Static problems

[TRA]

al, by the sounds of things, you should stick to concrete. Your trying to BS your way around everything is getting old. Feel free to paste this in your response.

You talk of an "earthed wire", just where do you think 99.999999999999999% of them are connected?

Your attempted analogy's are FOS. Really desperate as a matter of fact. "Static, Water, Fuel",,,,,,,really,ROFLMAO I'll remember that next time in the pool, or stick my finger in a gas tank.

Here al, it don't get much simpler than this....

Grounding Aircraft
During refueling fuel is transferred from the fuel truck or underground tanks (sometimes above ground) and this process can cause a static charge to build up between the aircraft and fueling device. This is the same principle as walking on a carpet in wintertime and getting a shock from the doorknob when opening a door.

Testing has shown that when people 'feel' this shock the voltage is at least 3500 V. Amperage is very low so no real power is transferred and no harm done, but it can be uncomfortable though. Delicate electronics or aircraft avionics can be 'killed' by voltages much lower than this.

Static Electricity
According to Wikipedia the definition of static electricity is as follows:

"Electrostatics (also known as Static Electricity) is the branch of physics that deals with the forces exerted by a static (i.e. unchanging) electric field upon charged objects. Electrostatics involves the buildup of charge in objects due to contact between (generally) nonconductive surfaces. These charges are generally built up through the flow of electrons from one object to another. These charges then remain in the object until a force is exerted that causes the charges to balance e.g. the familiar phenomenon of a static 'shock' is caused by the neutralization of charge built up in the body from contact with nonconductive surfaces."


Static buildup
It is important to understand how static electricity is build up. As in aircraft operations like refueling this can create dangerous situations. An aircraft flying through the air can also build up static charges. To discharge these build up electrons special devices are attached to ailerons and tail feathers to return these electrons to the surrounding air and they are called 'static wicks'.

Without these so called 'static wicks' an aircraft would experience radio and navigation difficulties due to static discharges on the outside of the aircraft.

Fuel (dis)charging
When an aircraft is refueled fuel is pumped from one container to another and throughout this process the fuel charge level is determined by several factors: pump rate, temperature and humidity. This charge is build up between the two containers. When the charge is high enough to jump between the containers, a spark will occur. If there is a combustible mixture near the spark (above/near the fuel cap) a fire or explosion could happen. And this is the reason why a ground wire is connected from the fuel station to the aircraft whenever fuel is being transferred.

Defueling
There are two area's where a pilot should exercise caution when transferring fuel. The first is when draining an aircraft tank. During this draining fuel is transferred and a charge can build up. Connecting a ground wire from the aircraft to the fuel container makes sure a voltage differential cannot develop and eliminate the change of a spark from aircraft to container.

Just remember, when you are draining fuel, there can be enough air in circulation so that the fuel/air ratio is in the combustible range. And one spark can do the trick..

Fueling
The second problem area is the filling process. Many fuel stations use a ground wire when refilling an aircraft and this is good. But when the aircraft is refueled from a barrel or drum this ground wire is nowhere to be seen. Here a jumper cable can be a good safety precaution to assure that any static charge is dissipated before it can build up.

If you use a metal jerrycan with a metal or otherwise conductive funnel (Mr. Funnel) make sure the aircraft, funnel and container are touching each other during the refueling process. Any static buildup is not possible then.

Metal containers dissipate the electric charge easily. Plastic containers usually not, unless they are made of conductive materials. We recommend the use of metal containers with a good jumper wire. It is so much safer.

Static Discharge Reels

At an airport fuel station you will normally find an static discharge reel. Static discharge reels are designed to provide safe and reliable grounding of containers, equipment and vehicles. These reels provide grounding or bonding to prevent static electricity build up in airport sensitive areas.

You will find these reels in many different variants. And using them is easy, grab the large connector and slowly walk to the aircraft while unwinding the reel with the cable. Connect the wire to a conductive place (exhaust will do fine) or to a dedicated aircraft ground connector but not on a painted tiedown ring. Disconnect the ground cable when finished refueling the aircraft.

PS: Do not forget to remove the cable when refueling is finished, you wouldn't be the first...

 

[Boyd Allen]

Correct me if I am wrong.

It is my understanding that in order for a static charge to be created on an object, it has to be insulated from ground, and that connecting it to ground will discharge the static charge. When this connection is made, it should not be done is such a way that no flammable materials or vapors would be exposed to a spark that may happen when the connection is made, Inattention to this precaution could cause a fire or explosion.

If I go to the service entrance/breaker panel, that feeds my house, and take off the plate that covers the wiring to the breakers, and the bus bars that they are connected to, I will see that there are three copper bars, buss bars. The two on the outside are "hot" and if a voltage meter is connected to both, it will show 220V (single phase). The center bar is neutral. It is connected to a wire that runs to a grounding stake so that there is no charge difference between it and the earth. Voltage measured between this bar and either of the hot bars will be something on the order of 110V. Further examination of the neutral bus (connected to the earth) will show that it also is connected to the white wires that pair with the black wires that come from the circuit breakers, completing an AC circuit when a load is connected, by switch or being plugged into an outlet. Also connected to the neutral bus bar are the bare wires that connect to the grounding sockets of outlets that take three prong plugs, I believe that there is also continuity ( a connection between) between it the outlet mounting tabs , and the threaded hole where the cover plate screw is threaded. So we see that ,if my house is properly wired, the screws that retain outlets' cover plates are connected to the earth. They are grounded. It would seem therefore, that anything that is connected to these screws would also be grounded. If I were going to do this, I would test the particular location that I was going to use, with a voltage meter, to make sure that it was correctly wired. I realize that this may be of limited utility for fueling airplanes, but I can live with that. There are variations in wiring practice. In some situations conduit is used; when it is, it is supposed to be grounded. In some cases there may be green equipment ground wires, that are also connected to the neutral bus. I should add that I make no claim to expertise, nor am I making any recommendations about making electrical connections of any sort.

 

[alinwa]

al, by the sounds of things, you should stick to concrete. Your trying to BS your way around everything is getting old. Feel free to paste this in your response.

You talk of an "earthed wire", just where do you think 99.999999999999999% of them are connected?

Your attempted analogy's are FOS. Really desperate as a matter of fact. "Static, Water, Fuel",,,,,,,really,ROFLMAO I'll remember that next time in the pool, or stick my finger in a gas tank.

Here al, it don't get much simpler than this....

Grounding Aircraft
During refueling fuel is transferred from the fuel truck or underground tanks (sometimes above ground) and this process can cause a static charge to build up between the aircraft and fueling device. This is the same principle as walking on a carpet in wintertime and getting a shock from the doorknob when opening a door.

Testing has shown that when people 'feel' this shock the voltage is at least 3500 V. Amperage is very low so no real power is transferred and no harm done, but it can be uncomfortable though. Delicate electronics or aircraft avionics can be 'killed' by voltages much lower than this.

Static Electricity
According to Wikipedia the definition of static electricity is as follows:

"Electrostatics (also known as Static Electricity) is the branch of physics that deals with the forces exerted by a static (i.e. unchanging) electric field upon charged objects. Electrostatics involves the buildup of charge in objects due to contact between (generally) nonconductive surfaces. These charges are generally built up through the flow of electrons from one object to another. These charges then remain in the object until a force is exerted that causes the charges to balance e.g. the familiar phenomenon of a static 'shock' is caused by the neutralization of charge built up in the body from contact with nonconductive surfaces."


Static buildup
It is important to understand how static electricity is build up. As in aircraft operations like refueling this can create dangerous situations. An aircraft flying through the air can also build up static charges. To discharge these build up electrons special devices are attached to ailerons and tail feathers to return these electrons to the surrounding air and they are called 'static wicks'.

Without these so called 'static wicks' an aircraft would experience radio and navigation difficulties due to static discharges on the outside of the aircraft.

Fuel (dis)charging
When an aircraft is refueled fuel is pumped from one container to another and throughout this process the fuel charge level is determined by several factors: pump rate, temperature and humidity. This charge is build up between the two containers. When the charge is high enough to jump between the containers, a spark will occur. If there is a combustible mixture near the spark (above/near the fuel cap) a fire or explosion could happen. And this is the reason why a ground wire is connected from the fuel station to the aircraft whenever fuel is being transferred.

Defueling
There are two area's where a pilot should exercise caution when transferring fuel. The first is when draining an aircraft tank. During this draining fuel is transferred and a charge can build up. Connecting a ground wire from the aircraft to the fuel container makes sure a voltage differential cannot develop and eliminate the change of a spark from aircraft to container.

Just remember, when you are draining fuel, there can be enough air in circulation so that the fuel/air ratio is in the combustible range. And one spark can do the trick..

Fueling
The second problem area is the filling process. Many fuel stations use a ground wire when refilling an aircraft and this is good. But when the aircraft is refueled from a barrel or drum this ground wire is nowhere to be seen. Here a jumper cable can be a good safety precaution to assure that any static charge is dissipated before it can build up.

If you use a metal jerrycan with a metal or otherwise conductive funnel (Mr. Funnel) make sure the aircraft, funnel and container are touching each other during the refueling process. Any static buildup is not possible then.

Metal containers dissipate the electric charge easily. Plastic containers usually not, unless they are made of conductive materials. We recommend the use of metal containers with a good jumper wire. It is so much safer.

Static Discharge Reels

At an airport fuel station you will normally find an static discharge reel. Static discharge reels are designed to provide safe and reliable grounding of containers, equipment and vehicles. These reels provide grounding or bonding to prevent static electricity build up in airport sensitive areas.

You will find these reels in many different variants. And using them is easy, grab the large connector and slowly walk to the aircraft while unwinding the reel with the cable. Connect the wire to a conductive place (exhaust will do fine) or to a dedicated aircraft ground connector but not on a painted tiedown ring. Disconnect the ground cable when finished refueling the aircraft.

PS: Do not forget to remove the cable when refueling is finished, you wouldn't be the first...

I'M grasping???

you're a funny guy....

I guess if this wiki stuff constitutes your "rebuttal" then wheeee, you've really made your point.

al

 

[K Hope]

Al

Does the ground work?



Boyd

A couple of examples of Static build up.

Pouring powder from one plastic bottle into another plastic bottle.

Rubbing of powder over each other and over measure and components.

Contact - with residual ES charged surfaces.


A couple examples of factors affecting drainoff .

The powders size, shape and its surface coatings.



Ken

 

[Boyd Allen]

Ken,
Good points...I find that older measures, with a coating of graphite on the interiors of their plastic reservoirs have fewer static problems. Maybe I need to take a note from the old Belding and Mull measures and start fitting tubular brass powder reservoirs to my new measures. I notice that the new measures are designed for black powder use aluminum.

 

[TRA]

al, your arrogance never ceases to amaze me.

In the example I posted there was a lot of common information in it for someone savvy enough to understand what it said. Your a contractor, have you ever refueled anything in the field, in the military, anything? You connect,"Bond", ie "Ground"-- the, device, and the, equipment, together to keep a hazardous discharge from occurring, not for the reasons you are suggesting.

Nowhere will you find any recommendations to ground, nor did the example posted, suggest you "Ground" the vehicle to anywhere but the refueling device. Where will the majority of the readers go to connect to a ground as you have suggested??????????
Boyd has already spoke of his "Electrical Service"

Your clothes dryer "should" be grounded as you say------yet the clothes come out full of static------maybe you should have some of those cables by your dryer. ROFLMAO

The next time your wife has the clings, just have her stick her finger in the electric outlet. Or you could jab her, in the... with one of your cables.

al-----your attitude and arrogance stands in the way of you actually learning something, you have a lot of folks fooled, and hopefully someone doesn't get shocked, or worse, doing what you suggest.

SURVEY SURVEY SURVEY How many of y'all actually tried to ground your powder measure, like prince albert has proclaimed,,,,,,,,,,,AND,,,,,,,,, what was your result? It's OK to be honest.

 

[Frank B]

I wasn't going to reply to this thread because it has become a pissing match but. The poster above that said to wash your plastic measure measure and tubes hit the nail on the head. The paragraph below will explain. It is no accident that almost all powder containers are a special black plastic that's purpose is to prevent static build-up. Hope this helps. Later! Frank

For example, adding surface conductivity to plastics will move them up into the higher conductivity range and prevent the build up of static electricity that is caused by friction. This is normally accomplished by use of additives such as moisture and anti-static sprays. The average anti-static spray is made up from a soap based material that's been diluted in a solvent, such as mild alcohol. A fire retardant is added to combat flammability of the solvent. A short time after contact with your material, the fire retardant and solvents evaporate leaving you with a conductive coating on the surface of the material. The plastic has now become conductive and as long as this coating is not disturbed, it will be difficult to generate static electricity in this material.

 

[Boyd Allen]

Frank,
We had a perfectly good pissing contest going her, and now you have ruined it with useful infromation.....and to make things worse, your post is brief and totally on topic.Get with the program. Redeem yourself. Say something nasty and personal.

 

[wolf gray]

Frank,
We had a perfectly good pissing contest going her, and now you have ruined it with useful infromation.....and to make things worse, your post is brief and totally on topic.Get with the program. Redeem yourself. Say something nasty and personal.

Yeah, Frank, what Boyd said ! "Comedy is in the eye of the beholder"- a direct quote from that famous static scientist Leanardo de Caprio!

Best,
Dan Batko

"Where are we going and why am I in this basket?"

 

[alinwa]

Al

Does the ground work?







Ken

Yes.

Also, I agree completely with the post by Frank B. The idea here is to get the charge (imbalance) to drain away (balance) and the use of "dryer sheets" or another form of conductive coating can be very helpful. The function of the coating is to make the NON-conductive plastic parts somewhat conductive.


Generally speaking, the graphite used in modern smokeless powders serves as a conductor which works well as long as the powder contacts a metal surface. In the case of the Harrell measure referenced I've got my "grounding wire" or "earthing wire" connected to the center screw of an adjacent outlet.

In the case of the Chargemaster the problem generally occurs as the powder hopper gets low. The clear plastic sleeve is isolated from the metallic powder screw. Scrubbing the plastic parts with "Bounce" or another brand of 'anti-static cling" product can help to restore conductivity. Or fill the hopper up. OR, as Francis mentioned just use the thing enough to get it nicely coated with graphite.

In one of my posts I used the term "choke point." This is imprecise, but descriptive. IF powder is hanging up in the neck of a case held in your hand then the problem is that you've "built a charge" in your body. The imbalance occurs between the case and the powder being dispensed. And IF the powder dispenser is "grounded" then you must also ground yourself. This is how wrist straps work for use while working on electronic stuff. They act to keep YOU from gaining potential. Anyone who lives in a cold climate experiences this. You walk across the room which causes you to take on a load of electricity and when you reach over to turn out the light and, WHAPP, you get a "static discharge" from the light switch to your knuckle.

This does not indicate any fault in your electrical system. Nor will you "get shocked" anywhere on the planet by using the earth as your neutral even though it's "part of your electrical system."

al

 

[alinwa]

To TRA,

TRA I'm sorry if I've been arrogant. this is not my intent. I'm not interested in a pissing match. I'm happy to learn from you if you've something to teach.

But it is my opinion that your posts are incomplete. That it is you who could get someone in trouble with your methods.

Let's start with fueling. YES, I've done some fueling. and I've got a small diesel fueling setup at my home. Your post is partially complete in that YES you must ensure a balance between two disparate containers of flammable material lest a chance discharge ignite your flammable material. We agree here. But you must also ensure that the container(s) are neutral to the "ground," ie the surrounding area. My tanks are connected to the earth by dint of the fact that the gantry is metal, steel, it rests on the ground. It CANNOT build a charge because it's not isolated. Therefore if I connect my rig to the tank it discharges thru the tank to become neutral to the tank AND THE GROUND. Transferring fuel between rubber tired vehicles presents another challenge..... a rubber tired rig IS isolated from the earth so that it can build potential. You can hook two units together, transferring fuel merrily (and building a potential charge via friction) and then when the operator steps over and grabs the handle it can spark (discharge to the earth.)

Tanker trucks driving down the road will have chains dangling down to the ground..... this is to continually drain the generated electrical charge into the earth.. And when they are loading or unloading from a ground-based tank or station the TANK is securely and redundantly grounded so you then hook the truck to the tank and discharge the truck through the grounding buss of the tank. YES, this can be termed "bonding" but the key is, not only are you bonding the truck to the tank but the tank is neutral to the ground. The real reason that there's no rhetoric in place about "bonding your vehicle to the tank AND THE GROUND" is because you don't have to. The work has been done for you. The thinking has been done for you. The TANK is well and truly GROUNDED and too much information serves only to confuse the average redneck.

The only place where it's safe to just strap the two rigs together is in an air-to-air refuel. planes do build tremendous electrical potential. They have wicks trailing off the wings and fusilage which drain a lot of the stray electricity back into the atmosphere but never would two flying aircraft be "neutral" to each other unless they're physically looped together or as you state "bonded." And when a plane lands it must be discharged into the ground before fueling or deplaning can occur. It's not uncommon for a landing plane to have a "charge" or "potential" or in other words a difference of 100,000 volts relative to the earth. Even when tied down planes must be "grounded" to the earth.

As far as your snide remarks about the clothes dryer and the wife and all..... I'll just let all that be for now. Except to note that while the dryer is grounded, even the barrel is grounded, clothes are a poor conductor of electricity. Hence "bounce" sheets to allow the clothes to drain residual charge.

As far as your assertions that one could "get shocked" by hooking to the in-place grounding system in an average home I'll also leave this alone unless you really want to EXPLAIN how grounding anything could be dangerous..... If I really am dispensing inaccurate information I'd like to be shown.

al

 

[Swamp Fox]

For your consideration...

http://www.youtube.com/watch?v=-5Z5yAeO3dw

 

[alinwa]

For your consideration...

http://www.youtube.com/watch?v=-5Z5yAeO3dw

OK, I'm going out on a limb...... getting way above my pay grade....... speculating even

But I THINK there's a difference between bombarding the powder with static sparks VS it actually discharging into a conductor. I think the test shown on the vid was kinda' like snuffing a lit cigarette in a container of gas. Looks "dangerous" but isn't.

A guy I went to explosives classes with got hurt because as he was folding powder it discharged thru the paper folding sheet. This was flash as opposed to BP but I've heard of three instances where BP ignited from static during mixing. Around here BP is mfgd using liquid to stabilize for this reason. OR, when a blender or ball mill is used there's a dedicated stump down on the rifle range where it sets!

We're kinda' safety geeks.....

al

 

[alinwa]

OK, my limb just broke.

I checked with my kid. He says that pure BP is very hard to ignite using a "plasma bolt" discharge because it has no metallic content.

He says that my thing about discharging being different than an outside bolt (like the vid) is completely false. The taser WOULD ignite it if ignition was going to happen. That the small dielectric charge and resultant static discharge would be LESS effective than the taser. In other words, the taser vid shows fairly conclusively that static charge ignition is very unlikely.

He said that flash powder mixes are easily initiated by static discharge because of the metallic content. (a common flash mix is metal powder and potassium perchlorate, it's quite unsafe, illegal to mfgr as a minor and illegal to store without BATFE approved facility)

He said that the BP mixes that have ignited from static were either firework mixes (which contain metallics for color) or mixes which had been coated with graphite. Yes it happens but not with pure BP.

Basically the ignition mechanism is that the plasma bolt heats the metallic particulates to above the ignition temp of the powder. OR, the powder has enough graphite to induce conductive heating in itself...

I'll just STOP now before I step in any deeper!


al

 

[K Hope]

Moisture and Anti Static coatings

Anecdotal and values unknown but, I believe static concerns are two fold.

First: Powder charges up readily through production, transportation and handling (Triboelectrically and Contact). Even before it reaches the powder measure and quite likely as it is leaving. Under certain conditions (Nonconductor Induction) if humidity is high; moisture (which is polar), coats the surface providing a low-resistance path for electron flow. Neutralizing the charge but picking up moisture.

Second: Powder’s hydrophobic properties combined with graphite’s poor wettability properties (Graphite Moisture Sensitivity) can lead to the formation of nodes and a non uniform product resulting in poor flowability (Agglomeration).


Ken