fig1 represents a perspective view of one type of rotatable bowl ( 1 ) with a central hub ( 2 ) and elliptical opening 50 . the mixer has 4 nozzles ( 3 to 6 ) fed by a common conduit ( 7 ). fig3 illustrates an embodiment in which the bowl has no center part , and a fifth nozzle 6 ′ is added to wet the central part of the bowl at injection point 13 ′ ( fig4 ). the nozzles ( 3 to 6 ) are diametrically opposite each other and spaced apart by circa 50 mm , along the large axis of an ellipse , and circa 36 mm along its small axis , such that the nozzles can traverse the powder and wet the bottom of the bowl at four equidistant points located at the same distance from the internal and external edges . as illustrated in fig2 the hub has an elliptical shape defined by a large axis greater than a small axis , the large and small axes of the hub being aligned with the large and small axes of the opening . the first and third nozzles define a first line through the axis of rotation , and the second and fourth nozzles define a second line through the axis of rotation , orthogonal to the first line , as illustrated in fig1 and 2 . the nozzles ( 3 to 6 ) are made out of small stainless steel tubes of variable length , but preferably ca . 20 mm in length . their inside diameter is also variable but the diameter of 13 / 10 mm yields excellent results . the water pressure should be between 0 and 8 bar , preferably between 2 and 4 bar , so as to be able to penetrate the powder and reach the bottom of the bowl . in fact , the speed and quality of the mixing is essentially dependent on the wetting of the bottom of the bowl . the stability of the injection is ensured by a pressure valve set between 0 and 8 bar , preferably between 2 and 4 bar . the injection of water must be performed in a continuous manner ; pumps providing intermittent flow are not suitable because even when two are placed in phase opposition there is always a splashing phenomenon linked to the intermittent flow which sprays powder in the air and soils the machine , especially the nozzles . the amount of water injected into each bowl is selected in advance on the basis of the number of doses ; it is entered into the memory by the microprocessor which retains the same number of doses until it is changed . calibration is implemented when the machine is installed at a given site . the installed software allows upward or downward adjustment of the number of ml per dose ; this change can be for one specific use or entered in the memory . fig2 shows a plan view of the bowl ( 1 ) after injection of the water . the surface of the powder exhibits injection points ( 10 to 13 ). in a preferred embodiment of the present system , the mixer comprises a calibration system controlled by the microprocessor based on the control of the injection time so as to adapt to the water distribution networks ; it includes autonomous systems with pressure . the invention has been described above as a nonlimitative example . it is obvious that an expert in the art could implement variants of implementation without , however , going beyond the scope of the invention .
a mixer for alginate has a rotatable bowl and one or more nozzles positioned above the opening of the rotatable bowl for injecting water into the bowl . by controlling the injection of water at appropriate locations and at appropriate strengths , desired mixing of the alginate can be achieved .