An MFC includes: a proportional valve; a mass flow sensor; a first flow line connecting from an outlet of the proportional valve through the mass flow sensor to an exit line; a second flow line joining the first flow line at a first junction located upstream of the mass flow sensor and at a second junction located downstream of the mass flow sensor; a switching valve placed such that the switching valve can regulate a flow of a gas through the first flow line or the second flow line; and a control device connected to provide a feedback control loop for regulating the proportional valve based on signals measured by the mass flow sensor, wherein the control device includes a program for keeping a rate of a flow exiting the exit line substantially constant when the flow is through the second flow line.

A method of stimulating a subterranean formation using a tubular member with one or more burst disks therein.

A heating system can include certain pressure sensitive features. These features can be configured to change from a first position to a second position based on a pressure of a fuel flowing into the feature. These features can include, fuel selector valves, pressure regulators, burner nozzles, and oxygen depletion sensor nozzles, among other features.

A system is provided to control fluid flow in a wastewater treatment system through wastewater level manipulation. The wastewater treatment system may include a wastewater treatment plant connected to a plurality of pump stations by a main. Each of the plurality of pump stations may include a wet well with a pump therein. The system may include a central server in communication with a sensor to sense a level of wastewater within the wet well. The pump may be automatically moved to an on position when the level of the wastewater in the wet well is at or above a first level and may be automatically moved to an off position when the level of the wastewater in the respective wet well is at or below a pump cutoff level. The central server may systematically manipulate the first level to selectively set the level of wastewater within the wet well.