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US 6,719,547 B2Granted
Offset thread screw rotor device
AssigneeImperial Research LLC
InventorCharles K. Heizer
Life of this patent
Estimating the term…
Abstract
A screw rotor device has a housing with an inlet port and an outlet port, a male rotor, and a female rotor. The male rotor has a pair of helical threads with a phase-offset aspect, and the female rotor has a corresponding pair of helical grooves. The female rotor counter-rotates with respect to the male rotor and each of the helical grooves respectively intermeshes in phase with each of the helical threads. The phase-offset aspect of the helical threads is formed by a pair of teeth bounding a toothless sector. The arc angle of the toothless sector is a least twice the arc angle that subtends either one of the teeth. The helical grooves have a radially narrowing axial width at the periphery of the female rotor. The male and female rotors may include a buttress thread profile and may be limited in length to a single pitch.
Claims20
A screw rotor device for positive displacement of a working fluid, comprising:
- a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
- a male rotor having at least one phase-offset helical thread, wherein said male rotor is rotatably mounted about a first axis extending between said first end and said second end of said housing, wherein a cross-section of said phase-offset helical thread, in any plane perpendicular to said first axis, comprises a tooth and a toothless sector, said tooth being subtended by a first arc angle with respect to said axis and said sector having a second arc angle proportionally greater than said first arc angle by a phase-offset multiplier, said tooth having a profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing, and wherein said phase-offset multiplier is at least two for any cross-section taken in any said perpendicular plane;
- and
- a female rotor having at least one helical groove, wherein said female rotor is rotatably mounted about a second axis and counter-rotates with respect to said male rotor and has a periphery in close tolerance with said housing, and wherein said helical groove intermeshes with said helical thread.
1 more element
A screw rotor device for positive displacement of a working fluid, comprising:
- a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
- a male rotor having at least one phase-offset helical thread and having a length approximately equal to a single pitch of said helical thread, wherein said male rotor is rotatably mounted about a first axis extending between said first end and said second end of said housing, wherein a cross-section of said phase-offset helical thread, in any plane perpendicular to said first axis, comprises a tooth and a toothless sector, said tooth being subtended by a first arc angle with respect to said axis and said sector having a second arc angle proportionally greater than said first arc angle by a phase-offset multiplier, said tooth having a profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing;
- and
- a female rotor having at least one helical groove and having a length approximately equal to a single pitch of said helical groove, wherein said female rotor is rotatably mounted about a second axis and counter-rotates with respect to said male rotor and has a periphery in close tolerance with said housing, and wherein said helical groove intermeshes with said helical thread.
1 more element
A screw rotor device for positive displacement of a working fluid, comprising:
- a housing having an inlet port at a first end and an outlet port at a second end and a pair of cylindrical bores extending therebetween;
- a male rotor having at least one phase-offset helical thread, wherein said male rotor is rotatably mounted about a first axis extending between said first end and said second end of said housing, wherein a cross-section of said phase-offset helical thread, in any plane perpendicular to said first axis, comprises a tooth and a toothless sector, said tooth being subtended by a first arc angle with respect to said axis and said sector having a second arc angle proportionally greater than said first arc angle by a phase-offset multiplier, said tooth having a profile comprising a minor diameter arc and a tooth segment radially extending to a major diameter arc in close tolerance with said housing, and wherein said helical thread forms a first buttress thread shape in a lengthwise cross-section of said male rotor in a plane extending between said first axis and said second axis, wherein said first buttress thread shape is comprised of a first line extending from said minor diameter to said major diameter and a straight line extending diagonally away from said first line;
- and
- a female rotor having at least one helical groove, wherein said female rotor is rotatably mounted about a second axis and counter-rotates with respect to said male rotor and has a periphery in close tolerance with said housing, and wherein said helical groove intermeshes with said helical thread and forms a second buttress thread shape in a lengthwise cross-section of said female rotor in a plane extending between said first axis and said second axis, wherein said second buttress thread shape corresponds with said first buttress thread shape and is comprised of a second line extending between a minor diameter and a major diameter of said female rotor and a straight diagonal line extending away from said second line, wherein said straight diagonal line is substantially parallel to said straight line of said male rotor.
1 more element
Dependencies are inferred from the claim text.