3.3 Batch and continuous lubricating systems For small or medium units without a circulatory lubricating system, the oil is often treated on the batch system As large a quantity of oil as possible is drained from the engine at intervals and run into a heating tank, the system being replenished with clean oil at the same time The heated oil is run through the purifier and pumped back to the main oil tank3.3 Batch and continuous lubricating systems • For small or medium units without a circulatory lubricating system, the oil is often treated on the batch system. • As large a quantity of oil as possible is drained from the engine at intervals and run into a heating tank, the system being replenished with clean oil at the same time. • The heated oil is run through the purifier and pumped back to the main oil tank