Power plants and gear or hydraulic machines that use natural energy to raise water from low to high. Widely used in farmland irrigation, drainage and agriculture, animal husbandry, industrial and mining enterprises, urban water supply, drainage and so on. Pumps used for irrigation and drainage in agriculture and agriculture and animal husbandry are called agricultural pumps and are one of the main components of farmland irrigation and drainage machinery. First, the type according to different working principle can be divided into volume pumps, vane pumps and other types. Volumetric pump is the use of changes in the volume of his studio to transfer energy, there are piston pump, piston pump, gear pump, diaphragm pump, screw pump and other types. Vane pump is the use of rotating blades and water to transfer energy to interact with a centrifugal pump, axial flow pump and mixed flow pump type. Submersible pump pump body part is a vane pump. Other types of pumps have jet pumps, water hammer pumps, internal combustion pumps, respectively, using the principle of jet water hammer and fuel deflagration work. Turbine pump is a combination of turbine and vane pump. The above types of pumps in the following various types of more representative. Centrifugal pump is the use of centrifugal force to increase the pressure of water and make a flow of a pump. By the pump shell, impeller, shaft and other components. The power machine drives the shaft, the shaft drives the impeller to rotate at high speed in the pump shell, and the water in the pump is forced to rotate with the impeller to generate the centrifugal force. Centrifugal forces liquid from the periphery of the impeller thrown into the high-speed high-pressure water flow through the pump casing discharge pump, the impeller center to form a low pressure, which inhale new water flow, constitute a continuous water flow. The impeller has a reverse curved blade rotation direction, the structure of a closed-type, semi-closed and open 3, mostly agricultural impeller closed, both sides of the leaf by the disk closed. The pump body gradually expands into a volute shape along the outlet pipe. Water flow from the impeller side inhaled single suction centrifugal pump, said suction from both sides of the impeller double suction centrifugal pump. In order to increase the lift, multiple impellers can be installed on the same shaft to be multistage centrifugal pumps. The water discharged from the former impeller enters the water inlet of the latter impeller, and then is discharged from the latter impeller after being pressurized, so the more the impeller is, the higher the pressure is. Some centrifugal pumps with automatic removal of suction pipes and pump body air device, without starting the pump before the irrigation, said self-priming centrifugal pump, but its efficiency is often lower than the average centrifugal pump. Centrifugal pumps in agricultural drainage and agriculture and animal husbandry water supply is the most widely used. Used for high lift and flow of small occasions. Single-stage centrifugal pump head is 5 ~ 125 meters, the discharge of uniform flow, usually 6.3 to 400 m 3 / hour, the efficiency of about 86 to 94%. 1. Axial pump pump housing, impeller and shaft and other mechanical components. Also known as propeller pump. The impeller has a number of propeller-like blades. When the impeller is driven by the power machine to rotate together with the rotating shaft, the blades push the water to one end, and at the same time draw water from the water source at the other end to make the water produce a continuous Flow, to achieve the purpose of continuous delivery of water. Flow pressure increases due to impeller rotation. The rotating water flow coming out of the impeller passes through the fixed guide vanes to eliminate the rotational speed and the partial kinetic energy is converted into pressure energy due to the diffusion, so that the water flow in the pump shell rises in the axial direction and flows out of the water outlet pipe. Axial flow pumps are mostly used for low head and large flow occasions, the head range of 1 to 25 meters; flow of 2.7 to 60.0 m 3 / s, the efficiency of up to 85 ~ 90.5%. Vertical, horizontal and inclined installation of three kinds, including vertical axial flow pump more (Figure 2). Large axial flow impeller hub on the propeller blade mounting angle can be adjusted, or by hydraulically powered shaft in operation with time to adjust to meet the head and flow changes require higher productivity, so called adjustable shaft Flow pump. Perfusion pump is a horizontal axial flow pump. Which is composed of a motor, a decelerating device and a water pump, and is arranged in a machine pit inside the underwater embankment. The water inlet and outlet runners are arranged in a straight line with an approximate straight cylindrical shape with less water loss, high water lifting efficiency and compact structure, Easy installation, maintenance, pumping station project is simple. Pump is a kind of low-lift axial pump, in addition to the impeller and its outer casing made of metal material, the inlet and outlet flow channels are used masonry or concrete structure, the lift of 2 meters below the flow Large, simple structure, low cost, high efficiency. Suitable for drainage and irrigation in low-lying areas. 2. Mixed flow pump structure and working principle Centrifugal pump and axial flow pump both types of characteristics of a pump. When the impeller is driven by the power machinery to rotate, the blades push the water body on the one hand and at the same time it drives the water body to rotate to generate the centrifugal effect. Water in the blade thrust and centrifugal force generated by the flow and increase pressure. Flow from the axial flow into the impeller along the blade oblique outflow, commonly used in the delivery of large displacement and medium pressure occasions. There are usually two types of volute and guide vane. The structure of the volute mixed-flow pump is similar to that of the centrifugal pump, and the kinetic energy obtained after the water flows through the impeller is converted into pressure energy by means of the volute-shaped flow passage. In general, the small-medium-sized mixed-flow pump adopts a volute-type structure. Vane-type mixed flow pump, also known as diagonal flow pump, its structure and axial flow pump similar to the smaller radial size, simple and light structure and so on. Large-scale mixed flow pumps are mostly vane-type, and the mounting angle of the blades can generally be adjusted. The flow range of the mixed flow pump is generally 3 to 10.5 meters. The starting power is lower and can adapt to the change of water level. The flow rate is 0.1-50 m 3 / s and the efficiency can reach 64-86%. Since the 1970s, the development of large mixed-flow pumps has been rapid and has replaced the large axial-flow pumps on many occasions. 3. Long axis deep well pump is a vertical single suction centrifugal pump, the impeller installed in the wells below the water level, the power set in the well, through the drive shaft impeller drive in the diversion shell rotation, flow along the guide shell and impeller Between the runner, the water pipe up to the ground. High lift can be used when multiple impeller in series multistage centrifugal pump. Due to the high manufacturing and installation precision of the transmission long axis, the efficiency is significantly reduced with the increase of the well depth, so it is generally only used for deep wells of not more than 100 meters. 4. Submersible pump Pump impeller impeller and drive the motor are dive into the water work of a pump, there are two deep-use and work surfaces. Deep submersible pump through the well into the cable to the motor power, eliminating the transmission shaft, so compact, light weight, easy installation, use and transfer, there is power in the area to replace the long axis deep well pump trend, but Not suitable for wells with high sediment concentration and areas without power supply. Submersible pump motor with dry (motor all sealed), semi-dry (motor stator seal, and the rotor in the water operation), oil-filled (motor oil filled to prevent water invasion into the winding) and wet Water, the stator and the rotor are running in the water) and other types. The first three kinds of need to seal and manufacture and installation of high precision, and thus agricultural deep submersible pumps are usually wet motor, the stator winding using water-insulated wire or stator winding end and groove pouring synthetic resin, water into the motor internal impact Small, sealed structure can be greatly simplified, only requires sand control. Some deep submersible pump head up to 1400 meters, the maximum flow of 1.4 m 3 / s. 5. Jet deep well pump is usually jet pump and centrifugal pump with the corresponding casing composition. Used to lift water from deep wells within 30 meters. The working principle of the jet pump is that the pressure is sprayed through the nozzle to the inlet of the throat pipe. Due to the lateral turbulent diffusion of the jet, the air in the suction pipe is taken away and a vacuum is formed in the pipe. The well water is sucked in and is jetted into the throat Mix, exchange energy. At the outlet of the throat, the velocity of the two flows is close to each other, and most of the kinetic energy is converted into pressure energy through the diffuser tube to further increase the water pressure and finally discharged from the drainage pipe. Jet-type deep well pump has two types of combinations: â‘ jet pump in parallel with the centrifugal pump, the pump through the pipeline pressure water into the jet pump, the jet pump will be part of this water and water to be lifted up together, so that low-flow High pressure water into a large flow of low pressure water, mainly for surface irrigation and channel dredging; â‘¡ jet pump and centrifugal pump in parallel, so that the jet pump to the centrifugal pump pressure to increase its suction, and the centrifugal pump Part of the amount of water provided to the jet pump, the rest into the pressure tank or pressure pipe, the water pressure is high, mainly for irrigation equipment and agriculture and animal husbandry water supply. Compared with the submersible pump and the long axis deep well pump, the jet type deep well pump has the advantages of simple structure
A chlorofluorocarbon (CFC) is an organic compound that contains only carbon, chlorine, and fluorine,
produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as Refrigerants, propellants (in aerosol applications), and solvents. Because CFCs contribute to ozone depletion in the upper atmosphere, the manufacture of such compounds has been phased out under the Montreal Protocol, and they are being replaced with other products such as hydrofluorocarbons (HFCs)[1] (e.g., R-410A) and R-134a.
HCFCs(Chlorofluoromethane)
Foaming Agent Hcfc,Mixed Refrigerant,Air Conditioning Refrigerating,Substitutes Refrigerant
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