The present disclosure provides a liquid suck-back system and a liquid suck-back method, and belongs to the technical field of suck-back of liquid. The liquid suck-back system includes a suck-back pipeline and a suck-back pump. The suck-back pipeline includes a first port and a second port, the first port is connected to the suck-back pump, and the second port is connected to a liquid supply pipeline. The suck-back pipeline includes a suck-back valve and a water return bay, the liquid supply pipeline is configured to supply liquid chemicals, and the suck-back pump is configured to suck back residual liquid chemicals in the liquid supply pipeline when the liquid supply pipeline stops supplying liquid chemicals.

Systems and methods for reducing the pressure of a first pressurized fluid, thereby reducing the temperature of the pressurized fluid, and utilization of the reduced-pressure and temperature fluid to cool a second fluid. Such an approach can enable a reduction in the size and weight of a hydraulic system, utilize waste energy in a system, and/or minimize electrical power requirements of a system, among other benefits.

A submersible pump providing an impeller pump assembly, an aerator pump assembly, a central hub assembly, and a nozzle assembly. The combination or integration of two independently driven, high-pressure impeller pump assembly and high-volume pump aerator pump assembly simultaneously coacting within the same submersible pump apparatus and using the central hub assembly and nozzle assembly to create and display the combination of very tall streams while simultaneously displaying a wide variety of other beautiful high-volume or flow display aerator spray patterns

An illustrative example embodiment of a compressor assembly includes a compressor housing having a suction inlet and a discharge outlet. A flow restricting valve allows unrestricted fluid flow in a first direction into the housing through the suction inlet and out of the discharge outlet during a first operating condition. The flow restricting valve allows a restricted fluid flow in a second, opposite direction into the housing through the discharge outlet in a second operating condition.

The disclosed invention improves on self-priming centrifugal pumps. The improvements facilitate ease of maintenance by allowing the vacuum pulley belt to be changed without the need to disassemble the centrifugal pump to access the vacuum pulley belt. Additionally, issues with float valves becoming restricted leading to loss of prime conditions can be corrected with a disclosed invention.

A hydraulic valve device includes a first inlet port (20) and a second inlet port (22) and a valve element (24) for selectively closing one of the first and the second inlet port. The valve element (24; 24′) is rotatable between two valve positions such that a surface of the valve element is moved in a direction parallel to openings of the inlet ports. The valve element includes two separate sealing portions (72, 74), a first sealing portion (72) for closing the first inlet port and a second sealing portion (74) for closing the second inlet port. The two sealing portions are arranged such that in a first valve position a first sealing portion closes the first inlet port and in a second valve position a second sealing portion closes the second inlet port. A centrifugal pump device includes such hydraulic valve device.

A hydraulic system includes a circulation pump assembly (2) provided with a speed controller (4, 26), a hydraulic circuit (A, B) connected to the circulation pump assembly (2) as well as a mechanical switch device (86, 88; 120, 122; 120″, 122″) which is subjected to pressure from a fluid in the hydraulic circuit (A, B) and which can be moved into at least two different switch positions. The mechanical switch device (28; 86, 28; 120, 122) can be moved by the circulation pump assembly (2) by way of a hydraulic coupling via the fluid. The speed controller is configured to initiate a movement of the switch device (86, 88; 120, 122; 120″, 122″) by way of at least one hydraulic force acting thereon and causing a movement of the switch device (86, 88; 120,122; 120″, 122″), produced via the hydraulic circuit, via a speed adaptation of the circulation pump assembly.

A centrifugal pump assembly includes an electric drive motor (6, 8), a driven impeller (14) and a pump casing (2) which surrounds the impeller (14). A movable element (24; 24′) is arranged a valve element. A section of the valve element is movable from a released position into a bearing position, fixed on a contact surface (60), by pressure which is produced by the impeller in the pump casing. A control device (64) moves the valve element from one switching position into another switching position and reduces the speed of the drive motor. Upon pressure in the pump casing dropping such that the valve element is no longer fixed on the contact surface and the valve element has been moved into the other switching position, the control device increases the speed of the drive motor again. A method for moving a valve element is provided.

An electric priming pump device detachably couples to a centrifugal water pump on the suction side of the water pump, for priming thereof. The device comprises an enclosure and a base, wherein the enclosure contains a rotary vane peripheral bypass vacuum motor which is pressed against the base to form an air-tight seal. The device generates a vacuum for priming through use of a rotary vane peripheral bypass vacuum motor, which can remove large volumes of air quickly. An opening in the base receives a check valve fitting to protect the motor from water and slows loss of vacuum pressure after use. Additionally, a cone shaped protective cover protects components in the device and provides space for branding or advertisement.

A hydraulic system includes at least one circulation pump assembly (2) provided with a speed controller (4, 26), at least one hydraulic circuit (A, B) connected to the circulation pump assembly (2) as well as at least one mechanical switch device (86, 88; 120, 122) which is mechanically subjected to pressure by a fluid in the hydraulic circuit (A, B) and which can be moved into at least two different switch positions. The mechanical switch device (86, 88; 120, 122) moves by the circulation pump assembly (2) hydraulic coupling via the fluid. The speed controller is configured to initiate a movement of the switch device (86, 88; 120, 122), by at least one hydraulic force acting upon the switch device (86, 88; 120, 122) and causing a movement of the switch device (86, 88; 120; 122) via the hydraulic circuit, via a speed adaptation of the circulation pump assembly (2).