Daily maintenance and common faults of high temperature unloader
A complete high-temperature unloader includes several parts: motor, reducer, coupling and housing. The head part is composed of housing, front and rear side covers, main shaft, sliding bearing and shaft seal.
A complete high-temperature unloader includes several parts: motor, reducer, coupling and housing. The head part is composed of housing, front and rear side covers, main shaft, sliding bearing and shaft seal. The high-temperature unloader is a positive displacement, and it relies on the change of the working volume caused by the mutual engagement of the main and driven wheels to transport the melt. The working volume is composed of the body, the groove of the sheave and the bearing with the function of the side plate. When rotating, the melt enters the tooth grooves of the two wheels in the suction cavity. As the wheel rotates, the melt is brought into the discharge cavity from both sides, and the wheels mesh again, so that the melt in the tooth groove is squeezed out of the cavity. , Pressure to the outlet pipe. As long as the pump shaft rotates, the wheel pushes the melt to the outlet side, so the outlet can reach a very high pressure, and the flow rate is basically independent of the discharge pressure.
1. Operation management of high temperature unloader
1. Daily maintenance
(1) The disassembly and cleaning of the high-temperature unloader, the temperature rise and fall, and the start and stop operations should be strictly in accordance with the regulations to avoid undue losses.
(2) Attention should be paid to keeping the pressure of the booster population stable, so that it has a stable volumetric efficiency, so as to facilitate its operation and the stability of downstream spinning quality.
(3) For stuffed shaft seal pumps with negative population pressure, the pressure at the stuffing box should be kept higher than the outside atmospheric pressure. When the back pressure is reduced, the pressure of the stuffing box should be adjusted in time, otherwise the pump will suck in air, causing the casting strip to break, affecting the pelletizing, and causing the pelletizer to discharge.
(4) Check the temperature of the heat medium jacket frequently, and keep the heat medium temperature of the main body and the front and back covers consistent.
(5) Every time the output is increased, the current output, speed, outlet, inlet pressure and current value should be recorded, and the data before and after should be compared and analyzed carefully, so as to find abnormalities as soon as possible and deal with them in time.
2. Common faults and countermeasures of high temperature unloader are as follows:
（1) Failure phenomenon: failure to discharge. Reasons for failure: a. The direction of rotation is opposite; b. The suction or discharge valve is closed; c. There is no material at the inlet or the pressure is too low; d. The viscosity is too high and the pump cannot bite. Countermeasures: a. Confirm Rotation direction; b. Confirm whether the valve is closed; c. Check the valve and pressure gauge; d. Check the viscosity of the liquid, whether the flow rate proportional to the speed appears when running at low speed, if there is flow, the inflow is insufficient,
(2) Failure phenomenon: insufficient delivery volume. Causes of failure: a. The suction or discharge valve is closed; b. The inlet pressure is low; c. The outlet pipeline is blocked; d. The stuffing box leaks; e. The speed is too low. Countermeasures: a. Confirm whether the valve Close; b. Check whether the valve is open; c. Confirm whether the discharge volume is normal; d. Tighten; When a large amount of leakage affects production, stop the operation and disassemble for inspection; e. Check the actual speed of the pump shaft;
(3) Failure phenomenon: abnormal sound. Cause of failure: a. Large coupling eccentricity or poor lubrication b. Motor failure; c. Abnormal reduction gear; d. Poor installation of shaft seal; e. Shaft deformation or wear countermeasures: a. Align or fill with grease; b, check the motor; c, check the bearings and gears; d, check the shaft seal; e, check the disassembly of the vehicle
(4) Failure phenomenon: Excessive current. Causes of failure: a. Excessive outlet pressure; b. Excessive melt viscosity; c. Poor shaft packaging; d. Shaft or bearing wear; e. Motor failure countermeasures: a. Check Downstream equipment and pipelines; b. Inspect the viscosity; c. Check the shaft seal and adjust appropriately; d. Check after parking and check whether the hand crank is too heavy; e. Check the motor
(5) Failure phenomenon: Sudden stop failure reasons: a. Power failure; b. Motor overload protection; c. Coupling is damaged; d. Outlet pressure is too high and interlocking reaction; e. Abnormal bite in the pump; f. Shaft Adhesion to the bearing and jamming countermeasures: a. Check the power supply; b. Check the motor; c. Open the safety cover and crank check; d. Check the instrument interlocking system; e. After parking, confirm the cranking in the forward and reverse directions; f. Confirmation description: The above failure phenomena and countermeasures are in a one-to-one relationship. 2. Measures to improve the operating life of the high-temperature unloader. Because the body operates at high temperatures, hinge supports should be installed on the piping during cold installation to prevent piping displacement after heating .