burners utilized commercially available ignition systems, such as a 12 volt DC electronic igniter. The gas burner is preferably provided with a safety shut-off on loss of flame or excessive temperature. The commercially available burner, ignition and safety shut-off system for the retort tubes can be obtained from H. D. Industries, Inc., of Jacksonville, Tex. The commercially available burner has two stages, ignites on 10 ounces of pressure and operates at 10 psi. The retort tubes are used to supply dry, radiant heat to the bottom wall of the hopper compartment.
As shown in
Each U-shaped retort tube includes a first leg 145 (
As briefly mentioned, the asphalt dispensing apparatus shown in FIG.'s 6 and 74, as well as the is device of the invention, is most preferably intended to be truck mounted on the bed of a suitable road worthy vehicle. The device could also be a trailer mounted portable device with the device being mounted on the bed of a trailer which would be hauled by a suitable vehicle. The truck or trailer would serve as a portable base for transporting the body 101 to a repair site for repairing a pothole in an asphalt pavement.
While the device shown in FIG.'s 6 and 7 works well for its intended purpose, there are some situations in which it is desirable to have a “supplemental heating source” for providing heat during non-working hours of the machine. As has been explained, the previously described “primary heat source” is the heat source that is normally used to heat the asphalt materials in the hopper compartment during normal working hours that the device is in service repairing potholes on a roadway, for example. During non-working hours, for example at night, the primary heat source is shut off and is inactive. In some situations, for example, colder climates or in wintertime use, it may be desirable to provide supplemental heat to the hopper compartment in order to keep the asphalt materials hot and to keep them from seizing up. The present invention is directed to improvements in the heating system used to heat the hopper compartment for maintaining the asphalt repair materials contained therein in a workable state during “non-working hours.”
Turning now to FIG's 1 and 2, there is shown the improved asphalt dispensing apparatus of the invention, designated generally as 201. The device shown in FIG.'s 1 and 2 has many of the same general components as the previously described prior art device of FIG.'s 3 and 4, and the corresponding parts will be numbered similarly, generally incremented by 100 in each case. Thus, the improved device includes a body 203 which is adapted to be mounted on a portable base. The body has a hopper compartment 205 (
As shown in FIG.'s 1 and 2, the body 203 of the portable device is also equipped with an auger or screw conveyor 227 which is mounted in the bottom region 229 of the hopper which forms a trough-like opening extending longitudinally along the bottom wall thereof. As previously described, the screw conveyor 227 is used to dispense asphalt mix materials contained within the hopper. An agitator means, such as paddle shaft 231 is located above the screw conveyor 227 in the hopper compartment 215 for agitating the hopper materials contained therein. The screw conveyor can be, for example, 10 feet long by 6 inches diameter progressive screw conveyor with hard surfaced flights welded continuously on 2 inch scheduled 80 steel pipe and is ball bearing mounted. The conveyor is driven by a 9200 in.lb. torque variable speed hydraulic motor with forward and reverse. It is used to feed a delivery chute (not shown) with 120° of pivot. The paddle shaft 231 is used to break up asphalt due to vibratory compaction. In one embodiment, it is a schedule 160 shaft with 12 spikes and is ball bearing mounted and driven by a 9,200 in.lb. torque variable speed hydraulic motor with forward and reverse.
The apparatus of the invention may include a separate emulsion or liquid asphalt tank (not shown) mounted on the portable base for transporting and dispensing liquid asphalt type materials used to dress a pothole prior to dispensing the asphalt mix materials from the hopper. The separate liquid asphalt tank could take the form of, for example, the tank described in issued U.S. Pat. No. 4,944,632, supra, assigned to the assignee of the present invention. That tank is provided with an internal circulation system for maintaining liquid tack oils in an emulsified state.
While the primary heat source used with the version of the asphalt dispensing machine shown in FIG's 6 and 7 was propane heated retort tubes, the primary heat source shown in the device of FIG.'s 1 and 2 is an ails-electric heat source associated with the liquid filled heating chamber 221 for heating the chamber and for transferring heat to the hopper compartment 205 through the hopper bottom wall 207. As shown in FIG.'s 1 and 2, the all-electric heat source preferably comprises a pair of oppositely arranged electric heaters 240, 242, located within the heating chamber 221 on either side of the V-shaped bottom wall of the hopper. The electric heaters are powered by an electric generator (246 in
During working hours, the 130 gallon heat transfer oil heating chamber is heated by the two 208 to 240 volt AC single phase electric resistance heaters powered by a 50 amp, 12,000 watt, PTO hydraulic driven on-board electric generator. This exemplary system is capable of heating asphalt materials from 0° to 300° F. The electric generator could also be run off an auxiliary pony motor, or the like.
The improved supplementary heat source which is used to heat the asphalt materials in the hopper compartment during non-working hours will now be described. With reference to FIG.'s 1-5, the supplement heat source comprises one or more electric electric heat riser tubes. In the preferred design, there are two electric electric heat riser tubes 248, 250 which extend longitudinally within the interior of the hopper compartment 205 and which are selected to provide “low density heat” to prevent asphalt materials within the hopper compartment from overheating and burning or deteriorating during periods of supplemental heating,
The term “low density heat” is used in the general sense that this ten n is used, for example, in the water heater industry. In other words, electric storage water heaters use electrical resistance to raise the temperature of one or more heating elements mounted inside the water tank. These elements are categorized as “low-density” or “high-density”, based on their design. The “density” refers to the amount of wattage per square inch of surface area. As an example, a heater element with 10 square inches of surface area, rated for 1,500 watts, would conduct 150 watts per square inch when in use. By comparison, a 1,500 watt element with only 7.5 square inches of surface area would be a higher density element, conducting 200 watts per square inch. Low-density elements have more surface area than high-density elements, with comparable wattage.
The terms “high-density” and “low-density” as applied to electric heating elements of the type under consideration thus simply refers to how much wattage the element uses in comparison to its surface area or its size. An element with low density uses a lower temperature to operate. A unit with higher density uses a higher temperature to operate. In the preferred embodiment to be more fully described, the electric heating rods which are inserted within the electric heat riser tubes are 220 volt electric heating rods. They each have an 800 watt rating to provide low density, slow heat to prevent the asphalt materials in the hopper compartment for cooking on the exterior surfaces of the electric heat riser tubes in use. In the example shown, the electric heat riser tubes are approximately 108 inches long and the electric heating rods are approximately 96 inches long. With this particular configuration, the 220volt electric heat riser tubes can supply low density, slow heat to the electric heat riser tubes in the range from 250° F. to 275° F. to keep the asphalt in the hopper compartment hot but without overheating the asphalt.
With reference again to
With reference now to
As perhaps best seen in
As shown in simplified fashion in
One preferred version of the asphalt dispensing machine of the invention has been described in FIG.'s 1 and 2 as having the previously described all-electric primary heating source comprised of the 220 volt electric heaters 240, 242. However, it should be apparent that the heat riser tube features of the invention could also be used in dispensing machines heated by other primary heat sources commonly used in the industry. For example, the primary heat source could be selected from the group consisting of an LP gas heating source, a CNG gas heating source, an electric heating source and a diesel fired heating source, to name several conventional sources.
The operation of the version of the asphalt dispensing apparatus of FIG.'s 1 and 2 will now be briefly described. The heat transfer oil in the heating chamber 221 is heated by the two electric 220 volt resistance heaters 240, 242, which, in turn, heat the asphalt mix in the hopper compartment 205. The heat transfer oil in the heating chamber 221 is sealed off and does not intermix with the emulsion or tack oil contained in its separate tank. At the job site, suitable hydraulic tools are connected to outputs from the hopper compartment and the emulsion tank so that repairs can be quickly accomplished. Spray equipment such as a conventional wand can be connected to a discharge valve for dispensing liquid asphalts or emulsions to seal and tack the dressed cavity. The screw conveyor 227 is then actuated to dispense asphalt mix materials from the hopper compartment 205 through the discharge chute into the cavity as required. The filled cavity can then be compacted with a hydraulic tamper to complete the job.
In addition to the previously described apparatus used in the practice of the invention, there is also provided an improved method for repairing a pothole in an asphalt pavement, comprising the steps of:
providing a body on a portable base for transporting the body to a repair site, the body being equipped with a hopper compartment with a V-shaped bottom wall for transporting asphalt mix materials and a generally V-shaped heating chamber located below the hopper compartment, the V-shaped bottom wall of the hopper compartment defining an upper extent of the heating chamber; providing a screw conveyor mounted in the bottom of the hopper compartment for dispensing asphalt mix materials therefrom;
providing a paddle shaft located above the screw conveyor in the hopper compartment for agitating the hopper materials;
providing a primary heat source associated with the heating chamber for heating the chamber and for transferring heat to the hopper compartment through the hopper bottom wall to maintain the asphalt mix materials in a workable state during normal working hours of the machine;
providing a supplemental heat source located within the hopper compartment for heating the hopper compartment during non-working hours, the supplement heat source comprising one or more electric electric heat riser tubes which extend longitudinally within an interior of the hopper compartment and which are selected to provide low density heat to prevent asphalt materials within the hopper compartment from overheating and burning or deteriorating during periods of supplemental heating;
dispensing asphalt mix materials from the hopper compartment to fill and repair a pothole during normal working hours of the device; and
turning off the primary heat source for the hopper compartment during non-working hours and turning on the supplemental heat source to heat asphalt materials in the hopper compartment during the non-working hours.
An invention has been provided with several advantages. The device is simpler in design and more economical to manufacture than some of the prior art devices of the same general type. In the case of the all-electric version of the device, the heat system utilized heats more efficiently in some outside environments. Once the electric heaters get the hopper compartment hot, it stays hot for an extended period of time. The use of the submerged electric heaters in the sealed heating chamber has been found to increase the life expectancy of an associated electric generator by 50% over prior art systems. Since the heating chamber is sealed, it is only infrequently necessary to replenish the heat transfer medium or maintain such medium. In both the all-electric machine and in other machines having alternate primary heat sources, such as LP gas, and the like, the supplemental heating system provides heat to the hopper compartment during non-working hours when the primary heat source is turned off. The described electric heating rods and heat riser tube arrangement can effectively supply low density, slow heat to the electric heat riser tubes in the range from 250° F. to 275° F. to prevent asphalt materials in the hopper compartment from being overheated during the period of time that the electric heat riser tubes are employed.
While the invention has been shown in several of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof, as described in the claims which follow.
