Patent Application
20210108377
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 having a separate tank for dispensing asphalt emulsions as 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. 4,944,632, 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 type used for transporting asphalt repair materials for use in repairing potholes in asphalt pavements. This device was a portable machine designed to incorporate all phases of the pavement repair into one mobile unit. The device had a body with a hopper compartment for transporting and dispensing asphalt mix materials. A heat transfer oil tank was located below the hopper compartment and was heated by a retort tube propane burner. A separate emulsion oil/tack material tank was provided with an internal circulation system to assist in maintaining liquid emulsion oils in an emulsified state. Emulsion oils or asphalt tack materials were dispensed from the emulsion oil tank by means of spray equipment connected to a discharge valve on the rear of the truck.
U.S. Pat. No. 5,988,935, issued Nov. 23, 21999, entitled “Asphalt Repair Apparatus With Dry, Heat Source” and 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, although not specially dealing with the emulsion oil tank.
In spite of these improvements, a problem sometimes occurs with separation of the emulsion oils contained in the separate emulsion oil tank. These oils are generally petroleum and animal fat products that are emulsified. Most such oils are intended for immediate use or otherwise the water content of the oil separates from the base material. As a result, one of the major problems that all municipalities have with emulsion oils is that about 72 hours after purchase, the emulsion oil begins to separate. This causes the emulsion pump and associated lines to stop-up and allows sludge build-up in the emulsion tank. Previously, the emulsion oils were remixed for use by using the spray applicator pump to recirculate the materials within the tank, or the materials were manually remixed. Both methods were inefficient and time consuming. Additionally, operators sometimes failed to run the pump system where keeping it running would have solved the emulsion separation problem.
A need exists, therefore, for an improved method and apparatus for dispensing emulsion oil which prevents phase separation of the emulsion oil materials for extended periods of time. There also exists a need for such an emulsion delivery system which would be automatically actuated at the time the operator starts the emulsion pump, eliminating operator error or poor application practices.
There also exists a need for such an emulsion delivery system which is relatively simple in design and economical to manufacture and which is reliable in operation in a variety of temperatures and weather conditions.
The present invention deals with improvements to an emulsion oil system for a pothole repair apparatus of the type used to repair potholes on asphalt roadways and other traffic bearing surfaces. The emulsion oil system could be adapted to any number of asphalt transport vehicles. One preferred vehicle of this type 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 auger 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.
An emulsion oil tank is mounted on the vehicle in proximity to the hopper compartment. The emulsion oil tank has a bottom wall, a top wall and interconnecting sidewalls which together define a closed interior having a bottom region and a top region, respectively. The closed interior is supplied with a preselected level of emulsion oil which comprises a liquid-liquid emulsion. A heat exchanger is located within the emulsion oil tank for heating the emulsion oil to thereby assist in maintaining the emulsion oil in a liquid state.
The emulsion oil tank includes an emulsion pump assembly as one integral component. The emulsion pump assembly includes an emulsion pump having an inlet conduit for collecting liquid from the bottom portion of the emulsion oil tank and an outlet conduit leading to a selector valve, the selector valve being connected to a spray wand used for spraying emulsion oil onto a road surface to be repaired. The selector valve is operable between a spray on position and a spray off position. The selector valve also includes a recirculation conduit for recirculating emulsion oil back to a top portion of the emulsion oil tank when the valve is moved from the spray on to the spray off position.
An emulsion rejuvenator assembly is also located on the emulsion tank. The emulsion rejuvenator has an auger section with an auger blade vertically mounted in a support cage located within the interior of the emulsion oil tank. The emulsion rejuvenator has an auger motor for turning the auger blade when the motor is switched from an off state to an on state. Actuation of the auger blade serves to agitate emulsion oil in the tank to prevent separation of the emulsion oils contained therein.
A controller is used to supply a control signal simultaneously to both the emulsion pump and to the emulsion rejuvenator motor to power the same on and off simultaneously. In this way, powering the emulsion pump motor causes emulsion oil to be pumped from the pump inlet to the pump outlet and to the selector valve and from the selector valve to the spray wand to be dispensed by the spray wand when the spray wand is in the spray on position and back to the emulsion oil tank when the spray wand is in the spray off position. The simultaneous actuation of the rejuvenator motor causes the auger blade to move to further agitate the emulsion oil within the emulsion oil tank.
The controller can be a controller selected from among the group consisting of hydraulic controllers, electric controllers and pneumatic controllers, for example.
In one preferred form of the invention, the controller is a hydraulic controller. The control system uses a hydraulic valve body for supplying a flow of hydraulic fluid simultaneously to both the emulsion pump and to the emulsion rejuvenator motor to power the same on and off simultaneously. As has been described, powering the emulsion pump motor causes emulsion oil to be pumped from the pump inlet to the pump outlet and to the selector valve and from the selector valve to the spray wand to be dispensed by the spray wand when the spray wand is in the spray on position and back to the emulsion oil tank when the spray wand is in the spray off position. Actuation of the hydraulic valve body causes a hydraulic fluid flow to be partially diverted through a hydraulic flow controller to the auger motor of the emulsion rejuvenator assembly. The simultaneous actuation of the rejuvenator motor causes the auger blade to move to further agitate the emulsion oil within the emulsion oil tank.
A method is also shown for repairing a pothole in an asphalt pavement using an apparatus of the type previously described. Emulsion oil is dispensed from the emulsion oil tank through the hand held spray wand onto the pothole to be repaired in order to prepare the surface thereof. As has been described, powering the emulsion pump motor causes emulsion oil to be pumped from the pump inlet to the pump outlet and to the selector valve and from the selector valve to the spray wand to be dispensed by the spray wand when the spray wand is in the spray on position and back to the emulsion oil tank when the spray wand is in the spray off position. The simultaneous actuation of the rejuvenator motor causes the auger blade to move to further agitate the emulsion oil within the emulsion oil tank to prevent separation of the phases of the emulsion. Asphalt mix repair materials are also dispensed from the hopper compartment to fill and repair the pothole.
Additional objects, features and advantages will be apparent from the written description which follows.
The present invention provides a pothole patcher which meets the foregoing described objectives. Problems relating to separation of the oil emulsion in the emulsion oil tank are prevented with the addition of the new emulsion oil rejuvenator system. 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 emulsion oil system of the invention which will be described in detail can be adapted for use with various asphalt repair vehicles such as truck mounted systems, skids, trailers and dump body mounts. The invention will be described herein with respect to a truck mounted system of the type sold commercially as the Pro-Patch™ Pot Hole Patcher by H.D. Industries, Inc., of Jacksonville, Tex. This truck mounted system is capable of making permanent asphalt repairs under a variety of weather conditions and can transport hot or cold asphalt pre-mix material as well as emulsions and tack oils at controlled heated temperatures. Typical systems are provided as 3-6 cubic yard hoppers. Heating systems include dry heat or heat transfer oil. Heating sources include LP gas, CNG, diesel or all electric heat with an on-board generator.
“Asphalt” is generally defined as the residual material obtained from the distillation of asphalt-based petroleum. Chemically, asphalts are complex aggregations of rather large aliphatic and cyclic hydrocarbon molecules. Asphaltic mixtures are comprised of mineral aggregate and bituminous constituents and are widely used in the road construction industry. The major types of asphaltic mixtures are used today in highway construction and maintenance include: hot mixes; cut-backs; anionic emulsions; and cationic emulsions. Hot mix asphalts are used extensively in main highway construction where greater durability is required. These asphalts are characterized by a high asphaltene content making them very hard and resistant to chemical decomposition. Cut-back asphalts are formed by the use of an inexpensive petroleum solvent which along with the asphalt is mixed with the aggregate. The solvent evaporates leaving the asphalt binder in use. Generally, light petroleum oils or napthas are used as solvents.
The two final forms of commonly used asphalts include anionic emulsions and cationic emulsions. As their name implies, such emulsions are formed by the use of anionic or cationic emulsifiers for forming an oil-in-water emulsion which can be combined with aggregate for use in the road construction industry. Another definition of these materials is that asphalt emulsions are a type of liquid cement that is combined with water and an emulsifying agent. The emulsifying agent keeps the asphalt molecules together, which greatly improves the asphalt's binding properties. Emulsions are environmentally safe, energy efficient and cost effective way to do asphalt repair.
“Aggregate” used in road construction will be understood to include various mineral materials such as sand, rock, or the like, typically native to the localities where the roads are being built. For example, limestone, dolemite, silica, sedimentary, metamorphic, or igneous rocks of various other kinds regularly are used in road building.
In summary, in the discussion which follows, “asphalt mix” materials will be taken to mean pre-mix or aggregate hot or cold mix asphalt and asphalt aggregate. The term “liquid asphalt emulsion” or “emulsion oil” will be taken to mean asphaltic cements, liquid asphalts, tack oils and asphalt emulsions of the type carried in a separate emulsion oil tank. as will be described.
As has been mentioned, the base vehicle shown in
The screw conveyor 19 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, in one case, 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 22 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.
As those skilled in the relevant arts will appreciate, any of a number of different heating systems can be used to heat the hopper compartment by transferring heat to the bottom V-shaped wall of the hopper compartment for maintaining the asphalt repair materials contained therein in a workable state. These heating systems include LP gas, CNC gas, diesel-fired and all electric truck mounted units. These heat sources may be used for example in either dry heat systems or heat transfer oil systems and are all commercially available. In the case of the dry heat system, for example, a pair of oppositely arranged retort tubes are located within the heating chamber formed 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 utilize 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. Each retort tube forms a single pass loop which has a burner installed at one extent thereof and which communicates with an exhaust conduit such as an exhaust stack at an opposite extent thereof. The dry heat system is described in detail in Applicant's issued U.S. Pat. No. 5,988,935, issued Nov. 23, 1999.
The foregoing description is intended to explain the general environment of the present invention in terms of a commercially available asphalt dispensing device presently available in the marketplace. The invention, however, deals with the emulsion tank which is used to dispense emulsion oils to the road repair site.
Thus in
The separate liquid asphalt tank could take the form of, for example, the tank described in issued U.S. Pat. No. 4,944,632, issued Jul. 31, 1990, supra, and assigned to the assignee of the present invention. That tank is provided with an internal circulation system for maintaining liquid emulsion oils in an emulsified state. In one preferred form, that particular emulsion tank has an 80 gallon capacity and is double steel jacketed with 2″ of insulation. During working hours, a heat transfer system is used which is capable of heating emulsion oil from 0° to 150° F., using the truck engine coolant system as the heat source.
With reference now primarily to
Some type of primary heat transfer apparatus is also located within the tank 21 to heat the emulsion oil to thereby maintain the emulsion oil in a liquid state. To take one example, the heat transfer system can include an internally submerged retort tube (51 in
Turning now to
An emulsion rejuvenator assembly (designated generally as 57) is located on the emulsion tank including a rejuvenator motor 60. The emulsion rejuvenator has an auger section with an auger blade 59 vertically mounted in a support cage 61 located within the interior of the emulsion oil tank. Actuation of the auger blade serves to agitate emulsion oil in the tank to prevent separation of the emulsion oils contained therein. The rejuvenator motor 60 turns the auger blade 59 when the motor is switched from an off state to an on state.
A controller is used to supply a control signal simultaneously to both the emulsion pump 39 and to the emulsion rejuvenator motor 60 to power the same on and off simultaneously. In this way, powering the emulsion pump motor 39 causes emulsion oil to be pumped from the pump inlet to the pump outlet and to the selector valve 47 and from the selector valve 47 to the spray wand (65 in
As will be apparent from the description which follows, the controller can be a controller selected from among the group consisting of hydraulic controllers, electric controllers and pneumatic controllers. In other words, the rejuvenator motor can be hydraulic, electric or air operated.
In one preferred form of the invention, the controller is a hydraulic controller as shown in
The operation of the asphalt dispensing apparatus of the invention will now be briefly described. Asphalt contained in the hopper region (17 in
An invention has been provided with several advantages. The device is simpler in design and economical to manufacture. The improved emulsion oil tank includes a special controller which automatically actuates the rejuvenator motor and auger whenever the selector valve is turned to supply emulsion oil to the spray wand. This ensures that the emulsion oils in the emulsion oil tank will be kept in the emulsified state and prevent separation of the respective emulsion components. Without the rejuvenator system of the invention, emulsion oils tend to begin to separate within about 72 hours after purchase. Separation of the components of the emulsion causes the emulsion pump and associated circulation lines to stop-up, as well as allowing the build-up of sludge in the emulsion tank. The rejuvenator system which has been described has been found to reduce this problem on the order of about 95 percent.
While the invention has been shown in only one 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.
