A canister is provided with a plurality of adsorbent chambers filled with adsorbent, and the adsorbent chambers are connected together so as to form a U-turn-shaped passage. The canister has a communication chamber through which both end portions of adjacent two adsorbent chambers communicate with each other; a middle chamber formed at the end portion of one of the adjacent two adsorbent chambers, which is positioned at a downstream side of the communication chamber, and connected to the communication chamber through a communication hole; a baffle plate set in the middle chamber with the baffle plate facing to the communication hole so that an incoming air flow from the communication hole strikes against the baffle plate and diffuses in the middle chamber; and a tubular portion protruding in the communication chamber from an opening edge of the communication hole along a longitudinal direction of the one adsorbent chamber.
1. A canister in which a plurality of adsorbent chambers filled with an adsorbent are connected in order, so as to form a U-turn-shaped flow passage and a charge port and a purge port are provided at one end of the flow passage and an air port is provided at the other end of the flow passage, the canister comprising:
a communication chamber through which both end portions of adjacent two adsorbent chambers communicate with each other, the communication chamber being formed by a part of a canister casing;
a middle chamber that is formed at the end portion of one of the adjacent two adsorbent chambers which is positioned at a downstream side, in a direction of an air flow from the air port to the purge port, of the communication chamber, the middle chamber being defined between the adsorbent of the one adsorbent chamber and the communication chamber and being connected to the communication chamber through a communication hole whose opening area is smaller than a cross-sectional area of the flow passage of the middle chamber;
a baffle plate that is set in the middle chamber with the baffle plate facing to the communication hole so that an incoming air flow from the communication hole strikes against the baffle plate and diffuses in the middle chamber; and
a tubular portion that protrudes in the communication chamber from an opening edge of the communication hole along a longitudinal direction of the one adsorbent chamber.
2. The canister as claimed in claim 1 , wherein:
the canister casing has a body in which the adjacent two adsorbent chambers are arranged and their both end portions open, and
the communication chamber is formed by fixing a communication chamber cover to the body of the canister casing.
3. The canister as claimed in claim 1 , wherein:
a top end portion of the tubular portion has an obliquely-cut shape so as to open toward the end portion of the other of the adjacent two adsorbent chambers which is positioned at an upstream side, in the direction of the air flow, of the communication chamber.
4. The canister as claimed in claim 1 , wherein:
a first adsorbent chamber having the charge port and the purge port, a third adsorbent chamber having the air port and a second adsorbent chamber positioned between the first and third adsorbent chambers are provided, and
the second adsorbent chamber and the third adsorbent chamber communicate with each other through the communication chamber.