The action of Metal delivery pump

Metal pump-related:

Melt pump is a high temperature and high viscosity polymer melt transport, pressure and melt metering essential equipment. Melt pump than any other type of pump is compact, reliable operation, low energy consumption, high volumetric efficiency, shear melt small, high pressure in the viscous flow stability, no outlet pressure fluctuations. Unique advantages and the pump has a key role in the process, it has played an irreplaceable role in the polyester production.

First, the structure and working principle

Melt gear pump consists of a pump casing, front and rear side cover, gear shafts, bearings and shaft seal. Melt gear pumps are positive displacement pumps, the working volume changes depend working intermeshing driving and driven gears to convey melt caused. Working volume by the pump, gear and alveolar function has side bearing. When the gear rotates, the melt enters the suction chamber two gear cogging, with the gear, the melt is discharged into the chamber from both sides of the gear again, so that the melt is extruded alveolar discharged chamber pressure to the outlet pipe. As long as the shaft rotates, the gear is sent to the outlet on the pressure side of the melt, and therefore can achieve high pump outlet pressure, flow and discharge pressure basically irrelevant.

High viscosity gear pump gear common with straight teeth, helical, herringbone gear, helical gear, involute tooth profile of the main types of lines and arcs. Gear pumps are usually small and more involute spur gears, gear pumps often used high-temperature shifted gears, transmission of high viscosity, high pressure melt the polymer melt pump to use more involute helical gears. Gear formed integrally with the shaft, its rigidity and higher reliability than a single gear shaft gear pump manufactured. Foreign pressure gear pump gear often uses a square structure, namely the gear tooth width equal to the tip diameter. High viscosity and high pressures using a pump gear teeth of a width less than the diameter of the addendum circle, which is to reduce the radial pressure receiving area of ??the gear, the gear to reduce the bearing load.

Second, the installation and use of a Melt Pump for Extruder.

1. Should carefully open the pump carefully check the packaging, if damaged or missing parts, please get in touch with me. This pump is a high-temperature alloy steel materials, all components are heat-treated high hardness, and therefore more brittle material is a precision device. Any impact and throw touch can cause serious damage, it is recommended mounting rings.

2 Please accurately determine the pump inlet and outlet installation. When properly installed shaft clockwise rotation. When installing the motor, reducer, universal coupling and the pump, the pump must be installed base fixed to ensure concentricity of the pump housing and motor shaft must be no catching rotation, otherwise it will cause the gear stuck, severe shaft fracture.

3 pump pump pressure sensor holes are left appearance and temperature sensor hole, because the sensor is installed correctly, otherwise the deviation of the measured data. Pump connections using high strength (12.9) bolted to ensure safe operation of the pump.

4 just starting the pump should be running at low speed. After the pump is running, such as stability, can gradually adjust to a normal speed and pressure. If pump rotation is not smooth, you must stop the pump to check the reasons, in order to avoid serious damage to the inside of the pump. Case packing seal, closures often adjust the position of the sealing state is always at its best.

Third, melt pump disassembly and cleaning.

1 Carefully pump removed from the device down, placed in a vacuum furnace slowly warming to two hours 400 ℃ -450 ℃. Temperature is not otherwise easily lead to a decline pump overheated material hardness, affect the stability of the pump size.

2 in the process of heating the residue to dissolve the material is discharged. Unscrew the gland in turn, front cover bolts. Demolition of all the parts to keep in mind the position and direction, all homing during installation. When removing the gear due to the residual solid material adhesion, do not knock with a hard object and damaged teeth and bearing edges, but should use plastic or soft copper hammer gently tap to remove it.

3 Remove the pump after the disintegration of the gear and seal assembly should be light on a clean work surface with compressed air or a clean cotton cloth to clean the parts first. And careful examination of the parts for wear, cracks, burrs and scratches. Available attachments 600 # sandpaper lightly sanding the surface, especially when you have to be careful metering gear grinding, plate and D-type bearings, do not go to their metal or grinding them. Otherwise, it will affect the measurement function.

4 After the completion of the various parts polished, cleaned with trichlorethylene or perchlorethylene solvent, and then wipe clean cotton cloth, must not use paper towels, because there may be paper or impurities left on the sticky part, can only be installed after cleaning .

Fourth, the melt pump assembly.

1 jar of oil to prepare before assembly, pump, front cover, the driving and driven gears, each seal before assembly and gland assembly shall be lubricated. Please strictly follow the reverse order of removal of the components installed one by one, so that each part correctly homing assembly.

2 front mounting bolts, use a high-temperature grease to the threaded portion, followed by a diagonal way around the cover and tighten the bolts. The free rotation state can be maintained. If you have any stuck phenomenon can not be strong or turn the pump assembly, such as a properly fitted, the components should be very easy to mount, shaft rotation will be very easy.

Five common faults and countermeasures as follows:

(1) Symptom: The pump can discharge;

Cause Failure: a rotation opposite direction; b suction or discharge valve closed; c entrance no material or pressure is too low; d viscosity is too high, the pump can not bite material..

Strategies: a confirmation direction of rotation; b confirm the valve is closed; c check valves and pressure gauges; d checking fluid viscosity, low speed according to the speed ratio of the flow appears, if traffic flows into inadequate. .. ..

(2) Symptom: insufficient pump flow

Cause Failure: a suction or discharge valve closed; b low inlet pressure; c export pipeline blockage; d stuffing box leakage; e speed is too low. ..

. Strategies:... A confirmation valve is closed; b check valve is open; c confirm excretion is normal; d tightening; leak leak affecting a large number of production should be stopped, demolition inspection; e check the actual shaft speed. ;

(3) Symptoms: abnormal sound

Cause: a large coupling eccentric motor failure or poor lubrication b; c reducer exception; d seal installed at bad; e shaft deformation or abrasion.....

. Strategies: a positive or filled with grease to find; b Check the motor; c check the bearings and gears; d check the seal; e parking disintegration of inspection. ..

(4) Symptoms: excessive current

Cause Failure: a high pressure outlet; b melt viscosity is too large; adverse c seal assembly; d shaft or bearing wear; e motor failure. ..

. Strategies: a check of downstream equipment and piping; b testing viscosity; c inspection seal, appropriate adjustments; d checking hand drive vehicles are too heavy after parking; e check motor. ..

(5) Symptom: pump suddenly stopped

Cause Failure: a power outage; b motor overload protection; c coupling damage; d outlet pressure is too high, interlocking reaction; e pump bite abnormalities; f shaft and bearing adhesive stuck. .. ..

Strategies: a Check the power; b Check the motor; c open safety cover plate car inspection; d checking instruments interlock system; e parking, reversing jigger confirmation; f jigger confirmation. .. ..

Note: The above symptom and countermeasures is one relationship.

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