Shielded pump is shielded motor and mechanical pump combination of mechanical and electrical integration equipment. The so-called shielded motor, is a shield made of non-magnetic material between the stator and the rotor of the motor, the stator and rotor of the motor is divided into two independent spaces that do not communicate with each other. The purpose of doing so is to cancel the mechanical shaft seal (static and dynamic mechanical seal), in order to achieve a completely leak-free effect. Shielded pumps using sliding bearings instead of rolling bearings, and running fluid is filled with the rotor and rotor bearings filled, so no lubrication. Shield pump running smoothly, low noise. Routine maintenance is also rare. As the shielded pump has many irreplaceable advantages in the chemical industry, refrigeration, water supply and drainage, nuclear industry has been widely used. As the number and scope of applications increase, the amount of damage is also gradually increasing. Ammonia refrigeration equipment used in the P1 series shielding pump, for example, introduce maintenance methods. First, the general troubleshooting shield pump very repair 1, the motor winding coil normal resistance; pump can not turn. The reason is dry run caused by the non-liquid operation, the rotor sleeve and the graphite bearing stuck. Or other mechanical failure caused by stuck. Treatment methods, decomposition shield pump, cleaning parts, find the point of failure. Repair or replace parts. 2, the motor is no problem, but the operating current is too large, because the liquid is not enough. Dry grinding situation. Or mechanical debit card and motor cover fastening deviation. Approach. After decomposition. Clean and reassemble. 3, running a lot of noise, the operating current is not stable. The reason is the rotor hub thrust plate and graphite bearings and other serious wear and tear. Disassemble shielded pump. Clean and replace the worn original. Graphite bearing and bearing cover is used between the over-matched, you must heat the bearing cover, to remove or load graphite bearings. Assembly attention should be with the size. Axial stringing momentum (0.5-1.5mm). Warp (0.08-0.12mm), the maximum amount of wear shall not exceed (0.4mm) 4, the motor winding problems, as long as the shield pump motor problems, shielding pump must be overhauled. two. Masking pump overhauls Shield pump overhauls are handled in two separate ways. One is shielding sleeve is not damaged, but the motor problems. The other is the motor and shield are damaged. In either case, the shielded motor housing must be shielded and the motor stator removed for service. For the shielding sleeve is not damaged, the decomposition should try to keep the shielding sleeve intact. To reduce maintenance costs and working hours. 1, the motor stator removal method to disassemble the shield pump, shovel shovel with a flat shovel under the ring weld. With a lathe or cutting machine, cut along the original weld at the motor housing. Fight the positioning point, the motor positioning cover and shield with the hanging out (shield sleeve welding every move). Check whether the motor housing and the stator are equipped with steady nails. if so. Take the nail out. Then heat the motor housing and lift out the stator. (Motor housing and stator, but also the use of over-fitted with). 2, the motor repair shield pump motor difference is not large and ordinary motor, but higher insulation level requirements. H-class motor can be done by the standards. The best choice of QZY series of enameled wire and high temperature insulation materials, in strict accordance with the original motor data offline. To ensure the original motor performance. 3, the production of shielding sleeve Shielding sleeve has been unable to repair, had to re-made. Shielding system is to shield the key to pump maintenance. To choose relatively high nickel content of the corrosion-resistant high-quality stainless steel sheet, the thickness of the original shield to be the same, tailoring size must be accurate.As a very thin shielding, straight welding is its difficulty. If you have the conditions, it is best to use automatic welding machine welding. Manual welding can be done, but higher technical requirements. Make a good shield to round, pressure and leak detection. I use the method is to use nitrogen pressure to 1MPa into the water to observe whether there is leakage. This method is simple and practical. 4, the initial assembly and calibration clean the stator insulation paint and dirt, with a brush inside the brush on the stator a little frozen oil. Press the shield into the stator. Install the upper and lower protective sleeve. Heating the motor housing, press into the stator, into the rotor, installed on the positioning cover and asbestos pad, the rotor hub thrust plate and graphite bearing brush a little frozen oil. Install the upper and lower motor cover and impeller. Adjust, because the motor cover and motor housing has been positioned. Concentricity has no problem, here is to adjust the deviation is around, when the hand wheel has been sliding freely. The motor housing can be welded on the positioning cover with a few positioning. 5, air run test power running. Check the motor's no-load current. Operating noise and stability (time does not exceed three minutes). If there is no problem, you can proceed to the next procedure. 6, welding and repression shielding pump repression. First welding the motor housing and the upper cover of the welding seam. Then weld the upper and lower ring welds of the shield sleeve. A lathe with an inner diameter of less than 0.4mm shield diameter, length 6mm shorter than the shield sleeve as a support sleeve. Push into the shield sleeve, you can suppress the method is filled from the motor inlet at 1.2mpa of nitrogen, will be repaired shield motor leak test into the sink. If there is no leakage within two hours. Can be assembled. Shield pump maintenance is relatively speaking, the technical requirements are relatively high. But just do it carefully. Still can be done.