Gas stove
A gas stove is a stove that is fuelled by combustible gas such as syngas, natural gas, propane, butane, liquefied petroleum gas or other flammable gas. Before the advent of gas, cooking stoves relied on solid fuels such as coal or wood. The first gas stoves were developed in the 1820s and a gas stove factory was established in England in 1836. This new cooking technology had the advantage of being easily adjustable and could be turned off when not in use. The gas stove, however, did not become a commercial success until the 1880s, by which time  supplies of piped gas were available in cities and large towns in Britain. The stoves became widespread on the European Continent and in the United States in the early 20th century. Gas stoves became more common when the oven was integrated into the base and the size was reduced to better fit in with the rest of the kitchen furniture. By the 1910s, producers started to enamel their gas stoves for easier cleaning. Ignition of the gas was originally by match and this was followed by the more convenient pilot light. This had the disadvantage of continually consuming gas. The  oven still needed to be lit by match and accidentally turning on the gas without igniting it could lead to an explosion. To prevent these types of accidents, oven manufacturers developed and installed a safety valve called a flame failure device for gas hobs (cooktops) and ovens. Most modern gas stoves have electronic ignition, automatic timers for the oven and extractor hoods to remove fumes. Gas stoves are a significant source of indoor air pollution, and require good ventilation to maintain acceptable air quality. History. The first gas stove was developed on 8 March 1802 by Zachäus Winzler (), but this  along with other attempts remained isolated experiments. James Sharp patented a gas stove in Northampton, England in 1826 and opened a gas stove factory in 1836. His invention was marketed by the firm Smith & Philips from 1828. An important figure in the early acceptance of this new technology, was Alexis Soyer, the renowned chef at the Reform Club in London. From 1841, he converted his kitchen to consume piped gas, arguing that gas was cheaper overall because the supply could be turned off when the stove was not in use. A gas stove was shown at the World Fair in  London in 1851, but it was only in the 1880s that the technology became a commercial success in England. By that stage a large and reliable network for gas pipeline transport had spread over much of the country, making gas relatively cheap and efficient for domestic use. Gas stoves only became widespread on the European Continent and in the United States in the early 20th century. Early gas stoves were rather unwieldy, but soon the oven was integrated into the base and the size was reduced to fit in better with the rest of the kitchen furniture. In the 1910s , producers started to enamel their gas stoves for easier cleaning. Ignition. Gas stoves today use two basic types of ignition sources, standing pilot and electric. A stove with a standing pilot has a small, continuously burning gas flame (called a pilot light) under the cooktop. The flame is between the front and back burners. When the stove is turned on, this flame lights the gas flowing out of the burners. The advantage of the standing pilot system is that it is simple and completely independent of any outside power source. A minor drawback is that the flames continuously consume fuel  even when the stove is not in use. Early gas ovens did not have a pilot. One had to light these manually with a match. If one accidentally left the gas on, gas would fill the oven and eventually the room. A small spark, such as an arc from a light switch being turned on, could ignite the gas, triggering a violent explosion. To prevent these types of accidents, oven manufacturers developed and installed a safety valve called a flame failure device for gas hobs (cooktops) and ovens. The safety valve depends on a thermocouple that sends a signal to  the valve to stay open. Although most modern gas stoves have electronic ignition, many households have gas cooking ranges and ovens that need to be lit with a flame. Electric ignition stoves use electric sparks to ignite the surface burners. This is the "clicking sound" audible just before the burner actually lights. The sparks are initiated by turning the gas burner knob to a position typically labeled "LITE" or by pressing the 'ignition' button. Once the burner lights, the knob is turned further to modulate the flame size. Auto reignition is an elegant refinement: the user need not know or  understand the wait-then-turn sequence. They simply turn the burner knob to the desired flame size and the sparking is turned off automatically when the flame lights. Auto reignition also provides a safety feature: the flame will be automatically reignited if the flame goes out while the gas is still on—for example by a gust of wind. If the power fails, surface burners must be manually match-lit. Electric ignition for ovens uses a "hot surface" or "glow bar" ignitor. Basically it is a heating element that heats up to gas's ignition temperature. A sensor detects when  the glow bar is hot enough and opens the gas valve. Also stoves with electric ignition must be connected with gas protection mechanisms such as gas control breaker. Because of this many manufacturers supply stoves without electricity plug. Features. Burner heat. One of the important properties of a gas stove is the heat emitted by the burners. Usually, burner heat is specified in terms of BTUs (British Thermal Units), and represent the heat produced in one hour. Often, a gas stove will have burners with different heat output ratings. For example, a gas cooktop may have a high output burner , often in the range 10,000 to 20,000 BTU, and a mixture of medium output burners, 5,000 to 10,000 BTU, and low output burners, 3,000 BTU or less. The high output burner is suitable for boiling a large pot of water quickly, sautéing and searing, while the low output burners are good for simmering. Some high-end cooktop models provide higher range of heat and heavy-duty burners that can go up to 20,000 BTU or even more. Depending on the type of cooking you do, the higher heat capability burners can be either beneficial or complete waste of money. Design  and layout. In the last few years, appliance manufacturers have been making innovative changes to the design and layout of gas stoves. Most of the modern cooktops have come with lattice structure which usually covers the complete range of the top, enabling sliding of cookware from one burner to another without lifting the containers over the gaps of cooktop. Some modern gas stoves also have central fifth burner or an integrated griddle in between the outer burners. Size. The size of a kitchen gas stove usually ranges from to even (industrial models). Almost all the manufacturers have been developing several  range of options in size range. Combination of range and oven are also available which usually come in two styles: slide in and freestanding. Usually, there isn't much of a style difference in between them. Slide-in come with lips on their either side and controls over the front along with burner controls. Freestanding gas range cooktops have solid slides and controls placed behind the cooktop. Oven. Many stoves have integrated ovens. Modern ovens often include a convection fan inside the oven to provide even air circulation and lets the food cook evenly. Some modern ovens come with temperature  sensors which allows close control of baking, automatically shut off after reaching certain temperature, or hold on to particular temperature through the cooking process. Ovens may also have two separate oven bays which allows cooking of two different dishes at the same time. Programmable controls. Many gas stoves come with at least few modern programmable controls to make the handling easier. LCD displays and some other complex cooking routines are some of the standard features present in most of the basic and high-end manufacturing models. Some of the other programmable controls include precise pre-heating, automatic pizza, cook timers  and others. Safety factors. Modern gas stove ranges are safer than older models. Two of the major safety concerns with gas stoves are child-safe controls and accidental ignition. Some gas cooktops have knobs which can be accidentally switched on even with a gentle bump. Health concerns. Carbon monoxide, formaldehyde, and nitrogen dioxide from gas stoves contribute to indoor air pollution, and can present a risk factor for respiratory illnesses such as asthma or chronic obstructive pulmonary disease. Climate impact. In 2022, the methane emissions from gas stoves in the United States were estimated as equivalent to the greenhouse gas  emissions of 500,000 cars. About 80% of methane emissions occur when stoves are turned off, as the result of leaks in gas lines and fittings. New York City, San Francisco and Seattle have curtailed installation of gas stoves and appliances in new construction, for reasons of health, indoor air quality, and climate protection.