What are the benefits of centrifugal water pump packing seals? What s the downside?

Advantages of packing seals.

1) There is a certain elastoplasticity. When the packing of the water pump is axially compressed, a large radial compression force can be generated to obtain a seal; When there is vibration or eccentricity of the machine and shaft and there is wear of the packing, it can have a certain ability to compensate (follow-up).

2) There is a certain strength. So that the pump packing will not be damaged before it is worn out.

3) High chemical stability. That is, it has good adaptability to sealing fluids and lubricants, and is not corroded and swollen by the fluid medium, and does not pollute the medium.

4) Good impermeability. Because the fluid medium has a certain permeability effect on many fibers, it has high requirements for the compactness of the microstructure of the filler, so it is often necessary to impregnate and fill the corresponding filler and lubricant when making the filler of Sanchang Pump Industry.

5) Good thermal conductivity. It is easy to dissipate heat quickly, and can withstand a certain high temperature when the friction heats up.

6) Good self-lubrication. That is, the coefficient of friction is low and wear-resistant.

7) The packing manufacturing process is simple, easy to assemble and disassemble, and the best is low.

At the same time, there are fewer materials that can meet the above requirements, such as some metal soft fillers, carbon fiber fillers, flexible graphite fillers, etc., which have good performance and a wide range of adaptation, but they are more expensive. Some natural fiber fillers, such as hemp, cotton, wool, etc., are not high, but their performance is slightly poor, and the scope of adaptation is relatively narrow. Therefore, various requirements should be considered comprehensively and comprehensively in the selection of pump packing materials.

Disadvantages of packing seals.

1) The adhesive contact force of the packing seal** is the axial pressure of the gland on the packing and the packing produces radial expansion force of the packing, resulting in the formation of large friction between the packing and the bushing, so it is necessary to replace the worn bushing frequently.

2) It is necessary to lose 10 15 shaft power to overcome the friction between the bushing and the packing material to achieve sealing.

3) The leakage of the packing seal is very easy to cause leakage into the bearing box, resulting in damage to the bearing.

4) In the process of using the packing seal, because the packing is often in an abnormal use state, the wear of the packing and the damage of the shaft sleeve are aggravated, so that the use of the packing seal is in a vicious circle.

5) In order to keep the friction between the packing and the shaft or bushing, there must be a quantitative leakage, resulting in the loss of cooling water. In short, the advantage of packing seal is that it is simple and easy, but the disadvantage is that the maintenance workload is large, the loss of power is also large, and because it always has a certain leakage, it is not suitable for transporting flammable, explosive, toxic and valuable liquids.

The packing is easy to replace without dismantling, and the pressure can be adjusted. The disadvantage is that it is not the pair seal that will drip water, and the water seal will not drip water, but it is not as durable as the packing.

I don't know the pros, I don't know the disadvantages.

Hello dear<>

Thank you for your patience, the higher the suction lift of the centrifugal pump, the sealing of the packing is indeed realized, and the packing is subject to the pressure of the liquid in the pump, so as to achieve the purpose of sealing. However, when the suction lift of the centrifugal pump increases, the pressure of the liquid decreases and the sealing effect of the packing decreases. Therefore, in order to ensure the effect of packing sealing, the following measures should be taken when the suction stroke of the centrifugal pump is high:

1.Choose the right filler: The appropriate packing material and shape should be selected to improve the sealing of the packing.

2.Multistage pump: Multistage pump can be used to increase the head of the pump, so as to reduce the suction lift, increase the pressure of the liquid, and enhance the sealing effect of the packing.

3.Use of vacuum pump: A vacuum pump can be installed at the suction inlet of the centrifugal pump to reduce the suction stroke of the pump, increase the pressure of the liquid, and improve the sealing effect of the packing.

In short, in order to ensure the effect of packing branch sealing, it is necessary to make reasonable selection and design according to the actual working conditions of the centrifugal pump. Thank you for your consultation, I hope the information checked by the teacher can help you <>

Summary. Dear , hello, thank you for your consultation, about your questions, for you to answer the following: the suction lift of the centrifugal pump refers to the height of the pump to pump the liquid in the vertical direction, which has a certain relationship with the performance of the packing seal.

In general, the higher the suction lift of a centrifugal pump, the more susceptible the performance of the packing seal will be. Because the inlet pressure of the pump is low at high lift conditions, the liquid is prone to vaporization, which makes packing seals more challenging. At this point, the leakage of the packing seal may increase and the seal life will be shortened.

To solve this problem, the following measures can be taken:1Select the appropriate packing sealing material, such as high-temperature corrosion-resistant packing sealing material, to improve the resistance of the packing seal.

2.Multistage pumps or increased pump diameters are used to reduce the suction lift of the pump and reduce the burden on the packing seal. 3.

A vacuum valve or gas** device is installed at the inlet of the pump to reduce the possibility of vaporization of the liquid and reduce the burden on the packing seal. In short, the higher the suction lift of the centrifugal pump, the more susceptible the performance of the packing seal will be, and corresponding measures need to be taken to ensure the reliability of the packing seal. 

Dear , hello, thank you for your consultation, about your questions, for you to answer the following: the suction lift of the centrifugal pump refers to the height of the pump to pump the liquid in the vertical direction, which has a certain relationship with the performance of the packing seal. In general, the higher the suction lift of a centrifugal pump, the more susceptible the performance of the packing seal will be.

Because the inlet pressure of the pump is low at high suction lift conditions, the liquid is prone to vaporization, which makes the packing seal more challenging. At this point, the leakage of the packing seal may increase and the seal life will be shortened. To solve this problem, the following measures can be taken:

1.Select the appropriate packing sealing material, such as high-temperature corrosion-resistant packing sealing material, to improve the resistance of the packing seal. 殺2.

Use a multistage pump or increase the diameter of the pump to reduce the suction lift of the pump bank and reduce the burden on the packing seal. 3.A vacuum valve or gas ** device is installed at the inlet of the pump to reduce the possibility of vaporization of the liquid and reduce the burden of packing seals.

In short, the higher the suction lift of the centrifugal pump, the more susceptible the performance of the packing seal will be, and corresponding measures need to be taken to ensure the reliability of the packing seal. 

Dear, thank you for your consultation, may you be warm in winter, may you not be cold in spring, may you have lights in the dark, umbrellas in the rain, may you be accompanied by a lover on the road, and what you want can be realized. Talk

There are two commonly used shaft sealing devices for centrifugal pumps: packing seal and mechanical seal.

Function: The shaft sealing device ensures the normal and efficient operation of the centrifugal pump. If the annular gap between the centrifugal pump is not sealed or not well sealed, the outside air will penetrate into the low-pressure area of the center of the impeller, so that the flow rate and efficiency of the pump will decrease.

In severe cases, the flow rate is zero air binding, and in general, mechanical or packing seals can be used to achieve a shaft-to-shell seal.

A: Q1 mechanical seal and packing seal.

Answer: Q2 Before disassembling the bearing, remove the nut on the packing gland and exit the packing gland. Then disassemble the bearing parts, disassemble the packing gland, take out the outer packing with a pointed object (generally 3 turns of the outer packing), then take out the water seal ring, and take out the inner packing with a pointed object (generally 2 turns of the inner packing).

Cut the new packing with the length of the removed old packing, wrap the straight packing on the bare shaft and rub it repeatedly to make the straight packing bend, and then lower the new packing into the sealing cavity, install it according to the number of turns before disassembly, load the water seal ring and the outer packing, and cover the packing gland, with a slight strength nut. After installing the bearing box, lock the nut on the packing gland, and the locking method will first put the nut back to death and then return a circle, and then the turning can be smooth.

Ask the landlord to give points, thank you.

The sealing devices of centrifugal pumps mainly include: mechanical seals, packing seals, and a kind of power seal that is not commonly used.

Packing replacement requires the length of the cut packing to be appropriate, the incision is at a 45-degree angle, the incision lap is seamless, and each lap is staggered by 120 degrees. In addition, the gland should be pressed moderately, not too tightly. You can wait for the centrifugal pump to be turned on before tightening.

Centrifugal pump selection of mechanical seal - mainly because of more sealing performance requirements, rotating equipment in operation, if there is no sealing equipment between the pump casing and the shaft, the medium will flow out directly, if it is a toxic and harmful medium, there is a safety problem, when there are no special requirements, the use of packing seal, mainly low cost; If the working conditions are high, it is necessary to choose a mechanical seal, and the matching flushing scheme can achieve good sealing performance, and at the same time, the good service life of the mechanical seal is also unachievable by packing. Chongqing Water Pump Factory produces large-scale multi-stage self-balancing centrifugal pumps and various types of single-stage centrifugal pumps, metering pumps, reciprocating pumps, hydraulic diaphragm pumps, complete sets of dosing assembly, descaling systems, and first, second and third types of pressure vessels.

Why do centrifugal pumps need mechanical seals – the main reason is the long service life of mechanical seals.

The mechanical seal has a moving ring, also known as a compensation ring, which can compensate for the wear at the sealing surface in time (axial seal, also called end seal). Packing seals (radial seals) do not compensate for radial wear.

The sealing oil has the function of lubrication and cooling, and also has the function of preventing the leakage of the conveying medium and the entry of air or flushing water into the stuffing box under negative pressure.

The sealing pressure should be 0 05 0 2MPa higher than the pressure of the medium to be sealed, and the sealing oil should be a clean, particle-free, non-evaporative vaporization and non-corrosive liquid that does not affect product quality. The oil sealing system usually includes pumps, tanks, and auxiliary equipment that plays the role of pressure balancing, filtration, cooling, etc.

Application features: There are two types of sealing of vacuum devices, one is that the seal separates a container filled with liquid medium from the external vacuum space. In this case, the main function of the seal is to prevent the liquid medium from leaking into the vacuum space.

On the other hand, the seal separates the inner and outer chambers of the vacuum, and its function is to maintain the required vacuum level.

This situation is complicated by the fact that even a slight leakage of the surrounding gaseous medium into the vacuum chamber will reduce the vacuum level. If corrosive gases leak in, the vacuum equipment can be damaged. In many cases, the degree of vacuum and the cleanliness of the vacuum space have a decisive influence on the quality of the various processes carried out under vacuum conditions.

The function of the mechanical seal of the centrifugal pump is to prevent the leakage of the medium in the pump and ensure the normal operation of the pump. Mechanical seals are usually composed of sealing rings, packing, springs, etc., and prevent media leakage through the friction between the sealing ring and the pump shaft or pump casing and the filling effect of the packing. At the same time, the mechanical seal can also withstand the pressure and temperature of the pump to ensure the safe operation of the pump.