A system for pouring concrete around a flexible duct assembly. The system includes a balloon deployment system for deploying and retracting a balloon system within the duct assembly. The balloon deployment system is displaceable along a length of the duct assembly and follows a level of concrete being poured therearound. A method for pouring concrete around a flexible duct assembly is also disclosed.

A system for pouring concrete around a flexible duct assembly. The system includes a balloon deployment system for deploying and retracting a balloon system within the duct assembly. The balloon deployment system is displaceable along a length of the duct assembly and follows a level of concrete being poured therearound. A method for pouring concrete around a flexible duct assembly is also disclosed.

A coal and gas outburst monitoring device includes the insertion and anchoring assembly, and the pump drainage and monitoring mechanism; the insertion and anchoring assembly is vertically inserted and distributed on the sidewall of surrounding rock of coal mine roadway, and the insertion and anchoring assembly can monitor the stress change data in the sidewall of surrounding rock in real time; the pump drainage and monitoring mechanism is erected within the coal mine roadway, and the pump drainage and monitoring mechanism can cooperate with the insertion and anchoring assembly to perform the gas pump drainage monitoring for the sidewall of surrounding rock of goaf, and to obtain the gas seepage monitoring data in the surface layer and the inner layer of sidewall of surrounding rock. Thus, comparing with the database mechanism, the accurate and advanced predictions for the gas outburst can be made.

A coal and gas outburst monitoring device includes the insertion and anchoring assembly, and the pump drainage and monitoring mechanism; the insertion and anchoring assembly is vertically inserted and distributed on the sidewall of surrounding rock of coal mine roadway, and the insertion and anchoring assembly can monitor the stress change data in the sidewall of surrounding rock in real time; the pump drainage and monitoring mechanism is erected within the coal mine roadway, and the pump drainage and monitoring mechanism can cooperate with the insertion and anchoring assembly to perform the gas pump drainage monitoring for the sidewall of surrounding rock of goaf, and to obtain the gas seepage monitoring data in the surface layer and the inner layer of sidewall of surrounding rock. Thus, comparing with the database mechanism, the accurate and advanced predictions for the gas outburst can be made.

A duct includes a polymeric duct wall that circumscribes a fluid-conveyance passage. The polymeric duct wall includes, relative to the fluid-conveyance passage, an inner surface and an outer surface. An electrically conductive coating is disposed on at least one of the outer surface and the inner surface.

A duct includes a polymeric duct wall that circumscribes a fluid-conveyance passage. The polymeric duct wall includes, relative to the fluid-conveyance passage, an inner surface and an outer surface. An electrically conductive coating is disposed on at least one of the outer surface and the inner surface.

A coal and gas outburst monitoring device includes the insertion and anchoring assembly, and the pump drainage and monitoring mechanism; the insertion and anchoring assembly is vertically inserted and distributed on the sidewall of surrounding rock of coal mine roadway, and the insertion and anchoring assembly can monitor the stress change data in the sidewall of surrounding rock in real time; the pump drainage and monitoring mechanism is erected within the coal mine roadway, and the pump drainage and monitoring mechanism can cooperate with the insertion and anchoring assembly to perform the gas pump drainage monitoring for the sidewall of surrounding rock of goaf, and to obtain the gas seepage monitoring data in the surface layer and the inner layer of sidewall of surrounding rock. Thus, comparing with the database mechanism, the accurate and advanced predictions for the gas outburst can be made.

A coal and gas outburst monitoring device includes the insertion and anchoring assembly, and the pump drainage and monitoring mechanism; the insertion and anchoring assembly is vertically inserted and distributed on the sidewall of surrounding rock of coal mine roadway, and the insertion and anchoring assembly can monitor the stress change data in the sidewall of surrounding rock in real time; the pump drainage and monitoring mechanism is erected within the coal mine roadway, and the pump drainage and monitoring mechanism can cooperate with the insertion and anchoring assembly to perform the gas pump drainage monitoring for the sidewall of surrounding rock of goaf, and to obtain the gas seepage monitoring data in the surface layer and the inner layer of sidewall of surrounding rock. Thus, comparing with the database mechanism, the accurate and advanced predictions for the gas outburst can be made.

System and method for shaping a duct section. The duct section is configured to be expandable from a flattened configuration to an expanded configuration. The system includes an inflatable enclosure insertable within the duct section while being in the flattened configuration. The inflatable enclosure defines an opening for inflating the inflatable enclosure. The system also includes a blower for inflating the inflatable enclosure through the opening from a deflated configuration to an inflated configuration. In use, when the inflatable enclosure is inserted within the duct section, the blower inflates the inflatable enclosure through the opening from the deflated configuration to the inflated configuration, whereby the duct section expands from the flattened configuration to the expanded configuration as the inflatable enclosure pushes against the duct section from within.