A scroll compressor according to the present invention includes a casing having a hermetic inner space divided into a low pressure portion and a high pressure portion, an orbiting scroll disposed within the inner space of the casing and performing an orbiting motion, a non-orbiting scroll forming a compression chamber together with the orbiting scroll, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber, a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber, a valve accommodation groove formed on at least one of the non-orbiting scroll or the back pressure chamber assembly, a bypass hole formed from the intermediate pressure chamber into the valve accommodation groove in a penetrating manner, a check valve accommodated in the valve accommodation groove and opening and closing the bypass hole according to pressure of the intermediate pressure chamber, a communication passage communicating the valve accommodation groove and the low pressure portion with each other, and a control valve selectively opening and closing the communication passage, whereby a facilitated fabrication, improved responsiveness and relaxed restriction for a specification of a valve can be achieved.

A scroll compressor lubrication system and a scroll compressor are disclosed. The scroll compressor includes a capacity modulator, a lubricant opening, and a gas diverting passage. The capacity modulator is in fluid communication with compression pockets for selectively unloading gas from the pockets. The lubricant opening is in fluid communication with at least one bearing portion of the scroll compressor. Lubricant from the at least one bearing portion in the scroll compressor flows through the lubricant opening. The gas diverting passage includes an inlet and an outlet. The inlet of the gas diverting passage is in fluid communication with the capacity modulator, and the gas diverting passage extends below the lubricant opening such that gas from the outlet of the gas diverting passage can flow through a travel path of the lubricant that flows through the lubricant opening and entrains at least part of the lubricant to at least one bearing portion for lubrication.

A scroll compressor lubrication system and a scroll compressor are disclosed. The scroll compressor includes a capacity modulator, a lubricant opening, and a gas diverting passage. The capacity modulator is in fluid communication with compression pockets for selectively unloading gas from the pockets. The lubricant opening is in fluid communication with at least one bearing portion of the scroll compressor. Lubricant from the at least one bearing portion in the scroll compressor flows through the lubricant opening. The gas diverting passage includes an inlet and an outlet. The inlet of the gas diverting passage is in fluid communication with the capacity modulator, and the gas diverting passage extends below the lubricant opening such that gas from the outlet of the gas diverting passage can flow through a travel path of the lubricant that flows through the lubricant opening and entrains at least part of the lubricant to at least one bearing portion for lubrication.

Compression of water vapour as R718 is disclosed with and without addition of additives as an aqueous solution in rotational displacement machines, i.e. refrigeration, air-conditioning and heat pump technology. To largely avoid over or under-compression, it is proposed for the easiest possible adaptation of the currently effective internal volume ratio as so-called iV value in the displacer that the compressor housing starting from the outlet side with rotor profile length L.sub.R over a length L.sub.iV comprises planar, i.e. flat iV disks (3.sub.j) with the index j for 1?j?n; n is the number of disks; n?1 with a width b.sub.j per iV disk having planar surfaces P.sub.F preferably perpendicular to the neutral axis A.sub.N. The iV disks are displaced in a targeted manner individually by movement control devices (5.sub.j) per iV disk in each case by a distance s.sub.i where 0<s.sub.i?s.sub.j.

Compression of water vapour as R718 is disclosed with and without addition of additives as an aqueous solution in rotational displacement machines, i.e. refrigeration, air-conditioning and heat pump technology. To largely avoid over or under-compression, it is proposed for the easiest possible adaptation of the currently effective internal volume ratio as so-called iV value in the displacer that the compressor housing starting from the outlet side with rotor profile length L.sub.R over a length L.sub.iV comprises planar, i.e. flat iV disks (3.sub.j) with the index j for 1?j?n; n is the number of disks; n?1 with a width b.sub.j per iV disk having planar surfaces P.sub.F preferably perpendicular to the neutral axis A.sub.N. The iV disks are displaced in a targeted manner individually by movement control devices (5.sub.j) per iV disk in each case by a distance s.sub.i where 0<s.sub.i?s.sub.j.

Disclosed is a scroll compressor including: an orbiting scroll having an orbiting scroll end plate and an orbiting volute formed on one side of the orbiting scroll end plate, and a fixed scroll having a fixed scroll end plate and a fixed volute formed on one side of the fixed scroll end plate. The fixed and orbiting scrolls match each other in order to form a series of compression cavities therebetween including a central compression cavity and middle compression cavities located radially outside of the central compression cavity, and. The middle compression cavities include at least a set of a first middle compression cavity and a second middle compression cavity. A fluid channel selectively communicating with a discharge area is provided between the first and second middle compression cavities, and the first middle compression cavity directly communicates with the second middle compression cavity by means of the fluid channel.

Provided is a horizontal step scroll compressor with which liquid compression can be effectively prevented even when starting up from a liquid migration state in which liquid refrigerant has migrated into the compressor while operation of the compressor is stopped. In this horizontal step scroll compressor, bypass ports, which divert pressure into a discharge chamber when the pressure in a pair of compression chambers reaches or exceeds a set pressure at an intermediate compression position between a suction cutoff position and the position communicating with a discharge port, are provided along the spiral direction of spiral wraps. Among these bypass ports, the opening area of the bypass ports that open into the first compression chamber, which includes the step parts in the gravity direction when a step part and a step part, and a step part and a step part, begin to engage each other, is greater than the opening area of the bypass port, which opens to the second compression chamber forming a pair with the first compression chamber.

Provided is a horizontal step scroll compressor with which liquid compression can be effectively prevented even when starting up from a liquid migration state in which liquid refrigerant has migrated into the compressor while operation of the compressor is stopped. In this horizontal step scroll compressor, bypass ports, which divert pressure into a discharge chamber when the pressure in a pair of compression chambers reaches or exceeds a set pressure at an intermediate compression position between a suction cutoff position and the position communicating with a discharge port, are provided along the spiral direction of spiral wraps. Among these bypass ports, the opening area of the bypass ports that open into the first compression chamber, which includes the step parts in the gravity direction when a step part and a step part, and a step part and a step part, begin to engage each other, is greater than the opening area of the bypass port, which opens to the second compression chamber forming a pair with the first compression chamber.

The invention provides a pump comprising a pump inlet, a pump outlet, at least two threaded rotors and a pressure controlled valve, the pressure controlled valve being capable of controlling re-circulation of fluid from the pump outlet to the pump inlet. The pressure controlled valve can be a control valve. The invention also provides a multiple stage pump assembly comprising at least two pumps arranged in series, wherein at least one of the pumps is the aforementioned pump.

The invention provides a pump comprising a pump inlet, a pump outlet, at least two threaded rotors and a pressure controlled valve, the pressure controlled valve being capable of controlling re-circulation of fluid from the pump outlet to the pump inlet. The pressure controlled valve can be a control valve. The invention also provides a multiple stage pump assembly comprising at least two pumps arranged in series, wherein at least one of the pumps is the aforementioned pump.