WQ/S Series Chopper Sewage Pump

Submersible sewage pumps have many advantages, the most prominent of which is that they can be used directly in sewage. However, when there is no sewage rack or it is inconvenient to set up a sewage rack, small-diameter submersible sewage pumps often cause the pump and pipeline to be blocked by larger debris in the sewage, causing trouble to users.

In order to solve this headache problem, our company has developed chopper-type submersible sewage pumps with diameters of 50, 65, 80, and 100mm. This type of pump has all the advantages of ordinary submersible sewage pumps, and also has the following unique advantages :

1. It can cut and send objects such as handbags, plastic woven bags, canvas gloves, toilet gloves, cotton woven gloves, daily plastic bags, cloth, toilet paper, sanitary rags, and cotton yarn side by side;

Even objects such as sticks can be easily chopped as long as they can enter through the suction port. It can completely prevent the pump and pipeline from being blocked by debris in the sewage, and there is no need to set up expensive sewage interception and sewage removal devices during use.

2. The impeller and pump cover are made of rust-resistant materials and have been heat treated. The cutting edges on the impeller and pump cover have sufficient hardness and are resistant to rust, so they are extremely wear-resistant and can stay sharp for a long time.
3. The size of the impeller flow channel and the size of the pump body flow channel are accurately matched so that the chopped debris can pass smoothly.
4. The unique arrangement of bearings and mechanical seals makes the cantilever of the shaft very short and the rigidity and strength of the shaft very high. In this way, the vibration of the shaft is very small and the leakage of the mechanical seal is greatly reduced;

The shaft can withstand large impact loads and still has a long life even under heavy-duty operating conditions where the pump occasionally chops harder objects.

5. Both the pump side and the motor side are equipped with mechanical seals to achieve reliable double underwater shaft seal protection of the motor. The oil in the oil chamber fully lubricates and cools the mechanical seal. The mechanical seal area on the pump side has a structure to chop and drive away debris so that debris cannot accumulate or deposit in the mechanical seal cavity, thereby preventing it from affecting the normal operation of the mechanical seal.
6. The scraper grooves set between all current-carrying rotating parts and fixed parts can scrape off the thin and tough debris squeezed between the current-carrying rotating parts and fixed parts.Avoid causing pump power increase or stalling.

The submersible sewage pump is equipped with various motor protection devices. The electric control cabinet of the submersible sewage pump must be matched with these protection devices, and the electric control cabinet of the submersible sewage pump must also be equipped with a float switch that controls the start and stop of the pump based on the liquid level. Therefore, the electric control cabinet of the submersible sewage pump is relatively special and has specific uses. Our company’s special electric control cabinet for submersible sewage pumps is matched with the pump’s protection device, and when the electric control cabinet leaves the factory, it is equipped with a certain number of float switches according to the control method selected by the user, and also has a main circuit It has short circuit, overload, and phase loss protection functions. Electric control cabinets above 15kW also have auto-coupling step-down start or electronic soft start functions. When the main and backup control cabinets are operating normally, the main and backup pump alternation methods include: manual alternation, scheduled automatic alternation (continuous operation), automatic alternation (intermittent operation); in case of failure , all the main and backup control electrical control cabinets have the function of automatically shutting down the faulty pump and automatically putting the backup pump into operation (the backup pump automatically switches on). If the user uses our company’s electric control cabinet but disconnects it from the pump protection device, or the user’s own electric control cabinet does not match the pump’s protection device, or the main circuit short circuit, overload, or phase loss is not set The protection function must not alarm or stop the pump when a fault occurs, so the user does not perform maintenance. The final result is to burn the motor. Therefore, when purchasing a submersible sewage pump, you should purchase a dedicated electric control cabinet for the submersible sewage pump at the same time as much as possible. When purchasing a shredding submersible sewage pump, you should also purchase a dedicated electric control cabinet for the submersible sewage pump.

Nomenclature for control cabinet models of 7.5kW and below

Selection of supporting control cabinet models for 7.5kW and below

Naming method for control cabinet models of 11kW and above

Selection of supporting control cabinet models for 11kW and above

Note: A in the list means automatic alternation or circulation, which can be changed to H to manually select the main and backup pumps.

Note: A in the list means automatic alternation or circulation, which can be changed to H to manually select the main and backup pumps.

Autocoupling step-down starting

It refers to using an autotransformer to reduce the starting voltage applied to the stator winding of the motor when starting the motor. After the motor starts, disconnect the motor from the autotransformer so that it can operate normally under full voltage.

Different taps of the autotransformer can be selected according to the allowed starting current and required starting torque to achieve step-down starting, and it can be used regardless of the Y or △ connection of the stator winding of the motor.

The following table lists the control cabinet model and box size selected for the automatic step-down starting of the submersible sewage pump.

Note: A in the list means automatic alternation or circulation, which can be changed to H to manually select the main and backup pumps.

Note: A in the list means automatic alternation or circulation, which can be changed to H to manually select the main and backup pumps.

Electronic soft start

The soft starter connected in series between the power supply and the controlled motor controls the conduction angle of the internal semiconductor (thyristor), so that the motor input voltage gradually increases from zero according to a preset functional relationship until the end of starting, giving the motor full voltage. . The voltage slowly increases from zero to the rated voltage, so that the starting current of the motor during the starting process changes from the uncontrollable overload impact current to a controllable one, and the starting current can be adjusted as needed.

There is no impact torque during the entire starting process and the motor starts smoothly. Various parameters during the starting process, such as current limit value, starting time, etc., can be adjusted according to the characteristics of the motor load. Soft stop can also be achieved. Due to the use of semiconductor converter technology, high harmonics will be generated, causing pollution to the power grid.

The following table lists the control cabinet model and box size selected for the electronic soft start of the submersible sewage pump.

Terminal boxes and conduits

When the electric control cabinet is far away from the pump room, a terminal box can be installed. The terminal box is an optional accessory.

This picture is for illustration only and does not represent a design specification. Matters regarding pump station design and installation should be handled in accordance with relevant standards and specifications. When it is necessary to install a threading pipe from the terminal box to the electric control cabinet (the threading pipe is prepared by the user), the inner diameter of the threading pipe should be determined according to the outer diameter of the cable, and note: the inner diameter of the threading pipe at the corner should be large enough, and the diameter of the threading pipe should be large enough. The bending radius should also be large enough. If our company’s special cable for submersible sewage pump is used from the terminal box to the electric control cabinet, the outer diameter of the cable is as shown in the table below:

In order to achieve reliable protection of the submersible motor, our WQ/S series chopper-type submersible sewage pumps use O-ring seals to achieve static sealing, and two sets of independent mechanical seals to achieve double dynamic sealing of the shaft. The friction pair of the mechanical seal on the pump side that is in contact with the water, that is, the first shaft seal of the motor, is silicon carbide-silicon carbide or silicon carbide-tungsten carbide, which has extremely high hardness and is very wear-resistant.

The friction pair uses the oil in the oil chamber for cooling and lubrication; the mechanical seal on the motor side, which is the second shaft seal of the motor, is completely inside the oil chamber and does not come into contact with dirt and impurities under normal circumstances, so the operating conditions are more superior. , the friction pair uses graphite-silicon carbide pairing with a very low friction coefficient, and has a long service life.

However, no matter how good the mechanical seal is, there will inevitably be slight leakage. To ensure the high reliability of the motor, a leakage probe is installed in the oil chamber.

The leads of the two electrodes of the water leakage probe are connected to the special electric control cabinet of the submersible sewage pump through cables. When the pump has been running for a long time and the water leaked from the mechanical seal on the pump side into the oil chamber reaches a certain level,

The water leakage probe can alarm through the electric control cabinet (the indicator light is on), reminding the operator to change the oil, so that both sets of mechanical seals can return to normal operating conditions;

If the alarm occurs frequently, the operator can perform maintenance. A leakage probe is also installed on the lower side of the motor cavity. The lead of the leakage probe is connected to the special electric control cabinet for the submersible sewage pump through a cable. Once the liquid leaking from the mechanical seal on the motor side enters the leakage probe cavity,

The water leakage probe can alarm (the indicator light is on) and stop the pump through the electric control cabinet, prompting the operator to perform timely maintenance. During maintenance, not only the mechanical seal must be repaired, but also the insulation of the motor should be checked.

A thermal element is embedded in each of the three windings of the motor. The three thermal elements are connected in series and connected to the cable and the special electric control cabinet for the submersible sewage pump through two wires. Under abnormal operating conditions,

When the winding temperature reaches the set value, any action of any of the three components will cause an alarm (indicator light turns on) through the dedicated electric control cabinet of the submersible sewage pump and stop the pump to protect the winding from overheating. Since only one of the three thermal components is effective, it will play a protective role, and the probability of all three components failing is extremely low, so the reliability of winding overheating protection is extremely high.

The protection of the motor in the event of short circuit, phase loss, and overload is a must-have function for any electric control cabinet, and of course it is also a function of the special electric control cabinet for submersible sewage pumps. It should be pointed out that phase loss is the biggest killer of motors. Without a good electrical control cabinet, it is impossible to prevent the motor from burning due to phase loss.

As for just using the gate switch, for three-phase motors, it is a method that fails but fails. The leakage protection components and thermal components installed in the pump cannot function without the dedicated electric control cabinet for submersible sewage pumps. The electric control cabinet can also realize unattended and automatic control.

Therefore, for submersible sewage pumps, since their working environment is harsher than that of ordinary pumps, it is very necessary to configure a special electric control cabinet for submersible sewage pumps;

As for the shredder-type submersible sewage pump, its working environment is harsher than that of general submersible sewage pumps, so it should be equipped with a dedicated electric control cabinet for submersible sewage pumps.

For example, when encountering debris that is difficult to cut and causing stalling (commonly known as “stuffing”), if a dedicated electric control cabinet for the submersible sewage pump is not configured, the motor will burn out;

If configured, the circuit breaker or thermal relay in the cabinet will automatically cut off power and shut down, prompting users to check and eliminate problems to avoid burning the motor.

Our company’s special electric control cabinet for submersible sewage pumps is equipped with a certain number of float switches according to the number of control pumps.

When the electric control cabinet is set to the automatic control position, the start and stop of the pump can be controlled through the float switch according to the level of the liquid level. The minimum liquid level is set to ensure the heat dissipation of the motor when it runs continuously for a long time, and to prevent the pump from inhaling air to produce vibration, noise, or even induce cavitation and damage the impeller.

List of motor protection components installed in the pump:

List of motor protection devices installed in the electric control cabinet:

1. In order to make the pump you choose more suitable, users are warmly welcome to consult the submersible sewage pump unit of our company’s technical center for technical issues.
2. When ordering, please indicate the pump model (including installation method) according to the “Model Description” in the “Technical Description” above.
3. All cutter-type submersible sewage pumps can be installed with automatic coupling or a vertical base connected to hard pipes or hoses.
4. In general, the standard cable for water pump motor is provided at 10 meters. If users require other lengths, they should indicate this when ordering.
5. The “complete supply” parts in the “Supply List” mentioned later are supplied according to the installation method selected by the user.

“Supply according to the purchase requirements of the order” items are ordered separately by users according to their own needs. What needs special explanation is:

The guide rod in the coupling device only needs to be cut to the required length using ordinary water pipes or steel pipes, and no other processing is required. We have noted the specifications and length calculation formulas and data of the water pipe or steel pipe used as the guide rod in the automatic coupling installation size chart of each pump in the sample.

Users only need to purchase water pipes or steel pipes, cut them to the required length, and then use them. Because it is easy to prepare but inconvenient to transport, the coupling device provided by our company does not include guide rods. If you need our company to supply guide rods, you must order them separately.