Trunnions

A trunnion is designed to a standard. A standard trunnion can have associated ancillaries, which are themselves standards. For instance, a trunnion standard XTT06-Base ELL and Pipe Support Variable NPS 2-36, requires a reinforcing pad where it is welded to the pipe. This pad is added to the design as a standard general ancillary XAT05-Reinforcing Plate cut from pipe.

Special notes: regarding reinforcing plates for trunnions

1. A plate is cut from an elbow of the same size and is itemized as extra material on the isometric drawing.

2. To get the best graphical representation of the plate and trunnion in Design, set Holes On and Arctol = 1.

It is also possible to create just a trunnion branch (Create > Trunnion). This is a piece of tube (a new branch is created in the model), that can also have ancillaries associated with it (for example a u-bolt).

To create a standard trunnion:

3. Select the Trunnion icon from the tool bar or select Create > Trunnion... from the main menu.

   The Trunnions form is displayed.

   

4. Enter the name of the support to be created. You can also use the auto-naming feature by clicking on the AutoName icon .

5. Select the support type required.

   At any time when the Trunnions form is displayed, you can click on the View button to see the engineering drawing corresponding to the selected support.

   The icon allows you to create a Trunnion from an existing Preliminary Support. Refer to Convert an Existing Preliminary Support into an MDS Support for further information.

6. Click on OK to display the trunnion creation form.

   Refer to the MDS Trunnion Defaults form in the MDS Administrator Guide for further information.

Example:

In this example you will create support type XTT04 using the name PS14721.

The Trunnion Creation is displayed.

7. Select the component the trunnion is being added to using the icons at the top of the form:

   • Elbow

   • Tube (straight piece of pipe)

   • Eccentric reducer

   • Tee

8. Use the cursor to identify a respective branch member applicable to the icon chosen (in this case identify ELBO to create a base support).

9. At the prompt, identify the steelwork or panel you want to support from.

   The Select Trunnion Material form is displayed.

   

10. Select the piping specification of the trunnion material from a list of the available piping specifications in the current MDB.

    The default pipe specification of the parent pipe (the main branch) is highlighted by default.

    If a trunnion is added to a reducer/elbow and no connection point is found, the current pipe specification is interrogated to find the appropriate reducer/elbow and the specification reference to the new reducer is reset.

    If a trunnion is added to a tee, the tee changes to a cross and scans the current pipe specification for a suitable cross. This is required because a tee has one only connection reference.

    If a trunnion is deleted, any element reselected is replaced with the original specification reference.

11. Click OK.

    The form shown below is displayed, with Length and Trunnion Bore being active.