Chinese name: rotor pump mbth: rotary pump principle: one or more rotors rotate classification: Features of common gear pumps and screw pumps: Concepts and features: The conveyed materials are stable and undamaged, including gear pumps, external gear pumps, satellite gear pumps, balanced compound gear pumps, non-meshing gear pumps, screw pumps, single screw pumps, twin screw pumps, three screw pump and five screw pumps, but there are many conceptual rotor pumps. Gear pumps and screw pumps are commonly used in chemical plants. The characteristic of rotor pump is 1. The conveying flow can be accurately controlled; The flow of centrifugal pump can't be controlled, and the increase of resistance will lead to the decrease of flow. 2. The conveyed materials are stable, non-destructive and have low rotating speed; The centrifugal pump rotates at a high speed, resulting in impact and bubbles. And the crushing effect. 3. It can transport high-viscosity materials. 4. The pressure head is high, which is suitable for quantitative transportation with long torque and high resistance. 5. Simple structure, easy to fold and clean. Disadvantages: complex manufacturing, high precision and high cost. Ingredients: beverage (condensed milk, syrup, chocolate), fruit concentrate (tomato sauce, jam), paste (minced meat, oil). 5. Rotary pumps: rotor pumps, gear pumps (syrup, grease), vane pumps and screw pumps. Gear Pump External Gear Pump External gear pump is the most widely used gear pump (called ordinary gear pump), and its design and production technology level is also the most mature. Three-piece structure, automatic compensation measures for axial clearance of floating shaft sleeve, radial "hole-sweeping" process of aluminum alloy shell and balance groove are adopted to reduce radial unbalanced force of gears (bearings). The rated pressure of this gear pump can reach 25 MPa. However, due to the small number of teeth of this gear pump, its flow pulsation is large. Satellite gear pump Satellite gear pump (or multi-gear pump, compound gear pump). The structural principle of the satellite gear pump is shown in figure 1. 1 center wheels 1 are installed in the housing 4, and three satellite wheels 5 are evenly distributed around the center wheels. 1 The front end cover 6 is installed in front of the housing, with a liquid inlet on it. 1 The rear end cover 2 is installed at the rear of the housing and is provided with a liquid outlet. The central wheel is supported by two central shaft sleeves 7, and each satellite wheel is supported by two satellite shaft sleeves 3 respectively. When the satellite gear pump works, the power of the prime Mover is input by the central wheel (assuming that the central wheel rotates clockwise), and then the central wheel drives the three satellite wheels to rotate counterclockwise to form three external gear pumps (referred to as sub-pumps). Liquid enters from the liquid inlet of the front end cover, enters the liquid inlet cavities (O 1, O2, O3) of three pairs of meshing gears respectively through the liquid inlet channels, and the pressure liquid is discharged from the liquid outlet cavities (P6) of three pairs of meshing gears. Satellite gear pump balance compound gear pump balance compound gear pump is a new type of hydraulic component (supported by National Natural Science Foundation,No.: 595750 10) proposed by the author based on the combination of planetary transmission theory and gear pump working principle. It retains the advantages of ordinary gear pump and solves the problem of radial hydraulic imbalance of ordinary gear pump. As shown in Figure 2, it is mainly composed of a central wheel, an idler wheel, an internal gear, a sealing block and front and rear pump covers. Due to the symmetry of the structure, the static radial hydraulic pressure on each gear of the pump is completely balanced, forming a compound structure of an external gear pump composed of an intermediate gear 1 and an idler gear 2 and an internal gear pump composed of an idler gear 2 and an internal gear 3, namely a balanced compound gear pump. Balanced compound gear pump Balanced compound gear pump has a series of advantages such as radial hydraulic balance, large flow rate and good flow uniformity. At the same time, due to the balance of radial hydraulic pressure on each gear, the gap between each gear and the pump body can be controlled very small, thus creating conditions for the high pressure of the balanced compound gear pump. The structural principle of non-meshing gear pump is shown in Figure 3. Non-meshing gear pump is mainly composed of input shaft, synchronous gear, diaphragm, oil suction and discharge gear, bearing, pump body and front and rear pump covers. The power of the prime mover is transmitted from the input shaft 1 to the oil suction and discharge gears 7 and 8 through the synchronous gears 2 and 3. Oil suction and discharge gears are respectively sleeved on the input shaft 1 and the transmission shaft 9 through splines. The meshing force of gear transmission is borne by synchronous gear, and the oil suction and discharge gear only bears the hydraulic pressure caused by oil suction and discharge. Screw pump Screw pump depends on the volume change of meshing space to transport fluid. Screw pumps can be divided into single screw pump, double screw pump, three screw pump, four screw pumps and five screw pumps according to the number of screws. Four-screw pump is only produced by a few companies such as American Pyramid, and its characteristics are similar to those of five-screw pump. According to the inhalation mode, it can be divided into single inhalation and double inhalation. According to the number of screw threads, screw pumps are divided into single-head and double-head screw pumps. Double screw pump Single screw pump Single screw pump is mainly composed of screw, pump sleeve and universal coupling. The rotor of a single screw pump is a screw with a circular cross section. On the one hand, it makes planetary motion in a specially shaped bushing (stator), on the other hand, it pushes the liquid to move forward along the internal thread of the stator, constantly moving from the suction chamber to the pressure chamber. The fluid in the chamber flows uniformly along the axial direction without vortex and agitation. Single screw pump is a positive displacement pump with internal meshing seal. Under the same displacement, pressure and rotation speed, the twin-screw pump is smaller and lighter than the single-screw pump. Single screw pump has the advantages of compact structure, small radial size, no pulsation of pressure, no skipping, low noise, strong self-priming performance and small agitation when conveying media. It can be used to transport liquids containing solid particles, acid and alkali salts, liquids with different viscosities, paper pulp, soft green, dirty oil, mud, cement mortar, etc. , widely used in environmental protection, bioengineering, sewage treatment, mining, petrochemical industry, food and sugar production. Kiberg Company of Germany is in the leading position in the world in the design, manufacture, application, performance and efficiency of single screw pump. Twin screw pump Twin screw pump consists of driving screw (main rod), driven screw (driven rod), pump body, safety valve, coupling, filter, synchronous gear and rolling bearing. The two screws (rotors) of the twin screw pump mesh with each other and run in the bushing (stator), and the fluid is sucked and discharged depending on the volume change of the formed sealed cavity. The fluid flows evenly along the axial direction without vortex and agitation. The rotor and stator of double screw pump are made of rigid materials, and its manufacturing accuracy is higher than that of single screw pump. According to the suction mode, twin screw pumps can be divided into single suction type and double suction type. Single-suction twin-screw pump and single-suction five-screw pump should consider the hydraulic balance device to balance the axial force. Double-suction double screw pump, the pump body is equipped with two left-handed and right-handed single-threaded screws, and the axial force on the screws is self-balanced. The master rod drives the slave rod to rotate through the external synchronous gear (external support type). The rotation of the driven rod does not depend on the meshing transmission of the main rod, and the clearance between the two screws and the pump body is guaranteed by gears and bearings. Three screw pump three screw pump is mainly composed of a master rod, two slave rods and a pump sleeve with three screws. The thread of the master rod is convex and the thread of the slave rod is concave, and their spiral directions are opposite. Three screw pump's main rod drives two auxiliary rods through meshing. The three screws (rotors) mesh with each other to run in the inner container, and suck people and discharge fluid depending on the volume change of the formed sealed cavity. The fluid moves axially and uniformly in the pump cavity, without vortex and agitation. The profile of screw pump is usually formed by cycloid, so it is called cycloid meshing screw pump. Three screw pump's meshing clearance is very small, the pressure can reach 25MaP and the noise is low, as high as 57 dB (); High efficiency, especially suitable for high pressure and small flow fluid transportation. Its machining accuracy is higher than that of single screw pump and double screw pump. The disadvantage is that the medium cannot contain solid particles, because the gaps between rotors and between rotors and stators are very small. There are five left and right double-threaded screws in the pump sleeve of the double-suction five-screw pump, and the axial force on the screws is self-balanced. There is involute on the tooth profile of the screw, which plays the role of transmitting motion from the master rod to the slave rod. Rolling bearings are installed at both ends of the screw to ensure the clearance between the screw and the pump sleeve. For single-suction five-screw pump, it is necessary to consider the hydraulic balance device to balance the axial force. Five-screw pump is a kind of unsealed positive displacement pump with low pressure (lower than IMaP). Only used as lubricating oil pump in special occasions with limited installation space (such as ships).