Isolation Dampers
Introduction
A range of high integrity dampers has been designed
also available. These units are designed to be fully
to meet the requirements of the oil and gas, nuclear
open or fully closed. If intermediate blade positions
& process industries, where corrosion resistance
are required a modulating control damper should be
and mechanical integrity are of prime importance.
incorporated in the system.
The following design features have been included:
Control Options
Continuously welded construction
Opposed blade motion
Refer to details in the Controls section (page 12)
Low casing leakage
Low blade leakage
Options
Low airflow resistance
Low noise generation
The following options can be incorporated if required.
Manual, pneumatic, or electric operation
Oil impregnated bronze sintered bearings in place of
Wide range of materials
acetal. Reduced cost riveted/welded/sealed con-
Excellent corrosion resistance
struction. Heavy duty 1.5 mm double skin blades
welded to continuous solid shafts.
Description
Modifications to meet specific client specifications, eg
BNF Plc NF specifications.
Casing
Leakage Rates
This is a continuously welded channel section con-
The Isolation damper has been designed to minimise
struction and is available in a range of materials and
leakage with the blades in the closed position. To put
thickness. Typically: Stainless steel (1.5 mm to
a precise figure on the leakage rate is not practical
3.0 mm thick) grade 316L or 304, mild steel, gal-
due to variations in configuration, aspect ratio, num-
vanised after manufacture (3.0 mm or 5.0 mm thick).
ber of blades and perimeter length of dampers with
Angles with closed cell gaskets are fitted at the top
equivalent face areas. Extensive testing on single
and bottom as well as stainless steel (type 316)
module dampers of size 1000 mm wide x 1000 mm
sprung side seals in order to achieve an effective seal
high, has indicated a mean leakage rate of 0.081
between the damper case and the blades.
m3/sec/m2 at a differential pressure of 2000 Pa.
Modifications to meet specific client specifications, eg
Blades
BNF Plc NF specifications. Specifications should be
discussed with our engineers.
These are of stainless steel grade 316L or 304
throughout. They are of double skin aerofoil section.
Blades are riveted to continuous tubu-
lar spindles. The spindles rotate in
acetal resin bushes and are linked
externally to provide opposed blade
motion.
Control Mechanism
Manual Isolating Damper: This is oper-
ated by a robust adjusting handle with
a locking device which moves across a
quadrant plate. Moving the handle
through 90° moves the blades from
the fully open to the fully closed posi-
tion, thereby enabling the unit to be
used for volume control purposes if
necessar y.
Pneumatic and Electric Isolating
Dampers: These are operated by actu-
ators which move the blades from fully
open to fully closed.
The actuator is controlled by either a
pneumatic or electric signal. Micro-
switches, indicating blade position, are