Mobile asphalt plant

Abstract

A mobile asphalt plant for producing asphalt includes a heating unit, a container unit, a plurality of augers, and an injector. The heating unit includes one or more heaters to generate heated gas, a tank to hold heat transfer oil, and one or more first plenum tubes extending from the heaters to within the tank. The first plenum tubes transport the heated gas to the tank to heat the heat transfer oil. The container unit includes a hopper to receive the aggregate material and one or more second plenum tubes extending from the one or more first plenum tubes and extending within the hopper. The second plenum tubes transport the heated gas from the first plenum tubes to heat the aggregate material. The augers are arranged as a series of augers, with a first one of the augers receiving the aggregate material from the hopper. Each of the augers conveys the aggregate material to a next one of the augers. Each of the augers heats the aggregate material using the heat transfer oil from the tank. The injector is connected to one of the augers and injects asphalt oil into the aggregate material to produce asphalt.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application No. 63 / 129,201 filed Dec. 22, 2020, the contents of which are incorporated by reference herein in its entirety.FIELD OF THE INVENTION[0002]The invention relates to an apparatus used to produce asphalt, and in particular, to a mobile asphalt plant.BACKGROUND OF THE INVENTION[0003]Asphalt is a viscous or semi-solid substance that is commonly used in road construction. The main ingredients for producing asphalt are aggregate material (such as gravel) and asphalt oil. Typically, the production process requires that the gravel and asphalt oil must first be heated to a temperature of greater than 300° F. before being mixed together. An immense amount of heat is required to heat the gravel from ambient temperature to the required mix temperature. The specific heat for basalt rock (one of components of gravel) is 0.2 BTU / lb ° F. For example, at 100% efficiency, it would ta...

AI Technical Summary

Benefits of technology

The mobile asphalt plant can be used in low temperatures, even with gravel in the hopper. If there are frozen lumps in the gravel, the plant can slow down the process to defrost the gravel before heating it up to the final mixing temperature.

Problems solved by technology

An immense amount of heat is required to heat the gravel from ambient temperature to the required mix temperature.

Although this may be effective in heating the gravel, the flue gases are able to leave the drum unimpeded, with most of the heat being lost.

The escaping flue gases leave as wasted heat, resulting in higher operating costs, increased greenhouse gas emissions, and poor efficiency.

Another challenge facing asphalt plants is that care must be taken when operating in below-freezing temperatures.

Conventional asphalt plants cannot accommodate gravel that has been frozen into lumps.

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