Advertisement
How to Find Valve Pressure Drop
The pressure drop in psi (kPa), equivalent ft (m) of pipe, or feet
of water (kPa) may be calculated from Figs. 3 through 8 as
follows:
1. Calculate the flow rate to heat the zone.
2. Determine the Cv (kV) rating of the motorized valve.
3. Select the graph corresponding to the Cv (kV) rating
(Fig. 3 through 8).
4. Determine the pressure drop across the valve using the
following procedures for calculating pressure drop.
PRESSURE DROP IN PSI (KPA)
1. Locate the flow rate at the bottom of the graph.
2. Draw a line upward from the flow rate to the intersection
of the curve.
3. Draw a line from the intersection to the left edge of the
graph to determine the pressure drop in psi (kPa).
PRESSURE DROP IN EQUIVALENT FT (M) OF PIPE
NOTE: Both 1/2 and 3/4 in. pipe conversion scales are avail-
able for this determination.
1. Locate the flow rate at the bottom of the graph.
2. Draw a line vertically to the top of the graph. Determine
the pressure drop for either the 1/2 or 3/4 in. pipe.
PRESSURE DROP IN FT OF WATER (KPA)
1. Locate the flow rate at the bottom of the graph.
2. Draw a line upward from the flow rate to the intersection
of the curve.
3. Draw a line from the intersection to the right edge of the
graph to determine pressure drop in ft of water (kPa).
PRESSURE DROP, EQUIVALENT FEET OF PIPE (EQUIVALENT METERS OF PIPE)
90
100
120
140
(27)
(30)
(37)
(43)
(1/2 IN. PIPE)
30 (207)
20 (138)
10 (69)
9 (62)
8 (55)
7 (48)
6 (41)
5 (34)
4 (28)
3 (21)
2 (14)
1 (7)
0
6
2
4
(0.13)
(0.25)
(0.38)
GAL/MIN (l/s) FLOW RATE
Fig. 3. Flow characteristics of 1 Cv (0.86 kv) flow.
V4043A,B,E,J; V4044A,B; V8043A,B,E,F,J; V8044A,B,E MOTORIZED VALVES
750
500
600
700
(213)
(229 )
(152)
(183)
(3/4 IN. PIPE)
-50 (149)
-40 (119)
-30 (89.5)
-20 (60)
-10 (30)
1CV
(0.86 KV)
-5 (15)
8
10
12
(0.5)
(0.63)
(0.76)
PRESSURE DROP, EQUIVALENT FEET OF PIPE (EQUIVALENT METERS OF PIPE)
45
(13.7)
(3/4 IN. PIPE)
8
9
10
(2.4)
(2.7)
(3)
50.0 (345)
10.0 (69)
5.0 (34)
1.0 (7)
.50 (3.4)
.10 (0.69)
.05 (0.34)
0
2
(0.13)
Fig. 4. Flow characteristics of V4043A model with 2.5 Cv
(2.1 kv) rating and V4044A and V8044A bypass port (B)
with 2.5 Cv (2.1 kv) (reduced) rating.
PRESSURE DROP, EQUIVALENT FEET OF PIPE (EQUIVALENT METERS OF PIPE)
(3/4 IN. PIPE)
9.0
(2.7) 10
8.0
(2.4)
(3)
50.0 (345)
10.0 (69)
5.0 (34)
1.0 (7)
0.50 (3.4)
0.10 (0.69)
0.05 (0.34)
0
0
2
(0.13)
M9183A
Fig. 5. Flow Characteristics of 3.5 Cv (3.0 kv) valve.
7
60
65
70
(18)
(20)
(21.3)
11
12
12.5
13
(3.4)
(3.6)
(3.8)
(4)
(1/2 IN. PIPE)
2.5CV
(2.1 KV)
4
6
8
10
12
(0.25)
(0.38)
(0.5)
(0.63)
(0.76)
GAL/MIN (l/s) FLOW RATE
45
60
65
70
(13.7)
(18)
(20)
(21.3)
11
12
12.5
13
(1/2 IN. PIPE)
(3.4)
(3.6)
(3.8)
(4)
3.5CV
(3.0 KV)
4
8
10
6
(0.5)
(0.63)
(0.76)
(0.25)
(0.38)
GAL/MIN (l/s) FLOW RATE
80
(24.4)
-50 (149)
-40 (119)
-30 (89.5)
-20 (60)
-10 (30)
-5 (15)
-1 (3)
-0.5 (1.5)
-0.1 (0.3)
-0.05 (0.15)
14
(0.88)
M9184A
80
(24.4)
-50 (149)
-40 (119)
-30 (89.5)
-20 (60)
-10 (30)
-5 (15)
-1 (3)
-0.5 (1.5)
-0.1 (0.3)
-0.05 (0.15)
12
14
(0.88)
M5979B
60-2133—10
Hide quick links:
Advertisement
