Vertical axial flow pump characteristics, the basic structure and installation methods

Vertical axial flow pump is a vane pump, this pump has a large flow, low lift, high specific speed, high efficiency, small footprint, variable performance parameters, and suitable for low water conditions and other characteristics. Therefore, it often becomes the preferred type of pump for agricultural irrigation and drainage, urban water supply and drainage, and thermal power plant to transport circulating water. First, the basic structure and role of the water flow from the suction pool, through the inhalation flare tube, impeller impeller impeller forced water rotation, so that water into the guide vane body, the energy conversion to produce head, through the pump cylinder from the drain bend Tube discharge. Pump through the coupling (rigid) and the intermediate shaft coupling. Bearings under the motor bearings bear all the downward axial force of the rotor. Intermediate shaft and motor shaft with a flexible coupling. Axial flow pump impeller (hub body) with blades, according to the blade is adjustable pump performance parameters change, axial flow pump is divided into the following three: Fixed axial flow pump - impeller (hub body) and the blade as a whole structure , The blade is not adjustable; semi-adjustable blade axial pump - impeller (hub body) and the blade as a combined structure only in the shutdown, remove the blade adjustment blade placement angle (such as 0 °, ± 2 °, ± 4 °, ± 6 °, ± 8 °), the adjustment of its angle is a step; Full-blade vane pump - through a set of adjustment mechanism (mechanical or hydraulic), the pump can be used in the operation of manual, electric, computer-controlled And so on, the blade placement angle stepless adjustment. Second, the inflow of water and wet pit, dry pit installation Axial pumps (especially large pumps) on the intake runner type and size requirements are very strict, it directly affects the performance of the pump (such as pump efficiency, cavitation performance, etc.) Therefore must pass the formal design (design institute design). Wet pit installation means that the pump is submerged, in whole or in part, in the liquid being pumped and that the pump is partially submerged in the sump; dry pit installation, which means that the pump is all surrounded by air and is sucked into the pump with an elbow-shaped suction runner . Third, the basic installation of the pump and the discharge outlet elbow position Double-base installation: the pump installed in the foundation, the motor installed in the motor base (on the foundation). The pump axial force is borne by the bearings of the motor bearing. The basic load condition of the pump during operation is as follows: Under the base force = pump shell weight + pump shell water weight - pump axial water thrust motor base force = motor weight + pump rotor Heavy + pump Axial water thrust Single-layer foundation installation: The pump and the motor form an integral direct-connected structure, which is installed on the basis of the motor. The pump shaft and the motor shaft are connected by rigid couplings. Basis (single-layer foundation) Forced = pump shell weight + pump rotor weight + motor weight + pump shell water weight Double base discharge elbows Between the two foundations, the monolayer foundation can be set on top of the foundation as needed. Fourth, the rotor can be withdrawn structure Rotor and pump body is usually "integrated" structure, the entire pump lifting necessary removal, in order to facilitate the maintenance, the rotor can be taken out of the structure. The rotor components (including the guide vanes) are withdrawn from the pump barrel and the discharge elbow, which avoids disassembly of the discharge pipelines and lightens the lifting weight. Fifth, the lubrication of pump-guided bearings and shaft protection Water temperature lubrication, water-lubricated rubber bearings, available transport medium lubrication, pump shaft without protection device, conveying sandy water (such as the Yellow River water) or corrosive media Such as sea water), shaft and guide bearings, the use of protection (sets) of pipe protection, so that the media isolation, with water for lubrication.