Key Questions to Ask When Ordering double lip oil seal

Oil seals are an important part of the MRO inventory in many industries. Oil seals are used for retaining lubricants in machinery with rotating parts. Oil seals prevent the fluid from leaking between the shaft and housing. If you are an MRO buyer looking for information on oil seals, here are some frequently asked questions on oil seal online purchase and their answers:  

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Question 1: What are oil seals used for?

The main purpose of using oil seals is to retain the lubricants. It prevents lubricants from leaking and also it prevents foreign particles from contaminating lubricants. They also help in preventing the mixing of lubricants such as oil and grease. 

Question 2: How many oil seal types are there?

Oil seals can be broadly categorised into two types: 

• Metal cased oil seals: These are used in metal housing bore. The choice of the same material (metal) allows for equal contraction and expansion of the materials during operation, preventing leakage. 
• Rubber cased oil seals: They are used in applications where metal-cased seals may fail. For instance, thermal expansion can cause premature failure of metal-cased oil seals. Oil seals with a rubber case do not rust easily in comparison to oil seals with metal cases. In high temperatures and high pressures, rubber seals can expand and contract, providing a better fit. 

These two oil seals can be further divided into the following types: 

1. Single lip oil seals: These oil seals do not have springs. They are not recommended for use in applications in which the environment contains dirt or contaminants.
2. Double lip oil seals: Double lip oil seals have two lips. They are better at separating fluid and preventing contamination. 

Question 3: What are the selection criteria for seals?

Selecting the right oil seal for your machine is important as they are crucial for the maintenance and integrity of a given application. There are a lot of factors that must be considered when selecting oil seals. Some of the factors are: 

• Shaft speed 
• Temperature
• Pressure
• Shaft hardness 
• Shaft surface finish
• Concentricity 
• Shaft and bore tolerances
• Runout
• Lubricant

In addition to mechanical applications, other factors to be considered include: 

• Ability to perform in extreme environments
• Long shelf life
• Easy assembly
• Low friction properties
• Increased strength properties to work in stressful environments

Question 4: Where are oil seals used? 

Contact us to discuss your requirements of gearbox oil seal factory. Our experienced sales team can help you identify the options that best suit your needs.

Oil seals are an integral part of any rotating and moving part assembly. Oil seals are used in gearboxes and hydraulic cylinders. 

Question 5: What is the most common cause of seal failure?

Improper installation is the most common cause of seal failure. Besides that, wear and tear, chemical incompatibility and irregular maintenance can lead to seal failure. 

Question 6: Where to buy unused and genuine oil seals? 

1. Design: Single-lip oil seals have a single sealing lip that contacts the shaft, while double-lip oil seals have two sealing lips, with the outer lip designed to prevent contaminants from entering the machinery and the inner lip to retain lubricants.

2. Sealing Capabilities: Single-lip oil seals may not be as effective as double-lip seals in preventing contamination, as they have only one sealing surface. Double-lip oil seals offer improved sealing capabilities due to the presence of two sealing lips. The outer lip protects the seal from dust, dirt, and other contaminants, while the inner lip retains the lubricant and prevents it from leaking out.

3. Friction: Single-lip oil seals have lower friction, which allows them to be used in high-speed applications. Double-lip seals may have higher friction, which can limit their use in high-speed applications.

4. Cost: Single-lip oil seals are typically less expensive than double lip seals.

Here is a table summarizing the differences between single-lip and double-lip oil seals:

Feature Single-Lip Oil Seals Double-Lip Oil Seals Sealing Lips Single Double Sealing Capabilities Less effective against contamination More effective against contamination Friction Lower Higher Cost Less expensive More expensive

The choice of single lip and double lip oil seal depends on the specific application requirements, such as operating speed, pressure, temperature and pollutant exposure. Consulting the seal manufacturer (NNK) or engineer can help to ensure that the appropriate seal design is selected for a specific machine and application.