Abstract: An ice thermal storage type air conditioner includes an outdoor unit 14 equipped with a compressor 12 and an outdoor heat exchanger 13, an indoor unit 17 equipped with an indoor heat exchanger 16 and an expansion valve 18b, and an ice thermal storage tank 5. The ice thermal storage tank is equipped with a heat exchanger exchanger used as a condenser when the accumulated heat is used. The heat exchanger has a pipe-shaped heat transfer tube 1 and a plate-shaped fin 2 installed to the heat transfer tube. The fin is installed vertically, and a plurality of rows of the heat transfer tubes and the fins are arranged.

Abstract: An ice thermal storage type air-conditioner and an ice thermal storage tank, in which unused portions in the ice thermal storage tank is reduced to enhance an ice filling rate in the ice thermal storage tank or to prevent excessive icing from damaging a heat transfer unit.

Abstract: A screw-type rotary fluid machine such as a compressor or a vacuum pump has male and female rotors which rotate within a casing, with or without mutual contact. At least one of the male and female rotors being surface-treated to have a treated surface structure. The treated surface structure is a multi-layered structures composed of a plurality of layers including a non-electrolytic Ni plating layer and at least one covering layer of organic resin. The organic resin may be one or more kinds selected from a group of engineering plastics, so as to improve mechanical strength.

Abstract: A method treating a surface of rotors in a screw-type rotary fluid machine, with the method comprising the steps of: conducting a non-electrolytic Ni plating on the surface of each rotor so as to form a first layer of non-electrolytic Ni plating layer; heating the rotor having the first layer at a temperature not lower than 500.degree. C.; and forming, at least, a second layer of an organic resin so as to cover the first layer.

Abstract: The screw type vacuum pump comprises a pump casing having a suction inlet and a discharge outlet, and a pair of rotors incorporated within the pump casing and meshing with each other to rotate in synchronized manner. The vacuum pump evacuates a reaction vessel, to which process gas is applied, to obtain a negative pressure condition of a predetermined level. Upon operation of the pump, inert gas is introduced into a compression working chamber directly or through a sealing portion disposed adjacent the discharge outlet. The introduced inert gas is adiabatically compressed therein to generate heat to heat the rotors and a casing wall. Further the inert gas effects a reduction of partial pressure of the process gas in the pump. Accordingly, a side reaction product is prevented from accumulating on the rotors and the casing wall.

Abstract: A scroll type pump has a fixed scroll and an orbiting scroll engaging therewith, wherein a curve of a wrap of either of the scrolls is offset inwardly or outwardly relative to a set curve so as to prevent formation of a gap between the wraps due to thermal expansion of the scroll wraps.

Abstract: A screw vacuum pump including a plurality of casings and a pair of rotors defining a plurality of working chambers. The working chambers are constituted by working chambers whose volumes undergo a change as the rotors rotate, and working chambers whose volumes undergo substantially no change as the rotors rotate. The screw vacuum pump is capable of achieving pressure of 10.sup.-1 to 10.sup.-4 Torr or a low or medium vacuum by means of a single pump operating in a single stage.

Abstract: An operation control system of a rotary displacement type vacuum pump capable of reducing a starting torque of the vacuum pump includes a suction regulating valve and a pressure sensor for monitoring suction pressure located in a suction passage of the vacuum pump, an inverter electrically coupled to a variable speed electric motor for driving the vacuum pump and a control unit. The control unit is operative, when the vacuum pump is started, to keep the suction regulating valve in a closed position until the value of suction pressure monitored by the pressure sensor reaches a predetermined upper limit value and to gradually increase the rpm. of the variable speed electric motor. The control unit is further operative to produce a signal for increasing or decreasing the rpm of the variable speed electric motor so as to bring the value of suction pressure monitored by the pressure sensor to the vicinity of a predetermined lower limit value.

Abstract: A rotary fluid machine such as, for example, a screw compressor, a centrifugal compressor, or a pump, is provided with a thrust bearing mounting unit adapted to maintain natural frequencies of bending vibrations of rotors thereof within ranges of permissible values. The axial rigidity of the mounting unit is at least as high as that of the thrust bearings and the radial rigidity thereof is made to be not more than half that thereof. When a radial load is applied to the thrust bearings, the bearing mounting unit is deformed solely substantially in the radial direction and the thrust bearings bear substantially no radial load.

Abstract: A screw compressor including a male rotor and a female rotor forming a pair, a rotor casing enclosing the pair of rotors and cooperating therewith to define a working chamber for compressing gas, a suction port and a discharge port formed in a suction cover and a discharge cover respectively provided to the rotor casing, a slide valve mounted at one part of the rotor casing for axial movement to return gas from the working chamber to the suction side of the compressor, a radial discharge port formed in the slide valve, and an axial discharge port formed in the discharge cover and smaller in size than the radial discharge port. The slide valve is formed therein with at least one gas flow passageway for communicating the working chamber with the discharge port only when the compressor operates in a controlled capacity mode.

Abstract: Screw fluid machines are for use as a compressor for generating high pressure gas, a cooling-medium-compressing compressor for use in a refrigerator or an air conditioner. The fluid machine includes a rotor casing, two side-casings, a pair of screw rotors, and accessories such as silencer, a gas cooler, an oil cooler, and an oil tank. The rotor casing includes an outer wall, an inner wall and interconnecting members or ribs which interconnect the outer wall and the inner wall, with a space being provided between the outer wall and the inner wall. This space is partitioned into two or more spaces by means of the aforesaid interconnecting members. A working chamber or space is provided inwardly of the inner wall and has an inlet port and a discharge port. Both side-casings are secured to the opposite end faces of a rotor casing through the medium of flanges and are provided with a passage adapted to bring two or more spaces thus partitioned, into communication with each other.