3.3 Batch and continuous lubricating systems The outlet for purified oil is connected to the top of the sump-tank by means of the return pipe. 蘸an The water and sludge outlet is connected to the waste by a pipe 73.3 Batch and continuous lubricating systems • The outlet for purified oil is connected to the top of the sump-tank by means of the return pipe. • The water and sludge outlet is connected to the waste by a pipe