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Two things are equally important for reliable performance of an O-ring seal: the right size and the right material. Parker’s new O-Ring Selector is an engineering design tool that enables users to make the right material and size selections easily, quickly and reliably – in a single application. This post explains how to design the sealing system using the “Size Selector.”
See also blog post:
The “Size Selector” calculates the installation conditions and the suitable O-ring. It is divided into three segments: “Hardware Configuration,” “Sizing Selection” and “Results” (of the calculation).
The “Hardware Configuration” segment is used for a detailed description of the sealing system. The user can choose between two radial (Piston und Rod Seal) and two axial (Internal and External Pressure) sealing systems. Subsequently, these choices can be specified in greater detail by selecting liquid systems or gas/vacuum systems. The selection of the various options is intuitive due to the clear, graphic presentation of the individual sealing systems.
“Hardware Configuration” also includes a look at the diverse thermal expansion coefficients of the hardware components. Representative values, e.g. for steel or aluminum, are available here. Of course, if known precisely, these values may also be entered manually to parameterize the sealing system with maximum accuracy. Chemical swelling of the seal itself may be included in the calculation as well.
The “Sizing Selection” segment is focused on the comprehensive calculation of the system to be sealed. If known, all values such as O-ring diameter, piston diameter, etc. can be entered manually. Alternatively – if complete information is not available – an automatic parameterization of the sealing system can be performed via the selection of the O-ring diameter and (for instance) the targeted piston diameter. All the individual values calculated this way can be adjusted manually in a second step and their effects on the functionality of the sealing system reviewed. The toleration of the hardware components can be adjusted to the user’s application as well to satisfy the various quality requirements in the manufacturing process.
The “Results” segment displays the calculated results in a structured manner. For the key results parameters, the recommendations are shown according to ISO/Parker specifications. In addition, minimum and maximum tolerations for the results parameters are indicated. A simple visual check if the calculated sealing system corresponds to ISO/Parker recommendations is made using color codes: green stands for “Recommended,” yellow for “Warning” and red for “Critical.”
Users can enter their own comments on the calculations made in “Notes.” After the review of the sealing system has been completed, the data obtained can be converted into a PDF.
>>> Start imperial version >>> Start metric version
Additional information:
Posted by:
Dr. Heinz-Christian Rost Technology & Innovation Manager Engineered Materials Group Europe, Prädifa Technology Division
O-Ring Selection Made Easy with the Parker O-Ring Selector
How to Select the Right O-Ring Material with the Parker O-Ring Selector
17 May 2018
Read More
Zwei Dinge sind für die zuverlässige Funktion einer O-Ring-Dichtung gleichermaßen wichtig: die richtige Größe und der richtige Werkstoff. Der neue O-Ring-Selector von Parker ist ein Konstruktions-Tool, das es dem Anwender ermöglicht, einfach, schnell und zuverlässig die geeignete Material- und Größenauswahl zu treffen – in einer einzigen Anwendung. In diesem Beitrag wird die Auslegung des Dichtsystems mit Hilfe des „Size Selectors“ erläutert.
Siehe auch Blog Posts
Im Bereich „Size Selector“ (Größenauswahl) erfolgt die Berechnung der Einbausituation und des geeigneten O-Rings. Dabei unterteilt sich der „Size Selector“ in drei Segmente. Die „Hardware Configuration“, die „Sizing Selection“ und die Ergebnisse der Berechnung („Results“):
Im Segment „Hardware Configuration“ erfolgt eine detaillierte Beschreibung des Dichtungssystems. Dabei kann zwischen zwei radial abdichtenden (Piston und Rod Seal) und zwei axial abdichtenden (Internal und External Pressure) Dichtungssystemen gewählt werden. Diese lassen sich dann jeweils weiter durch die Auswahl von Flüssigsystemen oder Gas-/Vakuumsystemen spezifizieren. Die Auswahl der verschiedenen Optionen ist aufgrund der klaren graphischen Darstellung der einzelnen Dichtungssysteme intuitiv.
Die „Hardware Configuration“ schließt auch die Betrachtung der unterschiedlichen thermischen Expansionskoeffizienten der Hardware-Komponenten mit ein. Hier kann auf repräsentative Werte beispielsweise für Stahl oder Aluminium zurückgegriffen werden. Bei genauer Kenntnis können die Werte aber natürlich auch manuell eingetragen werden, um eine möglichst genaue Parametrisierung des Dichtungssystems zu erreichen. Auch kann die chemische Quellung der Dichtung selbst in der Kalkulation berücksichtigt werden.
Das Segment „Sizing Selection“ konzentriert sich auf die umfassende Berechnung des abzudichtenden Systems. Wenn bekannt, können alle Werte wie O-Ring-Durchmesser, Kolbendurchmesser etc. manuell eingetragen werden. Es kann jedoch auch – bei nicht vollumfänglicher Informationslage – über die Auswahl des O-Ring- Durchmessers und beispielsweise des angestrebten Kolbendurchmessers eine automatische Parametrisierung des Dichtungssystems durchgeführt werden. Alle so berechneten Einzelwerte können in einem zweiten Schritt manuell angepasst und die Auswirkung auf die Funktionsfähigkeit des Dichtungssystems betrachtet werden. Die Tolerierung der Hardware-Komponenten kann ebenso dem realen Fall angepasst und somit den unterschiedlichen Qualitätsanforderungen im Herstellungsprozess Rechnung getragen werden.
Im Segment „Results“ werden die kalkulierten Ergebnisse strukturiert dargestellt. Für die wichtigsten Ergebnisparameter werden Empfehlungen (Recommendation) gemäß ISO-/Parker-Spezifikationen dargestellt. Weiterhin werden Minimal- und Maximal-Tolerierungen für die Ergebnisparameter angezeigt. Eine einfache visuelle Überprüfung, ob das kalkulierte Dichtungssystem den ISO- / Parker- Empfehlungen entspricht, erfolgt über eine entsprechende farbige Kennzeichnung: grün steht für „Empfehlung“ („Recommended“), gelb für „Warnung“ („Warning“), rot für „kritisch“ („Critical).
Eigene Kommentare zu den durchgeführten Kalkulationen können im Bereich „Notes“ erfasst werden. Ist die Betrachtung des Dichtungssystems abgeschlossen, können die ermittelten Daten in ein PDF konvertiert werden.
>>> Metrische Version starten >>> Zöllige Version starten
Weitere Informationen:
Blig: O-Ring Auswahl leicht gemacht mit dem Parker O-Ring Selector
Blog: O-Ring-Werkstoffauswahl mit dem Parker O-Ring Selector
www.parker.com/o-ring-selector
Ein Beitrag von
Dr. Heinz-Christian Rost Technology & Innovation Manager Prädifa Technology Division
O-Ring Auswahl leicht gemacht mit dem Parker O-Ring Selector
O-Ring-Werkstoffauswahl mit dem Parker O-Ring Selector
Customers 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.
Figure 1. Hollow-D profile D015 with 25 percent compression.
In the analysis shown in Figure 1, the bowing is 0.030 inch at its highest point. Due to this tendency to bow upward, it is necessary to use Pressure Sensitive Adhesive (PSA) backing to keep the bottom surface in place during compression. However, due to the bowing of this surface, this stresses the PSA backing every time the seal is compressed. This can cause the PSA backing to eventually peel away. When this happens, the seal can also leak due to lack of seal contact on the bottom surface.
To address this issue, Parker offers the Omega seal profile, which has a hump in the middle of the flat portion to reduce bowing as the seal is compressed.
Figure 2 shows Omega seal profile W034. Like the D015 profile, it is also 0.500 inch high, and is compressed 25 percent.
Figure 2. Omega seal profile W034 with 25 percent compression.
As shown in Figure 2, the bowing of the bottom surface has been reduced from 0.030 inch to 0.004 inch, which greatly reduces peeling stress when PSA backing is used.
Figure 3 illustrates the standard profiles that we offer for the Omega seal profile.
Figure 3. Standard Omega seal profiles.
They are also available in a variety of different materials. They can be extruded as cord stock, or supplied as spliced four-corner gaskets for your particular lid or door sealing application.
For more information, visit Parker O-Ring & Engineered Seals Division online and chat with our experienced applications engineers.
This article was contributed by David Mahlbacher, Parker O-Ring & Engineered Seals Division, product design engineer for general industrial/consumer/on-shore oil & gas.
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10 May 2018
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.
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.
The manufacturing process for TetraSeals includes two dimensions on the cross section: a cut and a width. However, this methodology is used to achieve other seal profiles as well. The flexibility on the sizing of precision cut seals allows us to change the square to a rectangle, or other configuration, as an alternate seal solution if it better suits the preexisting groove. This customization can be a great alternative for unconventional groove profiles where an O-ring simply will not work. One common example of an unsuitable groove geometry is having the width too narrow for the depth. Using a seal with a round or square cross-section means choosing proper seal compression at the risk of overfilling the groove or, selecting a smaller cross-section for proper volume fill but sacrificing with too low compression. Both of these options can result in leaking or shortened seal life.
Additional benefits to TetraSeals, and other precision cut geometries are the absence of typical molding surface anomalies (such as parting line flash, non-fills, and dirty mold.) TetraSeals have a smooth, homogenous, radial sealing surface resulting from the extrusion process. Parting line disruptions can be problematic in sensitive radial sealing applications, making the TetraSeal an appealing solution.
TetraSeals can be made with an inner diameter ranging from 0.188 up to 18.000” (4.78 to 457.20 mm) and a thickness of 0.066” up to 0.265” (1.68 to 6.73 mm). In addition, the seals can be made as a direct replacement for many AS568 sized O-rings. Common materials include:
Polyacrylate & Ethylene Acrylate
EPDM
Nitrile and HNBR
Silicone
Fluorocarbon
For more information on TetraSeals or other custom sealing solutions, visit Parker O-Ring & Engineered Seals Division and chat with an engineer today!
*TetraSeal is a registered trademark of Parker Hannifin Corporation.
This article was contributed by Dorothy Kern, applications engineering manager, Parker O-Ring & Engineered Seals Division.
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The manufacturing process for TetraSeals includes two dimensions on the cross section: a cut and a width. However this methodology is used to achieve other seal profiles as well. The flexibility on sizing of precision cut seals allow us to change the square to a rectangle, or other configuration, as an alternate seal solution if it better suits the preexisting groove. This customization can be a great alternative for unconventional groove profiles where an O-ring simply will not work. One common example of an unsuitable groove geometry is having the width too narrow for the depth. Using a seal with a round or square cross section means choosing proper seal compression at the risk of overfilling the groove or, selecting a smaller cross section for proper volume fill but sacrificing with too low compression. Both of these options can result in leaking or shortened seal life.
Additional benefits to TetraSeals, and other precision cut geometries, are the absence of typical molding surface anomalies (such as parting line flash, non-fills, and dirty mold.) TetraSeals have a smooth, homogenous, radial sealing surface resulting from the extrusion process. Parting line disruptions can be problematic in sensitive radial sealing applications, making the TetraSeal an appealing solution.
TetraSeals can be made with an inner diameter ranging between 0.188 up to 18.000” (4.78 to 457.20 mm) and a thickness of 0.066” up to 0.265” (1.68 to 6.73 mm). In addition, the seals can be made as a direct replacement for many AS568 sized O-rings. Common materials include:
Two things are equally important for reliable performance of an O-ring seal: the right size and the right material. Parker’s new O-Ring Selector is an engineering design tool that enables users to make the right material and size selections easily, quickly and reliably – in a single application. This post explains how to select a material using the “Service Conditions & Material Selector.”
See also Blog Post: “O-Ring Selection Made Easy with the Parker O-Ring Selector”
Selecting the right material for a specific application is a central step in assuring the functionality of an O-ring in the system to be sealed. The “Service Conditions & Material Selector” is focused on mapping the material-related application conditions.
The “Service Conditions & Material Selector” is used to define the application conditions. The operating temperature range is the minimum input required before the subsequent calculations of the installation conditions and O-ring dimensions can be performed in the “Size Selector.” If already known, the desired polymer group and hardness of the material can be entered here as well.
When an entry is made into a data field the suitable sealing materials will automatically be displayed under “Product Matches. The desired material can be chosen by clicking "Select"
This is where users can describe the application in even greater detail. In the “Filter by Fluid Compatibility” search field, a wide range of media can be selected and combined as appropriate. The O-Ring Selector has access to a database with more than 2,500 different media for this purpose.
Required approvals and conformities can be selected by means of an appropriate filter as well. The search can either be sorted by groups or a specific certificate can be selected under “Individual Certifications” ranging from AM, DBL, FDA, ISO, MIL through to WL certificates.
To meet specific requirements – such as the recognition of installed O-rings on assembly lines – available materials can also be filtered according to their colors.
More information:
Blog: O-Ring Selection Made Easy with the Parker O-Ring Selector
Posted by
Dorothy Kern Applications Engineering Team Leader O-Ring & Engineered Seals Division
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