Untitled Document

For convenience of application we have developed several standard designs of the type H exchanger and have assembled the details in this catalog.

Heat Exchangers:
D & R Model "LL" for fluid to fluid service
D & R Model "LLS" for steam to fluid sevice with the steam condensing on the shell side
D & R Model "LST" for steam to fluid service with the steam condensing on the tube side

Model numbers of D & R exchangers can be determined easily by assembling a few pertinent factors. The result will generally describe the unit and simplify identification.

Example:
D & R Model LLS 105U4-8H reading from left to right describes a fluid heater with a steam on the shell side and fluid on the tube side. The unit consists of a 10-3/4" shell, 5/8" O.D. U-tubes, 4 pass tube side with a nominal tube bundle length of 8'0" for horizontal installation.

This is determined as follows:

1

2

3

4

5

6

LLS

10

5U

4

8

H

1. Model "LLS" (from general catagories outlined above)
2. Nominal shell size (10-3/4" O.D.) -- 10
3. U-tube diameter in eighths of an inch -- 5U equals 5/8" O.D. U-tube
4. Tube side pass arrangement -- 4
5. Nominal bundle lenght in feet -- 8
6. Horizontal installation -- H

Example Problem:
Select a horizontal liquid to liquid heat exchanger with approximately 200 sq. ft. surface. Nickel tube side with 3/4" O.D. x 16 BWG tubes, four tube side passes with a maximum overall length of 18'0".

Our general selection in this instance will be a Model "LL" for the liquid to liquid service specified. The tube pass arrangement has been predetermined (4) as well as the tube size 3/4" O.D. x 16 BWG, tube designation Group 6. From the table of the Dimensional Standards and Surface Areas we find that Model "LL" exchangers, four tube passes are detailed on the following pages, including Dimensional data for four pass tube side arrangements, triangular tube pitch, Group 6 tube size in the column entitled D & R Standard Model "LL" for Group 6 (the predetermined tube size), find that under Nominal Bundle length of 16'0" (the specification calls for 18'0" maximum overall length) the listed surface area nearest the 200 sq. ft. surface specified has a 10-3/4" shell and provides 209 sq. ft., a satisfactory selection.

You now have sufficient information for a complete model designation:

Model

"LL"

Nom. shell size

10

U-tube size

6U

Pass Arrangement (tube side)

4

Tube length, 10'0"

16

Horizontal installation

H

The figures above (in bold type) form a complete D & R Model Designation.