Pump for conveying a highly viscous fluid

Abstract

A pump for conveying a highly viscous fluid includes a casing with at least a first inlet and an outlet for the fluid, an impeller for conveying the fluid from the inlet to the outlet. The impeller is arranged on a rotatable shaft for rotation around an axial direction, and includes a front shroud facing the first inlet of the pump. The casing includes a stationary impeller opening for receiving the front shroud of the impeller and having a diameter. The front shroud and the stationary impeller opening form a gap having a length in the axial direction, the ratio of the length of the gap and the diameter of the impeller opening is at most 0.092.

1 . A pump for conveying a highly viscous fluid,. comprising:
 a casing with at least a first inlet and an outlet for the fluid; and   an impeller configured to convey the fluid from the inlet to the outlet, the impeller being arranged on a rotatable shaft so as to be rotatable in an axial direction, and comprising a front shroud facing the first inlet of the pump, the casing including a stationary impeller opening configured to receive the front shroud of the impeller and having a diameter, the front shroud and the stationary impeller opening forming a gap having a length in the axial direction, and the ratio of the length of the gap and the diameter of the impeller opening being at most 0.092.   
     
     
         2 . A pump in accordance with  claim 1 , wherein the ratio of the length of the gap and the diameter of the impeller opening is at most 0.073. 
     
     
         3 . A pump in accordance with  claim 1 , wherein the ratio of the length of the gap and the diameter of the impeller opening is at most 0.037. 
     
     
         4 . A pump in accordance with  claim 1 , wherein the ratio of the length of the gap and the diameter of the impeller opening is at least 0.0001. 
     
     
         5 . A pump in accordance with  claim 1 , wherein a radial clearance between the front shroud and the impeller opening is at most 0.0045 times the diameter of the impeller opening. 
     
     
         6 . A pump in accordance with  claim 1 , wherein the gap comprises a plurality of lands consecutively arranged with respect to the axial direction and two adjacent lands of the plurality of lands are respectively separated by a groove. 
     
     
         7 . A pump in accordance with  claim 1 , wherein the stationary inlet opening comprises a wear ring delimiting the gap with respect to a radial direction, the wear ring being arranged stationary with respect to the casing. 
     
     
         8 . A pump in accordance with  claim 1 , wherein the impeller comprises a wear ring delimiting the gap with respect to a radial direction, the wear ring being arranged stationary with respect to the impeller. 
     
     
         9 . A pump in accordance with  claim 1 , wherein the pump is a double suction pump, and has a second inlet for the fluid arranged oppositely to the first inlet of the pump, the impeller being a double suction impeller comprising vanes configured to convey the fluid both from the first inlet and from the second inlet to the outlet. 
     
     
         10 . A pump in accordance with  claim 9 , wherein the front shroud is a first front shroud, and stationary impeller opening is a first stationary impeller opening and the impeller comprises a second front shroud facing the second inlet of the pump, and the casing includes a second stationary impeller opening for receiving the second front shroud of the impeller and has a diameter, the second front shroud and the second stationary impeller opening form a gap having a length in the axial direction, and the ratio of the length of the gap formed by the second front shroud and the second stationary impeller opening and the diameter of the second impeller opening is at most 0.092. 
     
     
         11 . A pump in accordance with  claim 10 , wherein the ratio of the length of the gap formed by the second front shroud and the second stationary impeller opening and the diameter of the second impeller opening is at most 0.073. 
     
     
         12 . A pump in accordance with  claim 10 , wherein the ratio of the length of the gap formed by the second front shroud and the second stationary impeller opening and the diameter of the second impeller opening is at most 0.037. 
     
     
         13 . A pump in accordance with  claim 10 , wherein a radial clearance between the second front shroud and the second impeller opening is at most 0.0045 times the diameter of the second impeller opening. 
     
     
         14 . A pump in accordance with  claim 10 , wherein the gap formed by the first front shroud and the first stationary impeller opening and the gap formed by the second front shroud and the second stationary impeller opening are essentially identical. 
     
     
         15 . A method comprising:
 operating the pump in accordance with  claim 1  in the oil and gas industry.   
     
     
         16 . A pump in accordance with  claim 1 , wherein the ratio of the length of the gap and the diameter of the impeller opening is at most 0.055. 
     
     
         17 . A pump in accordance with  claim 1 , wherein the ratio of the length of the gap and the diameter of the impeller opening is at most 0.019. 
     
     
         18 . A pump in accordance with  claim 10 , wherein the ratio of the length of the gap formed by the second front shroud and the second stationary impeller opening and the diameter of the second impeller opening is at most 0.055. 
     
     
         19 . A pump in accordance with  claim 10 , wherein the ratio of the length of the gap formed by the second front shroud and the second stationary impeller opening and the diameter of the second impeller opening is at most 0.019.