Abstract: In an oil-cooled screw compressor, a tooth crest arc of a fixed width is provided to the tooth crest of a male tooth profile, and simultaneously a tooth bottom arc is provided to the tooth bottom of a female tooth profile. Due to the actions thereof, the operation chamber immediately before disappearing exists only in a bottom half region from a line that connects the centers of the male and female tooth profiles, and the opening area relative to the volume of the operation chamber can be increased. As a result, the discharge of oil becomes smooth and energy loss is reduced.

Abstract: The objective of the present invention is to reduce loss factors that occur inside an oil-cooled screw compressor and to improve energy efficiency. In oil-cooled screw compressors, compression is carried out by reducing the volume of an operation chamber in which a gas to be compressed and an oil are mixed and contained, and when a predetermined rise in pressure is complete, a discharge port opens and the gas to be compressed and the oil are discharged. In the operation chamber, the reduction in volume continues and reaches zero, such that the operation chamber disappears, and the opening area of the discharge port also gradually decreases. Immediately before the operation chamber disappears, the ratio of the oil within the operation chamber is high and the opening area of the discharge port is small. Therefore, the discharge resistance increases and the internal pressure dramatically rises, and this has led to increases in the torque rotating the rotor.

Abstract: A high reliability water injected scroll air compressor is provided with an orbiting scroll, a fixed scroll corresponding to the orbiting scroll, a motor that generates driving force for making the orbiting scroll orbit the fixed scroll, a compressing path from a suction port to a discharge port, and a portion for injecting water into the compressing path. The operation is controlled by a switching operation in which water is injected into the compressing path and then no water is injected. Corrosion, failure of activation, and concerns about wrap contact when water is injected into an air end are avoided by switching the operation with water injection and the operation without water injection so as to prevent water from remaining in the air end.

Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: A high reliability water injected scroll air compressor is provided with an orbiting scroll, a fixed scroll corresponding to the orbiting scroll, a motor that generates driving force for making the orbiting scroll orbit the fixed scroll, a compressing path from a suction port to a discharge port, and a portion for injecting water into the compressing path. The operation is controlled by a switching operation in which water is injected into the compressing path and then no water is injected. Corrosion, failure of activation, and concerns about wrap contact when water is injected into an air end are avoided by switching the operation with water injection and the operation without water injection so as to prevent water from remaining in the air end.

Abstract: As pressure in a water tank rapidly rises when water inside a compressor is evaporated by the high temperature of compressed air and this situation makes the operation unstable, an object of the present subject matter is to address this problem. A water injected scroll air compressor is provided with: an air end of the scroll air compressor; a driving unit that generates driving force for the air end; a compressing path from a suction port to a discharge port; a portion to inject water into the compressing path; a discharge piping of air discharged from the air end; a tank provided on a path of the discharge piping for storing water separated from the compressed air; and a cooler that is provided on the path of the discharge piping between the tank and the air end and cools the compressed air discharged from the air end.

Abstract: A high reliability water injected scroll air compressor is provided with an orbiting scroll, a fixed scroll corresponding to the orbiting scroll, a motor that generates driving force for making the orbiting scroll orbit the fixed scroll, a compressing path from a suction port to a discharge port, and a portion for injecting water into the compressing path. The operation is controlled by a switching operation in which water is injected into the compressing path and then no water is injected. Corrosion, failure of activation, and concerns about wrap contact when water is injected into an air end are avoided by switching the operation with water injection and the operation without water injection so as to prevent water from remaining in the air end.

Abstract: Disclosed is a water-injection type scroll air compressor whose pre-stopping operation time for drying can be reduced while enhancing compressor efficiency. The compressor body 1 includes a water supply line 24 for supplying water to a water feeder 23 connected to an air suction line 2. The water supply line 24 is provided with a control valve 27 that can control a flow rate of the water. A controller 28 conducts driving control of the control valve 27 in a 5×10?5 to 40×10?5 range of an injected-water volume ratio (more specifically, a volume ratio between an intake air flow rate and injected-water flow rate in the water feeder 23 of the suction line 2) and at the same time, in an injected-water volume ratio range of the compressor characterized so that an increase rate of overall adiabatic efficiency of the compressor per 1×10?5 increase rate of the injected-water volume ratio stays less than 2% of an original or initial value.

Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: An oil-free scroll compressor prevents wraps from being broken and provides improved reliability. The oil-free scroll compressor includes an orbiting scroll member and fixed scroll members, and has compression channels into which water is injected each formed between the intake port and exhaust port provided in the fixed scroll member. The oil-free scroll compressor includes temperature sensors each of which detects temperature in the compression channel, regulating valves each of which controls ratio of the amount of the water to be injected into the respective compression channels to the total amount of the water to be injected into the compression channels, and controller which controls the opening degrees of the regulating valves such that a difference between the detected temperatures from the compression channels is small.

Abstract: As pressure in a water tank rapidly rises when water inside a compressor is evaporated by the high temperature of compressed air and this situation makes the operation unstable, an object of the present subject matter is to address this problem. A water injected scroll air compressor is provided with: an air end of the scroll air compressor; a driving unit that generates driving force for the air end; a compressing path from a suction port to a discharge port; a portion to inject water into the compressing path; a discharge piping of air discharged from the air end; a tank provided on a path of the discharge piping for storing water separated from the compressed air; and a cooler that is provided on the path of the discharge piping between the tank and the air end and cools the compressed air discharged from the air end.

Abstract: To maintain the functionality as a compact and inexpensive motor-mounted internal gear pump and also offer further inexpensiveness and reliability. The motor-mounted internal gear pump 80 has a pump part 81 including: an inner rotor 1, an outer rotor 2, a pump casing and an internal shaft 5. The pump casing has flat inner surfaces facing both end faces of the inner rotor 1 and the outer rotor 2. The internal shaft 5 includes a bearing 51 which is inserted into an axial hole of the inner rotor 1 and a fitting part 53 extending from both its ends in both axial directions. The pump casing includes two pump casing members 3, 4 as separate members with flat inner surfaces 25, 26 respectively.

Abstract: A high reliability water injected scroll air compressor is provided. In the scroll air compressor provided with: an orbiting scroll; a fixed scroll corresponding the orbiting scroll; a motor that generates driving force for making the orbiting scroll orbit the fixed scroll; a compressing path from a suction port to a discharge port; and a portion for injecting water into the compressing path, the operation is controlled by switching operation in which water is injected into the compressing path and operation in which no water is injected. Corrosion, the failure of activation and a touch to the wrap respectively worried when water is injected into an air end are avoided by switching the operation with water injection and the operation without water injection as described above so as to prevent water from remaining in the air end.

Abstract: Disclosed is a water-injection type scroll air compressor whose pre-stopping operation time for drying can be reduced while enhancing compressor efficiency. The compressor body 1 includes a water supply line 24 for supplying water to a water feeder 23 connected to an air suction line 2. The water supply line 24 is provided with a control valve 27 that can control a flow rate of the water. A controller 28 conducts driving control of the control valve 27 in a 5×10?5 to 40×10?5 range of an injected-water volume ratio (more specifically, a volume ratio between an intake air flow rate and injected-water flow rate in the water feeder 23 of the suction line 2) and at the same time, in an injected-water volume ratio range of the compressor characterized so that an increase rate of overall adiabatic efficiency of the compressor per 1×10?5 increase rate of the injected-water volume ratio stays less than 2% of an original or initial value.

Abstract: A screw compressor rotatably accommodates, within a casing including a suction port and a delivery port, a pair of female and male rotors under the meshed state and compresses gas in the state where a liquid is mixed by pouring the liquid to the gas confined within a working chamber formed with both rotors and the casing. On the wall surface of the casing opposing to the rotor delivery end, a recessed part is provided. The working chamber is communicated with the recessed part immediately before isolating from the delivery port and this communication is maintained until a volume of the working chamber substantially becomes zero. Thereby, the screw compressor can be control increase in power consumption, vibration, and noise.

Abstract: An oil-free scroll compressor prevents wraps from being broken and provides improved reliability. The oil-free scroll compressor includes an orbiting scroll member and fixed scroll members, and has compression channels into which water is injected each formed between the intake port and exhaust port provided in the fixed scroll member. The oil-free scroll compressor includes temperature sensors each of which detects temperature in the compression channel, regulating valves each of which controls ratio of the amount of the water to be injected into the respective compression channels to the total amount of the water to be injected into the compression channels, and controller which controls the opening degrees of the regulating valves such that a difference between the detected temperatures from the compression channels is small.

Abstract: When an oil-flooded screw compressor is started up in a cold environment after a long halt, start-up torque increases due to the increased viscosity of the oil that has long stayed inside the working chambers of the compressor. This has necessitated drive means with a larger capacity than that required for normal operation. An oil-flooded screw compressor according to the invention comprises: a casing; a pair of rotors each having screw-thread-shaped groove and being housed in the casing; an electric motor for rotationally driving the pair of rotors; a control device for controlling the electric motor; an oil feeding mechanism for feeding oil into working chambers formed by being enclosed by the casing and the pair of rotors in which teeth thereof are meshed to each other; and an oil separating mechanism for separating the oil from compressed gas discharged from the working chambers.

Abstract: A motor-integrated internal gear pump that is inexpensive and highly reliable while maintaining characteristics of small size and inexpensive functions. The motor-integrated internal gear pump (80) has a pump section (81) with an inner rotor (1), an outer rotor (2), a pump casing, and an inner shaft (5). The pump casing has flat inner surfaces facing both end surfaces of each of the inner rotor (1) and the outer rotor (2). The inner shaft (5) has a bearing section (51) inserted into a shaft hole of the inner rotor (1) and fitting sections extending axially outward from both end surfaces of the inner shaft (51). The pump casing is constructed from two pump casing members (3, 4) where the flat inner surfaces (25, 26) are formed as separate members.

Abstract: A motor-mounted internal gear pump 80 includes: a pump part 81 which sucks and discharges hydraulic fluid; and a motor part 82 which drives the pump 81. The pump part 81 includes: an inner rotor 1 with teeth on its outer surface; an outer rotor 2 with teeth on its inner surface to mesh with the teeth of the inner rotor; and pump casings 3, 4 which house the inner rotor 1 and the outer rotor 2. The motor part 82 includes a rotator 11 and a stator 12 which rotates the rotator 11. A common member 112 of permanent magnet material as resin containing magnetic powder serves as the rotator 11 and the outer rotor 2. This structure assures further inexpensiveness and reliability while maintaining compactness and inexpensiveness in functions.