Standex International Corporation

Robert E Harvey, Iii

Robert R Kimberlin

William M Larson

Jie Jiang

William Rawnsley, Jr

A fluid pump includes a pump head having an inlet for receiving fluid at a first pressure and an outlet for outputting fluid at a second pressure greater than the first pressure. Pressurized fluid is directed through a first passage to the outlet without the pressurized fluid leaving the pump head prior to reaching the outlet. A second passage directs pressurized fluid to a fluid circulation path which is at least partially external to the pump head with the fluid circulation path terminating adjacent the outlet. Pressurized fluid passing through the first and second passages is directed to the outlet without being re-pressurized by the pump head. The first and second passages are in opposed relation to one another to provide balancing of thrust produced by the flow of pressurized fluid through the passages. An electric motor drives the pump head. The fluid circulation path may include portions of the electric motor.

Fluid circulation path for motor pump

A pump head for a fluid pump driven by a motor includes an inlet for receiving fluid at a first pressure and an outlet for outputting fluid at a second pressure greater than the first pressure. A relief valve cavity formed in the pump head housing includes a first portion in fluid communication with the inlet and a second portion in fluid communication with the outlet. A relief valve is disposed in the relief valve cavity with no portion of the relief positioned to block or otherwise impede the normal flow of fluid through the inlet or outlet. The relief valve is bi-directional and configured to operate in two modes including: (1) a low pressure relief mode where fluid flows from the inlet to the outlet when fluid pressure at the inlet exceeds fluid pressure at the outlet by a first threshold amount; and (2) a high pressure relief mode where fluid flows from the outlet to the inlet when fluid pressure at the outlet exceeds fluid pressure at the inlet by a second threshold amount greater than the first threshold amount. The relief valve cavity is specially configured to provide a barrier preventing an element of the relief valve from damaging the pump head in the event the relief valve element fails.

Fluid pump relief valve

A motor pump is provided in which the motor rotor is optimally force balanced for enhanced operation. The motor pump includes a pump head for pressurizing a fluid, and an electric motor drives the pump head. High pressure fluid is circulated through the motor air gap. The shaft of the motor rotor is axially movable with respect to the pump head such that the motor rotor is effectively floated in high pressure fluid as the fluid flows through the motor.

Motor pump with balanced motor rotor

A fluid impermeable barrier is provided to protect the rotor of an electric motor. The barrier includes a body portion with a relatively large opening at one end to receive the rotor laminations and a smaller opening at the other end to receive one end of the rotor shaft. With the body portion positioned about the laminations, a cap with an outer perimeter and central opening is slid down the other end of the rotor shaft to close the large opening in the body portion. The assembly is completed by sealingly attaching the outer perimeter of the cap to the large opening in the body portion and sealingly attaching the smaller openings in the cap and body portion to respective portions of the rotor shaft. Thus, the fluid impermeable rotor barrier includes no more than two parts that are assembled onto the rotor using no more than three areas of attachment.

Fluid barrier for motor rotor

An apparatus for detecting the presence of an overheat condition in a fluid pump includes a pump head for receiving a fluid at a first pressure and outputting the fluid at a second pressure that is greater than the first pressure. A motor is positioned adjacent the pump head to drive the pump head to pressurize the fluid. A single overheat sensor senses an overheat condition in the pump head and an overheat condition in the motor. When a threshold temperature is sensed by the overheat sensor, a switch is activated to prevent operation of the motor. In one embodiment, the overheat sensor and switch are integral and may, for example, take the form of a bi-metal switch formed in the stator windings of the motor. In alternate embodiments, the overheat sensor and switch are separate.

Overheat protection for fluid pump

An apparatus for protecting a fluid pump motor includes an electric motor for driving a pump head to pressurize a fluid. A liner is positioned in the motor air gap to prevent pressurized fluid from contacting one or more magnetic field producing elements of the stator. The liner includes a thin wall to minimize the air gap distance. The liner wall is made thin enough that, under loading of the pressurized fluid, the liner wall deforms and bears against one or more of the field producing elements of the stator for structural support. The liner is preferably fabricated as a single metal part using a deep drawing process that results in a can having opposed open and closed ends with a substantially uniform cross-section between the open and closed ends of the can.

Growing community of inventors

Nashville, TN, United States of America

Robert E Harvey, Iii