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STEAM INJECTION INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
NOTE: For Maxi-bank option, see the “Maxi-bank option piping notes” on Page
36.
1. Refer to piping drawings on Pages 31 through 35.
2. See also the “Pressurized steam piping guidelines” on Pages 10 through 13.
3. Slightly better mixing with less visible vapor travel occurs when discharged steam
blows against the airflow, rather than with the airflow. Therefore,
when using
noninsulated steam jackets in a horizontal airflow
(as shown in the drawings),
position dispersion tubelets (steam orifices) so that they face into the airflow. If the
dispersion tube has an insulated jacket, the discharged steam must blow with the
airflow to avoid condensation that may occur when discharged steam contacts
the cooler insulated jacket. Therefore,
when using insulated steam jackets in a
horizontal airflow
, position dispersion tubelets so that they discharge steam with
the airflow, and also add 24" (610 mm) to the non-wetting absorption distance.
4. Jacket piping size:
• 1/2" pipe thread (DN15) for Model 60 tubes
• 3/4" pipe thread (DN20) for Model 70 tubes
• 1½" pipe thread (DN40) for Model 80 tubes
5. To ensure uniform output from each tube, connect steam supply as close to the
middle of the header as possible, but not in direct alignment with a dispersion
tube.
6. See header sizing in Table 28-1.
7. After the unit is installed, secure steam jacket piping to the tube header.
8. If steam pressure is less than or equal to 15 psi (103.4 kPa), use float and
thermostatic (F&T) traps for the humidifier. If steam pressure is greater than 15
psi (103.4 kPa), use inverted bucket traps for the humidifier. If lifting condensate,
use an inverted bucket trap and check valve regardless of steam pressure
(Figure 12-1).
9. Due to the pressure drop across the valve, the steam pressure at the header
trap is minimal; therefore, you cannot lift condensate or return condensate to a
pressurized return by steam pressure from this trap. However, with condensate
free steam, no trap is required if load is less than 500 pph, and between 500
and 1000 pph a trap is optional. Above 1000 pph, a trap is recommended.
10. X = distance between tubes, center to center
Y = clearance at top and bottom = at least 1/2 of X or 4½" (114 mm),
whichever is greater, but not greater than X
See the minimum tube spacing in Table 29-1.
11. When installing in a vertical airflow:
Always point tubelets (steam orifices) up when installing in a vertical airflow.
I m p o r t a n t :
If installing insulated steam jackets in a vertical airflow, install only
in an upflow application and add 24" (610 mm) to the non-wetting absorption
distance.
Do not install insulated steam jackets in a vertical downflow application .
Piping notes
MULTIPLE-TUBE HUMIDIFIER
For total dispersion tube lengths of more
than 45’ (13.7 m), see Step 10 note on
