Back pressure regulator valve

A spraying system comprising:

• a fluid supply;
• a fluid supply line;
• a spray nozzle in communication with the fluid supply line;
• a pump arranged in the fluid supply line between the fluid supply and the spray nozzle;
• a back pressure regulator valve communicating with a fluid return line;
• the back pressure regulator valve being arranged and configured to control pressure in the spray nozzle and in the fluid supply line between the spray nozzle and the pump;
• the back pressure regulator valve comprising:
• a valve body having a fluid inlet in communication with a fluid inlet passage in the valve body and a fluid outlet in communication with a fluid outlet passage in the valve body;
• wherein an array of grooves that are circular and concentric are provided in an end wall of the valve body that are separated by an array of concentric vanes, with each of the grooves having a continuously variable depth as the respective groove extends circumferentially;
• wherein the array of grooves includes a plurality of first grooves, a depth of each of the first grooves reaches a maximum depth where the respective first groove communicates with the fluid outlet passage and reaches a minimum depth adjacent the fluid inlet passage where the respective first groove does not communicate with the fluid inlet passage;
• wherein the array of grooves includes a plurality of second grooves, a depth of each second groove reaches a maximum depth where the respective second groove communicates with the fluid inlet passage and reaches a minimum depth adjacent the fluid outlet passage where the respective second groove does not communicate with the fluid outlet passage;
• wherein the array of grooves alternates between first grooves and second grooves in a radial direction of the array of grooves;
• wherein the fluid inlet passage and the fluid outlet passage each extend in the radial direction relative to the array of grooves;
• and
• a flexible diaphragm arranged to cover the array of grooves, the flexible diaphragm having a rest position where the flexible diaphragm rests on the array of vanes separating the array of grooves and the diaphragm being movable away from upper edges of the array of vanes in response to the presence of fluid in the one or more of the grooves to allow for fluid flow between adjacent grooves over the respective vane separating the adjacent grooves.