There are two common classes of control systems, open loop control systems, and closed loop control systems. In an open loop control system, the control action from the controller is independent of the process output. A good example of this is a central heating boiler controlled only by a timer, so that heat is applied for a constant time, regardless of the temperature of the building.
Candles are made from many products, but predominantly paraffin wax is the most common. Paraffin wax is a petroleum by-product that is created from the sludge waste when crude oil is refined into gasoline.Sounds a bit gross. There are also soy wax candles which are made from the oil of soybeans, so it is a vegetable wax. Soy wax is a renewable resource.Most of the worldâs soy beans are primarily grown in Illinois, Iowa, and Indiana. Soy wax candles burn slower and not as hot as paraffin wax candles.here are also soy wax candles which are made from the oil of soybeans, so it is a vegetable wax. Soy wax is a renewable resource. Most of the worldâs soy beans are primarily grown in Illinois, Iowa, and Indiana.
Gel Wax. Fairly new to the candle industry, gel wax is used to make clear, see through candles. Often, these are the candles with a theme that usually have some type of objects embedded in the clear wax. Itâs one of the simplest and most enjoyable waxes to use. Merely heat it, add color, add scent and pour.