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Dampers

Flowseal Engineering (Pty) Ltd are specialists in the design and manufacture of isolation and control dampers.

The following are an example of our extensive product range and field of expertise:

Butterfly Dampers

These can be manufactured circular or rectangular, in a variety of configurations to suit a multitude of applications.

Sealing arrangements range from “swing through” for control only to stainless steel flexible blade seals for isolation efficiencies greater than 99% sealing efficiency.

Although mainly used for isolation, they can be used for control.

Dampers can be manufactured in a variety of materials and can be supplied with refractory lining if required.Applications range from simple isolation dampers at ambient temperatures with manual lever arm operation to control dampers at temperatures as high as 2000°C (water cooled casing and blade).

Guillotine Dampers

Guillotine Dampers are generally used where high efficiency isolation is required, or in cases where it is inadvisable to have any blades in the gas stream, due to abrasion – they are not suitable as control dampers.

Various sealing arrangements are available, including purge air arrangements to provide total isolation of process gas.

These dampers are of extremely robust construction, with all components requiring maintenance placed on the outside, permitting maintenance to take place whilst the plant is on line.

The preferred blade drive mechanism is by heavy duty chains and sprockets, which have proved to be totally reliable-even in instances when the dampers are only operated once per year during maintenance shut downs.

Materials of construction, refractory lining, if required, and drive configurations are selected and designed to suit the application and customer requirements.

Diverter, Dilution And Swing Dampers

The variations possible for these dampers are virtually infinite.

All types can be manufactured as either “open / close” or as control dampers, and in the case of diverter dampers, the blades may be linked and operated by a single actuator or they may be operated individually.

Dilution dampers could be of the flap type round or rectangular, and with resilient seats or rectangular louver construction with special seal arrangement to reduce indraught air leakage.

Swing dampers provide a means of keeping the blade out of the gas stream when in the open position and are particularly suitable for cases where the gas stream contains abrasive particulate.

Materials of construction and drive configurations are selected and designed to suit the application and customer requirements.

Louver Dampers

Louver Dampers can be manufactured circular or rectangular, and in a variety of configurations.

Generally, multi-blade louver dampers are used as control dampers – or as isolation dampers in rectangular or square ducts of a large cross sectional area, where use of a single blade would be impractical.

Due to the multiple blade arrangement, sealing efficiencies are lower than in single blade butterfly dampers.

However, by placing two louver dampers adjacent to each other and purging the cavity between the two sets of blades when closed, with air at a higher pressure than the system pressure, total isolation of process gas may be achieved.

When used as control dampers, the blades are normally arranged to counter rotate, this provides very good control characteristics through the entire range of operation.

Materials of construction, gland seal and bearing arrangements and drive configurations are selected and designed to suit the application and customer requirements.

Radial Vane Control Dampers

These are primarily intended as fan inlet control dampers where, by introducing swirl into the inlet of the fan in the direction of rotation, the fan curve is changed as the damper moves, thus maintaining operation at an efficient point on the fan curve and eliminating the possibility of stalling at low volumes.

The dampers can be designed to suit overhung impellers or impellers with through shafts and can be built for double inlet fans and operated by a single drive mechanism.

Materials of construction and drive configurations are selected and designed to suit the application and customer requirements

Knife Gate Dampers

Knife gate dampers perform the same functions as a guillotine damper, which is to provide a damper where the blade is removed from the air steam whilst in the open position, but are generally smaller in size.

Knife gate dampers can be manufactured with an enclosed bonnet into which the blade is retracted when open. Drive arrangements are of the screw jack type with either a rising or non-rising spindle.

Knife gate operators very from hand or chain wheel to electric motor driven and linear pneumatic.

Knife gate dampers are particularly suited to higher pressure applications where high sealing efficiencies are required such as pulverised fuel feed lines or as isolation valves on sulphuric acid plants.

Materials of construction and drive configurations are selected and designed to suit the application and customer requirements

Flowseal Knife Gate Dampers are designed and fabricated to meet the requirements of power and industrial plants and comply fully with the requirements of AMCA publication 850-84. They provide effective and reliable isolation in hot, noxious, corrosive and dirty gas flow conditions.

All Flowseal Knife Gate Dampers utilize a rugged and heavy duty screw jack drive system to provide a positive drive to the knife gate blade in both directions. The reliability of this system has been amply proved through years of use.

Flowseal Knife Gate Dampers are designed so that all parts are field replaceable without removing the frame from the duct. Maintenance is simple and can be performed whilst the system is on line.

The following styles of Knife Gate dampers are available:

Dished Disc Dampers

Particularly suited to waste gas ducts on bagasse or black liquor plants or where gas contains fibrous particulate which could get caught up on butterfly or louvre damper blades.

Dished Disc Damper
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