Circulation Heaters also known as "in line heaters" use steel, stainless steel, and titanium in many applications. Lube oil and waste oil applications often use steel for circulation heaters as it is fairly inexpensive compared to stainless steel counterpart. Water circulation heaters are made with stainless steel because of its anti-corrosive qualities. Both applications involve using a pump that flows the liquid through a closed pipe circuit (IE. water or glycol solution) that is reheated. A major consideration for this application is viscosity. Heat that is generated by the electric heater allows the liquid to be viscous enough to pass through the circuit of pipes. Circulation heaters come in a range of watt densities that are specifically designed for the medium that is heated. The required wattage to heat the oil or water is highly correlated to the flow rate (in GPM). The oil or water enters through an inlet (the inlet closest to the flange heater) and gets heat applied to it as it flows within a vessel chamber and exits the outlet nozzle (or flange) where it circulates throughout the piping circuit. Insulation is often required for vessels in order to preserve the heat to be applied within the vessel. Efficient heat application can often reduce unnecessary costs through heat loss. Digital thermocouple probes or RTDs, can be used with the electric heaters to maintain the oil or water at the preferred temperature. Many applications use liquids with low flash point and, require explosion proof housing (NEMA 7) to avoid potential mishaps.
Other useful features found with electric circulation heaters are drain valves. They can be installed in any location on the vessel and allow for easy maintenance of the heater. The water or oil can be purged through the drain valve allowing for maintenance on the elements. Calcium deposits and other residue can be found on elements and should be cleaned several times a month. Circulation heaters also come with the choice of horizontal or vertical mounting depending on your application. Skid mounted vessels are used in oil heating industries that require mobility.
WATTCO™ heaters are also available in moisture resistant terminal boxes or explosion proof terminal boxes for hazardous environments. WATTCO™ Circulation heaters are an exceptional choice for heating process liquids, non-corrosive to the materials of construction. Circulation gas heaters are also used when heating closed loop systems that require high temperatures of up to 1000 deg F. These applications use large flange heating vessels that contain the gas and heat it up in containment most efficiently requiring low maintenance and excellent heat transfer.
Oil and Gas companies have specifically used circulation heaters to assist them in the process of modifying viscosity levels of their heating oils. Crude oil enters an inlet of the vessel at a cool temperature and exits the outlet at a temperature more convenient for flow as it travels from one end of the transport pipe to the other. Hydraulic fluid can also be heated using this electric heater for heat transfer purposes, and to resist cooler climates as winter temperatures need to be avoided. Immersion heaters are widely used in a variety of industries particularly the oil and pipeline sector for several different purposes. These industrial heaters are specifically designed so that oil, water, viscous materials, gases, solvents and other different process mixtures can be heated in direct contact with each other. This allows the heat to be generated within a single enclosure or solution, and so hundred percent efficiency can be achieved.