The present disclosure relates to a control method of a gas furnace comprising a step for measuring an indoor temperature, a step for comparing the indoor temperature with a set temperature for heating, and a step for operating the gas furnace in weak heating with a predetermined heating capacity which is lower than a maximum heating capacity of the gas furnace, when the set temperature for heating is higher than the indoor temperature by a temperature value which is less than a predetermined temperature value, wherein the predetermined heating capacity for weak heating is maintained at a current heating capacity for weak heating, when the gas furnace operates in weak heating, and when an operating duration with the current heating capacity for weak heating is less than a first time value.

A power generator for use to generate power for metrology hardware like gas meters and flow measuring devices. The power generator may use flame-less combustion that creates heat from fuel gas. The heat causes a temperature differential. The power generator may include a thermal electric generator that generates an electrical signal in response to the temperature differential.

A power generator for use to generate power for metrology hardware like gas meters and flow measuring devices. The power generator may use flame-less combustion that creates heat from fuel gas. The heat causes a temperature differential. In one implementation, the power generator may include a thermal electric generator that generates an electrical signal in response to the temperature differential.

A method for controlling a gas furnace including measuring an indoor temperature, comparing the indoor temperature with a set temperature for heating, and operating the gas furnace in weak heating with a predetermined heating capacity, which is lower than a maximum heating capacity of the gas furnace, when the set temperature for heating is higher than the indoor temperature by a temperature value, which is less than a predetermined temperature value. The predetermined heating capacity for weak heating is maintained at a current heating capacity for weak heating, when the gas furnace operates in weak heating, and when an operating duration with the current heating capacity for weak heating is less than a first time value.

A two-stage fluid control valve includes a first stage mechanical control valve movable between an open position and a leak-free closed position, and a second stage microvalve configured to control the flow of fluid through a fluid outlet of the two-stage fluid control valve when the first stage mechanical control valve is in the open position.

The design and assembly of a smart device constituent of a micro-machined (a.k.a. MEMS, Micro Electro Mechanical Systems) mass flow sensor and an electrically controllable valve for applications in safety enhancement and intermit connectivity for residential or commercial gas range is disclosed in the present invention. The said smart device detects the gas flow at the unattended situations and sends information to the destined mobile devices of the users via the network such that it enables the users to remotely execute actions of either shutting off the gas supply or call for relevant party's immediate attention. The said smart device shall also automatically shut off the gas supply should the transmitted signal to users failed to send feedback signal such that it can prevent the safety incidents due to leakage or overheating or even fires. The capability of the MEMS mass flow sensor shall also provide the thermal value measurement of the supplied gases and enable the user to program the gas range for making complete tasks of cooking substances in the unattended situation.

A two-stage fluid control valve includes a first stage mechanical control valve movable between an open position and a leak-free closed position, and a second stage microvalve configured to control the flow of fluid through a fluid outlet of the two-stage fluid control valve when the first stage mechanical control valve is in the open position.