What certifications should I require for scraper seals?

Scraper seals play a crucial role in protecting hydraulic and pneumatic systems by preventing contaminants from entering cylinders, thereby extending the lifespan of seals and other components. For professionals in the seal manufacturing industry, understanding the intricacies of scraper seals is essential when making procurement decisions.

1. What are scraper seals, and why are they important?

Scraper seals are sealing elements installed in hydraulic and pneumatic cylinders to remove dirt, moisture, and foreign particles from the piston or rod surface before they enter the cylinder system. This function protects the medium and subsequent seals from contamination, ensuring the operational reliability of the system.

2. What materials are commonly used for scraper seals?

Scraper seals are typically made from materials such as Nitrile (NBR), Fluorocarbon (FKM), Polyurethane (PU), and PTFE. The choice of material depends on factors like temperature range, chemical compatibility, and wear resistance. For instance, NBR is suitable for general applications, FKM for higher temperatures and chemical resistance, PU for high abrasion resistance, and PTFE or filled PTFE for low friction and extreme conditions. ((https://www.polypacseals.com/top-scraper-seals-manufacturers/))

3. What certifications should I require for scraper seals?

Certifications ensure that scraper seals meet industry standards and specifications. For example, the Hydrowype A-Series scrapers conform to the MS28776 standard, which governs aspects like materials, plating, and geometry. Additionally, the SAE Aerospace Standard AS4052C provides guidelines for gland design and installation of scraper/wiper rings in landing gear shock struts.

4. How do I specify a scraper seal in a drawing or Bill of Materials (BOM)?

When specifying a scraper seal, include the following details:

• Seal type (scraper/wiper/dust ring)

• Cross-section drawing

• Material compound (including hardness)

• Rod diameter and tolerance

• Gland dimensions

• Surface finish and plating of the rod

• Expected operating temperature range

• Media exposure

• Motion profile (stroke speed, frequency)

• Required life cycles

Indicate any relevant standards or drawings, such as ISO grooves for O-rings. ((https://www.polypacseals.com/article/scraper-seals-buying-guide-material/))

5. What tests should be performed before purchasing scraper seals?

Before procurement, request material certificates and perform or require tests such as:

• Abrasion loss (Taber or custom)

• Compression set

• Tensile strength

• Low/high-temperature flexibility

• Immersion/swelling in the actual hydraulic fluid

For critical applications, conduct a bench test of the entire cylinder assembly with environmental contamination (dust/water) to validate performance under realistic duty cycles. ((https://www.polypacseals.com/article/scraper-seals-buying-guide-material/))

6. What are the key industry standards for scraper seals?

Industry standards provide guidelines for the design, material selection, and testing of scraper seals. For example, the API Standard 682 outlines requirements for end-face mechanical seals in centrifugal and rotary pumps, while the SAE Aerospace Standard AS4052C specifies gland design for scraper/wiper rings in landing gear shock struts.

7. How do I choose the right scraper seal for my application?

Selecting the appropriate scraper seal involves considering factors such as installation space, temperature range, medium compatibility, lifting speed, counter surface, installation option, friction behavior, service life expectancy, and cost. Understanding these criteria helps in choosing a scraper that aligns with specific application requirements.

8. What are the advantages of choosing Polypac for scraper seals?

Polypac offers advanced materials and custom PTFE-filled scraper seals, providing deep materials expertise and custom manufacturing advantages. This is especially valuable for special working conditions or when a custom compound/profile is required. Polypac's commitment to quality and innovation ensures that their scraper seals meet the highest industry standards, offering reliability and performance. ((https://www.polypacseals.com/top-scraper-seals-manufacturers/))

In conclusion, understanding the specifications, certifications, and standards associated with scraper seals is vital for professionals in the seal manufacturing industry. By carefully considering these factors, you can ensure the selection of scraper seals that enhance the performance and longevity of your hydraulic and pneumatic systems.