A well fluid centrifugal pump has a shaft passage in the shaft. The shaft passage has an open upper end above the impellers and a closed lower end below the impellers. An outlet port extends laterally from the shaft passage. A gas-lock re-priming device in the shaft passage diverts a portion of well fluid in the discharge adapter bore through the shaft passage and out the outlet port. The re-priming device may be a pressure actuated valve that is biased to a closed position and opens when the pressure in the discharge adapter bore drops below a minimum. Alternately, the re-priming device may be an orifice member with an orifice passage that continuously diverts a portion of the well fluid in the discharge adapter bore out the outlet port.

A well fluid centrifugal pump has a shaft passage in the shaft. The shaft passage has an open upper end above the impellers and a closed lower end below the impellers. An outlet port extends laterally from the shaft passage. A gas-lock re-priming device in the shaft passage diverts a portion of well fluid in the discharge adapter bore through the shaft passage and out the outlet port. The re-priming device may be a pressure actuated valve that is biased to a closed position and opens when the pressure in the discharge adapter bore drops below a minimum. Alternately, the re-priming device may be an orifice member with an orifice passage that continuously diverts a portion of the well fluid in the discharge adapter bore out the outlet port.

A centrifugal pump (7), with one or more pumping stages, includes a pressure controlled valve (15) inside the pump (7) for supporting self-priming, the pressure controlled valve (15). The pressure controlled valve (15) includes a pretensioned leaf spring (17) and a valve seat (18). The leaf spring (17) has an opened position and a closed position. In the open position the leaf spring (17) is distanced from the valve seat (18). In the closed position the leaf spring (17) closes the valve seat (18). The leaf spring (17) and valve seat (18) are arranged for soft closing.

A centrifugal pump (7), with one or more pumping stages, includes a pressure controlled valve (15) inside the pump (7) for supporting self-priming, the pressure controlled valve (15). The pressure controlled valve (15) includes a pretensioned leaf spring (17) and a valve seat (18). The leaf spring (17) has an opened position and a closed position. In the open position the leaf spring (17) is distanced from the valve seat (18). In the closed position the leaf spring (17) closes the valve seat (18). The leaf spring (17) and valve seat (18) are arranged for soft closing.

A hemispherical entrainment-type high-flow self-priming centrifugal pump includes a hemispherical entrainment system, a pump body and a pump inlet pipe. The hemispherical entrainment system is disposed above the pump body. The hemispherical entrainment system comprises four layers of entrainment cavities, including a spherical entrainment interior cavity, a primary entrainment cavity, a secondary entrainment cavity and a tertiary entrainment cavity. The spherical entrainment interior cavity is a double circular pipeline that ascends in a spiral overlapping manner to wrap a hemispherical surface, and improves the entrainment capacity, while increasing the entrainment area. The primary entrainment cavity is allowed to be in communication with the secondary entrainment cavity and the tertiary entrainment cavity by upward sliding of a sliding check core. The secondary entrainment cavity entrains the gas in the pump inlet pipe, and the primary entrainment cavity entrains the gas in a pump cavity.

A hemispherical entrainment-type high-flow self-priming centrifugal pump includes a hemispherical entrainment system, a pump body and a pump inlet pipe. The hemispherical entrainment system is disposed above the pump body. The hemispherical entrainment system comprises four layers of entrainment cavities, including a spherical entrainment interior cavity, a primary entrainment cavity, a secondary entrainment cavity and a tertiary entrainment cavity. The spherical entrainment interior cavity is a double circular pipeline that ascends in a spiral overlapping manner to wrap a hemispherical surface, and improves the entrainment capacity, while increasing the entrainment area. The primary entrainment cavity is allowed to be in communication with the secondary entrainment cavity and the tertiary entrainment cavity by upward sliding of a sliding check core. The secondary entrainment cavity entrains the gas in the pump inlet pipe, and the primary entrainment cavity entrains the gas in a pump cavity.

A self-priming jet pump includes a pump body provided with a water inlet and a water outlet. A jet tube and an impeller are arranged in the pump body. The jet tube is communicated with the water inlet and an inlet of an impeller. A first channel is arranged on the outer periphery of the jet tube. The first channel is communicated with the water inlet and the impeller. A cross-section of the first channel is a closed or open annular structure, and the first channel is around the outer periphery of the jet tube. The first channel is provided with a valve core. When a pressure at the water inlet is greater than a predetermined pressure at the impeller, the valve core moves to switch on the first channel. A cavitation problem is relieved by arranging the flow-increasing channel.

A self-priming jet pump includes a pump body provided with a water inlet and a water outlet. A jet tube and an impeller are arranged in the pump body. The jet tube is communicated with the water inlet and an inlet of an impeller. A first channel is arranged on the outer periphery of the jet tube. The first channel is communicated with the water inlet and the impeller. A cross-section of the first channel is a closed or open annular structure, and the first channel is around the outer periphery of the jet tube. The first channel is provided with a valve core. When a pressure at the water inlet is greater than a predetermined pressure at the impeller, the valve core moves to switch on the first channel. A cavitation problem is relieved by arranging the flow-increasing channel.

Technologies are generally described for pump devices that include an adaptive cutwater and impeller arrangement. The power end of the pump device can be coupled to a motor to drive an impeller. The primer plate and impeller of the pump device are removable from the pump casing such that the primer plate and impeller can be replaced or modified as desired for different applications. In some examples, the pump casing includes a primer plate that is removable from the pump casing, where the primer plate includes a discharge cutwater tongue that is specifically spaced and sized to service an impeller of a desired design. The discharge cutwater tongue and impellers in the pump device may thus be serviced for replacement parts, as well as to modify the pump device for different fluids of different fluids properties or hydraulic requirements as may be needed in different applications.

Technologies are generally described for pump devices that include an adaptive cutwater and impeller arrangement. The power end of the pump device can be coupled to a motor to drive an impeller. The primer plate and impeller of the pump device are removable from the pump casing such that the primer plate and impeller can be replaced or modified as desired for different applications. In some examples, the pump casing includes a primer plate that is removable from the pump casing, where the primer plate includes a discharge cutwater tongue that is specifically spaced and sized to service an impeller of a desired design. The discharge cutwater tongue and impellers in the pump device may thus be serviced for replacement parts, as well as to modify the pump device for different fluids of different fluids properties or hydraulic requirements as may be needed in different applications.