Extrusion of cementitious material with different leveling characteristics

Abstract

A cementitious material delivery system may include a flow divider, a first and second chemical agent, a first and second mixer, and a nozzle. The flow divider may be configured to divide a flow of cementitious material into a first stream and a second stream that is separate from the first stream. The first chemical agent may cure the cementitious material at a first rate. A first mixer may be configured to mix the first chemical agent with the first steam of cementitious material. A second chemical agent may be configured to cure the cementitious material at a second rate. A second mixer separately may be configured to mix the second chemical agent with the second steam of cementitious material. A nozzle may be configured to extrude both mixed streams of cementitious material separate from each other.

1 . A cementitious material delivery system comprising:
 a flow divider configured to divide a flow of cementitious material into a first stream and a second stream that is separate from the first stream;   a chemical agent;   a mixer configured to mix the chemical agent with the first stream of cementitious material to produce a mixed stream of cementitious material, but not to mix the chemical agent with the second stream of cementitious material; and   a nozzle configured to extrude the mixed stream of cementitious material and the second stream of cementitious material separate from the first mixed stream of cementitious material,   wherein the chemical agent is of a composition that results in one of the extrusions from the nozzle being self leveling and the other not being self-leveling.   
     
     
         2 . The cementitious material delivery system of  claim 1  wherein the chemical agent has a composition that causes the first mixed stream of cementitious material to be self-leveling and wherein the second stream of cementitious material is not self leveling. 
     
     
         3 . The cementitious material delivery system of  claim 1  wherein the nozzle:
 has a first, second, and third outlet which are each configured to extrude cementitious material, the second outlet being between the first and the third outlets; and 
 is configured such that:
 the self-leveling extrusion is from the second outlet; and 
 the non-self leveling extrusion is from the first and the third outlets. 
 
 
     
     
         4 . The cementitious material delivery system of  claim 1  further comprising:
 a first metering device in series with the first stream of cementitious material configured to regulate the flow of the first stream of cementitious material; and 
 a second metering device in series with the second stream of cementitious material configured to regulate the flow of the second stream of cementitious material. 
 
     
     
         5 . The cementitious material delivery system of  claim 1  further comprising:
 a second chemical agent; and 
 a second mixer configured to mix the second chemical agent with the second stream of cementitious material, 
 wherein the nozzle is configured to extrude the second stream of cementitious material after it is mixed with the second agent by the second mixer. 
 
     
     
         6 . The cementitious material delivery system of  claim 5  wherein the mixer of  claim 1  and the second mixer share a common drive shaft. 
     
     
         7 . The cementitious material delivery system of  claim 1  further comprising:
 a reservoir of cementitious material configured to supply the flow of cementitious material to the flow divider; and 
 a decoupling accumulator configured to decouple the flow of cementitious material from the reservoir of cementitious material to the flow divider. 
 
     
     
         8 . The cementitious material delivery system of  claim 7  wherein the decoupling accumulator is of the flow-through type which passes cementitious material on a first-in-first-out basis. 
     
     
         9 . The cementitious material delivery system of  claim 7  wherein the decoupling accumulator includes a cylinder and a piston within the cylinder. 
     
     
         10 . The cementitious material delivery system of  claim 9  wherein a volume defined by the piston and the cylinder functions as the reservoir. 
     
     
         11 . The cementitious material delivery system of  claim 10  wherein the decoupling accumulator includes a hollow shaft connected to the piston. 
     
     
         12 . The cementitious material delivery system of  claim 11  wherein the hollow shaft has an end connected to the piston and an opposite end that functions as an accumulator inlet. 
     
     
         13 . The cementitious material delivery system of  claim 12  wherein the piston has a pushing surface and an opening within the pushing surface that has an area less than the area of the surface outlined by the pushing surface. 
     
     
         14 . The cementitious material delivery system of  claim 12  wherein the hollow shaft is attached to the piston such that cementitious material may flow from the accumulator inlet through the opening in the pushing surface of the piston. 
     
     
         15 . The cementitious material delivery system of  claim 14  wherein the cylinder includes an opening there through that is sized and positioned to allow cementitious material to escape from the cylinder only when the cylinder has been filled beyond a threshold amount. 
     
     
         16 . The cementitious material delivery system of  claim 7  wherein the decoupling accumulator includes a detection system configured to detect when the amount of cementitious material in the reservoir reaches a first amount and when it reaches a second amount. 
     
     
         17 . The cementitious material delivery system of  claim 16  further comprising a pump configured to be activated when the detection system detects that the amount of cementitious material in the reservoir has reached the first amount and to be deactivated when the detection system detects that the amount of cementitious material in the reservoir has reached the second amount. 
     
     
         18 . The cementitious material delivery system of  claim 16  wherein the detection system includes a first and second level sensor.