Ejector and method

Abstract

In an aspect of the invention there is provided fluid pump apparatus comprising a plurality of ejectors, the apparatus having at least one motive fluid inlet arranged to supply motive fluid to the apparatus, at least one suction fluid inlet arranged to supply suction fluid to the apparatus and a common discharge outlet from which motive fluid and suction fluid that have passed through the ejectors may be expelled from the apparatus, each ejector having a respective injector portion and a respective diffuser portion, the injector portion being arranged to inject motive fluid from at least one said at least one motive fluid inlet into the diffuser portion thereby to draw suction fluid into the diffuser portion from at least one said at least one suction fluid inlet, the diffuser portion having a Venturi portion, each ejector having a respective flow stabilisation portion downstream of the Venturi portion thereof, the flow stabilisation portion being arranged to stabilise a flow of motive fluid and suction fluid therethrough before the respective flows of fluid through each ejector meet downstream of the ejectors, wherein the flow stabilisation portion comprises a flow stabilisation conduit of substantially constant diameter and a length substantially equal to at least the diameter thereof.

1 . Fluid pump apparatus comprising a plurality of ejectors, the apparatus having at least one motive fluid inlet arranged to supply motive fluid to the apparatus, at least one suction fluid inlet arranged to supply suction fluid to the apparatus and a common discharge outlet from which motive fluid and suction fluid that have passed through the ejectors may be expelled from the apparatus,
 each ejector having a respective injector portion and a respective diffuser portion, the injector portion being arranged to inject motive fluid from at least one said at least one motive fluid inlet into the diffuser portion thereby to draw suction fluid into the diffuser portion from at least one said at least one suction fluid inlet, the diffuser portion having a Venturi portion, each ejector having a respective flow stabilization portion downstream of the Venturi portion thereof, the flow stabilization portion being arranged to stabilize a flow of motive fluid and suction fluid therethrough before the respective flows of fluid through each ejector meet downstream of the ejectors,   wherein the flow stabilization portion comprises a flow stabilization conduit of substantially constant diameter and a length substantially equal to at least the diameter thereof.   
     
     
         2 . Apparatus as claimed in  claim 1  wherein the plurality of ejectors are arranged in a substantially parallel configuration. 
     
     
         3 . Apparatus as claimed in  claim 1  wherein the injector portion of at least one of the ejectors comprises a plurality of injectors. 
     
     
         4 . Apparatus as claimed in  claim 1  having a common motive fluid inlet arranged to supply motive fluid to each of the plurality of ejectors. 
     
     
         5 . Apparatus as claimed in  claim 1  having a separate motive fluid inlet for each ejector whereby a flow of motive fluid to the nozzle portion of one ejector may be prevented from mixing with a flow of motive fluid to the nozzle portion of another ejector. 
     
     
         6 . Apparatus as claimed in  claim 1  operable to prevent a flow of fluid through the injector portion of one or more of the plurality of ejectors. 
     
     
         7 . (canceled) 
     
     
         8 . Apparatus as claimed in  claim 1  operable to prevent a flow of fluid through the diffuser portion of one or more of the plurality of ejectors. 
     
     
         9 . Apparatus as claimed in  claim 1  operable to allow a reverse flow of fluid through the diffuser portion of one or more of the plurality of ejectors. 
     
     
         10 . (canceled) 
     
     
         11 . Apparatus as claimed in  claim 1  wherein one of the plurality of ejectors has a portion having a size different from the corresponding portion of another of the ejectors. 
     
     
         12 - 13 . (canceled) 
     
     
         14 . Apparatus as claimed in  claim 11  wherein said portion is one selected from amongst the injector portion, the diffuser portion, the Venturi portion and the flow stabilization portion. 
     
     
         15 . Apparatus as claimed in  claim 11  wherein the ejectors are arranged to allow different respective flow rates of fluid therethrough. 
     
     
         16 . Apparatus as claimed in  claim 15  wherein the Venturi portions of the plurality of ejectors have different respective diameters. 
     
     
         17 . Apparatus as claimed in  claim 16  comprising four ejectors, and wherein the respective Venturi portions of the four ejectors are arranged to allow a flow rate of fluid therethrough in the ratio 1:2:3:4. 
     
     
         18 . Apparatus as claimed in  claim 1  coupled to a separation system operable to separate liquid from solids. 
     
     
         19 . (canceled) 
     
     
         20 . Apparatus as claimed in  claim 18  wherein the separation system comprises a cyclonic separator or wherein the separation system comprises an axial flow cyclonic separator. 
     
     
         21 . (canceled) 
     
     
         22 . Apparatus as claimed in  claim 1  installed in an underwater system. 
     
     
         23 . Apparatus as claimed in  claim 1  located in an underwater system and arranged to pump a fluid in the underwater system. 
     
     
         24 . Apparatus as claimed in  claim 1  wherein the flow stabilization conduit has substantially the same diameter as a downstream end of the Venturi portion. 
     
     
         25 . Apparatus as claimed in  claim 1  wherein the flow stabilization conduit has a length substantially equal to from one to two times or from two to three times the diameter thereof. 
     
     
         26 . Apparatus as claimed in  claim 1  wherein the flow stabilization conduit has a length substantially equal to one selected from amongst four times, five times, six times, seven times, eight times, nine times, ten times, fifteen times, twenty times, fifty times and one hundred times the diameter thereof. 
     
     
         27 . Apparatus as claimed in  claim 1  wherein the flow stabilization conduit has a length L to diameter D ratio R=L/D where R is given substantially by one selected from amongst 3≦R<4, 4≦R<5, 5≦R<6, 6≦R<7, 7≦R<8, 8≦R<9, 9≦R<10, 11≦R<15, 15≦R<20, 20≦R<50, 50≦R<100, R≧100. 
     
     
         28 . Apparatus as claimed in  claim 1  further comprising a manifold portion between the ejectors and the discharge outlet, the manifold portion comprising a conduit arranged to receive fluid flowing out from the respective flow stabilization portions of the ejectors and to direct the fluid to the discharge outlet. 
     
     
         29 . Apparatus as claimed in  claim 1  in combination with a bend conduit being a conduit having a bend portion wherein the conduit bends through an angle θ where θ is nonzero, the bend portion being provided downstream of the common discharge outlet wherein fluid flowing through the plurality of ejectors is directed to flow through the bend conduit. 
     
     
         30 . Apparatus as claimed in  claim 29  wherein the bend conduit is arranged wherein  0  takes a value given by one selected from amongst 30°≦θ60°, 60°≦θ<90°, 90°≦θ<120°, 120°≦θ<150° and 150°≦θ≦180°. 
     
     
         31 . Apparatus as claimed in  claim 29  wherein θ takes a value of one selected from amongst substantially 45°, substantially 90° and substantially 180°. 
     
     
         32 . A method of pumping a fluid comprising the steps of:
 providing a flow of motive fluid to each of a plurality of ejectors thereby to draw suction fluid through each ejector and expel discharge fluid drawn through the ejectors through a common discharge outlet, each ejector having a respective injector portion and a respective diffuser portion;   injecting motive fluid into the diffuser portion thereby to draw the suction fluid into the diffuser portion, the diffuser portion having a Venturi portion, each ejector having a respective flow stabilization portion downstream of the Venturi portion thereof; and   stabilizing the flow of fluid from the diffuser portion as it passes through the flow stabilization portion which includes a conduit having a substantially constant diameter and a length substantially equal to at least the diameter thereof, before respective fluid flows through each ejector meet downstream of the ejectors.   
     
     
         33 - 34 . (canceled)