Air dryer for a brake system

A membrane air dryer for insertion into a reservoir or an inlet or outlet of the reservoir, the dryer comprising:

• a housing with an air inlet adjacent to a first end of the housing, an air outlet adjacent to a second end of the housing and a sweep air and liquid drain outlet adjacent the first end of the housing;
• a membrane separator having surfaces extending between first and second ends of the membrane;
• a first passage in the housing connected to the air inlet and air outlet at it respective ends and extending between the first and second ends of the membrane separator along the surfaces of the membrane separator;
• a second passage in the housing connected to the sweep air and liquid drain outlet and a sweep air inlet at respective ends and extending between the first and second ends of the membrane along a surface of the membrane separator;
• a valve connected to the sweep air and liquid drain outlet for controlling the draining of the liquid and sweep air flow and also controlling flow of the sweep air through the second passage, the valve being connected to the sweep air and liquid drain outlet at the first end of the housing, and
• a cover removably mounted to the housing at the first end and adjacent to the membrane separator to allow removal of the membrane separator from the housing at the first end, wherein the air inlet, the sweep air and liquid drain outlet and the valve are offset from a longitudinal axis of the membrane separator and the cover for servicing the membrane separator by removal of the cover without complete removal of the membrane air dryer from the reservoir.