US3910731A — Screw rotor machine with multiple working spaces …

Claim 1

Independent Claim 217 words

Screw rotor machine for an elastic working fluid comprising: a casing enclosing at least two working spaces, each generally comprising two intersecting bores with parallel axes and provided with barrel walls, with low pressure and high pressure end walls perpendicular to said axes, and with low pressure and high pressure ports disposed in said walls; a pair of intermeshing rotors respectively disposed in each working space, each rotor provided with helical lands and intervening grooves having a wrap angle of less than 360*, each pair of intermeshing rotors comprising one rotor of male rotor type and one rotor of female rotor type; and a transmission chamber housing a power transmission, one rotor of each stage being further interconnected by said power transmission disposed in said separate transmission chamber; the improvement wherein the casing comprises: a common barrel member enclosing at least the major portions of the working spaces in parallel side by side; and an end plate member directly connected to said barrel member, said end plate member having: one common plane surface constituting an end wall of each of said working spaces; means for carrying bearings for all the rotors; means for enclosing said transmission chamber; and depressions in said common plane surface which form at least portions of a communication channel between said working spaces.

Claim 2

Dependent Claim 217 words

Screw rotor machine for an elastic working fluid comprising: a casing enclosing at least two working spaces, each generally comprising two intersecting bores with parallel axes and provided with barrel walls, with low pressure and high pressure end walls perpendicular to said axes, and with low pressure and high pressure ports disposed in said walls; a pair of intermeshing rotors respectively disposed in each working space, each rotor provided with helical lands and intervening grooves having a wrap angle of less than 360*, each pair of intermeshing rotors comprising one rotor of male rotor type and one rotor of female rotor type; and a transmission chamber housing a power transmission, one rotor of each stage being further interconnected by said power transmission disposed in said separate transmission chamber; the improvement wherein the casing comprises: a common barrel member enclosing at least the major portions of the working spaces in parallel side by side; and an end plate member directly connected to said barrel member, said end plate member having: one common plane surface constituting an end wall of each of said working spaces; means for carrying bearings for all the rotors; means for enclosing said transmission chamber; and depressions in said common plane surface which form at least portions of a communication channel between said working spaces.

Claim 3

Dependent Claim 47 words

Machine as defined in claim 1, in which said end plate member is provided with an internal communication channel connecting two working spaces in series through the high pressure port of the low pressure stage and through the low pressure port of the high pressure stage, respectively.

Claim 4

Dependent Claim 22 words

Machine as defined in claim 2, in which means are provided for liquid injection into at least one of said working spaces.

Claim 5

Dependent Claim 18 words

Machine as defined in claim 3, in which said transmission chamber forms a part of said communication channel.

Claim 6

Dependent Claim 36 words

Machine as defined in claim 4, in which an axially slidable valve is so provided in the barrel walls of the low pressure stage that in fully open position said valve extends into said transmission chamber.

Claim 7

Dependent Claim 37 words

Machine as defined in claim 3, in which said transmission is provided to give the male rotor of the low pressure stage a higher tip speed than that of the male rotor of the high pressure stage.

Claim 8

Dependent Claim 38 words

Machine as defined in claim 6, in which the ratio between the tip speeds of the male rotors of the low pressure stage and of the high pressure stage, respectively, lies within the range 1.5: 1 to 3:1.

Claim 9

Dependent Claim 33 words

Machine as defined in claim 7, in which the ratio between the tip speeds of the male rotors of the low pressure stage and of the high pressure stage, respectively, is about 2.2:1.

Claim 10

Dependent Claim 60 words

Machine as defined in claim 7, in which the tip speed of the male rotor of the high pressure stage is defined by the formula s c . P2/P1 where s is the tip speed in m/s, c is a constant within the range 1 to 1.5, preferably about 1.25, and P2/P1 is the total pressure ratio of the machine.

Claim 11

Dependent Claim 21 words

Machine as defined in claim 1, in which the length of the rotors are the same in the different working spaces.

Claim 12

Dependent Claim 32 words

Machine as defined in claim 10 acting as a compressor, in which the male rotor in one working space has the diameter as that of the male rotor in another working space.

Claim 13

Dependent Claim 27 words

Machine as defined in claim 1, in which the power shaft of the transmission is coaxial with the axis of one male rotor and rigidly connected thereto.

Claim 14

Dependent Claim 36 words

Machine as defined in claim 12, in which the male rotors carry directly intermeshing gears of helical type having helix angles providing a distribution of the thrust forces between the thrust bearings for said male rotors.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-10-06	1979-04-07	1979-10-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-10-06	1983-04-07	1983-10-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-10-06	1987-04-07	1987-10-07	$7700.00	Window Closed / Lapsed

Screw rotor machine with multiple working spaces interconnected via communication channel in common end plate

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