First, the working principle of vertical centrifugal pump
The mechanical energy of the prime mover is transferred to the liquid by the action of the rotating impeller on the liquid. Due to the action of the centrifugal pump, when the liquid flows from the inlet to the outlet of the impeller, its velocity energy and pressure energy are increased. The liquid discharged by the impeller passes through the pressure chamber, and most of the velocity energy can be converted into pressure energy, and then transported along the discharge pipeline. At this time, a vacuum or low pressure is formed at the inlet of the impeller due to the discharge of the liquid, and the liquid in the suction pool is pressed into the inlet of the impeller under the action of the liquid surface pressure/atmospheric pressure, so the rotating impeller is continuously Aspirating and expelling fluids.
Second, the structure of vertical centrifugal pump
The basic structure of vertical centrifugal pump is vertical structure. The basic structure of a single-stage single-suction vertical centrifugal pump mainly includes a volute-shaped pump casing, a pump shaft, an impeller, a suction pipe, a pressure pipe, a bottom valve, a control valve, a feeding funnel and a pump seat.
1. There are two types of pump casings: axial split and radial split. The casing of most single-stage centrifugal pumps is of the volute type, while the radially split casing of multi-stage centrifugal pumps is usually annular or circular. Typically, the inner cavity of the volute pump housing has a helical flow channel to collect the liquid flowing from the impeller and direct it to the diffuser tube and to the outlet of the vertical centrifugal pump. The pump casing withstands all operating pressures and thermal loads of the liquid.
2. The impeller is the only working component, and the vertical centrifugal pump acts on the liquid through the impeller. Impellers have three types of structures: closed, open and semi-open. The closed impeller consists of blades, front cover and rear cover. The semi-open impeller consists of blades and a back cover. The open impeller has only blades, no front cover and no rear cover. Closed impellers are more efficient, while open impellers are less efficient.
3. The function of the sealing ring is to prevent the internal leakage and external leakage of the vertical centrifugal pump. The sealing ring made of wear-resistant material is inlaid on the front and rear cover rods of the impeller and pump casing, and can be replaced after wear.
4. The impeller is fixed at one end of the pump shaft, and the coupling is installed at this end. Depending on the size of the pump, rolling and plain bearings are available.
5. Shaft seals usually include mechanical seals and packing seals. Typically, vertical centrifugal pumps are designed with both packing and mechanical seals.
Three. Structural characteristics of vertical centrifugal pump
1. The single-stage vertical centrifugal pump is a vertical structure, with the same inlet and outlet diameters and located in the same On the center line, it can be installed in the pipeline like a valve, with compact and beautiful appearance, small footprint and low construction investment.
2. The impeller is directly installed on the elongated shaft of the motor, with short axial dimension and compact structure. It ensures the smooth operation of the pump, low vibration and low noise.
3. The shaft seal adopts mechanical seal or combination of mechanical seals, adopts imported titanium alloy sealing ring, medium-sized high-temperature resistant mechanical seal and adopts cemented carbide material, wear-resistant seal, which can effectively prolong the use of mechanical seal life.
4. Easy installation and maintenance, no need to dismantle the pipeline system. Hydraulic model design is advanced, high efficiency, high energy saving.
5. The internal impeller, pump casing and main parts of the pump are made of stainless steel stamping and forming, the flow channel is particularly smooth, and the bearing bush and bushing are made of hard alloy, which has a super long service life and prevents secondary pollution.
6. Vertical centrifugal pump, used for conveying clean water and other basic liquids with physical and chemical properties similar to clean water, suitable for industrial and urban water supply and drainage, high-rise building pressurized water supply, garden sprinkler irrigation, fire protection increase pressure, long-distance transportation, HVAC refrigeration cycle. Hot and cold water circulation pressurization and equipment for bathrooms, etc., the operating temperature T is less than 80 degrees Celsius.
7. The main control parameters of vertical centrifugal pump are pump flow Q, pump head H, efficiency η, power, speed n, working pressure, necessary cavitation allowance (NPSH) and so on. Vertical centrifugal pumps have a wide range of flow and head. It can be installed in a dry place or immersed in water.
