Check valve assembly

A non-return valve assembly for a high-pressure fuel injection system, comprising:

• a valve chamber defined in part by a first body and in part by a second body and defining a valve chamber wall, the first and second bodies defining respective planar mating faces, such that a part of the mating face of the first body abuts a part of the mating face of the second body to form a seal therebetween;
• an inlet passage formed in the first body and opening into the valve chamber at a valve seat defined by the first body;
• an outlet passage;
• and
• a valve ball received within the valve chamber and engageable with the valve seat so as to interrupt fluid flow from the outlet passage to the inlet passage through the valve chamber;
• wherein the valve chamber wall comprises a plurality of guide portions downstream of the valve seat to guide the valve ball in substantially linear movement within the valve chamber;
• wherein the plurality of guide portions are separated by a plurality of peripheral lobes downstream of the valve seat through which fluid flows past the valve ball when the valve ball is not engaged with the valve seat, the plurality of peripheral lobes being in fluid communication with the outlet passage when the valve ball is engaged with the valve seat to interrupt fluid flow from the outlet passage to the inlet passage.