Contra-rotating fan arrangement and fan drive system for evaporative cooling equipment

Abstract

A counter-rotating fan system for evaporative cooling equipment. The system can include a first axial fan disposed in an air conduit of an evaporative equipment unit, a second axial fan disposed in the air conduit and arranged coaxially with the first fan, a transmission for driving the first axial fan and the second axial fan, and a motor for driving the transmission, wherein the direction of rotation of the first axial fan is opposite to the direction of rotation of the second axial fan.

1 . A counter-rotating fan system for evaporative cooling equipment, comprising:
 a first axial fan disposed in an air-restricted conduit of an evaporative equipment unit;   a second axial fan disposed in the air-restricted conduit and arranged coaxially with the first fan, walls of the conduit closely enclosing the tips of the first axial fan and the second axial fan;   a transmission for driving the first axial fan and the second axial fan; and   a motor for driving the transmission, the motor and transmission driving the first axial fan and the second axial fan at at least one speed configured to (i) maintain airflow at a minimum value necessary to maintain an endothermic process of evaporation, and (ii) maintain static pressure at a minimum value necessary to maintain the endothermic process of evaporation;   wherein the direction of rotation of the first axial fan is opposite to the direction of rotation of the second axial fan.   
     
     
         2 . The fan system of  claim 1 , wherein the speed of rotation of the first axial fan is different from the speed of rotation of the second axial fan. 
     
     
         3 . The fan system of  claim 1 , further comprising:
 a first output shaft coupled to the first axial fan and driven by the transmission in a first direction; and   a second output shaft coupled to the second axial fan and driven by the transmission in a direction opposite to the first direction.   
     
     
         4 . The fan system of  claim 3 , wherein the first output shaft is rotatably disposed within the second output shaft. 
     
     
         5 . (canceled) 
     
     
         6 . The fan system of  claim 1 , further comprising:
 a first output shaft coupled to the first axial fan and driven by the transmission in a first direction; and   a hub operatively coupled to the first output shaft and the second axial fan, the hub adapted to drive the second axial fan in a direction opposite to the first direction.   
     
     
         7 . The fan system of  claim 1 , wherein an output shaft of the motor is coupled to an input shaft of the transmission via a belt drive. 
     
     
         8 . The fan system of  claim 1 , wherein an output shaft of the motor is directly coupled to an input shaft of the transmission. 
     
     
         9 . The fan system of  claim 1 , wherein an output shaft of the motor is coupled to an input shaft of the transmission via an angle gearing arrangement. 
     
     
         10 . The fan system of  claim 1 , wherein the air conduit is an air discharge conduit. 
     
     
         11 . The fan system of  claim 1 , wherein the air conduit is an air intake conduit. 
     
     
         12 . An evaporative cooling equipment unit, comprising:
 an enclosure;   at least one air conduit;   a first axial fan disposed in the at least one air conduit; and   a second axial fan disposed in the at least one air conduit and arranged coaxially with the first fan;   wherein the direction of rotation of the first axial fan is opposite to the direction of rotation of the second axial fan; and   wherein the speed of rotation of the first axial fan is different than the speed of rotation of the second axial fan.   
     
     
         13 . The evaporative cooling equipment unit of  claim 12 , wherein the at least one air conduit is an air discharge conduit. 
     
     
         14 . The evaporative cooling equipment unit of  claim 12 , wherein the at least one air conduit is an air intake conduit. 
     
     
         15 . The evaporative cooling equipment unit of  claim 12 , further comprising:
 a transmission for driving the first axial fan and the second axial fan; and   a motor for driving the transmission.   
     
     
         16 . The fan system of  claim 1 , further comprising:
 a first output shaft coupled to the first axial fan and driven by the transmission in a first direction; and   a second output shaft coupled to the second axial fan and driven by the transmission in a direction opposite to the first direction.   
     
     
         17 . The fan system of  claim 16 , wherein the first output shaft is rotatably disposed within the second output shaft. 
     
     
         18 . The fan system of  claim 1 , wherein the transmission is disposed between the first axial fan and the second axial fan. 
     
     
         19 . The fan system of  claim 15 , further comprising:
 a first output shaft coupled to the first axial fan and driven by the transmission in a first direction; and   a hub operatively coupled to the first output shaft and the second axial fan, the hub adapted to drive the second axial fan in a direction opposite to the first direction.   
     
     
         20 . The fan system of  claim 1 , wherein the conduit has an internal width, and wherein at least the first axial fan has a blade width which is no less than about ninety percent of the conduit internal width. 
     
     
         21 . An evaporative cooling equipment counter-rotating fan system, comprising:
 an air-restricted conduit coupled to the evaporative cooling equipment;   a first axial fan an a second axial fan disposed inside the air-restricted conduit and arranged coaxially with respect to each other, walls of the conduit closely enclosing the tips of the first axial fan and the second axial fan;   a transmission for driving the first axial fan and the second axial fan; and   means for driving the transmission to (i) maintain airflow at the minimum value necessary to maintain an endothermic process of evaporation, and (ii)) maintain static pressure at the minimum value necessary to maintain the endothermic process of evaporation, the means for driving rotating of the first axial fan in a direction opposite to the direction of rotation of the second axial fan.