How to solve the shaft seal leakage problem of Dalian Chemical Pump

1、 The seriousness and impact of shaft seal leakage problem

As a core equipment in the chemical production process, the operational stability of Dalian chemical pumps directly affects the safety and efficiency of the entire production system. Shaft seal leakage is one of the common faults in chemical pumps, which not only causes material loss and environmental pollution, but also may lead to serious safety accidents. According to statistics, shaft seal leakage accounts for more than 30% of equipment failures in the chemical industry, especially in the transportation of corrosive, flammable, explosive or toxic media, where the risk of leakage is more prominent.

Leakage of shaft seals can cause various problems: the leaked chemical medium may corrode the pump body and surrounding equipment; Secondly, the leakage of volatile media may form explosive mixtures of gases; Furthermore, the leakage of toxic media can endanger the health of operators; Leakage can also lead to a decrease in pump efficiency, increased energy consumption, and maintenance costs. Therefore, solving the problem of shaft seal leakage is of great significance for the safety production and economic benefits of chemical enterprises.

2、 Analysis of Common Causes of Shaft Seal Leakage

1. Mechanical seal failure

Mechanical seal is a commonly used form of shaft seal in chemical pumps, and its failure reasons are complex and diverse:

Sealing surface wear: The medium contains solid particles or crystals that cause sealing surface wear

Sealing ring deformation: The material undergoes thermal deformation or installation stress under high temperature conditions, resulting in uneven sealing surfaces

Spring failure: Insufficient spring force or jamming causes the sealing surface to not fit tightly

Auxiliary system malfunction: Failure of flushing and cooling systems resulting in high sealing surface temperature

2. Packing sealing issue

Some chemical pumps still use packing seals, and common problems include:

Packing wear: Leakage caused by packing wear after long-term operation

Improper clamping force: too tight leads to wear of the shaft sleeve, while too loose results in insufficient sealing

Corrosion of the medium: The packing loses its elasticity due to the corrosion of the medium

Poor lubrication: Lack of lubrication leads to dry friction between the packing and the shaft sleeve

3. Improper design and selection

Mismatched sealing type: The appropriate sealing form was not selected based on the characteristics of the medium

Material selection error: The sealing material is not resistant to medium corrosion or high temperature

Parameter design deviation: Parameters such as pressure and speed exceed the sealing tolerance range

4. Installation and maintenance issues

Insufficient installation accuracy: coaxiality and perpendicularity deviation lead to seal wear deviation

Delayed maintenance: Failure to regularly inspect and replace worn parts

Improper operation: Improper start stop pump program causing seal impact

3、 System solution for shaft seal leakage

1. Reasonably choose the sealing type

Scientifically select the sealing form based on the characteristics of the medium and working conditions:

Mechanical seal: suitable for most chemical media, especially high-pressure, high-speed, and corrosive working conditions

Double end mechanical seal: provides dual protection for toxic, flammable, and expensive media

Bellows sealing: solving the sealing problem of easily crystallized and high viscosity media

Magnetic driven unsealed pump: completely eliminates the risk of leakage, suitable for special hazardous media

2. Optimize the design of the sealing system

Material selection: Choose a combination of corrosion-resistant and high-temperature resistant sealing materials based on the characteristics of the medium

Flushing plan: Design a reasonable flushing system to maintain the cleanliness and cooling of the sealing surface

Buffer system: Set up a buffer system to isolate hazardous media

Monitoring device: Install leak detection and alarm system

3. Improve installation and maintenance quality

Installation points:

Ensure that the radial runout of the shaft is ≤ 0.05mm

Parallel deviation of sealing surface ≤ 0.0005mm

Adjust the compression amount of the spring according to the technical specifications

Use specialized tools to avoid damage to seals

Maintenance strategy:

Establish a regular inspection system and record the sealing status

Develop a preventive maintenance plan and promptly replace worn parts

Maintain the normal operation of auxiliary systems (flushing, cooling)

Train professional maintenance personnel and standardize operating procedures

4. Adopting advanced sealing technology

Upstream pumping seal: utilizing the principle of fluid dynamic pressure to achieve zero leakage

Dry gas seal: non-contact seal, suitable for high-speed working conditions

Intelligent sealing system: Integrated sensors for real-time monitoring of sealing status

Special coating technology: enhancing the wear and corrosion resistance of the sealing surface

4、 Targeted solutions for typical leakage problems

1. Leakage of corrosive media

Choose corrosion-resistant alloy or ceramic sealing rings

Increase external flushing to dilute corrosive media

Sealed with PTFE corrugated tube

Regularly check the corrosion condition of the sealing surface

2. Leakage of easily crystallized media

Design heating jacket to prevent medium crystallization

Using a large spring structure for sealing to prevent jamming

Increase flushing flow to keep the sealing surface clean

Consider using non-contact sealing

3. Leakage of high-temperature medium

Choose high-temperature resistant materials such as silicon carbide and hard alloys

Strengthen the design of the cooling system

Sealed with metal bellows

Consider thermal compensation structure to prevent thermal deformation

4. Leakage of media containing particles

Set up a filtering device to remove large particles

Choose a combination of hard to hard sealing materials

Design a self flushing structure to prevent particle accumulation

Consider adopting wear-resistant coating technology

5、 Management measures to prevent shaft seal leakage

Establish a sealed file: record the sealing type, parameters, and replacement history of each pump

Improve operating procedures: standardize start stop procedures to avoid water hammer and dry operation

Strengthen personnel training: Improve the professional skills of operation and maintenance personnel

Implementation status monitoring: using vibration analysis, temperature monitoring and other methods to predict the sealing status

Establish an emergency plan: Develop a leak emergency response process and equip necessary protective equipment

The problem of shaft seal leakage in chemical pumps needs to be systematically solved from both technical and management perspectives. Through scientific selection, optimized design, standardized installation and maintenance, combined with the application of advanced sealing technology, the risk of leakage can be significantly reduced. At the same time, establishing a comprehensive preventive maintenance system and emergency plan can minimize the losses caused by leaks to the greatest extent possible. With the continuous development of sealing technology, the reliability of shaft seals in chemical pumps will be further improved, providing strong guarantees for the safe, environmentally friendly, and efficient operation of chemical production.