Submersible Sewage Pump

Sewage pumps are used more and more widely. From the original simply used to transport water to be able to transport a variety of sewage,such as daily life sewage,industrial sewage,construction site drainage,the liquid feed,etc. It plays a very important role in the municipal engineering ,industry,hospital,construction,hotel,water construction and other industries.

Attentions of submersible sewage pump:

 

(1) When humidity sensor or temperature sensor gives a alarm, or the pump body vibrates during working, or there is abnormal noise, or the water pressure on the output drops, or electricity consumption increased significantly, the submersible sewage pump should be stopped immediately for maintenance.

(2) When some submersible pump without good sealing immersed in the water for a long time, even not start to use, the insulation value will gradually decline, eventually can not be put into use, this declined time is even shorter than the time of submersible sewage pump constantly working in the water and then it has already shown the insulation disappeared. Therefore, the spare submersible pump in the suction tank are not actually effected. If the conditions allowed, put the pump on the shore and keep it dry. When one of sewage water pump in operation has problems, stop it immdiately and raise it up, put the spare pump into the tank.

(3) The submersible pump should not be turned on or off frequently, otherwise the service life of pump will be affected. When the submersible pump stops, the water in the pipeline attacks backflow, if you turn on the pump again that will cause the pump is overloaded, and accept the unnecessary shock loads; if you turn on or off other pumps too frequently, it will damage the parts with poor shock tolerance and bring damage to the whole pump.

(4) When the pump turning off, it can not be re-started till the motor is completely stopped.

(5) Pls cut off the power supply when you check the pump.

(6) During the pump working, do not wash things, or swim, or release livestock into the water in the near, to avoid the electric accident.

 

Characteristics of Zhonglan submersible sewage pump

Adopted advanced technology, strong sewage discharge capacity, no blocking, can effectively pass through solid particles in diameter φ30～φ80mm.

The tearing mechanism can tear and cut off the fibrous materials, and then discharge smoothly, no need to add filter net in the pump.

The design is reasonable, the matching motor power is small, the energy saving effect is remarkable

The mechanical seal with the latest materials can make the pump run safely for more than 8000hours

Compact structure, easy to move, easy to install, can reduce project cost, no need to build pump house

Can be used in the full head range, and that ensure the motor is not overload.

The float switch can automatically control the start and stop of the pump according to the required level change, no need special supervision.

Double guide rail automatic installation system, it brings convenience to installation, people do not have to go in and out the sump.

Equipped automatic protection control box to effectively protect the product from electric leakage, water leakage and overload, improved the safety and reliability of the product.

 

Design technology of Zhonglan sewage sump pump

In the general centrifugal pump, the power always increases with the increase of the flow, that is to say, the power curve is a curve that rises with increase of the flow, which will bring a problem to the use of the pump:

When the pump is running at the operating point, generally speaking, the power of the pump is less than the rated power of the motor, the pump is safe;but as the pump head range decreases, the flow increases(we can see from the pump performance curve), and the power increases.

When the flow exceeds the designed operating point flow and reach a certain data, the input power of the pump may exceed the rated power of the motor,  causing motor to overload and burned.

When the motor is overloaded,either the protection system stops the pump running, or the protection system fails to burn the motor.

The pump head range is lower than the designed working point head, it is often encountered in practice.

One situation is in the selection of pump, the pump head range is selected too high, and the actual use of the pump is to reduce the use of the head range.

Another situation is, the pump operating point is not easy to be determined in the use, in other words, the flow of the pump often need to be adjusted.

There is also a situation where the pump need to be constantly changing the location for use.

These three conditions may make the pump overload and affect the reliability of the pump. So for the pump without full head range(including the sewage pump), its range of use will be limited.

The so-called full head range characteristic(also named no overload characteristic) refers to the fact that the power curve rises very slowly with the increase of the flow rate. Ideally, when the flow increases to a certain value, the power will not rise any more, but will decrease, that is to say, the power curve is a curve with a hump. If so, we just choose the motor rate power point slightly over the hump of power value, so at zero flow to the largest flow of the whole range, no matter you run on which point, the pump power will not exceed the motor power to overload the pump, for the pump with this kind of performance, whether the selection or use, it will be very convenient and reliable.

In addition, the motor power should not be too large, which can save considerable equipment costs.

 

Sealing technology of submersible sewage pump

The so-called assistant impeller hydrodynamic seal refers to an open impeller is installed in the back side of the pump impeller rear cover of the coaxial opposite direction.

When the pump works, the assistant impeller rotates with the pump mainshaft, the liquid in the assistant impeller will rotate together, rotating liquid creates an outward centrifugal force, on one hand,the centrifugal force pushs against the liquid flowing to the mechanical seal, reducing the pressure at the mechanical seal.

On the other hand, solid particles in the medium are prevented from entering the friction joints of the mechanical seal, which reduces the wear of mechanical seal grinding block and extends its service life.

In addition to the sealing role of auxiliary impeller,it can also play a role in reducing the axial force,the axial force of submersible sewage pump is mainly composed of the pressure difference of liquid action on the impeller and the gravity of whole rotating part.The acting direction of the two force is the same,the join force is the sum of the two forces.

It can be seen that under the same performance parameters, the submersible sewage pump force is larger than the general horizontal pump’s, and the balance difficulty is more difficult than the vertical pump’s.

So in the submersible sewage pump, bearing is easy to damage, the reason is also due to the large axial force.

And if we installed the auxiliary impeller, the direction of the pressure difference of liquid action on the assistant impeller is opposite to the above two join forces,  so can offset part of the axial force, also played the role of prolonging the life of the bearing.

But the use of the auxiliary impeller seal system also has a disadvantage, that the assistant impeller will consume part of the energy, generally around 3%, but as long as the design is reasonable,the loss of this part can be reduced to the minimum.

The advantages of Zhonglan sewage pump

Compared with the common horizontal pump or vertical sewage pump, the submersible sewage pump has the following advantages:

1. Compact structure and small floor area. Because The submersible sewage pump works under the liquid, it can be directly installed in the sewage tank, no need to build the pump house to install the pump and the motor, which can save a lot of land and infrastructure costs.

2. Easy installation and maintenance.  Small sewage pump can be installed freely,large sewage pump is generally equipped with automatic coupling device for automatic installation which  is quite convenient.

3. Long running time: because sewage pump and its motor are coaxial, the shaft is short, and the rotating parts are light, the load on the bearing is relatively small, and the life is much longer than the common pump.

4. There are no cavitation damage and water diversion problems, especially the second point brings great convenience to to the operators.

It is because of above advantages that sewage pump has been got more and more people’s attention, it is also being used more and more widely. From the original simply used to transport water to be able to transport a variety of sewage, such as daily life sewage, industrial sewage, construction site drainage, the liquid feed, etc.. It plays a very important role in the municipal engineering, industry, hospital, construction, hotel, water construction and other industries.

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