The sewage pump is a kind of pump type which is connected with the pump and the motor and submerged under the liquid. Compared with the general horizontal pump or the vertical sewage pump, the sewage pump obviously has the following advantages:
1. Compact structure and small footprint. Because the submersible pump works under submerged liquid, it can be installed directly in the lagoon without the need to build a special pump room to install the pump and machine, which can save a lot of land and infrastructure costs.
2. Easy to install and maintain. Small sewage pumps can be installed freely. Large sewage pumps are usually equipped with automatic coupling devices for automatic installation, and installation and maintenance are quite convenient.
3. Continuous operation time is long. Since the sewage pump is coaxial with the pump and the motor, the shaft is short, and the rotating parts are light in weight, 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 water. Especially the latter point brings great convenience to the operator.
5. The vibration noise is small, the motor temperature rises low, and there is no pollution to the environment.
It is precisely because of the above advantages that the sewage pump has been paid more and more attention by people, and the scope of use is becoming wider and wider. It can be used to transport all kinds of domestic sewage, industrial wastewater, construction sites from the original purely used to transport clean water. Drainage, liquid feed, etc. It plays a very important role in various industries such as municipal engineering, industry, hospitals, buildings, restaurants, and water conservancy construction.
But everything is divided into two. The most critical problem for the sewage pump is the reliability problem, because the sewage pump is used under the liquid; the medium to be transported is some mixed liquid containing solid materials; the pump and The motor is placed very close; the pump is arranged vertically, and the weight of the rotating part is in the same direction as the impeller is subjected to water pressure. These problems make the sewage pump have higher requirements in sealing, motor bearing capacity, bearing arrangement and selection than the general sewage pump.
In order to improve the life of the sewage pump, most manufacturers at home and abroad are looking for ways to protect the pump, that is, when the pump is leaking, overloading, over-temperature and other faults, it can automatically alarm and automatically stop the repair. However, 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 to the problem. The protection system is only a remedy after the pump has failed, and it is a relatively passive approach. The key to the problem should be to start from the root and completely solve the problems of the pump in terms of sealing and overloading. This is a more active approach. To this end, we applied the auxiliary impeller fluid dynamic sealing technology and the pump's no-overload design technology to the submersible sewage pump, which greatly improved the pump sealing reliability and load carrying capacity and prolonged the service life of the pump.
First, the application of the sub-impeller fluid dynamic sealing technology The so-called auxiliary impeller hydrodynamic seal refers to the installation of an open impeller in the opposite direction of the coaxial direction near the back of the impeller rear cover of the pump. When the pump is working, the auxiliary impeller rotates with the pump main shaft, and the liquid in the auxiliary impeller rotates together. The rotating liquid generates an outward centrifugal force, which on the one hand bears against the liquid flowing to the mechanical seal and reduces the mechanical force. The pressure at the 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 mechanical seal block and prolongs its service life. In addition to the sealing function, 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 direction of action of the two forces is the same, and the resultant force is the sum of the two forces. It can be seen that in the case of the same performance parameters, the axial force of the submersible pump is larger 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 reason that the bearing is easily damaged is also related to the large axial force. If the auxiliary impeller is installed, the direction of the differential pressure of the liquid acting on the auxiliary impeller is opposite to the resultant force of the above two forces, so that a part of the axial force can be offset, which also plays a role in extending the life of the bearing. However, there is also a disadvantage in 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, the loss can be minimized.
Second, the pump's no-overload design technology in the general centrifugal pump, the power always increases with the increase of flow, that is, the power curve is a curve that rises with the increase of flow, the pump The use poses a problem: when the pump is running at the design operating point, generally, the pump power is less than the rated power of the motor, the use of this pump is safe; but when the pump head is reduced, the flow will increase ( As can be seen from the pump's performance curve, the power is also increased. When the flow rate exceeds the design condition point flow and reaches a certain value, the input power of the pump may exceed the rated power of the motor and cause the motor to be overloaded and burned. When the motor is overloaded, either the protection system acts to stop the pump from rotating; or the protection system fails to burn the motor. The lift of the pump is lower than that of the design working point. It is often encountered in practice. In one case, when the pump is selected, the lift of the pump is too high, and in actual use, the pump is lowered. In the other case, the operating point of the pump is not well determined in use, in other words the pump flow needs to be adjusted frequently; there is also a case where the pump needs to be changed frequently. These three situations may overload the pump and affect the reliability of the pump. It can be said that the range of use of pumps (including sewage pumps) without full lift characteristics is greatly limited. The so-called full head characteristic (also known as no overload characteristic) means that the power curve rises very slowly with increasing flow rate. More ideally, when the flow rate increases to a certain value, the power will not rise any more, but will have some Falling, that is to say, the power curve is a curve with a hump. If so, we only need to select the power rating of the motor slightly more than the power of the hump point, then in the entire range of 0 flow to maximum flow, you are in that one When operating at the operating point, the pump power will not exceed the motor power and the pump will be overloaded. It is very convenient and reliable for the pump with this performance whether it is selected or used. In addition, the motor power does not need to be too large, which can save considerable equipment costs.
1. Compact structure and small footprint. Because the submersible pump works under submerged liquid, it can be installed directly in the lagoon without the need to build a special pump room to install the pump and machine, which can save a lot of land and infrastructure costs.
2. Easy to install and maintain. Small sewage pumps can be installed freely. Large sewage pumps are usually equipped with automatic coupling devices for automatic installation, and installation and maintenance are quite convenient.
3. Continuous operation time is long. Since the sewage pump is coaxial with the pump and the motor, the shaft is short, and the rotating parts are light in weight, 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 water. Especially the latter point brings great convenience to the operator.
5. The vibration noise is small, the motor temperature rises low, and there is no pollution to the environment.
It is precisely because of the above advantages that the sewage pump has been paid more and more attention by people, and the scope of use is becoming wider and wider. It can be used to transport all kinds of domestic sewage, industrial wastewater, construction sites from the original purely used to transport clean water. Drainage, liquid feed, etc. It plays a very important role in various industries such as municipal engineering, industry, hospitals, buildings, restaurants, and water conservancy construction.
But everything is divided into two. The most critical problem for the sewage pump is the reliability problem, because the sewage pump is used under the liquid; the medium to be transported is some mixed liquid containing solid materials; the pump and The motor is placed very close; the pump is arranged vertically, and the weight of the rotating part is in the same direction as the impeller is subjected to water pressure. These problems make the sewage pump have higher requirements in sealing, motor bearing capacity, bearing arrangement and selection than the general sewage pump.
In order to improve the life of the sewage pump, most manufacturers at home and abroad are looking for ways to protect the pump, that is, when the pump is leaking, overloading, over-temperature and other faults, it can automatically alarm and automatically stop the repair. However, 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 to the problem. The protection system is only a remedy after the pump has failed, and it is a relatively passive approach. The key to the problem should be to start from the root and completely solve the problems of the pump in terms of sealing and overloading. This is a more active approach. To this end, we applied the auxiliary impeller fluid dynamic sealing technology and the pump's no-overload design technology to the submersible sewage pump, which greatly improved the pump sealing reliability and load carrying capacity and prolonged the service life of the pump.
First, the application of the sub-impeller fluid dynamic sealing technology The so-called auxiliary impeller hydrodynamic seal refers to the installation of an open impeller in the opposite direction of the coaxial direction near the back of the impeller rear cover of the pump. When the pump is working, the auxiliary impeller rotates with the pump main shaft, and the liquid in the auxiliary impeller rotates together. The rotating liquid generates an outward centrifugal force, which on the one hand bears against the liquid flowing to the mechanical seal and reduces the mechanical force. The pressure at the 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 mechanical seal block and prolongs its service life. In addition to the sealing function, 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 direction of action of the two forces is the same, and the resultant force is the sum of the two forces. It can be seen that in the case of the same performance parameters, the axial force of the submersible pump is larger 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 reason that the bearing is easily damaged is also related to the large axial force. If the auxiliary impeller is installed, the direction of the differential pressure of the liquid acting on the auxiliary impeller is opposite to the resultant force of the above two forces, so that a part of the axial force can be offset, which also plays a role in extending the life of the bearing. However, there is also a disadvantage in 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, the loss can be minimized.
Second, the pump's no-overload design technology in the general centrifugal pump, the power always increases with the increase of flow, that is, the power curve is a curve that rises with the increase of flow, the pump The use poses a problem: when the pump is running at the design operating point, generally, the pump power is less than the rated power of the motor, the use of this pump is safe; but when the pump head is reduced, the flow will increase ( As can be seen from the pump's performance curve, the power is also increased. When the flow rate exceeds the design condition point flow and reaches a certain value, the input power of the pump may exceed the rated power of the motor and cause the motor to be overloaded and burned. When the motor is overloaded, either the protection system acts to stop the pump from rotating; or the protection system fails to burn the motor. The lift of the pump is lower than that of the design working point. It is often encountered in practice. In one case, when the pump is selected, the lift of the pump is too high, and in actual use, the pump is lowered. In the other case, the operating point of the pump is not well determined in use, in other words the pump flow needs to be adjusted frequently; there is also a case where the pump needs to be changed frequently. These three situations may overload the pump and affect the reliability of the pump. It can be said that the range of use of pumps (including sewage pumps) without full lift characteristics is greatly limited. The so-called full head characteristic (also known as no overload characteristic) means that the power curve rises very slowly with increasing flow rate. More ideally, when the flow rate increases to a certain value, the power will not rise any more, but will have some Falling, that is to say, the power curve is a curve with a hump. If so, we only need to select the power rating of the motor slightly more than the power of the hump point, then in the entire range of 0 flow to maximum flow, you are in that one When operating at the operating point, the pump power will not exceed the motor power and the pump will be overloaded. It is very convenient and reliable for the pump with this performance whether it is selected or used. In addition, the motor power does not need to be too large, which can save considerable equipment costs.
Barbecue wire Grill Grate is made of high quality 304 stainless steel, never rusting and durable. BBQ Wire mesh does not have any coating or chemical ingredients, making food safer.
Multi-functional Grill Cooking Grid Grate: This wire mesh is mainly used for BBQ Grill Mat for outdoor cooking, it can also be used as a cooling and baking rack. Or you can develop other uses for it.
BBQ Grate,BBQ Mesh,BBQ Grill, grill grate,grill mesh
Shenzhen Lanejoy Technology Co.,LTD , https://www.brassinsert.net