US 5,183,395 AGranted

Compressor slide valve control

AssigneeVilter Manufacturing Corporation

InventorLuc Langouet

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Abstract

A variable capacity rotary screw compressor having a rotor housing including a bore, an inlet, an outlet, a slide valve recess and rotors. Passive and active slide valves are mounted in the recess. Individual passive and active slide valve balancing units are connected to the passive and active slide valves respectively. A prime mover is connected to selectively regulate the position of the active slide valve. A first conduit is connected between the housing inlet and the passive and active slide valve balancing units and includes a first valve operable to either open or close the first conduit. A second conduit is connected in fluid communication between the outlet and the passive and active slide valve balancing units and includes a second valve operable to either open or close the second conduit. A first sensor provides a first signal proportional to suction pressure. A second sensor provides a second signal proportional to discharge pressure. A third sensor provides a third signal proportional to the position of the active slide. A control receives the first, second and third signals and provides: first and second control outputs to open either the first or the second valve to balance the passive and active slide valves with either suction or discharge pressure; and a third control output connected to the prime mover for regulating the position of the active slide valve.

Claims10

Dependent claims

A variable capacity rotary screw compressor comprising:

a rotor housing including a bore means having an inlet at a suction pressure, an outlet at a discharge pressure and a slide valve recess in fluid communication between said bore and said inlet;
a rotor means mounted for rotation in said bore means to compress a fluid received from said inlet and discharge said fluid at a higher pressure into said outlet;
a passive slide valve means and an active slide valve means mounted for movement in said recess either to a sealing position to prevent fluid communication through said recess or to positions defining a variable volume opening placing said bore means and inlet in fluid communication;
a passive slide valve balancing means connected to said passive slide valve means and including a first pressure activated means having inner and outer pressure responsive portions, said inner portion permanently connected in open communication with said suction pressure;
an active slide valve balancing means connected to said active slide valve means including a second pressure actuated means having inner and outer pressure responsive portions, said inner portion permanently connected in open communication with said discharge pressure;
a prime mover connected to selectively regulate the position of said active slide valve means;
and
a control means operative to connect both of said outer portions of said first and second pressure activated means in fluid communication with either said suction pressure or said discharge pressure to counterbalance axial thrust on said active slide means with the use of either suction or discharge pressure and to activate said prime mover to regulate the position of said active slide valve means.

5 more elements

A variable capacity rotary screw compressor comprising:

a rotor housing including a bore means, an inlet at a suction pressure, a discharge bore having an outlet at a discharge pressure, an outer passive slide valve chamber, an inner passive slide valve chamber, an outer active slide valve chamber and a slide valve recess in fluid communication between said bore means and said inlet;
a rotor means mounted for rotation in said bore means to compress a fluid received from said inlet and discharge said fluid at a higher pressure through said outlet;
a passive slide valve means and an active slide means mounted in said recess for movement either to a sealing position to prevent fluid communication through said recess or to positions defining a variable volume opening placing said bore means and inlet in fluid communication;
a prime mover connected to selectively regulate the position of said active slide valve means;
a passive slide valve balancing means mounted between said outer and inner passive slide valve chambers and connected to said passive slide valve means;
an active slide valve balancing means mounted between said discharge bore and said outer active slide valve chamber and connected to said active slide valve;
duct means connecting said inner passive slide valve chamber in permanently open fluid communication with said suction pressure;
a conduit means including valve means for selectively connecting said outer passive and outer active slide valve chambers in fluid communication with either said suction or said discharge pressure;
and
a control means operatively connected to said valve means to place both said outer passive slide valve chamber and said outer active slide valve chamber in fluid communication with either said suction pressure or said discharge pressure to counterbalance axial thrust imposed on said active slide valve with the use of either the suction or discharge pressure and to actuate said prime mover to regulate the position of said active slide valve in said recess.

7 more elements

Dependencies are inferred from the claim text.