Dear Franc,

Have a look at

http://www.trelleborg.com/en/Industr...uck-discharge/

Success

Teus ■

Originally Posted by Franc

Hi.

I am a young engineer at a laundry products mfg plant (this is actually my first job).

This is the first time that I've been exposed to technologies such as pneumatic conveying.

The process that I own is powders unloading via positive displacement, that is from hopper truck to surge bin.

I'm having issues with the life of our material discharge hose.

It is frequently damaged, powder leaks from tears near the cam.

Replacing it every time is too expensive, and more importantly, we want to prevent leaks in compliance to environmental regulations.

Here are the hose's specs and usage condition:

It is made of stainless steel and is braided.

Operating pressure is 10-11 psi.

Blower air discharge temperature can reach up to 115 degrees C at most.

Material conveyed is calcium carbonate.

Because the hose is heavy 2 operators attach the hose to the hopper truck and hammer it into place.

My question is this:

Can I replace the hose with a different type?

I would prefer it to be light and easy to install.

Of course, we need to consider

a. the material being conveyed (calcium carbonate)

b. operating pressure (normally 10 to 11 psi, max 13 psi)

c. temperature

Thanks for the help!

=================================================================================================

It seems that the hose you are using does not have an inner liner. Braided metal hoses are provided with an inner liner to prevent powder leakage. You can get this hose from several vendors such as HOSECRAFT USA. Description of their hose is given below.

"The Model SI3 hose is a stripwound interlocked stainless steel hose with a smooth bore for ideal material handling. It is relatively lightweight but tough. A special liner is used for creating the smooth bore.

This metal hose is also available in galvanized steel, bronze, and monel, and in a packed version. Commonly provided with any style of carbon or stainless steel, or aluminum fittings, such as camlock & groove type.

Also available in a galvanized material as a value option.

Temperature range is -50F to 1200F."

Be sure that you are using proper hose connections.

Amrit Agarwal

Pneumatic Conveying Consulting

email: polypcc@aol.com ■

Originally Posted by Franc

Hi.

I am a young engineer at a laundry products mfg plant (this is actually my first job).

This is the first time that I've been exposed to technologies such as pneumatic conveying.

The process that I own is powders unloading via positive displacement, that is from hopper truck to surge bin.

I'm having issues with the life of our material discharge hose.

It is frequently damaged, powder leaks from tears near the cam.

Replacing it every time is too expensive, and more importantly, we want to prevent leaks in compliance to environmental regulations.

Here are the hose's specs and usage condition:

It is made of stainless steel and is braided.

Operating pressure is 10-11 psi.

Blower air discharge temperature can reach up to 115 degrees C at most.

Material conveyed is calcium carbonate.

Because the hose is heavy 2 operators attach the hose to the hopper truck and hammer it into place.

My question is this:

Can I replace the hose with a different type?

I would prefer it to be light and easy to install.

Of course, we need to consider

a. the material being conveyed (calcium carbonate)

b. operating pressure (normally 10 to 11 psi, max 13 psi)

c. temperature

Thanks for the help!

OH BOY;

Every curve and every elbow is your enemy!!

Friction in transfer is your enemy as well as the stainless steel weaving of the hose.

A standard steel wound fire hose suction line with rubber inner carcass may solve the issue quickly but you need

to have a hose company representative come look at your place sometime if the items I mentioned below are not the issue.

A quick experiment with an 8 foot purchased section of stiff bendable fire hose suction line from a fire appliance supply house will provide a lot of answers quickly to you for this issue.These fire hoses typically come withe the cam lock female ends already attached.

You should also purchase a number of pipeline pig balls to clear the line of any blockages that may be present that are there as you will always have an issue with siltation build up of fines in long pipe sections and elbows.

I was wondering???

Is the pnematic tanker the source of the pressure gradient to transfer the material from the pneumatic tanker to the surge bin/silo?????????

Does your employer own these pneumatic tankers??????

How well are these trailers maintaned?????? if they are not taking care of them they are not helping the process.

Please tell me you refer to this in terms of pressure gradients ONLY!!!!!!!!!!

Do you have access to a Delavan Milk house Vacuum Gauge Kit to test the efficiency of the blowers?????Do you know how to use one?

They have to be used to properly set the pressure gradient created by the delivery system taking into account the altitude of your location in relation to sea level.

NO, YOU DO NOT DARE SAY the Hg Gauges mounted on the filter housing and air delivery lines are what we depend on!to examine the blowers efficiency!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!They lie like rugs on good days!!!!!!!!!!!!!!!

IS this hose built in house with purchased parts???????

If so, do you stick them in a freezerfor a few days to shrink the male barbed ends before inserting them and banding them to the steel hose?????

If their is no rubber for the barbed ends to dig into thats a huge issue because the barbs will weaken the stainless over time as there is no socket.

Blower type?

Continuous positive Radial Vane Type

Positive Displacement Rotary Lobe ROOTS type

When was the last time the inlet air filters were changed?

Has the lubrication oil level on the blowers gear box been checked lately?????

If you have that much heat you may have problems on the suction side of the equation.

Is/are the trailer(s) fully vented? Are you sure?

Are you suctioning the entire length of the trailer or only sections at one time?

It is better to suction only one part of the pneumatic tanker at a time if you have ball valves in the suction

line to segregate the tanker sections while unloading.

How clean are the pneumatic tankers discharge lines???????

Are these tankers used only for calcium carbonate or are multiple products like salt and or cement also transported

in these pnuematic tankers?

Are the transfer pipes in the tanker belly flushed with air and pig balls or pipe pigs????????????????????????????

Are you using a dilute phase or solid phase transfer?

if you are not using dilute phase that may be ninety percent of your issues.

If you have to hammer those cam locks into place they ARE NOT CLEAN!!!!

Hammering the hose will also cause damage to the portion of the hose attached to the female cam locks.

Use hot water, hold the hose ends in a bucket of hot water, a wire brush to clean the hose conections and the grooves on both ends and use rags to dry them off.

Dont forget the calcium carbonate is also a moisture attractant hence the dust issues.

What is preventing you from using short flexible steel reinforced fire hose sections with additional steel pipe sections to the silo??????????

Are you using or have you used pipeline pigs or pipeline pig balls to clear the discharge line into the silo? if not you need to invest in a small herd of them as they are not that expensive AND they should be used at the end of every delivery.

You will need to install an additonal elbow and ball valves to launch the pigballs and an elbow and ball valves to divert and to catch them before they enter the silo/surge bin UNLESS the bin is emptied periodically and fresh air is blown into it to provide a breathable atmosphere. ■