O-ring 240x3 VMQ 70 ShA - Silicone O-ring

Product Description

O-ring 240x3 VMQ 70 ShA is a silicone rubber sealing ring with an inside diameter of 240 mm, a cross-sectional diameter of 3 mm and a nominal outside diameter of 246 mm. Manufactured from VMQ silicone rubber with a nominal hardness of 70 Shore A, it is primarily designed for static sealing applications in industrial machinery, equipment housings and large mechanical assemblies.

The O-ring features a large diameter and a relatively small cross-section, making it suitable for appropriately designed sealing grooves in covers, flanges and industrial equipment.

VMQ silicone rubber offers good resistance to high and low temperatures, ozone, ultraviolet radiation and atmospheric ageing. Its flexibility across a broad temperature range makes it suitable for sealing applications exposed to changing thermal conditions.

The material may also be identified as MVQ in commercial product descriptions. VMQ is the standard designation used in international technical documentation.

Dimensions of O-ring 240x3 VMQ 70 ShA

The nominal outside diameter is calculated as follows:

240 mm + 2 x 3 mm = 246 mm.

All dimensions are nominal. Actual dimensional tolerances depend on the manufacturing specification of the particular product.

VMQ Silicone Rubber - Material Properties

VMQ is the standard designation for methyl vinyl silicone rubber, an elastomer used in technical sealing applications requiring flexibility, temperature resistance and resistance to environmental ageing.

The alternative designation MVQ is also encountered in commercial descriptions of silicone rubber seals.

Silicone elastomers are particularly valued for their ability to maintain elastic properties under varying temperature conditions.

Key characteristics of VMQ silicone rubber include:

• Good resistance to elevated temperatures.

• Flexibility at low temperatures.

• Excellent resistance to ozone.

• Excellent resistance to UV radiation.

• Good resistance to atmospheric ageing.

• Good electrical insulation properties.

• Flexibility across a broad temperature range.

• Generally lower abrasion and tear resistance compared with many NBR rubber compounds.

Temperature Resistance

VMQ silicone rubber is commonly used in applications requiring good resistance to both elevated and low temperatures.

However, the exact permissible operating temperature range depends on the specific silicone compound, exposure duration and operating medium.

Without manufacturer-specific technical documentation, exact minimum and maximum operating temperatures should not be assigned to this O-ring.

Chemical Resistance

Silicone rubber provides good resistance to ozone and atmospheric conditions but is not universally compatible with all chemical substances.

Potential limitations may involve:

• Certain oils and fuels.

• Organic solvents.

• Chemicals that cause elastomer swelling.

• Media that may degrade specific silicone compounds.

Important: Material compatibility must be verified for the specific VMQ compound, operating medium, temperature and application conditions.

Construction and Sealing Principle

The O-ring 240x3 VMQ 70 ShA is a continuous elastomeric sealing ring with a circular cross-section.

When installed in a properly designed sealing groove and compressed between mating surfaces, the O-ring undergoes controlled deformation. The resulting contact pressure creates a sealing barrier that helps prevent the passage of liquids or gases through the joint.

For large-diameter O-rings, correct groove geometry, uniform positioning and controlled compression are particularly important.

Sealing performance depends on:

• Correct O-ring dimensions.

• Groove dimensions and geometry.

• Appropriate cross-sectional compression.

• Surface finish of mating components.

• Operating temperature and pressure.

• Chemical compatibility with the sealing medium.

• Deformation of the mating components.

• Installation and operating conditions.

Due to the mechanical properties of silicone rubber, VMQ O-rings are generally better suited to static sealing applications than to assemblies involving continuous friction or intensive dynamic movement.

Applications of Silicone O-ring 240x3

The O-ring 240x3 VMQ 70 ShA can be used in industrial equipment requiring large-diameter silicone sealing rings with a relatively small cross-section.

Typical applications may include:

• Static sealing of large equipment covers and housings.

• Flanged connections with appropriately designed sealing grooves.

• Heating systems and thermal equipment.

• Electrical and electronic equipment enclosures.

• Industrial machinery and production equipment.

• Technical assemblies exposed to ozone and UV radiation.

• Selected industrial installations requiring flexible silicone seals.

The 240 mm inside diameter makes this O-ring suitable for appropriately designed large mechanical connections.

However, its dimensions alone do not establish suitability for every flanged or pressurized connection. Correct selection requires consideration of groove geometry, pressure, temperature and sealing medium.

Applications involving food contact, drinking water or medical equipment require appropriate compliance documentation for the specific product. The VMQ material designation alone does not confirm such approvals.

Installation and Operating Recommendations

Before installing the O-ring 240x3 VMQ 70 ShA, inspect the sealing groove and mating surfaces to ensure they are clean and free from mechanical damage.

Due to the large diameter of the ring, particular attention should be paid to uniform positioning around the entire circumference.

Recommended installation procedures:

• Thoroughly clean the sealing groove.

• Remove dirt, debris and residues from previous seals.

• Check mating surfaces for sharp edges and burrs.

• Verify that the O-ring dimensions match the groove geometry.

• Avoid excessive stretching or twisting.

• Prevent localized deformation or folding of the ring.

• Use only installation lubricants compatible with VMQ silicone rubber.

• Ensure uniform positioning around the entire circumference.

• Control cross-sectional compression during assembly.

Incorrect positioning of a large-diameter O-ring may cause localized elastomer damage, uneven compression or loss of sealing performance.

FAQ - Frequently Asked Questions

What are the dimensions of O-ring 240x3 VMQ 70 ShA?

The O-ring has an inside diameter of 240 mm, a cross-sectional diameter of 3 mm and a nominal outside diameter of 246 mm.

What does VMQ mean in the O-ring designation?

VMQ is the standard designation for methyl vinyl silicone rubber, an elastomer used in technical sealing applications requiring flexibility and resistance to temperature variations.

Are VMQ and MVQ the same material?

VMQ is the standard material designation, while MVQ is an alternative designation encountered in commercial descriptions of silicone rubber seals. Both refer to methyl vinyl silicone rubber.

What does 70 ShA mean?

70 ShA indicates a nominal hardness of 70 units on the Shore A scale, which measures the indentation hardness of elastomeric materials.

Is O-ring 240x3 VMQ resistant to high temperatures?

VMQ silicone rubber generally provides good resistance to elevated temperatures. The exact permissible operating temperature depends on the specific silicone compound and application conditions.

Can O-ring 240x3 be used to seal large equipment covers?

Yes, it may be suitable for sealing large covers and housings when the groove dimensions, compression and operating conditions are appropriate.

Can this silicone O-ring be used with oil?

Compatibility depends on the type of oil, its additives, operating temperature and the specific VMQ compound. Material compatibility should be verified before installation.

Is VMQ suitable for dynamic sealing applications?

VMQ silicone rubber generally has lower abrasion and tear resistance than many other elastomers. Silicone O-rings are therefore usually preferred for static sealing applications. Dynamic use requires application-specific evaluation.

What is the nominal outside diameter of O-ring 240x3?

The nominal outside diameter is 246 mm, calculated from the 240 mm inside diameter and the 3 mm cross-sectional diameter.

Can this O-ring be used in food processing equipment?

Only if the specific product has the required documentation confirming compliance with applicable food-contact regulations.

Why is correct installation particularly important for large-diameter O-rings?

Large-diameter O-rings require uniform positioning around the sealing groove. Twisting, folding or uneven compression may cause localized damage and reduce sealing effectiveness.

AI Overview - Technical Summary

O-ring 240x3 VMQ 70 ShA is a silicone rubber sealing ring with an inside diameter of 240 mm, a cross-section of 3 mm and a nominal outside diameter of 246 mm. Manufactured from VMQ silicone rubber with a hardness of 70 Shore A, it provides resistance to ozone, UV radiation and atmospheric ageing. Primarily designed for static sealing of large industrial connections.