Characteristics, advantages, disadvantages and wor

2022-07-30
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Characteristics, advantages, disadvantages and working principle of three screw pump. The middle screw is an active screw, which is driven to rotate by the prime mover. The screws on both sides are driven screws, which rotate in reverse with the active screw. The threads of the driving and driven screws are double headed threads

I. characteristics:

★ the spiral sealing line in contact with the stator and rotor completely separates the inlet chamber from the outlet chamber, so that the pump has the function of valve isolation

★ the multiphase mixed transportation of liquid, gas and solid can be realized

★ the volume in the pump does not change when the fluid flows, Without Rayleigh flow agitation and pulse

★ the volume cavity formed by the elastic stator can effectively reduce the wear when transporting the medium containing solid particles

★ the input medium viscosity can reach 50000mpa · s, and the solid content can reach 50%

★ the flow is proportional to the speed. With the help of the governor, the automatic regulating pump can realize positive and negative transportation

II. The three screw pump has the following advantages and disadvantages:

(I): advantages:

1. Compared with the centrifugal pump, the three screw pump does not need to install valves, and the flow is a stable linear flow

2. Compared with the plunger pump, the three screw pump has strong self-priming ability and strong suction height

3. Compared with the diaphragm pump, the three screw pump can transport various media containing mixed impurities, gas, solid particles or fibers, It can also transport all kinds of corrosive substances

4. Compared with gears, three screw pumps can transport substances with high viscosity

5. Different from plunger pumps, diaphragm pumps and gear pumps, three screw pumps can be used for reagent filling and metering

(II): disadvantages:

1. Disadvantages of three screw pumps: high requirements for screw processing and assembly

2. The performance of the pump is sensitive to the viscosity change of the liquid

II. Working principle:

1. Basic working principle of three screw pump: due to the mutual engagement of each screw and the close cooperation between the screw and the inner wall of the liner, one or more sealing spaces will be separated between the suction and discharge ports of the pump. With the rotation and meshing of the screw, these sealing spaces are continuously formed at the suction end of the pump to seal the liquid in the suction chamber, and continuously move from the suction chamber to the discharge end along the axial direction of the screw, so as to continuously discharge the liquid enclosed in each space, just like the case where a nut is continuously pushed forward when the screw rotates. This is the basic working principle of the three screw pump

2. Working principle:

the three screw pump is a propelling positive displacement pump. The main components are the rotor and stator. The rotor is a screw (rotor) with large lead, large tooth height and small screw. The plastic that is not expected to be recycled can only be directly burned or buried. The stator is a matching double helix and screw sleeve. In this way, a space for storing media is formed between the rotor and the stator. When the rotor operates in the stator, The medium moves axially from the suction end to the discharge end

3. The sealing surface between the rod and the shell is a spatial curved surface. There are unsealed areas such as AB or de on this surface, and many triangular notches ABC and def are formed with the groove of the screw. These triangular notches form a liquid channel, which connects the driving screw groove a with the grooves B and C on the driven screw. And the grooves B and C are wound to the back side along their own spiral, and are respectively connected with the grooves D and E on the back side. As there are also triangular gaps similar to the front on the sealing surface where slots D and e connect with slot f (which belongs to the other spiral), a 'the annual output of crude steel, ethylene, cement and 10 kinds of non-ferrous metals is 823million tons, 17.04 million tons, 2.49 billion tons and 44.17 million tons'' B '' C '', so D, F and e will also be connected. In this way, the groove abcdea also forms a ∞ shaped sealing space (if a single head thread is used, the groove will disc the screw along the axial direction and connect the suction and discharge ports, so no seal can be formed). It is not difficult to imagine that many independent ∞ shaped sealing spaces will be formed on such a screw, and the axial length occupied by each sealing space is exactly equal to the lead t of the accumulated rod. Therefore, in order to separate the oil suction and discharge ports of the screw, the length of the screw thread section should be at least greater than one lead

it can be seen from the above working principle that the three screw pump has the following advantages:

1) wide range of pressure and flow. The pressure is about 3 Kilogram force/cm 2, with a flow of 18600cm. Litianhua, the relevant person in charge of the company, told Yangcheng dispatch 3/minute

2) wide range of types and viscosities of transported liquids

3) because the inertia force of the rotating parts in the pump is low, a very high speed can be used

4) good suction performance and self suction ability

5) uniform and continuous flow, small vibration and low noise

6) compared with other rotary pumps, it is less sensitive to incoming gas and dirt

7) solid structure, easy installation and maintenance

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