Selecting the Right Seal Material the Easy Way

August 7th, 2020 by

With the range of different materials available for seals, choosing the right seal material can seem intimidating.  In this blog, we directly address this issue in a simple manner. Here is how you can take the help of the acronym ‘TEMP’ to choose the correct material for an application:


  1. “T”  for Temperature

Different types of seal material offer a different range in temperature,from low to high.  Below are some popular seal materials offer the following ranges (Fahrenheit):

  • EPDM (EPM) -70 to 250
  • Fluorosilicone (FVMQ)  -100 to 350
  • Nitrile (NBR)  -30 to 250
  • Silicone (VMQ)  -60 to 400
  • Fluorocarbon (FKM) -15 to 400


  1. “E” for Environment

Seals are bound to be exposed to all types of environments.For instance, if the environment involves exposure to sunlight, EPDM is a good choice.  However,  in this type of environment, you would want to avoid the use of Nitrile in direct sunlight.


  1. “M” for Media

When selecting a compound, it is crucial to consider the media that will come in contact with the seal.  For example, Nitrile is known to perform very well with oils. However, it is best to avoid natural rubber with oils.


  1. “P” for Pressure

Pressure has to be considered an important part of the equation as well. One,  consider hardness (durometer), as it may be required where there is a large gap between the mating parts in a static application or to resist extrusion in dynamic designs.

Second, compare the at-rest vs. operating conditions to get a working idea of the long-term compression set properties of a given material.  When it comes to hardness and compression set, properties will vary among the elastomers and within the family of each one as well.

When picking a seal for an application, finding the best possible sealing material is the key. Always remember, there will be variations in performance within each family of rubber materials.  Although this article doesn’t touch on 100% of the factors to consider, we hope the introduction of TEMP will give you a headstart about your selection.


At Harkesh Rubber, we have a wide range of elastomers to fit the needs of your ‘TEMP’ requirement.  In addition to the TEMP acronym, our team of application engineers have extensive experience in engineering custom solutions as per your requirements.  Email us at [email protected] or give us a call +91-22-40060400 to place an inquiry.



Increasing Demand for Medical Grade Seals To Cope with COVID-19 Crisis

June 30th, 2020 by

The influx of coronavirus patients has caused the medical industry to heavily rely on the production of rubber parts and seals to cope with this current healthcare crisis. To be eligible for use in healthcare, these medical-grade seals have to meet high FDA and ISO standards, as well as undergo rigorous testing.

Medical grade seals are critical in a wide range of life-saving and health improving applications that have enhanced the medical industry as a whole. Let’s take a closer look at how these seals and devices are being utilized during this health crisis now.


Personal Protective Equipment


The outbreak of the COVID-19 virus has led to a drastic increase in the demand for Personal Protective Equipment (PPE) in the medical industry. Medical grade seals play a huge role in the effectiveness of PPE where there is a significant requirement for sealing against harmful bacteria, viruses, and other pathogens to protect healthcare workers and their patients from being infected and infecting others. At the moment PPE is necessary for reducing the spread of COVID-19


Medical grade seals are essential for proper shielding and protection against contamination. For long term usage, advanced protective gear that depend on medical-grade seals include:


  • Powered and supplied air respiratory protection
  • Vented
  • Eyeshields
  • Half/Full face respirator


Ventilators and Medical Devices


Other medical equipments that have high utility at the moment are ventilators and testing devices. This medical equipment require many rubber parts and seals for engineering. Medical grade seals in ventilators and other equipment must be biologically compatible with the environment to comply with FDA regulations and to be suitable for patient use.


Biocompatibility is a term used to describe the ability of a material to perform properly by exhibiting superior compatibility with human tissue and body fluids and an extremely low tissue response when implanted. For example, silicones are odorless and tasteless, they do not support bacteria growth and stain or corrode other materials. In ventilators, this is extremely important to avoid further complications and disruptions with treatment.


In addition to producing parts and seals for ventilators and testing devices, Harkesh Rubber medical seals are also designed for a variety of other medical applications that are still needed right now, such as medical pumps, IV components, feeding devices, and implants.


Harkesh Rubber has experience in designing and a broad range of medical rubber components for use in pharmaceutical manufacturing, diagnostic and surgical instruments, and other non-implantable medical devices. Our team of application engineers have extensive experience in engineering custom solutions for many different medical/life science technologies. Get in touch with our team.



How to Maintain Rubber Seals?

March 5th, 2020 by

With time, industrial-grade rubber seals require time-to-time maintenance for extended shelf-life. Generally, rubber seals undergo stress through various external factors that speed up the degradation process.

Rubber seals are subjected to rigorous tension in industries like aerospace, automotive & nuclear. The deterioration of these industrial rubber items can be considerable over time. However, the right rubber maintenance techniques will increase the serviceability of certain polymer types and rubber seals.

Some rubber seals may require certain essentials, while other rubber seals may require a combination of products and techniques, depending on the circumstances and the type of rubber involved.

These are general guidelines and specific solutions might be required depending on the Polymer in use.


1)  Use appropriate packaging for storing the seals

Rubber Seals should be stored in a way where they are not exposed to direct sunlight. Exposure to sunlight can lead to degradation and change in the shade of coloured products.

Harkesh Rubber parts are always supplied in UV-protective packaging.


2) Ensure storage at Room temperature

On many occasions without realization, seals are stored very close to the operational workshop where the temperatures may be elevated. Even though synthetic rubbers can withstand elevated temperatures it may have a degrading effect on the seal if it is left unprotected. It is best to store the seals at room temperature or below 40 Deg C, whichever is lower.


3) Scrub and clean

Scrubbing the rubber seal will not only clean off excess dirt and improve the seals’ aesthetics, but also help in preventing future wear and tear, as dirt scrapes off the rubbers surface through constant friction. 

Heavier levels of dirt require the application of diluted bleach. After rinsing the dirt, wipe the rubber seal and allow the rubber seal to dry thoroughly. 


4) Use a rubber conditioner

Rubber conditioners are essential as they prevent the rubber seals from drying and protects it from all kinds of weather effects/influences. Apply the rubber conditioner thoroughly and wipe off the excess conditioner once the rubber seal is completely saturated.

 Harkesh Rubber has 35 years of quality experience in the rubber seal industry. Our high-performance rubber seals promise excellent durability and long life. We also offer customized solutions with innovative product development to deliver precise rubber sealing solutions.



HNBR seals – Pushing Boundaries for the Energy, Oil, & Gas Industry

May 10th, 2019 by

When it comes to aggressive EOG  environments that require extreme reliability, longevity, and durability, one elastomer comes to mind: Hydrogenated Nitrile Butadiene Rubber (HNBR). HNBR is renowned for its durability and retention of properties after overtime exposure to external elements like heat, oil, and chemicals that tend to weaken the durability of rubber seals.


Properties of HNBR


Hydrogenated Nitrile Butadiene Rubber (HNBR), is a variant of nitrile rubber (NBR) that has been hydrogenated to give it enhanced mechanical characteristics and, help in increasing resistance to wear and tear. The properties of hydrogenated nitrile rubber (HNBR) depend upon the acrylonitrile content (ACN) and the degree of hydrogenation of the butadiene copolymer. The fluid and chemical resistance improves as the ACN content is increased. The preceding improvements to the material properties over that of nitrile rubber (NBR) include greater thermal stability (up to 149°C/300°F, with short periods at higher temperatures), broader chemical resistance, and greater tensile strength.


Benefits of HNBR over the standard Nitrile and Fluorocarbons

1. HNBR Seals have enhanced resistance to environments that are prone to ozone and weathering, industrial lubricants, amine-based corrosion inhibitors, sour gases (H2S), and hot water/steam (150°C).

2. Maximum operating temperature +56°F (180ºC) in oil +320°F (160ºC) in air.

3. Minimum operating temperature -25ºF (-26°C) special grades –50°F (-45°C)

4. Minimum operations are much more competitive compared to existing technologies and lead to cost reducing, technical parameters improving, also strength increasing, and the better and more qualitative product.

5. Excellent aliphatic (not aromatic) hydrocarbon resistance.

6. Fit for use in methanol and sour environments, (up to 5% Hydrogen Sulfide)


Application Advantages of HNBR Seals in the Energy, Oil, & Gas Industry

HNBR seals should be considered over standard Nitriles and Fluorocarbon seals in selected applications for the following advantages:


Improved High-temperature Resistance


HNBR seals have excellent oil and fuel resistance along with superior mechanical properties and can sustain higher operating temperatures; up to 356ºF when immersed in oil.  Based on the compound formulation, standard nitriles can endure a temperature ranging between 200° and 300°F. Fluorocarbons in hot water/steam tend to dissolve its mechanical properties.


Resistance to Sour Crude


Oil and gas that contains hydrogen sulfide (H2S) can cause a substantial decrease in tensile, elongation and hardness properties in standard nitrile
and fluorocarbon seals. Tests conducted have proved that HNBR seals promise stronger resistance over standard nitriles and fluorocarbon when directly in contact with heat, aggressive fluids, and corrosive chemicals.
Explosive Decompression Resistance


The compression-set resistance of HSN at high temperatures (such as 302°F) is much better than standard nitriles. Fluorocarbons show signs of compression at temperatures as low as 0°F.


Resistance to Corrosion Inhibitors


Corrosion inhibitors with standard nitriles and fluorocarbons create increased elongation, loss of elasticity and rigidity. On the other hand, HNBR seals have a higher resistance to a variety of common corrosion inhibitors.


Resistance to Explosive Decompression


Explosive decompression occurs when gas at high pressure permeates into the elastomer. Nitriles and fluorocarbons have shown lesser resistance to high-pressure CO2, as compared to HNBR.


Cost-Effective Bridge Between Nitrile Rubber (NBRs) and (per) Fluoroelastomers (FMKs)


HNBR elastomers offer optimum performance at a cost between nitrile rubber (NBRs) and (per) fluoroelastomers (FMKs). HNBR seals bridge the gap between the two elastomers in many areas of application where resistance to heat and aggressive media are required simultaneously.


HNBR seals boast of invaluable properties like high durability, tensile strength, and outstanding abrasion resistance that push the performance boundaries of elastomers in the aggressive EOG environment, therefore, giving impetus to the keep up with the continuous innovation in the Energy, Oil, & Gas Industry.