Optimized energy recovery device

Abstract

A Roots-type device can include a housing assembly having a first opening and a second opening in fluid communication with an internal cavity; a pair of identical rotors oppositely arranged within the housing internal cavity, each of the pair of rotors having a longitudinal axis and plurality of lobes, each of the lobes defining an end face extending between a first longitudinal side of the rotor lobe and a second longitudinal side of the rotor lobe; and a recess port defined within the housing assembly and being axially spaced from the end faces of the rotor lobes, the recess port placing the first longitudinal side of one of the rotor lobes in fluid communication with the second longitudinal side of the rotor lobe such that the housing first opening is placed in fluid communication with the housing second opening. The device can also be provided be provided with an inlet nozzle structure in fluid communication with the first opening, the inlet nozzle tapering towards the first opening and being configured such that a nozzle velocity of a working fluid passing through the nozzle is at least equal to the rotor mesh axial lead velocity.

1 . A Roots-type device comprising:
 a) a housing assembly having a first opening and a second opening in fluid communication with an internal cavity;   b) a pair of identical rotors oppositely arranged within the internal cavity, each of the pair of rotors having a longitudinal axis and a plurality of lobes, each of the lobes defining an end face extending between a first longitudinal side of the lobe and a second longitudinal side of the lobe; and   c) a recess port defined within the housing assembly and being axially spaced from the end faces of the lobes, the recess port placing the first longitudinal side of one of the lobes in fluid communication with the second longitudinal side of the lobe such that the first opening is placed in fluid communication with the second opening.   
     
     
         2 . The Roots-type device of  claim 1 , wherein the housing assembly includes a main housing and a bearing plate secured to the main housing, and wherein the recess port is defined within the bearing plate. 
     
     
         3 . The Roots-type device of  claim 1 , wherein the end face of at least one lobe faces the recess port in all rotational angles of the rotors. 
     
     
         4 . The Roots-type device of  claim 1 , wherein each of the pair of rotors has a twist angle that is less than or equal to an ideal twist angle of the rotors defined without the presence of the recess port. 
     
     
         5 . The Roots-type device of  claim 1 , wherein each of the pair of rotors has at least three lobes. 
     
     
         6 . The Roots-type device of  claim 1 , wherein the rotors are located axially between the first opening and the recess port. 
     
     
         7 . The Roots-type device of  claim 1 , wherein the pair of rotors are each supported by rotatable shafts located between the second opening and the recess port. 
     
     
         8 . The Roots-type device of  claim 1 , wherein the pair of rotors are each supported by shafts having longitudinal axes aligned along a first longitudinal plane, wherein a housing outlet is located on a first side of the first longitudinal plane, and wherein the recess port is located on a second side of the first longitudinal plane. 
     
     
         9 . The Roots-type device of  claim 8 , wherein the first opening is orthogonal to longitudinal axes of the rotors. 
     
     
         10 . The Roots-type device of  claim 9 , wherein the second opening is parallel to the longitudinal axes of the rotors. 
     
     
         11 - 39 . (canceled) 
     
     
         40 . The Roots-type device of  claim 1 , further comprising:
 a) an inlet nozzle structure in fluid communication with the first opening, the inlet nozzle structure tapering towards the first opening and being configured such that a nozzle velocity of a working fluid passing through the inlet nozzle structure is at least equal to a rotor mesh axial lead velocity,   
     
     
         41 . A bearing plate for a Roots-type device, the bearing plate comprising:
 a) a main body extending along a longitudinal axis from a first side to a second side;   b) a pair of cavities for supporting bearing and seal assemblies, the cavities extending between the first and second sides of the main body;   c) a primary surface at least partially defining the first side and being orthogonal to the longitudinal axis; and   d) a first recessed area at least partially defining the first side and being axially recessed from the primary surface in a direction towards the second side, the recessed area being configured to provide a leak path for the Roots-type device.   
     
     
         42 . The bearing plate of  claim 41 , wherein the first recessed area is located entirely on a first side of a plane extending centrally through the pair of cavities and parallel to the longitudinal axis. 
     
     
         43 . The bearing plate of  claim 41 , wherein the first recessed area extends to an outer edge of the main body. 
     
     
         44 . The bearing plate of  claim 42 , wherein the main body includes a second recessed area at least partially defining the first side and being axially recessed from the primary surface in a direction towards the second side, the second recessed area being located entirely on a second side of the plane. 
     
     
         45 . The bearing plate of  claim 41 , wherein the first recessed area has a V-shape. 
     
     
         46 . A Roots-type device comprising:
 a) a housing assembly having a first opening and a second opening in fluid communication with an internal cavity;   b) a pair of identical rotors oppositely arranged within the internal cavity, each of the pair of rotors having a longitudinal axis and a plurality of lobes, wherein the rotors are intermeshed and, when rotating, define a rotor mesh axial lead velocity; and   c) an inlet nozzle structure in fluid communication with the first opening, the inlet nozzle structure tapering towards the first opening and being configured such that a nozzle velocity of a working fluid passing through the inlet nozzle structure is at least equal to the rotor mesh axial lead velocity.   
     
     
         47 . The Roots-type device of  claim 46 , wherein the inlet nozzle structure is oriented generally parallel to the longitudinal axis. 
     
     
         48 . The Roots-type device of  claim 46 , wherein the inlet nozzle structure is oriented at an oblique angle to the longitudinal axis. 
     
     
         49 . The Roots-type device of  claim 46 , wherein a volumetric flow rate through the inlet nozzle structure is increased by at least double.