Check valve

A check valve, comprising:

• a housing having a first opening in a first end thereof and a second opening in a second end thereof, the first opening having one or more slots extending radially therefrom and extending axially from the first end into an interior of the housing, the one or more slots in communication with a circumferential groove formed in the interior of the housing, the housing comprising first and second stops that extend into the circumferential groove in a direction toward the first opening;
• a seal biased in sealing contact with a seat in the interior of the housing by a biasing force exerted on a cage that is connected to the seal;
• a nipple configured to be selectively installed in the first opening of the housing;
• and
• a spring that exerts the biasing force on the cage, wherein the cage comprises a first portion that is located within a bore of the spring and a second portion having a first surface that abuts an end of the spring and a second surface opposite the first surface that the first end of the nipple bears against when the nipple is installed in the first opening of the housing, wherein an opposite end of the spring abuts the seat so that the spring is between the seat and the first surface of the second portion of the cage and such that the spring is between the first end of the nipple and the seat when the nipple is installed in the first opening of the housing;
• wherein the nipple has one or more pins extending from an exterior surface thereof so that when the nipple is installed in the first opening of the housing, the nipple passes through the first opening and the one or more pins are received within the circumferential groove respectively through the one or more slots;
• wherein when the nipple is installed in the first opening of the housing, a first end of the nipple bears against the cage so as to hold the seal out of sealing contact with the seat, thereby fluidly coupling the second opening to an opening in a second end of the nipple that is located exteriorly of the housing;
• and
• wherein the first stop is located in a first nipple-locking position at a first angular distance in a clockwise direction along a circumference of the circumferential groove from one of the one or more slots and the second stop is located in a second nipple-locking position at a second angular distance different than the first angular distance in a counterclockwise direction along the circumference of the circumferential groove from the one of the one or more slots.

A check valve, comprising:

• a housing;
• a nipple having a first portion that is selectively positionable within an opening in the housing, wherein a second portion of the nipple extends from the housing when the first portion of the nipple is selectively positioned within the opening in the housing;
• and
• a seal movably disposed within the housing;
• a cage connected to the seal;
• and
• a spring surrounding a first portion of the cage and located between a seat and a second portion of the cage;
• wherein the spring biases the seal against the seat when the first portion of the nipple is removed from the housing;
• wherein the first portion of the nipple bears against the second portion of the cage when the first portion of the nipple is selectively positioned within the opening in the housing so that the spring is between the first portion of the nipple and the seat;
• wherein the check valve is configured to allow fluid flow through the check valve in either a first direction or a second direction when the first portion of the nipple is selectively positioned within the opening in the housing;
• wherein the check valve is configured to prevent fluid flow through the check valve in the first direction when the first portion of the nipple is removed from the housing;
• wherein the housing comprises one or more slots in the opening in the housing, the one or more slots extending axially from a first end of the housing into an interior of the housing to a circumferential groove formed on an interior wall of the housing, the circumferential groove having two stops, each stop extending in a direction toward the opening within the circumferential groove, each stop locking the nipple in the housing, the first stop positioned a first angular clockwise distance within the circumferential groove from the one or more slots, the second stop positioned a second angular counterclockwise distance within the circumferential groove from the one or more slots;
• and
• wherein one or more pins that protrude from an exterior of the first portion of the nipple are configured to move circumferentially within the groove in response to the nipple being rotated.