Application of melt pump in plastic and chemical industry
MP series of melt pump purpose and features
The melt pump is suitable for the transportation, pressure measurement and measurement of high temperature and high viscosity polymer melt.. The main function of the extruder will be the high temperature melt pressure and constant pressure, and keep the melt flow accurately and stably to feed the extrusion die.. Now melt gear pump has been widely used in chemical fiber, granulation, plastic film, sheet, plate, bar, pipe, wire and cable, drawing, extrusion, composite production line, can process the material covers almost the majority of polymer materials. Such as: PE, PC, PP, PVC, hips, PS, PA, TPUR, containing fluorine polymer, polyester, polysulfone, thermal plastic elastic body, a rubber and thermal adhesive and so on. In chemical fiber, granulation, plastic film, sheet, sheet, material, material, wire, wire, wire drawing, composite extrusion and other production line has been widely used, achieved good results.
Two, application range
(1) for the polymerization process used in the transfer of high viscosity of the melt.
(2), applied to melt spinning, used as a booster pump.
(3) apply to the extruder or injection molding machine to improve the extrusion efficiency and reduce the load of the extruder.
(4) the application of the transfer resin, molten resin, so that the melt is uniform, and the mold head is pressed.
Three, working principle
Belongs to the displacement pump, the work of the main, driven gear meshing with each other caused by the work volume change to transport melt. The volume of work by the pump body, the alveolar gear and bearing sleeve functions with side structure. When the gear rotates, melt into the suction slots in the cavity of the two gears, with the rotation, melt from both sides is brought into the discharge chamber, the gear meshing again, cogging in the melt is extruded and discharge chamber, pressure delivered to the export pipeline. Bearings can't be lubricated with common grease so as to avoid contamination of the melt, usually by melt.
Main effect
1 can achieve stable extrusion, improve the size accuracy of the extrusion products, reduce the scrap rate. In the extrusion process, the material feeding quantity is not uniform, the fluctuation of the cylinder and the head temperature, the pulsation of the screw speed and so on.. Using melt gear pump can eliminate feeding system feeding error can be greatly reduced volatility of upstream technology transfer and quickly enter the stable working state, the higher extrusion product size accuracy, reduce scrap rate. 2 increase output, reduce energy consumption, realize the low temperature, and prolong the life of the machine.. The extruder polymer melt pump is installed, the extrusion machine decompression function to complete the transfer to the gear pump, extruder can work under low pressure and temperature, leakage flow greatly reduced yield. The gear pump is more effective than the extruder to establish the pressure of the die, and can reduce the back pressure of the extruder, so that the axial force of the screw can be reduced, and the service life of the extruder can be prolonged..
3 have linear extrusion characteristics, easy to upstream and downstream - equipment coordination work. Leakage due to the gear pump flow is less, pump power and speed of basic into a linear relationship, after the change of the gear pump speed, the flow can know exactly, as can be determined, the downstream equipment and gear pump synchronous speed, by using the pressure gear pump inlet and the outlet of the acquisition, temperature and other information, to achieve the extrusion process online monitoring and feedback control. It can be applied to high temperature (350 DEG C), high pressure (35MPa), high viscosity (40000000cP) condition;
To pressure and flow pulsation
It has long service life;
To high precision, precise structure.
Main technical parameters:
Output pressure: 35 ~ 0 ~ 70MPa
MP-R series pump suction pressure: vacuum (-0.05 ~ -0.08MPa) ~ 276Bar
Temperature: less than or equal to 350 DEG C
Viscosity of transport medium: 1 ~ 40000Pa.s (1000 ~ 40000000cP)
Heating mode: electric heating or heat conduction oil as well as heat medium heating such as the heating of the gas in the heating of the gas
Driving device: motor + reducer + connection head and universal shaft coupling + + melt pump connection, the motor by ordinary motor, frequency conversion motor, electromagnetic adjustable speed motor or servo motor (customers according to the requirements of working conditions selection)
Flow adjustment: frequency conversion speed control
Installation: can be directly installed in the extruder, or melt pipe
Structure
The melt pump belongs to the volume type gear pump, and uses the external meshing cylindrical gear (spur teeth) to rotate to obtain the accurate fluid volume (mL/r).. The mating surface and the gear tooth surface of the finishing mill can be strictly controlled to assemble the gap to ensure the accurate and stable flow rate, and the influence of the process conditions is not influenced. Especially suitable for conveying high viscosity fluid.
The material rotor is treated by carbon alloy steel, nitriding or die steel, and martensitic stainless steel as a whole quenching, good abrasion resistance (hardness 58-60HRC), and high temperature (350);
The sliding bearing with the mould steel quenching, temperature resistance, wear resistance.
The seal generally uses the packing seal, also may use the mechanical seal.
Drive motor + reducer + universal coupling
The variable frequency speed control, can be adjusted to the required flow.
Heating 1 generally uses electric heating, the pump shell can be directly heated by electric heating rod and electric heating plate.;
2 heat medium heating (for large size pump), the shell with insulation jacket, can control the melt temperature.
The installation of the melt pump with the horizontal input, or upward out of the way, can also be directly installed on the extruder, can also be installed in the melt pipe.