What do Rabble Arms actually do?
In the context of hearth furnaces, "metal rabble arms" refer to a type of cast metal pole-like propellers attached to a central spine shaft that are used to move and agitate the material being processed inside the furnace. These cylinder funnel-looking hearth furnaces are used for a variety of industrial processes such as refining, smelting, and heat treating of metals.
The metal rabble arms are typically long, sturdy cast metal rods or arms that are inserted into the furnace and used to stir or rake the material being heated. The arms are usually made of heat-resistant materials such as steel, specifically in the harder alloys like HK and HP, which contain alloys like chromium and nickel.
Our rabble arms have a socket end that gets inserted in the furnaces center shaft. These sockets heads are either part of the original pattern or are welded on, as shown below. This socket also is equipped with an air hole venting system where cool air can be forced in the rabble arm to help cool the arm and prevent warping.
Therma-fab welding a socket head to a cast metal hearth furnace rabble arm.
The purpose of the rabble arms is to ensure that the material being heated is evenly mixed and that any impurities or gases are removed from the metal. They also help to prevent the material from sticking to the furnace walls or floor, which could cause blockages and impede the heating process.
Rabble arms also have rabble teeth attached to the underside of the pole-like arm. The square teeth or scrappers have a comb-like pattern that help stirs up the material beneath it. Our rabble teeth often have an angular shape (in or out) that help stir the materials inward and outward as it travels down the furnace, helping to evenly distribute the materials on the hearth and prevent them from sticking together.
Therma-Fab installing a rabble tooth or scraper on the track on a rabble arm
Overall, metal rabble arms are an important component of many hearth furnaces, allowing for efficient and effective processing of various types of metals.
Rabble arms are an important component of rotary hearth systems used in various industries, including the iron and steel industry. These systems are used for heating and processing materials such as iron ore, pellets, coal, and other raw materials, producing products like activated carbon, which has thousand of uses.
The rabble arms in a rotary hearth system are essentially rotating arms revolving around a center spine shaft that are used to move and mix the materials in the hearth. They are typically equipped with paddles, often called teeth or scrapers, that help to evenly distribute the materials on the hearth and prevent them from sticking together.
The rotary hearth system operates by slowly rotating the hearth while the rabble arms move the materials across the surface. This movement helps to ensure that the materials are evenly heated and processed, resulting in a more consistent and high-quality end product.
The design of the rabble arms in a rotary hearth system can vary depending on the specific application and the type of materials being processed. Some systems may use multiple sets of rabble arms, typically 5 arms per layer, to ensure maximum efficiency and uniformity, as shown below.
