Uses of vacuum pumps, types of vacuum pumps

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A vacuum pump is a rotary variable-volume vacuum pump that requires a pre-pump in order to be used across a wide range of pressures; it offers a high pumping speed, is not sensitive to dust and water vapor present in the gas to be evacuated, and is widely used in industries such as metallurgy, chemicals, food processing, and electronic coating. A machine that draws gas out of a device, thereby reducing the pressure inside it to below one atmosphere, is called a vacuum pump. In fact, a vacuum pump is a type of gas transfer machine that transports gas from an environment with a pressure lower than atmospheric pressure to an environment at atmospheric pressure or equal to it. Flow rate and vacuum level are the two most important factors in selecting the appropriate vacuum product. First, flow rate: it determines the size of the product; the higher the flow rate requirement, the larger the volume of the product, and consequently the higher the power of the motor required. Second, vacuum level: it determines what type of structure the product should have. Vacuum level is expressed in terms of gauge pressure and absolute pressure. The types of vacuum pumps include water ring vacuum pumps and directly coupled vacuum pumps. Uses of vacuum pumps in the chemical industry: Vacuum pumps are often used to create a certain level of vacuum in order to carry out various process operations. For example, under the suction of a vacuum pump, the filtration speed of the solution increases ； When separating liquid mixtures, the distillation temperature can be lowered to prevent coking and decomposition that may occur during high-temperature distillation ； The temperature of the dry solid material drops faster ； In a heat pipe heat exchanger, the heat pipes are evacuated and then filled with distilled water, which **accelerates** the heat transfer rate, among other things. The electronics industry and the defense industry often require higher vacuum levels. With the continuous development of vacuum technology, the range of vacuums that can be achieved is becoming increasingly wide, from an absolute pressure of 1.0133×105 Pa to 133.32×10-5 Pa. Therefore, the vacuum regions are classified as follows: Rough vacuum: pressure range of 101.3×10³ to 1.3332×10³ Pa (10–760 mmHg). Low vacuum: pressure range of 1.3332×10³ to 133.2×10⁻² Pa (10⁻²–10 mmHg). Medium vacuum: pressure range of 133.2×10⁻² to 133.2×10⁻⁷ Pa (10⁻⁴–10⁻² mmHg). High vacuum: pressure range of 133.2×10⁻⁴ to 133.2×10⁻⁷ Pa (10⁻⁷–10⁻⁴ mmHg). Ultra-high vacuum: pressure range below 133.2×10⁻⁷ Pa (below 10⁻⁷ mmHg). In chemical production, operational conditions within the rough and low vacuum ranges are generally sufficient to meet the production requirements. Vacuum pumps can be classified into dry vacuum pumps and wet vacuum pumps based on their operating conditions. The Yu-type vacuum pump can only remove gas from the equipment, and its vacuum level can reach 96y/—99.9}/ ； A wet vacuum pump can draw gas-liquid mixtures, achieving a vacuum level of 80%–85%. The key performance parameters of a vacuum pump include the pumping speed and ultimate vacuum. 1. Pumping speed: The volume of gas pumped per unit of time is called the pumping speed, denoted by the symbol S. Its units are 1113/h or d/s, and it indicates the pumping capacity of the vacuum pump. 2. Ultimate vacuum: The ultimate vacuum, also known as residual pressure, refers to the lowest absolute pressure value that a vacuum pump can achieve; it is denoted by the symbol P₀ and is measured in Pa. 3. Vacuum level and percentage of vacuum: The vacuum level is the difference between atmospheric pressure and the absolute pressure in the vacuum system; it is denoted by the symbol P, with the unit being Pa. That is p. -101.3×10^3_p (Pa), where p is the absolute pressure in the vacuum system, in Pa. The vacuum percentage is the ratio of the vacuum level to atmospheric pressure, that is, p. (%) The values of absolute pressure, vacuum level, and the percentage of vacuum are shown in Table 5–18. Table S—18 Absolute pressure. Vacuum degree percentage chart: Table 5-18 shows the relationship among absolute pressure, vacuum degree, and vacuum degree percentage. For example, if the percentage of vacuum is known to be 80%, it can be determined that the absolute pressure at this point is 152 mmHg, while the vacuum level is 608 mmHg. If the ultimate vacuum of a vacuum pump is known to be 114×133.32 Pa, then its vacuum degree as a percentage can be determined to be 85%, and the vacuum level it can achieve is 646×133.32 Pa. When a vacuum pump is in operation, it continuously removes the gas from within the container, reducing the amount of gas there and causing the pressure to drop gradually. When the pressure inside the container falls below a certain minimum value, the following situation often occurs: the liquid in the container vaporizes ； The volume of gas leaking back on the high-pressure side of the pump is equal to the pumping capacity of the vacuum pump ； The excessive pressure ratio of the vacuum pump causes the pumping process to stop. At this point, the pressure inside the container will no longer decrease, so it is not possible to reduce the pressure to absolute vacuum indefinitely. There are many types of vacuum pumps. Based on their structural design, they can be classified into several major categories, such as reciprocating vacuum pumps, rotary vacuum pumps – also known as vane vacuum pumps or water ring vacuum pumps – and water jet vacuum pumps. Luoyang Napute New Materials Technology Co., Ltd. 13603889856 0379-60679266