Slurry pump auxiliary impeller The difference between water consumption between packing seal and mec

In addition to the auxiliary impeller to play the role of sealing, can also play a role in reducing the axial force, in the mud pump the axial force is mainly composed of the liquid acting on the impeller pressure differential force and the gravity of the whole rotating part, the direction of action of these two forces is the same, the resultant force is formed by the addition of two forces.

It can be seen that under the condition that the performance parameters are exactly the same, the axial force of the mud pump is greater than that of the general horizontal pump, and the difficulty of balancing is more difficult than that of the vertical pump. Therefore, in the submersible sewage pump, the bearing is easy to be damaged, and the reason is also related to the large axial force. If the auxiliary impeller is installed, the direction of the differential pressure force acting on the auxiliary impeller is opposite to the resultant force of the above two forces, which can cancel out part of the axial force, and also plays a role in prolonging the life of the bearing.

However, there is also a disadvantage of using the auxiliary impeller sealing system, that is, a part of the energy is consumed on the auxiliary impeller, which is generally about 3%, but as long as the design is reasonable, this part of the loss can be reduced to a minimum. In the general mud pump, the power always increases with the increase of the flow rate, that is to say, the power curve is a curve that rises with the increase of the flow rate, which will bring a problem to the use of the pump: when the pump is running at the design working point, generally speaking, the power of the pump is less than the rated power of the motor, and the use of this pump is safe; But when the pump head decreases, the flow rate increases (as can be seen from the pump's performance curve) and the power increases.

When the flow rate exceeds the design point flow rate and reaches a certain value, the input power of the pump may exceed the rated power of the motor, causing the motor to overload and burn out. When the motor is overloaded, it either protects the system action and stops the pump from rotating; Either the protection system fails and the motor burns out. The head of the pump is lower than the design working condition point head, which is often encountered in practice, one situation is that when the pump is selected, the head of the mud pump is selected too high, and the pump is used to reduce the head when it is actually used; On the other hand, the working point of the pump is not easy to determine in use, in other words, the flow rate of the pump needs to be adjusted frequently; There is also the case where the pump needs to be used in a frequent change of location.

These three situations may overload the pump and affect the reliability of the pump.

Under normal circumstances, the spacer sleeve of the slurry pump and the impeller are sealed by a sealing ring. A sealing ring is a ring-shaped structure, usually made of rubber or other elastomeric material, that is used to fill between the impeller and spacer sleeve of the pump to prevent leakage of the pump's working medium. The sealing ring can effectively reduce the leakage of the pump, prolong the service life of the pump, and improve the efficiency and reliability of the pump.

At the same time, the sealing ring can also be selected and replaced according to the use environment and medium characteristics of the pump to ensure the normal operation of the pump.

According to the different working conditions of the user. Because each of the three sealing forms has its own advantages and disadvantages.

First of all, packing seal, is the most common kind of seal, which is to continuously inject a certain pressure water into the packing in the form of injecting shaft seal water, so as to prevent the leakage of pump slurry: for multi-stage tandem pumps that are not suitable for impeller shaft seals, packing shaft seals are used. The packing shaft seal has a simple structure, easy maintenance and is cheap.

Secondly, the impeller seal is used by the impeller force of a reverse centrifugal force to prevent the leakage of slurry. When the positive pressure value of the pump inlet is not greater than 10% of the pressure value of the pump outlet, the first-stage pump of the single-stage pump or the multi-stage tandem pump can use the impeller shaft seal, which has the advantages of no shaft seal water, no dilution of slurry, and good sealing effect. Therefore, in cases where dilution is not allowed in the slurry, this type of sealing can be considered.

Thirdly, mechanical seals are generally used when the sealing requirements are relatively high. Especially in some chemical and food fields, not only does it require sealing, but most importantly, it does not allow additional ingredients to enter the pump body. The disadvantages are high cost and difficult maintenance.

In short, the specific choice of which seal depends on the specific customer's industrial and mining conditions. The three sealing forms themselves are good or bad, and it depends on the specific situation of the customer.

Mechanical seal: the sealing performance is the best, but the use requirements are high, the conditions are relatively strict, and the first is also high.