check for back pressure in the silo due to non-functional ven filter

moisture in the material can decrease discharge rate from trailer ■

Sod. Carbonate is hygroscopic and will absorb moisture and cake. 5.6 % moisture is high for this material it will cake with time. Check for caking ! in the hopper truck before discharging. ■

Mr. Hilbert and Mantoo are correct in their findings, have you inspected the inlet air filters for their age and condition FOR PLUGGING and reduced inlet air flow.

If dual filters are used they both must be changed!!!!!!!!

Never mind if the HG gauge on the filter housing says the filter is fine after reseting it-do not trust it for testing.

When was the last time it was changed out for a new one?;-air volume is the key to your problem; can you obtain a Delaval milk house gauge kit to verify your blowers output at you location above sea level. That is the best way to handle this and work backwards after that- find your nearest Delaval milking equipment dealer and purchase one of these kits/sets and follow the directions for testing your blower and you will have your answer to at least one part of the puzzle.

Are you properly venting the trailer to alllow for material flow to the bottom of the discharge cones and common discharge pipe?

You have made no mention of the loading hatches and their seals; what shape are they in?, Are the hatches warped?, Is the trailer possibliy racked/twisted and distorting the tanker and its linear hatches and sealing ability?

I would suggest a low pressure smoke test for the trailer, piping and silo to check for sealing properties.

A blower of any type can be worn significantly and still generate low pressure and volume.

When was the pressure regulator for the blower checked for wear and sealing ability? testing it there is the starting point and work your way back to the blower through the system.

Regarding the silo and filter bag: how is it configured in the system? A hatch with the bag exiting the silo during filling from the tanker? is there a relief regulator/check valve plumbed into the filter bag to release pressure during silo loading?

If so do not forget that generally fail first-if it appears worn on the inside from air flow and debris/or has a weak regulator valve-little or no resistance to turning- the spring is shot or sealing surfaces are nearly gone.

You really have not discussed the blower at all; has any maintenance been perfomed on it?, has the oil level been checked in the gear box?, If it is belt driven are the belts tight or too tight?, this will bind the bearings and effect efficiency of the blower.

If it is direct drive off an engine with a power take off it is possible the clutch is slipping against the load-please tell me more

If the blower is a vane type is it possibler the vanes are worn- this sounds more and more like the problem but until the blower is tested and or repaired all is for naught.

You have left me with more questions than answers and I need more information. ■

Dear Ham,

It seems that something changed in the pneumatic conveying properties of the soda ash.

It could be the moisture content and/or the particle size distribution.

Both properties (can) lead to a higher suspension velocity.

That will result in sedimentation in the pipe line and consequently to a lower capacity.

Can you connect a second bulk truck to the conveying pipeline as a booster (f.i. inject the air in a bend) right after the loaded truck.

(A small rented compressor with pressure reducer will also work)

Be careful that the silo and the filter as well as the safety vent can handle the extra air and possible surges.

The booster truck valves should be always open and the compressor can be varied in rpm to find the optimum settings.

I had this kind of experience once with very poor flowing cement

success ■

OK now that you are trying to herd cats which in itself is a useless entertprise:

How often is the interior of the trailer piping cleaned with a steel brush?

If you are not using a common drawdown pipe below the cones that tells me you have mass flow problems because all the pressure generated by said blower is pushing against the entire surface area of the soda ash in the trailer so of course you have a problem due to the material closing in on itself/compacting rather than having a take away pipe drawing the material away from the dicharge cones.

Is it possible to aerate the cones during or prior to off loading say with an air lance pushed into the bottom of the cone somewhere or attaching an airline to the bottom ogf the cone with the hatches open to force air throught the mass in the cone? with out a picture or band name of the trailer I am stuck.

If you have a picture of the trailer it would be helpfull but from here it sounds more and more like a compaction of material boondoggle.

The effort here tells me the material is compacting prior to discharge simply from road transit etc.

regarding the regulator/relief valve was it totally rebuilt with new wear surfaces and springs? when ever we had problems the valve was replaced with a new one due to its low cost.

One other thing in the cat herding department:

Are you using a flexible hose for discharge to the silo?, if so it sounds as if the inside of the hose has collapsed with out its showing through to the exterior-the inner carcass has separated from the outer carcass and reinforcement wire/spring steel if used.

Hello Teus,

I hope all is well, the weather here on my side of the pond is cold and rainy for the begining of july-reminds me of the summer of 1983 with temps in the thirties fahrenheit for most of the month.

leon Z ■

Hello,

With only 150HP the GM90S would only be conveying around 50 inlet m3/min assuming 1 BarG back pressure. Since that is at the low end of the blower RPM this can raise the discharge temp above 140C at ambient temperatures above 35C. Is the an after cooler installed on this system? Though unlikely, it is possible for moisture to drop out after the cooler (depending on type and presence of a water knock-out). This could speed up material caking up on you.

The machine is rated for up to around 90 m3/min and 250BHP; getting more air is possible made difficult by having to change motor and drive. ■

Dear ham,

In your original post you report

“quote

The action plans we executed were cleaning of convey line

“unquote

Now you find the pipe is clogged !

The question why the problem just occurred and was not there in the past still remains.

That you did not experience any pressure rise could be a result of setting bypass valves of the truck on each unloading.

May be the clogging is the result of another problem and if so it should reoccur (Which it did not in the past)

Keep us posted on the development.

We want to know.

Have a nice day.

teus ■

I agree with Teus completely,

and adding a 4 inch white

neoprene pipeline barbell pig

to your shop tools is a good idea/necessity ■

ham,

as requested,

here is the picture of the clogging of the convey line.

after the declooging.we were able to unload 1 hopper truck (18MT) of soda ash in 1hour 45 mins which is our normal rate.

the clog is in between the vertical pipe,the morris coulpling and the elbow above the 30m silo.

all,

what could have caused a clogging in a vertical pipe line?

Attachments

dsc00996 (JPG)

■

Impact of the material against itself and build up from compaction during transfer, also heat of friction-material grinding against itself; All the more reason for a pipeline pig.

lzaharis ■

Since you have mentioned that the plug is in the vertical pipe shouldn’t that rule out the impact related build-up.?

I think there is more to it. ■

Hello,

The I think Teus was onto something when he said that your material density as well as moisture content are suspect - not necessarily the conveying system layout.

If the GM90S is a stationary unit feeding into the bulk truck, please not only check the blower package pressure relief valve, but also that of the trucks for blowing off as a new plug ocurs. ■

dear ham,

Looking at the picture, could it be that the morris coulpling was (is) leaking?

take care

teus ■

teus,

looking back from our maintenance records,we found out that the morris coupling was serviced a year ago due to powder puffing.

the duct tapes could have deteriorated causing rain water intrusion.

the aluminum duct tapes have been replaced,however we havent replaced the flexconn yet.

we are now implementing a timely inspection on convey pipes including morris couplings and flanges.

how could we prevent water intrusion in our morris couplings?

thank you so much for helping us resolve this issue.

himex ■

Hi Himex,

The private messaging system is still busted and I have lost hope it will ever get fixed. I see that you tried contacting me. Here is my regular e-mail address: rweiser@aerzenusa.com

Take care and have a great week. ■

Hi Ralf (and others)

If you try to open the message in the forum, it is correct that it does not work the correct way

(This has been the case for quite some time now)

But, when you select the message and then click on FORWARD, then you can read it.

Have a great week also

Teus ■