Screw compressor and method of manufacturing rotor for the same
AssigneeHitachi, Ltd.
InventorsTakeshi Hida, Masayuki Urashin, Shigekazu Nozawa, Hiroki Ohsumimoto, Hirotaka Kameya, Atsushi Watanabe
Life of this patent
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Abstract
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.
Claims10
A screw compressor comprising:
- at least one pair of male and female rotors engaging with each other;
- a bearing member supporting the rotors;
- a motor for driving the rotors;
- and
- a casing member accommodating the rotors, the bearing member and the motor, wherein
- the motor drives the female rotor, so that the male rotor is driven by the female rotor, and
- at least one of the male and female rotors is composed of a member which is made of cast iron and is subjected to surface hardening treatment.
A screw compressor comprising:
- at least one pair of male and female rotors engaging with each other;
- a bearing member supporting the rotors;
- a motor for driving the rotors;
- and
- a casing member accommodating the rotors, the bearing member and the motor, wherein
- the motor drives the female rotor, so that the male rotor is driven by the female rotor, and
- at least one of said male and female rotors is composed of a member which is made of cast iron and is subjected to heat treatment including quenching.
A screw compressor comprising:
- a male rotor;
- a female rotor engaging with the male rotor, the number of the teeth of the female rotor being larger than that of the male rotor;
- a bearing member supporting the male and female rotors;
- a motor for driving the rotors;
- and
- a casing member accommodating the male and female rotors, the bearing member and the motor, wherein
- the motor drives the female rotor, so that the male rotor is driven by the female rotor, and
- the male and female rotors are composed of a member which is made of cast iron and is subjected to quenching treatment in a liquid of a temperature of 200 to 450° C.
A method of manufacturing a rotor of a screw compressor in which a female rotor having a larger number of teeth than a male rotor is driven by a motor and the male rotor is driven by the female rotor, the method including the steps of:
- making the rotor of ductile iron;
- heating the rotor;
- subjecting the rotor to quenching treatment in a salt bath of a temperature of 200 to 450° C.;
- and
- then holding the rotor in the salt bath at a temperature of 200 to 450° C. for 5 to 240 minutes.
Dependencies are inferred from the claim text.