The pilot light is a small gas fire, usually natural gas or liquid oil gas, which serves as a source of ignition for stronger gas burners. Initially, the pilot light remains permanently lit; However, this is wasteful of gas. It is now more common to power electrically burners, but gas pilot lights are still used when high-energy sources are needed, such as when powering a large burner.
The term "pilot lamp" is also used occasionally for a power indicator light that illuminates to indicate that a power supply is available, or that an electrical device is operating. Such indicators are initially incandescent or fluorescent lights, but now are usually LEDs.
Video Pilot light
Usage
Common applications include household water heaters, central heating systems, fireplaces, flamethrowers, and hot air balloons. While most commercial kitchens still rely on pilot lights for burners, ovens, and grills, today's residential systems use electric ignition. This is more commonly known as standby on modern remote control fires.
Maps Pilot light
Security protection
In natural gas furnaces, water heaters, and heating systems, a safety breaker switch is usually included so that the gas supply to the pilot and heating system is turned off by an electrically operated valve if the pilot light is off. This cut-off button usually detects the pilot light in one of several ways:
- Flame rectification device.
- Sensors containing mercury are used to detect the heat of pilot light. The contraction of mercury produces enough pressure to operate an electrical switch that disrupts the flow of electricity and closes the gas valve when the pilot light goes out.
- The photoresistor is used to detect light from pilot lights. When the pilot light is off, the electrical circuit connected to the photoresistor closes the gas valve.
- The use of a pilot or thermocouple generator in a flame provides a secure heating device as it generates sufficient electric current from a flame to withstand an open gas valve. If the pilot light is off, the pilot generator will cool down and the current stops, closing the gas valve.
Other units use a non-electric approach, in which the pilot heats a bimetallic element or a gas-filled tube to exert mechanical pressure to keep the gas valve open. If the pilot fails, the valve closes. To restart the system, the valve must be opened manually and the pilot lights up, and then the valve must remain open until the element heats up enough to hold the valve open. Non-electric schemes are suitable for systems that do not use electricity.
The above method is an example of using "fail-safe" security protection.
Energy waste
In domestic heating systems with pilot lamps, it is estimated that half of the total energy use comes from pilot light, with each average pilot light using between 70 and 500 watts of gas power (between 8 and 16 gigajoules/year). Heat from pilot light in many appliances (furnace, space heater, water heater) is generally released in the same room as the main burner. The energy loss is much smaller for pilot lamps in the heating chamber than any other product, because space heaters heat up smaller enclosed spaces and contribute more significantly to heat the room. The efficiency of the appliance of the local heated fuel cell exhaust in the pilot lamp mode is similar to the efficiency of the tool measured at reduced power from the appliance, which is between 65 - 95% efficiency based on the low calorie value of the consumed gas, making part of the pilot's energy consumption light becomes a useful heat.
The modern alternative
An alternative to a pilot lamp is a system for creating a high voltage electric arc or spark between two electrodes, to turn on the gas that flows into the burner. A safe-failing design for such a system requires a burner flame to be detected by passing an electric current through a flame, received by a flame rectification circuit within the ignition controller connected to the gas valve. Flame alignment occurs when electrons flow through a blazing fire, controlled by an ignition controller and know the flame is there, keeping the gas valve open. If the appliance loses gas or flame is extinguished, ignition controller does not see a flame, closes the gas valve.
The red-hot surface can also be used to provide ignition. Such Igniters are often made from silicon carbide, silicon nitride, or other durable materials under excessive heat exposure. Hot surface ignition is commonly used in cooking ovens, boilers, and modern gas furnaces.
The disadvantage for a modern alternative that requires high voltage is that the equipment is useless during a power outage. Pilot solutions work independently of the electrical system. However, some equipment may be lit with an external fire source during a power outage. This may include cooking stoves and ovens, but not heating boilers that are enclosed in the room or dependent on electricity to operate the pump.
Another disadvantage of using combustion equipment connected to natural chimneys without pilot light is the lack of an initial draft in the chimney. Without the pilot light, the chimney can cool completely to the outside temperature, so there is no chimney dumped in this case, or even a negative draft draft if the outside temperature is higher than the inside temperature of the house. This case has a backflow in the chimney. This is the reason to feel the smell of soot during summer in the chimney gap. If there is a backflow in the chimney, it is possible that cold air and gas chimney enter the utility chamber through the opening of the gas drain switch, which can cause high levels of carbon monoxide in the room air, causing the possibility of death or permanent disability. In such situations there is no strong physical effect that will drive the exhaust gas to the chimney, so that the force, which causes the backflow in the chimney can be determinative. According to statistics, the "preliminary design" in the chimneys guaranteed by the permanent pilot has an important role to prevent an increase in the number of carbon monoxide poisoning. So in terms of open fired equipment and natural chimneys, the goals of energy saving and the opposite security aspects.
References
Source of the article : Wikipedia
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