Cumberland VariFlame VF-16-ONG, Руководство пользователя

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Chapter 4: Installation
Pipe Section
No. Of
Heaters
HVR Calculation HVR Value
BTUH kW BTUH kW
b-f 1
1 x 40,000
1 x 12
40,000
12
c-g
1
1 x 40,000
1 x 12
40,000
12
• Determine the ELOP. Length from meter to most remote heater = length from a to e (or g) = 100ft
(30m) + 25ft (8 m) = 125ft (38 m) Minor loss equivalents from Table 1 = 1 gate valve x 2ft/valve (1 m/
valve) + 3 tees x 11 ft/tee (4 m/tee) =35ft (13 m). Calculated ELOP = 125ft (38 m) + 35ft (13 m) =
160 ft (51 m) Tabulated ELOP = 200ft (60 m) Round up to the nearest table value.
• In the appropriate table, NG (Table 2) or LP (Table 3), select the column showing the ELOP or the
next longer length, if the table does not give the exact length. Use this column to compare table
values to the HVR values. Use the Natural Gas table (Table 2) in this example. From step 2, ELOP =
200ft (60 m) Locate the column labeled 200ft (60 m) in Table 2.
• Select a pipe section and read down the ELOP column to find the maximum gas capacity that
matches the HVR for that particular pipe section. If the exact value is not listed, choose the next
larger value in the column. In this example, start with pipe section c-e. For pipe section c-e, HVR =
40,000 BTUH (12 kW). From Table 2, column 200 ft, 40 (12) is not listed (NOTE: The table values
are in thousands of BTUH's). The next larger value of 72 (21) is read from the table, corresponding
to 72,000 BTUH (21 kW).
• Follow the row leftward until you reach the columns labeled 'Internal Diameter' and 'Nominal pipe
size'. Read the pipe size for the particular pipe section. For example, for pipe section c-e, the pipe
size is ¾ inch (0.824 in.) (19.1 mm). Repeat for each pipe section.
Table 4-1 Minor Loss Equivalents
Fitting
2 in. (5.08 cm) IPS or Smaller
2 to 4 in. (5.08 to 10.16 cm) IPS Meters
per fitting
Feet per Fitting Meters per fitting Feet per Fitting Meters per fitting
45° Elbow 3 1 5 2
90° Elbow 6 2 10 3
Tee 11 4 20 6
Gate Valve 2 1 3 1
Angle Valve 29 9 60 18
Swing Valve 15
5
30 9
Table 4-2 Pipe Sizes Determined for Diagram
Pipe Section Max Gas Capacity Value Determined
From Table 2
Pipe Size Determined From Table 2
BTUH kWh inches
mm
a-b 280,000 82 1-1/4 in. 31.8
b-c 135,000 40 1 in. 25.4
b-d 72,000 21 ¾ in 19.1
b-f 72,000 21 ¾ in. 19.1
c-e
72,000 21 ¾ in. 19.1
c-g
72,000 21 ¾ in. 19.1
PNEG-2091 VariFlame™ Heater 33