Page 58 - Pipeline Rules of Thumb Handbook

Construction 45

(text continued on page 42) Parts of “Bend” routine may be used for small pipe in
noncode work to determine bend angle for offsets. Do not
Formulas for scraper trap connections XEQ “Bend” for noncode work as this determines R speci-
fied by code.
Receiver. Procedure: XEQ clearing GTO “Bend.”
1
Now select a radius (try: R = 18D: 3 / 2 in. OD: R = 18 3.5/12
VR = V R - cos Trap ) sin T Trap = 5.25). This can be changed if necessary. The V distance,
- (1
+
-
=
HR H T R sin Trap + T cos Trap offset, is determined by design configuration. Store R in 08,
V in 09. Assume trial angle, say 20° for small pipe, store in
Trap 05. Let T = 0.5ft, store in 10. SF 01. XEQ 01. (Only one
LR L R
+
=
.
57 2958 calculation is performed.)
Inspect results. Do V given and V calc appear reasonably
Launcher. close? If not, take another “Fix” by changing R or angle (store
new values, XEQ 01). This routine can be continued to a
- (
1

VL = V R - cos Trap )+ T sin Trap satisfactory solution. A point will be reached where R seems
-
-
HL = H T R sin Trap + T cos Trap reasonable; choose an angle less than apparent solution, store
in 05. CF 01, store 0.5 in 11, XEQ 01 and zero in. This returns
Trap
-
LL = L R to the iterative process for a more precise solution. T and R
.
57 2958 can be changed to suit.
“Bend” routine may be used to calculate bends for cross-
Receiver trap. ing under foreign lines. (See Example 3.)
The direction change routine (XEQ 17) can be used for
VRT = VR LRT sin Trap code and noncode work. For code: determine minimum bend
-
HRT = HR LRT cos Trap radius from “Bend” for pipe size and for gas or oil line. Use
+
R from previous example or XEQ “Bend,” key in data as in
Launcher trap. Example 1 for desired diameter.
For noncode work: user may employ a radius which is suit-
+
VLT = VL LLT sin Trap able in his judgment. Do not use “Bend” program as this cal-
+
HLT = HL LLT cos Trap culates radius in accordance with codes. Key in radius and
desired tangent. Caution: be aware that short radii for large
pipes, say 8in. and larger, soon get into hot bend category.
Formulas for direction change

V = (1 cos Turn )+ T sin Turn Example 1. Offset bend
R -

T +
=
H R(sin Turn )+ (1 cos Turn ) 3
12 / 4 -in. oil line. Let V = 8ft, T = 5ft. Smaller diameters
Turn have larger bend . Try 20°, XEQ “Bend,” key in data and
+
L = 2 T R
.
57 2958 R/S. Flag 01 Clear. Use Incr. = 0.5°. Note: R/D = 18 (meets
B31.4). V Calc. is close to 8ft. Now try scraper trap routine
XEQ 15. Let trap = 5°, T = 5ft, receiver Y. Length of trap
User instructions
= 10ft. For launcher XEQ 15, same , T, receiver N. Length
of trap = 5ft.
“Bend” program. Put in calculator, Size 35, XEQ “Bend.”
Key in prompted data and R/S each time. Key in a trial angle.
Use a larger angle for smaller pipe as 15° for 12-in., 10° for
Example 2. Direction change
30-in. Results Recap prints out the calculated values and
inputs. Each quantity is identified. Additional printouts may
24-in. gas line. Note from “Bend” run Min. R = 76.3944ft.
be made by XEQ “Data.”
R/D = 38.1972, meets B31.8. Say 30° turn, let R = 80ft, T =
If one inadvertently puts in a larger trial angle than needed
5ft XEQ 17. Key in data R/S.
for a solution (i.e., calculated V approximates given V), only
one calculation is made and printed out for this angle. If
calculated V is too large, store smaller trial in 05, XEQ 01, Example 3. Crossing
to get proper result.
3
Remember to clear Flag 01 before resuming normal A 14-in. oil line crosses under 10 / 4 in. foreign line. Take
“Bend” calculations. 2ft, 0in.min. clearance. Center distance = 3.0313ft.Min.