Hot Pressing
Hot pressing refers to the art of applying heat in conjunction with mechanical pressure. Here in the oil milling plant, hot pressing means cooking the oil seeds with a hot pressing machine before pressing in order to extract more oil.
All main parts of hot pressing machine such as the worm shaft, pressing worms, cage bars and gears are made of high-grade alloy steel that have undergone hardening treatment. As a result, in spite of the constant conditions of high temperature and abrasion, durability prolongs their usable life for a considerable period of time.
The combination of steaming and roasting is also one of the features of this type of hot pressing machine. It can be regulated in accordance with the requirements of various oil-bearing materials, including pre-pressing temperatures to get high quality oils.
The whole process—from feeding, steaming, and roasting up to the discharge of oil and cake—goes on automatically and continuously. This makes it easy to operate the hot pressing machine, which results in the saving of labor.
Cold Pressing
Cold pressing or cold milling generally refers to the process of mechanically separating oil while pressing or crushing oil seeds using only the application of pressure, without the addition of heat or chemicals. By using a cold pressing machine the natural structure of the oil is maintained along with all of its natural characteristics.
Cold pressing does not actually mean pressing the seeds without any heat, as oil extraction cannot be done without the use of heat. Heat extracts oil from the seeds faster. In fact, it is hard to find oils that are pressed without heat.