Kehai Machinery 1. Several Misunderstandings in Maintenance of Mechanical Seals

The greater the spring compression, the better the sealing effect. In fact, if the spring compression is too large, it will lead to sharp wear and instantaneous burning of friction pairs; excessive compression will make the spring lose the ability to adjust the end face of the moving ring, leading to seal failure.

The tighter the moving ring seal, the better. Actually, too tight dynamic ring seal is harmful. One is to intensify the wear and tear between the seal ring and the sleeve, and leak prematurely; the other is to increase the resistance of the moving ring to adjust and move axially, which can not be adjusted timely when the working conditions change frequently; the third is that the spring is easily damaged due to excessive fatigue; and the fourth is to make the moving ring seal ring deform and affect the sealing effect.

The tighter the static ring seal, the better. Static ring seals are basically in a static state, relatively tight sealing effect will be better, but too tight is harmful. First, it causes excessive deformation of the static ring seal, which affects the sealing effect; second, if the material of the static ring is graphite, it is generally brittle and easily fragmented by excessive force; third, it is difficult to install and disassemble, which easily damages the static ring.

The tighter the impeller lock mother, the better. In mechanical seal leakage, the leakage between sleeve and shaft (inter-shaft leakage) is relatively common. Generally speaking, the leakage between axles is that the impeller lock mother is not locked. In fact, there are many factors leading to the leakage between axles, such as the failure of the pad between axles, offset, impurities between axles, bigger shape and position errors at the joint of axles and bushes, failure of the contact surface, clearance between parts of axles, too long threads of axle heads and so on, which will lead to the leakage between axles. Excessive locking of the lock mother will only lead to premature failure of the inter-axle cushion. On the contrary, proper locking of the lock mother will keep a certain compressive elasticity of the inter-axle cushion. In operation, the lock mother will lock automatically and timely, so that the inter-axle is always in a good sealing state.

The new is better than the old. Relatively speaking, the effect of using the new mechanical seal is better than that of the old one, but the quality or material selection of the new mechanical seal is inappropriate, and the size error of the new mechanical seal will greatly affect the sealing effect; in the aggregate and permeable media, it is better not to replace the static ring if there is no excessive wear and tear. Because the static ring is in a static state for a long time in the static ring seat, the polymer and impurity deposits are integrated and play a better sealing role.

2. In addition to strictly following the instructions for installation and operation, the use of water pumps should also pay attention to two points: Kehai Machinery

One is to avoid relying solely on experience. For example, when the water pump leaks from the bottom valve, some manual drawings are effortless. Before each start-up, fill the inlet pipe with some dry soil, and then rinse the soil to the bottom valve, so that the bottom valve does not leak. This method seems simple and feasible, but it is not good enough. Because when the pump starts to work, sand in the bottom valve will enter the pump with water, wearing impeller, pump shell and shaft, seriously affecting the service life, the correct method should be to repair the bottom valve, which can not be repaired, replaced. The second is to eliminate the faults in time and avoid the "sick" work of the unit. For example, when serious wear of pump shaft packing is found, it is necessary to add packing in time, otherwise the pump shaft packing will leak. The leakage of pump shaft packing not only causes excessive energy consumption of the unit, but also causes cavitation phenomenon, which accelerates the damage of impeller and directly affects the service life of the pump. For example, if the pump is found to be violently vibrating, it should be stopped immediately for inspection, otherwise, if the pump is bent and deformed, there may be a safety accident.

3. Pump units and pipelines should be well maintained after a period of use.

(1) drain the remaining water in the pump and pipeline.

(2) If disassembly is convenient, the pump and pipeline can be disassembled and cleaned up.

(3) Inspection of ball bearings, such as wear and tear of inner and outer sleeves, open, ball wear or surface spots, should be replaced. The bearings can be cleaned with gasoline or kerosene and preserved with butter.

(4) Check whether there are cracks or holes on the impeller, whether the impeller fixed nut is loose, and if there is damage, repair or replace it. Check the clearance at the friction reducing ring of impeller. If the clearance exceeds the specified value, it should be repaired or replaced.

(5) If the pump and pipeline are not dismantled, the outlet shall be sealed with the cover plate to prevent the entry of debris.

(6) When the transmission tape is not in use, the tape should be removed, cleaned and dried with warm water and stored in a place without direct sunlight, and not in a place with oil, corrosion and smoke. Under no circumstances should the tape be stained with oil, diesel or gasoline, and not with rosin or other sticky substances. Before using the tape, the white powder on the contact surface of the tape must be removed.

(7) Clean all screws and bolts with steel wire brush, and coat them with oil or immerse them in diesel oil for preservation.

In short, besides strictly following the instructions, we should also do a good job in pump maintenance and maintenance, so as to prolong the service life of the pump.

4. How long does the grease in the bearing of the pump need to be replaced?

For bearings, lubrication is an important issue that affects their performance. Whether the lubricant or lubrication mode is suitable or not will greatly affect the life of bearings. If the bearing is made of high-grade grease, it can run for 15,000 hours or two years under normal operating conditions. For pumps with motor power greater than 18.5KW or under unfavourable conditions such as high ambient temperature, high air humidity, dusty and highly corrosive industrial environment, bearings should be checked in advance, and lubricating grease should be replaced once every 5000 hours if necessary. The amount of grease filling varies with the structure and volume of the shell. It is generally appropriate to fill up to 1/3-1/2 of the volume. When the filling quantity is too much, the grease will deteriorate, aging and softening due to stirring and heating. Kehai Machinery