Información Técnica

Agency Specifications and Hose Selection Guide

Industry Agencies

SAE - Society of Automotive Engineers

DNV - Det Norske Veritas for North Sea

RCCC - Regular Common Carrier Conference

DIN - Deutsch Industry Norm, German

BCS-174 - Natonal Coal Board, British

IJS - Industrial Jack Specifications

Presure Conversions

Metric to PSI (1kPa = .145psi)

Kilo Pascals (kPa)
Mega Pascals (MPa)
Bar (Bar)
Pounds per Square Inch (psi)
100
0.1
1
14.5
200
0.2
2
29.0
300
0.3
3
43.5
400
0.4
4
58.0
500
0.5
5
72.5
600
0.6
6
87.0
700
0.7
7
101.5
800
0.8
8
116.0
900
0.9
9
130.5
1000
1.0
10
145.0
2000
2.0
20
290.1
3000
3.0
30
435.1
4000
4.0
40
580.2
5000
5.0
50
725.2
6000
6.0
60
870.2
7000
7.0
70
1015.3
8000
8.0
80
1160.3
9000
9.0
90
1305.3
10000
10
100
1450
20000
20
200
2901
30000
30
300
4351
40000
40
400
5802
50000
50
500
7252
60000
60
600
8702
70000
70
700
10153
80000
80
800
11603
90000
90
900
13053
100000
100
1000
14504
200000
200
2000
29008
300000
300
3000
43511

PSI to Metric (1 psi = 6.89 kPa)

Pounds per Square Inch (psi)
Kilo Pascals (kPa)
Mega Pascals (MPa)
Bar (Bar)
10
68.9
0.07
0.7
20
137.9
0.14
1.4
30
206.8
0.21
2.1
40
275.8
0.28
2.8
50
344.7
0.34
3.4
60
413.7
0.41
4.1
70
482.6
0.48
4.8
80
551.6
0.55
5.5
90
620.5
0.62
6.2
100
689
0.7
6.9
200
1379
1.4
13.8
300
2068
2.1
20.7
400
2758
2.8
27.6
500
3447
3.4
34.5
600
4137
4.1
41.4
700
4826
4.8
48.3
800
5516
5.5
55.2
900
6205
6.2
62.1
1000
6895
6.9
68.9
2000
13790
13.8
137.9
3000
20684
20.7
206.8
4000
27579
27.6
275.8
5000
34474
34.5
344.7
6000
41369
41.4
413.7
7000
48263
48.3
482.6
8000
55158
55.2
551.6
9000
62053
62.1
620.5
10000
68948
68.9
689
20000
137895
137.9
1379
30000
206843
206.8
2068
40000
275790
275.8
2758

 

Hydraulic System

What is Pressure Drop?

As related to our business, pressure drop is the difference between the pressure of a fluid as it enters one end of hydraulic hose assembly and the pressure of that fluid as it leaves the other end. There will be a difference in pressure, and it will be less. How much less depends on what is between the beginning and end of the hose assembly. Here are some examples of things that can influence the amount of pressure drop.

1.- FRICTION-- This is the rubbing of fluid against the inside walls of the hose assembly.

2.- TYPE OF FLUID-- Different fluids behave differently under pressure. Thicker fluids are moved with greater difficulty and will exhibit greater pressure drop-

3.- TEMPERATURE OF THE FLUID-- Warming fluids thins them so they are moved more easily, as wih automotive oil.

4.- LENGTH OF HOSE ASSEMBLY-- The longer it is, the more surface there is for friction to decrease pressure.

5.- SIZE (I.D) OF HOSE-- Affects the fluid velocity for a given flow rate. Higher velocities result in greater pressure drop. Therefore, a larger I.D. hose will produce less pressure drop-

6.- TYPE OF COUPLINGS & ADAPTERS-- Any change in bore or change in direction (such as with 45º or 90º elbows) can increase the amount of pressure drop.

7.- FLOW RATE-- Pressure drop increases with flow rate for same size hose.

Who Cares About Pessure Drop?

Suppose you need 4,000 psi of output from a hose assembly for hydraulic equipment to run efficiently. There will be some pressure drop and you must allow for it in helping to plumb the system with Gates hose, couplings and adapters. This means that the input pressure to the hose assembly must be equal to the output plus the amount of pressure drop- If the pressure drop in this example is 150 psi, then you will need 4,150 psi of input.

How Can You Determine The Amount Of Pressure Drop?

That`s the easy part of it. Contact your local Gates representative who is traind and equipped to quickly solve such problems for you.

He will need input variables and fittings used from you as shown (see below). A Gates Pressure Drop analysis printed below will then be provided for your applicaton.

Sample Pressure Drop Analysis

Input Variables:

Flow Rare: 15 (GPM)

Viscosity: 20.0 (Centistokes)

Specific Gravity: 0.85

Free Hose Length: 20.0 (ft)

Fittings Used:

1. Standard Straight Fitting

2. 90-degree Angle Coupling

 

Dash Size (1/16©)
Velocity (Ft/Sec)
Hose Pressure Drop (psi/Ft)
Total Presure Drop-Hose & Fittings (psi)
(1) Reynolds Number
(2) Heat Gain (BTUH)
(3) Horsepower Loss
5
62.8
28.8
789.6
7584
17483
6.87
6
43.6
12.2
399.1
6320
8838
3.47
8
24.5
3.2
81.3
4740
1801
0.71
*10
15.7
1.1
31.2
3792
691
0.27
12
10.9
0.5
12.7
3160
280
0.11
16
6.1
0.1
2.6
2730
58
0.02
20
3.9
0.0
0.8
1896
18
0.01
*Recommended hose size, based on velocity, pressure drop, heat gain and hp loss

 

(1) Reynolds Number =
inertia flow forces
indicates the type of flow
 
Friction forces (or viscosity)
 
 
 
 
Reynolds No. Range
Type of Flow
 
0-2000
laminar
 
2000-3000
transient
 
3000 +
turbulent

(2) Heat Gain is the total amount of energy converted to heat energy which will raise the fluid temperature if it is not dissipated.
(3) Horsepower Loss I a measure of the conversion of mechanical energy to heat energy and is related to system heat gain.

---------------------------------------------------------------------------------------------------------------------------------

 

Decimal and Milimeter Equivalents of Fractions

Inches
Millimeters
Fractions
Decimals
1/64"
.015625
0.3969
1/32"
.03125
0.7937
3/64"
.046875
1.1906
1/16"
.0625
1.5875
5/64"
.078125
1.9844
3/32"
.09375
2.3812
7/64"
.109375
2.7781
1/8"
.125
3.1750
9/64"
.140625
3.5719
5/32"
.15625
3.9687
11/64"
.171875
4.3656
3/16"
.1875
4.7625
13/64"
.203125
5.1594
7/32"
.21875
5.5562
15/64"
.234375
5.9531
1/4"
.25
6.3500
17/64"
.265625
6.7469
9/32"
.28125
7.1437
19/64"
.296875
7.5406
5/16"
.3125
7.9375
21/64"
.328125
8.3344
11/32"
.34375
8.7312
23/64"
.359375
9.1281
3/8"
.375
9.5250
25/64"
.390625
9.9219
13/32"
.40625
10.3187
27/64"
.421875
10.7156
7/16"
.4375
11.1125
29/64"
.453125
11.5094
15/32"
.46875
11.9062
31/64"
.484375
12.3031
1/2"
.5
12.7000
33/64"
.515625
13.0969
17/32"
.53125
13.4937
35/64"
.546875
13.8906
9/16"
.5625
14.2875
37/64"
.578125
14.6844
19/32"
.59375
15.0812
39/64"
.609375
15.4781
5/8"
.625
15.8750
41/64"
.640625
16.2719
21/32"
.65625
16.6687
43/64"
.671875
17.0656
11/16"
.6875
17.4625
45/64"
.703125
17.8594
23/32"
.71875
18.2562
47/64"
.734375
18.6531
3/4"
.75
19.0500
49/64"
.765625
19.4469
25/32"
.78125
19.8437
51/64"
.796875
20.2406
13/16"
.8125
20.6375
53/64"
.828125
21.0344
27/32"
.84375
21.4312
55/64"
.859375
21.8281
7/8"
.875
22.2250
57/64"
.890625
55.6219
29/32"
.90625
23.0187
59/64"
.921875
23.4156
15/16"
.9375
23.8125
61/64"
.953125
24.2094
31/32"
.96875
24.6062
63/64"
.984375
25.0031
1"
1.
25.4001