Cooling system and method
In accordance with one embodiment, a method is provided that includes providing a liquid nitrogen storage system configured to cool a supply of liquid nitrogen to a temperature below the vapor point of liquid nitrogen; coupling a piping system with the liquid nitrogen storage system to convey a portion of the supply of liquid nitrogen from the liquid nitrogen storage system; coupling the piping system with a liquid nitrogen control valve configured to control a flow of liquid nitrogen to at least one liquid nitrogen dispensing head; disposing the at least one liquid nitrogen dispensing head above a conveyance device operable to convey an aggregate stream of a concrete batching plant during use; and disposing the at least one liquid nitrogen dispensing head in a position to dispense an output flow of liquid nitrogen onto the aggregate stream of the concrete batching plant during use.
1 . A method for concrete mixing, the method comprising:
disposing a dispensing head above a conveyor device of a concrete batching plant, the conveyor device comprising a conveyor belt carrying an aggregate stream for a concrete batch to a mixing chamber of a concrete mixing device;
controlling, based on a control signal transmitted from a liquid nitrogen controller, a valve of an aggregate cooling system to control a flow of a supply of liquid nitrogen from a liquid nitrogen storage system to the dispensing head via a piping system;
venting, from the piping system, nitrogen gas generated by evaporation of the liquid nitrogen within the piping system, wherein the venting facilitates an uninterrupted flow of the liquid nitrogen to the dispensing head; and
dispensing an output flow of the liquid nitrogen from the dispensing head onto the aggregate stream for the concrete batch while the aggregate stream for the concrete batch is on the conveyor belt and being carried to the mixing chamber of the concrete mixing device;
wherein the dispensing head and the conveyer device are positioned outdoors such that the liquid nitrogen is exposed to ambient environmental temperature upon being dispensed from the dispensing head.
2 . The method of claim 1 , further comprising:
detecting, based on an aggregate sensor, a presence of the aggregate stream on the conveyor device, wherein controlling the flow of the supply of the liquid nitrogen is responsive to the presence of the aggregate stream on the conveyor device.
3 . The method of claim 2 , further comprising:
terminating the flow of the supply of the liquid nitrogen responsive to detecting that no aggregate is present on the conveyor device.
4 . The method of claim 1 , further comprising:
controlling, through a computerized control system communicatively coupled with the liquid nitrogen storage system, cooling of the supply of liquid nitrogen to thereby sub-cool the liquid nitrogen.
5 . The method of claim 4 , further comprising:
controlling, via the computerized control system, dispensing of the supply of liquid nitrogen in response to a signal received from a controller of the concrete batching plant.
6 . The method of claim 1 , wherein the aggregate stream comprises gravel and sand.
7 . The method of claim 1 , wherein controlling the flow of the supply of the liquid nitrogen is responsive to a signal from a batch controller.
8 . A method of mixing concrete in a system in which an aggregate stream is carried by a conveyor device toward a mixing chamber in which the aggregate is mixed to form the concrete, the method comprising:
controlling, by a computerized liquid nitrogen control system, a valve of an aggregate cooling system to control a supply flow of liquid nitrogen from a liquid nitrogen storage tank to a dispensing head via a piping system, wherein the dispensing head is positioned above the conveyor device;
venting, from the piping system, nitrogen gas generated by evaporation of the liquid nitrogen within the piping system, wherein the venting facilitates an uninterrupted flow of the liquid nitrogen to the dispensing head, and wherein the venting comprises causing the computerized liquid nitrogen control system to open a vent valve in response to actuation of a sensor in electrical communication with the computerized liquid nitrogen control system; and
dispensing the liquid nitrogen form the dispensing head onto the aggregate stream while the aggregate stream is carried by the conveyor device toward the mixing chamber; wherein the dispensing head, the piping system, and the conveyor device are positioned outdoors and exposed to ambient environmental temperature.
9 . The method of claim 8 , further comprising sub-cooling the liquid nitrogen in the liquid nitrogen storage tank to thereby discourage the evaporation of the liquid nitrogen within the piping system.
10 . The method of claim 8 , wherein the controlling the valve is based at least in part upon detecting presence of the aggregate stream on the conveyor device.
11 . The method of claim 8 , wherein the actuation of the sensor is indicative of back pressure on the liquid nitrogen in the piping system.
12 . The method of claim 8 , further comprising terminating the dispensing in response to a signal indicating that no aggregate is present on the conveyor device.
13 . The method of claim 8 , further comprising terminating the dispensing in response to a signal indicating that an insufficient quantity of the aggregate is present on the conveyor device.
14 . The method of claim 8 , further comprising terminating the dispensing in response to a signal indicating that the conveyance device has stopped moving the aggregate.
15 . The method of claim 1 , wherein the venting comprises causing a computerized liquid nitrogen control system to open a vent valve in response to actuation of a sensor in electrical communication with the computerized liquid nitrogen control system.
16 . The method of claim 15 , wherein the actuation of the sensor is indicative of back pressure on the liquid nitrogen in the piping system.
17 . The method of claim 1 , wherein the mixing chamber of the concrete mixing device is a mixing chamber of a concrete mixing truck.
18 . The method of claim 1 , wherein the piping system is positioned outdoors and exposed to ambient environmental temperatures.