A pump, comprising: an outlet port; an outlet section in fluid communication with the outlet port; an inlet port; a ball cage, comprising: a first ball disposed therewithin; spaced apart opposing first and second ends (30, 32); a first opening at the first end of the ball cage, the first opening in fluid communication with the inlet port; and a second opening at the second end of the ball cage; wherein, the ball cage is configured for uninhibited displacement of the first ball within the ball cage; and a first seat at the first end of the ball cage; and a substantially hollow middle section extending between the outlet section and the ball cage, the middle section in fluid communications with the outlet section and with the second opening; wherein at least one passage defined at least in part by the first ball, by a wall of the ball cage and by one or more smaller openings defined by unblocked portions of the second opening formed at the second end of the ball cage extends between the first opening at the first end of the ball cage and the second opening at the second end of the ball cage so that material entering the pump through the inlet port flows into the ball cage through the first opening and along the at least one passage to exit the ball cage through the one or more smaller openings at the second end; and wherein material flows from the inlet port through the first opening into the at least one passage and through at least a portion of the second opening into the middle section; characterized in that a cross-sectional area of the at least one passage decreases with increasing distance from the first opening, so that a velocity of material flowing through the at least one passage increases with increasing distance from the first opening to the one or more small openings at the second end of the ball cage. an outlet port; an outlet section in fluid communication with the outlet port; an inlet port; a ball cage, comprising: a first ball disposed therewithin; spaced apart opposing first and second ends (30, 32); a first opening at the first end of the ball cage, the first opening in fluid communication with the inlet port; and a second opening at the second end of the ball cage; wherein, the ball cage is configured for uninhibited displacement of the first ball within the ball cage; and a first seat at the first end of the ball cage; and a substantially hollow middle section extending between the outlet section and the ball cage, the middle section in fluid communications with the outlet section and with the second opening; wherein at least one passage defined at least in part by the first ball, by a wall of the ball cage and by one or more smaller openings defined by unblocked portions of the second opening formed at the second end of the ball cage extends between the first opening at the first end of the ball cage and the second opening at the second end of the ball cage so that material entering the pump through the inlet port flows into the ball cage through the first opening and along the at least one passage to exit the ball cage through the one or more smaller openings at the second end; and a first ball disposed therewithin; spaced apart opposing first and second ends (30, 32); a first opening at the first end of the ball cage, the first opening in fluid communication with the inlet port; and a second opening at the second end of the ball cage; wherein, the ball cage is configured for uninhibited displacement of the first ball within the ball cage; and a first seat at the first end of the ball cage; and a substantially hollow middle section extending between the outlet section and the ball cage, the middle section in fluid communications with the outlet section and with the second opening; wherein at least one passage defined at least in part by the first ball, by a wall of the ball cage and by one or more smaller openings defined by unblocked portions of the second opening formed at the second end of the ball cage extends between the first opening at the first end of the ball cage and the second opening at the second end of the ball cage so that material entering the pump through the inlet port flows into the ball cage through the first opening and along the at least one passage to exit the ball cage through the one or more smaller openings at the second end; and wherein material flows from the inlet port through the first opening into the at least one passage and through at least a portion of the second opening into the middle section; characterized in that a cross-sectional area of the at least one passage decreases with increasing distance from the first opening, so that a velocity of material flowing through the at least one passage increases with increasing distance from the first opening to the one or more small openings at the second end of the ball cage.