Tube Selection Example
P
To select tube material and tube sizes for pressure, return
and suction lines for a hydraulic power unit with the following
operating parameters known:
Type of fluid: Petroleum base hydraulic fluid
Operating temperature range: -20°F to +140°F.
Maximum operating pressure: 3500 psi
Maximum flow rate through each line: 10 GPM
Severity of service: A (normal)
1.
Selecting Tube Material:
Table T6
indicates that carbon
steel, C-1010, tubing would meet the media, operating
temperature range, and maximum operating pressure
(
high) requirements.
2.
Sizing the Tube:
From
Table T1,
the recommended flow
diametersforvariouslinesfor10GPMflowrateare:0.405for
pressure line, 0.639 for return line, and1.012 for suction line.
Now, using
Tables T20
and
T21,
we need to find tubes with
inside diameters (I.D.) equal to or larger than the above
flow diameters, and wall thicknesses appropriate for
design pressures of 3500 psi minimum for the pressure
line and about 500 psi for return and suction lines. Since
derating factors for Severityof Servic
e (TableT19)
andMax.
Operating Temperature
(Table T7)
are both 1, design
pressure values in
Tables T20
and
T21
do not need to be
reduced. Matching tube I.D.s and design pressures in
Tables T15 a
n
d T16 f
or above conditions, we find:
For the pressure line, we would choose 5/8" O.D. x .083"
wall tubing. The .095" and .109" wall tubes would also
be satisfactory if .083" wall is not readily available.
For the return line, either 3/4" x .035" or 3/4" x
.049"
would meet the requirements. If Ferulok
fittings are being used, we will need to go
to 3/4" x .065" because .065" is the smallest
wall thickness recommended for 3/4" O.D. tubing used
with Ferulok fittings in Table T22. This reduces the flow
diameter about 3% below the recommended value, but
is still in the acceptable range. The alternative is to go
to 7/8" O.D. x .072" wall tubing, which is way too large.
For the suction line, we can use any one of the
following tubes: 1-1/4” O.D. x .049” to .083” wall tube
for Triple-Lok or Seal-Lok fittings and 1-1/4” O.D. x
.095”
wall tube for Ferulok fittings.
One final consideration in choosing the right
wall thickness for tubing is bending. If bending
without the use of a mandrel is desired, then wall
thicknessof less than7%of tubeO.D. shouldnotbeused.
T28
Parker Hannifin Corporation
Tube Fittings Division
Columbus, Ohio
http://www.parker.com/tfd
4300
Catalog
General Technical
Dimensions and pressures for reference only, subject to change.
C)
A)
B)
1)
Brazing to attach sleeve can be used for all wall
thicknesses. For flanging tool availability, see
page R24.
Table T22 — Recommended “Min./Max” Tube Wall
Thickness for Common Fittings
Tube Material
Steel
St. Steel
Copper
Aluminum
Steel
St. Steel
Monel
Steel
Alloy Steel
St. Steel
Copper
Monel
Copper
Aluminum
Plastics
Steel
St. Steel
Size
O.D.
(
in.)
O.D.
(
mm)
Dash
#
SAE
37
° Flare
Triple-Lok
SAE
Flareless
Ferulok
SAE O-Ring
Face Seal
Seal-Lok
Intru-Lok
Metric
Flareless
1/8 4 -2 .010 - .035 .010 - .035 — .012 - .028 0.5 - 1
3/16 6 -3 .010 - .035 .020 - .049 — .012 - .035 1 - 2
1/4 8 -4 .020 - .065 .028 - .065 .020 - .083 .020 - .049 1 - 2.5
5/16 10 -5 .020 - .065 .028 - .065 .020 - .095 .020 - .065 1 - 3
3/8 12 -6 .020 - .065 .035 - .095 .020 - .109 .028 - .065 1.5 - 3.5
1/2 14 -8 .028 - .083 .049 - .120 .028 - .148 .035 - .083 1.5 - 4
5/8 15 -10 .035 - .095 .058 - .120 .035 - .134 .035 - .083 1.5 - 4
3/4 16 -12 .035 - .109 .065 - .120 .035 - .148 .035 - .095 2 - 4
7/8 18 -14 .035 - .109 .072 - .120 — .049 - .095 2 - 4
1 20 -16 .035 - .120 .083 - .148 .035 - .188 .049 - .120 2.5 - 4
1 1/4 22 -20 .049 - .120 .095 - .188 .049 - .220
2.5 - 4
1 1/2 25 -24 .049 - .120 .095 - .220 .049 - .250
2.5 - 4.5
2 28 -32 .058 - .134 .095 - .220 .065 - .220
2.5 - 4.5
30
2.5 - 5
35
3 - 5
38
3 - 6
42
3.5 - 7
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