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Page 28
2008-10-01
2. STEAM ABSORPTION AND DISTRIBUTION
A.
VARIABLES THAT AFFECT ABSORPTION DISTANCES
(1) This manual will help in the design of a steam distribution system to provide the
optimum performance from the humidifier and absorption of steam within the duct
system.
(2) Experience has shown that absorption of steam is affected primarily by the
psychrometric conditions of the air based on how much residual capacity at a given air
volume and temperature exist to hold the moisture being introduced.
(3) To properly introduce steam into an air stream, five variables must be known:
(a) Temperature (°F or °C). If the air temperature varies, pick the lowest temperature.
(b) Highest humidity level before the distributor (%rh).
(c) The amount of moisture being added resulting in a change of rh in the duct or
plenum (
Δ
%rh).
(d) Minimum velocity of the air (FPM).
(e) The size of the duct or plenum (cross section area).
(4) As a guide, Table 8 shows how each variable affects the absorption distance.
(5) Table 9 shows examples of typical absorption distances in air handling systems.
(6) Referring to Figure 3, ‘D’ can vary between 1 to 20 feet depending on the airflow’s:
(a) Velocity (V)
(b) Temperature (T)
(c) Humidity (H)
(7) When (V) is 500 fpm, (T) is high (90 to 130°F) and (H) is low (10% to 30% rh) the ‘D’ will
be 1 to 2 feet. As the (H) goes up ‘D’ becomes longer. Similarly, as (T) goes down, ‘D’
goes up. High velocity also increases ‘D’ by moving the steam further down stream
before it can mix. Multiple distributors will shorten the steam absorption distance.
Table 8. Variables That Affect Absorption Distances
Variables
Effect On Absorption Distance
(NOTE:
↑
Increase
↓
Decrease
Air Temperature
↑
↓
Air Temperature
↓
↑
Air Humidity
↑
↑
Air Humidity
↓
↓
Large Increase of RH
↑
Small Increase of RH
↓
High Air Velocity (1000 fpm or above)
↑
Low air Velocity (between 100 and 500 fpm)
↓
Small Duct or Plenum (short distributor)
↑
Large Duct or Plenum (long distributor)
↓
Содержание NHPC
Страница 1: ...2538144 B NH Series NHTC NHPC ELECTRODE STEAM HUMIDIFIER Engineering Manual TM ...
Страница 9: ...10 00 Page 1 2008 10 01 10 00 INTRODUCTION ...
Страница 10: ...10 00 Page 2 2008 10 01 Figure 1 NHTC ...
Страница 13: ...10 00 Page 5 2008 10 01 Figure 2 Optimum Boiling Time Figure 3 Conductivity ...
Страница 18: ...10 00 Page 10 2008 10 01 Figure 6 Typical NHRS Installation Sheet 1 of 2 ...
Страница 19: ...10 00 Page 11 2008 10 01 Figure 7 Typical NHRS Installation Sheet 2 of 2 ...
Страница 20: ...10 10 Page 12 2008 10 01 10 10 HUMIDITY STEAM ABSORPTION AND DISTRIBUTION ...
Страница 35: ...10 10 Page 27 2008 10 01 Figure 2 Psychrometric Chart ...
Страница 47: ...10 10 Page 39 2008 10 01 Figure 13 Humidification Distance Nomogram Figure 12 Cutting Duct For Mounting ...
Страница 58: ...10 10 Page 50 2008 10 01 Figure 26 Typical SAM e Installation for Atmospheric Steam Applications ...
Страница 64: ...10 10 Page 56 2008 10 01 Figure 30 NORTEC OnLine Monitoring ...
Страница 71: ...10 20 Page 63 2008 10 01 10 20 SPECIFICATIONS ...
Страница 81: ...10 30 Page 73 2008 10 01 10 30 SUBMITTALS ...
Страница 86: ...10 30 Page 78 2008 10 01 Figure 2 Primary Line Voltage Wiring to Unit ...
Страница 87: ...10 30 Page 79 2008 10 01 Figure 3 Physical Data NHTC NHPC 005 030 ...
Страница 88: ...10 30 Page 80 2008 10 01 Figure 4 Physical Data NHTC NHPC 050 100 ...
Страница 89: ...10 30 Page 81 2008 10 01 Figure 5 Physical Data NHTC NHPC 150 200 ...
Страница 95: ...10 30 Page 87 2008 10 01 Figure 11 In Duct AHU Installation Without Mounting Frame Installation ...
Страница 96: ...10 30 Page 88 2008 10 01 Figure 12 In Duct AHU Installation With Mounting Frame Installation ...
Страница 97: ...10 30 Page 89 2008 10 01 Figure 13 Outside Duct Installation Without Mounting Frame Installation ...
Страница 98: ...10 30 Page 90 2008 10 01 Figure 13 In Duct AHU Installation With Mounting Frame Installation ...
Страница 99: ...10 30 Page 91 2008 10 01 Figure 14 Vertical Duct Installation Figure 15 Outside Duct Mounting Cover Plates ...
Страница 100: ...10 30 Page 92 2008 10 01 Figure 16 Atmospheric SAM e Adapter Dimensions ...
Страница 101: ...10 30 Page 93 2008 10 01 Figure 17 Atmospheric Steam Header and Adapter Configuration ...
Страница 102: ...10 30 Page 94 2008 10 01 Figure 18 Physical Data for Remote Mounted Blower Pack ...
Страница 103: ...10 30 Page 95 2008 10 01 Figure 19 Physical Data Units with Optional Built On Blower Packs ...
Страница 104: ...10 30 Page 96 2008 10 01 Figure 20 Physical Data Units with Optional Built On Blower Packs ...