Erosion resistant check valve assembly

DETAILED DESCRIPTION As in the prior art, the invention utilizes a ball that seats in a longitudinal passage to prevent upward flow during a blowout.
A recess or side pocket receives the ball to remove it from the downward flow in the longitudinal passage during normal drilling.
To prevent the ball from being drawn partially into the longitudinal passage during drilling, and to solve the resulting problems of the prior art inside blowout preventors, a replaceable insert is used to form the major portions of the longitudinal passage and the side pocket for the ball.
The equalizing passage extending from the side pocket is formed between the body of the assembly and the recess.
As shown in the drawing, the throat of the longitudinal passage, where the seat is located, is offset from center to provide for the side pocket.
The equalizing passage is preferably an annular space.
The ball is sufficiently smaller than the side pocket to reduce the velocity of the fluid flowing pass the ball and through the equalizer passage.
Lower fluid velocities reduce erosion caused by the fluid and the solid particles that are often present in drilling mud.
Further, the insert may be easily replaced at the conclusion of its natural life span, without the necessity and cost of replacing the entire assembly.
Additional objects, features and advantages will become apparent in view of the following description.