PURPOSE: To prevent pulsation without possibility generating the spoilage or leakage of a liquid due to the stay thereof and the cracking of a connection part, by assembling an accumulator in the pipeline for supplying a liquid to a membrane separation apparatus from a pump so as to provide an interval between the inner peripheral surface of the pipeline and the accumulator.

CONSTITUTION: To a pipeline 1 connected to a pump at the upstream side 1a thereof and to a membrane separation apparatus at the downstream side 1b thereof, a bladder attachment plate 3, a bladder receiving cylinder 4 having a petal shaped inner surface and a bladder support plate 5 are connected on the way thereof in series and an inert gas injection part 2' is received in the bladder receiving cylinder 4 so as to be directed to the upstream side 1a of the pipeline 1. The bladder attachment plate 3 and the bladder support plate 5 are provided with radial arms 6, 6 reaching the outer peripheral parts thereof from the central parts thereof and liquid passing ports 6' are formed between the arms 6, 6. Inert gas is sealed in a bladder 2 corresponding to the emitting pressure of a pump 2. When pressure becomes high by the pulsation of a liquid, the bladder 2 is contracted to absorb the rising in pressure and expanded to be returned to the original state when pressure becomes low to pressurize the liquid which is, in turn, supplied to the membrane separation apparatus without generating pulsation.