What is Varprene?

Peristaltic Pump Hoses for Food, Dairy and Cosmetic Applications

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Varprene is a proprietary name for Saint-Gobain Performance Plastics Norprene^® A-55-F material, commonly used for food, beverage and other applications involving products manufactured for use in or on the human body. We recently had a customer ask about Varprene, discovered there was little information online, and therefore this article describes Varprene along with the other peristaltic hose pump materials used for similar applications.

 

Peristaltic Pumps for Food and Pharmaceutical Applications

The Vector 2000 series peristaltic pump, due to its dry roller design, does not require a lubricant-filled case. The only lubrication required is a light coating of silicon grease to minimize the friction between the roller and hose during compression. Other types of peristaltic pumps have a fixed shoe design and require liquid glycerin lubricant to reduce friction and heat due to the compression of the hose. Thus Vector 2000 series peristaltic pumps are inherently better designed for food, dairy, cosmetic and other sensitive fluid applications because the potential for cross-contamination with a grease-lubricated design is much lower than with an oil bath.

 

Hose Materials Satisfying FDA Criteria

The FDA (Food and Drug Administration) is a government agency responsible for establishing regulations in support of safety concerning drugs, biological products, the food supply, cosmetics and related products. Title 21 CFR (Code of Federal Regulations), Section 177.2600 defines the characteristics of polymers as an “indirect food additive” for processes where rubber articles are used repeatedly. We offer three materials satisfying Title 21 CFR 177.2600: Varprene, Pharmed and Natural Rubber with fiber braiding.

 

Varprene

Varprene is the name used by Wanner Engineering for peristaltic pump hoses made of Saint-Gobain Performance Plastics Norprene^® A-55-F material. The A-55-F formulation of Norprene^® is an extruded hose material known for its resiliency and chemical resistance to sanitizers, cleaners, ozone and UV light. Varprene/Norprene^® is autoclavable.

 

While the A-55-F formulation of Norprene^® has a temperature range of –75 °F to 165 °F, that is not the temperature range suggested for use with Vector peristaltic pumps. The low end of the operating temperature range for Varprene when used in Vector peristaltic pumps is –14 °F and the maximum temperature is 185 °F.

 

It is important to note that operation of any hose material within 15 °F of its maximum operating temperature necessitates reducing the pump RPM to ≤ 20 RPM. The other special consideration with high-temperature peristaltic pump applications is that a solid metal inspection port cover replaces the standard clear acrylic inspection window.

 

Varprene/Norprene^® is a homogeneous cream-colored, extruded material having smooth inner and outer surfaces. As with all extruded hose materials, we estimate the useful life to equate to 700 to 1,000 hours of use if the pump shaft speed is ≤ 30 RPM.

 

The life cycle of extruded hoses is affected by the length of operation. Peristaltic pumps operated at ≤ 30 RPM and at lower pressures may be used continuously with the hose longevity expectation noted above. When operating at higher pressures or at a higher RPM, the usage should only be intermittent (defined as 1 hour idle after 2 hours of use). Extruded hoses such as Varprene/Norprene^® and Pharmed can only be used for pressures up to 30 PSI. They should also be used with non-abrasive, “clean” fluids and for lower suction lift requirements because extruded materials are softer and more prone to damage from hard particles.

 

Typical applications for Varprene hoses

• Butter
• Cake dough and frosting
• Caramel
• Chocolate
• Cosmetic creams
• Egg yolks with whites
• Fats
• Flavorings
• Gelatines
• Jams and preserves
• Milk
• Shampoo
• Wineries
• Yogurt

Pharmed^®

This is another Saint-Gobain Performance Plastics material having a slightly opaque beige color. The temperature range applicable to Vector peristaltic pump applications is 32 °F to 180 °F.

 

As a homogeneous, extruded and autoclavable material, the useful life equates to 700 to 1,000 hours of use if the pump shaft speed is ≤ 30 RPM.

 

In addition to satisfying FDA Title 21 CFR 177.2600, Pharmed^® is the only Vector pump hose material satisfying USP Class VI and NSF criteria.

 

USP (United States Pharmacopeia) Class VI, as it relates to Vector peristaltic pump hoses, represents testing standards to ensure there are no harmful reactions or long-term health effects associated with the hose material. NSF (National Sanitation Foundation) is an independent testing organization that establishes testing and analyzes materials as they relate to public health protection.

 

Typical applications for Pharmed hoses

• Face creams
• Latex
• Lotions
• Plasma
• Protein solutions
• Vaccines
• Vaseline

Fiber-Braided Natural Rubber

Natural rubber is an organic, sustainable polymer of isoprene obtained from rubber trees. It provides superior abrasion resistance, and the addition of a fiber-braided layer significantly increases its durability.

 

The fiber layer increases the operational pressure range to over 100 PSIG depending upon the pump model (hose size). It also doubles the lifecycle, with an expectation that the hose will last 1,500 to 2,000 hours before requiring replacement when operated at ≤ 30 RPM. The operating temperature range for fiber-braided natural rubber peristaltic pump hoses is –14 °F to a maximum of 185 °F.

 

Fiber-braided hoses are stiffer than extruded hoses and help maintain the circular hose ID, increasing suction lift capability and fatigue resistance.

 

Typical applications for natural rubber hoses

• Bentonite and carbon slurries
• Animal waste including blood, hair and bone

 Hose Barb Interface with Hoses

Tri-Clamp connections are very common for food, dairy and applications sensitive to contamination that require frequent cleaning of system components.

 

Vector peristaltic hose pumps can be supplied with Tri-Clamp, threaded, barbed or flanged connections to interface with the process piping.

 

One aspect all hose barb fittings have in common is a barbed interface with the peristaltic hose itself. Between each barb there are voids, which might be a concern for some sanitary applications. It is not that there is a significant chance of material accumulating within these voids; rather that it is an area that is not exposed to common sanitizing procedures.

 

To satisfy strict sanitization requirements such as 3-A, it is necessary to remove the hose and clean the hose and fitting separately. Oftentimes the hoses are discarded after each batch; in such cases this is not a concern.

 

The next time you have a pump application, reach out to us using one of our web-based inquiry forms, send an email or call our office. We will put our experience to work for you.