Design Options - Tubesheet
Figure Design options tubesheet
The tab tubesheet in the design options window provides the setting for the tubesheet detail dimensions and the U-tube distances to the rear head of the heat exchanger. The following picture illustrates the front or rear end tube extension.
Figure tube extension
The extensions are usually required for tube expansion in the tube sheet or welding purposes. The tube extension can be also zero in case of a vertical heat exchanger where the fluid has to flow from the top tubesheet in to the tubes.
The tubes in a U-tube configuration have clearances at the end head or bonnet which can be set by the user. These values are for drawing and positioning of the components only and have no influence on the calculations.
Figure U-tube clearances
- The clearance of U-bends to bonnet is illustrated with number 1 in figure 'U-tube clearances'
- The clearance between the support plate to the U-bend is indicated with number 2
- The extra tube length per U-bend is to ensure that enough clearance remains between the various U-tubes with different radii. A common distance is 6 mm increase per larger U-tube bend radius.
The tube sheet extensions reduction is indicated with number 5 in figure 'spacing and confining dimension tubesheet and flange'
figure Distance OTL to Confining diameter
The Outer Tube Limit (OTL) to confining diameter in a floating tubesheet is indicated with difference between number 1 and 2. figure Distance OTL to Confining diameter