A self-priming pump assembly comprises a series connection of a liquid ring pump functioning as a rotating displacement pump and a normally-priming centrifugal pump. The self-priming pump assembly improves the fluid mechanics conditions for the flow of fluids toward and into a return line through the inclusion of a first connection opening in the meridian plane of the centrifugal pump that possesses a bulge enclosing a sector of the longitudinal axis of the first connection opening, where the bulge is one-sided and oriented toward a rotary axis of the pump assembly, and the bulge continuously expands, directly or indirectly, the first connection opening toward the impeller plane. At its end section facing the impeller plane, a transitional surface of the bulge continuously transitions into the lateral boundary surface, or an inner peripheral wall of the ring channel adjoining the lateral boundary surface.

A centrifugal pump assembly (2) includes an impeller, an electric drive motor (4), driving the impeller (12), and a back-flow channel (24), forming a flow connection from a delivery side (18) to a suction side (16). A valve (26), in a pressure-dependent manner, closes the flow connection. A control device (28) adjusts/sets the speed (n) of the drive motor (4), and is configured with a venting function for venting the centrifugal pump assembly (2) on operation. According to the venting function, after the detection of an air accumulation, the speed (n) of the drive motor (4) is automatically reduced, and subsequently the speed (n) is rapidly increased again. A method is also provided for removing an air accumulation from a centrifugal pump assembly during operation, which method includes reducing the speed (n) of the centrifugal pump assembly and subsequently rapidly increasing the speed (n) of the centrifugal pump again.

A multiphase pump includes a housing having a pump inlet and a pump outlet for a process fluid, an inlet annulus configured to receive the process fluid from the pump inlet, a discharge annulus configured to discharge the process fluid into the pump outlet, a pump rotor configured to rotate about an axial direction and arranged within the housing, the pump rotor being configured to convey the process fluid from the inlet annulus to the outlet annulus, and a return line configured to return the process fluid from the high pressure side to the low pressure side, the return line including an inlet configured to receive the process fluid, an outlet configured to discharge the process fluid and a control valve configured to open and close the return line, the inlet of the return line arranged directly at the discharge annulus.

A quick no-water startup apparatus for a centrifugal pump includes, from top to bottom in sequence, one-way passages (1), a self-priming chamber housing (41), sliding devices (5), a self-priming chamber (4), chamber partition plates (2) a concave-convex impeller (3), inlet channels (6) connected on two sides of the self-priming chamber (4), a spring device (7) of an upper-side x-shaped gas-liquid separation device, the upper-side x-shaped gas-liquid separation device (8), upper and middle-side gas-liquid separation device connecting shafts (9), a middle-side gas-liquid separation device (10), lower-side backflow-type gas-liquid separation devices (11), v-shaped backflow channels (122), an inverted v-shaped inlet channel (121), and an inlet. The quick no-water startup apparatus of the present invention enables the centrifugal pump to directly enter a normal operating condition after no-water startup, and 36 times of air exhaust can be completed while the concave-convex impeller (3) in the self-priming chamber (4) rotates by a circle in the early stage. Besides, the apparatus is provided with the upper, middle, and lower gas-liquid separation devices to fully realize separation of gas and liquid, so that gas can be exhausted more quickly and the chamber is filled with water. Therefore, the working efficiency is significantly improved and the operation process is greatly simplified.

A reconfigurable pump includes a housing with inlet and outlet openings. An inlet adapter is mounted on the housing and includes an inlet passage communicating with the inlet opening. The inlet adapter is removably mounted on the housing and can be removed and repositioned for reconfiguring the pump between low-inlet and high-inlet configurations. In a low-inlet configuration the inlet passage is generally aligned with an impeller rotatably mounted in the housing. A check valve comprising a flapper valve is provided in the low-inlet configuration and prevents backflow. The flapper valve is removable for configuration in a high-inlet configuration with the inlet passage located generally above the impeller level. The inlet adapter can readily be repositioned from outside the pump housing between its low-inlet and high-inlet configurations.

A multi-stage, self-priming centrifugal pump assembly includes at least two pump stages (4) which are consecutive in a main flow direction (32), and a backflow channel (13) which lies parallel to at least one a pump stage (4). The backflow channel (13) runs out downstream of the first or a further pump stage (4), in the main flow direction (32).

The invention relates to a diaphragm wall cutter for cutting a cutting trench in the ground, comprising a cutting frame, at least one rotatably drivable cutting wheel which is mounted on an lower side of the cutting frame, a suction nozzle, which is arranged in the region of the at least one cutting wheel and is provided with at least one suction opening, and a suction pump which is configured for suctioning slurry from the cutting trench during cutting via the suction nozzle, the suction pump being connected to the suction nozzle via a suction line. According to the invention, it is provided that at least one filling port is provided for filling the suction pump and the suction line with a liquid when the suction line is shut-off, wherein the suction line and the suction pump are filled with liquid for starting the suction pump.

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 pump assembly comprises a series connection of a liquid ring pump functioning as a rotating displacement pump and a normally-priming centrifugal pump. The self-priming pump assembly improves the fluid mechanics conditions for the flow of fluids toward and into a return line through the inclusion of a first connection opening in the meridian plane of the centrifugal pump that possesses a bulge enclosing a sector of the longitudinal axis of the first connection opening, where the bulge is one-sided and oriented toward a rotary axis of the pump assembly, and the bulge continuously expands, directly or indirectly, the first connection opening toward the impeller plane. At its end section facing the impeller plane, a transitional surface of the bulge continuously transitions into the lateral boundary surface, or an inner peripheral wall of the ring channel adjoining the lateral boundary surface.

A system for maintaining a prime of a pump includes a suction line, a discharge line, a pump line, a bypass line, and a pressure tank connected to the bypass line. The pump line includes a pump, an inlet in communication with the suction line, and a discharge in communication with the discharge line. The pump is operable to propel fluid from the suction line to the discharge line through the pump line. The bypass line extends from the suction line to the discharge line. The bypass line includes a control valve operable to selectively permit fluid to flow through the bypass line from the discharge line to the suction line.