Let me introduce the canned motor pump

1. What is a shielded pump? A shielded pump is a type of centrifugal, seal-less pump. Both the pump and the drive motor are enclosed within a pressure vessel filled with the medium to be pumped. This pressure vessel features only tight seals, and this design eliminates the rotating shaft sealing mechanism found in traditional centrifugal pumps, thereby achieving complete leaklessness. A shielded pump combines the pump and the motor together; the rotor of the motor and the impeller of the pump are mounted on the same shaft. A shielding sleeve is used to separate the motor from the rotor and stator. The rotor rotates within the medium being transported, with power being transmitted to it through the magnetic field of the stator. The rotor that rotates in the liquid and the impeller are mounted on the same shaft, which is supported by bearings at the front and back. Since these bearings are also immersed in the liquid being transported, slide bearings are used in all shielded pumps.

Second, among the domestic manufacturers of shielded pumps, in order of ranking: Dalian Empire, Shanghai Nikkiso, Dalian Hydrotech, Dalian Huanyou, Dalian Sifang……I won’t list the rest. Those whose names are known to everyone can add them; for example, those from Wuxi and Foshan.

Hehe, it’s not simple. I still have more to share; I don’t really like to include long sections of theory… Maybe some people do prefer that. I’ll just provide a link for that later. I still prefer to write down my own personal understanding

III. Which brand of canned pump is the best? There is actually no answer to this question; generally speaking, it’s necessary to analyze the situation based on the specific conditions of the user. I don’t mean to belittle domestic canned pumps, as I’m Chinese myself. But the fact is that companies such as Dalian Empire, Shanghai Nikkiso, and Dalian Haimi have all changed from joint ventures to wholly-owned enterprises. This is a regrettable reality. It’s undeniable that the technologies used by other companies originate from these three companies... If anyone disagrees with this, please avoid arguing here. Dalian Empire has the highest market share in China; its products are widely used, and its product line as well as sales network are well-developed. It belongs to the Japanese technological tradition. Shanghai Nikkiso also falls under the Japanese technological tradition. For some time, Dalian Empire and Shanghai Nikkiso had a certain relationship within Japan. Shanghai Nikkiso entered the Chinese market later than Dalian Empire, but it is also developing rapidly. Dalian Haimi has its own unique style; it seems that no one in China is currently able to imitate its products. It’s quite impressive. Each company has its own characteristics, and whether a pump performs well or not depends on the specific application conditions. However, some companies do have distinct advantages. For example, Shanghai Nikkiso’s sulfur pumps and Dalian Haimi’s liquid chlorine pumps are notable. Among canned pumps, Sifang’s high-temperature resistant pumps also have their own unique features or advantages

IV. Bearings, bearing monitors, and other monitoring devices: Sliding bearings are quite important for shielded pumps. Since it is not possible to observe the operation of the bearings from the outside, this was one of the main reasons why shielded pumps were not widely used in the past. Nisshin Seiki was the first to develop bearing monitors; these were initially mechanical types. Due to their simple structure and low risk of malfunction, they are still in use today. Later on, methods were developed that involved embedding coils inside the motor in order to monitor the operation of the bearings. Examples include Teikoku’s TRG gauge and Nisshin Seiki’s electrical bearing monitor. More recently, both companies have developed newer versions of bearing monitors: Nisshin Seiki’s is an electronic bearing monitor (referred to as E-monitor), while Teikoku’s is the THG (Teikoku Hybrid Guardian) system, which is more advanced. As of now, no one in China has managed to replicate these systems

Could you provide more details on the material of the shielding sleeve? ?

Okay, as suggested by the person above, let’s create a special edition to discuss the materials used for shielding covers. Generally speaking, for low- to medium-power motors, SUS316L is used. Some manufacturers opt for SUS304L. For high-power motors, HC series materials are typically used, as the shielding covers made from these materials help maintain the efficiency of the motor with minimal losses. In some cases, different materials are chosen for the shielding covers of the stator and rotor. For example, the rotor shielding sleeve is made of HC, while the stator shielding sleeve is made of austenitic stainless steel – both choices are aimed at reducing costs. Of course, if the main material used is of high quality, such as HB material used for transporting hydrochloric acid, then the shielding sleeve should also be made of HB material. I remember that for shielding sleeves used in nitric acid under certain conditions, HG material is required

I hope to keep writing, and if anyone from XDJM has any questions, I will answer them one by one. Although shielded pumps are relatively expensive, their leak-free nature means that their use is likely to increase in the future. .

Actually, the selection of material for the shielding sleeve is quite simple. . . There are just a few types, and they are all fixed in place. Inside the shielding pump, the materials that are of utmost importance are those used for the bearings, the shaft sleeves, and the thrust plates

Thank you to the original poster for such a thorough analysis; I’ll ask further if there are still things I don’t understand