A pump and a method of pumping a gas

Abstract

A pump includes a pump housing element and a further element; one of the pump housing and the further element comprising a helical protrusion extending towards the other element, the other element comprising at least one liquid opening. The helical protrusion, pump housing and further element form a path from a gas inlet to a gas outlet. The helical protrusion has an axial cross section that is wider at its attached end than it is at its free end. The pump housing and further element are mounted rotatably with respect to each other; and the at least one liquid opening is configured such that liquid output from the at least one liquid opening forms a liquid blade, the liquid blade being operable to drive gas along the path from the gas inlet to the gas outlet on rotation of one of the elements.

1 . A pump for pumping a gas, said pump comprising:
 a pump housing element and a further element;   one of said pump housing and said further element comprising a protrusion extending towards the other element, said other element comprising at least one liquid opening;   said protrusion, pump housing and further element forming a path from a gas inlet to a gas outlet; wherein   said further element is concentrically mounted within a bore of said pump housing and said pump housing and further element are mounted rotatably with respect to each other; and   said protrusion comprises a helix, a cross section through an axial plane of said helix varying such that said helix is narrower at a point towards said other element and wider at an intersection of said protrusion with said one of said pump housing and said further element from which said protrusion extends;   said at least one liquid opening is configured such that liquid output from said at least one liquid opening forms a liquid blade, said liquid blade being operable to drive gas along said path from said gas inlet to said gas outlet on rotation of one of said elements.   
     
     
         2 . The pump according to  claim 1 , wherein said protrusion is at least twice as wide at a point 10% along the protrusion from the element from which it extends as it is at a point 95% along the protrusion and preferably more than four times as wide. 
     
     
         3 . The pump according to  claim 1 , wherein an upper surface of said at least one protrusion has a substantially parabolic form. 
     
     
         4 . The pump according to  claim 1 , wherein said at least one protrusion extends from said pump housing element and has a cross section through a radial plane such that said protrusion does not mask said pump housing element from one or both of:
 (i) a water blade extending tangentially out from said further element; and   (ii) a water blade extending at right angles from said further element.   
     
     
         5 . (canceled) 
     
     
         6 . The pump according to  claim 1 , wherein a lower surface of said at least one protrusion is flat. 
     
     
         7 . The pump according to  claim 1 , wherein a trailing edge with respect to the direction of rotation of said cross section of said protrusion in said radial plane is at an acute angle with respect to a tangent to said pump housing wall that is between a maximum angle where said trailing edge is parallel to said tangent of said further element and up to 15% less than said maximum angle
 wherein said trailing edge of said protrusion in said radial plane is optionally angled such that said surface is substantially parallel to a tangent of said further element.   
     
     
         8 . (canceled) 
     
     
         9 . The pump according to  claim 1 , wherein a leading edge with respect to the direction of rotation of said cross section of said protrusion in said radial plane lies between a curved line curved in the direction of rotation and with a radius of curvature equal to half a distance between said pump housing element and said further element and a line extending away from said trailing edge and parallel to a tangent of said further element
 wherein a leading edge with respect to the direction of rotation of said cross section of said protrusion in said radial plane optionally comprises a surface substantially perpendicular to a tangent to said further element.   
     
     
         10 - 11 . (canceled) 
     
     
         12 . The pump according to  claim 1 , wherein an axial cross section of said protrusion has a substantially parabolic form. 
     
     
         13 . The pump according to  claim 1 , wherein said protrusion has a cross section through a radial plane comprising a segment of a circular cross section of said pump housing element
 wherein said pump housing is optionally mounted to be stationary and said further element is mounted to rotate.   
     
     
         14 . (canceled) 
     
     
         15 . The pump according to  claim 1 , wherein said at least one liquid opening is formed on a surface of said element that is mounted to rotate. 
     
     
         16 . The pump according to  claim 1 , wherein a cross section of said path formed by said protrusion, pump housing and further element decreases from said gas inlet to said gas outlet. 
     
     
         17 . The pump according to  claim 1 , wherein said at least one liquid opening comprises at least one liquid opening extending along at least a portion of a length of one of said pump housing or further element
 wherein said at least one liquid opening is optionally arranged along a longitudinal direction running substantially parallel to an axis of said elements.   
     
     
         18 . (canceled) 
     
     
         19 . The pump according to  claim 1 , wherein said at least one liquid opening is arranged in the form of a helix extending around a surface of said pump housing or further element. 
     
     
         20 . The pump according to  claim 1 , wherein an angle of said helix changes from said gas inlet towards said gas outlet such that a pitch of said helix reduces towards said gas outlet. 
     
     
         21 . The pump according to  claim 1 , further comprising a liquid reservoir, said further element being rotatably mounted and comprising a hollow body having an opening at a lower end extending into said liquid reservoir, an internal diameter of said hollow rotor increasing from said lower end. 
     
     
         22 . The pump according to  claim 1  comprising a plurality of liquid openings
 wherein said plurality of liquid openings optionally provide a plurality of streams of liquid which form a plurality of liquid blades between said pump housing element and said further element. 
 
     
     
         23 . (canceled) 
     
     
         24 . The pump according to  claim 22 , wherein at least one set of said plurality of liquid outlets are arranged adjacent to each other and streams output from said at least one set of said plurality of liquid outlets form a single liquid blade. 
     
     
         25 . The pump according to  claim 1  wherein said pump comprises a vacuum pump. 
     
     
         26 . The wet scrubber for reducing pollutants pumped from an abatement system, said wet scrubber comprising a pump according  claim 1 . 
     
     
         27 . A method of pumping a gas, said method comprising:
 outputting liquid from at least one liquid opening on one of a pump housing element or a further element, the other of said pump housing and said further element comprising a protrusion, said protrusion, pump housing and further element forming a path from a gas inlet to a gas outlet; wherein   said protrusion comprises a helix, a cross section through an axial plane of said helix varying such that said helix is narrower at a point towards said other element and wider at an intersection of said protrusion with said one of said pump housing and said further element from which said protrusion extends;   rotating one of said pump housing element or said further element such that liquid output from said at least one liquid opening forms a liquid blade and drives gas along said path from said gas inlet to said gas outlet on rotation of one of said elements.