Submersible Sewage Pump

Main Uses

① Discharge of wastewater from enterprise units.
② Urban sewage treatment plant discharge system.
③ Subway, basement, civil air defense system drainage station.
④Sewage discharge from hospitals, hotels, and high-rise buildings.
⑤ Sewage drainage station in the residential area.
⑥ Municipal engineering, discharge of thin mud in construction sites.
⑦Water supply device of waterworks.
⑧ Sewage discharge from farms and irrigation of rural farmland.
⑨ Exploration mines and water treatment equipment.
⑩ Instead of manual work, the river mud is sucked and transported.

Conditions of use Water temperature≤60℃, liquid PH value is 4～10.
 

Scope of Application

Discharge of polluted wastewater from factories and businesses.
Urban sewage treatment plant drainage system.
A sewage discharge station in a residential area.
Civil air defense system drainage station.
Sewage discharge from hospitals and hotels.
Municipal works, construction sites.
Exploration and mining supporting machines.
Rural biogas digesters, farmland irrigation
 

Features

Using advanced technology, it has a strong sewage discharge capacity, no blockage, and can effectively pass through solid particles with a diameter of φ30-φ80 mm.

The impeller with a cutting function can tear the fibrous material, cut it, and then discharge it smoothly without adding a filter screen to the pump.

The design is reasonable, the supporting motor power is small, and the energy-saving effect is remarkable.

The mechanical seal of the latest material can make the submersible sewage pump run safely and continuously for more than 8000 hours.

The structure is compact, easy to move, and easy to install, which can reduce engineering costs and eliminate the need to build a pump room.

It can be used in the full head range without overloading the motor.

The float switch can automatically control the start and stop of the submersible sewage pump according to the required water level changes, without the need for specialized personnel.

Double guide rail automatic installation system, the submersible sewage pump can be lifted out during installation and maintenance, which is very convenient.

Equipped with an automatic protection control box, it can effectively protect against the leakage of electricity, water, and overload of the submersible sewage pump, and improve the safety and reliability of the product.

Advantage

Compared with the general horizontal pump or vertical sewage pump, the submersible sewage pump has obvious advantages in the following aspects:

1.Compact structure and small footprint. Because the submersible sewage pump works submerged in the liquid, it can be directly installed in the sewage pool, and there is no need to build a special pump room to install the pump and the machine, which can save a lot of land and infrastructure costs.
2.Easy installation and maintenance. Small sewage pumps can be installed freely, and large sewage pumps are generally equipped with an automatic coupling device for automatic installation, which is very convenient for installation and maintenance.
3.Long continuous operation time. Because the pump and the motor are coaxial, the shaft of the submersible sewage pump is short, and the rotating parts are light in weight, so the load (radial) on the bearing is relatively small, and the service life is much longer than that of the general pump.
4.There are no problems such as cavitation damage and irrigation and water diversion. Especially the latter point brings great convenience to the operator.
It is precise because of the above advantages that the submersible sewage pump has been paid more and more attention by people, and the scope of use has become wider and wider. , liquid feed, etc. It plays a very important role in municipal engineering, industry, hospital, construction, restaurant, water conservancy construction, and other industries.
 

Disadvantages

For the submersible sewage pump, reliability is the most critical issue, because the sewage pump is used in the liquid, the conveyed medium is some mixed liquid containing solid or fibrous impurities, the motor is inside the pump body, and the pump is Vertical arrangement, the weight of the moving parts and the water pressure of the impeller are in the same direction.

These problems make the submersible sewage pump have higher requirements than the general sewage pump in terms of sealing, motor carrying capacity, bearing arrangement, and material selection.
 

Research and Development

In order to improve the lives of the submersible sewage pump, Tuohai Pump Industry Co., Ltd is constantly improving the protection system of the pump, that is, it can automatically alarm when the submersible sewage pump is leaking, overloaded, over-temperature, and other faults, and automatically shut down for repair.

In addition, we believe that it is necessary to set up a protection system in the submersible sewage pump, which can effectively protect the safe operation of the pump. But this is not the crux of the problem, the protection system is just a remedy after the pump fails, it is a more passive method. The key to the problem should be to start from the root and completely solve the problems of the submersible sewage pump in terms of sealing and overloading. This is a more active method.

For this reason, we apply the auxiliary impeller hydrodynamic sealing technology and the non-overload design technology of the pump to the submersible sewage pump, which greatly improves the reliability and bearing capacity of the pump seal and prolongs the service life of the pump.
 

Sealing Technology

The so-called auxiliary impeller hydrodynamic seal refers to the installation of an open impeller in the opposite direction coaxially near the back of the back cover of the impeller of the pump.

When the pump is working, the auxiliary impeller rotates with the main shaft of the pump, and the liquid in it also rotates together, thereby generating an outward centrifugal force. On the one hand, this centrifugal force resists the liquid flowing to the mechanical seal and reduces the pressure at the mechanical seal.

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

In addition to the role of sealing, the auxiliary impeller can also reduce the axial force. In the submersible sewage pump, the axial force is mainly composed of the differential pressure force of the liquid acting on the impeller and the gravity of the entire rotating part. The two forces act in the same direction, and the two forces add up to form an axial force.

It can be seen that under the same performance parameters, the axial force of the submersible sewage pump is larger than that of the general horizontal pump, and the balance difficulty is more difficult than that of the vertical pump.
Therefore, in the submersible sewage pump, the reason why the bearing is easily damaged is also closely related to the large axial force.

If the auxiliary impeller is installed, the direction of the pressure differential forces acting on the auxiliary impeller is opposite to the resultant force of the above two forces, which can offset part of the axial force and prolong the bearing life.
However, the use of the auxiliary impeller sealing system also has a disadvantage, that is, a part of the energy is consumed on the auxiliary impeller, generally about 3%, but as long as the design is reasonable, this part of the loss can be reduced to a minimum.
 

Design Technology

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

When the pump is running at the design operating point, the pump will operate safely at a power less than the rated power of the motor. But when the head is reduced, the flow rate increases (as can be seen from the pump performance curve) and the power also increases.

When the flow exceeds the design operating point flow and reaches a certain value, the input power of the submersible sewage pump may exceed the rated power of the motor, causing the motor to be overloaded and burned.

When the motor is overloaded, either the protection system acts to stop the pump, or the protection system fails, and the motor burns.

It is often encountered in practice that the head of the pump is lower than the head of the design operating point.

E.g:

When choosing the model of the submersible sewage pump, the pump lift is too high, but the actual lift is lower than the pump lift in actual use.

The working point of the pump in use is not very well determined. In other words, the flow rate of the pump needs to be adjusted frequently.

There is also a situation where the pump needs to be used frequently in different locations.

All of these three situations may overload the pump and affect its reliability of the pump. It can be said that for pumps without full-lift characteristics (including submersible sewage pumps), the scope of use will be greatly limited.

The so-called full-head characteristic (also called the no-overload characteristic) means that the power curve rises very slowly with the increase of the flow rate. More ideally, when the flow rate increases to a certain value, the power will not rise anymore but will be dropped. That is to say, the power curve is a curve with a hump. If this is the case, we only need to select the power value where the rated power of the motor slightly exceeds the hump point, then in the entire range from 0 flow to the maximum flow, no matter which operating point The power of the submersible sewage pump will not exceed the power of the motor to overload the pump. For the pump with this performance, it will be very convenient and reliable when used.

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

Use

Drainage pumps used in buildings include submersible sewage pumps, submerged drainage pumps, vertical sewage pumps, and horizontal sewage pumps. Since the general site in the building is small and the drainage volume is not large, the drainage pump can preferably be a submersible sewage pump. Vertical sewage pumps and horizontal sewage pumps require seismic isolation foundations, and self-irrigation water absorption, and occupy a certain site, so they are less used in buildings.

The flow rate of the submersible sewage pump should be selected according to the design second flow rate of domestic drainage:

When there is drainage adjustment, it can be selected according to the maximum flow of domestic drainage. The flow rate of the drainage pump in the fire-fighting elevator sump shall not be less than 10L/s. The head of the drainage pump is determined according to the lifting height and pipeline loss, and then a certain free head is added. The free water head should be 0.02～0.03MPa. The flow velocity of the water inlet and outlet of the submersible sewage pump should not be less than 0.7m/s, and should not be greater than 2.0m/s.

In public buildings, a spare pump should be set up in each living drainage sump as a unit, and it should be operated interactively at ordinary times. For the drainage of the basement, equipment room, and garage flushing the ground, if there are two or more drainage pumps, the pump may not be used.

When the sump cannot be equipped with an accident drainage pipe, the pump should have an uninterrupted power supply.

When the drainage and water inlet pipes can be closed, the uninterrupted power supply may not be provided, but an alarm device should be provided.

When lifting sewage and wastewater with large impurities, the outlet pipes of submersible sewage pumps in different sumps should not be discharged together.

When lifting general wastewater, the outlet pipes of submersible sewage pumps in different sumps can be considered together for discharge according to the actual situation. When two or more pumps share one outlet pipe, a valve and a check valve should be installed on the outlet pipe of each pump. When the drainage of a single pump may cause backflow, a check valve should be installed. It is not allowed to combine the pressure drainage switch with the gravity drainage pipe in the building.

When the submersible sewage pump lifts sewage containing large debris or more fibers, the submersible sewage pump should be equipped with a crushing device or a cutting-type submersible sewage pump, and a large-channel submersible sewage pump should be used.

When the motor power is greater than or equal to 7.5kW or the diameter of the water outlet is greater than or equal to DN100, the submersible sewage pump can be installed with an auto-coupling device. When the motor power of the submersible sewage pump is less than 7.5kW or the diameter of the water outlet is less than DN100, a flexible hose can be installed. When the sewage collection tank is drained by a submersible sewage pump, an auto-coupling device for fixing the water pump shall be provided to facilitate the maintenance of the water pump. The drainage pump should be able to automatically start and stop and manually start and stop on-site. Multiple pumps can be operated alternately in parallel, and can also be put into operation in sections.
 

Announcements

When the humidity sensor or temperature sensor issues an alarm, the pump body of the submersible sewage pump vibrates, the noise is abnormal, or the output water pressure drops, and the power consumption increases significantly, the submersible sewage pump should be stopped immediately for maintenance. 

When some submersible sewage pumps with poor sealing are immersed in water for a long time, even if they are not used, the insulation value will gradually decrease, and eventually, they cannot be used. Therefore, when the submersible sewage pump is on standby underwater, it may not function as a backup. If conditions permit, it can be placed in a dry place outside the pool or in a warehouse for standby. When a submersible sewage pump in operation fails, it must be shut down and lifted up immediately, then put the backup pump down. 

The submersible sewage pump cannot be opened and stopped too frequently, otherwise, the service life of the pump will be affected. When the submersible sewage pump stops, the water in the pipeline will return, and starting at this time will cause the electric pump to be overloaded when it starts, and bear the impact load of the return flow. In addition, if the submersible sewage pump is started and stopped too frequently, it will damage the parts with poor impact resistance, thereby damaging the entire submersible sewage pump. 

After stopping, it cannot be restarted until the motor has completely stopped running. 

The power must be cut off when checking the submersible sewage pump. 

When the submersible sewage pump is working, it should not touch the nearby water body to avoid the electric shock accident when the pump leakage.

TAIXING TUOHAI PUMP INDUSTRY CO., LTD