Abstract: The present invention relates to an apparatus and method for maintaining a fluid mixing ratio. The apparatus according to various embodiments prevents a fluid flow imbalance between two proportionate fluid streams based on a pressure difference, and may be configured to alert the user and/or stop the fluid flow in the event of a fluid flow imbalance. The apparatus is formed such that two plunger components engage a shuttle piston, the shuttle piston configured to move one or more plunger components given a selectable fluid flow imbalance.

Abstract: The present invention is a fluid spraying assembly wherein a plurality of differently configured spray guns can be constructed therefrom. The assembly includes fluid spray nozzles and air caps having different configurations and techniques for attaching to a resulting spray gun body. The assembly further includes intermediate components for operably connecting differently configured fluid spray nozzles and air caps to a spray gun body assembly that is substantially common for all resulting spray guns.

Abstract: A fluid nozzle for an air assisted spray device is disclosed, wherein the fluid nozzle may have a nozzle tip therein which is more resistant to fluid abrasion than other portions of the fluid nozzle. In one embodiment, a plurality of nozzle tips are capable of being interchangeably used with a single main body of the fluid nozzle. Thus, replacement nozzle tips can be used when: (a) a nozzle tip effectiveness deteriorates due to wear, and (b) a fluid to be sprayed requires a nozzle tip with a different configuration. Further, in one embodiment, the fluid nozzle of the present invention provides an annular plenum between a recess wall of the main body, and an exterior portion of the nozzle tip. Such a plenum is used to enhance the volume and turbulence within an air chamber of the spray device prior to the air exiting for atomizing the fluid being sprayed. Thus, such enhanced turbulence provides a more uniform air velocity exiting the air chamber.