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.

A rotary drive system includes an electric motor, a speed reducer, and a lubricating oil-circulating unit. The electric motor has an electric motor casing forming a first accommodating space and a communication hole communicating downward. The speed reducer has a speed reducer casing forming a second accommodating space communicating with the first accommodating space through the communication hole. The lubricating oil-circulating unit has a lubricating oil flow path and a lubricating oil pump. The lubricating oil flow path connects the first accommodating space and the second accommodating space at the outside. The lubricating oil pump pumps lubricating oil from the second accommodating space side to the first accommodating space side.

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.

In the method according to the invention for operating an oil level regulator on a compressor, the oil level regulator monitors an oil level in the compressor and causes oil to be refilled when an oil deficiency is recognized. The oil level regulator provides operating recognition of the compressor in which a check is made as to whether the compressor is in a switched-on or switched-off state, the refilling with oil being carried out only when the compressor is in the switched-on state.

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 climate-control system may include first and second compressors and a suction manifold. The first compressor includes a first shell, a first compression mechanism, and a first suction inlet through which working fluid is drawn into the first compressor. The second compressor includes a second shell, a second compression mechanism, and a second suction inlet through which working fluid is drawn into the second compressor. The suction manifold includes first and second arms. The first arm provides working fluid to the first suction inlet. The second arm provides working fluid to the second suction inlet. The second arm includes a first suction pipe, a second suction pipe, and a suction valve. The suction valve is movable between a first position in which working fluid is allowed to flow through the first suction pipe and a second position in which working fluid is allowed to flow through the second suction pipe.

A method for supplying cutting oil in a machine tool for cutting work pieces, including the steps of retaining cutting oil in a minimum reference quantity or an initial reference quantity in the cutting-oil tank, measuring a supply quantity per unit time q of the cutting oil flowing out from the cutting-oil tank and supplied to a cutting area of work pieces, either supplying the cutting oil to the cutting-oil tank by a quantity per unit time q larger than q and the supply is stopped in the case where the cutting-oil tank is filled, and the supplying and stopping are repeated as necessary, or supplying the cutting oil to the cutting-oil tank by a quantity per unit time equal to the supply quantity per unit time q.

A method for supplying cutting oil in a machine tool for cutting work pieces, including the steps of retaining cutting oil in a minimum reference quantity or an initial reference quantity in the cutting-oil tank, measuring a supply quantity per unit time q of the cutting oil flowing out from the cutting-oil tank and supplied to a cutting area of work pieces, either supplying the cutting oil to the cutting-oil tank by a quantity per unit time q larger than q and the supply is stopped in the case where the cutting-oil tank is filled, and the supplying and stopping are repeated as necessary, or supplying the cutting oil to the cutting-oil tank by a quantity per unit time equal to the supply quantity per unit time q.

A lubricating oil system includes a reservoir configured to enclose a lubricant oil; a filter assembly that includes at least one filter and is positioned in the reservoir to separate the reservoir into a first oil tank and a second oil tank, where the first oil tank fluidly is coupled to the rotating machine through an oil return line; a system pump fluidly coupled to the reservoir and configured to circulate the lubricant oil from the second oil tank to the rotating machine through an oil supply line; and a circulating pump assembly. The circulating pump assembly includes a conduit that fluidly couples the first oil tank to the second oil tank external to the reservoir, a circulating pump coupled within the conduit and including a suction coupled to the first oil tank and a discharge coupled to the second oil tank, and a media filter coupled within the conduit and between the first oil tank and the second oil tank.

In the method according to the invention for operating an oil level regulator on a compressor, the oil level regulator monitors an oil level in the compressor and causes oil to be refilled when an oil deficiency is recognized. The oil level regulator provides operating recognition of the compressor in which a check is made as to whether the compressor is in a switched-on or switched-off state, the refilling with oil being carried out only when the compressor is in the switched-on state.