Three-way valve

A three-way valve comprising:

• a valve main body having a first valve chamber, one end of which is provided with a first inlet port, a second valve chamber, one end of which is provided with a second inlet port, a path for communicating the other end of the first valve chamber with the other end of the second valve chamber, a first valve seat disposed on the other end of the first valve chamber, a second valve seat disposed on the other end of the second chamber, and an outlet port communicating with said path;
• a first main valve disposed within said first valve chamber and selectively movable between a first position in which the first main valve comes into contact with the first valve seat to seal the first valve chamber, a second position in which the first main valve is separated from the first valve seat by a first distance, and a third position in which the first main valve is separated from the first valve seat by a second distance greater than the first distance;
• a second main valve disposed within said second valve chamber and selectively movable between a fourth position in which the second main valve comes into contact with the second valve seat to seal the second valve chamber, a fifth position in which the second main valve is separated from the second valve seat by a third distance, and a sixth position in which the second main valve is separated from the second valve seat by a fourth distance greater than the third distance;
• and
• control means disposed within the valve main body for (a) moving the first main valve from the third position to the first position while simultaneously moving the second main valve from the fourth position to the fifth position when the pressure within the first valve chamber is greater than the pressure within the second valve chamber by a first value to thereby close the first valve chamber and establish communication between the second valve chamber and the outlet port, (b) moving the second main valve from the fifth position to the sixth position when the pressure within the first valve chamber is greater than the pressure within the second valve chamber by a second value greater than the first value to thereby separate the second main valve and the second valve seat greatly from each other, (c) moving the second main valve from the sixth position to the fourth position while simultaneously moving the first main valve from the first position to the second position when the pressure within the second valve chamber is greater than the pressure within the first valve chamber by a third value to thereby close the second valve chamber and establish communication between the first valve chamber and the outlet port;
• and (d) moving the first main valve from the second position to the third position when the pressure within the second valve chamber is greater than the pressure within the first valve chamber by a fourth value which is greater than the third value to thereby separate the first main valve and the first valve seat greatly from each other.