Development status of stainless steel corrosion-resistant submersible sewage pumps:
Submersible sewage pumps are widely used in municipal engineering, factories, commercial areas, hospitals, hotels, residential areas, etc. for sewage discharge due to their advantages of simple installation, small footprint, easy maintenance, and no noise.
The sewage pumps sold in the market are mostly vertically arranged, with the pump coaxial with the motor, so that the weight of the rotating parts is in the same direction as the water pressure borne by the impeller; Secondly, submersible sewage pumps are used underwater and transport sewage media containing impurities, sludge, and other substances; Thirdly, submersible sewage pumps are a type of centrifugal pump, and their power always increases with the flow rate during operation. When the flow rate exceeds the design flow rate and reaches a certain value, the motor will burn out due to overload.
The reliability of sewage pumps needs to be strengthened, so improving the technical content of their products is the main direction for manufacturers' future development. The submersible sewage pumps in China are mainly produced and manufactured by domestic manufacturers, with a small number of products imported from abroad. Improving the technological content of products and strengthening their market competitiveness can drive the development of the industry. The market prospects for sewage pumps in our country are very broad.
But everything is divided into two parts, and the most critical issue for a sewage pump is reliability, as the pump is used underwater; The medium being transported is a mixture of liquids containing solid materials; The pump is very close to the motor; The pump is arranged vertically, and the weight of the rotating components is in the same direction as the water pressure borne by the impeller. These issues make the requirements for sealing, motor bearing capacity, bearing arrangement, and selection of sewage pumps higher than those of general sewage pumps.
In order to improve the service life of sewage pumps, most manufacturers at home and abroad have found ways to protect the pump system, which can automatically alarm and shut down for maintenance in case of pump leakage, overload, overheating and other faults. But we believe that it is necessary to install a protection system in the sewage pump, which can effectively protect the safe operation of the electric pump. But this is not the key issue, the protection system is just a remedial measure after a pump failure, which is a relatively passive approach. The key to the problem should be to start from the root and thoroughly solve the problems of pump sealing, overload, etc. This is a more proactive approach. To this end, we have applied the hydrodynamic sealing technology of the secondary impeller and the overload free design technology of the pump to the submersible sewage pump, greatly improving the reliability and load-bearing capacity of the pump seal and extending the service life of the pump.

Introduction to corrosion-resistant stainless steel submersible sewage pump:
Submersible sewage pumps are a new generation of pump products that have been successfully developed based on the introduction of advanced foreign technology and the characteristics of domestic water pump usage. They have significant energy-saving effects, anti entanglement, no blockage, automatic installation, and automatic control. It has a unique effect in the discharge of solid particles and long fiber waste.
The QW series submersible sewage pump adopts a unique impeller structure and a new mechanical seal, which can effectively transport media containing solid matter and long fibers. Compared with traditional impellers, the impeller of this pump adopts a single channel or double channel form, which is similar to a curved pipe with the same cross-sectional size and has very good flow characteristics. Coupled with a reasonable volute chamber, the pump has high efficiency and the impeller has undergone dynamic and static balance tests, making the pump operate without vibration.

Characteristics of corrosion-resistant stainless steel submersible sewage pump:
1. Adopting a large channel anti clogging hydraulic component design greatly improves the ability of pollutants to pass through, effectively passing through 5 times the fiber material of the pump diameter and solid particles with a diameter of about 50% of the pump diameter.
2. Reasonable design, reasonable matching motor, high efficiency, significant energy-saving effect.
3. The mechanical seal adopts a dual channel series seal, made of hard and corrosion-resistant tungsten carbide, which has the characteristics of durability and wear resistance, and can ensure the safe and continuous operation of the pump for more than 8000 hours.
4. The pump structure is compact, small in size, easy to move, and easy to install, without the need to build a pump room. It can work by pouring water, greatly reducing project costs.
5. There is an oil-water probe installed in the pump oil chamber. When the mechanical seal on the pump side is damaged and water enters the oil chamber, the probe generates a signal to protect the pump.
6. A fully automatic safety protection control cabinet can be equipped according to user needs to monitor pump leakage, electric leakage, overload, and overheating, ensuring reliable and safe pump operation.
7. The dual rail automatic coupling installation system has brought great convenience to the installation and maintenance of pumps, and people do not have to enter and exit the sewage pit for this.
8. The float switch can automatically control the stop and start of the pump according to the required water level changes, without the need for a dedicated person to supervise.
9. Ensure that the motor operates without overload within the range of head.
10. According to the usage scenario, the motor can adopt a water jacket external circulation cooling system, which can ensure the safe operation of the electric pump in a dry state without water.
11. There are two installation methods: fixed automatic coupling installation and mobile free installation, which can meet different usage scenarios.

Physical picture of stainless steel corrosion-resistant submersible sewage pump product:

WQP stainless steel submersible sewage pump	High flow stainless steel submersible sewage pump

Structural characteristics of corrosion-resistant stainless steel submersible sewage pump:

The WQ type unobstructed submersible sewage pump consists of a motor and a pump, which are separated by an oil isolation chamber and mechanical seal components. It is an electromechanical integrated product, and the motor and pump share the same shaft (rotor). The entire length of the water pump is short and the structure is compact. Equipped with multiple protective devices to ensure safe and reliable operation of the pump. The main functions of its components are as follows:
Signal line 1: Equipped with a fully protected water pump control cabinet to provide * protection for the pump, including leakage, phase failure, short circuit, overheating, motor overload, and other items.
Motor stator 8: adopts B-level or F-level insulation.
Leakage probe 11: This component is installed in the oil chamber. When the mechanical seal is damaged and water enters the oil chamber, the probe can send a signal to the control system to protect the pump.
Mechanical Seal 13: Adopting a dual channel series seal and using a new type of hard and corrosion-resistant tungsten carbide material, it has the characteristics of reliable sealing, wear resistance, and long service life.
Impeller 17: The impeller adopts a single or double channel structure, which has strong passing capacity and can pass large materials and fiber waste, reducing blockage and entanglement failures.
Pump body 15: Paired with the impeller, the pump has high efficiency.
Sealing ring 18: installed at the mouth ring of the pump body. When the impeller wears out the mouth ring due to operation, the sealing ring can be replaced to ensure efficient operation of the pump.

Service conditions for corrosion-resistant submersible sewage pumps:
1. The temperature of the medium should not exceed 60 ℃, the density should be 1.0-1.3kg/dm3, and the pH value should be within the range of 5-14.
2. For pumps without internal self circulating cooling systems, the exposed liquid level of the motor part should not exceed 1/2.
3. In general, pumps must be used within the range of head to ensure that the motor is not overloaded. If it is necessary to use within the full range of head, it should be specified separately when ordering for the manufacturer to manufacture.
During operation, the motor current shall not exceed the rated current of the motor.

Performance parameter table of stainless steel corrosion-resistant submersible sewage pump:

Stainless steel corrosion-resistant submersible sewage pump is mainly used for:
1. The discharge of severely polluted wastewater from factories and businesses.
2. Urban sewage treatment plant drainage system.
3. Sewage drainage stations in residential areas.
4. Civil air defense system drainage station.
5. Wastewater discharge from hospitals and hotels.
6. Municipal engineering and construction sites.
7. Exploration and mining supporting equipment.
8. Rural biogas digesters for farmland irrigation.
9. The water supply system of a water plant.

Precautions for use:
1. The flow rate of the sewage pump should be selected based on the hypothetical second flow rate of domestic livelihood drainage; When there is a regulation of drainage volume, it can be selected according to the maximum hourly flow rate of daily livelihood drainage. The flow rate of the drainage pump in the fire elevator water collection tank shall not be less than 10L/s. The head of the sewage pump shall be calculated and judged based on the lifting height and pipeline loss, and then a certain idle head shall be added. The idle water head should be 0.02~0.03MPa, and the flow velocity of the suction and outlet pipes should not be less than 0.7m/s and should not be greater than 2.0m/s. The flow rate of the sewage pump should be selected based on the hypothetical second flow rate of domestic livelihood drainage;
2. A backup pump should be installed in each living and livelihood drainage collection tank as a unit in public buildings, and it is recommended to operate interactively during normal times. If there are two or more sewage pumps on the floor for flushing drainage in hidden rooms, equipment rooms, and garages, the pumps need not be installed. When the collection tank cannot be equipped with a drainage pipe, the sewage pump should have uninterrupted power supply; When the drainage inlet pipe can be closed, there is no need to set up a discontinuous power supply, but an alarm assembly should be installed. When collecting sewage and wastewater with large impurities, the outlet pipes of the submersible sewage pump in the non collection tank should not be merged and squeezed out; When collecting individual wastewater, it is possible to consider merging and draining the outlet pipes of submersible sewage pumps that do not collect water from the collection tank according to the actual situation. When two or more sewage pumps share the same outlet pipe, valves and check valves should be installed on the outlet pipe of each sewage pump. When a single sewage pump may cause backflow, a check valve should be installed. It is not allowed to merge and displace the pressure drainage valve with the gravity drainage pipe inside the building.
When the submersible sewage pump draws large debris, the submersible sewage pump should be equipped with a crushing assembly; When extracting wastewater containing a large amount of fiber, it is advisable to use a large channel submersible sewage pump. When the power of the submersible sewage pump motor is greater than 7.5kW or the outlet pipe diameter is greater than DN100, a fixed autotransformer device for the water pump can be used; When the power of the submersible sewage pump motor is less than 7.5kW or the outlet pipe diameter is less than DN100, a flexible hose mobile installation can be installed. When using submersible sewage pumps for drainage in sewage collection tanks, a submersible sewage pump fixed self coupling device should be installed to facilitate maintenance of the submersible sewage pump. The submersible sewage pump should be able to start and stop automatically and manually at the incident site. Multiple submersible sewage pumps can operate alternately in parallel or in sections.
4. The drainage pumps used in buildings include submersible sewage pumps, submersible sewage pumps, vertical sewage pumps, and self-priming sewage pumps. Due to the small size of individual sites within the building and the limited drainage capacity, submersible sewage pumps and submersible sewage pumps can be prioritized for drainage. Submersible sewage pumps are generally used in important locations; Vertical sewage pumps and self-priming sewage pumps require seismic isolation foundations, self-priming suction, and occupy a certain amount of space, so they are less commonly used in buildings.

Fault analysis of submersible stainless steel sewage pump: