Rotary Dust Valves

'Floating Seal' Type HDFSCI - Sizes 150, 200 and 250mm

Rotary valves using the ‘revolving door’ principle have long served as dust valves and dust feed regulators. In conventional valves of this type the seal is obtained by soft rubber or plastic wipers - attached to the rotating vanes that form the pockets. These function well when the dust is at or slightly above ambient temperature and when the dust is not too abrasive. However, many installations must function at elevated temperatures and / or with the abrasive materials.

The Type HDFSCI (heavy duty cast iron) Floating Seal Valve has been applied successfully to this service. Soft wiper materials are replaced by a carefully machined cast iron ‘floating seal’ of controlled hardness. The floating seal has been designed that that it has the ability to operate at temperatures as high as 400 degrees celsius.

The hardness of the rotor is greater than that of the seal. Hence a perfect metal-to-metal seal is continuously maintained as the cast iron seal slowly wears away. The weight of the seal keeps it in intimate contact with the rotor.

The Type HDFSCI ‘Floating Seal’ dust valve may be supplied as a bare shaft unit (i.e. no drive) or complete with electrically driven gearmotor, as a direct drive or chain driven unit.

VALVE CAPACITY

All dust valves capacities are rated in m3/hr. If this is not directly available, the capacity may be calculated from:

 

A)
  • Known dust load in kg/hr
  • Known dust bulk density in kg/m3.

To obtain capacity, divide dust load by bulk density.
e.g:  Dust Load    =  1800kg/hr
       Bulk Density =    600kg/m3

Capacity  = 1800 kg/hr =  3 m3/hr
                  600 kg/m3
 
B)
  • Known dust load in g/m3 *
  • Known dust flow in m3/hr *

To obtain capacity, multiply dust load and gas flow and divide by 1000 to give kg/hr.

Then proceed as in A) above.

e.g: Dust Load  =  12g/m3
       Gas Flow   =  150,000 m3/hr

Load = 20 x 30,000/1000 = 1800kg/hr

Then from A) above capacity  =  3m3/hr

Once the capacity in m3/hr is established, the appropriate size value and speed may be selected from the following table.
 
* Note: Both dust load and gas flow must be in the same terms, 
for example, g/Nm3 and Nm3/hr OR g/Am3 and Am3/hr. 

 
CAPACITY

In selecting a valve to suit the required capacity it is preferrable to select the lowest speed compatible with requirements. Capacities given are for typical speeds generally available, other speeds are available.

Valve capacity is a function of the dust flowability such as hopper valley angle, type of material, angle of repose etc, much of which is not known. The speed of the valve also determines rate of material fall into each pocket. Two capacity tables are given, one based on theoretical 100% capacity, the other based on an empirical figure of 65% capacity from previous experience.
 
 

 

VALVE CAPACITY

VALVE FLANGE SIZE

SPEED
R.P.M.

 150MM 200MM 250MM
100% FULL
m3/hr		 65% FULL
m3/hr		 100% FULL
m3/hr		 65% FULL
m3/hr		 100% FULL
m3/hr		 65% FULL
m3/hr
9 1.89 1.23 5.83 3.79 11.88 7.72
14 2.94 1.91 9.07 5.89 18.48 12.01
20 4.2 2.73 12.95 8.42 26.4 17.16
25 5.25 3.41 16.2 10.53 33.0 21.45

 

: Back :     : Home :     : Print :