Hitachi, Ltd.

Hitachi, Ltd., Trustee, for the Benefit of Hitachi Air Conditioning Systems Co., Ltd.

Takeshi Hida

Shigekazu Nozawa

Masayuki Urashin

Hirotaka Kameya

Atsushi Watanabe

Kenji Tojo

Takao Mizuno

Hideyuki Ueda

Hiroki Ohsumimoto

Hiroki Osumimoto

Noriyuki Yamazaki

Masakazu Aoki

Mutsunori Matsunaga

An oil separator and an oil reservoir are formed integral with a main casing. Also, an opening communicated with the oil reservoir is formed in a part of a lower portion of an oil separation space of the oil separator. Preferably, the opening is formed so that its width is increased as it approaches an outer peripheral side of the oil separation space from a center thereof. Further, a safety valve is installed so that a line connecting between the safety valve and the center of the oil separator is made substantially in parallel to axes of screw rotors.

Screw compressor

A screw compressor of which a female rotor is driven by a motor, and of which a male rotor is driven by the female rotor. The male or female rotor is composed of a member which is made of cast iron and is subjected to surface hardening treatment or heat treatment including quenching. The surface hardening treatment may include sulphonitriding or nitiriding treatment. In the case of subjecting the cast iron to the heat treatment, austemper treatment is applied.

Screw compressor and method of manufacturing rotor for the same

In an oil-mist separator included by a compressor, an inlet passage directs a flow axis of a mixture gas including a mist of lubrication oil and a gas to be taken out of the compressor with a pressurized condition when the mixture gas reaches a chamber, and a discharge port for discharging the gas from the chamber opens in the chamber.

Compressor with oil-mist separator

The screw compressor according to the invention is provided with a main casing having male and female rotors , a discharge casing having a discharge passage for compressed gas discharged from the rotors, and an oil reservoir for accumulating oil separated from the compressed gas. The discharge casing is provided with a cylindrical oil separating space section formed therein so as to communicate with the discharge passage, which discharge passage is connected in a tangential direction of the oil separating space section. Further, a discharge port is provided so as to communicate with the oil separating space section, and a cylindrical member is further provided in the oil separating space section so as to be concentric therewith. The oil separating space section and the oil reservoir are connected to each other through a communication passage having a cross-sectional area smaller than that of the oil separating space section.

Oil separation from discharge gas of a screw compressor is performed with a demister provided in a discharge chamber. For solving unevenness in the speed distribution of the gas in the chamber, at least one auxiliary demister for oil separation is disposed at a local position immediately behind or near the downstream side of an outlet of a discharge passage in a discharge casing so as to be perpendicular to the flow direction of the gas at the outlet. In addition, at least one obstacle plate is disposed on the downstream side of the auxiliary demister.

A screw rotor for use in screw compressors and screw vacuum pumps comprises a pair of rotors including a male rotor and a female rotor. These rotors have helical lobes in an axial direction and mesh with each other to form a compression chamber. Depending upon a lobe configuration of the rotors, suction pressure and discharge pressure, a negative torque for self-rotation as well as a positive torque opposing to rotation due to a compression action is generated on the female rotor in operation. This phenomenon generates when a value obtained by integrating a torque acting on the female rotor over an entire cross section in an axial direction of the rotors becomes negative. When the negative torque is generated, noises due to tooth separating vibration is caused. Then, a lobe profile is defined such that a magnitude of the negative torque is smaller than that of the positive torque in respective cross sections of the female rotor. That is, a relationship between a radius of a point of contact on a leading surface side of the female rotor and a radius of a point of contact on a trailing surface side or curvatures of the rotors are such that the negative torque is not generated on the lobe profile.

Screw fluid machine

A lubricating construction of a scroll compressor includes a seal member provided between an orbiting scroll and a main frame to isolate a back pressure chamber from bearing portions to thereby keep the bearing portions substantially under a discharge pressure, a first oil feed passage extending from a lubricating oil portion under the discharge pressure to a space, disposed adjacent to an end of a crank portion of the crankshaft, through the crankshaft, a second oil feed passage extending from the above space to be opened to sliding portions of end plates of the orbiting and stationary scrolls through the end plate of the orbiting scroll, and communicating with the back pressure chamber, and a third oil feed passage extending from midway the first oil feed passage to be opened to an outer peripheral surface of the crankshaft, and serving to supply a lubricating oil to a main bearing portion by the use of a centrifugal pumping action produced by rotation of the crankshaft. The second oil feed passage has midway a throttle portion of a reduced flow passage area. This lubrication construction supplies the lubricating oil, using the pressure differential and the pumping action in combination.

Scroll compressor

A scroll type compressor having high efficiency and high reliability is obtained by preventing leakage of a compression chamber, increasing air tightness thereof and securing a smooth motion of an orbiting scroll member. A second frame member supported by a first frame member and slightly movable in the axial direction is disposed in the rear of an orbiting scroll member. Force is applied to the rear of the second frame member, and a slight axial movement of the orbiting scroll member is regulated by a fixed scroll member and the second frame member. As a result, both the scroll members are in tight contact or close to each other with a small space, and a smooth movement thereof can be secured, which makes it possible to obtain a scroll type compressor having high efficiency and high reliability.

Growing community of inventors

Shizuoka, Japan

Takeshi Hida