Category Archives: Parker Hannifin Seals

Learn more about Parker Hannifin seals, o-rings, polymer springs and much more in this collection of articles. Parker sealing products are used in a number of industries for a variety of applications, including hydraulic sealing systems.

Omega Seal Profile Replaces PSA-backed Seals

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


Omega Seal Profile: A More Robust PSA-Backed Sealing Solution

Standard D-Profile - Omega Profile SealsCustomers often call with various sealing challenges. But sometimes their dilemmas can be solved with more robust solutions instead of direct replacements. For example, when a customer is having issues with a PSA-backed hollow seal that keeps peeling away from the bottom surface.

If you need to seal a box with a lid, you may need a 4-corner gasket to seal the contents from dirt and moisture. If you use a solid gasket, the compression force may be too great to effectively close the lid. Using a hollow seal reduces the compression force by orders of magnitude, but it comes with its own set of challenges.

A hollow seal for a box will most often seal between two flat surfaces. The bottom surface will be flat for adhesion to the box, while the top surface is curved to engage the lid as it is seated on top of the seal. However, the disadvantage of this design is the tendency of the flat portion to lift off the bottom surface. Figure 1 illustrates this phenomenon with standard Parfab profile D015.

Omega Seal Replace Hollow-D profile w/ 25% compression
Figure 1: Hollow-D profile D015 with 25 percent compression.

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TetraSeals: Alternate Sealing Solution

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


TetraSeal: An Alternate Sealing Solution When an O-Ring Isn’t Working

Parker TetraSeals

Our applications engineering team takes more than a few calls each month where the O-ring is leaking, either immediately or after just a short time in service. Once we drill down to the details, we learn the failure mode is an improperly sized groove and O-ring. It isn’t all that uncommon for a groove to be cut in a flange and a novice designer learns the hard way that standard O-rings cannot fit in just any groove geometry. For hardware that has already been machined, frustration ensues as the caller learns the O-ring solution requires tooling. Tooling can have a lead time of at least a month to cut and can cost thousands of dollars. Parker offers a TetraSeal® solution, which often does not require tooling and can be made of many of the same materials used for O-rings.

Benefits of TetraSeals

The TetraSeal is a circular precision-cut seal with a square cross-section. Unlike O-rings which require a unique mold for each material family and size, TetraSeals are extruded, cured and machine cut to the target thickness. Our manufacturing facilities in both Spartanburg, South Carolina and Goshen, Indiana are tooled in a variety of interchangeable extrusion dies, making this type of seal an easily sourced seal solution without the lead time and cost of a custom molded O-ring.

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Poppet Seals Control Fluid or Gas Flow

Poppet Seals for Demand Flow Regulators

Avoid Leakage and Support a More Accurate System
Poppet SealsThere are many applications in industrial settings where fluid must be sealed and released in calibrated quantities. Some examples include pressure regulators, relief values, fuel nozzles, or gas metering. Specifically a demand flow regulator is designed for use with various industrial instruments and uses a pump to draw the calibration of gas. It is crucial that there is no leakage of the fluid for the system to operate properly.

Parker Composite Sealing Systems Division designs different poppets to help control leakage in flow control applications. Our poppet is used to help keep the demand flow regulators in the “closed” position. And when the user “demands” gas flow, a diaphragm pushes down on the seat stem of the Poppet to help monitor the flow of gas.

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Innovative Solutions Improving Seal Retention

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


Seal Retention - Pre-applied PSA

We receive many requests from customers asking for recommendations on how to retain seals in an application. One of the most popular “quick fixes” is to apply liberal amounts of adhesive to a standard O-ring type product without respect to groove shape or sealing function. However, Parker OES provides a wide array of sealing technologies, offering innovative solutions to accommodate the challenging and vast sealing needs of our customers.

Replacing RTV with Pre-Applied PSA

A customer had been using a standard O-ring product on an outdoor electronic device. This part was sealing the external edge of the enclosure and meant to keep out water and dust. The enclosure was plastic injection molded so this extreme edge had irregular geometry to accommodate the molding process. The original proposal was to shove O-ring cord in place and adhere it down with RTV (Room Temperature Vulcanization) so that it did not fall out during assembly. This left a rust colored stripe exposed on a  consumer device due to fitment issues. Parker’s proposal was to replace the O-ring cord with a custom hollow extrusion that fit the available space and allowed complete closure, thus not exposing the seal to be visible. The RTV process was replaced with PSA (Pressure Sensitive Adhesive) that was preassembled to the seal and allowed for quick and clean placement during assembly and retention for any maintenance needed.

Innovative Solutions Improving Seal Retention, Hollow Teardrop Profile Seals, O-Ring & Engineered Seals Division

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O-Ring Selection Made Easy

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


O-Ring Selection Made Easy with the Parker O-Ring Selector

O-Ring Selector Tool - O-Ring Selection

Two things are equally important for the reliable performance of an O-Ring seal: the right size and the right material. Parker’s new O-Ring Selector is an engineering tool that enables users to make the right material and size selections easily, quickly and reliably – in a single application. The accuracy of the results ensures the desired performance of the O-Ring in the subsequent application. This is primarily based on the fact that both functionalities – the material selection and the O-Ring size calculation – are closely interlinked. This achieves a new quality in calculating the total sealing system.

Overview of the O-Ring Selector

The Parker O-Ring Selector is divided into three main sections:

  • Service Conditions & Material Selector
  • Size Selector
  • Notes

O-Ring Selector Tool - O-Ring Selection - Service Conditions & Material Selector

The Service Conditions & Material Selector section is focused on mapping the material-related application conditions. Entering the operating temperature range, the desired polymer family and/or material hardness will take the user to the suitable material selection. The Advanced Material Selector enables experienced users to specify the operating conditions in even greater detail. Here the medium to be sealed can be selected from a database containing 2,500 media. In addition, a search for required approvals and conformities can be run.

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Parker’s Rapid Prototype Program

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


Rapid Prototype ProgramThe O-Ring & Engineered Seals Division is now offering a rapid prototype program for solid and hollow spliced O-rings that will reduce lead times on small orders to improve sample and trial testing on enclosure projects. The program provides spliced rings available in a variety of cross sections and can be purchased in either solid or hollow profiles.

Spliced ring sizes

In the event that enclosure tolerances are large or the available compressive force is low, Parker engineers can design a custom hollow seal to help absorb large tolerances while providing very low compressive force compared to solid cord. Spliced rings with large inside diameters up to 95” are available in silicone and nitrile materials. Rings with inside diameters up to 57” are available in fluorocarbon. Cross sections of .070”, .103”, .139”, .210” .250” are regularly stocked and available to splice to the ring ID needed. The chart below outlines the current compounds, cross sections, and diameters available under the program.

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Selecting the Right O-Ring Squeeze Ratio

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


One of the decisions equipment designers need to make when installing O-ring seals in their applications is how much the O-ring will be squeezed by its mating hardware to create an effective seal.

What is O-ring squeeze

O-Ring Squeeze RatioSqueeze is a ratio of the amount of deformation applied to the seal expressed as a percentage of the free-state cross-sectional thickness. Deforming the seal cross-section “energizes” the elastomer matrix much like compressing a spring; the inherent elasticity of the rubber material causes it to push back against the mating components. This contact force blocks the passage of liquids, gases and dry powders, preventing them from flowing between the rubber seal and the mating hardware.

The greater the squeeze, the more force is applied against the hardware and the tighter the seal. But that doesn’t necessarily mean that designers should always specify the most squeeze (assuming they knew what that level was or why it was “the most”). There are a number of factors to consider, which include:

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How To Install an O-Ring in any Application

O-Rings continue to be the most widely utilized sealing product.  While the ‘Donut’ shaped profile has by and large been kept intact since their inception, continued elastomeric development has pushed o-ring temperature and chemical compatibility to limits unimaginable several decades ago.

Typically, O-Rings fail due to adverse effects of a number of factors, from improper installation and lubrication to incorrect size and design.  The collection of videos below will help you minimize installation errors that may lead to failure (be sure to bookmark this page for future reference).


How To Install an O-Ring – Standard Male Gland

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Continuous Molding Enables Production of Large-Size Elastomer Seals

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


Continuous Molding - Vulcanization of Large Size O-RingsPrecision O-rings are manufactured by vulcanization in a closed mold using compression or injection molding. This makes it possible to produce O-rings in relatively small manufacturing tolerances and with good surface quality according to ISO 3601-1 and ISO 3601-3. Due to defined vulcanization parameters, precision O-rings exhibit consistently high mechanical properties across the entire circumference. This high quality level is an indispensable prerequisite for achieving consistently good sealing effects over a long period of time.

However, up to now, this production technology has been regarded in the sealing industry as not being economically feasible for O-rings in very large dimensions due to the enormous work and related costs involved in making extra-large molds. In addition, such large molds are extremely difficult to handle and therefore cannot be accomplished by many seal manufacturers.

Advantages of Continuous Vulcanization

The innovative manufacturing technology of continuous vulcanization used by Parker Prädifa, which does not involve failure-prone joints, enables the cost-efficient production of precision-quality O-rings with high mechanical load resistance in nearly any desired diameter. The technical properties of continuously vulcanized O-rings are comparable with those of O-rings produced by conventional compression molding. As a result of being molded, these XXL O-rings are quality products for challenging applications.

The surface qualities and tolerances correspond to those in ISO 3601:2012. However, this standard only covers cord thicknesses of up to 8.4 mm. To ensure that customers receive reliable and consistently high-quality O-rings where cord thickness is >8.4 mm, Parker Prädifa has developed an in-house standard based on ISO 3601:2012.

Customer-specific geometries for static and dynamic applications
In addition to precision-quality XXL O-rings, Parker Prädifa offers the development and production of customer-specific geometries in large diameters. A wide range of materials is available according to the application requirements.


Case study: Sealing solution for centrifuge (pharmaceutical industry)

Continuous Molding - Vulcanization of Large Size O-Rings

The challenge >> In the large-scale industrial production of semi-synthetic antibiotics, up to 500,000 liters of antibiotics are produced per batch. For such large-scale production to be economically feasible equipment of corresponding dimensions is required. In addition to large fermenters with diameters of several meters in which the biotech antibiotic is bred, centrifuges of similar dimensions are utilized to separate the antibiotic from process agents. Leakage must be prevented at all cost for safety and economic reasons. A leaking centrifuge might contaminate the antibiotics, resulting in high financial losses or, worse yet, in health and environmental hazards.

The solution >> Parker Prädifa was involved in the project at an early stage to develop a reliable sealing solution. The utilization of continuously vulcanized, i.e. jointless precision O-rings ensures the requisite reliability. Besides the seal design, the compound properties, particularly temperature and media resistance, play a key role. In addition to permanent temperatures of 250 °C, the seal has to withstand the aggressive media used in antibiotics production. The Parofluor® (FFKM) compound V8920 was selected as the suitable material for this application.


Case study: Lip seal ring for lithography system (semiconductor industry)

Continuous Molding - Vulcanization of Large Size O-Rings

The challenge >> The development of a new lithography system for semiconductor manufacturing posed the challenge of sealing two halves of a housing. Due to the tolerance situation in producing the respective housing halves, there was a risk of a gap of up to 0.5 mm occurring between the two halves in the assembled housing.

The solution >> In sealing technology, the gap dimensions to be bridged are typically between 0.05 mm and 0.25 mm. As larger gap dimensions available for sealing in the groove in this application could not be reliably sealed, or only by entailing a higher risk of leakage, with a solid seal such as an O-ring, a conventional O-ring sealing solution was not selected here, but a profile seal featuring a lip design. This seal was developed using Finite Element Analysis (FEA) to ensure reliable sealing of large gaps and tolerance variations in the seal groove between the two halves of the housing. In addition, the shape of the seal prevents twisting during installation and reduces the required assembly forces.
In the selection of the seal compound, high purity requirements had to be considered. Due to specific post-curing processes, the FKM compound V0747 with low outgassing properties achieves outstanding results.

More information
EMG Report 07/2017, Page 22
Brochure: XXL Size Seals and Molded Parts


This article was contributed by Stefan Reichle, Market Unit Manager Indsutry, Engineered Materials Group Europe, Prädifa Technology Division.

Source: http://blog.parker.com/continuous-molding-enables-production-of-large-size-elastomer-seals-in-precision-quality

3 Guidelines to Ensure Proper O-Ring Installation

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.


Incorrect O-ring installation can lead to assembly damage causing leakage during the first pressure test. If the system does not pressurize properly, the entire piece of equipment should be disassembled and seals must be replaced. Depending on when this test occurs, multiple manufacturing steps could be in between the seal installation and the first step where leakage can be identified. If O-ring damage happens with high frequency, you could be wasting time and money on seal replacement. Luckily, there are some easy steps that can be followed to help prevent this from occurring. Parker’s recommended guidelines for installation include always using lubrication, good gland design, and ensuring correct sizing.

Lubrication Makes Installation Easier

O-Ring Installation - Parker O-LubeUsing lubrication is an essential facet of proper installation. Lubrication reduces surface friction between the O-ring and mating surfaces, allowing the O-ring to seat in the groove with very little difficulty. In male and female radial seals, lubrication will reduce installation force and create a smooth transition as the piston is inserted in the bore.

Choosing the proper lubricant requires careful consideration of your system. You must ensure the lubricant choice is compatible with the material being used, suitable for the temperature range of the application, compatible with the system fluids, capable of producing a high surface tension film, and does not clog system filters.

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