Rotating screw machine with discharge plate

A discharge plate for a rotating screw machine, said rotating screw machine comprising:

• a rotor housing defining an internal cavity in which a plurality of rotatable screw rotors are located, and an outlet casing defining a discharge chamber, wherein:
• said discharge plate is configured to define a plurality of pressure balancing ports that each provide a passageway through the discharge plate, and
• said discharge plate further comprises a plurality of valves coupled to a face of the discharge plate, each said valve being moveable between a position where the valve closes one or more of the pressure balancing ports and a position where the valve opens one or more of the pressure balancing ports;
• wherein the pressure balancing ports and valves are arranged so that in response to a pressure difference the valves can open into the discharge chamber to open one or more of said pressure balancing ports when the discharge plate is coupled between the rotor housing and outlet housing of the rotating screw machine and thereby provide one or more passageways between the rotor housing and the discharge chamber that enable pressure balancing to occur between the internal cavity of the rotor housing and the discharge chamber, the discharge plate being configured so that fluid can pass from the rotor housing to the discharge chamber only via one or more of said passageways when compression pockets between the plurality of rotatable screw rotors align with said pressure balancing ports.

A screw machine comprising:

• a rotor housing defining an internal cavity in which a plurality of rotatable screw rotors are located;
• an outlet housing defining a discharge chamber, and a discharge plate provided between the rotor housing and the outlet housing;
• wherein:
• said screw machine is selected from:
• a screw compressor, a helical twin-screw compressor, an internally geared compressor, a twin-screw pump, a twin screw vacuum pump, a twin screw liquid pump, a twin screw pump for a mixture of liquids and solids, an internally geared pump, an internally geared vacuum pump, an internally geared liquid pump, and an internally geared pump for a mixture of liquids and solids;
• said discharge plate is configured to define a plurality of pressure balancing ports that each provide a passageway through the discharge plate;
• said discharge plate further comprises a plurality of valves coupled to a face of the discharge plate, each said valve being moveable between a position where the valve closes one or more of the pressure balancing ports and a position where the valve opens one or more of the pressure balancing ports;
• and
• wherein the pressure balancing ports and valves are arranged so that in response to a pressure difference the valves can open into the discharge chamber to open one or more of said pressure balancing ports when the discharge plate is coupled between the rotor housing and outlet housings of the screw machine and thereby provide one or more passageways between the rotor housing and the discharge chamber that enable pressure balancing to occur between the internal cavity of the rotor housing and the discharge chamber, the discharge plate being configured so that fluid can pass from the rotor housing to the discharge chamber only via one or more of said passageways when compression pockets between the plurality of rotatable screw rotors align with said pressure balancing ports.