A system may include a first compressor, a second compressor, a first heat exchanger and a second heat exchanger. The first compressor has a first inlet and a first outlet. The second compressor is a sumpless compressor and has a second inlet and a second outlet. The second compressor provides working fluid discharged from the second outlet to the first compressor. The first heat exchanger is disposed upstream of the second compressor and provides working fluid to the second compressor. The second heat exchanger is disposed upstream of the first compressor and provides working fluid to the first compressor.

Systems and methods for providing lubricant from a first compressor to a second compressor are provided. A control module receives a start command for a climate-control system having the first and second compressors, allows lubricant from the first compressor to flow into an inlet of the second compressor, turns the second compressor to an ON-mode, and prevents lubricant from the first compressor from flowing into the inlet of the second compressor after the second compressor has been in the ON-mode for a predetermined time period.

A gas-side stop valve on the gas refrigerant side and a liquid-side stop valve on the liquid refrigerant side are provided in a package of an outdoor unit. A gas-side filter on the gas refrigerant side is mounted on the indoor unit side relative to the gas-side stop valve and inside the package of the outdoor unit. A liquid-side filter 9 on the liquid refrigerant side is mounted on the indoor unit side relative to the liquid-side stop valve and inside the package of the outdoor unit. As a result, it is not necessary to ensure a place for mounting the gas-side filter and the liquid-side filter at the time of installation on site and the workability can be improved.

A subcooler is made up of a plate type heat exchanger. The accumulator is located between a compressor and the subcooler in a width direction of an outdoor unit in a planar view. The subcooler overlaps with the accumulator in the width direction in the planar view. As a result, a compact heat pump can be provided when the subcooler is a plate type heat exchanger.

A system may include a first compressor, a second compressor, a first heat exchanger and a second heat exchanger. The first compressor has a first inlet and a first outlet. The second compressor is a sumpless compressor and has a second inlet and a second outlet. The second compressor provides working fluid discharged from the second outlet to the first compressor. The first heat exchanger is disposed upstream of the second compressor and provides working fluid to the second compressor. The second heat exchanger is disposed upstream of the first compressor and provides working fluid to the first compressor.

The present invention relates to a linear compressor. The linear compressor according to an aspect of the present invention includes a spring axially elastically supporting a driving assembly. The spring includes a spring body axially extending, a front spring link forming an end of the spring body by extending from a side of the spring body, and a rear spring link forming the other end of the spring body by extending from the other side of the spring body. Any one of the front spring link and the rear spring link is fixed to the driving assembly and the other one is fixed to a supporting assembly.

Various assemblies that can be used in a mud pump with a plunger-style piston to reduce seal failures, to offer control in variability of the circumference of the piston to thereby control fluid pressure, and to provide visibility into seal condition during operation. In one embodiment, a sleeve that can vary the overall effective circumference of the piston enables fluid pressure control. In some embodiments, seal failure within a pump can be monitored via a drain port that would receive drilling fluid leaking past a seal during operation of the pump. A discharge valve can be provided between an inlet and an outlet of the mud pump to reduce the load on pump components during start-up. Additional systems, devices, and methods are also disclosed.

A liquid-feed-type gas compressor that can monitor the liquid surface height in a gas-liquid separator is provided. An oil-feed-type air compressor includes: an oil separator that separates oil from compressed air discharged from a compressor main body 1 and stores the oil therein; a sampling line whose inlet side is connected to a predetermined height position of the oil separator and that allows fluid from the predetermined height position of the oil separator to flow by the pressure difference between the inlet side and the outlet side; a pressure sensor that detects the pressure of the fluid that flows or has flown in the sampling line; a controller that determines which of air and oil the fluid that flows in the sampling line is by carrying out determination of whether the pressure detected by the pressure sensor exceeds a set value P1 in some cases and determination of whether the pressure falls below a set value P2 in some cases; and an informing device that informs a determination result of the controller.

A gas-side stop valve on the gas refrigerant side and a liquid-side stop valve on the liquid refrigerant side are provided in a package of an outdoor unit. A gas-side filter on the gas refrigerant side is mounted on the indoor unit side relative to the gas-side stop valve and inside the package of the outdoor unit. A liquid-side filter 9 on the liquid refrigerant side is mounted on the indoor unit side relative to the liquid-side stop valve and inside the package of the outdoor unit. As a result, it is not necessary to ensure a place for mounting the gas-side filter and the liquid-side filter at the time of installation on site and the workability can be improved.

A subcooler is made up of a plate type heat exchanger. The accumulator is located between a compressor and the subcooler in a width direction of an outdoor unit in a planar view. The subcooler overlaps with the accumulator in the width direction in the planar view. As a result, a compact heat pump can be provided when the subcooler is a plate type heat exchanger.