Analysis of the working principle and structure of a three-screw food grade dosing pump

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The primary components that make up the three-screw pump are a bushing (pump cylinder) that is fixed within the pump body, a driving screw that is inserted within the pump cylinder, and two driven screws that mesh with it

The primary components that make up the three-screw pump are a bushing (pump cylinder) that is fixed within the pump body, a driving screw that is inserted within the pump cylinder, and two driven screws that mesh with it. A seal is created between the pump's suction and discharge ports as a result of the three intermeshing screws creating a cavity in the pump cylinder that is sealed off from the outside environment.

Since the two driven screws and the driving screw are symmetrically meshed left and right when the pump is operating, the radial force that is acting on the driving screw is completely balanced, and the driving screw does not bear the bending load. This allows the pump to operate more efficiently. Because the radial force exerted by the driven screw is supported along its entire length by the pump cylinder bushing, there is no requirement for additional bearings to be placed at the outer end of the cylinder, and there is virtually no bending load. During operation, an oil film forms between the outer surface of the screw and the inner wall of the pump cylinder. This oil film has the ability to prevent the metals food grade dosing pump from coming into direct contact with one another and greatly reduce the amount of wear that occurs on the screw tooth surface.

The suction and discharge pressures of the liquid act on the two ends of the screw pump in such a way that the axial thrust is generated on the screw when the pump is in operation. It is possible to use thrust bearings on smaller pumps that have a differential pressure that is lower than 10 kgf/cm2. In addition, high-pressure oil is pumped through the central oil hole of the driving screw and into the bottom of each screw bushing. This creates a balanced thrust that is opposite to the axial thrust at the lower end of the screw, which helps to keep the screw in place.


As is the case with other types of positive displacement pumps, if the pump discharge port is blocked off entirely, the internal pressure of the pump can reach an unsafe level, which can either cause the pump to break or overload the motor. As a result, a safety valve needs to be installed at both the pump's suction and discharge ports. In most cases, a mechanical shaft seal is used for the three-screw pump's shaft seal; however, this seal can be adapted to a variety of configurations depending on the working pressure.

a three-screw pump is characterized by

When the fluid in the pump is active, the volume does not change, and there is no stirring or pulsation of the Rui flow. 4. The volume cavity formed by the elastic stator can effectively reduce the wear when convection is occurring. 1. The spiral sealing line contacting the stator and the rotor completely separates the intake cavity and the discharge cavity, so that the pump has the function of valve isolation. 2. It can realize multiphase mixed transportation of liquid, gas, and solid. 3. It can realize multiphase mixed

5. The input medium viscosity can reach 50,000 MPas, and the solid content can reach 50,000 percent; 6. The flow rate is proportional to the rotational speed, and the automatic adjustment of the volume can be accomplished with the help of the governor.

Both positive and negative directions of movement are possible with the pump.

The following are some of the benefits that come with using a pump with three screws:

1. In contrast to the centrifugal pump, the screw pump does not require the installation of valves, and the flow is a linear movement that is smooth throughout.

2. When compared to the plunger small food grade pump, the screw pump possesses a powerful capacity for self-priming and a strong suction height;

3. In contrast to the diaphragm pump, the screw pump is able to transport a wider variety of mixed impurities, including gas and solid particles or fibers, as well as a wider variety of aggressive substances;

4. When compared to the gear oil pump, the three-screw pump has the ability to transport substances with a high viscosity;

5. Screw pumps, in contrast to plunger pumps, diaphragm pumps, and gear pumps, are suitable for use in the pharmaceutical industry for both filling and metering.

The pump is violently vibrating, the electric rotor may be unbalanced, or the coupling may be poorly combined, and the bearing may be worn and bent; it is also possible that some rotating parts are loose or broken; perhaps the pipeline support is not as strong as it should be, etc. Adjustment, repair, reinforcing, and replacing components, as well as a variety of other strategies, are all viable options.

It is possible that the nut was not tightened sufficiently when it was being installed, which would explain why the pipeline is leaking. Cement or cement slurry that has been mixed with asphalt oil can be applied to the location where there is a leak of air or water if the leak is not too severe. Some damp mud or some gentle soap could be used to make some temporary repairs. In the event that water escapes through the joint, the nut can be tightened by hand. Disassembly is required for significant water loss.


Magnetic pump with overheated packing, primarily as a result of the packing being packed too tightly, the cooling water being unable to enter the packing, or the packing's shaft surface being damaged. Appropriate steps can be taken, such as easing the compression of the packaging and washing the tube food grade stainless steel pumps used for sealing. New packing materials need to be used in place of worn ones. Before installation, it needs to be soaked in oil, then loaded in circles, and the incisions need to be staggered so that there is less chance of water leaking through them. After the final round of packing has been installed, the gland needs to be tightened, and then the level of tightness needs to be adjusted while the machine is running.

The water pump is not able to absorb or drain water for a number of reasons, the most common of which are that the bottom valve is jammed, the water filter is partially clogged, the water absorption height is too high, or the water is leaking. However, the problem could also be the result of improper steering or the obstruction of the impeller flow channel. After each component of the inspection has been successfully completed in turn, subsequent steps, which may include repairing the bottom valve, removing the silt, adjusting the steering, and cleaning the impeller, may then be taken.

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