Re: Conveying Electrofilter Dust By Screw Conv.
If you keep the material hot enough it will not go hard. Insulate and lag everything.
If it is very cold climate then a bit of trace heating will also be required. ■
Screw Conveying Materials That Harden
The geometry of the installation has not been described, but there appears to be two sections to the installation, the feed hopper and the conveying length. Material that sets hard should not be stored in a hopper unless emptied before it changes composition. A mass flow design discharged regularly may be satisfactory, but the operating and site conditions should be carefully considered. Screws handling products that 'cake' should receive a thorough eamination of the working conditions and environment and special design attention. Rubber casings will generally cause a set boundary layer to crack and be carried away but hard tipped, chamferred edge ribbon flights are also useful to miimise screw tip binding and clogging of the cross section. Intermediate bearings as a 'No-No' and progressive extraction and subsequent expansion of the transfer capacity is virtually essential. The wrong thing to do is to buy an off the shelf screw and expect it to work well. I would suggest that you contact a reputable supplier with experience to secure the best advice and results. ■
More Details
DEAR Lyn
Materials Are very very Dusty and fine.
Its density is about 750kg/cubic meter.
It will be lumpy and hard in screw I think because of humidity or proximity of Acids Tank.(INFLUENCE of acid,s vapor)
Screw length: 4600mm
pitch:155 mm
flight thickness:3.5 mm
shell inside diameter(tubular):205 mm
screw diameter :192 mm
Rpm:140
shaft dia:2 inches (pipe)
no hanger bearing included
screw conv. are the same in flight pitch in both horizontal and inclined situation.
Is it necessary to extend opening (input area) on the horizontal screw conv. equal to hoppers full bottom lenght?(what is the standard size of input entry?)
I wanted to put some pictures of arrangement and materials here, but I could not.(I will send You I f I have Your email Address)
Is the clearance between tube and screw enough?(6 mm)
Does not it need hanger bearing?
I want to convert its flight to cut flight with paddle.what is your Idea?
do you think I can solve this problem.?
Regards
B-A ■
Handling Material That Sets
The new information implies that there are two screw units, one under the feed hopper and another, inclined, to transport the material to a higher location. The hopper construction and length of outlet are not given, but the uniform pitch impies that this is a short opening. If the feed conveyor is running with a flooded supply and transfering to a second, inclined conveyor with the same screw construction and speed, one would expect difficulties to arise at the transfer point. The slope of the second conveyor, if there is one, is not given, but the capacity of inclined screw conveyors is very sensitive to their inclination. The speed of 120 rpm appears also very high for a screw feeder of this size and duty. If you care to email an arrangement and detail drawing of the installation to lyn@ajax.co.uk, I will try to advise in more detail. ■
Re: Conveying Electrofilter Dust By Screw Conv.
Dear Lyn
I sent you pictures of Screws arrangements.(through Your Email)
Slope of Inclined Conv. is 18 degrees.
I think the system has some problems as:
1-It is not paid enough attention to Material's Characteristic (It is assumed that materials to be conveyed are the same as CEMENT.
2-Material tends to compact in screw and makes some lumps in bin (pics 462and 474) so may be screw's blades must had another design (like cut flight, cut and folded flight, mixed flight cut flight with paddles,....)
3-Clearance between screw's blades and pipe is not enough.(6mm each side)
4-Screw pitch should change to short pitch at least in entrance and inclined screw conv.
5- Shell of horizontal conv.is pipe instead of proper TROUGH.
6-Conv. length is 4.6 m and is uniform(one piece).(More than standard length)
7-According to size and capacity (5 tph) Rpm is more than usuall.(140 Rpm).
I will be very thankful if hearing from you soon.
Best Regards
Babak-A ■
Conveying Electrofilter Dust by Screw Conv.
PROBLEM WITH TRANSFERING OF COPPER FURNACE ELECRO FILTERs DUST ( WITH SCREW CONV.)
Hi Dears
We want to carry fine dust from a static bunker through some screw convs.
the problem is that the dust will be harden after a short period after stop and we can not restart easily.(may be the dust synthesizes with Air or humudity in the air).
I will be thankful if you help me to overcome this problem.
Best Regards
Babak-A ■