Many people don't know much about pumps, let alone distinguish them by type, function and principle. This time you can take a look at this article, Xiaobian takes you to know the various pumps and how they work, so that you will not be stupid when you face them. A pump is a type of fluid machine, and a fluid machine refers to a mechanical device that uses a fluid as a working medium and an energy carrier. Fluid machines can be divided into prime movers (turbines, steam turbines) and working machines (pumps, fans, compressors) depending on the direction of energy transfer. The pump belongs to the working machine, that is, the machine that consumes energy. From the performance range of the pump, the flow rate of the giant pump can reach several hundred thousand cubic meters per hour, while the flow rate of the micro pump is below several tens of milliliters per hour; the pressure of the pump can be from normal pressure to 19.61Mpa (200kgf/). Cm2) or more; the temperature of the liquid to be transported is at least -200 degrees Celsius, and the highest is above 800 degrees Celsius. Pumps transport a wide variety of liquids, such as transport water (clean water, sewage, etc.), oil, acid and alkali, suspension, and liquid metal. In the chemical and petroleum sectors, raw materials, semi-finished products and finished products are mostly liquids, and the preparation of raw materials into semi-finished and finished products requires a complicated process in which the pump acts as a pressure source for transporting liquids and providing chemical reactions. In addition, in many devices, pumps are also used to regulate the temperature. Pump operating principle, construction and classification 1) The working principle can be divided into blade type, volume type and other forms. A vane pump relies on the dynamic action of a rotating impeller on the liquid to continuously transfer energy to the liquid, so that the kinetic energy (main) and pressure energy of the liquid are increased, and then the kinetic energy is converted into pressure energy through the extrusion chamber, and Divided into centrifugal pumps, axial pumps, partial flow pumps and vortex pumps. 2 Positive displacement pump, according to the periodic change of the volume of the sealed working space containing liquid, the energy is periodically transmitted to the liquid, so that the pressure of the liquid is increased to forcibly discharge the liquid, and can be divided into a reciprocating pump according to the movement form of the working element. And rotary pump. 3 other types of pumps that deliver energy in other forms. For example, the jet pump relies on the high-speed injection of the working fluid to draw the fluid to be pumped into the pump and mix it for momentum exchange to transfer energy; the water hammer pump uses a part of the water in the flow when the brake is lifted to a certain height to transfer energy; the electromagnetic pump is The energized liquid metal flows under the action of electromagnetic force to achieve transportation. In addition, the pump can also be classified according to the nature of the liquid to be transported, the driving method, the structure, the use, and the like. 2) Classification by number of working impellers 1 single-stage pump: that is, there is only one impeller on the pump shaft. 2 multi-stage pump: that is, there are two or more impellers on the pump shaft. At this time, the total lift of the pump is the sum of the lifts generated by n impellers. 3) Classification by work pressure 1 low pressure pump: pressure less than 100 meters water column; 2 medium pressure pump: pressure between 100 ~ 650 meters water column; 3 high pressure pump: pressure higher than 650 meters water column. (Multi-stage centrifugal pump up to 2800m) 4) Classification by impeller water intake 1 single-side inlet pump: also called single suction pump, that is, there is only one inlet on the impeller; 2 double-side inlet pump: also called double suction pump, that is, there is a water inlet on both sides of the impeller. It has twice the flow rate of a single-suction pump and can be approximated as two single-suction pump impellers placed back to back together. 5) Classify the 1 horizontal open pump according to the form of the pump casing joint seam: that is, the joint seam is opened on the horizontal plane passing through the shaft line. (The most common horizontal open pump is a double suction pump) 2 vertical joint pump: the joint surface is perpendicular to the axis. 6) Sort the 1 horizontal pump according to the position of the pump shaft: the pump shaft is in the horizontal position. 2 Vertical pump: The pump shaft is in a vertical position. 7) Classification according to the way the water from the impeller leads to the extrusion chamber 1 volute pump: After the water comes out of the impeller, it directly enters the pump casing with a spiral shape. 2 Vane pump: After the water comes out of the impeller, it enters the guide vane set outside it, and then enters the next stage or flows into the outlet pipe. (usually used in multistage pumps and axial pumps) First, the principle of operation An impeller consisting of a number of curved blades is placed within a pump casing having a volute passage. The impeller is fastened to the pump shaft, and the pump shaft is connected to the motor and can be rotated by the motor. The suction port is connected to the suction line at the center of the pump casing, and a Check Valve is installed at the bottom of the suction pipe. The side of the pump casing is a discharge port connected to the discharge pipe and equipped with a regulating valve. Centrifugal pumps are capable of transporting liquids, mainly relying on the centrifugal force generated by the high-speed rotation of the impeller, so it is called a centrifugal pump. The working process of the centrifugal pump: Before pumping, fill the pump with the liquid to be delivered. After the pump is turned on, the pump shaft drives the impeller to rotate at a high speed to generate centrifugal force. Under this action, the liquid is thrown from the center of the impeller to the outer periphery of the impeller, the pressure is increased, and flows into the pump casing at a high speed. In the pump casing, due to the continuous expansion of the flow path, the flow rate of the liquid is slowed down, so that most of the kinetic energy is converted into pressure energy. Finally, the liquid flows from the discharge port to the discharge pipe at a higher static pressure. After the liquid in the pump is thrown, the center of the impeller forms a vacuum. Under the pressure difference between the liquid pressure (atmospheric pressure) and the pressure inside the pump (negative pressure), the liquid enters the pump through the suction line, filling the gap. Remove the location of the liquid. When the centrifugal pump is started, if there is air in the pump casing, since the density of the air is much smaller than the density of the liquid, the centrifugal force generated by the rotation of the impeller is small, and the low pressure generated at the center of the impeller is not enough to cause the vacuum required to suck the liquid. The centrifugal pump will not work. In order to fill the pump with liquid before starting, a check valve is installed at the bottom of the suction pipe. In addition, a regulating valve is also installed on the outlet line of the centrifugal pump for opening the parking and regulating the flow. Second, the basic components and construction 1) Impeller The mechanical energy of the motor is transferred to the liquid to increase the kinetic energy of the liquid. 2) pump casing Collecting liquids as channels for deriving liquids; The energy of the liquid is converted, and a part of the kinetic energy is converted into static pressure energy. 3) Shaft sealing device In order to prevent high pressure liquid from leaking from the inside of the pump casing along the circumference of the shaft, or outside air leaking into the pump casing. Working pressure and seal Packing sealed water pump: maximum working pressure 4-5 bar. (Standard) Mechanically sealed water pump: When the pump has a maximum working pressure <10 bar: unbalanced mechanical seal (standard) When the pump has a maximum working pressure >10 bar: balance mechanical seal (rated value is related to the structure of the seal) Cpvc Pipe,Cpvc Astm Sch80 Pipe,Astm Water Supply Cpvc Pipe,Pressure Cpvc Pipe Milk Yellow Zhejiang Huangyan Minghua Plastic Pipe Fitting CO.,LTD , https://www.pipefitting-mh.com