Abstract: A positive displacement pump includes a housing surrounding a drive chamber and a diaphragm compartment. A drive element is inside the drive chamber. A diaphragm is inside the diaphragm compartment and divides the diaphragm compartment into a fluid chamber and a cavity. A shaft connects the drive element and the diaphragm. A breather valve is fluidically connected to the cavity and is configured to allow air to exit the cavity. The cavity is fluidically disconnected from the drive chamber.

Abstract: A back pressure regulator (“BPR”) includes a pressure housing that at least partially defines a flow chamber that the liquid flows through and the BPR has an adjustable restriction that varies with the flow rate to maintain an upstream liquid pressure. The pressure housing is contoured to distribute the liquid flow to provide radial flow into the adjustable restriction from circumferentially about the adjustable restriction. The pressure housing includes ramped and curved side passages that guide the flow and ridges that divide the flow and prevent internal collisions between the flow. A flow deflector extends into the chamber outlet to prevent the radial flows through the annular restriction from colliding. The flow deflector redirects the flows to smoothly recombine in the chamber outlet.

Abstract: A positive displacement pump includes a housing surrounding a drive chamber and a diaphragm compartment. A drive element is inside the drive chamber. A diaphragm is inside the diaphragm compartment and divides the diaphragm compartment into a fluid chamber and a cavity. A shaft connects the drive element and the diaphragm. A breather valve is fluidically connected to the cavity and is configured to allow air to exit the cavity. The cavity is fluidically disconnected from the drive chamber.

Abstract: A positive displacement pump includes a housing surrounding a drive chamber and a diaphragm compartment. A drive element is inside the drive chamber. A diaphragm is inside the diaphragm compartment and divides the diaphragm compartment into a fluid chamber and a cavity. A shaft connects the drive element and the diaphragm. A breather valve is fluidically connected to the cavity and is configured to allow air to exit the cavity. The cavity is fluidically disconnected from the drive chamber.

Abstract: A positive displacement pump includes a housing surrounding a drive chamber and a diaphragm compartment. A drive element is inside the drive chamber. A diaphragm is inside the diaphragm compartment and divides the diaphragm compartment into a fluid chamber and a cavity. A shaft connects the drive element and the diaphragm. A breather valve is fluidically connected to the cavity and is configured to allow air to exit the cavity. The cavity is fluidically disconnected from the drive chamber.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an electromagnetic alternator, a housing and an impeller. The electromagnetic alternator has a shaft. The electromagnetic alternator is disposed within the housing. The housing has an air aperture. The impeller is mounted to the shaft within the housing so as to be aligned with the air aperture. The impeller includes blades having curved leading and trailing edges. In one embodiment, each blade has a curvature so as to be perpendicular to the air aperture across an entire arc over which each impeller blade has a line of sight of the air aperture.

Abstract: A check valve assembly includes a housing extending axially along a center axis of the check valve assembly from a first end to a second end. The housing can include an opening disposed at the first end and an outlet disposed at the second end. A seat is disposed in the opening and connected to the tubular housing. The seat includes an inlet extending axially through the seat. A ball is disposed inside the tubular housing and disposed axially between the seat and the outlet. The ball is larger in diameter than the inlet. A ball guide is disposed inside the tubular housing and is disposed axially between the ball and the outlet. A spring is disposed inside the tubular housing and disposed axially between the ball guide and the outlet. The spring is compressed between the ball guide and the outlet.

Abstract: A fluid cover for a displacement pump includes an inlet and an outlet oriented to provide desired flow characteristics to fluid entering a fluid chamber defined between the fluid cover and a diaphragm. The inlet is positioned to provide fluid to the fluid chamber at an oblique angle relative to the fluid cover. The oblique angle prevents the fluid from impinging on the fluid cover and the diaphragm, thereby maintaining a fluid velocity within the fluid chamber. The fluid velocity and rotational movement of the fluid facilitates flushing of the fluid chamber, as areas of low velocity or no velocity are eliminated from the fluid chamber, thereby preventing residuals from settling within the fluid chamber. The outlet is also positioned at an oblique angle to the fluid cover to maintain the rotational movement of the fluid flow.

Abstract: A check valve assembly includes a housing extending axially along a center axis of the check valve assembly from a first end to a second end. The housing can include an opening disposed at the first end and an outlet disposed at the second end. A seat is disposed in the opening and connected to the tubular housing. The seat includes an inlet extending axially through the seat. A ball is disposed inside the tubular housing and disposed axially between the seat and the outlet. The ball is larger in diameter than the inlet. A ball guide is disposed inside the tubular housing and is disposed axially between the ball and the outlet. A spring is disposed inside the tubular housing and disposed axially between the ball guide and the outlet. The spring is compressed between the ball guide and the outlet.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an electromagnetic alternator, a housing and an impeller. The electromagnetic alternator has a shaft. The electromagnetic alternator is disposed within the housing. The housing has an air aperture. The impeller is mounted to the shaft within the housing so as to be aligned with the air aperture. The impeller includes blades having curved leading and trailing edges. In one embodiment, each blade has a curvature so as to be perpendicular to the air aperture across an entire arc over which each impeller blade has a line of sight of the air aperture.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an electromagnetic alternator, a housing and an impeller. The electromagnetic alternator has a shaft. The electromagnetic alternator is disposed within the housing. The housing has an air aperture. The impeller is mounted to the shaft within the housing so as to be aligned with the air aperture. The impeller includes blades having curved leading and trailing edges. In one embodiment, each blade has a curvature so as to be perpendicular to the air aperture across an entire arc over which each impeller blade has a line of sight of the air aperture.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an alternator housing, a stator, a rotor, a shaft, a first bearing and a sheath. The stator is inserted into the alternator housing and has an inner diameter and an outer diameter. The rotor is disposed within the inner diameter of the stator. The shaft extends from the rotor and is rotatably supported by a first bearing. The sheath surrounds the outer diameter, supports the stator with respect to the alternator housing, and supports the bearing.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an alternator housing, a stator, a rotor, a shaft, a first bearing and a sheath. The stator is inserted into the alternator housing and has an inner diameter and an outer diameter. The rotor is disposed within the inner diameter of the stator. The shaft extends from the rotor and is rotatably supported by a first bearing. The sheath surrounds the outer diameter, supports the stator with respect to the alternator housing, and supports the bearing.

Abstract: An alternator, such as for use in an electrostatic spray gun, comprises an electromagnetic alternator, a housing and an impeller. The electromagnetic alternator has a shaft. The electromagnetic alternator is disposed within the housing. The housing has an air aperture. The impeller is mounted to the shaft within the housing so as to be aligned with the air aperture. The impeller includes blades having curved leading and trailing edges.