What is molten salt submerged pump

RY-type molten salt pump is a single-stage, single-suction cantilever submerged pump, which is suitable for conveying molten salt (KNO3 53%, Na2NO240%, NaNO37%) with high temperature (temperature ≤ 600 ℃), for industrial departments such as ionic membrane caustic soda, alumina, etc., and also for conveying liquid with other high-temperature special media. RY-type molten salt pump is a series of molten salt pump products independently developed on the basis of years of production of high-temperature submerged pump and molten salt submerged pump, referring to the structure of similar foreign products. It is a special high-temperature pump for molten salt circulation system or molten salt transportation.
The structure of molten salt pump mainly consists of power system, transmission system and conveying system. The power system mainly includes motor and motor support. It is the power source of molten salt pump. The transmission system includes the main shaft and bearing bracket, which is responsible for completing the power transmission. The high-speed operation of the motor is converted into the operation of the impeller to generate the power to transport high-temperature molten salt. The conveying system is mainly composed of conveying pipes, which is used to complete the transportation of high-temperature molten salt.
Before determining the type selection of molten salt pump, the composition of molten salt used should be analyzed first. Including the type of molten salt, service temperature, melting point, gasification point, etc. On the whole, the material of the pump should be resistant to high temperature and corrosion, and its strength and service life should be considered. The gas released by molten salt decomposition at high temperature is more corrosive. Taking the common binary molten salt as an example, the operating temperature of the trough molten salt power station and the tower molten salt power station are different. The operating temperature of the trough molten salt heat storage system is between 220 ℃ and 400 ℃. According to this temperature, 304 and 316 stainless steel can be selected as the material of the molten salt pump; For tower type molten salt power station, the working temperature of molten salt is between 220 ℃ and 550 ℃, and 316, 347 stainless steel or 718 chromium-nickel alloy steel that is more resistant to high temperature and corrosion is  required.
The high-speed flow of molten salt will also cause rapid corrosion of the impeller blades of the molten salt pump. The corrosion damage rate is proportional to the medium flow rate. The higher the flow rate, the faster the corrosion rate. Therefore, the flow rate of molten salt should be properly controlled within the safe range.

Take you to understand the use of vacuum pump filter

15 problems in daily maintenance of centrifugal pump


The centrifugal pump works by centrifugal movement of water when the impeller rotates. Before starting the pump, the pump casing and suction pipe must be filled with water, and then the motor can be started to drive the pump shaft to drive the impeller and make the water perform high-speed rotation. The pressurized water line into the pump.
1. Check whether the pump vibrates abnormally. If vibration occurs, stop the pump immediately for inspection.
2. Check whether the bearing temperature is normal. Too high temperature will accelerate bearing damage and shorten the service life of the pump.
3. Check whether the lubricating oil level is normal. If the lubricating oil expires, it needs to be replaced frequently.
4. Check whether the lubricating oil temperature is normal
5. Check whether the lubricating oil is qualified
6. Check whether the leakage meets the requirements. For serious leakage, please check whether the mechanical seal is damaged.
7. Check whether the sealing fluid operates normally
8. Check whether the sealing cooling medium is normal
9. Check whether the cooling water system is normal
10. Check whether the grounding of the motor is intact. Please pay attention to whether the grounding bolt is loose and tighten it in time.
11. Check whether the motor vibration is normal
12. Check whether the motor bearing temperature is normal
13. Check whether the motor current is normal. If the current is too high, the centrifugal pump will not work properly.
14. Check whether the pump inlet pressure is normal and stable
15. Check whether the pump outlet pressure and flow are normal and stable

Vacuum Pumps for Food Packaging Machines

How to reduce the energy consumption of centrifugal pump?

The efficiency of centrifugal pump is the product of mechanical efficiency, volumetric efficiency and hydraulic efficiency. The efficiency of single-stage centrifugal pump unit is the product of pump efficiency and motor efficiency. How to reduce energy consumption and improve efficiency of centrifugal pump?
1. Application of frequency conversion energy-saving technology. For centrifugal pumps whose design parameters are greater than the actual working conditions, the centrifugal pump will always operate in the high efficiency zone after installing the variable frequency speed control device.
2. Promote the application of high-efficiency energy-saving permanent magnet motor, dual-power motor and other energy-saving new products on the main centrifugal pump.
3. Selection of centrifugal pump. When selecting a new pump, the pump produced by a large manufacturer should be selected to ensure the high efficiency of the centrifugal pump.
4. Maintenance of centrifugal pump.
(1) Frequently check and adjust the shaft end seal of the centrifugal pump to reduce the volume loss;
(2) After 10000 hours of operation, the centrifugal pump should be overhauled to restore the efficiency of the pump;
(3) Applying bellows sealing technology to centrifugal pump can completely eliminate the leakage of centrifugal pump and improve the volumetric efficiency.
5. Clean the filter cartridge regularly, check the pipe connection, and ensure that the inlet pipe of the centrifugal pump is smooth.
6. In strict accordance with the operating regulations of centrifugal pump, before starting the pump, the disc pump must be started, the inlet valve must be opened, the outlet valve must be closed, the exhaust and exhaust must be conducted, and the inlet pressure of the pump must be checked to see if it meets the requirements. Prevent pump cavitation caused by low supply pressure and insufficient flow.
7. Regularly check the pump efficiency of the centrifugal pump, find out the cause of low pump efficiency in time, and take corresponding measures to solve it.

dry screw vacuum pump of reasons for lack of air volume

Non clogging submerged pump

YW series non clogging submerged pump, GW tubular non clogging sewage pump and LW (WL) vertical sewage pump are all designed based on QW submersible sewage pump according to user requirements and different operating conditions. Their hydraulic models and QW pumps are welcomed and praised by users for their unique design and reliable quality after they are put on the market.
2、 Scope of application:
YW series non clogging submerged pump is applicable to the discharge of industrial, sewage and conveyor belt granular sewage such as factory sewage, sewage discharge stations in main residential areas, urban sewage treatment plant water distribution system, civil air defense drainage station, water supply equipment of water plants, hospitals, hotels, municipal engineering construction sites, mine auxiliary machinery, rural biogas digesters, farmland irrigation, etc. It can also be used in clean water and weak corrosive media.
3、 Service conditions:
1. When the rated voltage is 380 V and the power frequency is 50 Hz, this series of sewage pump products are applicable.
2. The medium temperature shall not exceed 120 ℃, the density shall be less than 1150 kg/m3, and the PH value shall be within the range of 5:9;
3. The height shall not exceed 1000m;
4. The annual viscosity of the conveying medium shall not exceed 1000 CP. The annual viscosity of the conveying medium shall not exceed 1000 CP.
5. When the product is working, it must be completely submerged, but the diving depth shall not exceed 10m;
6. The material of the product is mainly cast iron, which cannot be used in the medium with strong corrosion or strong corrosion.

Roots vacuum unit for oil return of preventive measures

Differences of Self priming Centrifugal Pumps

In order to better discharge the gas in the moisture absorption pipe and generate a certain vacuum value during the operation of the general centrifugal pump, the exhaust pipe must be used. For small pumps, the pump casing and water inlet must be filled with water before starting. In order to better avoid the jump of water injection, the bottom end of the water inlet is equipped with a unilateral pump bottom valve that opens when the water flows upward and closes when it flows downward; Generally, large centrifugal pumps with water seepage specifications above 300 mm are not equipped with bottom valve of water pump, but only use professional vacuum equipment to vacuum drinking water. There is no doubt that the startup of the feed pump will cause inconvenience, resulting in waste.
Principle: The centrifugal pump is operated by the centrifugal movement of water generated by the rotation of the impeller. Before starting the water pump, be sure to fill the pump housing and the moisture absorption pipe with water, and then start the motor to make the pump shaft push the impeller and water for high-speed running fitness exercise. The water produces centrifugal movement and is thrown to the edge of the impeller. The water is injected into the pressurized tap water pipeline of the pump through the gate of the volute pump housing.
Structure: The centrifugal pump operates by the centrifugal movement of water generated by the rotation of the impeller. The main structure of centrifugal pump is composed of 61 parts, namely impeller, pump housing, pump shaft, rolling bearing, sealing ring and ferrule joint.
The structural type of self-priming centrifugal pump has been improved to get rid of the shortcomings of general pipeline centrifugal pump. Self priming centrifugal pump has the advantage that the pump casing is of double volute structure. The detergent port is located on the edge of the pump impeller, and there is a large capacity vapor liquid separation chamber on the liquid outlet. Other structures are similar to single pole single suction centrifugal pumps, including sealing rings, mechanical seals, shafts and rolling bearings. When the self-priming pump is started for the first time during operation, the water diversion channel must be introduced into the pump casing, and the introduction amount can exceed the pump centerline in the pump casing. After that, the fully automatic suction pipe can be started at any time and anywhere, without introducing the diversion canal, so the application is more convenient than the pipeline centrifugal pump.
Principle: The design principle of self-priming pump is to fill the pump casing with water (or the pump casing itself has water) before starting the pump. After startup, the  impeller runs at a high speed to make the water in the impeller channel flow to the volute. At this time, the channel generates a vacuum pump to open the seepage check valve. The gas in the suction pipe enters the pump and reaches the edge through the impeller channel.
Structure: Self priming centrifugal pump is a kind of centrifugal pump, but compared with centrifugal pump, its big difference is that it has “self priming” characteristics. The main structure of self-priming pump is composed of suction chamber, liquid storage chamber, scroll chamber, liquid collection hole, vapor liquid separation chamber, etc.

What are the general mechanical installation rules for vacuum pumps?

Daily maintenance method of acid and alkali resistant centrifugal pump

1. The inlet and outlet pressure, flow and motor current of the centrifugal pump shall be kept in the normal use standard, and it is prohibited to pump for a long time. The flow and head of the acid and alkali resistant centrifugal pump shall be controlled within the range indicated on the signboard as far as possible to ensure that the acid and alkali resistant centrifugal pump operates at the design point, so as to achieve the effect of energy saving and consumption reduction.
2. During the operation of acid and alkali resistant centrifugal pump, the bearing temperature shall not exceed the working temperature by 50 ℃, and the upper limit shall not exceed 90 ℃.
3. Check the sealing condition of centrifugal pump frequently, and report to the workshop for maintenance in case of leakage.
4. Always check the quality of lubricating oil and oil level indicator in the oil tank, and replace them immediately if they are found to be deteriorated to avoid false liquid level.
5. The filter press pump shall be sealed with cooling circulating water. The cooling circulating water shall be kept smooth. The cooling circulating water shall not be interrupted within one week after the new seal ring is replaced.
6. Check whether the pump base and motor are firm. If they are loose, the centrifugal pump will vibrate. Stop the pump immediately to check the root cause when the pump makes an abnormal noise.

7. The centrifugal pump shall be operated for 300 hours within 3 months to replace the lubricating oil, and the lubricating oil shall be replaced within 3-6 months for the second time. After 6~12 months, it shall be lubricated and replaced.
8. Check the condition of instruments and leads to see if the pipes are leaking or loose, or damaged in other forms. If maintenance is needed, it should be carried out immediately.
9. Whether the mechanical seal is always leaking. If there is a leak, the compression degree of the moving ring should be adjusted in time to ensure that the sealing surface does not leak. Do not press too tightly to reduce the service life of the sealing property. Note: The filter press pump is the most demanding working condition in the process flow, and also the position with the largest consumption of spare parts. When the sealing leakage is not serious, the seal will not be replaced. Generally, the closed circulation reuse system of the leaking liquid should be considered in the design, but it is subject to the scarcity of materials.
10. When the acid and alkali resistant centrifugal pump is used in cold winter, the liquid in the pump body and pipeline shall be completely discharged when it is stopped. Avoid freezing.
11. If the acid and alkali resistant centrifugal pump is not used for a long time, it is necessary to disassemble all the pumps, wipe off the water, coat the rotating parts and joints with grease, and install them properly for maintenance.
12. For pumps that are not used, turn the gear once before each shift to ensure that the pumps are in good use.
13. When the acid and alkali resistant centrifugal pump is to be stopped, first turn off the valve and pressure gauge, and then disconnect the motor power supply.

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Components of centrifugal pump

Centrifugal pumps are composed of many parts. They can be roughly divided into three categories according to the working state of each part during operation
Type: rotating part, fixed part J4: and connecting part. Take the single-stage single suction horizontal diaphragm pump as an example, as shown in Figure 2.4
The function, composition, structure and material of each part under.
2.2.1 Rotating parts
1 Impeller (also called working wheel)
The barking wheel is the main part of the water pump, or even the core part of the water pump. The centrifugal system depends on the high-speed rotation of the impeller
Transferring water for energy calibration.
The wheel rubber of the gear pump is composed of two circular covers. If there is a curved blade between the covers
The two cover plates are connected together, and the space groove enclosed by the two adjacent blades and the front and rear cover plates is generally referred to as the flow of water.

The shape and size of the impeller are determined by test and calculation, which can be generally divided into leather suction impeller and double suction impeller.
The front cover plate of the impeller with a round hole for water inlet is called a single suction impeller, and the front and rear cover plates of the impeller with a round 7L water inlet are called double suction impeller
Suction impeller.
It is a teaching suction impeller. It is equipped with a single-sided chock wheel cover plate for water intake, while the rear cover plate is H without the cover plate of the wheel intake; Symmetrical shape. It is a double suction impeller. The front and rear cover plates of the impeller are equipped with round water inlets
The cover plate is symmetrical and generally used for large flow centrifugal pumps.
In addition to sufficient mechanical strength, wear resistance and corrosion resistance of materials shall also be considered
Performance. Recently, most impellers of screw pumps are made of cast iron, cast steel and bronze, and hard plastic and alloy steel are also used.

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How to prevent the motor of centrifugal pump from being burnt?

Dadonghai Pump Wuxi Co., Ltd. is a professional centrifugal pump manufacturer. When selecting centrifugal pumps for customers, our pump manufacturers will provide perfect pre-sales services such as centrifugal pump models, centrifugal pump prices, etc. for customers’ reference, and our pump manufacturers can provide customers with customized pump products. This information is about how to prevent the motor of centrifugal pump from being burnt:
The motor may fail during operation, and burning is one of them, which not only affects the normal work, but also increases the cost, causing us a lot of trouble. There are many reasons why the motor is burnt out, which is related to the quality of the machine itself and whether the centrifugal pump is used correctly.
After the power is turned on, carefully observe the working condition of the centrifugal pump. The outlet water should be connected evenly and the centrifugal pump can be used without vibration and noise. In case of sudden shutdown during operation, disconnect the power supply immediately and check the cause. The interval between two starts of the centrifugal pump shall be limited to the return of all water in the centrifugal pump. If it starts too early, the motor will be burnt due to excessive resistance and water hammer in the water pipe. In addition, if the centrifugal pump is installed in the well, it should be noted that the flow of the centrifugal pump should be consistent with the normal water yield of the well, otherwise it will form an empty machine and burn the motor.
In order to ensure the normal operation of centrifugal pumps, Dadonghai Pump Industry reminds everyone to pay attention to the following points before using centrifugal pumps:
1. Check whether the centrifugal pump motor winding is open circuit. The insulation condition can be measured with a 500V megohmmeter. When the insulation resistance is lower than 0.5 megohm, the centrifugal pump cannot be used.
2. Remove the filter screen and check whether the rolling pump shaft is sensitive. If not, adjust it before use.
3. Whether the selection of gate fuse capacity is appropriate, and other wires cannot be used to replace the fuse.
4. Turn on the power and check whether the impeller works normally (the power on time shall not exceed 3–5 seconds, otherwise the motor may be burnt out.

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In depth analysis, can the magnetic pump run idle?

With the aggravation of the environmental protection situation, more and more chemical enterprises are required to use magnetic pumps to transport various corrosive materials. As we all know, magnetic pumps cannot idle. As long as they idle for a few minutes, the friction between the shaft and the shaft sleeve inside them will produce extremely high temperature, quickly wear the graphite bearings and shafts, and even burn the inner rotor.
In recent years, domestic magnetic pump manufacturers claim to be able to do anti idling magnetic pumps. Is it true? Does idling magnetic pump really work? Can it really idle for a long time?
Today, I would like to introduce some details to you. I hope it will be helpful to users.
At present, there are two kinds of idling magnetic pumps produced by some domestic manufacturers. One is that ceramic rolling bearings are used to replace the original sliding bearings. When the magnetic pump is short of liquid, the friction coefficient of the rolling bearings is low and the heat generated is relatively small. Therefore, the magnetic pump can be idling without burning the bearings and rotors. The disadvantages of this structure are: it cannot carry high torque, materials with higher density cannot be transported normally, and ceramic bearing balls are fragile.
The other is the LHC idling fluorine lined magnetic pump developed by Green Ring. This magnetic pump is a complete upgrade of the main shaft and shaft sleeve on the original traditional basis. It is filled with nano carbon powder technology to achieve the function of idling and self-lubricating. Relatively speaking, the latter is more in line with idling requirements in terms of technology and practical theory.

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The Harm of Centrifugal Pump Cavitation


The cavitation phenomenon of centrifugal pump is one of the common faults of centrifugal pump. Once cavitation occurs in the pump, its flow and head performance will not only decline, but also show obvious high noise and vibration. In serious cases, it will even interrupt the liquid flow in the pump and cannot work normally. Cavitation will also damage the flow passage components of the pump, and even affect the pipeline system. There are many reasons for cavitation, such as quality problems of centrifugal pump products, improper use of operators, etc. Before leaving the factory, the products will pass the quality inspection of multiple procedures, so the influence of human factors is greater. In the working state, the working environment and operating factors of centrifugal pumps account for the vast majority of the cavitation phenomenon of centrifugal pumps.
Cavitation will affect the normal operation of centrifugal pumps, causing many serious consequences.
The performance of centrifugal pump is reduced due to cavitation
Centrifugal pump transfers energy to the medium through the rotation of the impeller and converts it into the pressure energy of the medium. However, cavitation will seriously interfere with the energy transfer between the impeller and the liquid. When cavitation occurs, a large number of bubbles will be generated in the medium, which will block the impeller flow passage, and vortex will be generated locally, increasing the flow loss, reducing the pump flow, head and efficiency. In serious cases, it will also lead to flow interruption, making the centrifugal pump unable to work normally.
Cavitation will damage the overcurrent components
Among the flow passage components of centrifugal pump, the impeller is the part most affected by cavitation. When cavitation occurs, many small pits will gradually appear on the surface of metal materials, and then the pits will continue to develop and expand into honeycomb and groove shapes. In serious cases, perforation will occur, and even the impeller will break, seriously affecting the service life of the pump.
Noise and vibration of pump caused by cavitation
When cavitation occurs, high-frequency liquid collisions will produce various noises. In serious cases, the pump will emit crackling explosions, and at the same time, it will induce the vibration of the pump unit, which in turn will accelerate the generation and rupture of bubbles. When the frequency of liquid hammer is the same as the natural frequency of the pump unit, strong cavitation resonance will occur, which will rapidly increase the amplitude. At this time, if you want to protect the centrifugal pump from greater damage, you must immediately stop for inspection.

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