Home News A Field Guide to Kalrez Industrial Seals and O-Rings

A Field Guide to Kalrez Industrial Seals and O-Rings



The Versatility of Kalrez Industrial Seals

Welcome to the wonderful world of Kalrez O-Rings! O-Rings are seals meant to keep liquids and gases at bay within machine constructs. Kalrez brand O-Rings are the industry gold standard when it comes to proper sealing. O-rings are used throughout all facets of industry including, but certainly not limited to: the industrial sphere, life sciences, the energy, oil and gas industries, fluid power, chemical processing, and heavy equipment operations.

Kalrez O-rings compatibility potentials are innumerable; highly customizable and with the ability for prototype development, O-rings are the staple of both the past and future. O-rings come in varied properties of resistance to heat, hardness, and compression ratios. You can select an O-ring in any size to fit your unique specifications here.

Whatsmore, o-rings can be crafted to withstand varying degrees of strain, which may include vacillating temperature extremes, pressure, and tolerance stress. Unsurprisingly, without o-rings, innumerable mechanical operations would be impossible.


10 Benefits of Kalrez O-Rings

You know Kalrez is the industry staple, but do you know why? Here’s a quick briefing on why Kalrez earns its much-esteemed veneration:

  1. Resistant to 1,800+ chemicals (will not degrade as a direct chemical reaction)
  2. Staggering heat resistance up to 620°F
  3. Staying power is superior to other brands
  4. Reduces machine maintenance expenditures
  5. Augments productivity (lessens necessity to change out worn-out rings)
  6. Reduces fumage exposure
  7. Ensures process purity
  8. Tear resistant
  9. Ozone resistant
  10. Able to perform at 20°F (compared to at least 65°F for other brands)


Pretty neat, right? We think so. But, do you know which Kalrez O-ring is the exact match for what you need? Here’s a breakdown of six of our most popular models.

1. DuPont™ Kalrez® Spectrum 6375

Excelling in usage involving acids, bases, amines, steam, ethylene oxide, and characteristically hostile chemicals, the Kalrez Spectrum 6375 is called upon to handle mixed streams. The 6375 o-ring operates at 100°F higher than other brands. Chemical processors typically leverage this particular o-ring because it excels in both chemical and thermal resistance at higher temperatures.

When graded on chemical resistance the Kalrez 6375 received an A in the following chemical tests: water 437°F, glacial acetic acid 212°F, nitric acid (70%) 185°F, sulfuric acid (98%) 302°F, maleic acid 194°F, ammonium hydroxide 212°F, ethylene oxide 122°F, urea 347°F, epichlorohydrin 212°F, butyraldehyde 158°F, toluene diisocyanate 212°F, and HCFC 134a (77°F).

Read all technical information on the Kalrez Spectrum 6375.


2. DuPont™ Kalrez® 6221

The apex of handling aggressive water (WFI), the Kalrez 6221 (in white) is excellent resisting harsh chemicals and excels in keeping contaminates out of food handling services. Used frequently in steam-in-place cleaning systems, the Kalrez 6221 withstands 500°F, allowing use in stage two sterilization operations.

Swelling is a common culprit in seal futility, in addition to embrittlement and decomposition. However, the Kalrez 6221 o-ring lept past its competition in general chemical resistance testing. The Kalrez 6221 received an A in all tested chemicals and products when subjected to swelling stress. (Meaning the chemicals had little or no effect on the Kalrez 6221.)

The chemicals tested include: acetic acid, acetone, citric acid, hydrogen peroxide, isopropyl alcohol, methyl ethyl ketone, mineral oil, NaOH, nitric acid, sodium hypochlorite, soybean oil, steam (<150°C), steam (>150°C), toluene, and xylene.

Temperatures of listed chemicals did not exceed 500°F.

Read all technical information on the Kalrez Spectrum 6221.

(Take a look at the Kalrez 6230 for similar properties. The Kalrez 6230A is specifically utilized for sanitary gaskets.)


3. DuPont™ Kalrez® Spectrum™ 7075

The Kalrez Spectrum 7075 is typically used in taxing chemical and hydrocarbon processing. This o-ring is particularly effective for smaller mechanical seals. Kalrez 7075 o-rings are leveraged in seals, valves, and flanges. The 7075 model boasts an increased heat resistance of 620°F. The most notable disadvantage of the Kalrez 7075 is that it does not perform well in extreme aquatic environments. (The Kalrez 6375 o-ring is recommended for water usage.)

Additionally, the Kalrez 7075 possesses an atypically low compression set. We should mention lower compression set results are great! For you, this translates directly to bolstered sealing capacity and longer life cycle.

The Kalrez 7075 received an excellent score in testing chemical resistance to: aromatic oils, acids, bases, alcohols, aldehydes, amines, ethers, esters, ketones, steam, strong oxidizers, ethylene oxide, and hot air.

Read all technical information on the Kalrez Spectrum 7075.


4. DuPont™ Kalrez® Spectrum 7090

Engineered for applications requiring augmented hardness, the Kalrez Spectrum 7090 features compression set resistance, seal force retention, and remains viable during temperature cycling and rapid gas decompression. The Kalrez 7090 operates in both a static and dynamic environment. During testing the Kalrez 7090 operated continuously at a temperature of 614°F. (Exceeding this temperature in short bursts may be possible in the correct conditions.)

Read all technical information on the Kalrez Spectrum 7090.


5. DuPont™  Kalrez® 0090

Kalrez Spectrum 0090 is the go-to for sealants requiring superior rapid gas decompression control, high hardness ratings, and high modulus capabilities. Practical applications include downhole drilling equipment, industrial grade pumps, and valves. Already marked by the Kalrez’s brand ability to withstand 1,800 harsh chemicals, the Kalrez 0090 specializes in resisting sour multiphase fluids containing H2S.

The Kalrez 0090 operates efficiently between 40°F - 482°F.

Read all technical information on the Kalrez Spectrum 0090.


6. DuPont™ Kalrez® Spectrum 0040

Crafted exactingly for usage in low temperature conditions with antagonistic chemicals, the Kalrez Spectrum 0040 is a mainstay of the chemical transportation industry.

Read all technical information on the Kalrez Spectrum 0040.


Custom Kalrez O-Rings

Whatever your o-ring needs, we’re here to assist. Browse our extensive inventory of o-rings, and feel free to reach out to our support unit for developing o-ring prototypes or questions regarding fulfillment and support for your manufacturing needs.



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