Force balanced three-way solenoid valve

A pressure balanced three-way valve assembly, comprising

• a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• a movable valve member mounted for reciprocal movement within said valve chamber between first and second positions, said movable valve member containing a cavity opening into at least one end of said movable valve member;
• a stop means for defining one of said first and second positions of said movable valve member, said stop means including a floating pin arranged to be telescopingly received within said cavity of said movable valve member;
• a first valve seat associated with said valve housing and said movable valve member, said first valve seat being positioned to be closed when said movable valve member is in said first position to seal said third valve passage from the said first and second valve passages and allow fluid communication between said first and second valve passages through said valve chamber;
• a second valve seat associated with said movable valve member, said second valve seat being positioned to be closed when said movable valve member is in said second position to seal said second valve passage from said first and third valve passages and allow fluid communication between said first and third valve passages;
• and
• force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and in said second position;
• and
• wherein said stop means further includes an adjustable retraction stop located within said valve housing for engaging one end of said floating pin to determine said second position when said movable valve member is retracted from said first position.

A pressure balanced three-way valve assembly, comprising

• a. a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• b. a movable valve member mounted for reciprocal movement within said valve chamber between
• i. a first position in which said third valve passage is isolated from said first and second valve passages and said first and second valve passages are in fluid communication, and
• ii. a second position in which said second valve passage is isolated from said first and third valve passages and said first and third passages are in fluid communication;
• c. a solenoid operator means for controlling the valve assembly by displacing said movable valve member between said first and second positions, said solenoid operator means being mounted on one side of said valve housing;
• and
• d. stop means mounted on said valve housing opposite said solenoid operator means for permitting adjustment in one of said positions of said movable valve means including a floating pin telescopingly received in one end of said movable valve member and an adjustable retraction stop mounted to engage one end of said floating pin when said movable valve member is moved to one of said positions, said retraction stop being selectively adjustable to vary said corresponding position of said movable valve member.

A pressure balanced three-way valve assembly, comprising

• a. a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• b. a movable valve member mounted for reciprocal movement within said valve chamber between
• i. a first position in which said third valve passage is isolated from said first and second valve passages and said first and second valve passages are in fluid communication, and
• ii. a second position in which said second valve passage is isolated from said first and third valve passages and said first and third passages are in fluid communication,
• said movable valve member containing a cavity opening into one end of said movable valve member;
• c. a floating pin telescopingly received within said cavity of said movable valve member;
• d. a first valve seat located within said valve chamber and positioned to be closed when said movable valve member is in said first position to isolate said third valve passage from said first and second valve passages and allow fluid communication between said first and second valve passages;
• e. a second valve seat located within said cavity of said movable valve member, said second valve seat being positioned to be closed by said floating pin when said movable valve member is in said second position to seal said second passage from said first and third valve passages and allow fluid communication between said first and third valve passages;
• f. force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and in said second position;
• g. biasing means for causing said floating pin to follow said movable valve member to keep said second valve seat closed as said movable valve member is advanced toward said first position from said second position;
• and
• h. advancement stop means for preventing said floating pin from following said movable valve member all of the way to said first position to insure thereby that said second valve seat is opened before said movable valve member reaches said first position.

A pressure balanced three-way valve assembly, comprising

• a. a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• b. a movable valve member mounted for reciprocal movement within said valve chamber between
• i. a first position in which said third valve passage is isolated from said first and second valve passages and said first and second valve passages are in fluid communication, and
• ii. a second position in which said second valve passage is isolated from said first and third valve passages and said first and third passages are in fluid communication,
• said movable valve member containing a cavity opening into one end of said movable valve member;
• c. a floating pin telescopingly received within said cavity of said movable valve member;
• d. a first valve seat located within said valve chamber and positioned to be closed when said movable valve member is in said first position to isolate said third valve passage from said first and second valve passages and allow fluid communication between said first and second valve passages;
• e. a second valve seat located within said cavity of said movable valve member, said second valve seat being positioned to be closed by said floating pin when said movable valve member is in said second position to seal said second passage from said first and third valve passages and allow fluid communication between said first and third valve passages;
• f. force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and said second position,
• g. stop means for engaging said floating pin upon return of said movable valve member to define said second position;
• and
• h. biasing means for biasing said floating pin toward said movable valve member to cushion the impact of said floating pin with said stop means.

A pressure balanced three-way valve assembly, comprising

• a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• a movable valve member mounted for reciprocal movement within said valve chamber between first and second positions, said movable valve member forming a closely fitting, fluid seal forming first gap with said valve housing, said movable valve member containing a cavity opening into at least one end of said movable valve member;
• a stop means for defining one of said first and second positions of said movable valve member, said stop means including a floating pin arranged to be telescopingly received within said cavity, said floating pin forming a closely fitting, fluid seal forming second gap with said movable valve member;
• a first valve seat associated with said valve housing and said movable valve member, said first valve seat being positioned to be closed when said movable valve member is in said first position to seal said third valve passage from the said first and second valve passages and allow fluid communication between said first and second valve passages through said valve chamber;
• a second valve seat associated with said movable valve member, said second valve seat being positioned to be closed when said movable valve member is in said second position to seal said second valve passage from said first and third valve passages and allow fluid communication between said first and third valve passages;
• wherein said movable valve member includes fluid leakage reduction means for reducing the amount of fluid allowed to leak through said first and second gaps, said fluid leakage reduction means including a small passage contained in said movable valve means for interconnecting said first and second gaps.

A pressure balanced three-way valve assembly, comprising:

• a valve housing containing a valve chamber, and a supply passage, an outlet passage and a drain passage, each communicating with said valve chamber;
• a movable valve member mounted for reciprocal movement within said valve chamber between first and second positions, said movable valve member containing a cavity opening into at least one end of said movable valve member;
• solenoid means for advancing said movable valve member toward its second position when energized and for allowing said movable valve member to retract to its first position when de-energized;
• a stop means for defining one of said first and second positions of said movable valve member, said stop means including a floating pin arranged to be telescopingly received within said cavity of said movable valve member;
• a first valve seat associated with said movable valve member, said first valve seat being positioned to be closed when said movable valve member is in said first position to seal said supply passage from the said outlet passage and said drain passage and allow fluid communication between said outlet passage and drain passage through said valve chamber;
• a second valve seat associated with said movable valve member, said second valve seat being positioned to be closed when said movable valve member is in said second position to seal said drain passage from said outlet passage and said supply passage and allow fluid communication between said outlet passage and said supply passage;
• and
• force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and in said second position.

A pressure balanced three-way valve assembly, comprising:

• a valve housing containing a valve chamber, and a supply passage, an outlet passage and a drain passage, each communicating with said valve chamber;
• a movable valve member mounted for reciprocal movement within said valve chamber between first and second positions, said movable valve member including a first end and a second end spaced axially from said first end, said movable valve member containing a cavity opening into at least one said first and said second ends of said movable valve member;
• a stop means for defining one of said first and second positions of said movable valve member, said stop means including a floating pin arranged to be telescopingly received within said cavity of said movable valve member;
• a first valve seat associated with said movable valve member, said first valve seat being positioned to be closed when said movable valve member is in said first position to seal said supply passage from the said outlet passage and said drain passage and allow fluid communication between said outlet passage and drain passage through said valve chamber;
• a second valve seat associated with said movable valve member, said second valve seat being positioned to be closed when said movable valve member is in said second position to seal said drain passage from said outlet passage and said supply passage and allow fluid communication between said outlet passage and said supply passage;
• and
• force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and in said second position, wherein fluid forces tending to move said movable valve member in one direction resulting from supply fluid pressure acting on said movable valve member between said movable valve member and said floating pin are substantially balanced by fluid forces tending to move the valve member in an opposite direction resulting from supply fluid pressure acting on said movable valve member between said movable valve member and said valve housing intermediate said first and said second ends of said movable valve member when said movable valve member is in said second position.

A pressure balanced three-way valve assembly, comprising:

• a valve housing containing a valve chamber, and a supply passage, an outlet passage and a drain passage, each communicating with said valve chamber;
• a movable valve member mounted for reciprocal movement within said valve chamber between first and second positions, said movable valve member containing a cavity opening into at least one end of said movable valve member;
• a recess formed in said valve housing radially between said movable valve member and said valve housing;
• a stop means for defining one of said first and second positions of said movable valve member, said stop means including a floating pin arranged to be telescopingly received within said cavity of said movable valve member;
• a first valve seat associated with said movable valve member, said first valve seat being positioned to be closed when said movable valve member is in said first position to seal said supply passage from the said outlet passage and said drain passage and allow fluid communication between said outlet passage and drain passage through said valve chamber;
• a second valve seat associated with said movable valve member, said second valve seat being positioned to be closed when said movable valve member is in said second position to seal said drain passage from said outlet passage and said supply passage and allow fluid communication between said outlet passage and said supply passage;
• force balancing means for balancing fluid pressure forces tending to move said movable valve member in opposite directions resulting from supply fluid pressure acting on said movable valve member causing said movable valve member to be fluid force balanced while both in said first position and in said second position, wherein fluid forces tending to move said movable valve member in one direction resulting from supply fluid pressure acting on said movable valve member between said movable valve member and said floating pin are substantially balanced by fluid forces tending to move said movable valve member in an opposite direction resulting from supply fluid pressure acting on said movable valve member in said recess between said movable valve member and said valve housing when said movable valve member is in said second position.

A pressure balanced three-way valve assembly, comprising

• a. a valve housing containing a valve chamber and first, second and third valve passages communicating with said valve chamber;
• b. a movable valve member mounted for reciprocal movement within said valve chamber between
• i. a first position in which said third valve passage is isolated from said first and second valve passages and said first and second valve passages are in fluid communication, and
• ii. a second position in which said second valve passage is isolated from said first and third valve passages and said first and third passages are in fluid communication,
• said movable valve member containing a cavity opening into one end of said movable valve member;
• c. a floating pin telescopingly received within said cavity of said movable valve member;
• d. a first valve seat located within said valve chamber and positioned to be closed when said movable valve member is in said first position to isolate said third valve passage from said first and second valve passages and allow fluid communication between said first and second valve passages;
• e. a second valve seat located within said cavity of said movable valve member, said second valve seat being positioned to be closed by said floating pin when said movable valve member is in said second position to seal said second passage from said first and third valve passages and allow fluid communication between said first and third valve passages;
• f. biasing means for causing said floating pin to follow said movable valve member to keep said second valve seat closed as said movable valve member is advanced toward said first position from said second position;
• and
• g. advancement stop means for preventing said floating pin from following said movable valve member all of the way to said first position to insure thereby that said second valve seat is opened before said movable valve member reaches said first position, wherein said floating pin includes a radial flange and said advancement stop means includes a shim positioned to engage said radial flange during advancement of said movable valve member, said shim being adapted for removal and replacement with another shim having a different axial length to vary the point during advancement of said movable valve member that further advancement of said floating pin is arrested to open said second valve seat.