Crankcase Explosions: Development of New Protective Devices

Abstract

Tests of a crankcase explosion relief-valve 6 inches in diameter, provided with various wire-gauze flame traps showed such flame traps to be ineffective when ***severe explosions were made with mixtures of town gas and air. It was discovered that coating the wire gauze with lubricating oil greatly increased the effectiveness. of the flame trap. An internal, oil-wetted flame trap of less ***than half the original size was fully effective with the most severe explosion that could be produced. An oil-wetted flame trap, covering an aperture in a dividing partition of a cylindrical explosion vessel fully charged with gas-air mixture, was found to limit combustion to the chamber in which the mixture was ignited, and to limit the maximum pressure to one quarter of the value reached without the partition flame trap. Internal oil-wetted relief-valve flame traps and partition flame traps were then successfully tested on a ***three-cylinder engine of 9 inches bore. From the results obtained, the requirements of a large engine are estimated and it is concluded that the use of the two new devices would provide adequate protection at acceptable cost.