Process and apparatus for the production of plastic materials and plastic foams from liquid reactive chemical components employing modified injection nozzles

Claim 1

Apparatus for insuring synchronized opening and closing of needle valves of injection nozzles employed in the production of plastic materials or plastic foams wherein liquid materials of the plastic material or foam are separately injected under relatively high pressure through such nozzles into a mixing chamber, each of the nozzles including a housing having an annular bore therein, the bore at the lower end of the housing forming a discharge orifice for flow of material therethrough, a needle valve disposed in the annular bore movable between a closed position and an open position, the valve in closed position seating against the discharge orifice and preventing flow of the material therethrough, bias means biasing the needle valve to a normally closed position, conduit means in the housing communicating with the discharge orifice and the lower portion of the needle valve seated against the discharge orifice, the pressure of the material metered into the conduit operating to force the needle valve to an open position and allowing flow of the material therethrough to the mixing chamber, the improvement comprising means operatively connected to the valve of each nozzle for controlling pre- and post-flow of the liquid material into the mixing chamber.

Claim 7

A method for insuring synchronized opening and closing of needle valves of injection nozzles employed in the production of plastic materials or plastic foams wherein liquid materials of the plastic material or foam are separately injected under relatively high pressure through such nozzles into a mixing chamber with closing and opening of the needle valves controlled, respectively, by bias means and the pressure of the material flowing therethrough to eliminate pre- and post-flow of the liquid materials, each of the injection nozzles including a signal means producing an electro-visual signal mounted to indicate movement of the needle valve of each nozzle from a closed position to an open position or an open position to a closed position, and adjusting means for adjusting the pressure of the bias means forcing the needle valve of each nozzle to a normally closed position, comprising: adjusting the pressure exerted on the bias means of each nozzle until the electro-visual signal means on each nozzle lights substantially simultaneously when the needle valves are opened, indicating synchronized opening of the needle valve of each nozzle, thereby eliminating pre-flow of the injected materials.

Claim 8

A method for insuring synchronized opening and closing of needle valves of injection nozzles employed in the production of plastic materials or plastic foams wherein liquid materials of the plastic material or foam are separately injected under relatively high pressure through such nozzles into a mixing chamber with closing and opening of the needle valves controlled, respectively, by bias means and the pressure of the material flowing therethrough to eliminate pre- and post-flow of the liquid materials, each of the injection nozzles including a signal means producing an electro-visual signal mounted to indicate movement of the needle valve of each nozzle from a closed position to an open position or an open position to a closed position, and adjusting means for adjusting the pressure of the bias means forcing the needle valve of each nozzle to a normally closed position, comprising: adjusting the pressure exerted on the bias means of each nozzle until the electro-visual signal means on each nozzle lights substantially simultaneously when the needle valves are opened, indicating synchronized opening of the needle valve of each nozzle, thereby eliminating pre-flow of the injected materials.

Claim 9

A method for insuring synchronized opening and closing of needle valves of injection nozzles employed in the production of plastic materials or plastic foams wherein liquid materials of the plastic material or foam are separately injected under relatively high pressure through such nozzles into a mixing chamber with closing and opening of the needle valves controlled, respectively, by bias means and the pressure of the material flowing therethrough to eliminate post-flow of the liquid materials and wherein each of the injection nozzles includes pressure means to exert pressure on the needle valve of each nozzle in addition to that exerted by the bias means regulating the normal opening pressure of the needle valves, and control means connected to the pressure means of each injection noZzle to simultaneously relieve the additional pressure on the needle valves to allow them to open substantially simultaneously and apply additional pressure forcing the valves to close substantially simultaneously, comprising: simultaneously imposing additional pressure on the needle valves by activating the pressure means associated with the needle valves of each nozzle to force them to closed position with additional pressure over and above the pressure of the bias means to eliminate post-flow or reactants into the mixing chamber, and simultaneously removing the additional pressure on the needle valves of each nozzle to allow them to open at substantially the same time, thereby eliminating pre-flow of reactants into the mixing chamber.

Claim 10

A method for insuring synchronized opening and closing of needle valves of injection nozzles employed in the production of plastic materials or plastic foams wherein liquid materials of the plastic material or foam are separately injected under relatively high pressure through such nozzles into a mixing chamber with closing and opening of the needle valves controlled, respectively, by bias means and the pressure of the material flowing therethrough to eliminate post-flow of the liquid materials and wherein each of the injection nozzles includes pressure means to exert pressure on the needle valve of each nozzle in addition to that exerted by the bias means regulating the normal opening pressure of the needle valves, and control means connected to the pressure means of each injection noZzle to simultaneously relieve the additional pressure on the needle valves to allow them to open substantially simultaneously and apply additional pressure forcing the valves to close substantially simultaneously, comprising: simultaneously imposing additional pressure on the needle valves by activating the pressure means associated with the needle valves of each nozzle to force them to closed position with additional pressure over and above the pressure of the bias means to eliminate post-flow or reactants into the mixing chamber, and simultaneously removing the additional pressure on the needle valves of each nozzle to allow them to open at substantially the same time, thereby eliminating pre-flow of reactants into the mixing chamber.