A lubricant filler for a lubricant tank of an aircraft engine comprises a filler tube having an upper portion to be disposed outside the volume of the tank and a lower portion to be disposed inside the volume. First and second openings are respectively provided in the upper and lower portions. An oil volume sensor is received in the filler tube through the first opening. A valve is connected to the filler tube and movable between an open position in which the valve provides a fluid connection into the lower portion via the second opening, and a closed position in which the valve blocks the fluid connection into the lower portion via the second opening. A third opening, smaller than both the first and second openings, defined one of: a) through a sidewall of the lower portion of the filler tube to provide a fluid connection between the volume and the lower portion when the lubricant filler assembly is attached to the lubricant tank, and b) through the valve to provide the fluid connection when the lubricant filler assembly is attached to the lubricant tank.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

Systems and methods for automatic maintenance of lube oil quality include a storage tank for storing fresh lube oil, a lube oil reservoir containing a volume of operational lube oil, and an oil disposal tank. A first controllable flow system transports lube oil from the reservoir to the oil disposal tank, and a second controllable flow system transports fresh lube oil from the storage tank to the reservoir. Provided are a level transmitter to measure a level of lube oil within the reservoir and an antioxidant sensor to measure a concentration of antioxidant level inside the lube oil reservoir. A control system activates and deactivates the first controllable flow system based upon the concentration of antioxidant measured by the antioxidant sensor, and activates and deactivates the second controllable flow system based upon the level of lube oil measured by the level transmitter.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

Systems and methods for automatic maintenance of lube oil quality include a storage tank for storing fresh lube oil, a lube oil reservoir containing a volume of operational lube oil, and an oil disposal tank. A first controllable flow system transports lube oil from the reservoir to the oil disposal tank, and a second controllable flow system transports fresh lube oil from the storage tank to the reservoir. Provided are a level transmitter to measure a level of lube oil within the reservoir and an antioxidant sensor to measure a concentration of antioxidant level inside the lube oil reservoir. A control system activates and deactivates the first controllable flow system based upon the concentration of antioxidant measured by the antioxidant sensor, and activates and deactivates the second controllable flow system based upon the level of lube oil measured by the level transmitter.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.

A lubricant recovery system for a heat exchange system, and a heat exchange system. The heat exchange system includes a compressor, a condenser, an expansion device and an evaporator connected in sequence to form a loop, and further includes a reservoir for storing lubricant and in communication with the compressor, and the lubricant recovery system includes: a first flow path disposed between a suction chamber of the compressor and the reservoir, and having a first pump and a first filter, wherein the first pump is configured to pump a part of the lubricant in the suction chamber to the reservoir, and the first filter is disposed upstream of the first pump for filtering the lubricant; and/or a second flow path disposed between the evaporator and the suction chamber, and having a second pump and a second filter.

Embodiments of systems and methods disclosed provide a hydraulic fracturing unit that includes a reciprocating plunger pump configured to pump a fracturing fluid and a powertrain configured to power the reciprocating plunger pump. The powertrain includes a prime mover and a drivetrain, the prime mover including a gas turbine engine. The hydraulic fracturing unit also includes auxiliary equipment configured to support operation of the hydraulic fracturing unit including the reciprocating plunger pump and the powertrain. A power system is configured to power the auxiliary equipment. The power system includes a power source and a power network. The power source is configured to generate power for the auxiliary equipment. The power network is coupled to the power source and the auxiliary equipment, and configured to deliver the power generated by the power source to the auxiliary equipment. Associated systems including a plurality of hydraulic fracturing units are also provided.