PURPOSE: A spacer including a protrusion forming an outer wall of an O-ring is provided to prevent the separation of the O-ring from an O-ring groove by blocking the flow of condensing water. CONSTITUTION: A spacer(100) comprises a protrusion(142) preventing an O-ring from being separated from an O-ring groove(144) by the fluid pressure of condensing water inserted in to the O-ring groove. The O-ring is coupled to divide filtered processing water using membranes located on a separating space of the spacer, and the non-filtered condensing water.
