Sealed pumps with magnetic drive

Environmental problems have created and recurrent problems with mechanical seals for sealed pumps for chemical and petrochemical industries, and local companies have to use sealed pumps. One type of narrow pumps-pumps with magnetic drive, which uses magnetic coupling to transfer torque to impeller without the need for mechanical seal.

Magnetic pumps are used in all areas of chemistry and petrochemistry. Considered a piece of specialized equipment, magnetic pumps have been installed under carefully controlled conditions and precautions in their selection and use and have proven highly reliable in comparison to traditional sealed pumps.

This reliability has led to widespread use throughout industry, many times from the time the pump is tight. Known from long life and reliability, but the continuous nature of modern treatment facilities, makes paying attention to use the monitoring requirement. This paper examines the nature of the failures of machines with magnetic drive and recommends appropriate hardware for the different requirements for protection systems installations. Principle of pumps with magnetic coupling to the pump with magnetic drive standard engine uses to control the combination of permanent magnet, which is located on the spindle or the drive unit is located outside of containment.

Magnetic motor mounted on the second shaft, standard motor-driven. The magnetic field rotates the rotor moves the internal procedure. The axial torque synchronous consists of two permanent magnets, magnetic field has been established between the North and South poles of a magnet. This ensures that any sliding or synchronous output torque of the coupling.

The principle of operation of the sealed pumps with magnetic coupling of magnetic field of magnetic driving pump has no connection between drive shaft pump and motor drive. The occupied area is usually mechanical seal or stuffing box, magnetic campaign. Attached to the traditional pump casing is a spiral or cylindrical buffer the envelope sealed by the flat seal to prevent fluid in the environment. The impeller is mounted centrifugal bearings inside the insulating sheath, which also includes the inner circle or stream episode reception.

Outside the shell is rotated external magnetic resonance insulation main engine. Magnetic flux passes through the air gap isolation shell over the interior circle, the outer circle without any physical contact. Insulation or protective sheath prevents leakage to/from the pump system is usually 1.5 mm in thickness and made of high resistance to corrosion. Magnetic drive pump CONSTRUCTION goggles cover-constitutes an obstacle to the pressure, which is installed between the drive and motor magnet. Must contain the working pressure of the pump, because it isolates the pump fluid from the atmosphere. One cup provides better reliability and eliminates the monolithic layers when using two calyx structures.

Since torque magnetic field must pass through the glass, it must be made of non-magnetic materials. Non-magnetic materials such as adding to the alloy or stainless steel, 316SS is traditional glasses. Rotate the Cup in a magnetic field induces eddy currents generate heat must be removed from the recycling process liquid Chamber. Also cause eddy currents, loss of power, which in turn reduces the efficiency of the pump.

Metals with low conductivity are Eddy current, and ensure the best efficiency. In addition to the alloys have relatively low electrical conductivity and good corrosion resistance, so is an excellent option for mineral glasses. Electric conduction materials not connected, such as plastics and ceramics are also a good choice for the glasses, and the loss of Eddy current, completely eliminated. As a result, the efficiency of the pump sealing efficiency pumps. Plastic cups are usually confined to the lower pressures and temperatures due to the strength of plastic. Sleeves and head pumps with magnetic drive system is used to support the internal lubrication of the rotor. These bearings have corrosion properties of the fluid being pumped, therefore, must be made of corrosion resistant materials.

The following properties of the liquid to pump must be taken into account for their impact on the reliability and performance of the pump.

1. Specific heat
2. Viscosity
3. Rate of change in vapour pressure
4. Dissolved gas
5. Flatulence
6. Dirt

Specific heat capacity and coefficient of variation for the steam pressure is important, since the calculation of the thermostat to the internal flow of the pump, to prevent any outbreak within pump when transporting a product. This calculation is performed on the stage of development at the minimum and maximum expected flow conditions. Viscosity-centrifugal pumps magnetic process can be used with high viscosity liquids can exist for limited periods, such as the beginning of the cool in hot oil systems. With the increased viscosity of the efficiency and capacity of the pump is reduced, and documented in accordance with the Institute of hydraulics and documentation.

Manufacturer of friction losses with magnetic drive pumps in the Interior and flow channels increased significantly. The liquids that may be at the beginning of the cold viscosity and initial or soft start heating can be recommending variable speed drive. Dissolved gas-impact of even a small amount of dissolved gas on the performance of centrifugal pump is great. With the exception of some fluid that there is convergence of air or gas tank, the most common cause of diffuse gas. involvement of Vortex flow suction in poorly designed rooms. There are guidelines for dipping or nozzles, as well as helpful in certain cases, change the anti spiral direction of flow. The magnetic drive pump, which depend on the fluid to lubricate the bearings, requires careful design to calculate the fickle and flow naturally.

If the pump is run at extremely low flow-high temperature may be dangerous and the desired height of the liquid column above the pump to port will increase dramatically because of the recycling stream because of the heat. In addition, increasing the load on the bearing with radial pumps with a spiral shape.

If the pump is run at very high flow rate, and the desired height of the liquid above the port to the pump will grow rapidly and could exceed the height of the list then there is cavitation is dangerous. Moreover, the differential pressure of the pump can be lowered to a level is unable to maintain the proper flow of the magnetic coupling, which leads to the instantaneous steam generation procedure. When operating the pump with impeller is too small, it may be the discharge pressure is insufficient to develop the full flow of the composite cooling. By these reasons, there is a safe for all pump design.