Four-port valve

A four-port valve which has four ports and in which directions of the flow of fluid passing through the ports provided on the two opposed positions are fixed and the other two ports provided between said ports are selectively communicated with either of said two ports in a casing to change over the fluid passing through the ports, the four-port valve characterized in that:

• the inside of the casing is divided into four chambers by a substantially-X-shaped partition wall;
• the opposed two of the four chambers are determined as fixing chambers communicating with the ports respectively connected with two types of passages in which directions of the flow of fluid are fixed while the remaining two opposed chambers are determined as change-over chambers communicating with the ports respectively connected with two types of passages in which directions of the flow of fluid are alternately changed over;
• valve openings for communicating two chambers adjacent to the substantially-X-shaped partition wall with each other are provided;
• a valve plate for closing the valve openings and a drive shaft for supporting and oscillating the valve plate are provided to one among the four chambers while a valve plate for closing the valve openings is provided to the opposed chamber so as to be connected with the valve plate supported by the drive shaft by a semi-circular or circular connecting ring piercing through the valve openings;
• and the valve plate oscillating by rotation of the drive shaft is interlocked with the other valve plate to alternately communicate the two fixing chambers with the different change-over chambers.