Adjustable valve assembly

Claim 1

A valve comprising a housing having at an upstream end a tubular inlet and at a downstream end a tubular outlet coaxial with said inlet to provide a straight-line throughflow for fluid, a valve seat carried by said housing between said inlet and outlet thereof and having an annular flat seating surface of substantial area directed away from said tubular inlet of said housing, a valve member extending across said valve seat in the path of fluid flow from said inlet to said outlet and having a flat closure surface engaging said seating surface over said substantial area thereof when said valve member is in a closed position preventing flow of fluid from said inlet to said outlet, and spring means coacting with said valve member for continuously urging the latter into engagement with said seat so that a check valve operation limiting the flow only from said inlet to said outlet is achieved, said valve seat and valve member having said flat surfaces thereof respectively located in parallel planes normal to a common axis inclined to the common axis of said inlet and outlet and forming an acute angle with the latter common axis, a shut-off means coacting with said valve member for maintaining the latter in engagement with said seat so that the function of a shut-off valve is also achieved, adjusting means coacting with said shut-off means for adjusting the distance between the latter and said valve member to provide for said valve member an adjusted degree of opening movement away from said valve seat, to achieve also the operation of a throttle valve, said valve member having a first elongated stem extending along the common axis of said valve member and valve seat and terminating in an end surface directed away from said inlet and a second elongated stem coaxial with said first stem and extending toward said inlet, said shut-off means including an elongated shut-off member engaging said end surface of said first valve stem to maintain said valve member in its closed position, and said adjusting means including an elongated threaded shank portion of said shut-off member and a nut engaging said threaded shank portion, so that said shank portion can be turned to be situated at a selected distance from said end surface of said valve stem, said shut-off member having an exterior portion provided with graduations distributed axially along said latter exterior portion, and an index carried by said housing and coactIng with said graduations for indicating the position of said shut-off member along the common axis of said valve member and valve seat to indicate either the shut-off position or the degree to which said valve member can be displaced away from said valve seat to achieve the action of a throttle valve, first and second spiders respectively carried by said housing and said valve seat, and first and second tubular guides respectively carried by said spiders and surrounding and engaging said first and second stems, respectively, for guiding said valve member for movement precisely along said common axis of said valve member and valve seat.