The working principle and structure of the canned pump
Leak-free pumps are also required in refrigeration and air-conditioning projects. They have the functions of anti-corrosion and zero leakage. It mainly has canned pump and magnetic pump. They only have static seals and no dynamic seals in structure, so they can guarantee no leakage when transporting liquids.
Structure and working principle of canned pump
The canned pump is also a centrifugal pump. The pump and the drive motor are enclosed in a pressure vessel filled with the pumping medium. The pressure vessel has only a static seal. In the canned pump, the pump and the motor are connected together, the rotor of the motor and the impeller of the pump are fixed on the same shaft, and the rotor of the motor and the stator of the motor are separated by a shielding sleeve. The rotor runs in the conveyed medium, and its power The magnetic field is transmitted to the rotor through the stator. The hydraulic end of the canned pump can be designed and manufactured according to the structural form usually adopted by the general centrifugal pump and the relevant standards and specifications. In addition, an annular gap of about 0.7 mm is provided between the stator and the rotor. When the pump is working, part of the pumped liquid cools the motor through this annular gap, thus solving the problems of easy leakage of the conveying medium, environmental pollution, poor operation reliability, and difficult maintenance caused by the use of mechanical seals in ordinary pipeline electric pumps. This structure cancels the rotary shaft sealing device of the traditional centrifugal pump, and can be completely leak-free. Therefore, the canned pump has a compact structure, less vibration and noise, high pump efficiency, low energy consumption, and no leakage. From the perspective of safety, hygiene and energy saving, for pumping strong corrosive, flammable, explosive or toxic liquids, the selection of canned pumps can achieve satisfactory results.
The main components of the canned pump are impeller, pump shaft, pump casing, bearing seat, circulating pipe, shielding sleeve, motor stator and rotor, etc. Its working principle is similar to that of ordinary centrifugal pumps, the difference is the transmission method of power, that is, the canned pump transmits the torque of the stator to the rotor by the magnetic field.
(1) Sliding bearing
Due to the long rotor, the canned pump needs to be equipped with front and rear sliding bearing seats. These two bearings require precise alignment, and if they are not properly aligned, the bearings are prone to breakage. Because the graphite material is relatively soft, the sliding bearings of the canned pump are mostly made of graphite. The graphite sliding bearing and the surface surfacing of tungsten, chromium, cobalt and other hard alloys or plasma sprayed silicon nitride and other hard alloys form a friction pair, and the service life can reach more than one year.
(2) Shielding sleeve
Canned pumps usually have two shielding sleeves, namely stator shielding sleeves and rotor shielding sleeves. The shielding sleeve is used to prevent the working medium from immersing in the stator coil and the rotor core, and its thickness is generally 0.4 to 0.7 mm. Due to the existence of the shielding sleeve, the gap between the stator and the rotor of the motor is enlarged, which reduces the performance of the shielded motor, and at the same time, eddy currents are generated in the shielding sleeve, which increases the power loss. For canned pumps, the shielding sleeves should be made of non-magnetic materials with good corrosion resistance and high strength. The stator shielding sleeve is preferably Hastelloy. Rotor shields are generally made of Hastelloy or austenitic stainless steel.
Production Application
The company’s main business scope includes: central air-conditioning maintenance, cleaning and technical services; cooling tower and fan coil cleaning and maintenance services; custom processing of lithium bromide solution; sales of lithium bromide solution special impurity separators; central air-conditioning host and various zero Sales of accessories; installation and sales of central air conditioning systems, etc.
Widely used in major air-conditioning systems and process refrigeration cold and heat sources; in steel, textile, chemical, electronics, pharmaceutical, food and other industrial and mining enterprises, as well as hotels, theaters, hospitals, and large commercial buildings , Central heating stations and other occasions are widely used.
Contact Us
Ms. Guo- Sales Support & Operations Manager.
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