25
TECHNICAL APPENDIX
115
TECHNICAL APPENDIX
FLOW RESISTANCE
TABLE OF FLOW RESISTANCE IN BENDS, VALVES AND GATES
The flow resistance is calculated using the equivalent pipeline length method according to the table below:
The table is valid for the Hazen Williams coefficient C = 100 (cast iron pipework). For steel pipework, multiply the
values by 1.41. For stainless steel, copper and coated cast iron pipework, multiply the values by 1.85.
When the
equivalent pipeline length
has been determined, the flow resistance is obtained from the table of
flow resistance.
The values given are guideline values which are bound to vary slightly according to the model, especially for gate
valves and non-return valves, for which it is a good idea to check the values supplied by the manufacturers.
ACCESSORY
TYPE
25
32
40
50
65
80
100
125
150
200
250
300
45
°
bend
0,2
0,2
0,4
0,4
0,6
0,6
0,9
1,1
1,5
1,9
2,4
2,8
90
°
bend
0,4
0,6
0,9
1,1
1,3
1,5
2,1
2,6
3,0
3,9
4,7
5,8
90
°
smooth bend
0,4
0,4
0,4
0,6
0,9
1,1
1,3
1,7
1,9
2,8
3,4
3,9
Union tee or cross
1,1
1,3
1,7
2,1
2,6
3,2
4,3
5,3
6,4
7,5
10,7
12,8
Gate
-
-
-
0,2
0,2
0,2
0,4
0,4
0,6
0,9
1,1
1,3
Non return valve
1,1
1,5
1,9
2,4
3,0
3,4
4,7
5,9
7,4
9,6
11,8
13,9
G-a-pcv_a_th
DN
Equivalent pipeline length (m)
TABLE OF FLOW RESISTANCE IN BENDS, VALVES AND GATES
The flow resistance is calculated using the equivalent pipeline length method according to the table below:
The table is valid for the Hazen Williams coefficient C = 100 (cast iron pipework). For steel pipework, multiply
the values by 1.41. For stainless steel, copper and coated cast iron pipework, multiply the values by 1.85.
When the
equivalent pipeline length
has been determined, the flow resistance is obtained from the table
of flow resistance.
The values given are guideline values which are bound to vary slightly according to the model, especially for
gate valves and non-return valves, for which it is a good idea to check the values supplied by the
manufacturers.
FLOW RESISTANCE
Summary of Contents for Lowara Scuba SC205C
Page 1: ...Cod 191005661 Rev A Ed 06 2017 50 Hz SCUBA Series CLOSE COUPLED SUBMERSIBLE ELECTRIC PUMPS ...
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Page 13: ...13 TECHNICAL APPENDIX ...
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