A built-in water pumping device of a manual paddle for a boat contains: a shaft, a blade, and a water absorption head. The shaft includes an inner tube and an outer tube movably fitted with the inner tube so as to movably adjust a length of the shaft, thus pumping waters. An adjustable fitting sleeve is configured to lock or unlock the inner tube and the outer tube after adjusting the length of the shaft. The shaft includes a receiving chamber. A water absorption head is fixed on the outer tube and has a passing orifice. The blade includes at least one outlet communicating with the receiving chamber, such that the inner tube is actuated to absorb the waters into the receiving chamber from the passing orifice, and the inner tube is pulled back and forth so that the waters discharge out of the at least one outlet continuously.

Systems and methods to enhance the flow of fracturing fluid into a wellhead during a high-pressure fracturing operation may include providing a pump frame and a crankshaft. A plurality of first plungers may be connected to the crankshaft and may reciprocate in a first plane. The hydraulic fracturing pump also may include a plurality of second plungers connected to the crankshaft and positioned to reciprocate in a second plane. The first plane and the second plane may define a non-zero offset angle between the first plane and the second plane. The crankshaft may include a plurality of crankpins, and each of the crankpins may be connected to one of the first plungers and one of the second plungers. The first plungers may pump a first fracturing fluid and the second plungers may pump a second fracturing fluid different from the first fracturing fluid.

Systems and methods to enhance the flow of fracturing fluid into a wellhead during a high-pressure fracturing operation may include providing a pump frame and a crankshaft. A plurality of first plungers may be connected to the crankshaft and may reciprocate in a first plane. The hydraulic fracturing pump also may include a plurality of second plungers connected to the crankshaft and positioned to reciprocate in a second plane. The first plane and the second plane may define a non-zero offset angle between the first plane and the second plane. The crankshaft may include a plurality of crankpins, and each of the crankpins may be connected to one of the first plungers and one of the second plungers. The first plungers may pump a first fracturing fluid and the second plungers may pump a second fracturing fluid different from the first fracturing fluid.

Disclosed techniques include working fluid exergy recovery using hybrid processing. A supply of working fluid at a first pressure and a first temperature is accessed. The working fluid is compressed. The compressing yields the working fluid at a second pressure. The second pressure is greater than the first pressure. The working fluid at the second pressure and a second temperature is warmed using a first heat exchanger. The second temperature is greater than the first temperature. The working fluid at the second temperature is in a gaseous state. The working fluid is expanded in a gaseous state to a third pressure. The expanding is accomplished using a first liquid piston expander. An engine is driven to recover work from the working fluid in a gaseous state. The engine is powered by liquid from the first liquid piston expander.

Disclosed techniques include working fluid exergy recovery using hybrid processing. A supply of working fluid at a first pressure and a first temperature is accessed. The working fluid is compressed. The compressing yields the working fluid at a second pressure. The second pressure is greater than the first pressure. The working fluid at the second pressure and a second temperature is warmed using a first heat exchanger. The second temperature is greater than the first temperature. The working fluid at the second temperature is in a gaseous state. The working fluid is expanded in a gaseous state to a third pressure. The expanding is accomplished using a first liquid piston expander. An engine is driven to recover work from the working fluid in a gaseous state. The engine is powered by liquid from the first liquid piston expander.

A fracturing apparatus is provided. The fracturing apparatus includes: a plunger pump including a hydraulic end and a power end, the power end having a power end oil outlet and at least one power end oil inlet that are coupled to each other; and a power end lubricating system, including: a lubricating oil tank configured for defining an accommodation space, at least one lubrication pump having a lubrication pump oil inlet and a lubrication pump oil outlet that are coupled to each other, and at least one lubrication motor configured for providing power for the at least one lubrication pump, wherein at least a portion of at least one of the lubrication motor and the lubrication pump is located in the accommodation space.

A power end assembly includes a crankshaft section, a crosshead section, and a connector section coupled together by one, two, or more sets of stay rods. The power end may include one or more support plates that are coupled to the crankshaft section and/or crosshead section. The crosshead section includes a plurality of individual crosshead frames. The connector section may include a plurality of individual connector plates or may be a unitary connector plate. The power end is configured to be coupled to a fluid end assembly by coupling the fluid end assembly to the connector plates.

Systems and methods to enhance the flow of fracturing fluid into a wellhead during a high-pressure fracturing operation may include providing a pump frame and a crankshaft. A plurality of first plungers may be connected to the crankshaft and may reciprocate in a first plane. The hydraulic fracturing pump also may include a plurality of second plungers connected to the crankshaft and positioned to reciprocate in a second plane. The first plane and the second plane may define a non-zero offset angle between the first plane and the second plane. The crankshaft may include a plurality of crankpins, and each of the crankpins may be connected to one of the first plungers and one of the second plungers. The first plungers may pump a first fracturing fluid and the second plungers may pump a second fracturing fluid different from the first fracturing fluid.

Systems and methods to enhance the flow of fracturing fluid into a wellhead during a high-pressure fracturing operation may include providing a pump frame and a crankshaft. A plurality of first plungers may be connected to the crankshaft and may reciprocate in a first plane. The hydraulic fracturing pump also may include a plurality of second plungers connected to the crankshaft and positioned to reciprocate in a second plane. The first plane and the second plane may define a non-zero offset angle between the first plane and the second plane. The crankshaft may include a plurality of crankpins, and each of the crankpins may be connected to one of the first plungers and one of the second plungers. The first plungers may pump a first fracturing fluid and the second plungers may pump a second fracturing fluid different from the first fracturing fluid.

In accordance with at least one aspect of this disclosure, a variable displacement pump system can include, a variable displacement pump disposed in a main line and configured to supply pressure to receive a low pressure fluid and to output a high pressure fluid. The main line can connect a hydraulic fluid source to a plurality of system actuators, where the variable displacement pump is disposed in the main line between the hydraulic fluid source and the plurality of system actuators to pressurize the hydraulic fluid.