Abstract: In a water-supply line for performing water-supply to the rotors and the mechanical seal of a compressor, or in a condensed-water collection line for collecting condensed water of a dryer into the inlet port of the compressor, a water reservoir is provided at a position higher than the water-supply unit of the compressor. Moreover, there are provided a start-time water-supply line and a solenoid valve set up therein. Here, the start-time water-supply line establishes the connection between the lower portion of the water reservoir, and the inlet port of the compressor and the water-supply unit of the mechanical seal.

Abstract: In an oil-cooled air compressor for controlling a temperature of a lubricant by changing a flow rate of a cooling medium supplied to a heat exchanger for the lubricant, for obtaining an energy saving effect by variable control of the flow rate of the cooling medium and preventing securely a condensed water from occurring in a compressor unit even when an exhaust duct is arranged inappropriately, a lubricant flow rate adjustor is arranged to measure a temperature of the lubricant and decreasing a flow rate of the lubricant supplied to the heat exchanger so that the lubricant temperature becomes T1 to satisfy T0>T1?TD when T0 is a control temperature of the lubricant and TD is a condensed water occurrence critical temperature at which a condensed water occurs in the compressor.

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-cooled gas compressor provided with: a compressor body (3); an oil separator (6) that separates out oil from a compressed gas; a gas pipe (8) for sending the compressed gas, from which oil has been separated out by the oil separator, to a user; and an oil pipe (7) for returning, to the compressor, the oil separated out by the oil separator. The following are also provided: an air-cooled heat exchanger (13) for cooling the aforementioned oil; a controllable-speed cooling fan (14) for blowing cooling air at said air-cooled heat exchanger; and a waste-heat-recovery heat exchanger (10), provided upstream of the air-cooled heat exchanger, for recovering heat from the oil flowing through the abovementioned oil pipe. The speed of the cooling fan is controlled so as to bring the temperature of the compressed gas discharged from the compressor body to within a prescribed range.

Abstract: An air compressor 20, for enabling to restart a fan motor when an inverter trip generates within an inverter control of the fan motor, as well as, to continue supplying of compressed air therefrom, comprises: a compressor main body 1; a compressor motor 2 for driving this compressor main body 1; a fan motor 9b for driving a fan 9a; an inverter for controlling the fan motor; and a controller 10 for controlling driving of the compressor motor 2 and driving of the fan motor 9b. The controller 10 conducts such control that the fan motor 9b is brought into a restart waiting condition while continuing operation of the compressor motor 2 when an inverter trip generates, and thereafter to restart the fan motor 9b.

Abstract: The multiblade impeller of the present invention comprises a main plate, a side plate having a suction port at a center thereof, and a large number of blades provided between the main plate and the side plate and extend in the radial direction in an arc form. The main plate and the side plate each have a large number of ridge portions, each extending in the radial direction in an arc form so as to coincide with the shape of the blade extending in the radial direction in an arc form. End portions of the blades are inserted in grooves formed inside the ridge portions of the main plate and the side plate and are fixed to the ridge portions by being bent.

Abstract: An air compressor includes a compressor body, an electric motor, and a gear mechanism that transmits power of the electric motor to the compressor body to prevent intrusion of dust into a casing of the electric motor for improving reliability. In the example in which a gear casing, a load side casing and a seal cover that define the internal space of the gear casing and the internal space of an electric motor main casing, and a non-contact type visco seal provided to a gap in a portion where a rotating shaft of the electric motor penetrates through the load side casing are provided, a communication hole that communicates between a gap from the visco seal toward the electric motor in the load side casing and seal cover and the outside of the air compressor not through the internal space of the electric motor main casing is formed.

Abstract: The multiblade impeller of the present invention comprises a main plate, a side plate having a suction port at a center thereof, and a large number of blades provided between the main plate and the side plate and extend in the radial direction in an arc form. The main plate and the side plate each have a large number of ridge portions, each extending in the radial direction in an arc form so as to coincide with the shape of the blade extending in the radial direction in an arc form. End portions of the blades are inserted in grooves formed inside the ridge portions of the main plate and the side plate and are fixed to the ridge portions by being bent.

Abstract: Provided is a water-cooled air compressor which is capable of restraining lowering of the performance of a plate type compressor for heat-exchanging compressed air from a compressor body, with cooling water due to clogging of gaps between plates in the heat-exchanger by dust or the like, incorporating a first solenoid valve and a second solenoid valve connected respectively in a cooling water supply pipe line and a cooling water discharge pipe line of the heat-exchanger, an air feed pipe line connecting between a compressed air supply pipe line on the outlet side of the heat-exchanger and the cooling water discharge pipe line, a third solenoid valve and a check valve connected in the air feed pipe line, a discharge pipe line connected in a discharge pipe line 18 so as to branch therefrom, a fourth solenoid valve connected in the discharge pipe line, and a control device for controlling opening and closing of the first to fourth solenoid valves.

Abstract: An oil-injection screw compressor includes a blow-off valve disposed on the discharge side of the compressor body and capable of releasing a quantity of air beyond the discharge capacity of the compressor body when operating of the motor at the minimum number of revolutions; a suction non-return valve which, disposed on the suction side of the compressor body, is closed when it is at a stop; and a pressure sensor for detecting the discharge side pressure of the compressor body; and, a controller which, at the time of operation of the motor at the minimum number of revolutions, opens the blow-off valve when the discharge side pressure P detected by the pressure sensor has risen to a prescribed upper limit Pu and closes the blow-off valve when it has fallen to a prescribed control pressure Po.

Abstract: The present invention provides a control method and a control apparatus of an inverter compressor in which when a trip occurs immediately after the inverter is started, retry can be performed in a short period of time with restart being performed in accordance with the detected conditions after the retry waiting times which are different from each other elapse. There are provided two or more kinds of retry waiting times, and the retry waiting time immediately after starting is made shorter than the others.

Abstract: In an oil-cooled screw compressor comprising, a compressor body including a pair of a male rotor and a female rotor, a motor including a stator and a motor rotor connected to one of the male and female rotors, and an oil separator container for gathering the oil from a mixture of the gaseous manner and oil to restrain the oil from proceeding with the compressed gaseous matter after the mixture of the gaseous manner and oil is discharged from the pair of male and female rotors, a rotational axis of the motor rotor and the rotational axis of the one of the male and female rotors are coaxial with respect to each other.

Abstract: Disclosed is a motor control apparatus for controlling a synchronous motor, which includes a receiver section for receiving the value detected by a temperature sensor installed inside the synchronous motor. The synchronous motor is started up with the current fed into it, whose magnitude is changed in accordance with the temperature received by the receiver section at the time of starting up the synchronous motor. In this way, the stable startup of the synchronous motor can be guaranteed and the useful life of the semiconductor elements can also be prolonged.

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: In an oil-cooled screw compressor comprising, a compressor body including a pair of a male rotor and a female rotor, a motor including a stator and a motor rotor connected to one of the male and female rotors, and an oil separator container for gathering the oil from a mixture of the gaseous manner and oil to restrain the oil from proceeding with the compressed gaseous matter after the mixture of the gaseous manner and oil is discharged from the pair of male and female rotors, a rotational axis of the motor rotor and the rotational axis of the one of the male and female rotors are coaxial with respect to each other.

Abstract: An air compressor 20, for enabling to restart a fan motor when an inverter trip generates within an inverter control of the fan motor, as well as, to continue supplying of compressed air therefrom, comprises: a compressor main body 1; a compressor motor 2 for driving this compressor main body 1; a fan motor 9b for driving a fan 9a; an inverter for controlling the fan motor; and a controller 10 for controlling driving of the compressor motor 2 and driving of the fan motor 9b. The controller 10 conducts such control that the fan motor 9b is brought into a restart waiting condition while continuing operation of the compressor motor 2 when an inverter trip generates, and thereafter to restart the fan motor 9b.

Abstract: In an oil-cooled screw compressor comprising, a compressor body including a pair of a male rotor and a female rotor, a motor including a stator and a motor rotor connected to one of the male and female rotors, and an oil separator container for gathering the oil from a mixture of the gaseous manner and oil to restrain the oil from proceeding with the compressed gaseous matter after the mixture of the gaseous manner and oil is discharged from the pair of male and female rotors, a rotational axis of the motor rotor and the rotational axis of the one of the male and female rotors are coaxial with respect to each other.

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: When a compressor is restarted at the time of occurrence of an inverter trip after a retry waiting time which is preliminarily set so as to lower a pressure on a discharge side of a main body of the compressor to a pressure where the main body of the compressor can be restarted elapses, conditions when the inverter trip occurs are detected and restarting is performed in accordance with the detected conditions after the retry waiting times which are different from each other elapse. There are provided two or more kinds of retry waiting times, and the retry waiting time immediately after starting is made shorter than the others. Accordingly, the present invention provides a control method and a control apparatus of an inverter compressor in which when a trip occurs immediately after the inverter is started, retry can be performed in a short time.