A bonnetless, self-relieving valve for use between a source of pressurized fluid and a pressure gauge comprising:
- a valve body;
- a flow passageway formed in said valve body and including a first segment of relatively small diameter adapted for connection to a pressure gauge, and a second segment having a diameter which is relatively large in comparison to the diameter of said first segment adapted for connection to a pressurized fluid;
- a cylindrical bore of substantially larger diameter than said first segment of said flow passageway extending through said valve body and transversely intersecting said flow passageway, with said first and second segments of said flow passageway disposed on opposite sides of said bore from each other;
- a cylindrical valve stem journaled in said cylindrical bore and having a transverse cavity therein radially aligned with, and extending normal to, the axis of rotation of said valve stem in said bore, said cavity having a substantially larger transverse dimension than said first segment of said flow passageway and said valve stem having an intermediate peripheral portion of smaller diameter than said cylindrical bore and located opposite said first and second segments of said flow passageway to provide fluid communication between said first and second segments when said valve is open, said intermediate peripheral portion being continuously open to, and in communication with, said second segment of said flow passageway to provide an open flow passageway for pressure equalization across said valve stem between said first and second segments of said flow passageway when fluid pressure in said first segment exceeds the fluid pressure in said second segment of said flow passageway;
- a pair of axially spaced seals mutually engaging said valve stem and said bore for providing a fluid-tight communication between said cylindrical bore and the segments of said flow passageway via said intermediate peripheral portion of said stem;
- a valve seat disposed in said body along the line of intersection of said first segment of said flow passageway and said bore;
- a spherical valve member having an uninterrupted spherical external surface, one-half of which is of substantially larger area than the area of said valve seat means, said spherical valve member being adapted for rotated motion about an infinite number of axes of rotation relative to said valve stem and valve seat for engaging said valve seat with a portion of its peripheral external surface to close said first segment of said flow passage and, alternately, rollingly disengaging from said valve seat means to open said first segment of said flow passage when said valve stem is rotated in said bore;
- biasing means disposed in said cavity and operatively engaging said valve stem and said valve member by contact with said valve member over a portion of the spherical external surface of said valve member which is substantially larger in area than the area of said valve seat, and substantially larger in area than the cross-sectional area of said first segment of said flow passage, said biasing means being resiliently yieldable in a direction away from said valve seat along a line in alignment with the axis of the first segment of said flow passageway to relieve excessive pressure in said first segment;
- and
- operating means engageable with said valve stem for pivoting said valve stem and said valve member relative to said valve seat and said valve body about the axis of said cylindrical bore into a position closing said flow passageway and, alternately, into a position opening said flow passageway.