Shipping Container Overfill Protection?

[tonyw3026]

I am looking for a an "add-on" system that can be used to fill containers from pails up to totes to prevent overfill. A gasoline fill nozzle might work but I cannot find one that is suitable for a range of chemicals, I need 316SS/Teflon/Viton. There also could be foam.
The containers are filled manually on a weigh scale from a pumped source. I am not necessarly looking for an accurate fill system, just something to prevent a spill when the operator goes to sleep.
I have considered an air probe (pressure or vacuum) strapped to the fill nozzle that would shut off the pump or a valve but would like help with the sensing part.
Any ideas?

 

[IFRs]

You could use a weight sensor.

Sounds like a system similar to gasoline filling station pumps - have you looked at their hardware?

 

[bchoate]

bchoate
Please clarify something for me. Are these containers shipped externally or are they filled for internal use?
You mention a container range from pails to totes. Without disclosing the material identity; is it hazardous? flammable? or combustible?
If these are shipments to customers, then I am assuming that you are aware of and complying with transportation requirements of CFR 49. Outage requirements for non-bulk packagings include a) drums and pails are not to be liquid full at 55 C (131 F)for materials listed in Table 172.101 of CFR 49. Bulk packages (totes) are to have 1% outage at 46 C (119 F)if uninsulated.
If these are shipment packages, then the desire to prevent spills but not achieve an accurate fill is a concern.
A simple, controlled container filling station can be constructed using a weight scale (4' X 5' Toledo), a control system, a control valve, and necessary piping and hoses. Since you have several container sizes and several chemicals to package, a system in which the operator can choose an appropriate recipe is needed. This can be accomplished with with a small PLC such as AB's SLC 500 series and a panelview to create recipes and inputs to the PLC. Calculate weight of each product for filling a given container. Select how fast to fill each container (this will set the trim for the control valve). The PLC should be programmed to fill the container to about 95% of target then reduce the feed rate to a final trickle feed to compensate for inflight material. The PLC will close the control valve when the target is reached. An actuated valve can be installed in the feed line to be shut off as a safety when the container is filled.
Further help with this system or others may be found with FRS Technologies, Longview, Texas (rfangman@cablelynx.com)

 

[tonyw3026]

Thanks bchoate
The containers are for external shipping and the contents can be hazardous and combustible. We are satisfied with the filling accuracy/outage issues. This is really a safety question to prevent the operator being sprayed if he doesn't watch the weigh scale digital readout. We have a PLC filling system in another area similar to the one you suggested.
I am just looking for a robust level sensor system that can be moved with the filling nozzle from pail to pail or drum to drum. Once I have a level signal then I can trigger a valve or the pump to stop filling.
A gasolene filling nozzle would be even better if I could get one in 316SS.

 

[bchoate]

bchoate
Thanks for the info. I'm not trying to be difficult but the issues seem to be the same. Hypothetically lets assume that there chemicals A, B, C, & D packaged as 1 gal., 5 gal., 55 gal., and tote quantities. Questions I would ask about the system are: 1) Is the 1 gal. container filled to the same volume for A, B, C, & D. Similar question for the remaining package sizes. My experience is that fillage probably varies several pounds dependent upon physical properties and outage limits.
The most simple scenario is that there is one level only for each of the package sizes independent of the chemical. The operator has to set the controls for the target level in each container or 4 settings in this example. The operator's choices increase if different chemicals require different levels for a given package size. The nozzle approach appears to assume a single height for each package size. The nozzle approach presents two concerns; a) most nozzles have high flow rates and splash back could be a problem and b) nozzle shutoff based on back pressure may not coincide with desired outage.
The easiest gage of fillage is still weight. The pallet scale terminal can be set for a target alarm weight by the operator. Momentary switches can be used to open an actuated ball valve and the terminal alarm can close the valve. I don't know of any level indication methods that will be as easy to implement.
Bill C

 

[tonyw3026]

I guess the key point is that I am only looking for a safety shut off system, not an exact quantity shut off. If the gasoline nozzle was mechanically suitable then the operator could either a)lock the trigger open, leave the nozzle in the container (with the tip below the required final level) then after it shuts off, top up the required weight manually, or b) hold the nozzle all the time and fill to the required weight.
In both cases the overflow would be prevented as long as the nozzle and sensor tip is below the top of the container. There could still be a blow back but only if the operator holds the nozzle/sensor tip JUST below the top of the container and holds the nozzle wide open.
This is exactly what we all do with our gas tanks and it is rare to get more than a minor splash back. If you go into a "we serve" gas station they normally lock the trigger and walk away from your vehicle and this works quite well.
I would love to install a better accurate filling system but there are other constraints in this case (like financial). I will keep looking for a shut off fill nozzle for a bit longer.
Thanks for the discussion.

 

[IRstuff]

How is the nozzle placed on the container? Does the operator hold it or is there some sort of bracket?

In either case, although the latter would be preferrable, you could perhaps install a pressure switch that would shut off if the level of the material rose past the tip of the nozzle.

Although you're not able to use a gasoline nozzle, you might be able to adapt the auto shutoff that all gas pumps have.

TTFN

 

[bchoate]

bchoate
The largest supplier of fueling nozzles is OPW. Most of their nozzles are aluminum. They do have #11 models that are nickel plated. I have not found any SS components.

 

[unclesyd]

There were S/S automatic drum filling nozzles available. They were not hand held but were used for automated drum filling. We used them in combination with weigh scales to fill 55 gal drums and totes. We no longer used the system so it’s a little hard to get information as to the manufacturer.
I’ll keep trying to find out who made them.