Opinion ID: 334540
Heading Depth: 2
Heading Rank: 1

Heading: description of the patented device

Text: 3 The patent in question, U.S. Patent No. 3,601,181, is entitled, Method and Apparatus for Purging Air from Internal Combustion Engine Cooling Systems. 3 The patented device is designed to increase the efficiency of automobile engine cooling systems. 4 The inventor of the patented device is Walter C. Avrea, a mechanic and vehicle maintenance superintendent, who holds other patents in the automotive field. From study and experimentation the inventor determined that the following performance and maintenance problems in engine cooling result, wholly or in part, from the presence of air inside the system: formation of a froth which retards heat transfer; formation of sludge, which impairs circulation of liquid coolant; oxidation of metal parts and corrosion of rubber hoses, which promote boiling; cavitation, 4 which strains, or sometimes breaks, the water pump. The inventor claims the patented device attacks these problems by purging air from the cooling system during engine operation and by preventing re-entry of air when the engine stops. 5 The invention can be made accessory to a standard radiator system. It uses a vessel called an accumulator, which serves as second liquid storage tank. The accumulator has a vent, and is mounted in the engine compartment. A tube connects the low point in the accumulator with the overflow outlet in the radiator's filler neck. Another essential component of the system is a special radiator cap, 5 with threads and gasket designed to assure a hermetic seal whose function is to prevent leakage of air into the radiator. 6 6 Upon installation, the cooling system is filled to overflowing and sufficient liquid is placed in the accumulator to cover the opening of the overflow tube. Thermal expansion of the liquid in the cooling system builds overflow pressure and causes the ejection of air, liquid and steam through the overflow tube into the accumulator. Expelled gaseous matter bubbles to the top of the liquid in the vented accumulator leaving the coolant in the accumulator air free. After the engine is stopped, contraction of the cooling liquid in the radiator causes a pressure differential with the outside atmosphere, forcing liquid from the accumulator back into the radiator. Because the opening of the overflow tube is at all times kept below the surface of the fluid in the accumulator, no gaseous matter is readmitted into the otherwise hermetically sealed system. After several cycles of operation, substantially all air is eliminated from the cooling system, leaving only noncompressible liquid coolant. The system therefore becomes pressurized very quickly after the engine is started, thus preventing boiling of the coolant at normal engine temperatures.