5 essential common sense for pump maintenance

1. Several mistakes in mechanical seal overhaul

The larger the spring compression the better the seal. In fact, if the spring compression is too large, the friction pair will wear sharply and burn instantly. Excessive compression causes the spring to lose the ability to adjust the end face of the moving ring, leading to seal failure.

The tighter the ring seal, the better. Actually, the sealing ring is too tight and harmful. One is to aggravate the wear between sealing ring and shaft sleeve, premature leakage; Second, it increases the resistance to axial adjustment and movement of the moving ring, which cannot be timely adjusted when the working condition changes frequently. Third, the spring is easy to damage from excessive fatigue; Fourth, make the ring seal ring deformation, affect the sealing effect.

The tighter the static seal ring, the better. Static sealing ring is basically in a static state, relatively close sealing effect will be better, but too tight is also harmful. One is caused by excessive deformation of static ring seal, which affects sealing effect; Second, if the static ring is made of graphite, it is generally brittle, and excessive stress can easily cause fragmentation. Third, installation and disassembly is difficult, easily damage static ring.

The tighter the impeller lock, the better. In mechanical seal leakage, leakage between shaft sleeve and shaft (inter-shaft leakage) is common. It is generally believed that inter-shaft leakage is the mother of the impeller lock. In fact, there are many factors causing inter-shaft leakage, such as inter-shaft pad failure, deviation, impurities between shafts, big configuration error between shafts and bushing, contact surface damage, gaps between components on the shaft, excessive thread length of shaft head, etc., which will lead to inter-shaft leakage. Over-tightening of the locking mother only leads to premature failure of the inter-shaft mat. On the contrary, moderate locking mother keeps the inter-shaft mat compression elasticity at all times. During operation, the locking mother will automatically and timely lock, so that the inter-shaft mat is always in a good sealing state.

The new is better than the old. Relatively speaking, the new mechanical seal is better than the old one, but the quality or material selection of the new mechanical seal is not at the time. In polymer and permeable media, it is better not to replace static rings if there is no excessive wear. Because the static ring is in a static state for a long time in the static ring seat, the polymer and impurity deposition are integrated, playing a better sealing role.

2. In addition to strictly following the installation instructions, two points should be noted:

One is to avoid "experience" alone. For example, when the water pump in the bottom valve leakage, some of the machine hand graph save trouble, in each time starting up, first to the entrance pipe mouth fill some dry earth, and then fill water to flush the earth to the valve, so that the bottom valve does not leak. This method looks simple and easy, but it is not enough. As the sand in the bottom valve will enter the pump with water when the pump begins to work, the impeller, pump shell and shaft will be worn, which will seriously affect the service life. Second, to find fault to remove timely, do not let the unit "disease" work. For example, if the pump shaft packing wear serious, to increase the packing in time, otherwise the pump shaft packing leakage. Pump shaft packing leakage not only causes excessive energy consumption of the unit, but also causes cavitation, which speeds up the impeller damage and directly affects the service life of the pump. For another example, if the pump is found to be vibrating violently, it should be stopped immediately for inspection, otherwise there will be a safety accident if the pump is bent and deformed.

3. The pump unit and pipeline should do well the maintenance of the pump after using for a period of time.

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

(2) if disassembly is convenient, the pump and pipeline can be removed and cleaned up

(3) check the ball bearings, such as inner and outer sleeve wear, open movement, ball wear or surface spots should be replaced. Use gasoline or kerosene to clean the bearings after butter preservation.

(4) check if there is any crack or hole on the impeller, and if the fixed nut of the impeller is loose, repair or replace it if there is any damage. Check the impeller wear ring clearance. If it exceeds the specified value, repair or replace it.

(5) if the pump and pipe are not removed, cover plate shall be used to seal the outlet to prevent the debris from entering

(6) when the transmission tape is not in use, remove the tape, clean it with warm water and wipe it dry, and keep it in a place without direct sunlight. Do not store it in a place with oil, corrosion and smoke. Under no circumstances should the tape be coated with oil, diesel or gasoline, or with rosin or other sticky substances. Before using the tape, remove the white powder from the tape contact surface

(7) wash all screws and bolts with steel wire brush, and apply oil or soak in diesel oil for preservation

In short, in addition to strict accordance with the instruction, should also do a good pump maintenance and maintenance work, so that the service life of the pump can be extended.

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. The proper lubricant or lubrication mode will greatly affect the life of the bearing. If the bearings are using high-grade grease under normal operating conditions can run for 15,000 hours or two years. For pumps with motor power greater than 18.5kw or under adverse conditions such as high ambient temperature, high air humidity, heavy dust and aggressive industrial environment, bearings should be checked in advance, and a replacement of grease can be arranged for 5000 hours if necessary. The filling amount of grease varies with the structure and volume of the casing. Generally, it is advisable to fill up to 1/3-1/2 of the volume. In case of too much filling, the grease will deteriorate, age and soften due to heat of agitation.