The pump is a kind of machinery to stop the liquid transportation. The chemical centrifugal pump is one of them. It makes the liquid flowing through the impeller suffer the centripetal force through the impeller, and improves the mechanical energy of the liquid, so as to stop the liquid transportation. It is a machine to increase the liquid energy.
Due to the special requirements of chemical consumption for pumps, chemical centrifugal pumps have the following characteristics compared with other centrifugal pumps:
(1) Can meet the needs of chemical process: in chemical consumption, pumps should not only guarantee liquid materials and provide the necessary pressure for process requirements, but also ensure the quantity of materials to be guaranteed. In certain chemical unit operation, the flow and head of the requested pumps should be stable, and the high efficiency and reliable operation of pumps should be adhered to.
(2) Corrosion resistance: the medium of chemical pump, including raw materials, reaction intermediates, etc. are often corrosive medium. This requires that the data of the pump be properly and reasonably selected to ensure the safety, stability and short-life fate of the pump.
(3) High temperature and low temperature resistance: high temperature medium guaranteed by chemical pumps, including process liquid materials, as well as heat carrying liquid required and produced in response process. For example: condensate pump, boiler feed pump, heat transfer oil pump. There are also many kinds of low-temperature media that chemical pumps provide,
(4) Wear resistance and scour resistance: because the logistics of chemical pump includes suspended solid particles, and the impeller and cavity of pump also work under high pressure and high flow rate, the surface maintenance layer of pump parts is damaged, and its service life is short, so it is necessary to improve the wear resistance and scour resistance of chemical pump, which requires the pump data to select wear-resistant manganese steel, ceramics, cast iron, etc., and select wear-resistant manganese steel, ceramics, cast iron, etc Scoured titanium, manganese steel, etc.
(5) Reliable operation: reliable operation of chemical pumps includes two meanings: first, long-term operation without fault; second, stable operation of various parameters. The reliability of operation is very important for chemical consumption. If the pump often breaks down, it will not only cause frequent shutdown, which will affect the output and economic benefits, but also cause accidents of chemical system sometimes. The fluctuation of the rotation speed of the chemical pump will cause the fluctuation of the flow and the pressure at the pump outlet, make the chemical consumption unable to stop normally or the response in the system affected, and the material can not be balanced, which not only leads to waste, but also leads to the decline of the production quality or the scrapping of the product.
(6) No leakage or little leakage: most of the media guaranteed by chemical pumps are flammable, explosive, toxic and harmful liquids. Once leakage occurs, the environment will be seriously polluted, personal safety and physical and mental health of employees will be endangered, and it is not in line with the requirements of no leakage factories and clean culture factories. Therefore, it is necessary to ensure that chemical pumps do not leak during operation. New technologies and new materials shall be used for pump sealing according to regulations Process operation, high quality maintenance.
(7) Critical liquid: a critical liquid that often vaporizes when temperature increases or pressure decreases. Chemical pumps sometimes guarantee the critical state of liquid, once the liquid vaporizes in the pump, it is easy to produce cavitation damage, which requires the pump to have high cavitation resistance. At the same time, the vaporization of the liquid may cause friction and scuffing in the dynamic and static parts of the pump, which requires a larger clearance. In order to prevent the mechanical seal, packing seal and labyrinth seal from being destroyed by dry friction due to the vaporization of liquid, this kind of chemical pump must have the structure of fully cleaning the gas in the pump.