Inputting the minimum and maximum application temperature has two impacts to the application First, for the sizing simulator will apply a coefficient of thermal expansion to the seal, based on these values. For this reason, the limits are set at a minimum of to -80˚F (-62˚C) and a maximum of 575˚F (302˚C). Second, the temperature inputs can be used as a way to select a material. The product matches (specific seal materials) will be filtered to meet the application. Elastomeric materials are available outside of the to -80˚F (-62˚C) minimum and 575˚F (302˚C) maximum.
Available seal materials are presented as options for the simulator. Seal materials offered to users are based on the user’s default location. Users from North America are offered materials available through the North American operations, while users outside of North America are offered materials offered through Parker Praedifa in Germany. Use the North American / International switch at the top to switch to the alternate material options. As Polymer Group, Seal Hardness, Fluids, Certifications are selected, the materials will filter to fewer options. Use of the Reset button will clear all prior selections.
Fluids detailed in the O-Ring Handbook are presented in a searchable format. Up to twenty fluids can be selected, and product matches are filtered to those with a compatibility rating of Fair or Satisfactory. As will all designs, it is best to perform testing with selected O-ring materials, fluids, pressures and temperatures.
Select one of the standard sealing cases. Check that the illustration below matches your application. Then select the most suitable application. This affects the recommendations for groove size, groove tolerance & O-ring compression values.
Thermal expansion can have a major effect on dimensional calculations. However, for basic calculations, it is usually not necessary to change the default settings. Even if the check box "thermal expansion & volume swelling" is unchecked, the application will use the default thermal expansion coefficient of the selected polymer group. . This means that whenever a seal polymer group is selected and the operation temperature differs from the room temperature, thermal expansion will automatically have an effect on the calculation results. When a more exact approach is required, the box can be checked and more exact thermal expansion or swelling information can be given. It is also possible to define the thermal expansion characteristics for the hardware. Note that for metal parts, the thermal expansion coefficient is usually much lower than for elastomer compounds and thus can be neglected. But for plastic housings, the thermal expansion may have a big impact on results. The thermal expansion of the hardware can be activated by selecting a material from the drop-down menu or by entering the value manually. Note that the pre-filled coefficients are only indicative and they may not match with the materials used in your application. Swelling affects gland fill calculations only. If the maximum volumetric swelling value is known, it can be entered here.
If back-up rings are used in the application, enter the number and width of the back-up rings here. This only affects the gland fill calculations. Enter this information before using the size search tool to automatically compensate for the groove width to fit the back-up ring elements. One back-up ring means that there is a back-up ring only on one side of the O-ring. Two back-up rings mean that there are back-up rings on both sides of the O-ring. Width means the width of one back-up ring element in axial direction.
Use the size search tool to search for standard O-ring and groove sizes. At first, a cross section must be entered. Generally speaking, the bigger the diameter, the bigger the cross section should be. Then select either O-ring inner diameter or a sealing case -dependent hardware diameter. The list of available choices depends on the sealing case, application and the cross section. Alternatively, the O-ring size code can be directly entered in the field and then the O-ring and groove dimensions are automatically populated.
Note that this tool uses standard tables and they may not be suitable for all applications and conditions. Therefore, the resulting values should often be considered only a starting point for application-specific fine-tuning. It is also possible to enter all the dimensional and tolerance information manually. If you change the application or back-up ring parameters after using the size search toll, please run the tool again to have these changes reflected in sizing.
This section shows the calculation results based on the given inputs. For some results, a recommendation is shown. Ideally, all results should stay within these recommendations. When a recommendation is exceeded, the application gives a yellow or red warning based on the severity. The resulting values are worst-case scenarios, combining extreme tolerance cases with extreme operational conditions. Therefore, it may sometimes be challenging to stay completely within the recommendations, especially when using very small O-rings. When this is the case, it may help to use bigger O-ring size.
"Stretch of OR inner-ø" and "Interference of OR outer-ø" results are shown in assembly conditions. Other results are shown in operating conditions. If “gap” value is negative, it means that an interference fit situation is possible (i.e. piston is bigger than the bore). Based on the application, this may be unwanted.
For “Gland fill” calculations, swelling and the back-up rings are taken into account.
Literature
O-Ring Handbook
O-Ring Guide
O-Ring Product Catalog