Patent ID: 8517594

Claim:
A mixing device for manufacturing a cellular cement slurry, comprising: at least one first mixer comprising a cement inlet and a water and foaming agent inlet, said at least one first mixer being a high-shear mixer operated under conditions to prepare a fluid slurry; and at least one second mixer, said at least one second mixer being operated under controlled- shear conditions, wherein the fluid slurry leaves the at least one first mixer through a discharge outlet and is sent to the at least one second mixer, and the fluid slurry is blended with air in the at least one second mixer, wherein the at least one second mixer comprises inlets consisting of an inlet adapted to receive the fluid slurry from the at least one first mixer and at least one air injection means, wherein the at least one first mixer is an inclined disc mixer having an inclined arrangement with the discharge outlet at a highest point to avoid capture of ambient air into the fluid slurry; and wherein the at least one second mixer comprises a tee for receiving the fluid slurry through a pipe and air through another pipe, wherein the air and the fluid slurry are mixed to some extent in the tee before penetrating into the at least one second mixer.