In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. It performs the activity of managing or maintaining a range of values in a machine. The measurable property of a device is managed closely by specified conditions or an advance set value; or it can be a variable according to a predetermined arrangement scheme. It can be used generally to connote any set of various controls or devices for regulating or controlling items or objects. Regulators can be designed to control anything from gases or fluids, to light or electricity. Speed can be regulated by electronic, mechanical, or electro-mechanical means. Such instances include: Electronic regulators as used in modern railway sets where the voltage is raised or lowered to control the speed of the engine; Mechanical systems such as valves as used in fluid control systems. Purely mechanical pre-automotive systems included such designs as the Watt centrifugal governor whereas modern systems may have electronic fluid speed sensing components directing solenoids to set the valve to the desired rate.
Designed in 1835, the gas regulator's concept is easy, and its impact has been long-lasting. There are various types of regulators, but their function is the same: to use a valve system to control natural gas or propane pressure or other gas flow. Common appliances that use regulators include gas stoves, propane grills, or oxy-fuel bottles for welding. Each type of regulator's components consists of a set spring attached to a rod that runs down from a set screw through a diaphragm into the valve. There are three primary operating components working together to regulate the pressure within the valve. The loading mechanism determines the delivery pressure. Most often, it is a spring. The sensing element, or diaphragm, senses the force against the spring. Finally, the control element accomplishes the reduction of the inlet pressure through to the outlet pressure. Gas enters the regulator's chamber, putting pressure on the diaphragm. The diaphragm then moves upward as controlled by the set spring. This allows a specific flow of fuel from the source to the appliance or device. Adjusting the control knob determines the rate of flow and the pressure. Turning clockwise will push the diaphragm down and allow more gas to come into the valve. Turn counter-clockwise to reduce the amount of fuel and pressure.
Liquefied petroleum gas (LPG, LP gas, or condensate) is a fuel gas made of petrol which contains a flammable mixture of hydrocarbon gases, most commonly propane, butane, and propylene. However, the latter two typically compose 5% or less of the mixture. LPG is used as a fuel gas in heating appliances, cooking equipment, and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel, it is often referred to as autogas. Varieties of LPG that are bought and sold include mixes that are mostly propane (C3H8), mostly butane (C4H10), and, most commonly, mixes including both propane and butane. In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane. In the United States, mainly two grades of LPG are sold: commercial propane and HD-5. These specifications are published by the Gas Processors Association (GPA) and the American Society of Testing and Materials. Propane/butane blends are also listed in these specifications. Propylene, butylenes and various other hydrocarbons are usually also present in small concentrations such as C2H6, CH4, and C3H8. HD-5 limits the amount of propylene that can be placed in LPG to 5% and is utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The internationally recognized European Standard is EN 589. In the United States, tetrahydrothiophene (thiophane) or amyl mercaptan are also approved odorants, although neither is currently being utilized. An LPG regulator is a device that maintains a stable downstream pressure regardless of changes in gas flow and upstream pressure. Among them, the LPG jumbo regulator and the LPG quick-on regulator are typical representatives.
