Features

1-Allow axial, lateral and angular movements
2-Accept large amounts of lateral deflection
3-Do not restrain pressure thrust
4-Adequate anchors and guides must be provided

This type of Expansion Joint is made up of two bellows joined together by a central pipe provided with welding ends.

This type of Expansion Joint is made up of two bellows joined together by a central pipe provided with flanged ends.

Universal Tied "Expansion Joints"

Description:

This model is made up of two bellows joined together by a central pipe and a system of tie rods able to withstand the thrust produced by the internal pressure.

This model is used to absorb lateral movements in all planes. In addition and with a special design and/or positioning of the tie rods system this type may be used to absorb some axial and angular movements*.

The tie rods are provided in sets of two or more, equally distributed around the circumference of the expansion joint. When the Expansion Joint is supplied with 2 tie rods at 180 degrees, the expansion joint is free to deflect angularly and laterally. With three or more tie rods only lateral deflections are possible.

The amount of lateral deflection depends on the amount of angulation each bellows can absorb and the length or the central pipe. The amount of lateral deflection capability can be increased or decreased by simply changing the length of the spool pipe and the thermal expansion of the central pipe is taken by the bellows elements.

Features:

1-Absorbs lateral movements in all planes
2-Restrains pressure thrust
3-Adequate anchors and guides must be provided

Universal Lateral Tied Expansion Joint with welding ends.

Universal Lateral Tied Expansion Joint with flanged ends.

This case illustrates how one "Universal Tied" Expansion Joint can be used to absorb the thermal Expansion in a Z-shaped section of piping which only occurs in one plane.

This case shows how an Universal Tie Expansion Jont can be used to absorb the thermal Expansion in a Z- shaped section of piping which occurs in three different directions.The fact that this type of E

Modal Frequency checking Method (Modal Analysis) using Caesar II

While performing stress analysis for process piping you might have come across the term two phase flow. The stress analysis basis or flexibility specification of most of the relevant organization informs the stress engineers to properly support these lines using hold-downs, guides and axial stops. The main reason is that two phase flow lines are vibration prone lines. Many organizations prefer to keep the natural frequency of those lines in excess of 4 Hz to reduce the possibility of vibration. Now the question is how to calculate the natural frequency of the complex piping system?
There comes the importance of a Caesar II dynamic module called Modal analysis module. The complex job of calculating the natural frequency of the piping system becomes very easy with the use of this module. The vibration response or dynamic response of any system can be easily determined using modal analysis. In actual case, Modal analysis breaks up a complex system into a number of modes of vibration, each of which is having a unique vibration response. This article will elaborate the steps followed for performing modal analysis module using Caesar II.
To start the modal analysis you must have a stress system. So from isometric model the system following conventional methods and perform the static analysis and make the system safe in all respect with respect to static analysis. Now follow the below mentioned steps for dynamic Modal analysis.

• Click on Analysis-Dynamic Analysis as shown in Fig. 1 to open the dynamic module in Caesar II. It will open the window which is shown in Fig. 2.

Fig.1: Starting Dynamic Module in Caesar II

Fig.2: Selection of Modal Analysis in Dynamic Module in Caesar II

• Now click on Analysis type and select Modal from the drop down menu. You will get the following window as shown in Fig. 3.

Fig. 3: Modal Analysis in Caesar II

• You will get four input spreadsheets as lumped masses, snubbers, control parameters and advanced.
• Click on Control parameters and it will open the window shown in Fig. 4.
• Change the frequency cut off to your desired frequency based on your project specification. If you need to arrest all frequencies below 5 Hz and set that value as 5.
• Now select the static load case for which you want to extract the natural frequencies. Normally it is advisable to select the operating temperature case.

Fig.4: Input data for Dynamic Modal Analysis